Space

Topic

[Sean Robinson]

I figured there needed to be a “Space” thread.
If the mods think it should be rolled into the Science thread, I have no problem with that.
If it’s the “nutjobs” this thread seems to pull in you’re worried about, just double-up on the tinfoil hat
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The following has been debunked. see post #9 on Dec.14th)
Toldya about the tinfoil hat…
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– Scientists Just Found an “Impossible” Black Hole in The Milky Way Galaxy
– A newfound black hole in the Milky Way is weirdly heavy
– Monster black hole that ‘should not exist’ discovered in the Milky Way

The chemical composition of our galaxy’s most massive stars suggests that they lose most of their mass at the end of their lives through explosions and powerful stellar winds, before the star’s core collapses into a black hole.

The hefty stars in the mass range that could produce a black hole are expected to end their lives in what is called a pair-instability supernova that completely obliterates the stellar core. So astronomers are scratching their heads trying to figure out how the black hole – named LB-1 – got so chonky.

“Black holes of such mass should not even exist in our galaxy, according to most of the current models of stellar evolution,” said astronomer Jifeng Liu of the National Astronomical Observatory of China.

“LB-1 is twice as massive as what we thought possible. Now theorists will have to take up the challenge of explaining its formation.”

• This topic was modified 4 years, 4 months ago by Sean Robinson.
• This topic was modified 4 years, 2 months ago by Sean Robinson.
• This topic was modified 3 years, 11 months ago by Sean Robinson.
• This topic was modified 3 years, 7 months ago by Sean Robinson.

Replies

DavidM wrote:

Sean Robinson wrote:

This visualization shows space radiation interacting with Earth’s magnetosphere.

No, it clearly shows a giant space spider about to ravage the Earth.

It can be two things!

1 user thanked author for this post.

Sean Robinson

Strange white dwarf switches ‘on’ and ‘off’ in front of astronomers

Scientists spotted the star’s behavior using a planet-hunting satellite.

An artist’s depiction of a white dwarf drawing matter from a companion star.

A spacecraft that usually seeks new worlds saw a white dwarf suddenly switch “off” with a swift drop in brightness. Then it switched back on again.

This observation represents the first time astronomers saw a white dwarf change its luminosity, or inherent brightness, so quickly, and may have implications for how we understand the process of accretion (or building up material) at many types of celestial objects.

White dwarfs are the remnants of much larger stars approximately the size of our sun that have burned off all the hydrogen that previously fueled them. As such, sometimes astronomers say that looking at white dwarf systems helps us learn about our own solar system’s distant future, when the sun runs out of hydrogen in about 5 billion years.

The new star research was conducted using NASA’s Transiting Exoplanet Survey Satellite (TESS), whose main mission is to seek Earth-size worlds relatively close to our own planet, on a larger quest to understand how prolific life may be in the universe. In this case, TESS spotted the fluctuating brightness at a star called TW Pictoris, which is roughly 1,400 light-years from Earth.

The luminosity changes took place because the white dwarf is pulling off material from a nearby companion star, in a process known as accretion. As the white dwarf “feeds” off its companion, it grows brighter.

The white dwarf lost luminosity in only 30 minutes, much faster than other white dwarfs that have faded over several days or months. Why is still unknown, as the flow of material on to the white dwarf’s accretion disc should be constant, but astronomers suspect it might be due to fluctuations in the dwarf’s magnetic field.

“The brightness of an accreting white dwarf is affected by the amount of surrounding material it feeds on, so the researchers say something is interfering with its food supply,” the University of Durham, which led the research, said in a statement.

“They hope the discovery will help them learn more about the physics behind accretion — where objects like black holes, white dwarfs and neutron stars feed on surrounding material from neighboring stars.”

The researchers theorize that when the star is “on,” the white dwarf is feeding off the accretion disc as expected. But when the star turns “off,” it’s possible that the magnetic field is spinning quite rapidly, too fast to allow the material from the companion star to settle on the white dwarf.

This process, which creates a centrifugal barrier blocking the material from falling on the white dwarf, is called “magnetic gating,” the researchers said. For reasons that are still being investigated, the white dwarf system then resets itself and turns “on” again, allowing the luminosity to increase.

“To see the brightness of TW Pictoris plummet in 30 minutes is in itself extraordinary as it has never been seen in other accreting white dwarfs and is totally unexpected,” lead author and Durham astronomer Simone Scaringi said in the statement.
Scaringi pointed to neutron stars, or the city-sized leftovers of large supernova star explosions, as possible analogs for the behavior. The new observations of the white dwarf, Scaringi added, “could be an important step in helping us to better understand the process of how other accreting objects feed on the material that surrounds them, and the important role of magnetic fields in this process.”

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Todd

Astronomers have found what may be the first exoplanet in another galaxy ever detected

The newly-detected object lies 28 million light-years away in the Whirlpool galaxy M51.

For the first time in history, scientists may have just discovered a planet in another galaxy.

The potential exoplanet, called M51-ULS-1b, lies 28 million light-years away in the spiral galaxy Messier 51 (M51), also known as the Whirlpool galaxy. This discovery could be just the tip of the iceberg, revealing many other exoplanets outside the Milky Way.

“We are trying to open up a whole new arena for finding other worlds,” Rosanne Di Stefano, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics who led the study which found this object, said in a statement.

Searching outside our galaxy

An artist’s illustration of a neutron star around a black hole in the Whirlpool Galaxy M51 that may host an exoplanet.

For this study, astronomers used NASA’s Chandra X-ray Observatory and the European Space Agency’s XMM-Newton space telescope to look at three galaxies beyond the Milky Way. In total, they looked at 55 different systems in M-51, the Whirlpool galaxy, 64 systems in Messier 101 (M-101), or the “Pinwheel galaxy,” and 119 systems in Messier 104, or the “Sombrero galaxy.”

The team spotted the object in M-51 using transits, which happen when an object transits, or passes, in front of a star. When it does this, it blocks some of the star’s light and creates a brief dimming. Previously, scientists have used this method to discover thousands of exoplanets, or planets outside of our solar system (but still in our galaxy).

The first exoplanet discovered was in 1992 and, since then, most exoplanets found have been less than 3,000 light-years from Earth.

But M51-ULS-1b, orbiting 28 million light-years away, would be the first exoplanet ever found in another galaxy.

This graphic shows the orientation of a neutron star or black hole and its companion star, as well as the orbit of a potential exoplanet in orbit.

To spot the planet, the team led by Di Stefano used Chandra to look for dips in the brightness of X-rays. Because X-rays are produced by small areas on stars, planets passing in front of those stars could actually block out those X-ray emissions entirely. So instead of a subtle dimming of optical light, researchers could see a more obvious transit, which could make it easier to see objects farther away, according to the statement.

“We are trying to open up a whole new arena for finding other worlds by searching for planet candidates at X-ray wavelengths, a strategy that makes it possible to discover them in other galaxies,” Di Stefano said.

They found the possible exoplanet in the Whirlpool galaxy in a binary system orbiting two large objects: either a neutron star or a black hole which orbits a massive companion star.

The transit they witnessed lasted a total of about three hours and the X-ray emissions dipped all the way to zero. This helped them to figure out that the object is likely approximately the size of Saturn and it orbits the neutron star (or a black hole) at a distance twice that of Saturn’s distance from our sun.

Confirming a discovery

An artist’s illustration of a neutron star around a black hole in the M51 Whirlpool Galaxy that may host an exoplanet.

This work could be the first to confirm a planet in another galaxy and potentially open up a whole new era of planet detection and study. But right now, these observations do not confirm that the object seen using Chandra in this study is a planet. More data needs to be collected in order to confirm this assertion, researchers said.

However, the object won’t transit in front of its star again for 70 years, so it will be a long time before scientists are able to make this observation again.

“Unfortunately to confirm that we’re seeing a planet we would likely have to wait decades to see another transit,” co-author Nia Imara, a researcher at the University of California at Santa Cruz, added in the same statement. “And because of the uncertainties about how long it takes to orbit, we wouldn’t know exactly when to look.”

It is possible, but highly unlikely, the researchers acknowledge in the statement, that the dimming could be caused by something like a cloud passing in front of the star. Still, the team has shared that they expect other scientists to look at the data they’ve collected and what they’ve found. This could help to verify what they have detected and move this research along, despite the decades left until the next transit.

“We know we are making an exciting and bold claim so we expect that other astronomers will look at it very carefully,” co-author Julia Berndtsson, a researcher at Princeton University in New Jersey, added in the same statement. “We think we have a strong argument, and this process is how science works.”

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Todd

Earth tipped on its side (and back again) in ‘cosmic yo-yo’ 84 million years ago

The planet would’ve looked a little weird.

A new study has confirmed a longstanding theory that the Earth’s crust was tilted on its side around 84 million years ago.

Earth has not always been upright. Turns out, the planet’s crust tipped on its side and back again around 84 million years ago, in a phenomenon that researchers have dubbed a “cosmic yo-yo.”

The actual name for the tipping is true polar wander (TPW), which occurs when the outer layers of a planet or moon move around its core, tilting the crust relative to the object’s axis. Some researchers had previously predicted that TPW occurred on Earth late in the Cretaceous period, between 145 million and 66 million years ago, but that was hotly debated, according to a statement by the researchers.

However, the new study strongly suggests TPW did occur on Earth. Researchers mapped the ancient movement of Earth’s crust by looking at magnetic-field data trapped inside ancient fossilized bacteria. They found that the planet tilted 12 degrees relative to its axis around 84 million years ago, before fully returning to its original position over the next 5 million years.

“This observation represents the most recent large-scale TPW documented and challenges the notion that the [Earth’s] spin axis has been largely stable over the past 100 million years,” the researchers wrote in their paper, published online June 15 in the journal Nature Communications.

Cosmic yo-yo

Earth is made out of four main layers: the solid inner core, the liquid outer core, the mantle and the crust. During TPW, the entire planet would appear turned over on its side, but in reality only the outermost layers have moved.

“Imagine looking at Earth from space, TPW would look like the Earth tipping on its side,” co-author Joe Kirschvink, a geobiologist at the Tokyo Institute of Technology in Japan and a professor at the California Institute of Technology, said in the statement. “What’s actually happening is that the whole rocky shell of the planet [the mantle and crust] is rotating around the liquid outer core.”

During TPW the Earth’s crust rotates around the outer core, but the planet’s axis and magnetic field remains the same.

Individual pieces of Earth’s outermost layers are constantly moving and changing as tectonic plates collide together and subduct underneath one another; but during TPW, the outer layers move together as a single unit.

As a result, the tilt in Earth’s crust would not have resulted in any major tectonic activity or drastic changes to major ecosystems. Instead, it would have been a gradual process that would not have impacted the dinosaurs and other living things walking around on the surface.

Earth’s electromagnetic field would have been static during the TPW because it is created by the liquid inner core, which would have stayed in place. So rather than the magnetic poles moving, it is the geographic poles that start to wander.

Fossilized magnets

To test if Earth did undergo TPW during the Cretaceous, the researchers turned to magnetic minerals within limestone deposits in Italy.

“These Italian sedimentary rocks turn out to be special and very reliable because the magnetic minerals are actually fossils of bacteria that formed chains of the mineral magnetite,” co-author Sarah Slotznick, a geobiologist at Dartmouth College in New Hampshire, said in the statement.

The limestone deposits in Italy which contain the fossilized magnetite (left) and the drill holes leftover from where researchers extracted some of their samples (right).

Magnetite is a highly magnetic form of iron-oxide. Some types of bacteria can create chains of tiny magnetite crystals, which naturally orient with Earth’s magnetic field at the time of their creation. When these particular bacteria died and were fossilized during the period of TPW, these magnetite chains got locked in place.

Because Earth’s crust moved during TPW, and not its magnetic field, these magnetic fossils (which remained in surface layers of the planet) revealed how much the crust moved relative to Earth’s magnetic field over time. The team found that Earth’s crust moved a total of almost 25 degrees over a period of 5 million years.

The researchers believe that their findings now settle the question of whether Earth had a TPW during the Cretaceous.

“It is so refreshing to see this study with its abundant and beautiful paleomagnetic data,” Richard Gordon, a geophysicist at Rice University in Houston who was not involved in the study, said in the statement.

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Todd

Enormous ‘shipyard’ of ancient galaxies discovered 11 billion light-years away

A similar protocluster may have created our Milky Way.

An image of the G237 protocluster with its galaxies in different colors representing different wavelengths of observations.

Astronomers have discovered a massive “shipyard” where galaxies are built, similar to the one our Milky Way grew up in.

The giant structure, called a protocluster, contains more than 60 galaxies and is 11 billion light-years from Earth, so far away that scientists are observing a part of the universe that is only 3 billion years old.

More in link…
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This bizarre ‘superbubble’ spotted by the Hubble Space Telescope has scientists scratching their heads

Scientists aren’t exactly sure how it formed.

A Hubble Space Telescope image of a nebula called N44

Wispy clouds of gas and a strange “superbubble” dominate the view of a new Hubble Space Telescope image.

The view stars a nebula, or gas cloud, known as N44, that is located in a nearby galaxy called the Large Magellanic Cloud. In the newly released image, you can see hydrogen gas glowing in the dark, along with dark dust lanes and stars of all ages, in a complex structure roughly 170,000 light-years from Earth.

NASA said the “superbubble,” which appears in the upper central part of the gas cloud, is of particular interest because scientists are trying to figure out how the 250-light-year wide structure formed.

More in link…
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Weird cosmic object keeps exploding over and over again, and scientists don’t know why

An odd fast radio burst has been seen exploding over and over.

Astronomers have watched a mysterious cosmic object shoot out 1,652 blasts of energy over a short period of time. Though researchers are still stumped as to what caused the repeated eruptions, they hope the observations will help them get closer to an answer.

The entity in question is called a fast radio burst (FRB), an enigmatic phenomenon first observed in 2007. FRBs produce pulses in the radio part of the electromagnetic spectrum; these pulses last only a few thousandths of a second but produce as much energy as the sun does in a year.

Some FRBs emit energy just once, but several — including an object called FRB 121102, located in a dwarf galaxy 3 billion light-years away — are known to repeat their bursts. Using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China, a team of scientists decided to conduct an extensive study of this repeating FRB.

More in link…

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Todd

Astronomers target habitable exoplanets, black holes and inclusivity as top priorities for next decade

A new big space telescope is also on the list for the latest “decadal survey.”

An artist’s impression of an Earthlike exoplanet orbiting a star similar to our own sun.

We now have a rough sketch of what the next decade could bring in astronomy and astrophysics.

Today (Nov. 4), the U.S. National Academies of Sciences, Engineering, and Medicine released a “decadal survey” laying out scientific priorities and funding recommendations for the next 10 years of astronomy and astrophysics research.

The document, called “Pathways to Discovery in Astronomy and Astrophysics for the 2020s,” identifies three top-line items the disciplines should concentrate on: the discovery and study of habitable exoplanets, the exploration of black holes and neutron stars as windows to the early universe, and a better understanding of the origin and evolution of galaxies. It also stresses the importance of making astronomy a more inclusive and diverse field.

“This report sets an ambitious, inspirational and aspirational vision for the coming decade of astronomy and astrophysics,” Fiona Harrison, co-chair of the National Academies’ steering committee for the survey, said in a statement.

“In changing how we plan for the most ambitious strategic space projects, we can develop a broad portfolio of missions to pursue visionary goals, such as searching for life on planets orbiting stars in our galactic neighborhood — and at the same time exploit the richness of 21st-century astrophysics through a panchromatic fleet,” added Harrison, who chairs the division of physics, mathematics and astronomy at the California Institute of Technology in Pasadena.

An influential document

The National Academies prepares decadal surveys for a variety of fields, including planetary science and Earth science. As the name suggests, they come out every 10 years or so; the last astronomy and astrophysics decadal — “New Worlds, New Horizons in Astronomy and Astrophysics” — was released in 2010. (The new report was delayed by nearly a year by the coronavirus pandemic and a government shutdown; it was supposed to be released in January 2021.)

A lot of work goes into these documents, which are drawn up by prominent researchers in the fields that they cover. The newly released survey, for example, is 614 pages long.

“‘Pathways to Discovery in Astronomy and Astrophysics for the 2020s’ drew from the astronomical community through hundreds of white papers, town hall meetings and the advice of 13 sub-panels over several years to produce its recommendations,” National Academies representatives wrote in the statement.

Decadal surveys are incredibly influential; government agencies such as NASA and the National Science Foundation (NSF) rely on them to decide how to allocate funding and other resources. For example, the 2001 astronomy and astrophysics decadal identified the Next Generation Space Telescope as the highest-priority mission to develop over the next 10 years. That ambitious observatory, now known as the James Webb Space Telescope, is scheduled to launch from French Guiana on Dec. 18.

In 2010, “New Worlds, New Horizons” flagged the Wide-Field Infrared Survey Telescope (WFIRST) and the Large Synoptic Survey Telescope (LSST) as especially important projects. And both are now progressing toward operation, though not without some drama. WFIRST, now known as the Nancy Grace Roman Space Telescope, is scheduled to lift off no later than May 2027, and the ground-based LSST, now called the Vera C. Rubin Observatory, will open its eyes in 2022 or 2023, if all goes according to plan.

Three areas of focus, and a new ‘Great Observatories’ program

The newly released survey identifies three “priority areas” that should receive special attention and investment over the coming decade.

One, called “Pathways to Habitable Worlds,” is a program designed to help discover and characterize Earth-like exoplanets, with the goal of eventually capturing photos of such worlds and analyzing their atmospheric composition.

The second, “New Windows on the Dynamic Universe,” describes an intensified effort to study black holes and neutron stars with a diversity of instruments on the ground and in space, including gear that detects gravitational waves. Gaining a better understanding of these exotic, superdense objects could shed considerable light on the very early universe, the report’s authors wrote.

The third focus area, “Unveiling the Drivers of Galaxy Growth,” aims to revolutionize scientists’ understanding of galaxy formation and evolution, “from the nature of the tenuous cosmic webs of gas that feed them, to the nature of how this gas condenses and drives the formation of stars,” the decadal survey states.

To help achieve these and other ambitious goals, the survey recommends the establishment of a “Great Observatories Mission and Technology Maturation Program” — a callback to NASA’s Great Observatories program, which launched four powerful space telescopes from 1990 to 2003, starting with the iconic Hubble Space Telescope.

The new Great Observatories effort “would provide significant early investments in the co-maturation of mission concepts and technologies, with appropriate decadal survey input on scope, and with checks and course corrections along the way,” according to the new decadal.

The survey also recommends that this program’s first mission should be an infrared/optical/ultraviolet (IR/O/UV) space telescope with a primary mirror about 19.7 feet (6 meters) across. That’s about 2.5 times wider than Hubble’s mirror and roughly the same size as that of Webb, which is optimized to view the cosmos in infrared light.

This envisioned space telescope could search for biosignatures in the atmospheres of about 25 potentially habitable exoplanets and be ready for launch in the early 2040s, the survey determined. And its mission could be mounted for about $11 billion, if all goes well — roughly the same price tag as Webb, whose total cost is about $10 billion.

The goals of this proposed IR/O/UV space telescope are broadly similar to those of two concept missions that NASA has been developing since 2016 — the Large Ultraviolet Optical Infrared Surveyor (LUVOIR) and the Habitable Exoplanet Observatory (HabEx).

There are two potential LUVOIR variants, which would boast primary mirrors 49.2 feet (15 m) and 26.2 feet (8 m) wide, respectively. HabEx’s primary mirror would be 13 feet (4 m) across.

The IR/O/UV space telescope recommended by the decadal is a middle ground between those options: it would be more capable than HabEx and could be developed more quickly and cost-effectively than either LUVOIR version, according to the document.

Other Great Observatories would follow the new IR/O/UV space telescope in relatively quick succession, if the vision laid out in the new decadal comes true. Five years after work on that first scope gets underway, “the survey recommends commencing mission and technology maturation of both a far-IR and an X-ray large strategic mission, both scoped to have implementation costs in the $3 billion to $5 billion range,” the new report states.

The decadal survey also recommends making key investments in huge ground-based telescopes — especially the Giant Magellan Telescope, which is currently being built in the Chilean Andes, and the Thirty Meter Telescope, which is slated to be constructed in Hawaii but has met with opposition in the state.

Such investments would ideally be made “as components of a coordinated U.S. Extremely Large Telescope Program (ELT) program,” the survey states. “These observatories will create enormous opportunities for scientific progress over the coming decades and well beyond, and they will address nearly every important science question across all three priority science areas.”

Making astronomy and astrophysics more inclusive

The decadal also stresses that more investment is needed to support research facilities, early-career scientists and important activities such as data archiving.

Both astronomy and astrophysics are male-dominated fields, with representation of minoritized groups lower than that of society at large — a situation that the new report would like to help change.

“Funding to support diverse faculty in university astronomy and astrophysics programs should be increased,” the survey states.

“Among other steps, the report recommends NASA, NSF and the U.S. Department of Energy (DOE) ensure their policies treat harassment and discrimination as forms of scientific misconduct, and invest in workforce diversity at the division and directorate levels — as well as consider including the diversity of project teams and participants as a criterion when awarding funding,” it adds. “NSF and NASA should implement funding for traineeship and postdoctoral fellowships to develop diverse and inclusive excellence.”

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Rocket, Todd

Astronomers spot small black hole beyond the Milky Way in milestone discovery

Scientists hope it’s the first of many.

Finding a black hole isn’t straightforward, and it’s even harder the more distant such a behemoth is.

Because black holes absorb all flavors of light, telescopes typically can’t see them directly. But any black hole will leave fingerprints: for instance, its gravity will influence the movements of objects around it — and those objects, telescopes can study. Now, chasing one such clue, astronomers have found a black hole in a cluster just outside the Milky Way, making it the first black hole ever spotted beyond our own galaxy with this technique.

The astronomers made the discovery using the European Southern Observatory’s Very Large Telescope (VLT), which is perched atop a desert mountain in northern Chile. The researchers turned the VLT’s eyes upon NGC 1850, a cluster nestled in the neighboring Large Magellanic Cloud about 160,000 light-years away from Earth. Here, scientists could look at thousands of stars in one go.

An artist’s depiction of a black hole and star orbiting each other in star cluster NGC 1850.

“Similar to Sherlock Holmes tracking down a criminal gang from their missteps, we are looking at every single star in this cluster with a magnifying glass in one hand, trying to find some evidence for the presence of black holes but without seeing them directly,” Sara Saracino, an astrophysicist at Liverpool John Moores University in England, said in a statement.

The researchers observed the stars’ motions to find any signs of a ghostly black hole. The smoking gun, as it were, was a humble star about five times the sun’s mass. The astronomers found subtle blips in that star’s motions: the telltale sign of the black hole that star was orbiting.

The culprit? A black hole with around 11 times the mass of the sun. Its home, a star cluster called NGC 1850, is only about 100 million years old, practically an infant by cosmic scales. No black hole, the astronomers say, has ever been discovered in a cluster that young.

A Hubble Space Telescope image of star cluster NGC 1850, which is located in the Large Magellanic Cloud.

The research will be published in the Monthly Notices of the Royal Astronomical Society. Now, the researchers think the same technique can help find other black holes in other dark corners of the universe, helping us understand how these strange objects age and develop.

“The result shown here represents just one of the wanted criminals,” said Saracino, “but when you have found one, you are well on your way to discovering many others, in different clusters.”

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Todd

What time is the Beaver Moon lunar eclipse?

The longest partial lunar eclipse in more than half a millennium is coming up Friday (Nov. 19), and here’s where to watch it.

The Beaver Moon lunar eclipse will be visible in North America, South America, much of Europe, much of Asia, Australia, north and west Africa, the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, and the Arctic, according to Time and Date. There also are several online broadcasts if you are clouded out in your region.

You’ll be able to watch the Beaver moon lunar eclipse online here and on the Space.com homepage. The webcasts begin at 1:02 a.m. EST (0602 GMT)

What time is the lunar eclipse?

Assuming your region is able to see the full eclipse, the penumbral eclipse (when the moon passes into the darker part of the Earth’s shadow) will start at 1:02 a.m. EST (0602 GMT), according to NASA. The partial eclipse, during which the moon goes into the umbra or the darker part of the Earth’s shadow, will start at 2:18 a.m. EST (0718 GMT).

Maximum eclipse is at 4:02 a.m. EST (0902 GMT), during which the moon may turn a dark red or a ruddy brown color. This is due to the refraction of light around the edges of the Earth, falling on to the moon’s face. Another way to think about it is you are seeing the reflection of sunrises and sunsets on the lunar surface.

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Todd

Wormholes may be viable shortcuts through space-time after all, new study suggests

The new theory contradicts earlier predictions that these ‘shortcuts’ would instantly collapse.

Wormholes, or portals between black holes, may be stable after all, a wild new theory suggests.

The findings contradict earlier predictions that these hypothetical shortcuts through space-time would instantly collapse.

The sea change comes because tiny differences in the mathematics of relativity, which is used to describe such wormholes, end up dramatically changing our overall picture of how they behave.

A game of metrics

First, some background on how general relativity operates. Relativity is like a machine. Put in certain objects — say, a mass or an arrangement of particles — and the machine spits out how that collection will behave over time due to gravity. Everything in general relativity is based on movement in space and time: Objects start at certain physical coordinates, they move around, and they end up at other coordinates.

While the rules of general relativity are fixed, the theory itself provides a lot of freedom to describe those coordinates mathematically. Physicists call these different descriptions “metrics.” Think of the metric as different ways to describe g how to get to your grandma’s house for Thanksgiving. That may be street directions, satellite-based latitude and longitude, or landmarks scribbled on a napkin. Your metric is different in each case, but no matter which metric you choose, you end up at the big feast.

Similarly, physicists can use different metrics to describe the same situation, and sometimes one metric is more helpful than another — akin to starting off with the street directions, but switching over to the napkin to double-check if you’re at the right landmark.

The extended black hole

When it comes to black holes and wormholes, there are a few potential metrics. The most popular one is the Schwarzschild metric, which is where black holes were first discovered. But the Schwarzschild metric contains some funky math. That metric misbehaves at a particular distance from the black hole, a distance known today as the Schwarzschild radius or the event horizon.

And by “misbehaves,” we mean that metric completely breaks down, and it can no longer distinguish between different points in space and time. But there’s another metric, called the Eddington-Finkelstein metric, that does describe what happens to particles when they reach the event horizon: They pass right through and fall into the black hole, never to be seen again. What does all this have to do with wormholes? The simplest way to construct a wormhole is to “extend” the idea of a black hole with its mirror image, the white hole. This idea was first proposed by Albert Einstein and Nathan Rosen, hence the reason wormholes are sometimes called “Einstein-Rosen bridges.” While black holes never let anything out, white holes never let anything in. To make a wormhole, you just take a black hole and a white hole and join their singularities (the points of infinite densities in their centers). This creates a tunnel through space-time.

The result? A highly misbehaving tunnel.

A narrow path

Once a theoretical wormhole exists, it’s perfectly reasonable to ask what would happen if someone actually tried to walk through it. That’s where the machinery of general relativity comes in: Given this (very interesting) situation, how do particles behave? The standard answer is that wormholes are nasty. White holes themselves are unstable (and likely don’t even exist), and the extreme forces within the wormhole force the wormhole itself to stretch out and snap like a rubber band the moment it forms. And if you try to send something down it? Well, good luck.

But Einstein and Rosen constructed their wormhole with the usual Schwarzschild metric, and most analyses of wormholes use that same metric. So physicist Pascal Koiran at Ecole Normale Supérieure de Lyon in France tried something else: using the Eddington-Finkelstein metric instead. His paper, described in October in the preprint database arXiv, is scheduled to be published in a forthcoming issue of the Journal of Modern Physics D.

Koiran found that by using the Eddington-Finkelstein metric, he could more easily trace the path of a particle through a hypothetical wormhole. He found that the particle can cross the event horizon, enter the wormhole tunnel and escape through the other side, all in a finite amount of time. The Eddington-Finkelstein metric didn’t misbehave at any point in that trajectory.

Does this mean that Einstein-Rosen bridges are stable? Not quite. General relativity only tells us about the behavior of gravity, and not the other forces of nature. Thermodynamics, which is the theory of how heat and energy act, for example, tells us that white holes are unstable. And if physicists tried to manufacture a black hole-white hole combination in the real universe using real materials, other math suggests the energy densities would break everything apart.

However, Koiran’s result is still interesting because it points out that wormholes aren’t quite as catastrophic as they first appeared, and that there may be stable paths through wormhole tunnels, perfectly allowed by general relativity.

If only they could get us to grandma’s faster.

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Todd

Sean Robinson wrote:

You’ll be able to watch the Beaver moon lunar eclipse online here and on the Space.com homepage.

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Rocket, Todd, Sean Robinson

Just how many threatening asteroids are there? It’s complicated.

You don’t have anything to worry about right now, scientists emphasize.

An animation showing the location of the near-Earth asteroids discovered as of January 2018; Earth’s orbit is marked by the white line.

So you’ve heard that an asteroid could slam into Earth wreaking all sorts of havoc, but just how many space rocks out there actually threaten our planet?

It’s complicated, because the answer depends on what you mean by threaten.

Let’s start with the most important takeaway: NASA knows of zero asteroids large enough to do meaningful damage on Earth and currently on track to collide with our planet in the foreseeable future. But large asteroids hanging around Earth? We’ve spotted plenty of those, and scientists are discovering new near-Earth asteroids practically daily, with more than 27,000 identified to date.

“We’re racking up the numbers for these populations, but at the same time, there is no known threat right now to Earth,” Kelly Fast, who is a near-Earth object observations program manager at NASA’s Planetary Defense Coordination Office, told Space.com. “There’s nothing, there’s no asteroid that we know of that poses a significant threat to Earth.”

And while it may seem paradoxical, the constant rise in near-Earth asteroid tallies turns out to be the best news possible if you’re worried about a potential asteroid impact.

The two parts of planetary defense

The art of protecting Earth from an asteroid impact is called planetary defense, and there are two key stages to the process. NASA’s Double Asteroid Redirection Test (DART), launching later this month, is a mission designed to test the second stage of planetary defense, diverting a threatening asteroid from crossing paths with Earth.

But before anyone can even try to divert an asteroid, scientists have to find the space rock and map out its orbit many years into the future to realize that it will or may hit Earth.

“People might think planetary defense is all about deflecting asteroids but it’s not,” Nancy Chabot, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Maryland and the coordination lead for DART, told Space.com. “Keeping track of the actual asteroids, identifying them and finding them is really crucial toward being able to do anything about them in the future.”

Scientists have identified some 750,000 asteroids to date, but suspect there are millions of space rocks ricocheting through the full solar system. Fortunately, plenty of those stay far, far from Earth — consider, for example, residents of the main asteroid belt or the Trojan asteroids that flank Jupiter in its orbit.

In Earth’s neck of the woods, that number comes down somewhat: Scientists have identified more than 27,000 near-Earth asteroids, with new ones spotted daily.

A chart showing the total number of near-Earth asteroids identified over the years and split into categories based on size.

A bonanza of discoveries

Those discoveries are thanks to a team of instruments on Earth and in space that dedicate some or all of their time to spotting and cataloging asteroids. The vast majority of these discoveries have come since the late 1990s, although experts were warning of the threat posed by asteroids before then without much success.

“If you talk to the scientists who were studying this in the ’80s, there’s a phrase they often refer to called the giggle factor,” Carrie Nugent, a planetary scientist at Olin College in Massachusetts, told Space.com. “They’re basically saying that they couldn’t talk about this scientific topic without people kind of laughing at them.”

The work was quite difficult then, as well, with surveys relying on photographic film developed in a darkroom then used with a device that helped a human brain recognize asteroids moving against background stars. Now, modern cameras and computer programs can bear much of the brunt of identification work.

So the rise of asteroid detections has been in part a matter of technology. But increasing funding was also key, which made reducing the giggle factor vital.

One milestone was Comet Shoemaker-Levy 9’s impact of Jupiter in 1994, which unexpectedly left a mark in Jupiter’s clouds the size of Earth that lingered for months. “People started to think, ‘Whoa, if that happened to Jupiter, what would happen if that hit Earth?'” Nugent said.

Congress got on board with prioritizing asteroid hunting, calling on NASA to identify at least 90% of first the largest asteroids, then medium ones. Today, there’s a whole host of projects that detect near-Earth asteroids, whether it’s their top priority or an opportunity they can make use of.

An artist’s depiction of the NEOWISE mission, which began searching for asteroids after completing an astrophysics mission as WISE.

Leading the charge today are programs like the Catalina Sky Survey based in Arizona that specializes in catching smaller asteroids, the Pan-STARRS observatory in Hawaii that excels at spotting faint objects, the NEOWISE space telescope that can see the whole sky and the ATLAS telescopes in Hawaii that are tuned to the fastest-moving objects.

“It’s kind of like the ecosystem, everyone has their role,” Nugent said. “Everyone kind of works together with their own strengths to really cover the sky.”

Others chip in when luck permits. “Wide-field survey telescopes are set up for other purposes like for astrophysics investigations for instance, and then they end up getting the asteroids that photobomb them,” Fast said.

And asteroid hunters are looking forward to a few new instruments joining the team soon. Planetary defenders are particularly excited to see the Vera C. Rubin Observatory in Chile begin observing in 2023; a space-based mission called NEO Surveyor is also in development and scheduled to launch later this decade.

“There’s been a lot of work done to predict how many objects both [missions] will find, and those numbers are incredibly large,” Nugent said. “It should be a huge increase in the number of asteroids and comets found, and that’s always really exciting.”

But surveys on their own aren’t enough for planetary defense experts — follow-up observations are crucial to give scientists the data they need to accurately calculate an object’s orbit. “That’s the key part there,” Fast said. “You want to know the asteroid’s there, but you really want to know where it’s going to be in the future and whether Earth is going to be in the same place at the same time.”

A diagram showing the orbit of every potentially hazardous asteroid identified by early 2013, more than 1,400 objects in total. Today, scientists track more than 2,000 potentially hazardous asteroids.

Recipe for a “potentially hazardous asteroid”

If all those observations find that an asteroid is over a certain brightness (which suggests a certain size, although the two factors don’t correlate precisely) and will come within 4.65 million miles (7.48 million kilometers) of Earth, the object is automatically dubbed a “potentially hazardous asteroid.” (The distance works out to one-twentieth of the average distance between Earth and the sun.)

But in most cases, despite the ominous terminology, “potentially hazardous asteroids” may as well be called “not currently hazardous asteroids.” After all, these are the objects that scientists have already found, and followed, and mapped, and forecast into the future.

“It’s not like I look at a potentially hazardous object and, like, break out into a cold sweat,” Nugent said. “It just means that it’s something we want to keep an eye on.”

To those who dedicate their careers to watching the skies for an apocalypse, the asteroids not yet identified are far more terrifying; these asteroids are the ones that can pop up, suddenly uncomfortably close to Earth, too late for anyone to even try to change a rock’s course.

Scientists believe they’ve found nearly all the largest asteroids — those larger than 3,300 feet (1 km) across — and know that these are the easiest to find anyway. And while tiny near-Earth asteroids are plentiful and difficult to find, they are also the most likely to fall apart harmlessly in Earth’s atmosphere.

So it’s the middle size category of asteroids — those more than 460 feet (140 meters) but less than 3,300 feet wide — that most worries planetary defense experts. “That’s where it’s more likely that an impact could happen,” Fast said. “Even with those, we’re talking maybe timescales of centuries or millennia.”

As of the end of 2020, estimates suggested scientists have found just 40% of near-Earth objects of this size; this year has added 500 to the tally. While that number is impressive, NASA’s planetary defense office estimates that at the current pace, it will take scientists 30 more years to have identified 90% of objects this size, a goal that Congress asked NASA to reach by 2020.

“There’s more of them as you go down in size and we’re still racking up the numbers every year,” Fast said. “That’s why the surveys are doing their job every night, so we aren’t caught unaware.”

The quest to map as many nearby asteroids as possible is why the tally of “potentially hazardous asteroids” and near-Earth objects in general is rising so dramatically. “It’s so satisfying to see that number of asteroid discoveries creep up,” Nugent said. “That feels good, it feels like you’ve accomplished something.”

It’s not just satisfying, she added — it’s even comforting.

“I think it’s a really nice example of science working,” Nugent said. “You have a problem that seems scary, you work to understand it, it seems less scary because you know what you need to do. I think that’s a really nice, calming thing about studying near-Earth asteroids.”

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Todd

Sean Robinson wrote:

the giggle factor,”

that is 1 of the main reasons I come into this thread.

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Sean Robinson

Giant black hole inside a tiny satellite galaxy of our Milky Way defies explanation

“There is no explanation for this kind of black hole in dwarf spheroidal galaxies.”

The Leo I dwarf galaxy has an enormous black hole at its center.

A tiny galaxy orbiting at the outskirts of the Milky Way appears to have a giant black hole at its center, comparable to that of the much larger Milky Way itself, and scientists don’t know why.

The Leo I dwarf galaxy, some 820,000 light-years from Earth, is only about 2,000 light-years across. Until now, astronomers thought the galaxy’s mass was about 15 to 30 million times the mass of our sun. That’s tiny compared to the Milky Way, which is estimated to weigh as much as 1.5 trillion suns and whose disk is over 100,000 light-years wide.

Unexpectedly, at the heart of the little Leo I sits a black hole that is nearly as large as the one at the heart of the entire Milky Way, a new study found. The discovery defies expectations as astronomers believed giant black holes grow from collisions between galaxies and should correspond with the galaxy’s size.

“There is no explanation for this kind of black hole in dwarf spheroidal galaxies,” María José Bustamante, an astronomy doctoral graduate at the University of Texas, Austin and lead author of the new paper, said in a statement.

The discovery came rather by chance. The scientists originally set out to measure the amount of dark matter in Leo I using the Virus-W instrument on the University of Texas’ McDonald Observatory’s 2.7-meter Harlan Telescope. Virus-W measures the motion of stars in small galaxies around the Milky Way and infers the amount of dark matter in those galaxies from those motion. Dark matter is the mysterious invisible stuff that counteracts the force of gravity. Scientists can measure its concentrations in the universe based on its effects on orbits and velocities of nearby stars. The more dark matter in the star’s orbit, the faster it travels.

When the team ran data gathered in the observations through their computer models, they found that Leo I appears to have basically no dark matter but a black hole at its center as heavy as 3 million suns. (The Sagittarius A* black hole at the center of the Milky Way is only 25% larger.)

“You have a very small galaxy that is falling into the Milky Way, and its black hole is about as massive as the Milky Way’s,” Karl Gebhardt, an astrophysicist at the University of Texas, Austin, and a co-author of the new study, said in the statement. “The mass ratio is absolutely huge.”

The results differ from previous calculations of dark matter in the Leo I galaxy, the astronomers admitted in the statement. The previous studies, they said, were based on less precise data and didn’t have access to such powerful supercomputers as the Austin team.

In previous studies, scientists didn’t see the denser inner regions of the galaxy and mostly focused on accessible information about a few individual stars. These data sets, however, seemed to contain a disproportionate number of slow stars. Calculations based on these biased dataset then failed to reveal the dark matter in the inner regions. In the case of Leo I, the amount of dark matter in the previously unseen central regions appears much higher than that at the fringes.

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Milky Way galaxy: Facts about our galactic home

The Milky Way galaxy is our home in space We live in the golden era of Milky Way research.

Motions of stars in the Milky Way galaxy in the next 400 thousands years based on data from the European Gaia mission.

Studying the Milky Way used to be notoriously difficult. Astronomers sometimes compare the effort to attempting to describe the size and structure of a forest while being lost in the middle of it. From our position on Earth, we simply lack an overview. But two ground-breaking space telescopes launched since the 1990s have helped usher in the golden age of Milky Way research. Major strides have been made, especially since the 2013 launch of the European Space Agency’s (ESA) Gaia mission.

Visible in the night sky (where light pollution permits) as a mesmerizing glowing band of stars and dust, the Milky Way has fascinated humans for millennia. Attempts to chart the galaxy date back to ancient Greece. But it wasn’t until the 1920s that astronomers realized that the Milky Way is only one of many galaxies populating the universe. Up until then, most believed the Milky Way and the universe were one.

American astronomer Edwin Hubble, the one in whose honor the famous space telescope was named, cracked the mystery when he managed to determine the distance of the Andromeda nebula. This fuzzy object, known since the 18th century, was originally thought to be just a different kind of star in the Milky Way. But Hubble’s observations proved that Andromeda was much too far away and was, in fact, a galaxy on its own, just like the Milky Way. Since then, astronomers have learned that Andromeda will one day bring about the end of our galaxy as we know it when the two collide some 4 to 5 billion years from now.

Since Hubble’s time, astronomers have figured out that there are billions of galaxies in the universe of various shapes and sizes. And they’ve made major strides in understanding the Milky Way.

THE MILKY WAY: HOW BIG IS IT AND WHAT IS ITS STRUCTURE?

Our Milky Way galaxy is about 100,000 light-years across and is a spiral galaxy in structure.

Improving telescope technology enabled astronomers to distinguish the basic shape and structure of some of the closest galaxies before they knew they were looking at galaxies. But reconstructing the shape and structure of our own galactic home was slow and tedious. The process involved building catalogs of stars, charting their positions in the sky and determining how far from Earth they are.

Dutch astronomer Jan Oort, sometimes dubbed the master of the galactic system, was the first to realize that the Milky Way isn’t motionless but rotates, and he calculated speeds at which stars at various distances orbit around the galactic center. It also was Oort who determined the position of our sun in the vast galaxy. (The Oort Cloud, a repository of trillions of comets far from the sun, was named after him.)

Gradually, a complex picture emerged of a spiral galaxy that appears quite ordinary.

At the center of the Milky Way sits a supermassive black hole called Sagittarius A*. With a mass equal to that of four million suns, the black hole, discovered in 1974, can be observed in the sky with radio telescopes close to the constellation Sagittarius.

Everything else in the galaxy revolves around this powerful gateway to nothingness. In its immediate surroundings is a tightly packed region of dust, gas and stars called the galactic bulge. In the case of the Milky Way, this bulge is peanut-shaped, measuring 10,000 light-years across, according to ESA. It harbors 10 billion stars (out of the Milky Way’s total of about 200 billion), mostly old red giants, which formed in the early stages of the galaxy’s evolution.

Beyond the bulge extends the galactic disk. This feature is 100,000 light-years across and 1,000 light-years thick, and it’s home to the majority of the galaxy’s stars, including our sun. Stars in the disc are dispersed in clouds of stellar dust and gas. When we look up to the sky at night, it’s the edge-on view of this disc extending toward the galactic center that takes our breath away.

The structure of the Milky Way galaxy as seen from above the galactic disk.

Stars in the disk orbit around the galactic center, forming swirling streams that appear to emanate like arms from the galactic bulge. Research into the mechanisms that drive the creation of the spiral arms is still in its infancy, but the latest studies suggest that these arms form and disperse within relatively short periods of time of up to 100 million years (out of the galaxy’s 13 billion years of evolution).

Inside those arms, stars, dust and gas are more tightly packed than in the more loosely filled areas of the galactic disc, and this increased density triggers more intense star formation. As a result, stars in the galactic disc tend to be much younger than those in the bulge.

“Spiral arms are like traffic jams in that the gas and stars crowd together and move more slowly in the arms. As material passes through the dense spiral arms, it is compressed and this triggers more star formation,” Denilso Camargo, of the Federal University of Rio Grande do Sul in Brazil, said in a statement.

The Milky Way currently has four spiral arms. There are two main arms — Perseus and Scutum-Centaurus — and the Sagittarius and Local Arm, which are less pronounced. Scientists still discuss the exact position and shape of these arms using Gaia data.

The disk is not flat but warped. As it rotates, it precesses like a wobbling spinning top, according to ESA. This wobble, essentially a giant ripple, circles the galactic center much more slowly than the stars in the disc, completing a full rotation in about 600 to 700 million years (for comparison, it takes our sun 230 million years to complete one lap.) Astronomers think this ripple may be a result of a past collision with another galaxy.

Sprinkled around the disc and the bulge are globular clusters, collections of ancient stars, as well as approximately 50 dwarf galaxies that are either orbiting or colliding with the larger Milky Way.

The structure of the Milky Way with its rotating warped galactic disc.

All of that is surrounded by a spherical halo of dust and gas, which is twice as wide as the disc. Astronomers believe that the entire galaxy is embedded in an even larger halo of invisible dark matter. Since dark matter doesn’t emit any light, its presence can only be inferred indirectly by its gravitational effects on the motions of stars in the galaxy. Calculations suggest that this puzzling stuff makes up to 90% of the galaxy’s mass.

“Even though we know the dark matter should be there, [and] we think it should be there, the ratio of dark matter to luminous matter in particular galaxies may be under debate,” Gwendolyn Eadie, a Ph.D. candidate in astrophysics at McMaster University in Ontario, Canada, and co-author on the research, told Space.com.

The mass of the Milky Way, dark matter included, equals 1.5 trillion solar masses, according to recent estimates. The galaxy’s visible matter is distributed between its 200 billion stars, their planets and the massive clouds of dust and gas that fill the interstellar space.

WHERE IS THE SUN IN THE MILKY WAY?

For us on Earth, the sun is precious and irreplaceable. Without its light and warmth, most life on Earth would not be possible. But in the galactic perspective, the sun is just one (rather ordinary) star out of 200 billion.

The sun orbits about 26,000 light-years from the black hole Sagittarius A*, roughly in the middle of the galactic disc. Travelling at the speed of 515,000 mph (828,000 kph), the sun takes 230 million years to complete a full orbit around the galactic center. That means the last time our planet was at the same exact place in the galaxy as it is today, it was dinosaurs who were awestruck by its star-studded vastness.

The sun sits near the edge of the Local Arm of the Milky Way, one of the two smaller spiral arms of the galaxy. In 2019, using data from the Gaia mission, astronomers found that the sun is essentially surfing a wave of interstellar gas that’s 9,000 light-years long, 400 light-years wide and undulates 500 light-years above and below the galactic disc.

Planets of the solar system do not orbit in the plane of the galaxy, but are tipped by about 63 degrees.

“It’s almost like we’re sailing through the galaxy sideways,” Merav Opher, an astrophysicist at George Mason University in Virginia, told Space.com.

HOW OLD IS THE MILKY WAY?

Astronomers believe the Milky Way is about 13.6 billion years old — only 200 million years younger than the universe.

The galaxy’s evolution began when clouds of gas and dust started collapsing, pushed together by gravity. First stars sprung up from the collapsed clouds, those that we see today in the globular clusters. The spherical halo emerged soon after, followed by the flat galactic disc. The galaxy started small and grew as the inescapable force of gravity pulled everything together. The galaxy’s evolution is, however, still shrouded in mystery.

A discipline called galactic archaeology is slowly unravelling some of the puzzles of the Milky Way’s life thanks to the Gaia mission, which released its first catalog of data in 2018.

Gaia measures the exact positions and distances of 1 billion stars, as well as their light spectra, which enables scientists to understand the stars’ composition and age. The position data allow astronomers to determine the speeds and directions in which the stars move in space. As things in space follow predictable trajectories, astronomers can reconstruct the paths of the stars billions of years into the past and future. Combining these reconstructed trajectories into one stellar movie captures the evolution of the galaxy over eons.

HOW DID THE MILKY WAY FORM?

About 50 dwarf galaxies orbit the Milky Way, destined to be devoured in the future.

Fascinating insights emerged from this movie, revealing how the galaxy grew from collisions between smaller galaxies over billions of years.

In 2018, a team of Dutch astronomers found a group of 30,000 stars moving in sync through the sun’s neighborhood in the opposite direction to the rest of the stars in the data set. The motion pattern matched what scientists had previously seen in computer simulations of galactic collisions.

These stars also differed in color and brightness, which suggested they came from a different galaxy.

Remnants of another, slightly younger, collision were spotted a year later. The Milky Way continues devouring smaller galaxies to this day. A galaxy called Sagittarius (not to be mistaken with the black hole) currently orbits close to the Milky Way and has likely smashed through its disc several times in the past 7 billion years. Using Gaia data, scientists found that these collisions triggered periods of intense star formation in the Milky Way and may even have something to do with the galaxy’s trademark spiral shape. The study suggests that our sun was born during one of those periods some 4.6 billion years ago.

THE FUTURE OF THE MILKY WAY RESEARCH

Since the beginning of its operations, the Gaia mission has provided three updates to its massive stellar catalog. Astronomers from all over the world continue analyzing the data in search of new patterns and revelations. In fact, Gaia data currently generates more research papers than even the famous Hubble Space Telescope. In a recent “space telescope tournament”, a jokey poll run by astronomers on Twitter, Gaia beat the veteran Hubble by five votes as the current darling of the astronomical community.

Gaia will continue charting the galaxy until at least 2022, and the catalog it has compiled will keep astronomers busy for decades to come.

Before Gaia, the largest dataset about positions and distances of stars in the Milky Way came from a mission called Hipparcos, after an ancient Greek astronomer who began charting the night sky 150 years before Christ. Hipparcos only saw about 100,000 of the brightest stars in the sun’s neighborhood, compared to Gaia’s one billion. The data was also less precise.

Even though Gaia sees less than 1% of stars in the galaxy, astronomers can expand its findings and model the behavior of the entire Milky Way.

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Todd

ADDITIONAL RESOURCES

Guide to our galaxy from the European Space Agency (ESA)
The anatomy of the Milky Way from ESA’s Gaia mission.
NASA’s Milky Way Galaxy overview
How does Gaia study the Milky Way? from ESA
Why was it so difficult to study the Milky Way before Gaia?

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Todd

This is the best article I’ve read on the James Webb Space Telescope. Very in-depth and covering a range of subjects pertaining to it.

https://www.quantamagazine.org/why-nasas-james-webb-space-telescope-matters-so-much-20211203/

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Rocket, Todd, Sean Robinson

Sean Robinson wrote:

For us on Earth, the sun is precious and irreplaceable.

This guy doesn’t spend a lot of time talking with actual human beings.  Mansplain much!

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Sean Robinson

China’s Yutu 2 rover spots cube-shaped ‘mystery hut’ on far side of the moon

It’s likely a large boulder excavated by an ancient lunar impact the proof we’ve been waiting for.

China’s Yutu 2 rover has spotted a mystery object on the horizon while working its way across Von Kármán crater on the far side of the moon.

Yutu 2 spotted a cube-shaped object on the horizon to the north and roughly 260 feet (80 meters) away in November during the mission’s 36th lunar day, according to a Yutu 2 diary published by Our Space, a Chinese language science outreach channel affiliated with the China National Space Administration (CNSA).

Our Space referred to the object as a “mystery hut” (神秘小屋/shenmi xiaowu), but this a placeholder name rather than an accurate description.

This zoomed-in image shows a closer look at a cube shape spotted by China’s Yutu 2 rover on the far side of the moon.

Team scientists have expressed a strong interest in the object and Yutu 2 is now expected to spend the next 2-3 lunar days (2-3 Earth months) traversing lunar regolith and avoiding craters to get a closer look, so updates can be expected.

A likely explanation for the shape would be a large boulder which has been excavated by an impact event.

The solar-powered Yutu 2 and Chang’e 4 lander made the first ever landing on the far side of the moon on Jan. 3, 2019, and the rover has been rolling through the 115-mile-wide (186 kilometers) Von Kármán crater ever since.

Chang’e 4, like its name suggests, is China’s fourth moon mission and second to deliver a rover on the moon. The Chang’e 1 and 2 missions were orbiters, with Chang’e 3 landing on the near side of the moon with the first Yutu rover. China has also launched the Chang’e 5 T1 test mission around the moon and the Chang’e 5 moon sample return mission.

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Todd

Massive planet 10 times bigger than Jupiter discovered orbiting pair of giant stars – NBCNews.com

“Until now, no planets had been spotted around a star more than three times as massive as the Sun,” wrote the European Southern Observatory.

The European Southern Observatory’s Very Large Telescope has recorded an image of a planet around the two-star system b Centauri.

Scientists have discovered a giant planet orbiting a massive pair of extremely hot stars, an environment previously thought too inhospitable for a planet to form in.

A research article published Wednesday in the science journal Nature said the discovery of the planet, named “b Centauri (AB)b” or “b Centauri b,” disproves a widely held belief among astronomers.

“Until now, no planets had been spotted around a star more than three times as massive as the Sun,” wrote the European Southern Observatory, which photographed the planet from its Very Large Telescope in the Chilean desert.

The study’s leader, Markus Janson, a professor of astronomy at Stockholm University, said “it completely changes the picture about massive stars as planet hosts.”

The “B-type” dual star, which sits at the center of a solar system in the Centaurus constellation, is extremely massive and hot. It emits large amounts of high-energy ultraviolet and X-ray radiation, which has “a strong impact on the surrounding gas that should work against planet formation,” the European Southern Observatory said.

“B-type stars are generally considered as quite destructive and dangerous environments, so it was believed that it should be exceedingly difficult to form large planets around them,” Janson said in a news release.

The discovery was described in July and formally published in Nature on Wednesday. Researchers said the “results show that planets can reside in much more massive stellar systems than what would be expected from extrapolation of previous results.”

The newly discovered b Centauri (AB)b is an exoplanet, a planet outside our own solar system, and it “is 10 times as massive as Jupiter, making it one of the most massive planets ever found,” the observatory wrote.

Co-author Gayathri Viswanath, a Ph.D. student at Stockholm University, said in the news release that it is “an alien world in an environment that is completely different from what we experience here on Earth and in our Solar System.”

“It’s a harsh environment, dominated by extreme radiation, where everything is on a gigantic scale: the stars are bigger, the planet is bigger, the distances are bigger,” Viswanath said.

The observatory wrote that the planet’s orbit is “one of the widest yet discovered,” 100 times greater than the distance between Jupiter and the sun. “This large distance from the central pair of stars could be key to the planet’s survival,” it said.

While the photograph published this month is the first of the planet since it has been identified, b Centauri (AB)b was imaged but unrecognized in previous telescope captures, researchers said.

Janson said in an email that the discovery has motivated him and his colleagues to expand on a survey called BEAST, which is examining 85 similar stars.

“We will be attempting to acquire more telescope time for an extended survey, and we are also scanning all the telescope archives after any individual high-mass stars that might have been observed in the past,” Janson wrote.

“I think in the field altogether there will be an increased search intensity toward high-mass stars, both for the purpose of detecting planets, but also for characterizing them, to find out what they are composed of and try to figure out more in detail how they might have formed,” he wrote.

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Todd

Largest collection of free-floating planets found in the Milky Way

https://phys.org/news/2021-12-largest-free-floating-planets-milky.html

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The 10 biggest space science stories of 2021

When will the sun explode?

Indestructible ‘Black Box’ will record our planet’s demise in minute detail

The disaster recorder aims to set us on a better path by watching our every move.

Here, a concept image of a futuristic monolith in the desert. This is not an artist’s conception of Earth’s black box.

I laughed out loud at that one. Immediately thought of @rocket

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Rocket, Todd

Space Calendar

Jan. 2-3: The Quadrantid meteor shower peaks.
Jan. 2: The new moon arrives at 1:33 p.m. EST (1833 GMT).
Jan. 4: Happy perihelion day! Earth is closest to the sun today.
Jan. 5: Conjunction of the moon and Jupiter. The waxing crescent moon will swing about 4.5 degrees to the south of Jupiter in the evening sky.
Jan. 7: Mercury reaches its greatest eastern elongation from the sun in its current evening apparition. The innermost planet will be shining brightly at magnitude -0.6. Catch the elusive planet above the western horizon shortly after sunset. It will reach its highest altitude in the evening sky on Jan. 11.

Jan. 17: The full moon of January, known as the Wolf Moon, arrives at 6:48 p.m. EST (2348 GMT).

Jan. 29: Conjunction of the moon and Mars. The waning crescent moon will pass just 2.4 degrees north of the Red Planet. Look for the pair in the dawn sky in the constellation Sagittarius.
Feb. 1: The new moon arrives at 12:46 a.m. EST (0546 GMT).
Feb. 12: Conjunction of Venus and Mars. The two planets will be about 6.5 degrees apart in the dawn sky. Look for the pair in the constellation Sagittarius.

Feb. 16: The full moon of February, known as the Snow Moon, arrives at 11:56 a.m. EST (1656 GMT).

Feb. 27: The moon, Mars and Venus will align in the early morning sky. Look for the trio in the constellation Sagittarius before sunrise.
March 2: The new moon arrives at 12:34 p.m. EST (1734 GMT).
March 12: Conjunction of Venus and Mars. The two planets will be about 4 degrees apart in the dawn sky. Look for the pair in the constellation Capricornus before sunrise.

March 18: The full moon of March, known as the Worm Moon, arrives at 3:18 a.m. EDT (0718 GMT).

March 20: Vernal equinox. Today marks the first day of spring in the Northern Hemisphere and the first day of fall in the Southern Hemisphere.

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Todd

Largest dark energy map could reveal the fate of the universe

Star trails are seen over the Nicholas U. Mayall 4-meter Telescope on Kitt Peak National Observatory near Tucson, Arizona.

A modified telescope in Arizona has produced an interim map, which is already the largest three-dimensional map of the universe ever — and the instrument is only about a tenth of the way through its five-year mission.

The Dark Energy Spectroscopic Instrument (DESI), a collaboration between Lawrence Berkeley National Laboratory in California and scientists around the world, was installed between 2015 and 2019 on the Mayall telescope at the Kitt Peak National Observatory in the Sonoran Desert, about 50 miles (88 kilometers) west of Tucson, and has been conducting a survey for less than a year.

Its purpose is to create an even larger 3D map of the universe, to yield a better understanding of the physics of dark energy, the mysterious force that is accelerating the expansion of the universe.

“There is a lot of beauty to it,” said Julien Guy, a physicist at Berkeley Lab who is working on the project. “In the distribution of the galaxies in the 3D map, there are huge clusters, filaments and voids.

“They’re the biggest structures of the universe,” he added. “But within them, you find an imprint of the very early universe and the history of its expansion since then.” The researchers hope that understanding the effects of dark energy could help them determine the ultimate fate of the universe.

The DESI team used a giant two-dimensional map of the universe released in January 2021 to prepare the instrument for the three-dimensional survey, which started a few weeks later.

The new 3D map pinpoints the locations of over 7.5 million galaxies, greatly exceeding the previous record of roughly 930,000 galaxies set by the Sloan Digital Sky Survey in 2008.

In this 3D scan of the universe, Earth is shown in the lower left, looking out the directions of the constellations Virgo, Serpens and Hercules to distances beyond 5 billion light-years. Each colored point represents a galaxy, which in turn is composed of 100 billion to 1 trillion stars. Gravity has clustered the galaxies into structures called the “cosmic web,” with dense clusters, filaments and voids.

Galaxy survey

DESI collects spectroscopic images of millions of galaxies spread out across about a third of the sky, according to a statement from Berkeley Lab.

By examining the color spectrum of the light from each galaxy, scientists can determine how much the light has been “redshifted” — that is, stretched toward the red end of the spectrum by a Doppler effect caused by the expansion of the universe. In general, the greater a galaxy’s redshift, the faster it is moving away and the farther it is from observers on Earth.

Our universe has been expanding since it began with the Big Bang about 13.8 billion years ago, and it is now much larger — at least 92 billion light-years across — than the farthest distances we can see.

Related: From Big Bang to present: Snapshots of our universe through time

Scientists with the DESI project hope their 3D map of the cosmos will reveal the “depth” of the sky and help them chart clusters and superclusters of galaxies, according to the statement. Because those structures carry echoes of their initial formation as physical ripples in the material of the infant cosmos, the researchers hope to use the data to determine the expansion history of the universe — and its ultimate fate.

“Our science goal is to measure the imprint of waves in the primordial plasma,” Guy said. “It’s astounding that we can actually detect the effect of these waves billions of years later, and so soon in our survey.”

Dark energy

Scientists used to think that the universe was expanding at a constant rate, or that the combined matter and energy in the universe might eventually cause that expansion to slow down. But observations of powerful stellar explosions called supernovas beginning late in the past century showed that the expansion is actually accelerating, so scientists coined the phrase “dark energy” to account for this unexpected phenomenon.

Calculations now suggest that dark energy makes up around 70% of the total energy in the observable universe. The effects of dark energy are now recognized as the “cosmological constant” that Albert Einstein included in his theory of general relativity; understanding dark energy has become a crucial scientific goal in recent decades, according to Smithsonian magazine.

It seems that more dark energy is created as the universe expands, which accelerates the expansion of the universe, according to the statement.

Ultimately, the effects of dark energy will determine the destiny of the universe — whether it expands forever, rips itself apart or collapses again in a type of reverse Big Bang.

DESI is now cataloging the redshifts of about 2.5 million galaxies every month. The team expects to complete the 3D survey map in 2026, by which time the telescope will have observed an estimated 35 million galaxies.

DESI scientists are presenting some early astrophysical results from the instrument this week at a webinar hosted by the Berkeley Lab, called CosmoPalooza.

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Todd

PLANET 9: WHY 2029 IS CRUCIAL FOR STUDYING THE SOLAR SYSTEM’S MOST CONTROVERSIAL ORB – Inverse.com

The mission could reveal more secrets of our Solar System.

OBJECT 90377 SEDNA — a distant trans-Neptunian object known best for its highly elliptical, 11,390-year-long orbit — is currently on its way towards perihelion (its closest approach to the Sun) in 2076.

After that, Sedna will swing out into deep space again and won’t be back for millennia, making this flyby a once-in-a-lifetime (or, once in ~113 lifetimes) opportunity to study an object from the far reaches of our solar system.

There are no missions to Sedna in the works just yet, but astronomers are beginning to plan for the possibility. The ideal launch date for such a mission is approaching fast, with two of the best launch windows coming up in 2029 and 2034.

Sedna was discovered in 2003 by Caltech astronomer Mike Brown and his team and was one of a series of potential dwarf planets (alongside similar-sized bodies like Haumea, Makemake, and Eris) whose discovery led to the demotion of Pluto in 2006.

As best we can tell from a distance, Sedna is about the same size as Ceres, the largest object in the asteroid belt, but its composition and origins are very different. Its chemical makeup suggests it may be covered in deep reddish organic compounds known as tholins, the same material seen on Pluto and other Kuiper belt objects.

Unlike Pluto, it is usually too cold for the methane abundant on its surface to evaporate and fall back as snow, though Sedna may briefly gain an atmosphere of nitrogen as it approaches the Sun.

What sets Sedna apart from the other known dwarf planet candidates is its enormous orbit, which takes it out towards the inner edge of the Oort cloud, the most distant region of the Solar System, where long-period comets lurk. There are several competing theories to explain how Sedna ended up in this position.

Perhaps the most high-profile theory is the possibility that a yet unknown ninth planet, perhaps 10 times the size of Earth, disrupted Sedna’s orbit and swept it and several other objects out into highly elongated orbits. Visiting Sedna probably won’t solve this particular mystery, but it will tell us a lot about the composition of these extreme trans-Neptunian objects.

The orbit of dwarf planet candidate 90377 Sedna (red) compared to Jupiter (orange), Saturn (yellow), Uranus (green), Neptune (blue), and Pluto (purple).

Reaching Sedna with a spacecraft won’t be a simple task. Even at its closest approach, Sedna will only come about 76AU from the Sun. For comparison, Neptune is about 30AU, and the Voyager missions, launched in 1977, are just now crossing 150AU and 125AU respectively. That means the time to launch is sooner, rather than later.

In planning a mission to Sedna, the Voyager spacecraft are not bad places to look for inspiration. They famously took advantage of a lucky alignment of planets to take a grand tour of the outer Solar System, stealing energy from Jupiter to pick up speed and reach their more distant targets.

Similar gravity assists will be required to make the trip to Sedna manageable. A team of scientists led by Vladislav Zubko from the Space Research Institute of the Russian Academy of Sciences recently modeled a series of possible trajectories to Sedna, favoring a 2029 launch date as the most feasible option.

The 2029 trajectory, they determined, would take the spacecraft to Venus first, then back to Earth (twice), before passing Jupiter on the way to Sedna, with flight times as short as 20 years but more optimally in the 30-year range. The longer flight time would increase the altitude of the spacecraft over Jupiter during the gravity assist, reducing the time spent exposed to the gas giant’s harmful radiation.

A 30-year flight plan would also mean passing by Sedna more slowly, providing more time to gather data on the object. Choosing this option would give the spacecraft a relative velocity of 13.70 km/s (29,000 mph) as it passed Sedna, comparable to the speed at which New Horizons approached Pluto in 2015.

As a bonus, this trajectory would also take the spacecraft past a 145 km (90 miles) diameter asteroid named Massalia, providing the team with an additional scientific target to study, as well as a chance to test the spacecraft’s systems.

A second trajectory proposed by the team would consist of a 2034 launch and would provide a similar additional flyby, this time of the metallic asteroid 16 Psyche.

At the moment, it’s unclear whether a mission to Sedna will make it to the launch pad with all the competing options available to mission planners in the coming decade. But as it’s our only chance in the next 11,000 years, the idea is sure to be given due diligence.

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Todd

The Nearest Stars to Earth (Infographic)

Exploring the stars closest to our home planet.

The nearest stars, their distances in light-years, spectral types and known planets.

Stars speckle the expanse of our ever-expanding universe. While our closest star is the sun that we orbit in our little corner of the cosmos, we can peer out to see what stellar neighbors live nearby.

The nearest stars to Earth are three stars that lie about 4.37 light-years away in the Alpha Centauri triple-star system. The closest of these stars, Proxima Centauri, is just about 4.24 light-years away. (for reference, one light-year is approximately equivalent to 5.88 trillion miles (9.46 trillion kilometers)).

Suffice to say, “close” in space is far different from our Earthly definition.

Of all the stars closer than 15 light-years, only two are the same type as our sun: a G-type main-sequence star. G-type stars like our sun, also called yellow dwarf stars, typically have about 0.9 to 1.1 solar masses with surface temperatures that can range from about 9,080 degrees Fahrenheit (5,026 degrees Celsius) to 10,340 degrees F (5,726 degrees C).

The only two other G-type stars in our neighborhood are Alpha Centauri A and Tau Ceti. The majority of nearby stars are M-type stars, also known as red dwarfs, the most common stars in the universe.

Only nine of the stars in this area are bright enough to be seen by the naked human eye from Earth. These bright stars include Alpha Centauri A and B, Sirius A, Epsilon Eridani, Procyon, 61 Cygni A and B, Epsilon Indi A and Tau Ceti.

Barnard’s Star, a red dwarf 5.96 light-years away, has the largest proper motion of any known star. This means that Barnard’s Star moves rapidly against the background of more distant stars, at a rate of 10.3 seconds of arc per Earth year.

Sirius A is the brightest star in Earth’s night sky, due to its intrinsic brightness and its proximity to us. Sirius B, a white dwarf star, is smaller than Earth but it has a mass 98 percent that of our sun.

In late 2012, astronomers discovered that Tau Ceti may host five planets including one within the star’s habitable zone. Tau Ceti is the nearest single G-type star like our sun (although the Alpha Centauri triple-star system also hosts a G-type star and is much closer).

The masses of Tau Ceti’s planets range from between two and six times the mass of Earth.

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[Sean Robinson]

There Are 40,000,000,000,000,000,000+ Black Holes in the Observable Universe, Says New Estimate – Gizmodo.com

The team of astrophysicists found that 1% of ordinary matter may be stored away in the lightless spheres.

An artist’s conception of a supermassive black hole spewing a relativistic jet.

A team of astrophysicists has calculated the number of stellar-mass black holes in the observable universe to be 40 quintillion, accounting for 1% of the total ordinary matter in the universe.

The researchers focus on stellar-mass black holes, the smallest-known variety, but note that their calculations could help address the longstanding mystery of how supermassive black holes proliferated. Their research is published in the Astrophysical Journal Letters.

For a long time, black holes were only theorized to exist and had never been observed—as their name suggests, they don’t let light escape their gravitational pull. But astronomers have figured out that black holes are at the center of large concentrations of light-emitting matter (our own Milky Way features a supermassive black hole at its center). More recently, black holes mergers have been detectable thanks to gravitational wave detectors like the LIGO-Virgo Collaboration.

But counting all the black holes in the observable universe, which stretches some 90 billion light-years across, is a daunting task. To get to the 40 quintillion sum (that’s 40 billion billions, or 40,000,000,000,000,000,000) the research team coupled a new star evolution code called SEVN and with data on the metallicity, star formation rates, and stellar sizes in known galaxies.

“The innovative character of this work is in the coupling of a detailed model of stellar and binary evolution with advanced recipes for star formation and metal enrichment in individual galaxies,” said Alex Sicilia, an astrophysicist at SISSA in Italy and the paper’s lead author, in an institute release. “This is one of the first, and one of the most robust, ab initio computation of the stellar black hole mass function across cosmic history.”

An illustration of the observable universe, with the Sun at center, and the cosmic microwave background surrounding it.

The research is the first in a series of works that is attempting to model black hole masses, from star-sized ones up to supermassive black holes. Stellar-mass black holes are the smallest-known of the bunch, generally weighing in at few to a few hundred times the mass of the Sun. Intermediate black holes are notoriously absent from the observational record, but supermassive black holes reside at the center of most galaxies and accrete matter around them, pulling stars, planets, and gases close with their ridiculous gravitational might.

In the paper, the researchers also investigated how black holes of varying sizes might form. Stellar-mass black holes arise from the collapsed cores of dead stars, but the origins of supermassive black holes are more of a mystery. Lumen Boco, also an astrophysicist at SISSA and co-author of the paper, said in the same release that the team’s calculations “can constitute a starting point to investigate the origin of ‘heavy seeds’, that we will pursue in a forthcoming paper.”

The new study doesn’t address so-called primordial black holes, hypothetical objects left over from the beginning of the universe that could be much, much smaller than any known black holes. There’s no evidence that these actually exist, but some physicists have suggested them as a potential solution to the mystery of dark matter. One team actually proposed that a bowling ball-size black hole could be Planet Nine, a theoretical body in the outer solar system affecting the orbits of distant objects.

• This reply was modified 2 years, 11 months ago by Sean Robinson.

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Todd

Sean Robinson wrote:

An artist’s conception of a supermassive black hole spewing a relativistic jet.

You know with all these artist’s conceptions you think that these guys could be more creative when naming stars (see previous post)

How far is Earth from the sun?

Or: what is an astronomical unit?

The average distance between the Earth and the sun is an astronomical unit.

Earth travels around the sun in an orbit that is slightly oval-shaped, known as an ellipse. Therefore, the planet’s distance from the sun changes throughout the year.

However, the average distance from Earth to the sun is about 93 million miles (150 million kilometers). Scientists also call this distance one astronomical unit (AU).

The universe is a big place, and sometimes researchers use the astronomical units to communicate how far celestial objects are separated from one another. For example, Jupiter orbits about 5 AU from the sun.

EARTH’S DISTANCE FROM THE SUN CHANGES

In early January, Earth reaches its closest position to the star. Astronomers call this point perihelion, and at this time Earth is about 91.4 million miles (147.1 million km) away from the sun, according to NASA.

Keep in mind that Earth’s distance from the sun does not determine the seasons we experience; the seasons are determined by the tilt of the planet’s axis. This is why the season occurring in Earth’s Southern Hemisphere is always in opposition to the season in the Northern Hemisphere.

Half a year after perihelion, Earth reaches its farthest distance from the star, which is called aphelion. At that moment, the planet is approximately 94.5 million miles (152.1 million km) from the sun. Aphelion occurs in early July.

Perihelion and aphelion average out to about 93 million miles (150 million km).

A NEW, MORE PRECISE ASTRONOMICAL UNIT

The International Astronomical Union (IAU) is an international nonprofit organization that is tasked with, among many other things, defining astronomical constants. In August 2012, IAU members voted to approve a more exact measurement of 1 AU.

An astronomical unit is now more precisely defined as “a conventional unit of length equal to 149,597,870,700 meters exactly.” That translates to roughly 92,955,807 miles (149,597,871 km).

Why was this decision necessary? The equation that had previously determined the value of an AU depended on information including the mass of the sun. But that value changes because the star is constantly transforming its mass into energy, according to 2012 reporting by Nature.

Einstein’s theory of general relativity also throws a wrench in the evaluation of an AU because it argues that space-time is relative depending on the observer’s location in the solar system. This complication made it difficult for planetary scientists working on models of the solar system.

The IAU’s recently-adopted value is measured using the speed of light in the vacuum of space, which is constant.

THE ORIGINAL CALCULATION

The first-known person to measure the distance to the sun was the Greek astronomer Aristarchus of Samos, who lived from about 310 B.C. to 230 B.C. He used the phases of the moon to measure the sizes and distances of the sun and moon.

He postulated that when the half moon appears in Earth’s sky, the center of our planet and the center of the moon create a line in space that forms a 90 degree angle with another line that could be drawn through space from the moon’s center all the way to the sun’s center. Using trigonometry, Aristarchus could determine the hypotenuse of a triangle based on those two imaginary lines. The value of the hypotenuse would provide the distance between the sun and the Earth.

Although imprecise, Aristarchus provided a simple understanding of the sizes and distances of the three bodies, which led him to conclude that the Earth goes around the sun, about 1,700 years before Nicolaus Copernicus proposed his heliocentric model of the solar system.

In 1653, astronomer Christiaan Huygens calculated the distance from Earth to the sun. Much like Aristarchus, he used the phases of Venus to find the angles in a Venus-Earth-sun triangle. His more precise measurements for what exactly constitutes an AU were possible thanks to the existence of the telescope.

Guessing (correctly, by chance) the size of Venus, Huygens was able to determine the distance from Venus to Earth. Knowing that distance, plus the angles made by the triangle, he was able to measure the distance from Earth to the sun. However, because Huygens’ method was partly guesswork and not completely scientifically grounded, he usually doesn’t get the credit.

In 1672, Giovanni Cassini used a method involving parallax, or angular difference, to find the distance to Mars and at the same time figured out the distance to the sun. He sent a colleague, Jean Richer, to Cayenne, French Guiana (located just northwest of the modern-day Guiana Space Center near Kourou) while he stayed in Paris. At the same time, they both took measurements of the position of Mars relative to background stars, and triangulated those measurements with the known distance between Paris and French Guiana. Once they had the distance to Mars, they could also calculate the distance from Earth to the sun. Since his methods were more scientific, Cassini usually gets the credit.

These techniques are also why astronomers continue to use the distance from Earth to the sun as a scale for interpreting the solar system.

“Expressing distances in the astronomical unit allowed astronomers to overcome the difficulty of measuring distances in some physical unit,” astronomer Nicole Capitaine of Paris University told Space.com. “Such a practice was useful for many years, because astronomers were not able to make distance measurements in the solar system as precisely as they could measure angles.”

ACROSS THE SOLAR SYSTEM

Artists rendering of the Kuiper Belt and Oort Cloud.

The sun is at the heart of the solar system. All of the bodies in the solar system — planets, asteroids, comets, etc. — revolve around it at various distances.

Mercury, the planet closest to the sun, gets as close as 29 million miles (47 million km) in its elliptical orbit, while objects in the Oort Cloud, the solar system’s icy shell, are thought to lie as far as 9.3 trillion miles (15 trillion km).

Everything else falls in between. Jupiter, for example, is 5.2 AU from the sun. Neptune is 30.07 AU from the sun.

The distance to the nearest star, Proxima Centauri, is about 268,770 AU, according to NASA. However, to measure longer distances, astronomers use light-years, or the distance that light travels in a single Earth-year, which is equal to 63,239 AU. So Proxima Centauri is about 4.25 light-years away.

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What’s next for NASA’s James Webb Space Telescope after its nearly million-mile journey to destination

Science operations are expected to begin in late June or early July.

NASA’s James Webb Space Telescope, seen here in an artist’s illustration, is at its final destination nearly 1 million miles from Earth.

NASA’s James Webb Space Telescope has reached its deep-space destination, but it’ll be a while yet before the $10 billion observatory starts its science work.

On Monday (Jan. 24), Webb slipped into orbit around the Earth-sun Lagrange Point 2, a gravitationally stable spot in space about 930,000 miles (1.5 million kilometers) from our planet. The arrival ended a month-long journey for the highly anticipated observatory, but there are still a lot of boxes to tick before Webb gets down to business.

“We expect the first science images from JWST to come back in about five months,” Amber Straughn, the deputy project scientist for Webb science communications, said during a webcast Webb event on Monday.

“So, be getting excited, getting ready for those to come back later on this summer,” added Straughn, who’s based at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

The Webb team will be working on two major tasks over the next five months. The first is precisely aligning the 18 hexagonal segments that make up Webb’s 21.3-foot-wide (6.5 meters) primary mirror, an exacting process that will take about three months.

The resulting light-collecting surface must be nearly perfect for Webb to function properly. If the finished primary mirror were the size of the continental United States, the biggest bump on it would be just an inch or two high, Straughn said.

Mirror-segment alignment is expected to begin next week, after Webb’s optics and associated instruments get cold enough to allow such work to proceed. (Webb is optimized to view the cosmos in infrared light — wavelengths we feel as heat — so everything on it is designed to operate at very cold temperatures. The slightest infrared emissions coming from the scope could drown out the faint heat signals it’s after.)

To guide mirror alignment, the Webb team will focus each of the 18 primary mirror segments on a bright, distant star. And they’ve already chosen this target — a sunlike star known as HD 84406 that’s part of the constellation Ursa Major (The Great Bear).

“It’s just near the bowl of the Big Dipper,” Lee Feinberg, the Webb optical telescope element manager at NASA Goddard, said in a different webcast event on Monday. “You can’t quite see it with your naked eye, but I’m told you can see it with binoculars.”

After the primary mirror is set up, the Webb team will align it with the 2.4-foot-wide (0.74 m) secondary mirror, which is so named because it’s the second surface that photons will hit on their way into the observatory’s four science instruments. That milestone will mark the end of the major mirror work, team members said.

But Webb’s instruments will still need to be checked out and calibrated, also a time-consuming activity. The team expects to have everything done, and therefore be ready to open the telescope’s super-sharp eyes in earnest, by late June or early July.

And the observatory will hit the ground running at that point. The first year of science observations has already been planned out, Straughn said.

“We will be looking at things in the universe ranging from objects within our own solar system, all the way out to searching for the very first galaxies to be born after the Big Bang and everything in time and space in between,” she said. “It’s going to be awesome.”

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Astronomers detect powerful cosmic object unlike anything they’ve seen before

It blinks too fast to be a supernova and too slow to be a pulsar. So what in the cosmos is it?

An artist’s impression of a slow spinning magnetar that might be the source of the mysterious signal.

Astronomers have discovered a mysterious, flickering object in our galaxy, the Milky Way, that belches enormous amounts of energy toward Earth three times an hour.

This strangely powerful object — located about 4,000 light-years from the sun — is unlike any cosmic structure ever observed, researchers wrote in a statement.

The object in question — named GLEAM-X J162759.5-523504.3 (but let’s call it GLEAM for short) — appeared out of nowhere on a recent radio wave survey of the Milky Way. According to the researchers, GLEAM brightened rapidly over the course of about 60 seconds, briefly becoming one of the brightest objects in the entire sky, then suddenly disappeared into darkness again. About 20 minutes later, the object reappeared — steadily glowing to peak brightness once again, before dimming back to nothing a minute later.

Objects like these, which appear and disappear before our telescope lenses, are known as transients. Typically, transients represent either a dying star, a supernova, or the bizarre, rapidly-spinning corpse of an already-dead star, also known as a neutron star. However, neither of those standard explanations quite fit with the behavior of this newfound object, researchers wrote in the new study.

It’s possible that the mysterious GLEAM is evidence of a new type of stellar object that has only been theorized until now — or even one that astronomers haven’t even dreamt up.

“This object was appearing and disappearing over a few hours during our observations. That was completely unexpected,” lead study author Natasha Hurley-Walker, a radio astronomer at Curtin University in Bentley, Australia, said in the statement. “It was kind of spooky for an astronomer because there’s nothing known in the sky that does that.”

The position of the mysterious flashing object in the Milky Way.

Last light of a dying star

Transients typically come in two varieties. “Slow transients” can appear over the course of a few days, then disappear after several months. These include supernovas — which blaze brightly as dying stars shed their outer atmospheres in violent explosions, then gradually dim as the stellar leftovers drop in temperature.

Then, there are “fast transients,” which flicker on and off every few milliseconds. These include objects like pulsars — neutron stars which rotate incredibly rapidly while flashing with bright radio emissions generated by the dead star’s magnetic field.

The authors of the new study were looking for transients like these using the Murchison Widefield Array (MWA) radio telescope in the Australian outback, when they discovered GLEAM. The on-off blinking is too fast to be a supernova and too slow to be a pulsar; GLEAM’s one-minute-long brightening pattern defies explanation, the researchers said.

An analysis of the object showed that it was incredibly bright but smaller than Earth’s sun. GLEAM’s radio emissions were also highly-polarized (that is, their light waves only vibrate on a single plane), suggesting they were generated by an extremely powerful magnetic field, according to the study authors.

These characteristics match a type of theoretical object known as an “ultra-long period magnetar,” which is essentially a highly magnetized neutron star that rotates incredibly slowly. While predicted to exist, this rare class of object has never been observed in space before, the researchers said.

“Nobody expected to directly detect one like this because we didn’t expect them to be so bright,” Hurley-Walker said. “Somehow it’s converting magnetic energy to radio waves much more effectively than anything we’ve seen before.”

There may be other explanations for the mysterious GLEAM also, the researchers added. It could be a rare type of white dwarf star (the shriveled husk of a dead star that wasn’t massive enough to collapse into a neutron star), which can very rarely emit radio emissions by sucking in material from a binary companion star. Such a star might appear to pulse like GLEAM, if it rotated at exactly the right speed, the team said.

Further observations in other bands of the electromagnetic spectrum are needed to solve this stellar mystery. Now that GLEAM has been detected, the researchers are also digging into archival observations from the MWA to see if any similar objects have ever turned up.

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Earth has an extra companion, a Trojan asteroid that will hang around for 4,000 years

This is the second Earth Trojan asteroid ever spotted and the largest of its kind ever seen.

In 2020, astronomers thought they’d found something incredible: the second so-called Earth Trojan asteroid ever seen. Now, a new team of researchers has confirmed that it’s real.

Trojan asteroids are small space rocks that share their orbit with a planet, circling whatever host star that planet does in a stable orbit. While we have spotted Trojan asteroids around other planets in our solar system and others, until now only one of these objects, called 2010 TK7, has been confirmed to orbit along the same path as Earth. In a new study, researchers confirmed that an asteroid spotted in 2020, called 2020 XL5, is the second object of its kind, called an Earth Trojan asteroid. Think of it as an extra companion to Earth, albeit a very tiny one.

“The discovery of 2020 XL5 as an Earth Trojan, confirms that 2010 TK7 is not a rare exception and that there are probably more,” study lead author Toni Santana-Ros, a researcher at the University of Alicante and the Institute of Cosmos Sciences (ICCUB) at the University of Barcelona (IEEC-UB), told Space.com. “This encourages us to keep enhancing our survey strategies to find, if exists, the first primordial Earth Trojan.”

This visualization shows the Earth-sun Lagrange points.

In December 2020, 2020 XL5 was spotted by astronomers with the Pan-STARRS 1 survey telescope in Hawaii and added to the International Astronomical Union’s Minor Planet Center database. Amateur astronomer Tony Dunn went on to calculate the object’s trajectory using NASA’s publicly-available JPL-Horizon’s software and found that it orbits L4, the fourth Earth-sun Lagrange point, a gravitationally balanced region around our planet and star. 2010 TK7, the first-confirmed Earth Trojan asteroid is also at L4.

“Preliminary results showed it was in a trojan orbit around our Lagrangian point L4,” Dunn told Space.com. “Its orbit was quite uncertain at the time so I did a more careful analysis, simulating 100 clones with similar orbits. Every clone demonstrated trojan behavior as well.”

But at the time, 2020 XL5’s orbit around the sun wasn’t fully understood, so it wasn’t yet certain whether the object was just a nearby space rock crossing Earth’s orbit or if it could be a real Earth Trojan asteroid.

To confirm whether or not it is an Earth Trojan asteroid, a team led by Santana-Ros observed the object with the SOAR (Southern Astrophysical Research) Telescope in Chile along with the Lowell Discovery Telescope in Arizona and the European Space Agency’s Optical Ground Station in Tenerife in the Canary Islands.

“These were very challenging observations, requiring the telescope to track correctly at its lowest elevation limit, as the object was very low on the western horizon at dawn,” co-author Cesar Briceño, a researcher at the National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory (NOIRLab), said in a statement.

Santana-Ros echoed how difficult it is to make these observations from Earth. It “is a pain for astronomers to point to the L4 and L5 points of the sun-Earth system while being on our planet! Any asteroid orbiting around these points will only be visible during a short time window close to twilight, at very low elevations above the horizon,” Santana-Ros told Space.com.

This visualization shows the Earth Trojan asteroid 2020 XL5.

To bolster their observations, the team also factored in archival data from SOAR to try and fully understand the object and its orbit. In total, the team was using about a decade’s worth of observations and data, according to the statement from NOIRLab.

The team concluded that, as it was initially suspected, 2020 XL5 is an Earth Trojan asteroid. They also found that the object is also likely a C-type asteroid, the most common asteroid type in the solar system that is high in carbon and dark.

“SOAR’s data allowed us to make a first photometric analysis of the object, revealing that 2020 XL5 is likely a C-type asteroid,” Santana-Ros said in the same statement. The study also revealed that this object is much larger than the first Earth Trojan asteroid found. 2020 XL5 measures about 0.73 miles (1.2 kilometers) across, almost three times longer than 2010 TK7 which stretches just about 0.25 miles (0.4 km) wide.

The team also found that 2020 XL5 won’t be an Earth Trojan asteroid forever. While it will stay in its current position for about 4,000 years, it will eventually escape its gravity-bound location, according to the statement.

“We are fully sure that 2020 XL5 will remain librating around L4 for at least 3,500 more years,” Santana-Ros told Space.com.

Briceño noted in the statement that this discovery could be followed by even more and that, potentially, the future could see humans stepping foot onto these types of asteroids.

“If we are able to discover more Earth Trojans, and if some of them can have orbits with lower inclinations, they might become cheaper to reach than our Moon,” Briceño said. “So they might become ideal bases for an advanced exploration of the solar system, or they could even be a source of resources.”

But whether or not we ever send humans to walk on them, NASA did launch the robotic Lucy asteroid mission in 2021 to study Jupiter’s Trojan asteroids and studying them can help us to better understand the universe at-large.

Trojan asteroids like XL5 “can provide us information about the formation of its host planet and, in turn, keys to better understand the evolution of the Solar System by adding constraints to its evolution models,” Santana-Ros told Space.com. “We have studied the primordial Jupiter Trojans for several years and we will soon have the opportunity to investigate them with in situ observations taken by NASA’s space mission Lucy.”

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Life-enabling moons can probably only form around small planets, study finds

The moon helps Earth keep life going.

The moon is a little more than one quarter the size of Earth. The Deep Space Climate Observatory satellite captured the moon and Earth together as the orbit of the satellite crosses the orbital plane of the moon.

Earth’s moon is large for the planet’s size, and many astronomers have long believed that this fact has helped make Earth a habitable world. And a new study has now found that our planet was just the right size to form such a large, life-enabling moon.

The study, by researchers from the University of Rochester in New York, found that rocky planets with a diameter more than 1.6 times that of Earth and icy planets with a diameter more than 1.3 times that of Earth likely can’t create moons that would have those life-enabling effects on them.

Earth’s moon has a radius larger than a quarter of Earth’s radius. That’s a much larger ratio than that of any other moon in our solar system and its host planet. Thanks to its large size compared to the planet, the moon controls the length of Earth’s day and governs ocean tides. The moon also stabilizes Earth’s axis of rotation, which in turn stabilizes its mild climate, which is favorable for life.

The moon, scientists believe, was born from a cataclysmic collision of a nascent Earth with a Mars-size world known as Theia. This impact stirred up a huge amount of material, part of which turned into vapor in the heat generated by the impact. For some time, this material circled Earth in a disk similar to the ring system of Saturn. The material in this disk, scientists believe, gradually gave rise to smaller moonlets, which subsequently merged to form one large moon.

So why can’t larger planets achieve the same end result? The new study, based on computer modelling, found that if larger planets collide, the energy of the impact is such that all of the ejected material vaporizes rather than part of it. And that makes a difference.

The large amount of vapor around the planet creates drag, which gradually slows down the moonlets as they orbit the planet, making them crash onto its surface, the study found.

“Our impact simulations show that terrestrial and icy planets that are larger than 1.3−1.6 [the radius of Earth] produce entirely vapor disks, which fail to form a fractionally large moon,” the scientists said in the study. “Our model supports the moon-formation models that produce vapor-poor disks and rocky and icy exoplanets whose radii are smaller than 1.6 [the radius of Earth] are ideal candidates for hosting fractionally large exomoons.”

The findings might help astronomers fine-tune their search for potentially habitable planets. They simply have to focus on those that can have a large moon compared to their size.

“By understanding moon formations, we have a better constraint on what to look for when searching for Earth-like planets,” study lead author Miki Nakajima, an assistant professor of earth and environmental sciences at the University of Rochester, said in a statement. “We expect that exomoons [moons orbiting planets outside our solar system] should be everywhere, but so far we haven’t confirmed any. Our constraints will be helpful for future observations.”

Nearly 5,000 exoplanets have been discovered since the detection of the first couple in 1992. None of these planets so far has been proven to have a moon,although scientists have found a few candidates.

But Nakajima suggests that the reason for this exomoon absence might be due simply to the size of the planets studied.

“The exoplanet search has typically been focused on planets larger than six Earth masses,” she said. “We are proposing that instead we should look at smaller planets because they are probably better candidates to host fractionally large moons.”

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ASTONISHING RADIO VIEW OF THE MILKY WAY’S HEART – Skyandtelescope.org

A new radio survey reveals a complex and chaotic galactic center teeming with supernova remnants, star-forming regions, and mysterious filaments.

The South African Radio Astronomy Observatory (SARAO) has released a series of captivating images: A mysterious dreamscape, painted in intricate brush strokes by the universe itself, depicts the chaotic heart of the Milky Way.

Unaffected by the large quantities of dust that obscure the central galactic region, radio waves reveal a scene of striking complexity produced by the interplaying effects of star formation, high density of cosmic rays, and the foreboding supermassive black hole known as Sagittarius A*.

“I am in awe every single time I look at the images,” says Isabella Rammala, a graduate student at Rhodes University in South Africa, who has been working on the project. “It is just amazing how many details MeerKAT could capture.”

Astronomers constructed the image using the sensitive MeerKAT radio telescope, an array of 64 antennas spread over a diameter of 8 kilometers (5 miles) in the Northern Cape province of South Africa. The telescope observed a region that covers an area 30 times that of the full Moon for 215 hours. The team described the survey and its publicly released products in a study to appear in The Astrophysical Journal.

RADIO FILAMENTS

One of the striking features in the image are numerous wispy tendrils known as radio filaments. Discovered in the early 1980s, the filaments can extend up to 150 light-years in length and appear highly organized: some come in pairs and others in clusters. Even though an air of mystery still surrounds the filaments, scientists do have ideas that could explain their origin.

One idea is that energetic particles, or cosmic rays, stream from our galaxy’s center, dragging with them the ambient magnetic field, compress it, and illuminate it. According to Farhad Yusef-Zadeh (Northwestern University), who discovered the radio filaments, the mechanism is not entirely understood. Still, it’s probably similar to the processes encountered in the solar wind.

“One thing that is a puzzle now is how you inject the cosmic-ray particles in the first place,” says Yusef-Zadeh. He led a study of cosmic filaments found in the MeerKAT image that will appear in The Astrophysical Journal Letters (preprint available here). His team found that the past activity of Sagittarius A* is more likely to have accelerated the particles. A competing explanation, a series of supernova explosions, is less probable.

The new image reveals nearly a thousand filaments, about 10 times more than previously discovered. “It is not just the number,” says Yusef-Zadeh. “We see a wide range of different sizes, the morphology is different, clustering is different.” For the first time, the numbers allow statistical studies of the filaments’ characteristics, hopefully leading to a better understanding of how they cluster as well as the peculiarly regular spacing between filaments within clusters.

MILKY WAY’S TREASURE TROVE

Apart from the filaments, the center of our galaxy hosts several notable radio-emitting structures. Two vast radio bubbles emanating from the galactic center, reaching above and below Milky Way’s disk, suggest that Sagittarius A* was quite active a few million years ago. In addition, the central region is home to clusters of young, massive stars like the Arches and Quintuplet, many puffy remnants of supernova explosions, and shells of ionized gas surrounding massive stars. Many of these objects were already known, but the team, which is now busily cataloging all the objects in the image, has already reported several new sources.

“There is quite a lot of compact objects there,” says Rammala. “My main interest is identifying those that may be potential pulsar candidates.” Due to the crowding of stars, dust and gas, it isn’t easy to find these spinning neutron stars in the galactic center. Yet, astronomers are eagerly searching for them. Among other applications, pulsars could explain why we observe an excess of gamma-rays in the galactic center.

The MeerKAT radio telescope is a precursor to the Square Kilometer Array, which will be the largest radio telescope in the world. South Africa and Australia will host its thousands of dishes and up to a million low-frequency antennas. Once the array is built, it will undoubtedly reexamine the lush neighborhood of the galactic center. But for now, the astronomers’ focus is the chaotic panorama of the MeerKAT image.

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Exoplanet evolution? Mini-Neptunes may shed their atmospheres and become super-Earths – Space.com

Two new studies point to peculiar possibilities for planetary evolution.

An artist’s Illustration of the mini-Neptune TOI 560.01, located 103 light-years away in the Hydra constellation. This exoplanet might be turning into a rocky super-Earth as its parent star bombards it with radiation.

New research suggests that stellar radiation is stripping away the “fluffy” atmospheres of exoplanets slightly smaller than Neptune, leaving behind their rocky cores and transforming them into worlds more closely resembling Earth.

In the 1990s, astronomers confirmed the existence of planets outside the solar system. Known as exoplanets, they are one of the most fascinating subjects of modern astronomy. Spacecraft such as NASA’s pioneering Kepler observatory and Transiting Exoplanet Survey Satellite (TESS) have scanned the skies searching for periodic dips in the brightness of nearby stars. This blinking is a sign that a star is hosting a planet, which has crossed the face of the star and temporarily blocked its light.

Now that astronomers have collected thousands of exoplanet signatures, they are getting a better idea about the range of planetary sizes. One useful way astronomers have been labeling their findings is by comparing these worlds to the familiar planets living in our cosmic backyard; existing exoplanet categories include “super-Earths” and “mini-Neptunes.”

Two new studies point to peculiar possibilities for planetary evolution, one of the key motivating factors behind exoplanet research.

Some exoplanets detected by astronomers are small, rocky worlds like Mars, and others are large gaseous planets such as Saturn and Jupiter. But researchers have also found worlds with no close analogs in our own solar system. For example, they’ve discovered exoplanets that are between the size of Earth and Neptune, which is about 3.9 times wider than our planet.

It turns out that these mini-Neptunes might be shedding their “fluffy” outermost shells and shrinking into super-Earths, according to the new research. This instability and transition may explain why it is relatively rare to detect exoplanets that are between the size of Neptune and Earth.

“A planet in the size-gap would have enough atmosphere to puff up its radius, making it intercept more stellar radiation and thereby enabling fast mass loss,” Michael Zhang, lead author of both studies and a graduate student at the California Institute of Technology (Caltech) in Pasadena, said in a Feb. 3 statement describing the papers. “But the atmosphere is thin enough that it gets lost quickly. This is why a planet wouldn’t stay in the gap for long.”

An illustration of the exoplanet system TOI 270, which was not the subject of the research by Michael Zhang and colleagues. However, this image depicts a star orbited by one super-Earth (the innermost planet) and two mini-Neptunes (the outermost, blue-colored planets).

According to Zhang, this process has never been caught until now. But astronomers have suspected for some time that small mini-Neptunes have evaporating atmospheres.

The researchers used the Hubble Space Telescope and the W.M. Keck Observatory in Hawaii to observe four mini-Neptunes. They noticed that two of their subjects — one called HD 63433c located 73 light-years away from Earth, and another called TOI 560.01 found 103 light-years away — had fast-moving gas in their atmospheres.

“The speed of the gases provides the evidence that the atmospheres are escaping,” said Zhang. “The observed helium around TOI 560.01 is moving as fast as 20 kilometers [12.4 miles] per second, while the hydrogen around HD 63433c is moving as fast as 50 kilometers [31.1 miles] per second.”

“The gravity of these mini-Neptunes is not strong enough to hold on to such fast-moving gas,” Zhang added. “The extent of the outflows around the planets also indicates escaping atmospheres; the cocoon of gas around TOI 560.01 is at least 3.5 times as large as the radius of the planet, and the cocoon around HD 63433c is at least 12 times the radius of the planet.”

Zhang and his team aren’t ruling out other possible scenarios. Maybe super-Earths never had a thick blanket of gas to shed in the first place, for instance.

“As exoplanet scientists, we’ve learned to expect the unexpected,” Heather Knutson, a planetary scientist at Caltech and Zhang’s advisor, said in the statement. “These exotic worlds are constantly surprising us with new physics that goes beyond what we observe in our solar system.”

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Todd

Sean Robinson wrote:

the robotic Lucy asteroid mission in 2021 to study Jupiter’s Trojan

it sounds like the plot for a porn flick

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NASA asteroid detector ‘looks up’ to scan entire sky every 24 hours

The new upgrade enables the system to scan the entire night sky in 24 hours.

Very large space rocks that fly within 4.6 million miles (7.5 million kilometers) of Earth’s solar orbit are known as potentially hazardous asteroids.

NASA’s asteroid monitoring system has been upgraded so that it can scan the entire night sky once every 24 hours for potentially hazardous space rocks that are heading our way.

The Asteroid Terrestrial-impact Last Alert System (ATLAS) is essential for tracking of asteroids and debris that could be on a collision course with Earth, and it is operated from the Institute of Astronomy at the University of Hawaii. ATLAS began as an array of just two telescopes in Hawaii, but it has now expanded to include two more telescopes in the Southern Hemisphere — giving it a complete view of the sky.

The new telescopes in the array are located in Chile and South Africa and, along with the two original Hawaiian telescopes, can image a chunk of the night sky 100 times larger than the full moon (as viewed from Earth) in a single exposure. This will give astronomers an unprecedented upperhand in spotting potentially dangerous near-Earth objects (NEOs) weeks ahead of possible impact.

“An important part of planetary defense is finding asteroids before they find us, so if necessary, we can get them before they get us,” Kelly Fast, the Near-Earth Object Observations Program Manager for NASA’s Planetary Defense Coordination Office, said in a statement. “With the addition of these two telescopes, ATLAS is now capable of searching the entire dark sky every 24 hours, making it an important asset for NASA’s continuous effort to find, track and monitor NEOs.”

NASA currently knows the location and orbit of roughly 28,000 asteroids; since it came online in 2017, ATLAS has detected more than 700 near-Earth asteroids and 66 comets. Two of the asteroids detected by ATLAS, 2019 MO and 2018 LA, actually hit Earth, the former exploding off the south coast of Puerto Rico and the latter landing near the border of Botswana and South Africa. Fortunately, the two asteroids were small and didn’t cause any damage.

While the majority of near-Earth objects aren’t as cataclysmic as the comet that featured in the 2021 satirical disaster movie “Don’t Look Up,” there are still plenty of devastating asteroid impacts in recent history to justify the expansion of monitoring. In March 2021, a bowling ball-sized meteor exploded over Vermont with the force of 440 pounds (200 kilograms) of TNT, Live Science previously reported; but those fireworks have nothing on the most explosive recent meteor event, which occurred near the central Russian city of Chelyabinsk in 2013. As the Chelyabinsk meteor struck the atmosphere, it generated a blast roughly equal to around 400-500 kilotons of TNT, or 26 to 33 times the energy released by the Hiroshima bomb. Fireballs rained down over the city and its environs, damaging buildings, smashing windows and injuring approximately 1,200 people.

NASA has been stepping up its asteroid spotting and deflection efforts in recent years. Beyond implementing in December 2021 an upgraded impact trajectory calculator called Sentry-II, the space agency also launched a one-way mission to crash a spacecraft into the distant asteroid Didymos in November 2021, Live Science previously reported. The mission — called Double Asteroid Redirection Test (DART) — will measure the effectiveness of a controlled collision at deflecting space rocks, and it could form the basis of a future planetary asteroid defense system.

For now, NASA says that it has seen no Earth-threatening asteroids, but agency scientists are keeping their eyes peeled.

“We have not yet found any significant asteroid impact threat to Earth, but we continue to search for that sizable population we know is still to be found. Our goal is to find any possible impact years to decades in advance, so it can be deflected with a capability using technology we already have, like DART,” Lindley Johnson, planetary defense officer at NASA Headquarters, said in the statement. “DART, NEO Surveyor and ATLAS are all important components of NASA’s work to prepare Earth should we ever be faced with an asteroid impact threat.”

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Possible 3rd planet spotted around Proxima Centauri, the sun’s nearest neighbor star

The candidate planet Proxima d is estimated to be just 25% as massive as Earth.

This artist’s impression shows a close-up view of Proxima d, a planet candidate recently found orbiting the red dwarf star Proxima Centauri, the closest star to our solar system. The planet is believed to be rocky and to have a mass about a quarter that of Earth. Two other planets known to orbit Proxima Centauri are visible in the image, too: Proxima b, a planet with about the same mass as Earth that orbits the star every 11 days and is within the habitable zone, and candidate Proxima c, which is on a five-year orbit around the star.

The sun’s nearest neighbor may actually host three planets, a new study reports.

Astronomers have found evidence of a third planet circling Proxima Centauri, a red dwarf star that lies a mere 4.2 light-years from our solar system. The candidate world, known as Proxima d, is estimated to be just 25% as massive as Earth, making it one of the lightest known exoplanets if it ends up being confirmed.

“The discovery shows that our closest stellar neighbor seems to be packed with interesting new worlds, within reach of further study and future exploration,” study lead author João Faria, a researcher at the Instituto de Astrofísica e Ciências do Espaço in Portugal, said in a statement.

Proxima Centauri is known to host one planet for sure — the roughly Earth-size Proxima b, which completes one orbit every 11 Earth days. That puts Proxima b in the star’s “habitable zone,” the just-right range of orbital distances where liquid water could exist on a world’s surface.

Proxima b was spotted in 2016. Three years later, researchers reported the detection of a possible second world in the system, a candidate called Proxima c that’s at least six times more massive than Earth. If Proxima c exists, it’s likely too cold to host life as we know it on its surface; the putative planet takes 5.2 years to complete one orbit around Proxima Centauri, which is much smaller and dimmer than the sun.

Now, Faria and his colleagues report the existence of another candidate in the system: Proxima d, which completes one lap around Proxima Centauri every five Earth days. That orbit suggests that Proxima d is too hot to host Earth-life surface life, if the planet does indeed exist (though the habitable zone is a squishy and tricky concept that should not be taken as gospel). (Like Proxima c, Proxima d still needs to be confirmed by follow-up observations.)

The team spotted Proxima d using ESPRESSO (“Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations”), an instrument installed on the European Southern Observatory’s (ESO) Very Large Telescope in Chile.

ESPRESSO detected the first hints of a possible third world in the Proxima Centauri system in 2020, while making observations that confirmed the existence of Proxima b. Faria and his team then conducted follow-up measurements, which suggested that the new signal is being generated by a planet rather than other factors, such as variable stellar activity.

This image of the sky around the bright star Alpha Centauri AB also shows the much fainter red dwarf star, Proxima Centauri, the closest star to our solar system. The photo was created from pictures forming part of the Digitized Sky Survey 2. The blue halo around Alpha Centauri AB is an artifact of the photographic process; the star is actually pale yellow in color like our sun.

ESPRESSO finds planets via the radial velocity technique, noticing the slight wobbles in a star’s motion induced by the gravitational tug of an orbiting world. In the case of Proxima d, these tugs were very slight indeed, corresponding to a planet with a minimum mass one-quarter that of Earth. That would make Proxima d the lightest planet ever detected using the radial velocity method, the researchers wrote in the new study, which was published online today (Feb. 10) in the journal Astronomy & Astrophysics.

“This achievement is extremely important,” study co-author Pedro Figueira, the ESPRESSO instrument scientist at ESO in Chile, said in the same statement. “It shows that the radial velocity technique has the potential to unveil a population of light planets, like our own, that are expected to be the most abundant in our galaxy and that can potentially host life as we know it.”

“This result clearly shows what ESPRESSO is capable of and makes me wonder about what it will be able to find in the future,” Faria added.

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Incredibly rare stellar merger may have created strange stars

An artist’s depiction of two white dwarf stars merging.

Two particularly strange stars may have formed in a lucky collision, according to new research.

What makes these two stars unusual is the high levels of carbon and oxygen at the surface of their atmospheres. Those elements are left behind as a star burns its helium, but that process takes place in the star’s core and wraps up long before carbon and oxygen start to dominate the star’s atmosphere. Weirdly, these stars seem to still be running through helium despite their odd surfaces.

“Normally we expect stars with these surface compositions to have already finished burning helium in their cores, and to be on their way to becoming white dwarfs,” Klaus Werner, an astronomer at the University of Tübingen in Germany and lead author of one new study of these strange stars, said in a statement from the Royal Astronomical Society (RAS), which published the new research in its journal. “These new stars are a severe challenge to our understanding of stellar evolution.”

Specifically, the scientists looked at two stars dubbed PG1654+322 and PG1528+025. Except for the high levels of carbon and oxygen in their atmospheres, these two stars look like other small, hot stars on their way to becoming white dwarfs, the dense “stellar corpses” left behind when small and medium stars run out of fuel to burn.

And yet, because of the size and temperatures of these two stars, astronomers believe these objects are still burning helium. But usually, stars sport the light elements hydrogen and helium at their surfaces, not the much heavier carbon and oxygen.

A second team of scientists has proposed a theory for how these strange stars may have come to be.

“We believe the stars discovered by our German colleagues might have formed in a very rare kind of stellar merger event between two white dwarf stars,” Marcelo Miller Bertolami, an astronomer at the Institute for Astrophysics of La Plata in Argentina and lead author of the second paper, said in the RAS statement.

“Usually, white dwarf mergers do not lead to the formation of stars enriched in carbon and oxygen,” Miller Bertolami said, “but we believe that, for binary systems formed with very specific masses, a carbon- and oxygen-rich white dwarf might be disrupted and end up on top of a helium-rich one, leading to the formation of these stars.”

Even with that explanation, however, the observations astronomers have gathered still don’t quite add up, and scientists aren’t sure how the collision would occur in the first place. That means the researchers in particular want to focus on models exploring the behavior of binary stars, pre-merger.

The results are described in two papers published Jan. 7 and Feb. 12 in the journal Monthly Notices of the Royal Astronomical Society.

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Todd

Scientists spot 10,000th medium near-Earth asteroid in planetary defense milestone

Scientists watching the skies for asteroids that may threaten Earth have hit a new milestone, spotting the 10,000th sizable space rock that circles the sun near Earth’s orbit.
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An artist’s depiction of asteroids passing near Earth.
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What’s the maximum number of planets that could orbit the sun?

The solar system contains eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune, all of which circle the sun due to its intense gravitational pull. But is this the maximum number of planets that can orbit the sun? Or is there room for more?
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An artist’s impression of the planets in the solar system, not to scale.

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What is Space?

We often refer to our expanding universe with one simple word: space. But where does space begin and, more importantly, what is it?

Space is an almost perfect vacuum, nearly void of matter and with extremely low pressure. In space, sound doesn’t carry because there aren’t molecules close enough together to transmit sound between them. Not quite empty, bits of gas, dust and other matter floats around “emptier” areas of the universe, while more crowded regions can host planets, stars and galaxies.
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What is space? In this image you can see the planetary nebula NGC 6891 glows in this Hubble Space Telescope image.
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Astronomers discover massive radio galaxy 100 times larger than the Milky Way

Astronomers have discovered the largest radio galaxy ever, stretching at least 16 million light-years through space, new research shows.

The galaxy — named Alcyoneus after the son of Ouranos, the Greek primordial god of the sky — was discovered about 3 billion light-years from Earth by a “stroke of luck,” according to a statement from Leiden University in the Netherlands.

Radio galaxies house supermassive black holes at their cores. As matter falls into the black hole, it releases energy in the form of two radio jets from opposite sides from the galaxy’s center, also known as an active galactic nucleus.
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A joint radio-infrared view of Alcyoneus, a radio galaxy with a projected proper length of 5.0 megaparsecs. Researchers superimposed images from the LOFAR Two-meter Sky Survey (LoTSS), shown in orange, with images from the Wide-field Infrared Survey Explorer (WISE), shown in blue.

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‘Tatooine-like’ planet spotted from Earth points to future discoveries

Astronomers want to spot more such worlds with double sunrises.

Kepler-16b, seen in this artist’s impression, orbits two stars and has double sunsets, just like Tatooine in Star Wars.

A ground-based telescope’s detection of a known Tatooine-like planet could herald new discoveries of similar planets, researchers say.

Observers spotted Kepler-16b — an exoplanet that orbits two stars, similar to a world portrayed in the original series of “Star Wars” — using a relatively modest 75-inch (193-centimeter) telescope. The telescope is situated at Observatoire de Haute-Provence, roughly 60 miles (100 kilometers) north of Marseilles, France. The University of Birmingham-led research team said that the detection shows the value of using a ground-based telescope “at greater efficiency and lower cost than by using spacecraft.”

The planet was originally found in space using the transit method, during which the planet passed in front of one of its stars in front of the now-retired NASA Kepler space telescope. The France-based telescope confirmed the world through the radial velocity method, which looks at the gravitational tugs a planet induces on its parent star or stars.

The team says the discovery heralds a new series of work they plan to perform concerning so-called “circumbinary planets,” meaning planets that orbit two stars.

The scientists hope their telescope will next find previously unknown planets of this type, helping astronomers learn how planetary formation occurs in a solar system with two stars. Traditionally, planets are believed to form in a protoplanetary disk of gas and dust surrounding a young star, but it’s not clear if circumbinary systems could support this environment.

“Using this standard explanation, it is difficult to understand how circumbinary planets can exist,” lead author Amaury Triaud, a Birmingham exoplanet researcher, said in the statement. “That’s because the presence of two stars interferes with the protoplanetary disk, and this prevents dust from agglomerating into planets, a process called accretion.”

Artist’s conception of a protoplanetary disc around a newborn star.

Triaud suggested the planet might have instead formed far away from the two stars and then migrated inward. But more study could reveal alternate scenarios forming double-starred planets, which in turn may shape scientists’ theories about how planets form more generally.

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Strangely tilted black hole challenges formation theories

Artist impression of the X-ray binary system containing a black hole (small black dot at the center of the accretion disk) and a companion star. The jet that is directed along the black hole spin axis is strongly misaligned from the rotation axis of the orbit.

A tilted black hole spinning around a misaligned axis has been discovered in our galaxy, challenging theories of black hole formation.

The black hole and its companion star form a system called MAXI J1820+070, which lies some 10,000 light-years away from Earth. The system was first spotted by NASA’s Chandra X-ray Observatory in 2018. But recent optical observations by the Nordic Optical Telescope in the Canary Islands revealed that the black hole behaves in ways that defy astronomers’ expectations.

By studying the orientation of the jets of ionized matter emitted from the black hole’s poles, Juri Poutanen, an astronomer at the University of Turku in Finland, discovered that the black hole spins around an axis that is tilted by at least 40 degrees toward the plane in which the block hole orbits its companion star. That’s the largest misalignment ever reported, Poutanen and his colleagues said in a statement.

“We observed black hole X-ray binary MAXI J1820+070 with a high-precision optical polarimeter,” Poutanen told Space.com in an email. “Using these data, we determined the position angle of the binary orbit on the sky. The black hole spin orientation can be obtained from the radio and X-ray observations of the relativistic jets observed previously from the system.”

By combining all of this information, the scientists were able to determine the angle between the axis of the binary orbit and the black hole spin, he added.

Theoretical models expect binary systems, such as black holes orbited by stars from which they suck material, to rotate around aligned axes that are perpendicular to their shared orbital plane.

Previously, astrophysicists expected that these axes could be only “marginally” misaligned, the scientists said in the statement.

The question remains what caused the misalignment in MAXI J1820+070. The scientists believe that, contrary to current models of black hole formation following supernova explosions, the black hole in MAXI J1820+070 must have received a “kick” during the explosion that gave rise to it.

The authors found it improbable for this misalignment to arise at a later stage, as accretion of material between two bodies of a binary system and the gravitational forces between them “always bring axes closer into alignment,” the authors said.

The finding could have wider consequences for black hole science, the scientists said, as such misalignments could bias measurements of black hole masses and spins.

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Todd

Sean Robinson wrote:

Astronomers want to spot more such worlds with double sunrises.

too bad it does not have a Earthlike atmosphere then we can get this

Double Double Rainbows

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Todd, Sean Robinson

5,000 exoplanets! NASA confirms big milestone for planetary science

The exoplanet revolution is well underway

Our tally of strange, new worlds just reached 5,000.

Astronomers have added the 5,000th alien world to the NASA Exoplanet Archive, officials with the agency’s Jet Propulsion Laboratory (JPL) in Southern California announced on Monday (March 21).

The milestone comes amid a surge of recent discoveries and the promise of more insights to come, as NASA’s $10 billion James Webb Space Telescope readies for planet-gazing operations in deep space.

“The 5,000-plus planets found so far include small, rocky worlds like Earth, gas giants many times larger than Jupiter, and ‘hot Jupiters’ in scorchingly close orbits around their stars,” JPL officials said in Monday’s statement.

“There are ‘super-Earths,’ which are possible rocky worlds bigger than our own, and ‘mini-Neptunes,’ smaller versions of our system’s Neptune,” JPL officials added. “Add to the mix planets orbiting two stars at once and planets stubbornly orbiting the collapsed remnants of dead stars.”

The NASA Exoplanet Archive is housed at the California Institute for Technology (Caltech). To be added to the catalog, planets must be independently confirmed by two different methods, and the work must be published in a peer-reviewed journal.

The first exoplanets were found in the early 1990s. While telescopes on the ground and in space have done well to get the count to 5,000 since then, Jessie Christiansen, science lead of the NASA Exoplanet Archive, stated on Caltech’s website that the worlds found to date are “mostly in this little bubble around our solar system, where they are easier to find.”

“Of the 5,000 exoplanets known, 4,900 are located within a few thousand light-years of us,” Christiansen added. “And think about the fact that we’re 30,000 light-years from the center of the galaxy; if you extrapolate from the little bubble around us, that means there are many more planets in our galaxy we haven’t found yet, as many as 100 to 200 billion. It’s mind-blowing.”

The first confirmed planetary discovery came in 1992, when astronomers Alex Wolszczan and Dale Frail published a paper in the journal Nature. They spotted two worlds orbiting a pulsar (a rapidly rotating, dense star corpse) by measuring subtle changes in the timing of the pulses as the light reached Earth.

Ground-based telescopes did the heavy lifting in those early years, and it took several more searches to finally uncover the first planet around a sun-like star in 1995. That world was not hospitable to life as we know it; it was a scorching-hot gas giant that whipped around its parent star in only four Earth days.

Astronomers found these worlds by spotting wobbles (back and forth gravitationally induced motions) of stars as planets tugged upon them. Larger worlds were easier to spot, as they induced bigger wobbles. To find more Earth-sized planets, astronomers said at the time, they would need to try something called the “transit” method. That would assess the light of a star and look for tiny fluctuations as a planet passed across the face.

Astronomer William Borucki helped realize that vision as the principal investigator of NASA’s Kepler space telescope, which launched in 2009 and exceeded its main mission by several years until it finally ran out of fuel in 2018. Kepler has racked up more than 2,700 planet discoveries to date, many of them Earth-sized or smaller worlds, and still has a database generating fresh finds to this day.

Many other instruments have joined the planet hunt since Kepler launched. On the ground, the HARPS spectrograph, which is part of the 11.8-foot (3.6-meter) telescope at the European Southern Observatory’s La Silla Observatory in Chile, is an adept planet-hunter of its own.

By 2011 (eight years after first light), HARPS had discovered more than 150 exoplanets. While access has been restricted periodically in latter years due to the coronavirus pandemic, HARPS remains operational and continues to seek new worlds with high precision.

In space, numerous observatories also assist with the planet search, among them NASA’s Transiting Exoplanet Survey Satellite (TESS), the NASA-European Space Agency (ESA) Hubble Space Telescope, and ESA’s Characterizing Exoplanet Satellite (CHEOPS). Several other huge telescopes under construction on the ground, including the Giant Magellan Telescope and the Extremely Large Telescope in Chile, are scheduled to come online later this decade, adding other powerful eyes to the ongoing search.

Webb will help enhance the tally of exoplanets by studying the atmospheres of several relatively nearby worlds in detail. While such work may focus largely on gas giants, scientists say Webb’s observations will be useful for a future generation of observatories with even more high-powered optics ready to see planets closer in size to Earth.

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Another search for Planet 9 comes up empty

‘Results … are generally consistent with other null searches for Planet 9.’

Artist’s illustration of Planet Nine, a world about 10 times more massive than Earth that may lie undiscovered in the far outer solar system.

A theorized huge, ninth planet beyond the orbit of Neptune once again wasn’t found in a new survey of the solar system’s outer reaches.

Astronomers scanned a large portion of the sky using the 6-meter Atacama Cosmology Telescope (ACT) in Chile to search for Planet 9. The quest came up empty, according to the scientists behind the research, although they acknowledged that more sensitive searches would make the result more definitive.

“Their search found many tentative candidate sources — about 3,500 of them — but none could be confirmed, and there were no statistically significant detections,” the Harvard-Smithsonian Center for Astrophysics, a participating institution in the research, said in a release March 11.

That said, in the scanned area of the sky, scientists were “able to exclude with 95% confidence” a world with the supposed properties of Planet 9, the release added, “results that are generally consistent with other null searches for Planet 9.”

It’s the latest in a string of fruitless searches in the past decade, after a team of astronomers Chadwick A. Trujillo (then of Gemini Observatory) and Scott S. Sheppard (of the Carnegie Institution for Science) argued in Nature in 2014 that such a large world might explain a strange large gravity source in deep solar space.

The team behind the new research acknowledged how tough the search would be to find such a planet. In theory, Planet 9 appears to be five to 10 times the size of Earth and roughly 400 to 800 Earth-sun distances away from the sun. (The Earth and sun are on average, 93 million miles or 150 million kilometers apart.)

The existence of a roughly Neptune-mass Planet Nine could explain why the few known extreme trans-Neptunian objects seem to be clustered together in space. The diagram was created using WorldWide Telescope.

A small planet so far away would be tough to spot in optical searches because the world would see very little sunlight at such great orbital distances. Even searching for infrared or heat signatures is tough, as infrared surveys such as the Wide-field Infrared Explorer (WISE) were unable to find Planet 9 in past attempts, the team noted.

The newly used Atacama Cosmology Telescope usually looks for the signature of the Big Bang, also known as cosmic microwave background radiation. But repurposing the telescope for Planet 9 had value as “its relatively high angular resolution and sensitivity makes it suitable for this type of search,” the team stated.

The astronomers looked at 87% of the sky accessible from the southern hemisphere over six years, and then processed the images to search for faint sources. Although the results so far have come up empty, the team acknowledged in the statement that more advanced surveys may yield more information.

The researchers are particularly excited to see the results of a project based in Chile called the Simons Observatory that will also spend most of its time spending the cosmic microwave background.

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Our universe may have a twin that runs backward in time

An anti-universe running backwards in time could explain dark matter and cosmic inflation.

If the universe has a twin and on that twin time runs backward, then scientists could explain dark matter.

A wild new theory suggests there may be another “anti-universe,” running backward in time prior to the Big Bang.

The idea assumes that the early universe was small, hot and dense — and so uniform that time looks symmetric going backward and forward.

If true, the new theory means that dark matter isn’t so mysterious; it’s just a new flavor of a ghostly particle called a neutrino that can only exist in this kind of universe. And the theory implies there would be no need for a period of “inflation” that rapidly expanded the size of the young cosmos soon after the Big Bang.

If true, then future experiments to hunt for gravitational waves, or to pin down the mass of neutrinos, could answer once and for all whether this mirror anti-universe exists.

Preserving symmetry

Physicists have identified a set of fundamental symmetries in nature. The three most important symmetries are: charge (if you flip the charges of all the particles involved in an interaction to their opposite charge, you’ll get the same interaction); parity (if you look at the mirror image of an interaction, you get the same result); and time (if you run an interaction backward in time, it looks the same).

Physical interactions obey most of these symmetries most of the time, which means that there are sometimes violations. But physicists have never observed a violation of a combination of all three symmetries at the same time. If you take every single interaction observed in nature and flip the charges, take the mirror image, and run it backward in time, those interactions behave exactly the same.

This fundamental symmetry is given a name: CPT symmetry, for charge (C), parity (P) and time (T).

In a new paper recently accepted for publication in the journal Annals of Physics, scientists propose extending this combined symmetry. Usually this symmetry only applies to interactions — the forces and fields that make up the physics of the cosmos. But perhaps, if this is such an incredibly important symmetry, it applies to the whole entire universe itself. In other words, this idea extends this symmetry from applying to just the “actors” of the universe (forces and fields) to the “stage” itself, the entire physical object of the universe.

Creating dark matter

We live in an expanding universe. This universe is filled with lots of particles doing lots of interesting things, and the evolution of the universe moves forward in time. If we extend the concept of CPT symmetry to our entire cosmos, then our view of the universe can’t be the entire picture.

Instead, there must be more. To preserve the CPT symmetry throughout the cosmos, there must be a mirror-image cosmos that balances out our own. This cosmos would have all opposite charges than we have, be flipped in the mirror, and run backward in time. Our universe is just one of a twin. Taken together, the two universes obey CPT symmetry.

The study researchers next asked what the consequences of such a universe would be.

They found many wonderful things.

For one, a CPT-respecting universe naturally expands and fills itself with particles, without the need for a long-theorized period of rapid expansion known as inflation. While there’s a lot of evidence that an event like inflation occurred, the theoretical picture of that event is incredibly fuzzy. It’s so fuzzy that there is plenty of room for proposals of viable alternatives.

Second, a CPT-respecting universe would add some additional neutrinos to the mix. There are three known neutrino flavors: the electron-neutrino, muon-neutrino and tau-neutrino. Strangely, all three of these neutrino flavors are left-handed (referring to the direction of its spin relative to its motion). All other particles known to physics have both left- and right-handed varieties, so physicists have long wondered if there are additional right-handed neutrinos.

A CPT-respecting universe would demand the existence of at least one right-handed neutrino species. This species would be largely invisible to physics experiments, only ever influencing the rest of the universe through gravity.

But an invisible particle that floods the universe and only interacts via gravity sounds a lot like dark matter.

The researchers found that the conditions imposed by obeying CPT symmetry would fill our universe with right-handed neutrinos, enough to account for the dark matter.

Predictions in the mirror

We would never have access to our twin, the CPT-mirror universe, because it exists “behind” our Big Bang, before the beginning of our cosmos. But that doesn’t mean we can’t test this idea.

The researchers found a few observational consequences of this idea. For one, they predict that the three known left-handed neutrino species should all be Majorana particles, which means that they are their own antiparticles (in contrast to normal particles like the electron, which have antimatter counterparts called the positrons). As of now, physicists aren’t sure if neutrinos have this property or not.

Additionally, they predict that one of the neutrino species should be massless. Currently, physicists can only place upper limits on the neutrino masses. If physicists can ever conclusively measure the neutrino masses, and one of them is indeed massless, that would greatly bolster the idea of a CPT-symmetric universe.

Lastly, in this model the event of inflation never occurred. Instead, the universe filled with particles naturally on its own. Physicists believe that inflation shook space-time to such a tremendous degree that it flooded the cosmos with gravitational waves. Many experiments are on the hunt for these primordial gravitational waves. But in a CPT-symmetric universe, no such waves should exist. So if those searches for primordial gravitational waves turn up empty, that might be a clue that this CPT-mirror universe model is correct.

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Sean Robinson wrote:

Our universe may have a twin that runs backward in time

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Sun erupts with 17 flares from single sunspot, sending solar storms toward Earth

We might see some auroras in the coming days.

At least 17 solar eruptions from a single sunspot on the sun have blasted into space in recent days, including some charged particles that may create a colorful sky show on Earth.

The sun eruptions originated from an overactive sunspot, called AR2975, which has been firing off flares since Monday (March 28). We may soon see some moderate sky storms on Earth due to the stellar event.

Sunspots are eruptions on the sun that occur when magnetic lines twist and suddenly realign near the visible surface. At times, these explosions are associated with coronal mass ejections (CMEs), or streams of charged particles that shoot into space. NASA’s powerful Solar Dynamics Observatory captured stunning views of the solar eruptions, as did the the Solar and Heliospheric Observatory.

“The eruptions have hurled at least two, possibly three, CMEs toward Earth,” wrote SpaceWeather.com of the event. NASA and the National Oceanic and Atmospheric Administration, the website added, suggest the first CME will arrive on Thursday (March 31), with at least one other expected on Friday (April 1.)

One of 17 different flares from an active sunspot AR 2975 shines bright in this image from NASA’s Solar Dynamics Observatory taken on March 28-29, 2022.

Modeling suggests that the particles may generate G2 or G3 (moderate) geomagnetic storms, although auroras (northern lights and southern lights) are notoriously hard to predict.

The year 2022 is expected to be relatively quiet for the sun overall, as we are still towards the beginning of the 11-year solar cycle of activity that began in December 2019. Cycle beginnings usually have fewer sunspots and fewer eruptions. Activity should increase as we approach the peak, forecasted to be in mid-2025.

Several coronal mass ejections in March 2022 were captured by the Solar and Heliospheric Observatory (SOHO).

Scientists are debating how strong this current solar cycle will be, although forecasts so far indicate that the average number of sunspots may be lower than usual.

While this possible storm is only moderate, NASA and other space agencies keep an eye on solar activity to improve solar weather predictions. A strong flare aimed towards Earth, along with a large CME, may induce problems such as damaging power lines or disabling satellites.

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Sean Robinson wrote:

A wild new theory suggests there may be another “anti-universe,” running backward in time prior to the Big Bang.

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Space Calendar

April 1: The new moon arrives at 2:24 a.m. EDT (0546 GMT)

April 4: Saturn and Mars will make a close approach in the dawn sky, coming within less than one-third of a degree of one another. Look for the pair in the constellation Capricornus before sunrise.

April 16: The full moon of April, known as the Pink Moon, arrives at 2:55 p.m. EDT (1855 GMT).

April 21-22: The Lyrid meteor shower peaks.

April 30: A partial solar eclipse will be visible from southern South America, parts of Antarctica, and over the Pacific and Atlantic Oceans. This eclipse coincides with the second new moon of April, also known as a Black Moon.

May 4-5: The Eta Aquarid meteor shower peaks.

May 16: The full moon of May, known as the Flower Moon, arrives at 12:14 a.m. EDT (0414 GMT).

May 16-17: A total lunar eclipse, also known as a Blood Moon, will be visible from North and South America, Europe, Africa and parts of Asia.

May 29: Jupiter and Mars will make a close approach in the dawn sky and will be just over one-half degree apart. While they won’t be close enough to glimpse together by telescope, the planets will be visible together with the naked eye or in a pair of binoculars.

May 30: The new moon arrives at 7:30 a.m. EDT (1230 GMT).

June 14: The full moon of June, known as the Strawberry Moon, arrives at 7:52 a.m. EDT (1152 GMT). It will also be the first “supermoon” of the year.

June 21: Solstice. Today marks the first day of summer in the Northern Hemisphere and the first day of winter in the Southern Hemisphere.

June 28: The new moon arrives at 10:52 p.m. EDT (0252 June 29 GMT).

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A hyperactive sunspot just hurled a huge X-class solar flare into space

The flare even caused a shortwave radio blackout.

The sun produced an X-class flare on March 30, 2022; this data from NASA’s Solar Dynamics Observatory shows the extreme ultraviolet light of the flare in yellow.

A fast-erupting sunspot just hurled out a huge flare.

The hotbed of sun activity, known officially as AR2975, sent out a powerful X-class flare that has already created a temporary blackout in shortwave radio signals in the Americas, according to SpaceWeather.com. (AR2975 has already burped more than 17 moderate-sized flares in recent days, but this outburst is a bit more powerful.)

“Aviators, mariners, and ham radio operators may have noticed unusual propagation effects at frequencies below 30 MHz [megahertz],” the website reported Wednesday (March 30) in the hours after the flash.

Solar flares are ranked first by category — A-class are weakest, then B-, C-, and M-class, with X-class the strongest — and then by size, with smaller numbers representing smaller flares within the class. Wednesday’s flare was an X1.3-class flare, according to SpaceWeather.

Flares are outbursts of light, but are sometimes related to coronal mass ejections (CMEs), which shoot blobs of charged particles out into space. If a coronal mass ejection emerges from the flare and is pointed toward Earth, that could cause auroras, the stunning light shows caused by charged particles hitting Earth’s atmosphere. SpaceWeather added that there is circumstantial evidence suggesting a CME is emerging from the sun, but more observations will be required to confirm that.

“A CME is almost certainly emerging from the blast site,” SpaceWeather continued, noting that the U.S. Air Force has detected a Type II solar radio burst that can be associated with the shock waves of a CME.

“Also, NASA’s Solar Dynamics Observatory has imaged a solar tsunami apparently generated by a CME leaving the sun’s atmosphere,” SpaceWeather added.

SDO officially caught imagery of the event at 1:35 p.m. EST (1835 GMT), but NASA did not provide a detailed forecast beyond pointing to generic risks that may happen with solar flares.

“Flares and solar eruptions can impact radio communications, electric power grids, navigation signals, and pose risks to spacecraft and astronauts,” NASA officials wrote in a statement.

The sun began its current cycle of solar activity in 2019, and is expected to reach the peak around 2025. Scientists aren’t yet sure how active this solar cycle will be, although the forecast is for fewer sunspots than usual.

NASA and other space agencies constantly keep watch on solar activity to improve solar weather predictions. In most cases, CMEs simply cause auroras as charged particles hit the magnetic lines of Earth. More powerful storms, however, may cause issues with satellites or power lines.

______________________________________

Earth braces for solar storm, potential aurora displays

Auroras can be visible as far south as Pennsylvania.

A powerful solar storm is set to hit Earth on Thursday (March 31) with spectacular aurora displays accompanying it after the sun fired nearly 20 flares from a single sunspot in just two days.

The U.S. National Oceanic and Atmospheric Administration (NOAA) warned that two coronal mass ejections (CMEs), spat out from the overactive sunspot AR2975, on Monday (March 28), are heading toward our planet and might trigger a geomagnetic storm rated as G3 on NOAA’s five-point scale.

CMEs are huge expulsions of magnetized particles released from the sun’s upper atmosphere, the corona. If those charged clouds hit Earth, they can wreak havoc with the planet’s magnetic field, causing disruptions to satellites, electric grids and telecommunication networks.

A G3-level solar storm, NOAA said in a statement, is unlikely to have serious impacts on infrastructure. However, it might trigger stunning aurora displays that could be visible from locations more distant from the poles than regions where auroras are usually seen.

“Auroras for this storm may be visible, if the weather conditions are favorable, as far south as Pennsylvania to Iowa to Oregon and points north,” NOAA said in the statement.

Since Earth’s magnetic field is the weakest above the poles, solar particles penetrate much deeper into the planet’s atmosphere in those regions. The interaction between the charged solar particles and particles in Earth’s atmosphere then triggers the spectacular polar light displays. During powerful solar storms, these areas where auroras occur, also known as auroral ovals, expand farther away from the poles.

The U.K.’s national weather forecaster Met Office said in a statement that auroras could be visible from Scotland and Northern Ireland on Thursday (March 31). In the Southern Hemisphere, the aurora oval could expand up to 55 degrees latitude, just south of New Zealand and the southern tip of South America.

NOAA has issued a Geomagnetic Storm Watch through Friday (April 1). A minor (G1) alert is in place for Wednesday (March 30), which will increase to moderate (G2) as the storm arrives.

The Met Office expects additional moderate-class solar flares could occur in the upcoming days.

The solar storm and associated phenomena are tied to the sun’s currently increasing activity as part of what scientists call solar cycle 25. The sun’s activity fluctuates on an 11-year cycle, which had been at its minimum level of activity in the past years. Scientists predict that the solar cycle will hit its maximum in 2025; sunspots, CMEs and solar storms are likely to continue increasing in frequency throughout the coming years.

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[Sean Robinson]

Hubble Space Telescope spots most distant single star ever seen

Meet Earendel, a star 12.9 billion light-years from Earth.

The most distant star yet seen, called Earendel, is indicated by an arrow in the inset of this image from the Hubble Space Telescope that captured the star from 12.9 billion light-years away using a gravitational lens.

The most distant single star seen yet dates back to less than 1 billion years after the universe’s birth in the Big Bang, and may shed light on the earliest stars in the cosmos, a new study finds.

The scientists nicknamed the star “Earendel,” from an Old English word meaning “morning star” or “rising light.” Earendel, whose technical designation is WHL0137-LS, is at least 50 times the mass of the sun and millions of times as bright.

This newfound star, detected by NASA’s Hubble Space Telescope, is so far away that its light has taken 12.9 billion years to reach Earth, appearing to us as it was when the universe was about 900 million years old, just 7% of its current age. Until now, the most distant single star detected, discovered by Hubble in 2018, existed when the universe was about 4 billion years old, or 30% of its current age.

“This finding gives us an opportunity to study a star in detail in the early universe,” study lead author Brian Welch, an astrophysicist at Johns Hopkins University in Baltimore, told Space.com.

Normally, even a star as brilliant as Earendel would be impossible to see from Earth given the vast divide between the two. Previously, the smallest objects seen at such a great distance were clusters of stars embedded inside early galaxies.

Scientists detected Earendel with the help of a huge galaxy cluster, WHL0137-08, sitting between Earth and the newfound star. The gravitational pull of this enormous galaxy cluster warped the fabric of space and time, resulting in a powerful natural magnifying glass that greatly amplified the light from distant objects behind the galaxy, such as Earendel. This gravitational lensing has distorted the light from the galaxy hosting Earendel into a long crescent the researchers named the Sunrise Arc.

The rare way in which Earendel aligned with WHL0137-08 meant that the star appeared directly on, or extremely close to, a curve in spacetime that provided maximum brightening, causing Earendel to stand out from the general glow of its home galaxy. This effect is analogous to the rippled surface of a swimming pool creating patterns of bright light on the bottom of the pool on a sunny day — the ripples on the surface act as lenses and focus sunlight to maximum brightness on the pool floor.

Welch emphasized this is not the most distant object scientists have ever discovered. “Hubble has observed galaxies at greater distances,” he explained. “However, we see the light from their millions of stars all blended together. This is the most distant object where we can identify light from an individual star.”

This zoomed-in detail view shows the location of the distant star Earendel along a ripple in space-time (dotted line) that magnified it so that the Hubble Space Telescope could spot it from 12.9 billion light-years away.

He also noted this star was distant, but not old. “We see the star as it was 12.8 billion years ago, but that does not mean the star is 12.8 billion years old,” Welch said. Instead, it’s probably just a few million years old and never reached old age.

“Given its mass, it almost certainly has not survived to today, as more massive stars tend to burn through their fuel faster and thus explode, or collapse into black holes, sooner,” he added of Earendel. “The oldest stars known would have formed at a similar time, but they are much less massive, so they have continued to shine until today.”

Many details about Earendel remain uncertain, such as its mass, brightness, temperature and type. Scientists are not even sure yet if Earendel is one star or two — most stars of Earendel’s mass usually do have a smaller, dimmer companion, and it’s possible that Earendel is outshining its partner.

Scientists intend to conduct followup observations with NASA’s recently launched James Webb Space Telescope to analyze Earendel’s infrared light and pin down many of its features. Such information in turn could help shed light on the first stars in the universe, which formed before the universe was filled with the heavy elements produced by successive generations of massive stars.

“I think one of the most exciting things about this result is that it opens a new window into the early universe,” Welch said. “Typically at these distances, we see full galaxies as small, fuzzy objects, and we then infer details about the stars within from their aggregate light.”

Not so for Earendel. “With this lensed star, we can study its light independently,” he said. “This lets us compare directly to stars in the Milky Way and look for differences which will improve our understanding of stars in the early universe.”

• This reply was modified 2 years, 9 months ago by Sean Robinson.

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‘Dead’ telescope discovers Jupiter’s twin from beyond the grave

This is the most distant exoplanet Kepler ever found.

The exoplanet, discovered by NASA’s Kepler space telescope, officially designated K2-2016-BLG-0005Lb.

NASA’s Kepler space telescope has spotted a Jupiter look-alike in a new discovery, even though the instrument stopped operations four years ago.

An international team of astrophysicists using NASA’s Kepler space telescope, which ceased operations in 2018, have discovered an exoplanet similar to Jupiter located 17,000 light-years from Earth, making it the farthest exoplanet ever found by Kepler. The exoplanet, officially designated K2-2016-BLG-0005Lb, was spotted in data captured by Kepler in 2016. Throughout its lifetime, Kepler observed over 2,700 now-confirmed planets.

“Kepler was also able to observe uninterrupted by weather or daylight, allowing us to determine precisely the mass of the exoplanet and its orbital distance from its host star,” Eamonn Kerins, an astronomer at the University of Manchester in the U.K., said in a statement. “It is basically Jupiter’s identical twin in terms of its mass and its position from its sun, which is about 60% of the mass of our own sun,”

The team, led by David Specht, a Ph.D. student at the University of Manchester, took advantage of a phenomenon known as gravitational microlensing to spot the exoplanet. With this phenomenon, which was predicted by Einstein’s theory of relativity, objects in space can be seen and studied closer when the light from a background star is warped and thus magnified by the gravity of a closer massive object.

In hopes of using the warped light from a far-off star to detect an exoplanet, the team used three months of observations that Kepler made of the stretch of sky where this planet lies.

“To see the effect at all requires almost perfect alignment between the foreground planetary system and a background star,” Kerins added in the same statement. “The chance that a background star is affected this way by a planet is tens to hundreds of millions to one against. But there are hundreds of millions of stars towards the center of our galaxy. So Kepler just sat and watched them for three months.”

The team then worked with Iain McDonald, another astronomer at the University of Manchester who developed a new search algorithm. Together, they were able to reveal five candidates in the data, with one most clearly showing signs of an exoplanet. Other ground-based observations of the same stretch of sky corroborated the same signals that Kepler saw of the possible exoplanet.

“The difference in vantage point between Kepler and observers here on Earth allowed us to triangulate where along our sight line the planetary system is located,” Kerins said.

Aside from the excitement of discovering an exoplanet with an instrument no longer even in service, the team’s work is notable because Kepler was not designed to discover exoplanets using this phenomenon. It is important to note, however, that, in 2016, Kepler’s mission was extended. In 2013, after two reaction wheel failures, it was proposed that Kepler be used for a K2 “second light” mission that would see the scope detecting potentially habitable exoplanets. This extension was approved in 2014 and the mission was extended way past the scope’s expected end date until it eventually ran out of fuel on Oct. 30, 2018.

“Kepler was never designed to find planets using microlensing so, in many ways, it’s amazing that it has done so,” Kerins said, adding that upcoming instruments like NASA’s Nancy Grace Roman Space Telescope and the European Space Agency’s Euclid mission, could be capable of using microlensing to study exoplanets and will be able to further such research.

“Roman and Euclid, on the other hand, will be optimized for this kind of work. They will be able to complete the planet census started by Kepler,” Kerins said. “We’ll learn how typical the architecture of our own solar system is. The data will also allow us to test our ideas of how planets form. This is the start of a new exciting chapter in our search for other worlds.”

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Hubble spots young gas giant forming in an ‘intense and violent’ way

An artist’s depiction of exoplanet AB Aurigae b.

The Hubble Space Telescope has spotted a young Jupiter-like protoplanet that’s supporting an unusual planetary formation theory, according to a new study.

The subject of the image is the planet AB Aurigae b, a young gas giant located some 531 light-years away from our sun that’s estimated to be about 2 million years old. Scientists know that gaseous and rocky planets form from material gathered around a star in what’s called a circumstellar disk.

But AB Aurigae b seems to be bucking long-held theories about the mechanics of planetary formation due to its size and location. In fact, according to the researchers who found this exoplanet, it seems to support an unusual planetary formation theory known as “disk instability” — one that’s been described as “intense and violent.”

For jovian planets, the most widely accepted planetary formation theory is core accretion which is “a bottom-up approach where planets embedded in the disk grow from small objects — with sizes ranging from dust grains to boulders — colliding and sticking together as they orbit a star. This core then slowly accumulates gas from the disk,”according to a statement describing this new study.

AB Aurigae b, however, orbits its star at a distance of 8.6 billion miles, which is more than twice as far as Pluto is from our sun. Given that distance, scientists would expect a planet like AB Aurigae b to take an extremely long time to form. But the protoplanet is already nine times more massive than Jupiter is, and at a very young age. Scientists believe that this is only possible through a different method called the “disk instability” approach.

This approach is”a top-down model where as a massive disk around a star cools, gravity causes the disk to rapidly break up into one or more planet-mass fragments,” according to the same statement.

To come to the conclusion that this exoplanet formed from this alternative method, researchers compared the data from Hubble’s image of AB Aurigae b with data from the ground-based planet imaging instrument SCExAO on Japan’s Subaru Telescope in Hawaii.

“The wealth of data from space and ground-based telescopes proved critical, because distinguishing between infant planets and complex disk features unrelated to planets is very difficult,” according to the statement.

In fact, it’s not just Hubble’s newest images that were used in the study — lead researcher Thayne Currie of the Subaru Telescope and Eureka Scientific noted that Hubble archival data was crucial to the findings. “We could not detect this motion on the order of a year or two years,” he said. “Hubble provided a time baseline, combined with Subaru data, of 13 years, which was sufficient to be able to detect orbital motion.”

With so much data from the two instruments, scientists were able to confirm their core accretion theory, though further observations will likely be made using the James Webb Space Telescope after it comes online later this year.

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Strange ‘reverse shock wave’ supernova is exploding in the wrong direction

Part of the shock wave is shrinking rather than expanding.

A colorized image of Cassiopeia A based on data from the Hubble, Spitzer and Chandra space telescopes.

A powerful shock wave traveling through a cloud of gas left behind by the explosive death of a star has a bizarre quirk: Part of it is traveling in the wrong direction, a new study reveals.

In the study, researchers found that the shock wave is accelerating at different rates, with one section collapsing back toward the origin of the stellar explosion, or supernova, in what the study authors call a “reverse shock.”

Cassiopeia A is a nebula, or gas cloud, left behind by a supernova in the constellation Cassiopeia, around 11,000 light-years from Earth, making it one of the closest supernova remnants. The nebula, which is around 16 light-years wide, is made of gas (mainly hydrogen) that was expelled both before and during the explosion that ripped apart the original star. A shock wave from that explosion is still rippling through the gas, and theoretical models show that this shock wave should be expanding evenly, like a perfectly rounded balloon that’s constantly being inflated.

But the researchers found that this wasn’t the case.

“For a long time, we suspected something weird was going on inside Cassiopeia A,” lead author Jacco Vink, an astronomer at the University of Amsterdam in the Netherlands, told Live Science. Previous studies had shown that the internal motions within the nebula were “rather chaotic” and highlighted that the western region of the shock wave moving through the gas cloud might even be going in the wrong direction, he added.

In the new study, the researchers analyzed the movement of the shock wave, using X-ray images collected by NASA’s Chandra X-ray Observatory, a telescope that orbits Earth. The data, collected over 19 years, confirmed that part of the western region of the shock wave was, in fact, retreating in the opposite direction in a reverse shock.

But they also discovered something even more surprising: Parts of the same region were still accelerating away from the supernova’s epicenter, like the rest of the shock wave.

Uneven expansion

The current average speed of the expanding gas in Cassiopeia A is around 13.4 million mph (21.6 million kph), which makes it one of the fastest shock waves ever seen in a supernova remnant, Vink said. This is mainly because the remnant is so young; light from Cassiopeia A reached Earth in 1970. But over time, shock waves lose their momentum to their surroundings and slow down.

Cassiopeia A consists of two main expanding bands of gas: an inner shell and an outer shell. These two shells are two halves of the same shock wave, and across most of the nebula, the inner and outer shells are traveling at the same speed and in the same direction. But in the western region, the two shells are going in opposite directions: The outer shell is still expanding outward, but the inner shell is moving back toward where the exploding star would have been.

An image of Cassiopeia A showing the shock wave move through the inner and outer shells of gas. The blue arrows show the western section of the inner shell moving back towards the center of the nebula.

The reverse shock is retreating at around 4.3 million mph (6.9 million kph), which is about a third of the average expansion speed of the rest of the nebula. However, what really puzzled the researchers was how fast the outer shell was expanding compared with the retreating inner shell in this region. The researchers had expected the outer shell to be expanding at a decreased rate compared with the rest of the shock wave, but they found that it was actually accelerating faster than some other regions of the shock wave. “That was a total surprise,” Vink said.

Cosmic collision

The unusual expansion within Cassiopeia A’s western region does not match up with theoretical supernova models and suggests that something happened to the shock wave in the aftermath of the stellar explosion, Vink said.

The researchers said the most likely explanation is that the shock wave collided with another shell of gas that was likely ejected by the star before it exploded. As the shock wave hit this gas, it may have slowed down and created a pressure buildup that pushed the inner shell back toward the center. However, the outer shell still may have been forced through this blockage and begun to accelerate again on the other side, Vink said. “This explains both the inward movement of the inner shell but also predicts that the outer shell should be accelerating, as indeed we measured,” he added.

The researchers also think the unique way the original star died could explain the uneven shock wave. Cassiopeia A is the result of a Type IIb supernova, in which a massive star exploded after it had almost completely shed its outer layers, Vink said.

An image of Cassiopeia A combining X-ray data collected by NASA’s Imaging X-ray Polarimetry Explorer, shown in magenta, and NASA’s Chandra X-Ray Observatory, in blue.

“X-ray estimates suggest that the star was around four to six times the mass of the sun during the explosion,” Vink said, but the star most likely had a mass of around 18 times the sun when it was born. This means the star lost around two-thirds of its mass, most of which would have been hydrogen, before it exploded; The shock wave may have later collided with this gas, Vink said.

There are several theories as to why Cassiopeia A lost so much of its mass before it exploded. In September 2020, another team of researchers proposed that the original star was part of a binary star system, where two stars orbit each other. That research team said this companion star also could have gone supernova before Cassiopeia A and blasted off the star’s hydrogen “skin” in the process, Live Science previously reported(opens in new tab).

However, the authors of the new study are unconvinced by this theory. “The only problem is that we have not yet found the remains of the other star,” Vink said. “So, at this stage, it remains speculative.”

So for now, no one knows exactly what is fueling Cassiopeia A’s uneven shock wave.

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Todd

Rare ‘black widow’ star system could help unlock the secrets of space-time

This cannibal star system could be a gravitational wave detecting machine.

An artist’s rendering of a pulsar surrounded by a glowing disk of matter. In ‘black widow’ pulsars, that matter comes from a smaller companion star that’s slowly being irradiated out of existence.

Every 4 milliseconds, a dead star blasts a powerful beam of radiation toward our planet. Don’t worry — Earth will be fine. It’s the dead star’s tiny companion that’s in trouble.

In a new study published March 11 on the pre-print database arXiv(opens in new tab), researchers describe this ill-fated binary star system — a rare class of celestial object known as a black widow pulsar(opens in new tab). Just like the cannibal spider from which this type of system takes its name, the larger member of the pair seems intent on devouring and destroying its smaller companion. (In spiders, females are often larger than males.)

However, there will be no quick decapitation for this black widow; the larger star appears to be killing its partner much more slowly. Over hundreds or thousands of years, the larger star has sucked in matter from the smaller star’s vicinity, while simultaneously blasting the small star with strobing beams of energy, which push even more matter away into space.

Someday, it’s possible that the larger star could devour the smaller one completely, lead study author Emma van der Wateren, a doctoral student at the Netherlands Institute for Radio Astronomy (ASTRON), told Live Science. But, before then, scientists hope to put this strange system to work. By monitoring the larger star’s remarkably steady pulses for sudden irregularities, the study authors hope this pulsar could help them detect rare ripples in the fabric of space-time(opens in new tab) known as gravitational waves.

“To detect gravitational waves, you need many, many very stable pulsars,” van der Wateren said. “And unlike earlier black widow pulsars that have been discovered, this system is very stable.”

Cannibal corpses

Scientists discovered star system J0610−2100 about 10,000 light-years from Earth in 2003, when they noticed its periodic pulsing with a radio telescope. Researchers pegged the system for a pulsar — a type of small, dense, collapsed star that rotates extremely quickly.

These dead stars are highly magnetized, blasting beams of electromagnetic radiation out of their poles as they spin. When one of those beams points toward Earth, the effect is like a lighthouse, with the light blinking on and off as the beam strobes past us. If the light blinks once every 10 milliseconds or less (like J0610−2100, which blinks every 3.8 milliseconds), then the star fits into an even rarer category, called a millisecond pulsar.

Many millisecond pulsars share their orbits with sun-like companion stars, which the pulsars slowly devour. As the pulsars gobble up the spinning disks of matter spewed by the companion star, they glow in X-ray radiation that can be spotted across the galaxy.

An illustration of a pulsar gobbling up matter from its companion star. In black widow pulsars, the companion star has been stripped down to one tenth the mass of Earth’s sun, or less.

And sometimes, a pulsar may take more than its fair share of matter from its companion. If a pulsar’s companion star has a mass smaller than one-tenth the mass of Earth’s sun, then that star system is called a black widow pulsar.

J0610−2100 was the third black widow pulsar ever detected — and seems to be one of the hungriest. The pulsar’s companion star measures just 0.02 solar masses, and completes an orbit around the pulsar every seven hours or so, the study found.

For their new paper, van der Wateren and her colleagues analyzed 16 years’ worth of radio telescope data from this cannibal star system. While the system is unmistakably a black widow pulsar, the team was surprised to find that it was missing a few signature quirks.

For example, the star system never showed what’s known as a radio eclipse — a nearly universal phenomenon in other black widow pulsars.

“Typically, for a portion of the binary orbit, the radio emissions from the pulsar completely disappear,” van der Wateren said. “This occurs when the companion star moves close to the front of the pulsar, and all this irradiated material coming off of the companion eclipses the pulse emission from the pulsar.”

Over 16 years, the star system also never showed any timing irregularities — sudden, tiny differences in the timing of a pulsar’s pulse compared to astronomers’ predictions.

Waves that move the universe

The absence of these two common phenomena is hard to explain, van der Wateren said. It could be that the line of sight on this pulsar is skewed so that radio eclipses just aren’t apparent to Earth-based telescopes, or perhaps the pulsar’s companion star isn’t being irradiated quite as strongly as other known pulsars that show these features. But whatever the case, this black widow system is incredibly stable and predictable — which makes it a perfect candidate for detecting gravitational waves, the researchers said.

These waves (first predicted by Albert Einstein) occur when the universe’s most massive objects interact — like when black holes or neutron stars collide. The waves ripple through time and space at light-speed, warping the fabric of the universe as they pass.

One way that astronomers hope to detect gravitational waves is by monitoring dozens of millisecond pulsars at once using systems called pulsar timing arrays. If every pulsar in the array suddenly experienced a timing irregularity around the same time, that could be evidence that something massive, like a gravitational wave, disrupted their pulses on the way to Earth.

“We have not detected gravitational waves in this way yet,” van der Wateren said. “But I think we are coming close.

That’s what makes the discovery of highly predictable black widow pulsars like this one so important, van der Wateren added.

Typically too temperamental because of their radio eclipses and timing irregularities, black widow pulsars are rarely good candidates for gravitational wave detection. But J0610−2100 might be an exception — and its mere existence suggests that there could be other suitable exceptions out there too. Like its arachnid namesake, this black widow’s cannibal bite may serve a greater purpose in the end.

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Todd

[Sean Robinson]

We can build a real, traversable wormhole … if the universe has extra dimensions

An artist’s depiction of a wormhole.

It may be possible to build a real, traversable wormhole, but only if our universe has extra dimensions, a team of physicists has found.

To make a wormhole, you need to glue together different parts of the universe, connecting them by a bridge or a tunnel, usually called a “throat.” This throat can be as big or as long as you want, but typically, you want it to be shorter than the normal distance to your destination. In Einstein’s theory of general relativity, making a wormhole is pretty straightforward: You just build a black hole and connect it to a white hole (which is the exact opposite of a black hole), and boom, there you have it: a tunnel through space-time.

Unfortunately, the biggest problem with wormholes is that they are fantastically unstable. As soon as they form, their enormous gravitational strengths (they are literally made of black holes, after all) rip them apart faster than the speed of light, which makes them rather useless as actual shortcuts through the universe.

The only known way to stabilize a wormhole is to use some form of exotic matter. Exotic matter can take the form of matter with negative mass, which doesn’t appear to exist in the universe, or some other scenario that violates what are known as the energy conditions of general relativity. The energy conditions simply state that everybody should experience positive energy, on average, pretty much everywhere they go. To stabilize a wormhole, however, a traveler would have to experience a region of negative energy. This negative energy would balance out the positive energy of the mass of the traveler, keeping the wormhole open as they passed through it.

There are some physical scenarios that lead to violations of some of the energy conditions some of the time. However, physicists do not know of a single instance in which all of the energy conditions are violated, on average, over long periods of time — which is exactly what you need to do to build a wormhole.

Your “brane” on physics

Gravity is extremely weak; it’s billions upon billions of times weaker than any other force of nature. This fact troubles many physicists, because when something is so strikingly different from the rest of the universe, there’s usually some interesting physical explanation behind it.

But we have no physical explanation for why gravity is so weak. One idea among theoretical physicists is that there’s more to the universe than meets the eye. Inspired by string theory’s concept of many extra spatial dimensions all wrapped up on themselves and compressed to submicroscopic scales, some theories propose that there are additional spatial dimensions to reality, besides the usual three.

In these theories, our three dimensions are just a “brane,” a relatively thin membrane that exists within a higher-dimensional “bulk.” Those extra dimensions aren’t necessarily huge; if they were, we would’ve noticed particles or planets appearing and disappearing from the extra dimension. But the extra dimensions might be larger than the minuscule dimensions of string theory — perhaps as big as a millimeter.

In this scenario, all the forces and particles of nature are then confined to the three-dimensional brane, while gravity alone has the privilege of traveling through the bulk. Thus, gravity could be just as strong as every other force, but it’s so heavily diluted among all the extra dimensions that it appears weak to our three-dimensional experience.

Through the wormhole

Because these brane-based ideas are attempts to understand gravity, they open up new opportunities to explore the nature of wormholes. Our knowledge of wormholes is governed by general relativity, but perhaps the presence of extra dimensions changes how general relativity operates, thus making wormholes possible, an Indian research team proposes in a new paper posted to the preprint database arXiv.

In the paper, the physicists explored whether it would be possible to build a wormhole in the “braneworld” model first proposed by physicists Lisa Randall and Raman Sundrum in 1999.

The authors of the new paper found that they could indeed build a stable, traversable wormhole in this brane-based model of gravity. Even better, they didn’t need any exotic matter to do it.

Although the team did find that this situation still violated the energy conditions of general relativity, they argued that this violation was a feature, not a bug. Instead of requiring some weird and exotic (and probably impossible) ingredient to build a wormhole, the nature of gravity in the extra spatial dimensions naturally gave rise to a violation of the energy conditions. Once those conditions were broken, wormholes became a natural consequence, they said.

The researchers even went so far as to suggest that if we were to ever directly observe or create a wormhole, this might indicate that the universe has more spatial dimensions than the usual three.

As with all theoretical work on the subject of wormholes, this is not the final word. Nobody knows if the Randall-Sundrum theory, or any other theory based on branes and extra dimensions, is correct. And nobody has a quantum theory of gravity — a theory of strong gravity at small scales — which would almost certainly change the calculations, perhaps to the point of once again eliminating the possibility of wormholes.

But this result is still interesting, as it joins a number of efforts to explore the edges of our understanding of gravity, taking general relativity to the absolute limits. Wormholes may or may not exist, but attempting to understand them will definitely increase our knowledge of the universe.

• This reply was modified 2 years, 9 months ago by Sean Robinson.

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Todd

[Rocket]

 

The blue arrows show the western section of the inner shell moving back towards the center of the nebula.

These guys are still “amazing”. I included a simple picture of what goes where and that is not West.

• This reply was modified 2 years, 9 months ago by Rocket.

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DavidM, Sean Robinson

Pow! Scientists spot new ‘micronova’ stellar explosion

Blink and you’ll miss it!

An international team of astronomers has observed and identified a new type of stellar explosion — a micronova.

Using the European Southern Observatory’s (ESO) Very Large Telescope (VLT), the researchers witnessed never-before-seen small thermonuclear explosions on white dwarf stars that lasted only a matter of hours. A white dwarf is the dense core of a star like our sun that has run out of fuel but does not explode, as a larger star would.

When a white dwarf is paired with a larger star, it can steal away hydrogen from its companion. Eventually, that hydrogen fuses into helium in a massive thermonuclear explosion called a nova. “Such detonations make the entire surface of the white dwarf burn and shine brightly for several weeks,” astronomer Nathalie Degenaar at the University of Amsterdam, the Netherlands, a co-author of a study describing the new micronova observations, said in an ESO press release.

An artist’s depiction of a micronova.

But when analyzing data from NASA’s Transiting Exoplanet Survey Satellite (TESS), researchers observed bright flashes that only lasted a few hours at a time on the surface of stars. Using ESO’s VLT, they confirmed that these small explosions were a new type of nova occurring in specific regions of white dwarfs.

“For the first time, we have now seen that hydrogen fusion can also happen in a localized way. The hydrogen fuel can be contained at the base of the magnetic poles of some white dwarfs, so that fusion only happens at these magnetic poles,” astronomer Paul Groot of Radboud University in the Netherlands, who co-authored the study, said in the statement. “This leads to micro-fusion bombs going off, which have about one-millionth of the strength of a nova explosion, hence the name micronova.”

Despite the term “micro” in their name, micronovas are still extremely powerful explosions. The researchers theorized that a single micronova burns through about 44,000,000 trillion pounds (20,000,000 trillion kilograms) — the equivalent of 3.5 billion Great Pyramids of Giza.

Though scientists have seen only three such events thus far, the researchers think micronovas may be happening regularly across the galaxy and simply evading detection. “These events may actually be quite common, but because they are so fast they are difficult to catch in action,” astronomer Simone Scaringi of Durham University in the U.K., who led the study, said in the statement.

As such, the team hopes to use large-scale surveys to find and study more micronovas.

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Todd

Sean Robinson wrote:

The researchers theorized that a single micronova burns through about 44,000,000 trillion pounds (20,000,000 trillion kilograms) — the equivalent of 3.5 billion Great Pyramids of Giza.

Finally they put it in terms I can understand.

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DavidM, Rocket, Sean Robinson, Todd

[Sean Robinson]

‘Groundbreaking’ Milky Way results from telescope network behind 1st black hole image coming soon

We’ll find out more May 12 from the same telescope group that imaged a black hole in April 2019.

There’s a ‘groundbreaking’ result coming concerning the supermassive black hole at the center of the Milky Way.

Earth’s planet-scale observatory network, best known for creating the first-ever image of a black hole, is ready to report new results about the center of our Milky Way galaxy.

More information about the “groundbreaking” research on our galaxy will be presented on May 12 at 9 a.m. EDT (1300 GMT). Although the announcement is two weeks away, it’s likely that the discovery relates to the supermassive black hole that lurks at the center of the Milky Way. Called Sagittarius A*, this behemoth has been a key target for the Event Horizon Telescope (EHT) since 2017.

___________________________________________________________

Largest treasure trove of exocomets to date found in alien solar system

NASA’s planet-finding TESS mission has spotted 30 comets around a young star, giving astronomers fresh insight into the processes that form comets and planets.

An artist’s impression of comets hurtling towards Beta Pictoris.

Thirty alien comets have been spotted transiting the young star Beta Pictoris, their long tails lighting up the skies of the fledgling planets forming there.

The comet discovery has been made using NASA’s Transiting Exoplanet Survey Satellite (TESS), which watches for dips in starlight as planetary bodies pass in front of — or transit — their star. Beta Pictoris, which is 63.4 light years away, is home to a dusty planet-forming disk that was discovered back in 1983 by IRAS, the Infrared Astronomy Satellite. The disk contains at least two planets, both gas giants, and spectral observations gathered as long ago as 1987 suggested evidence for comets (or ‘falling evaporating bodies’ as they were referred to at the time) releasing dust and gas into the disk.

• This reply was modified 2 years, 8 months ago by Sean Robinson.

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Todd

Dark Energy Camera spies ‘galactic ballet’ of galaxies in stunning space photo

This image shows a wider view of the interacting galaxies NGC 1512 and NGC 1510 as seen by the Dark Energy Camera on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile operated by the National Science Foundation’s NOIRLab.

One of the most powerful cameras in the world just photographed two distant galaxies entwined in what’s been described as a “galactic ballet.”

Part of the National Science Foundation’s (NSF) National Optical-Infrared Astronomy Research Laboratory (NOIRLab), the Dark Energy Camera on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile trained its lenses on the Horologium constellation some 60 million light-years from Earth. There, it captured an image of galaxies NGC 1512 and NGC 1510, which are ensnared in each other’s gravitational pull.

NGC 1512 is a barred spiral galaxy not dissimilar to our own Milky Way, while NCG 1510 is far smaller — a dwarf galaxy. The two have been circling one another for some 400 million years, their shapes warping with each pass.

The Dark Energy Camera that photographed the galaxies is one of the most powerful wide-field imaging instruments on the planet. It has a 13-foot-wide (four-meter-wide) mirror and a 3.3-foot (one-meter-wide) corrective lens — one of five lenses on the device.

The Dark Energy Camera was originally built to complete the Dark Energy Survey, a mission run by the U.S. Department of Energy’s Fermi National Accelerator Laboratory. More than 400 scientists from seven countries participated in the survey, which imaged some 300 million galaxies between 2013 to 2019, with the goal of studying enigmatic dark energy.

Though that mission has ended, scientists still use the Dark Energy Camera to image distant galaxies, including NGC 1512 and NGC 1510. When the two galaxies’ dance is complete — which won’t be any time soon — NGC 1512 will consume its smaller companion to create a new, merged galaxy.

The full view of the interacting galaxy pair NGC 1512 and NGC 1510 take center stage in this image from the Dark Energy Camera on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile.

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Rocket, Todd

Sean Robinson wrote:

More information about the “groundbreaking” research on our galaxy will be presented on May 12 at 9 a.m. EDT (1300 GMT).

Less than 10 hours now…

Behold! This is the first photo of the Milky Way’s monster black hole Sagittarius A*

Say hello to Sagittarius A*.

The Event Horizon Telescope has captured a historic first image of the supermassive black hole at the center of our galaxy.

The image, which was taken in the light of submillimeter radio waves, confirms that there is a black hole in the heart of the Milky Way that is feeding on a trickle of hydrogen gas.

“Until now, we didn’t have the direct picture to prove that this gentle giant in the center of our galaxy is a black hole,” Feryal Özel, an astrophysicist at the University of Arizona, said during a National Science Foundation news conference held Thursday (May 12). “It shows a bright ring surrounding the darkness, and the telltale sign of the shadow of the black hole.”

An image of the supermassive black hole at the center of the Milky Way, a behemoth dubbed Sagittarius A*, revealed by the Event Horizon Telescope on May 12, 2022.

“This is an astounding achievement,” Ryan Hickox, an astrophysicist at Dartmouth College who is not a member of the EHT team, told Space.com. “I think I speak for a large number of my astronomy colleagues when I say how remarkably grateful we are.”

In 2019, the Event Horizon Telescope (EHT) made headlines when it succeeded in producing the first ever image of the event horizon of a black hole, specifically the black hole at the center of the active elliptical galaxy Messier 87. At the same time as it gathered the data that became that image, the EHT also performed observations of Sagittarius A*, which is the name given to the Milky Way’s supermassive black hole. However, producing an image of Sagittarius A* proved more difficult than for M87.

For one thing, Earth’s water-laden atmosphere can absorb the submillimeter radio waves that the EHT relies on. Moreover, gas and dust in the intervening 27,000 light-years between us and Sagittarius A* can scatter the submillimeter waves and blur the image. Lastly, whereas M87’s black hole has a voracious appetite and appears bright because it is consuming a lot of gas, the flow of material onto Sagittarius A* is far more feeble, meaning it is much fainter.

“Getting to this image wasn’t an easy journey,” Özel said. “It took several years to refine the image and confirm what he had.”

Black holes are the densest objects in the universe, and their gravity is irresistible, to the extent that within a certain distance of a black hole, not even light can escape. Scientists call this “point of no return” the event horizon.

The EHT is able to see light, in the form of radio waves, from hot gas swirling around the edge of the event horizon. The black hole feeds from the material within its immediate environment, whether gas clouds, asteroids or even stars that might wander too close and be ripped apart by gravitational tides.

However, Sagittarius A* is being starved.

“We only see a trickle of material making it all the way to the black hole,” Harvard astrophysicist Michael Johnson said during the NSF press conference. “In human terms, it would be like eating just one grain of rice every million years.”

Why the accretion of gas onto Sagittarius A* is so slow has been a puzzle for many years, Nobel Prize laureate Andrea Ghez, an astrophysicist at the University of California, Los Angeles, told Space.com. “There’s a lot of mysteries associated with the accretion flow, in terms of why it is so faint,” she added.

A collage shows the first image of the black hole at the center of the Milky Way at its location on the sky.

Ghez shared the 2020 Nobel Prize in Physics for measuring the mass of Sagittarius A* by observing the motions of stars orbiting close to it. Ghez and her team calculated a mass that was 4.3 million times the mass of our sun.

Since the size of the event horizon is connected to the mass of the black hole, it was therefore possible to make a prediction, Ghez said. “The power of imaging the black hole’s ring is that, if you know the mass and distance to the black hole — in other words, the size of the event horizon — then you can use that to compare to theory.”

The new image shows that the size of Sagittarius A*’s event horizon is 51.8 microarcseconds on the sky.

“Our image is in very close agreement with theoretical predictions,” said Özel, who described it as the biggest test of Einstein’s theory of general relativity ever made, noting that the theory passed with flying colors.

“It’s a great laboratory for trying to understand how gravity works in the vicinity of a supermassive black hole,” Ghez said.

A comparison of Event Horizon Telescope views of the black holes at the center of the galaxy M87, on the left, and of the one in the Milky Way, at right.

More uncertain are our explanations for the turbulence seen in the gas ring. The black hole of M87 is much larger than Sagittarius A*, and therefore it takes days for changes to become apparent, whereas Sagittarius A* is much smaller and, as material whips around it, the brightness of the ring can change in mere minutes.

“It is teeming with activity, always gurgling with turbulent energy,” Johnson said of the ring around the event horizon.

To try to explain what they were seeing, the EHT team — which is made up of more than 300 researchers across 80 institutions — performed more than 5 million supercomputer simulations to try and find one that was a match for what they observed.

“We were left with only a handful of simulations that share the features that we observe, but none of them explain all the features,” Johnson said. In particular, the simulations all predicted more and faster variability than what was actually seen, and could relate to how gas is accreting onto the ring, or how magnetic fields are interacting with that inflow.

Reacting to the image, Hickox said that “it’s just remarkable to see an image of the black hole that we know best, and to see the ring and measure the shadow size as accurately as they did.”

Furthermore, this image of Sagittarius A* can now act as a template for other quiescent black holes in the universe.

“This black hole is more typical of the overall set of black holes in the universe than the one in M87,” Hickox said. “If you were just to take a picture of a random supermassive black hole in a galaxy somewhere in the universe, then this is what it would look like.”

This image of Sagittarius A*, and of the black hole in M87 before it, has been made possible through the magic of a technique known as Very Long Baseline Interferometry, which allows astronomers to combine data from radio telescopes all across the world as though they were one large telescope, effectively making the EHT the largest telescope on Earth.

At the time when the observations were made, the network consisted of eight telescopes (including one, the South Polar Telescope, that was too far south to study M87), although three more have since been added to the network. The eight-telescope configuration means that the EHT’s maximum baseline — which is equivalent to a telescope’s aperture — for observing Sagittarius A* was 6,650 miles (10,700 kilometers) across.

Future observations will now focus on getting sharper images to better understand the physics of turbulence in the ring around the black hole, as well as how the black hole affects the environment of the galaxy around it.

“This is driving us to make even better measurements and sharper images,” Johnson said.

Sagittarius A* and the black hole in M87 were the EHT’s top two targets because of their relatively large angular size on the sky. Supermassive black holes in other galaxies appear far smaller on the sky, beyond even the abilities of the EHT to image their event horizon. To be able to do so would require a lengthening of the baseline — that is, to widen the EHT’s aperture — between the two widest points in the EHT’s network. In this sense, the resolution that the EHT can achieve is limited by the size of Earth, but Hickox says there are possibilities beyond Earth.

“I’ve heard talk about potentially having a space-based addition to the EHT, which would significantly increase the overall angular resolution,” he told Space.com. “That would be an exciting step forward.”

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Todd

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Sean Robinson

Sean Robinson wrote:

An image of the supermassive black hole at the center of the Milky Way, a behemoth dubbed Sagittarius A*, revealed by the Event Horizon Telescope on May 12, 2022.

Whoopdie-f-inghoo, Muse had one in 2006.

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Sean Robinson

Voyager 1 glitch? NASA working to understand strange data from venerable probe

An artist’s depiction of the Voyager 1 spacecraft.

Spending 45 years traversing the solar system really does a number on a spacecraft.

NASA’s Voyager 1 mission launched in 1977, passed into what scientists call interstellar space in 2012 and just kept going — the spacecraft is now 14.5 billion miles (23.3 billion kilometers) away from Earth. And while Voyager 1 is still operating properly, scientists on the mission recently noticed that it appeared confused about its location in space without going into safe mode or otherwise sounding an alarm.

“A mystery like this is sort of par for the course at this stage of the Voyager mission,” Suzanne Dodd, project manager for Voyager 1 and its twin, Voyager 2, at NASA’s Jet Propulsion Laboratory in California, said in a statement.

“The spacecraft are both almost 45 years old, which is far beyond what the mission planners anticipated,” Dodd added. “We’re also in interstellar space — a high-radiation environment that no spacecraft have flown in before.”

The glitch has to do with Voyager 1’s attitude articulation and control system, or AACS, which keeps the spacecraft and its antenna in the proper orientation. And the AACS seems to be working just fine, since the spacecraft is receiving commands, acting on them and sending science data back to Earth with the same signal strength as usual. Nevertheless, the AACS is sending the spacecraft’s handlers junk telemetry data.

The NASA statement does not specify when the issue began or how long it has lasted.

The agency says that Voyager personnel will continue to investigate the issue and attempt to either fix or adapt to it. That’s a slow process, since a signal from Earth currently takes 20 hours and 33 minutes to reach Voyager 1; receiving the spacecraft’s response carries the same delay.

The twin Voyager 2 probe, also launched in 1977, is behaving normally, NASA said. The power the twin spacecraft can produce is always falling, and mission team members have turned some components off to save juice — measures they hope will keep the probes working through at least 2025.

“There are some big challenges for the engineering team,” Dodd said. “But I think if there’s a way to solve this issue with the AACS, our team will find it.”

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Sean Robinson wrote:

Voyager 1 glitch? NASA working to understand strange data from venerable probe

An artist’s depiction of the Voyager 1 spacecraft.

Spending 45 years traversing the solar system really does a number on a spacecraft.

NASA’s Voyager 1 mission launched in 1977, passed into what scientists call interstellar space in 2012 and just kept going — the spacecraft is now 14.5 billion miles (23.3 billion kilometers) away from Earth. And while Voyager 1 is still operating properly, scientists on the mission recently noticed that it appeared confused about its location in space without going into safe mode or otherwise sounding an alarm.

“A mystery like this is sort of par for the course at this stage of the Voyager mission,” Suzanne Dodd, project manager for Voyager 1 and its twin, Voyager 2, at NASA’s Jet Propulsion Laboratory in California, said in a statement.

“The spacecraft are both almost 45 years old, which is far beyond what the mission planners anticipated,” Dodd added. “We’re also in interstellar space — a high-radiation environment that no spacecraft have flown in before.”

The glitch has to do with Voyager 1’s attitude articulation and control system, or AACS, which keeps the spacecraft and its antenna in the proper orientation. And the AACS seems to be working just fine, since the spacecraft is receiving commands, acting on them and sending science data back to Earth with the same signal strength as usual. Nevertheless, the AACS is sending the spacecraft’s handlers junk telemetry data.

The NASA statement does not specify when the issue began or how long it has lasted.

The agency says that Voyager personnel will continue to investigate the issue and attempt to either fix or adapt to it. That’s a slow process, since a signal from Earth currently takes 20 hours and 33 minutes to reach Voyager 1; receiving the spacecraft’s response carries the same delay.

The twin Voyager 2 probe, also launched in 1977, is behaving normally, NASA said. The power the twin spacecraft can produce is always falling, and mission team members have turned some components off to save juice — measures they hope will keep the probes working through at least 2025.

“There are some big challenges for the engineering team,” Dodd said. “But I think if there’s a way to solve this issue with the AACS, our team will find it.”

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Sun busts out trio of moderate solar flares that might herald more activity

Keep an eye on sunspot AR3014.

A trio of moderate flares blasted off from the sun on Thursday (May 19), and there might be more in store.

The solar flares come amid a noticeable uptick in solar activity in recent months. SpaceWeather.com says a storm is swirling around sunspot AR3014, to the extent that the region is “literally seething.” As the magnetic lines twist and tangle, they may snap and send a coronal mass ejection towards our planet.

Forecasters with the National Oceanic and Atmospheric Administration (NOAA), wrote SpaceWeather, “estimate a 35% chance of M-class solar flares and a 15% chance of X-flares on May 19.”

An M-class solar flare that occurred on May 19, 2022.

X-flares are the strongest possible class of flares, and should they erupt from this particular sunspot, they would be “geoeffective” due to the sunspot facing Earth. Flares are often accompanied by CMEs, which would arrive a little later.

So far scientists have seen a flurry of X-rays associated with the M-class flares, as captured by NOAA’s Geostationary Operational Environmental Satellite-16 (GOES-16) satellite that monitors the Americas.

The sun seems to have woken up in early 2022 as it moves towards the peak of its solar cycle in 2025. It has fired off numerous flares in recent weeks, including a few X-class ones.

An outburst from the sun that occurred on May 19, 2022.

Usually the CMEs following flares are harmless and just create colorful auroras high up in the atmosphere. But in some very rare cases, they can disrupt satellites, power lines and other infrastructure. So scientists keep gazing at the sun to assess its dynamics and to predict space weather as best as possible.

In the United States, for example, both NASA and NOAA look at the sun all the time. A sungazing mission known as Parker Solar Probe is sweeping in close to look at the corona or superheated outer region of the sun, as other satellites watch from further afield to gain context.

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Why have aliens never visited Earth? Scientists have a disturbing answer

Advanced civilizations could be doomed to stagnation or death

An artist’s image of an alien starship as viewed from a planet’s surface.

Why has humanity never been visited by aliens (that we know of)? The question has confounded scientists for decades, but two researchers have come up with a possible — and disturbing — explanation: Advanced civilizations could be doomed to either stagnate or die before they get the chance.

The new hypothesis suggests that, as space-faring civilizations grow in scale and technological development, they eventually reach a crisis point where innovation no longer keeps up with the demand for energy. What comes next is collapse. The only alternative path is to reject a model of “unyielding growth” in favor of maintaining equilibrium, but at the cost of a civilization’s ability to expand across the stars, the researchers said.

The argument, published on May 4 in the journal Royal Society Open Science, attempts to find a resolution to the Fermi Paradox. Taking its name from the casual lunchtime musings of Nobel Prize-winning physicist Enrico Fermi, the paradox draws attention to the contradiction between the immense scope and age of the universe — two things that suggest the universe should be teeming with advanced alien life — and the lack of evidence that extraterrestrials exist anywhere in sight. “So where is everybody?” Fermi is thought to have remarked.

The researchers of the new study say they may have the answer.

“Civilizations either collapse from burnout or redirect themselves to prioritizing homeostasis, a state where cosmic expansion is no longer a goal, making them difficult to detect remotely,” astrobiologists Michael Wong, of the Carnegie Institution for Science, and Stuart Bartlett, of the California Institute of Technology, wrote in the study. “Either outcome — homeostatic awakening or civilization collapse — would be consistent with the observed absence of [galactic-wide] civilizations.”

The pair came to their hypothesis by researching studies of the “‘superlinear”‘ growth of cities. These studies suggested that cities increase in size and energy consumption at an exponential rate as their populations grow, inevitably leading to crisis points — or singularities — that cause rapid crashes in growth, followed by an even more precipitous, potentially civilization-ending, collapse.

“We hypothesize that once a planetary civilization transitions into a state that can be described as one virtually connected global city, it will face an ‘asymptotic burnout,’ an ultimate crisis where the singularity-interval time scale becomes smaller than the time scale of innovation,” they wrote.

These close-to-collapse civilizations would be the easiest for humanity to detect, the researchers suggest, as they would be dissipating large amounts of energy in a “wildly unsustainable” way. “This presents the possibility that a good many of humanity’s initial detections of extraterrestrial life may be of the intelligent, though not yet wise, kind,” the researchers wrote.

To avert their doom, civilizations could undergo a “homeostatic awakening,” redirecting their production away from unbounded growth across the stars to one that prioritizes societal wellbeing, sustainable and equitable development and harmony with their environment, the researchers suggest. While such civilizations may not completely abandon space exploration, they would not expand on scales great enough to make contact with Earth likely.

The researchers point to a few of humanity’s “mini-awakenings” that addressed global crises on Earth, such as the reduction of global nuclear arms stockpiles from 70,000 warheads to below 14,000; the halting of the once-growing hole in Earth’s ozone layer by banning chlorofluorocarbon emissions; and the 1982 international whaling moratorium.

The scientists stress, however, that their suggestion is simply a hypothesis, taken from the observation of laws that seem to govern life on Earth, and is designed to “provoke discussion, introspection and future work.”

Their proposal joins a bountiful crop of other scientific and popular suggestions as to why we’ve never made direct contact with celestial visitors. These include the numerous practical challenges presented by interstellar travel; that aliens may actually be visiting in secret; or that aliens arrived to Earth too soon (or humans too early) in the life of the universe for direct contact.

Another hypothesis, published April 4 in The Astrophysics Journal, suggests that the sheer scale of the universe means it could take as long as 400,000 years for a signal sent by one advanced species to be received by another — a timescale that’s far greater than the brief period humans have been able to scan the skies.

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Todd

Just in case you were curious:

https://www.theplanetstoday.com/

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Hubble telescope spots stunning ‘Hidden Galaxy’ hiding behind our own Milky Way

If it weren’t for all the interstellar matter in the way, IC 342 would be one of the brightest galaxies in the sky.

Behold the “Hidden Galaxy” coming into view.

This glorious Hubble Space Telescope image showcases spiral galaxy IC 342, also known as Caldwell 5. No matter what you call this galaxy, scientists have had some difficulty observing it due to obstacles in the way, earning it its “hidden” nickname, according to NASA.

“It appears near the equator of the Milky Way’s pearly disk, which is crowded with thick cosmic gas, dark dust, and glowing stars that all obscure our view,” NASA wrote in a May 11 statement(opens in new tab).

more pics and text in link…

This new view of the spiral galaxy IC 342, also known as Caldwell 5, as seen by the Hubble Space Telescope was released by NASA on May 11, 2022. Seen here is a zoomed-in view.

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Spectacular Hubble image captures ‘grand spiral’ galaxy

This area is full of star-forming regions.

This sky full of stars from the Hubble Space Telescope is, to quote Coldplay, a heavenly view.

It’s a galactic image from the telescope’s Wide Field Camera 3 and Advanced Camera for Surveys, focusing on NGC 3631. The spiral arms of the “Grand Design Spiral”, as this object is nicknamed, are absolutely brimming with starbirth.

The color blue represents visible wavelengths of blue, and orange is showcasing infrared or heat-rich areas that are otherwise difficult to see due to dust in the way.

more pics and text in link…

This image from NASA’s Hubble Space Telescope features the Grand Design Spiral, more officially known as NGC 3631.

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Todd

A mysterious intergalactic force is pushing against the Milky Way

Meet the dipole repeller.

An artist’s depiction of superclusters in the universe.

It sounds like the premise of a bad sci-fi movie: There’s some mysterious entity, beyond the boundaries of our galaxy, that is pushing against us with incredible force. We don’t know exactly what it is, and we don’t know how long it’s been there. But we do know its name: the dipole repeller.

The name may be a bit dorky, but it’s a very real thing. It’s also nothing to worry about — just a normal consequence of the usual process of structure formation that’s been happening in the universe for [checks watch] 13.8 billion years.

How to build a supercluster

To set the stage for the dipole repeller, we need to go big. And not your usual astronomy-big, with galaxy-scale events and energies. No, we have to go really big.

Beyond the Milky Way sit a few other galaxies. There’s Andromeda, 2.5 million light-years away, which everyone knows and loves. There’s also Triangulum, which nobody really cares about. Our three galaxies and a few dozen dwarf galaxies combine to form the Local Group, which is a very unassuming name for a structure a few million light-years across.

The nearest big deal to our Local Group is the Virgo Cluster, a massive ball of over a thousand galaxies sitting 60 million light-years away. Our Local Group and other groups in this patch of space aren’t part of the Virgo Cluster itself; rather, they belong to a greater structure known as the Virgo Supercluster.

Here’s where things get a little tricky. Groups and clusters have decent, understandable definitions: They are gravitationally bound. Superclusters aren’t; they’re just collections of galaxies that are larger than clusters but smaller than, say, the entire universe. Different cosmologists can apply various definitions of the word “supercluster” and get a range of segmentations.

It’s like a population census trying to define a metro area: Sure, there are the city limits, but what about all the people living near a major city and working in it? Where, exactly, does it stop?

A story of superclusters and voids

Despite these varied definitions, we can draw some general outlines. The Virgo Supercluster appears to be just one branch of an even larger supercluster called Laniakea. Other superclusters surround and connect with Laniakea, like the Shapley Supercluster, the Hercules Supercluster and the Pavo-Indus Supercluster. Each of these massive structures is hundreds of millions of light-years long.

The superclusters are like the foam you see when you add too much soap to your bath. We’re just giving different parts of that foam network cool names. But between all those bits of foam are vast, empty regions. In your bath, those empty pockets are the soap bubbles themselves. In cosmology, they’re the great cosmic voids.

Every supercluster defines the edge of a corresponding cosmic void. There’s the Sculptor Void, the Canis Major Void, the Boötes Void and more. Each of these voids is a vast expanse of not much at all — empty cosmological wastelands containing nothing but a few straggling galaxies, like oasis towns in a desert. The largest of these voids, like Boötes, are over 300 million light-years in diameter.

That’s a whole lot of nothing.

The dipole repeller

It’s actually kind of hard to map our local vicinity of the universe (and by “local,” I mean everything within about a billion light-years). That’s because all the dust in the Milky Way obscures our view, and we have to resort to fancy astronomical tricks, like sensitive infrared and radio surveys, to get a sense of what’s going on.

It’s through these tricks that cosmologists were able to identify the Shapley Supercluster, Laniakea’s nearest neighbor. The mass of the Shapley Supercluster is so impressive that it exerts a gravitational pull on this entire region of space. Every galaxy, including the Milky Way, is moving in that direction.

But the estimated mass of the Shapley Supercluster may not be quite enough to account for our velocity. In addition to the pull of the Shapley, there has to be something else, a push, coming from the opposite direction.

This is the dipole repeller, a hypothetical void (and possible supervoid) that sits on the opposite side of the Milky Way as the Shapley Supercluster. As the Shapley pulls us with its massive gravity, the dipole repeller pushes us with its massive … nothingness.

How does that work?

Think about it this way. Let’s say you carve out a hole in something — a block of wood, a chunk of cheese or the large-scale structure of the universe. If you place something near that hole, it will feel a gravitational tug in every direction except the hole. So it will tend to move away from the hole, because that hole can’t contribute its own gravitational influence.

It will appear as if the hole — or void — is repelling the object, even though it’s only sitting there, literally doing nothing.

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James Webb Space Telescope will study two strange ‘super-Earths’

Officials promise geology ‘from 50 light-years away.’

Artist’s impression of exoplanet 55 Cancri e.

The James Webb Space Telescope plans to explore strange, new rocky worlds in unprecedented detail.

The telescope’s scientific consortium has an ambitious agenda to study geology on these small planets from “50 light-years away”, they said in a statement Thursday (May 26). The work will be a big stretch for the new observatory, which should exit commissioning in a few weeks.

Rocky planets are more difficult to sight than gas giants in current telescope technology, due to the smaller planets’ relative brightness next to a star, and their relatively tiny size. But Webb’s powerful mirror and deep-space location should allow it to examine two planets slightly larger than Earth, known as “super-Earths.”

Neither of these worlds is habitable as we know it, but investigating them could still be a proving ground for future in-depth studies of planets like our own. The two planets Webb officials highlighted include the super-hot, lava-covered 55 Cancri e, and LHS 3844 b, which lacks a substantial atmosphere.

Illustration comparing two rocky exoplanets to Earth and Neptune. In order of appearance, from left to right, are Earth (based on Deep Space Climate Observatory data), LHS 3844 b (an illustration), 55 Cancri e (an illustration) and Neptune (based on Voyager 2 data).

55 Cancri e orbits its parent star at a tight 1.5 million miles (2.4 million km), about four percent of the relative distance between Mercury and the sun.

Circling its star only once every 18 hours, the planet has blast furnace surface temperatures above the melting point of most types of rocks. Scientists also assumed the planet is tidally locked to the star, meaning one side always faces the scorching sun, although observations from NASA’s Spitzer Space Telescope suggest the hottest zone might be slightly offset.

Scientists say the offset heat might be due to a thick atmosphere that can move heat around the planet, or because it rains lava at night in a process that removes heat from the atmosphere. (The nighttime lava also suggests a day-night cycle, which might be due to a 3:2 resonance, or three rotations for every two orbits, that we see on Mercury in our own solar system.)

Two teams will test these hypotheses: one led by research scientist Renyu Hu of NASA’s Jet Propulsion Laboratory will examine the planet’s thermal emission for signs of an atmosphere, while a second team led by Alexis Brandeker, an associate professor from Stockholm University, will measure heat emittance from the lit side of 55 Cancri e.

LHS 3844 b is also a close orbiter, moving around its parent star just once every 11 hours. The star, however, is smaller and cooler than that of 55 Cancri e. So the planet’s surface is likely much cooler, and Spitzer observations have shown there is likely no substantial atmosphere present on the planet.

A team led by astronomer Laura Kreidberg at the Max Planck Institute for Astronomy hope to catch a signal of the surface using spectroscopy, in which different wavelengths of light suggest different elements. Thermal emission spectrums of the planet’s daylight side will be compared to known rocks like basalt and granite to see if they can deduce a surface composition.

The two investigations “will give us fantastic new perspectives on Earth-like planets in general, helping us learn what the early Earth might have been like when it was hot like these planets are today,” Kreidberg said in the same statement.

Webb is now working through latter-stage commissioning procedures like tracking targets in the solar system and moving between hotter and colder attitudes to test the strength of its mirror and instrument alignment. The $10 billion observatory should finish its commissioning around June or so and move into its Cycle 1 of observations shortly afterwards.

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4 big Milky Way mysteries the next Gaia mission data dump may solve

“You really get to know the stars.”

This image shows the paths of 40,000 stars located within 326 light-years of the solar system over the next 400,000 years, based on measurements and projections from the European Space Agency’s Gaia spacecraft.

A treasure trove of data is set to answer some big questions about our galaxy.

The data, compiled by the European Space Agency’s Gaia mission, contains an unprecedented amount of information about more than 1 billion of the brightest objects in the sky. Astronomers hope the new data, which will be released June 13, will help solve some major mysteries about the birth and life of the Milky Way and the stars in it.

The Gaia mission launched in 2013 and is known for creating the most detailed map of the Milky Way by charting the precise positions, distances and velocities of nearly 2 billion stars. The upcoming data set will add a new dimension: It will reveal the chemical compositions of tens of millions of stars, allowing astronomers to answer important questions.

Hovering around Lagrange Point 2 (not too far from another groundbreaking mission, the James Webb Space Telescope), Gaia scans the entire sky about every two months. The 2 billion celestial objects the telescope sees make up only about 1% of the total stars in the Milky Way. But with the help of sophisticated computer algorithms and a lot of scientific knowledge, astronomers can extrapolate those measurements to learn about the galaxy as a whole.

Here are some of the most fascinating mysteries the Milky Way explorers are eager to crack with the new data.

1. Where do stars come from?

By measuring the precise positions, distances and velocities of vast quantities of stars, Gaia does much more than map the Milky Way as it is today. Because objects in the universe follow the rules of physics, astronomers can model the past trajectories of those stars and essentially play the movie of the Milky Way backward and forward millions, or even billions, of years. But that was already possible with the previously released data. With the new data set, astronomers will be able to look for more.

For the first time, the Gaia mission team will release what they call “astrophysical parameters” for half a billion stars. These parameters, derived from the light spectra of the stars measured by Gaia (which are essentially the fingerprints of how these stars absorb light), reveal information about the chemical composition, mass, age, temperature and brightness of each of the measured stars. And that is a big deal, Gaia project scientist Jos de Bruijne told Space.com.

The Milky Way has four spiral arms, but astronomers still debate about their sizes and positions.

“You will really get to know the stars,” De Bruijne said. “They basically tell you who they are. It’s like having an anonymous group of 500 million people and now you get to know every single one of them — their names, how old they are, where they came from.”

For 30 million of these stars, Gaia measured the chemical composition of stellar atmospheres, which is identical to the chemical composition of the molecular clouds that these stars were born in billions of years ago, De Bruijne said. By combining the information about chemical composition with the modeling of the stellar trajectories, astronomers will be able to track groups of stars to their birthplaces inside (but also outside) the Milky Way.

“It’s really unique that we now can do this with such a high number of stars,” De Bruijne said. “That’s something that is otherwise really difficult and expensive to do with ground-based telescopes, as it takes a lot of time.”

2. How does the galaxy “hang” together?

Although Gaia has been scanning the Milky Way since 2014, there is still a lot astronomers don’t understand about the galaxy. Studying our galactic home is not an easy task. Because we are inside the galaxy, we cannot “see the forest for the trees.” It is impossible even for Gaia to peer through the thick dust and gas clouds obscuring the Milky Way’s center (where the recently photographed supermassive black hole Sagittarius A* lurks) to the other side of the galactic disk.

But through the gradual improvements in Gaia data — and with the help of other observation techniques, such as radio astronomy — the big picture is coming together, piece by piece. That means we’re getting closer to solving some of the great puzzles, including the distribution of dark matter in the galaxy.

“All the stuff in the galaxy is exerting gravity at every star, and this gravity determines how fast the star moves,” De Bruijne said. “So by measuring motions of stars, you also probe the matter distribution in the Milky Way. And that is really important for figuring out how the galaxy hangs together.”

One of the lingering uncertainties related to the distribution of stars in the Milky Way is the galaxy’s trademark spiral structure. Astronomers mostly agree that the Milky Way has four spiral arms, the dense twisting streams of stars and gas that appear to emanate from the galaxy’s center. But there are quite a few points of contention around these spiral arms: Astronomers still debate the size and prominence of the individual arms, as well as their exact position in the Milky Way’s disk. The new data might help reveal the spiral structure with better clarity.

“With the astrophysical parameters that we now have, we can directly create samples of stars for specific science cases,” De Bruijne said. “We know that the spiral arms are mostly made of young stars. It’s where stars form. So, with the new data, we can look, for instance, at stars that are no older than 100 million years.” (In stellar terms, 100 million years is infancy. For comparison, our sun is 4.6 billion-year-old and will die in 5 billion years.)

Again, Gaia doesn’t only see the spiral arms as they are today; it allows astronomers to model the arms’ evolution into the past and the future.

With the new data, astronomers will be able to look farther away from the sun, thus directly sampling a larger portion of the galaxy’s spiral arms, Anthony Brown, an astronomer at Leiden University in the Netherlands and chair of the Gaia Data Processing and Analysis Consortium, told Space.com. Still, understanding the galaxy as a whole will remain a challenge.

3. What happened in the Milky Way’s “childhood”?

The Milky Way has grown over billions of years by devouring smaller galaxies that fall into its orbit.

Gaia measurements enable astronomers to perform what they call “galactic archaeology.” By reconstructing the trajectories of millions of stars, they can learn about events that happened in the distant past, billions of years ago. These events involve cataclysmic collisions with other galaxies, the ripples of which can be observed in the galaxy to this day.

One of the most famous discoveries that came out of the earlier Gaia data releases was the collision with a smaller galaxy called Gaia Enceladus, which happened 8 billion to 11 billion years ago. At that time, the Milky Way was much smaller than it is today, and when it devoured the smaller intruder, it experienced considerable upheaval. Brown said the collision with Gaia Enceladus was “the last significant merger that the Milky Way underwent” in its violent childhood. He hopes that with the new data set, astronomers will be able to look further back into the galaxy’s history and trace some of the even earlier collisions.

“We have already seen some authors trying to look more than 10 billion years into the past at the first hints of the Milky Way’s formation, some 12 [billion] or 13 billion years ago,” Brown said. “With the new release, we should be able to do this much better, thanks to the astrophysical information that we will be releasing. Now that we know the ages and the chemical compositions of stars, we can figure out the time order in which events happened, and we can also see where stars originally came from.”

The Milky Way continues to eat up smaller galaxies to this day. The two dwarf galaxies known as the Large Magellanic Cloud and the Small Magellanic Cloud, which orbit around the outskirts of the Milky Way, will one day be completely swallowed up by the Milky Way, models show. The remnants of other dwarf galaxies can be traced in the Gaia data in the form of stellar streams scattered over the Milky Way’s halo, Brown said.

Just as it emerged from violent collisions, the Milky Way will one day die a violent death. About 4.5 billion years from now, the Milky Way will collide with its nearest large galactic neighbor, the Andromeda galaxy. This collision is expected to happen at about the same time as the death of the sun, so humankind is unlikely to be around to see it. The new Gaia data release may, in fact, shed some light on this cataclysmic event, Brown said.

4. What’s wrong with the Milky Way’s disk?

The structure of the Milky Way with its rotating warped galactic disk.

Gaia’s earlier data revealed that the Milky Way’s disk is warped, rather than flat. It also wobbles like a spinning top as it rotates around the center of the galaxy. Astronomers think this wobble resulted from a not-so-distant galactic crash.

Brown hopes the new data will shed more light on this disturbance and its origins. The upcoming data release will contain information about the motion of more than 30 million stars in Gaia’s line of sight — that is, how fast they move toward or away from the telescope, or the so-called radial velocity. The prior releases contained radial velocities of only 7 million stars. The more information astronomers have, the finer the details their analysis tools can reveal about the galaxy.

“We can try to measure [the disturbance] in different locations in the galaxy or look at how it affects certain types of stars,” Brown said. “And this tells us a lot about what, exactly, caused the disturbance of the Milky Way’s disk. This is the kind of thing you can start doing with this much more expanded data sample.”

And more is yet to come

Gaia is currently the scientific mission that generates the most scientific papers, and according to De Bruijne, the best is still to come. The June 13 data dump will also contain the largest-ever set of information about binary star systems in the Milky Way, and De Bruijne expects that data to spawn groundbreaking discoveries.

In addition, Gaia has assembled the largest database of chemical compositions of asteroids in the solar system. The consortium processing Gaia’s measurements is developing increasingly better algorithms that enable scientists to learn more about the stars Gaia sees. The mission will continue scanning the sky until 2025, when it will run out of fuel. Two more big data releases are expected to follow the one on June 13, and they will bring new surprises, including thousands of newly discovered exoplanets, De Bruijne said.

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Todd

I’d like to give a shout-out to my two favourite sources on all things space (besides @sean_robinson) Anton Petrov and PBS Space Time.

Anton Petrov does daily videos on science news. He’s very friendly and makes for great comfort viewing. I don’t understand how he can keep up with all his reading and making videos every single day, but he gets it done.

PBS Space Time is diving in to explaining the nature and quirks of space time. They’ve been doing it for years, and I’d recommend just watching some of their old explainers. Great production value here, good graphs and a good presenter. Amazing voice.

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Discovery of second repeating fast radio burst raises new questions

Fast radio bursts (FRBs) are intense, brief flashes of radio-frequency emissions, lasting on the order of milliseconds.

The Five-hundred-meter Aperture Spherical radio Telescope (FAST, below) and the Jansky Very Large Array (JVLA, middle) under the night sky.

An international team of astronomers have discovered a second persistently active fast radio burst, posing questions about the nature of the mysterious phenomena.

Fast radio bursts (FRBs) are intense, brief flashes of radio-frequency emissions, lasting on the order of milliseconds. The phenomenon was discovered in 2007, by graduate student David Narkevic and his supervisor Duncan Lorimer. The source of these highly energetic events is a mystery, but clues as to their nature are being gradually collected.

The new source, Fast radio burst 20190520B, was detected with the Five hundred-meter Aperture Spherical radio Telescope (FAST) in Guizhou, China, on May 20, 2019 and found in data in November that year, a new study (opens in new tab)reports.

Follow-up observations by the Jansky Very Large Array (VLA) program led by Caltech found weaker, constant radio emissions associated with the FRB, also allowing the Subaru telescope in Hawaii to localize the source to be within the fringes of a dwarf galaxy nearly 3 billion light-years from Earth.

Notably it is the second discovered repeating FRB to be associated with a persistent radio source (PRS), following the localization of FRB 121102 in 2012.

“The big surprise for me was realizing that the new FRB seems to be such a perfect ‘twin’ to an earlier discovery,” Casey Law, an astronomer at Caltech and a co-author who led the VLA program, told Space.com.

“Perhaps some would have preferred to say that the first such association [between an FRB and radio source] was a coincidence, because it was hard to explain. Now the second example shows that this is a real and critical part of the life of an FRB.”

The discovery raises new questions about the nature of FRBs, such as if the sources of the FRBs evolve over time, or alternatively whether different kinds of sources are capable of emitting FRBs.

“One of the key questions in the field of FRBs is whether all FRB sources repeat,” Di Li, of the National Astronomical Observatories of China (NAOC) and lead of the Commensal Radio Astronomy FAST Survey (CRAFTS) which detected FRB 190520B, told Space.com via email. “I personally favor an evolutionary picture in that all sources repeat, but the activity level drops precipitously as the source ages. Since FRB 20190520B is only the second of around 500 known FRBs to have a so-called PRS counterpart and both are extremely active, they could, in this hypothetical evolutionary picture, represent FRBs’ youth, which lasts not very long.”

Another special feature of FRB 190520B is its dispersion measurement, which indicates its emissions passed through the highest density of electrons of any FRB before being observed on Earth. This suggests the FRB is active in a local plasma environment, such as that created by a supernova, and is a newly created source.

While providing insights into the environment of FRB 190520B, the large disparity in dispersion measurements with other FRBs calls into question their use as “cosmic yardsticks” for measuring distances.

Franz Kirsten, a postdoctoral researcher at the Netherlands Institute for Radio Astronomy (ASTRON) and Chalmers University in Sweden who was not involved in the research, told Space.com that an evolutionary path for FRBs is possible, but with just these two sources, it’s hard to tell.

“We need to find more and to constrain this evolutionary stage model. We really need more at a different ages to say okay, this thing is fading away all the time,” Kirsten said. “So what would be really nice to see is if these persistent sources were indeed fading over time, over say, 10 to 20 year timescales. If we can say, okay, these are becoming fainter, then that is certainly an indication that this is a possibility.”

To follow up this research, co-author Yu Wenfei with the Shanghai Astronomical Observatory told Space.com that the “mechanisms responsible for the extra dispersion measure and the near-source environment of such repeating FRBs with a PRS association are the outstanding problems to follow and to solve.”

“I am optimistic that the FRB puzzle will be solved by investigating such extreme FRBs,” Yu said.

Di also sees high value in the discovery of more repeating FRB sources, along with trying to get a much better picture of the environments in which they occur, for example using the Hubble Space Telescope for follow-up observations.

Cooperation between astronomers and facilities across the globe will be crucial in finding, localizing and characterizing these mysterious phenomena, as it has been for the case of FRB 190520B.

“This discovery is impossible without international cooperation. FAST made the discovery and only VLA is capable of localizing it so efficiently. Each instrument has its forte and we all have one sky,” says Di.

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Todd

Physicists discover never-before seen particle sitting on a tabletop

This newly-discovered particle could account for dark matter.

A newly discovered particle could explain the mysterious dark matter.

Researchers have discovered a new particle that is a magnetic relative of the Higgs boson. Whereas the discovery of the Higgs boson required the tremendous particle-accelerating power of the Large Hadron Collider (LHC), this never-before-seen particle  —  dubbed the axial Higgs boson — was found using an experiment that would fit on a small kitchen countertop.

As well as being a first in its own right, this magnetic cousin of the Higgs boson  —  the particle responsible for granting other particles their mass  —  could be a candidate for dark matter, which accounts for 85% of the total mass of the universe but only reveals itself through gravity.

“When my student showed me the data I thought she must be wrong,” Kenneth Burch, a professor of physics at Boston College and lead researcher of the team that made the discovery, told Live Science. “It’s not every day you find a new particle sitting on your tabletop.”

The axial Higgs boson differs from the Higgs boson, which was first detected by the ATLAS and CMS detectors at the LHC a decade ago in 2012 ,  because it has a magnetic moment, a magnetic strength or orientation that creates a magnetic field. As such, it requires a more complex theory to describe it than its non-magnetic mass-granting cousin.

In the Standard Model of particle physics, particles emerge from different fields that permeate the universe, and some of these particles shape the universe’s fundamental forces. For example photons mediate electromagnetism, and hefty particles known as W and Z bosons mediate the weak nuclear force, which governs nuclear decay at subatomic levels. When the universe was young and hot, however, electromagnetism and weak force were one thing and all of these particles were nearly identical. As the universe cooled, the electroweak force split, causing the W and Z bosons to gain mass and to behave very differently from photons, a process physicists have called “symmetry breaking.” But how exactly did these weak-force-mediating particles get so heavy?

It turns out that these particles interacted with a separate field, known as the Higgs field. Perturbations in that field gave rise to the Higgs boson and lent the W and Z bosons their heft.

The Higgs boson is produced in nature whenever such a symmetry is broken, . “however, typically only one symmetry is broken at a time, and thus the Higgs is just described by its energy,” Burch said.

The theory behind the axial Higgs boson is more complicated.

“In the case of the axial Higgs boson, it appears multiple symmetries are broken together, leading to a new form of the theory and a Higgs mode [the specific oscillations of a quantum field like the Higgs field] that requires multiple parameters to describe it: specifically, energy and magnetic momentum,” Burch said.

Burch, who along with colleagues described the new magnetic Higgs cousin in a study(opens in new tab) published Wednesday (June 8) in the journal Nature, explained that the original Higgs boson doesn’t couple directly with light, meaning it has to be created by smashing other particles together with enormous magnets and high-powered lasers while also cooling samples to extremely cold temperatures. It’s the decay of those original particles into others that pop fleetingly into existence that reveals the presence of the Higgs.

The axial Higgs boson, on the other hand, arose when room-temperature quantum materials mimicked a specific set of oscillations, called the axial Higgs mode. Researchers then used the scattering of light to observe the particle.

“We found the axial Higgs boson using a tabletop optics experiment which sits on a table measuring about 3.2 by 3.2 feet (1 by 1 meters) by focusing on a material with a unique combination of properties,” Burch continued. “Specifically we used rare-earth Tritelluride (RTe3) [a quantum material with a highly 2D crystal structure]. The electrons in RTe3 self-organize into a wave where the density of the charge is periodically enhanced or reduced.”

The size of these charge density waves,   which emerge above room temperature, can be modulated over time, producing the axial Higgs mode.

In the new study, the team created the axial Higgs mode by sending laser light of one color into the RTe3 crystal. The light scattered and changed to a color of lower frequency in a process known as Raman scattering, and the energy lost during the color change created the axial Higgs mode. The team then rotated the crystal and found that the axial Higgs mode also controls the angular momentum of the electrons, or  the rate at which they move in a circle, in the material meaning this mode must also be magnetic.

“Originally we were simply investigating the light scattering properties of this material. When carefully examining the symmetry of the response  —  how it differed as we rotated the sample  —  we discovered anomalous changes that were the initial hints of something new,” Burch explained. “As such, it is the first such magnetic Higgs to be discovered and indicates the collective behavior of the electrons in RTe3 is unlike any state previously seen in nature.”

Particle physicists had previously predicted an axial Higgs mode and even used it to explain dark matter, but this is the first time it has been observed. This is also the first time scientists have observed a state with multiple broken symmetries.

Symmetry breaking occurs when a symmetric system that appears the same in all directions becomes asymmetric. Oregon University(opens in new tab) suggests thinking of this as being like a spinning coin that has two possible states. The coin eventually falls onto its head or tail face thus releasing energy and becoming asymmetrical.

The fact that this double symmetry-breaking still jives with current physics theories is exciting, because it could be a way of creating hitherto unseen particles that could account for dark matter.

“The basic idea is that to explain dark matter you need a theory consistent with existing particle experiments, but producing new particles that have not yet been seen,” Burch said.

Adding this extra symmetry-breaking via the axial Higgs mode is one way to accomplish that, he said. Despite being predicted by physicists, the observation of the axial Higgs boson came as a surprise to the team, and they spent a year attempting to verify their results, Burch said.

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Todd

Did China just detect signals from an alien civilization?

Probably not, experts say.

The internet is abuzz with rumors that China may have picked up signals from an alien civilization.

The news centers on observations by China’s “Sky Eye” — the Five-hundred-meter Aperture Spherical radio Telescope (FAST), which is located in southwestern Guizhou province.

One report, by the state-backed Science and Technology Daily, cited Zhang Tonjie, chief scientist of an extraterrestrial civilization search team co-founded by Beijing Normal University, the National Astronomical Observatory of the Chinese Academy of Sciences and the University of California, Berkeley.

Zhang is reported to have said that the team spotted two sets of intriguing signals in 2020 while sifting through FAST data gathered in 2019. Another signal was apparently picked up this year in data gathered on exoplanet targets.

However, Zhang reportedly also underscored the possibility that the signals are products of radio interference. Follow-up FAST observations are reportedly on tap. (The Science and Technology Daily story has since been removed from the outlet’s site.)

To get some perspective about the FAST rumors, Inside Outer Space reached out to Dan Werthimer, the Marilyn and Watson Alberts SETI (search for extraterrestrial intelligence) Chair in the Astronomy Department and Space Sciences Lab at the University of California, Berkeley. He works with the Beijing Normal University SETI researchers.

Werthimer threw cold water on the possibility that the FAST signals were produced by advanced aliens.

“These signals are from radio interference; they are due to radio pollution from Earthlings, not from ET. The technical term we use is ‘RFI’ — radio frequency interference. RFI can come from cell phones, TV transmitters, radar, satellites, as well as electronics and computers near the observatory that produce weak radio transmissions,” Werthimer said.

“All of the signals detected by SETI researchers so far are made by our own civilization, not another civilization,” Werthimer added. “It’s getting hard to do SETI observations from the surface of our planet. Radio pollution is getting worse, as more and more transmitters and satellites are built. Some radio bands have become impossible to use for SETI.”

Werthimer said that Earthlings might eventually have to go to the far side of the moon to do SETI work.

“A radio telescope on the backside of the moon would be shielded from all of our planet’s radio pollution,” he said.

China’s Five-hundred-meter Aperture Spherical radio Telescope, or FAST.

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Todd

Fastest-growing black hole ever seen is devouring the equivalent of 1 Earth per second

This behemoth has been powering an ultrabright quasar for 9 billion years.

The fastest-growing black hole ever seen is swallowing the mass equivalent of an entire Earth every second.

This gargantuan black hole has a mass 3 billion times that of the sun, and its rapid consumption is causing the behemoth to grow rapidly, an international research team found. The black hole gorges via a process called accretion, in which it siphons matter from a thin disk of gas and dust rotating around the massive object.

Other black holes of a similar size stopped growing billions of years ago, but this newly discovered black hole is still getting larger. It’s now 500 times bigger than Sagittarius A*,   the supermassive black hole at the heart of the Milky Way,  and would fit the whole solar system behind its event horizon, the boundary beyond which nothing can escape.

more in link…

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Fastest nova ever seen ‘rings’ like a bell thanks to feeding white dwarf

New findings have revealed strange details about a bright nova that appeared in June 2021.

Astronomers observing the fastest nova ever recorded have discovered that it reverberates periodically like a struck bell, with the unusual energetic phenomenon driven by a white dwarf feeding from a companion star.

The strange binary star system and the nova — designated V1674 Hercules and located in the constellation Hercules — could be the key to a better understanding of the chemistry of the solar system, the birth and death of stars and even the evolution of galaxies. V1674 Hercules first erupted on June 12, 2021, resulting in a burst of light so bright it was visible to the naked eye. Scientists identified the outburst as a nova, a sudden flare of bright light in a two-star system in which a white dwarf — a stellar remnant left over when a small or medium star runs out of nuclear fuel and sheds its outer layers — is dragging material away from a companion star.

more in link…

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Physicists link two time crystals in seemingly impossible experiment

New time crystal achievement could help bridge classical and quantum physics.

Physicists have created a system of two connected time crystals, which are strange quantum systems that are stuck in an endless loop to which the normal laws of thermodynamics do not apply. By connecting two time crystals together, the physicists hope to use the technology to eventually build a new kind of quantum computer.

more in link…

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Todd

2 Earthlike planets spotted in newly discovered nearby star system

The planets orbit a so-called M dwarf star, which is about 10 times smaller than the sun.

Two Earth-like exoplanets have been discovered orbiting the dwarf star HD 260655 only 33 light-years from Earth.

A planetary system with two Earthlike planets has been discovered only 33 light-years away from us.

This exciting solar system is one of the nearest to Earth and was spotted by NASA’s Transiting Exoplanet Survey Satellite (TESS) in October 2021. It took several months for scientists to confirm that the periodic dips in the brightness of the star HD 260655 were caused by orbiting planets crossing in front of its disk. The scientists were finally able to announce the discovery at a meeting of the American Astronomical Society in Pasadena, California, on Thursday (June 16).

The neighboring solar system contains “at least” two rocky planets the size of our Earth, but neither of these is likely to host life, the scientists said in a statement(opens in new tab). Calculations of the planets’ orbits revealed that both of those worlds circle their star at a distance that is too close to allow the existence of liquid water on their surfaces.

In fact, one of those two planets, called HD 260655b, about 1.2 times as big as Earth, takes only 2.8 days to orbit its star. The other, HD 260655c, which is 1.5 times Earth’s size, needs 5.7 days to complete one orbit.

The planets’ parent star is a so-called M dwarf, a tiny star about a tenth of the size and brightness of the sun. Still, temperatures on the planets’ surfaces reach a scorching 818 degrees Fahrenheit (437 degrees Celsius) and 548 degrees F (287 degrees C) respectively.

“We consider that range outside the habitable zone,” Michelle Kunimoto, a postdoctoral researcher in astronomy at the Massachusetts Institute of Technology (MIT) and one of the lead scientists behind the discovery said in the statement.

Still, these two exoplanets will provide an exciting new opportunity to learn more about Earth-like worlds outside our solar system.

“Both planets in this system are each considered among the best targets for atmospheric study because of the brightness of their star,” Kunimoto said. “Is there a volatile-rich atmosphere around these planets? And are there signs of water or carbon-based species? These planets are fantastic test beds for those explorations.”

The researchers continue studying the star system hoping it might contain even more planets, some of which, perhaps, could be a little farther away from the star.

“There might be more planets in the system,” Avi Shporer, MIT’s research scientist for the TESS mission and co-author of the discovery, said in the statement. “There are many multiplanet systems hosting five or six planets, especially around small stars like this one. Hopefully we will find more, and one might be in the habitable zone.”

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Todd

Sean Robinson wrote:

the fastest nova ever

Probably Rich Rider because he channels the Nova Force but I think at one time Sam Alexander was considered to be faster.

 

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Todd, Sean Robinson

[Sean Robinson]

Space calendar 2022

June 28: The new moon arrives at 10:52 p.m. EDT (0252 June 29 GMT).

July 13: The full moon of July, known as the Buck Moon, arrives at 2:38 p.m. EDT (1838 GMT). It will also be the biggest “Supermoon” of the year.

July 28: The new moon arrives at 1:54 p.m. EDT (1754 GMT).

Aug. 11: The full moon of August, known as the Sturgeon Moon, arrives at 9:36 p.m. EDT (0136 Aug. 12 GMT).

Aug. 11-12: The Perseid meteor shower peaks.

Aug. 27: The new moon arrives at 4:17 a.m. EDT (0817 GMT).

Sept. 10: The full moon of September, known as the Harvest Moon, arrives at 5:59 a.m. EDT (0959 GMT).

Sept. 23: Autumnal equinox. Today marks the first day of fall in the Northern Hemisphere and the first day of spring in the Southern Hemisphere.

Sept. 25: The new moon arrives at 5:54 p.m. EDT (2154 GMT).

• This reply was modified 2 years, 6 months ago by Sean Robinson.

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Todd

Fastest known star speeds around Milky Way’s black hole at 18 million mph

The star S4716 orbits the supermassive black hole at the heart of the Milky Way, coming as close to it as 92 million miles.

An illustration shows a star rapidly orbiting a supermassive black hole.

Astrophysicists have discovered the fastest known star which is racing around the black hole at the center of the Milky Way. The star, designated S4716, completes an orbit around the supermassive black hole Sagittarius A* (Sgr A*) in just around four years.

This means that the star is traveling at blisteringly fast speeds of around 18 million mph (29 million kph), or nearly 5,000 miles every second. During this rapid orbit of Sagittarius A*, which has an estimated diameter of 14.6 million miles (23.5 million kilometers), S4716 comes as close as 92 million miles (150 million km) to the supermassive black hole.

While this may seem incredibly distant, it is just 100 times the distance between Earth and the sun, which is a relatively small distance in cosmic terms. For example, the sun orbits Sgr A* at a distance of 26,000 light-years, with each light-year equivalent to 5.9 trillion miles (9.5 trillion km).

S4716 is part of a dense, tightly packed grouping of stars called the S cluster that orbits close to the galactic center and the Milky Way’s supermassive black hole. These S cluster stars all move particularly fast but vary in brightness and mass.

The discovery of a star so close to Sgr* could change our understanding of how our galaxy has evolved and especially regarding its fast-moving central stars.

“The short-period, compact orbit of S4716 is quite puzzling,” Masaryk University in Brno astrophysicist Michael Zajaček said in a statement(opens in new tab). “Stars cannot form so easily near the black hole. S4716 had to move inwards, for example by approaching other stars and objects in the S cluster, which caused its orbit to shrink significantly.”

The most famous star in the S-cluster is arguably S2, which has an orbital period around Sgr A* of 16 years and only ever comes as close to the supermassive black hole as 11 billion miles (18 million km). But while S2 has been incredibly useful for the study of Sgr A*, it isn’t always helpful.

The center of the Milky Way as seen by NIR2 shows the orbits of several S cluster stars around Sgr A* (marked with a black cross).

“S2 behaves like a large person sitting in front of you in a movie theater —  it blocks your view of what’s important. The view into the center of our galaxy is therefore often obscured by S2,” Florian Peissker, an astrophysicist at the University of Cologne and co-author on the new research, said in a statement. “However, in brief moments we can observe the surroundings of the central black hole.”

By continuously refining analytical techniques over two decades and combining them with 20 years of observations, Peissker and his team were finally able to confirm the rapid orbital period of S4716.

Five telescopes observed S4716: the Hawai’i-based Keck observatory instruments NIR2 and OSIRIS, and the Very Large Telescope instruments SINFONI, NACO and GRAVITY, providing detailed data on the star.

“For a star to be in a stable orbit so close and fast in the vicinity of a supermassive black hole was completely unexpected and marks the limit that can be observed with traditional telescopes,” Peissker added.

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Todd

‘Bouncing’ universe theory still can’t explain what came first

New research shows that a new model of a universe with endless periods of expansion and collapse still needs a beginning.

A bouncing model of the universe could do away with an initial singularity, but come with its own problems.

New research highlights a troubling problem with concepts of a cyclical universe that experiences infinitely alternating periods of rapid expansion and contraction, known as ‘bouncing universe’ models.

These bouncing universe models suggest the cosmos has no beginning, eliminating the need for a troubling singularity prior to the initial period of rapid inflation  — commonly known as the Big Bang —  needed by ‘beginning of time’ models.

University at Buffalo researchers say a newly suggested bouncing universe recipe that attempts to deal with the problem of entropy  —  the measure of unusable energy in the universe, which can only increase  —  suffers from a problem that has plagued previous models of endless inflation and contraction. It still needs a beginning.

“People proposed bouncing universes to make the universe infinite into the past, but what we show is that one of the newest types of these models doesn’t work,” University of Buffalo physicist Will Kinney said in a statement.(opens in new tab) “In this new type of model, which addresses problems with entropy, even if the universe has cycles, it still has to have a beginning.”

This means that proponents of cyclical models of the universe may have to go back to the drawing board.

The leading theory of the universe’s origins is so-called ‘cosmic inflation.’ This suggests that before time began all the energy in the cosmos was contained in a singularity  —  an infinite dimensionless point not described by the laws of physics.

This ended with a period of rapid inflation  —  the Big Bang  —  that saw the universe expand and cool, thus allowing the formation of matter  —  first atoms of hydrogen, then heavier elements, and eventually stars and galaxies.

The problem is, while this theory is very good at describing the universe as it ages from fractions of a second until the cosmic structure we see today, around 13.8 billion years later, it can’t describe the conditions of the singularity that existed before this inflation was kick-started. Or even what kick-started it.

An illustration of the expansion of the universe.

This issue is eliminated by a bouncing universe because if periods of inflation and collapse are infinite, then there was no beginning and thus no need to explain what preceded it. This would see the universe undergo similar inflation as suggested by the cosmic inflation model, but then ‘springing back’ on itself in a ‘Big Crunch’ of sorts.

Each new inflation period would, therefore, begin from the ‘wreckage’ of a previous period of expansion rather than a singularity. But, Kinney thinks that bouncing universes come with their own unique problems.

“Unfortunately, it’s been known for almost 100 years that these cyclic models don’t work because disorder, or entropy, builds up in the universe over time, so each cycle is different from the last one. It’s not truly cyclic,” the UB researcher said. “A recent cyclic model gets around this entropy build-up problem by proposing that the universe expands a whole bunch with each cycle, diluting the entropy.”

Kinney said that this new bouncing universe model tries to stretch everything out to get rid of cosmic structures such as black holes thus returning the universe to its original homogenous state before another bounce begins.

“We showed that in solving the entropy problem, you create a situation where the universe had to have a beginning. Our proof shows in general that any cyclic model which removes entropy by expansion must have a beginning,” he said, adding one bouncing universe may survive this assessment. “Our proof does not apply to a cyclic model proposed by Roger Penrose, in which the universe expands infinitely in each cycle. We’re working on that one.”

Kinney’s collaborator is UB physics Ph.D. student, Nina Stein. She highlighted the problem the duo had with a bouncing universe: “The idea that there was a point in time before which there was nothing, no time, bothers us, and we want to know what there was before that  —  scientists included.

“But as far as we can tell, in models that address entropy, there must have been a ‘beginning.’ There is a point for which there is no answer to the question, ‘What came before that?'”

This means, for now, the mystery of what existed before the universe and time itself remains and will be hotly debated by cosmologists for some time to come.

“There are a lot of reasons to be curious about the early universe, but I think my favorite is the natural human tendency to want to know what came before,” Stein said. “Across cultures and histories, humans have told stories about creation, about ‘in the beginning.’ We always want to know where we came from.”

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Todd

Sean Robinson wrote:

Why has humanity never been visited by aliens (that we know of)? The question has confounded scientists for decades, but two researchers have come up with a possible — and disturbing — explanation: Advanced civilizations could be doomed to either stagnate or die before they get the chance.

Er… I really hope these two researchers haven’t gambled their PhD hopes on this, because that theory has been around for decades before they “came up” with it.

 

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Sean Robinson

Scientists get gruesome look at how stars like our sun eat their own planets

When ordinary stars such as the sun use up hydrogen in their cores, they expand into red giants.

Scientists have known for years that one day, the sun will expand into a red giant and engulf its closest planets. A new study now explores how these devoured planets can influence the processes inside the dying star.

When stars the size of the sun run out of hydrogen in their cores, they balloon into red giants that may be more than ten times larger than the original star. As these red giants engulf the planets that orbit them, all sorts of things can happen.

Engulfing large planets, defined as 10 or more times the size of Jupiter, can trigger the star into shedding its envelope and increasing its brightness by several orders of magnitude for several thousands of years, the new study claims.

The study was conducted using a method called hydrodynamical simulations, and provides a glimpse into the possible future scenarios of our own solar system’s evolution. Because of the size of red giant stars, the researchers had to model only a small section of the boundary where the stars meet the planets to gain in-depth insights into the interactions.

“Evolved stars can be hundreds or even thousands of times larger than their planets, and this disparity of scales makes it difficult to perform simulations that accurately model the physical processes occurring at each scale,” Ricardo Yarza, a graduate astronomy student at the University of California, Santa Cruz, and lead author of the study, said in a statement(opens in new tab). “Instead, we simulate a small section of the star centered on the planet to understand the flow around the planet and measure the drag forces acting on it.”

The results may not only provide a glimpse into what will happen 5 billion years from now when our sun turns into a red giant, but also explain recent findings of planets orbiting white dwarfs, the burned-out stellar corpses into which stars turn after the red giant phase.

These studies, exploring the end stages of this planetary engulfment, suggest that some planets may survive being burnt by the red giants.

In our solar system, the closest planets to the sun, Mercury and Venus, are expected to get swallowed by the growing sun entirely. Earth, while it may survive, will be so scorched that it will become completely uninhabitable. Some of the more distant and currently freezing cold bodies, such as Jupiter, Saturn and their moons, may develop more life-friendly conditions in the vicinity of the blown-up sun.

While only a few planets that have likely survived a red giant engulfment have been observed so far, researchers believe that further studies of exoplanets will lead to more such discoveries.

“We believe [planetary engulfment] is relatively common,” Yarza said.

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Todd

James Webb Space Telescope snags its 1st direct photo of an alien world

“This is a transformative moment!”

The HIP 65426 b gas giant planet photographed by the James Webb Space Telescope on the background of the Digitized Sky Survey

The James Webb Space Telescope took its first direct image of a planet orbiting a distant star, proving its potential to revolutionize exoplanet research.

The absolute majority of exoplanets have only been observed through temporary dips in brightness of the stars they orbit; only about two dozen have been imaged directly. But that might soon change. Less than two months after it started its science operations, the James Webb Space Telescope has delivered its first direct photo of a planet beyond our solar system.

The planet, a gas giant orbiting the star called HIP 65426 some 385 light-years from Earth, appears in the image as a tiny splotch close to the glowing star. Webb photographed the exoplanet using its Near-Infrared Camera (NIRCam) and the Mid-Infrared Instrument (MIRI), each of which focuses on a different flavor of infrared light.

“This is a transformative moment, not only for Webb but also for astronomy generally,” Sasha Hinkley, an astronomer at the University of Exeter in the U.K. who led these observations, said in a statement(opens in new tab).

Scientists had discovered the planet in 2017 with the Very Large Telescope in Chile; Webb isn’t tailored to discovering new exoplanets and will instead excel at teaching scientists about worlds other observatories identified.

Exoplanets are extremely difficult to observe directly because they are so much fainter than the stars they orbit. This one, HIP 65426 b, could only be spotted thanks to a combination of factors. First, it’s extremely far away from its parent star, 100 times the distance from the sun to Earth (for comparison, Pluto orbits only 40 sun-Earth distances from the sun). Second, HIP 65426 b is also extremely massive — 12 times the size of Jupiter, the solar system’s largest planet.

Still, HIP 65426 b is about 10,000 times fainter than its host star in the near-infrared, and a few thousand times fainter in the mid-infrared part of the spectrum. Because of its sensitivity, however, Webb was capable of separating the two objects.

“Obtaining this image felt like digging for space treasure,” Aarynn Carter, an astronomer at the University of California, Santa Cruz, who led the analysis of the images, said in the statement. “At first all I could see was light from the star, but with careful image processing I was able to remove that light and uncover the planet.”

Both NIRCam and MIRI are equipped with devices called coronographs, which block the light of the central star.

“It was really impressive how well the Webb coronagraphs worked to suppress the light of the host star,” Hinkley said.

Observing the star through four different filters, the scientists eventually managed to obtain images that reveal the planet as a small blob of light. The blob’s shape varies in each image, a by-product of the telescope’s optics, the scientist said in the statement.

HIP 65426 b is a very young planet, only 15 to 20 million years old (compared to Earth’s 4.5 billion years); due to its gaseous nature it most certainly doesn’t host life. There are still many interesting questions astronomers might want to answer about this world and the many other planets that Webb will photograph in the future, including details of their chemical composition and age.

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Todd

James Webb Space Telescope captures stunning image of Neptune’s rings and moons

The image represents the first detailed look at the ice giant’s ring system for more than 30 years.

The James Webb Space Telescope (JWST) has captured its first image of the solar system ice giant Neptune, revealing the planet in a whole new light.

The image gives astronomers their best look at Neptune’s icy rings for 32 years, since the Voyager 2 spacecraft flew past the planet on its way out of the solar system. “It has been three decades since we last saw those faint, dusty bands, and this is the first time we’ve seen them in the infrared,” Heidi Hammel, a planetary scientist at Association of Universities for Research in Astronomy (AURA), said in a statement(opens in new tab).

Excitingly, in addition to the previously known bright, narrow Neptunian rings, the new James Webb Space Telescope image also shows some fainter dust rings around Neptune that even Voyager 2’s up-close-and-personal visit to the planet in 1989 couldn’t reveal — rings that scientists have never seen before.

Webb’s Near-Infrared Camera (NIRCam) image of Neptune, taken on July 12, 2022, brings the planet’s rings into full focus for the first time in more than three decades.

What appears to be missing from the JWST Neptune image is the characteristic blue color that has come to be associated with the ice giant from photos taken by the Hubble Space Telescope.

This blue color, which is caused by methane in the planet’s atmosphere, is absent because the JWST sees Neptune in near-infrared light. Because methane in the planet’s icy clouds absorbs light strongly at these wavelengths, the planet appears fairly dark to the JWST in regions not covered by bright, high-altitude clouds.

Another prominent feature seen in the JWST image is a series of bright patches in Neptune’s southern hemisphere. These represent high-altitude ice clouds in the ice giant’s atmosphere reflecting sunlight before the methane in the clouds absorb it. JWST’s image also highlights a continuous band of high-latitude clouds surrounding a previously-known vortex located at Neptune’s southern pole.

A thin and faint line of brightness can also be spotted circling the planet’s equator which may indicate the global circulation of Neptune’s atmosphere driving winds and storms across the ice giant.

The image also shows something intriguing at Neptune’s northern pole. At this point in Neptune’s 164-Earth-years-long orbit around the sun, its northern pole is just out of view from the JWST’s position almost 1 million miles (1.5 million kilometers) from Earth. Yet, the most powerful space telescope ever created has still managed to spot an intriguing brightness in the region of Neptune’s north pole.

The JWST images also provide scientists with a look at seven of Neptune’s moons. In particular, just above the ice giant in the zoomed-out version of its view of Neptune is a bright point of light that represents the moon Triton. This Neptunian moon is coated by a frozen layer of condensed nitrogen and appears so bright, outshining the methane-darkened Neptune, because it reflects around 70% of the sunlight that falls on it.

In this version of Webb’s Near-Infrared Camera (NIRCam) image of Neptune, the planet’s visible moons are labeled. Neptune has 14 known satellites, and seven of them are visible in this image.

At a distance from the sun that is 30 times that distance between Earth and our star, Neptune may seem distant. But, this is a cosmic stone’s throw in comparison to the galaxies and stars billions of light-years away that the JWST has been tailored to observe.

The Neptune image further demonstrates that even though the JWST was created to view extremely distant cosmic objects, looking back in time to the universe as it existed billions of years ago, it is still delivering important and ground-breaking results from inside the solar system.

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Space Calendar 2022

Oct. 8: The Draconid meteor shower, which is active Oct. 6-10, will peak overnight.

Oct. 9: The full moon of October, known as the Hunter’s Moon, arrives at 4:55 p.m. EDT (2055 GMT).

Oct. 20-21: The annual Orionid meteor shower, which is active all month long, peaks overnight.

Oct. 25: The new moon arrives at 6:48 a.m. EDT (1048 GMT).

Oct. 25: A partial solar eclipse will be visible from Europe, northern Africa, the Middle East and western parts of Asia.

Nov. 4-5: The annual South Taurid meteor shower peaks overnight.

Nov. 7-8: A total lunar eclipse will be visible from Asia, Australia, North America, parts of northern and eastern Europe and South America.

Nov. 8: The full moon of November, known as the Beaver Moon, arrives at 6:02 a.m. EST (1102 GMT).

Nov. 11-12: The annual North Taurid meteor shower peaks overnight.

Nov. 17-18: One of the most anticipated meteor showers of the year, the Leonid meteor shower peaks overnight.

Nov. 23: The new moon arrives at 5:57 p.m. EST (2257 GMT).

Dec. 7: The full moon of December, known as the Cold Moon, arrives at 11:08 p.m. EST (0408 Dec. 8 GMT).

Dec. 13-14: The annual Geminid meteor shower, one of the best meteor showers of the year, peaks overnight.

Dec. 21: Solstice. Today marks the first day of winter in the Northern Hemisphere and the first day of summer in the Southern Hemisphere.

Dec. 21-22: The annual Ursid meteor shower peaks overnight.

Dec. 23: The new moon arrives at 5:16 a.m. EDT (0916 GMT).

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Super-Earths are more common and more habitable than Earth. Astronomers are finding more of the billions out there.

Astronomers now routinely discover planets orbiting stars outside of the solar system — they’re called exoplanets.

Astronomers think the most likely place to find life in the galaxy is on super-Earths, like Kepler-69c, seen in this artist’s rendering.

Astronomers now routinely discover planets orbiting stars outside of the solar system — they’re called exoplanets. But in summer 2022, teams working on NASA’s Transiting Exoplanet Survey Satellite found a few particularly interesting planets orbiting in the habitable zones of their parent stars.

One planet is 30% larger than Earth(opens in new tab) and orbits its star in less than three days. The other is 70% larger than the Earth(opens in new tab) and might host a deep ocean. These two exoplanets are super-Earths — more massive than the Earth but smaller than ice giants like Uranus and Neptune.

I’m a professor of astronomy(opens in new tab) who studies galactic cores, distant galaxies, astrobiology(opens in new tab) and exoplanets. I closely follow the search for planets that might host life.

Earth is still the only place in the universe scientists know to be home to life. It would seem logical to focus the search for life on Earth clones — planets with properties close to Earth’s. But research has shown that the best chance astronomers have of finding life on another planet is likely to be on a super-Earth similar to the ones found recently.

A super-Earth is any rocky planet that is bigger than Earth and smaller than Neptune.

Common and easy to find

Most super-Earths orbit cool dwarf stars, which are lower in mass and live much longer than the sun. There are hundreds of cool dwarf stars for every star like the Sun, and scientists have found super-Earths orbiting 40% of cool dwarfs(opens in new tab) they have looked at. Using that number, astronomers estimate that there are tens of billions(opens in new tab) of super-Earths in habitable zones where liquid water can exist in the Milky Way alone. Since all life on Earth uses water, water is thought to be critical for habitability.

Based on current projections, about a third of all exoplanets(opens in new tab) are super-Earths, making them the most common type of exoplanet in the Milky Way. The nearest is only 6 light-years away(opens in new tab) from Earth. You might even say that our solar system is unusual since it does not have a planet with a mass between that of Earth and Neptune.

Most exoplanets are discovered by looking for how they dim the light coming from their parent stars, so bigger planets are easier to find.

Another reason super-Earths are ideal targets in the search for life is that they’re much easier to detect and study(opens in new tab) than Earth-sized planets. There are two methods astronomers use to detect exoplanets. One looks for the gravitational effect of a planet on its parent star and the other looks for brief dimming of a star’s light as the planet passes in front of it. Both of these detection methods are easier with a bigger planet.

Super-Earths are super habitable

Over 300 years ago, German philosopher Gottfried Wilhelm Leibniz argued that Earth was the “best of all possible worlds(opens in new tab).” Leibniz’s argument was meant to address the question of why evil exists, but modern astrobiologists have explored a similar question by asking what makes a planet hospitable to life. It turns out that Earth is not the best of all possible worlds.

Due to Earth’s tectonic activity and changes in the brightness of the sun, the climate has veered over time from ocean-boiling hot to planetwide, deep-freeze cold. Earth has been uninhabitable for humans and other larger creatures for most of its 4.5-billion-year history. Simulations suggest the long-term habitability of Earth was not inevitable(opens in new tab), but was a matter of chance. Humans are literally lucky to be alive.

Researchers have come up with a list of the attributes(opens in new tab) that make a planet very conducive to life. Larger planets are more likely to be geologically active, a feature that scientists think would promote biological evolution(opens in new tab). So the most habitable planet would have roughly twice the mass of the Earth and be between 20% and 30% larger by volume. It would also have oceans that are shallow enough for light to stimulate life all the way to the seafloor and an average temperature of 77 degrees Fahrenheit (25 degrees Celsius). It would have an atmosphere thicker than the Earth’s that would act as an insulating blanket. Finally, such a planet would orbit a star older than the Sun to give life longer to develop, and it would have a strong magnetic field that protects against cosmic radiation(opens in new tab). Scientists think that these attributes combined will make a planet super habitable.

By definition, super-Earths have many of the attributes of a super habitable planet. To date, astronomers have discovered two dozen super-Earth exoplanets(opens in new tab) that are, if not the best of all possible worlds, theoretically more habitable than Earth.

Recently, there’s been an exciting addition to the inventory of habitable planets. Astronomers have started discovering exoplanets(opens in new tab) that have been ejected from their star systems(opens in new tab), and there could be billions of them(opens in new tab) roaming the Milky Way. If a super-Earth is ejected from its star system and has a dense atmosphere and watery surface, it could sustain life for tens of billions of years(opens in new tab), far longer than life on Earth could persist before the sun dies.

One of the newly discovered super-Earths, TOI-1452b, might be covered in a deep ocean and could be conducive to life.

Detecting life on super-Earths

To detect life on distant exoplanets, astronomers will look for biosignatures, byproducts of biology(opens in new tab) that are detectable in a planet’s atmosphere.

NASA’s James Webb Space Telescope was designed before astronomers had discovered exoplanets, so the telescope is not optimized for exoplanet research. But it is able to do some of this science and is scheduled to target two potentially habitable super-Earths in its first year of operations. Another set of super-Earths with massive oceans discovered in the past few years, as well as the planets discovered this summer, are also compelling target(opens in new tab)s for James Webb.

But the best chances for finding signs of life in exoplanet atmospheres will come with the next generation of giant, ground-based telescopes: the 39-meter Extremely Large Telescope(opens in new tab), the Thirty Meter Telescope(opens in new tab) and the 25.4-meter Giant Magellan Telescope(opens in new tab). These telescopes are all under construction and set to start collecting data by the end of the decade.

Astronomers know that the ingredients for life are out there, but habitable does not mean inhabited. Until researchers find evidence of life elsewhere, it’s possible that life on Earth was a unique accident. While there are many reasons why a habitable world would not have signs of life, if, over the coming years, astronomers look at these super habitable super-Earths and find nothing, humanity may be forced to conclude that the universe is a lonely place.

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‘Pale blue dot’ planets like Earth may make up only 1% of potentially habitable worlds

We may need to look for “pale yellow dots” instead.

An artist’s impression of three kinds of habitable planets: a planet with mostly land; a planet with a good mix of land and sea, like Earth; and an ocean planet with barely any land.

Earth-like worlds with similar land-to-ocean ratios to our planet’s may be exceedingly rare.

According to a new study, Earth-like planets with about 30% of their surface covered by exposed continental land may make up only 1% of rocky worlds in stars’ habitable zones, the areas around stars where liquid water can exist on a planet’s surface. Instead, roughly 80% of potentially habitable worlds are completely dominated by land, and about 20% are purely ocean worlds, the study found.

The researchers came to this conclusion by modeling the relationship between water in a planet’s mantle and a planet’s recycling of continental land via plate tectonics.

“We Earthlings enjoy the balance between land areas and oceans on our home planet,” Tilman Spohn, executive director of the International Space Science Institute in Switzerland and a member of the research team, said in a statement(opens in new tab). “It is tempting to assume that a second Earth would be just like ours, but our modeling results suggest that this is not likely to be the case.”

The results indicate that Earth’s ratio of land to sea (1:3) is finely balanced and that for most planets, this ratio can easily tip over into mostly land or mostly sea. Spohn and his collaborator, Dennis Höning, a postdoctoral researcher at the Potsdam Institute for Climate Impact Research in Germany, concluded that the most likely time for this tipping point to occur is when a planet’s interior has cooled close to the temperature of Earth’s mantle, which is 2,570 degrees Fahrenheit (1,410 degrees Celsius) near the crust and as hot as 6,700 F (3,700 C) at greater depths. How well subduction zones at the boundaries between tectonic plates can cycle water over land at this mantle temperature dictates whether a planet will be dominated by land or ocean.

Earth reached these conditions about 2.5 billion years ago, at the end of the Archean, and our planet found the delicate balance we live in today. However, over billions of years, even Earth’s fine balance is unstable, although we don’t notice it because the rates of change are small, Spohn said. Other planets could have reached this tipping point much sooner.

“In the engine of Earth’s plate tectonics, internal heat drives geologic activity, such as earthquakes, volcanoes and mountain building, and results in the growth of continents,” Spohn said. On the other hand, “The land’s erosion is part of a series of cycles that exchange water between the atmosphere and the interior. Our numerical models of how these cycles interact show that present-day Earth may be an exceptional planet.”

Earth as a “pale blue dot” seen by Voyager 1 in 1990.

Spohn and Höning also considered other factors, such as how the outgassing of carbon dioxide (a greenhouse gas) contributes to the carbon-silicate cycle that acts as a planet’s long-term thermostat controlling the climate over millions of years. They found that, while both land- and ocean-dominated planets could still be habitable, with similar temperatures if all else were equal, their life-forms and climates might not be quite unlike Earth’s.

“Their fauna and flora may be quite different,” Spohn said.

The models indicated that ocean-dominated planets with less than 10% land would likely be warm, with moist atmospheres and tropical climates, whereas land-dominated worlds with less than 30% of their surfaces covered in ocean would be colder, drier and harsher than their ocean-dominated counterparts. On these land-dominated planets, cold deserts would stretch across the landmasses, and vast glaciers and ice sheets would be common.

Spohn and Höning’s results differ slightly from those of other research teams, however. For example, a study by Evelyn MacDonald of the University of Toronto found that for tidally locked worlds, the more land there is, the greater the average surface temperatures in general, Space.com previously reported. And perhaps the most famous study of land planets, led by Yutaka Abe of the University of Tokyo in 2011, found that land planets can remain habitable across much wider distances from their star than water worlds can and that they don’t freeze over as fast because there is less water for ice and snow. However, Abe’s study, along with others, agrees with Spohn and Höning’s conclusion that land-dominated planets would be far more common than Earth-like or water-rich planets.

Consequently, instead of looking for Carl Sagan’s quintessential “pale blue dot,” astronomers should be searching habitable zones for “pale yellow dots.”

The results were presented at the European Science Congress, which took place in Granada, Spain, from Sept. 18 to 23, and the findings are described in the team’s conference abstract.

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Iconic James Webb Space Telescope images get X-ray vision boost

The Chandra X-ray Observatory reveals new features in iconic images.

Four of the first science-quality images from NASA’s newest observatory have received a boost from X-ray vision.

The James Webb Space Telescope (JWST) images revealed this summer instantly became iconic, but a new team-up with NASA’s Chandra X-ray Observatory shows that despite being the most powerful space telescope yet built, JWST isn’t going to examine the universe in isolation. In fact, it may be at its most effective when paired with other instruments.

JWST is designed to see the cosmos in infrared, so its work is particularly enhanced when combined with instruments that observe space in different wavelengths of light, such as Chandra with its X-ray vision. The first images to be given an upgrade with Chandra X-ray data reveal new features that weren’t visible to JWST alone, according to a NASA statement.

Stephan’s Quintet of galaxies as seen by the James Webb Space Telescope and the Chandra X-ray Observatory.

Consider the image of Stephan’s Quintet, in which four galaxies are locked in a complex gravitational dance while a fifth galaxy is a distant observer of this cosmic choreography.

The JWST image of these galaxies showed features that astronomers had never seen before, particularly results of their interactions like tails of gas and bursts of intense star formation. When combined with data from Chandra and NASA’s retired Spitzer Space Telescope, the observations of Stephan’s Quintet revealed a hitherto unseen shock wave heating gas to tens of millions of degrees on any scale. This shock wave is created by one of the galaxies weaving through the others at around 2 million mph (3 million kph).

The Cartwheel Galaxy as seen by the James Webb Space Telescope and the Chandra X-ray Observatory.

Cosmic collisions are also key to another object JWST imaged, the distant Cartwheel galaxy. This galaxy got its unique shape when it collided with a smaller galaxy 100 million years ago. As the smaller galaxy ripped through the heart of the Cartwheel galaxy, it also kick-started a bout of intense star formation. Chandra data reveals X-rays in the Cartwheel galaxy emitted from superheated gas and individual exploded stars, as well as from neutron stars and black holes that are greedily feeding on material ripped from companion stars.

The galaxy cluster SMACS J0723 as seen by the James Webb Space Telescope and the Chandra X-ray Observatory.

Perhaps the most sparkling of JWST’s first images was of a galaxy cluster called SMACS J0723, which is located 4.2 billion light-years away from Earth. Chandra’s addition to these observations reveals gas heated to tens of millions of degrees on any scale.

Clusters like SMACS J0723 are host to thousands of galaxies and also vast reservoirs of superheated gas. Scientists estimate that the gas revealed by the JWST and Chandra partnership possesses a total mass of around 100 trillion times that of the sun. That’s several times more than the mass of every star in every galaxy in the cluster.

(That said, there’s still more to be seen. Dark matter accounts for more mass in this cluster than gas does, but this mysterious component doesn’t interact with light so is not visible even to the combined power of the JWST and Chandra.)

The Cosmic Cliffs of the Carina Nebula as seen by the James Webb Space Telescope and the Chandra X-ray Observatory.

The quartet of new images is rounded out with the Cosmic Cliffs of the Carina Nebula at the edge of the star-forming region of NGC 3324, arguably the most stunning image in the first set of images from JWST.

The Chandra image of these cliffs, which are located around 7,600 light-years from Earth, reveals more than a dozen X-ray sources, the majority of which are stars located in the outer region of a star cluster in the Carina Nebula. These stars are between 1 million and 2 million years old, making them very young in cosmic terms. Young stars like this are brighter in X-ray emissions than their older counterparts. Chandra’s data is particularly helpful here to identify young stars in the Carina Nebula and distinguish them from older Milky Way stars that might be lurking in JWST’s line of sight.

Also on display in the top half of the Chandra-enhanced image of the Carina Nebula is a diffuse X-ray emission that likely comes from hot gas from the most massive and hottest stars in the region, which are just outside the image’s field of view.

Over its operating lifetime, which was planned to last five years but may stretch to more like 20, JWST will be collaborating with other space-based instruments like Chandra, as well as with telescopes based here on Earth. The new images show how important these collaborations will be to astronomy in the years to come.

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Solar Orbiter speeds toward the sun

Wednesday, October 12, 2022: The Europe-led Solar Orbiter spacecraft captured this video sequence with one of its high-res cameras as it sped toward the star at the center of our solar system ahead of its close approach, the perihelion, on Oct.12.

The sequence shows the sun’s surface sparkling with activity in its gaseous atmosphere as it evolved between Sept. 20 and Oct. 10. Solar Orbiter makes regular close passes at the sun at about one third of the sun-Earth distance (within the orbit of the planet Mercury). Only NASA’s Parker Solar Probe has ever dared closer to the star, but that spacecraft doesn’t carry a sun-facing camera, as its optics wouldn’t survive in the hellish environment the probe encounters.

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Astronomers just spotted the most powerful flash of light ever seen

Gamma-ray bursts are the most energetic flashes of light known to exist in the universe.

The gamma-ray burst was also the nearest ever detected.

Astronomers just detected what may be the most powerful flash of light ever seen.

The so-called gamma-ray burst, the most energetic type of electromagnetic explosion known to exist in the universe, was first spotted by telescopes Sunday (Oct. 9).

Gamma-ray bursts, which were discovered accidentally by U.S. military satellites in the 1960s, are likely produced when giant stars explode at the ends of their lives before collapsing into black holes, or when ultradense stellar remnants known as neutron stars collide. Within seconds, these explosions unleash as much energy as the sun will emit during its entire 10-billion-year lifetime.

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One of the most extreme black hole collisions in the universe just proved Einstein right

An illustration of two black holes merging.

Researchers studying the aftermath of a gargantuan black hole collision may have confirmed a gravitational phenomenon predicted by Albert Einstein a century ago.

According to new research published today(opens in new tab) (Oct. 12) in the journal Nature, the phenomenon — which is known as precession and is similar to the wobbling motion sometimes seen in a spinning top — occurred when two ancient black holes crashed together and merged into one. As the two massive objects swirled closer together, they released enormous ripples through the fabric of space-time known as gravitational waves, which surged outward across the cosmos, carrying energy and angular momentum away from the merging black holes.

Scientists first detected these waves emanating from the black holes in 2020, using the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the U.S. and Virgo gravitational wave sensors in Italy. Now, after years of studying the wave patterns, researchers have confirmed that one of the black holes was rotating madly, to a degree never seen before.

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Mysterious dust ring around Uranus spotted in rediscovered Voyager 2 data

Uranus sports a faint ring system.

Scientists have uncovered a new mystery about Uranus’ rings buried deep in data from NASA’s iconic Voyager 2 mission.

Voyager 2 flew past Uranus in January 1986, discovering 10 moons and two rings while becoming the first and so far only spacecraft to visit the ice giant. One of those rings, which scientists call the zeta ring, has frustrated astronomers ever since — they weren’t even able to spot it again for nearly two decades. But last year, researchers got an unexpected gift: a new image of the Uranus’ ring system, including the elusive zeta ring, courtesy of amateur image processor Ian Regan.

“For a long time we thought we only had two images of this ring from Voyager 2,” Matthew Hedman, a planetary scientist at the University of Idaho, said during a presentation at the annual meeting of the American Astronomical Society’s Division of Planetary Sciences on Oct. 5. “This shows there’s a lot of information still encoded in the Voyager data that deserves a second look.”

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Record breaker! Newfound black hole is closest known to Earth – Space.com

Gaia BH1 is just 1,560 light-years from our planet.

Artist’s illustration of Gaia BH1, a black hole in a binary system that lies just 1,560 light-years from Earth. The system also harbors a sun-like companion star.

The black hole record books have just been rewritten.

A black hole about 10 times more massive than our sun lurks just 1,560 light-years from Earth, a new study reports. That’s about twice as close as the previous proximity champ.

The newfound object, a stellar-mass black hole called Gaia BH1, resides in a binary system whose other member is a sunlike star. That star is about as far from its companion black hole as Earth is from the sun, which makes Gaia BH1 very special indeed.

“While there have been many claimed detections of systems like this, almost all these discoveries have subsequently been refuted,” study lead author Kareem El-Badry, of the Harvard-Smithsonian Center for Astrophysics in Massachusetts and the Max Planck Institute for Astronomy in Germany, said in a statement(opens in new tab). “This is the first unambiguous detection of a sunlike star in a wide orbit around a stellar-mass black hole in our galaxy.”

Astronomers think that our Milky Way galaxy harbors about 100 million stellar-mass black holes, light-gobbling objects that are five to 100 times more massive than the sun.

Their small size makes these bodies relatively hard to detect, however, especially by telescope. (Gravitational-wave detectors have had more success recently, finding evidence of mergers involving these objects.) And the ones that scientists do see tend to be “X-ray binaries,” black holes that pull material from a companion star into an accretion disk around themselves. This fast-orbiting dust and gas emits X-rays, high-energy light that some powerful telescopes can observe.

Not all stellar-mass black holes that inhabit binary systems are actively feeding, however. Finding these dormant objects is even more difficult and requires different strategies.

The researchers employed one such alternate technique in the new study. They pored over data gathered by the European Space Agency’s (ESA) Gaia spacecraft, which is precisely mapping the positions, speeds and trajectories of about 2 billion Milky Way stars.

One of those stars is the companion to Gaia BH1. Its motion displays tiny irregularities — an indication that something massive and unseen is tugging on it gravitationally.

The Gaia measurements suggested that a black hole could be that tugger, but the scientists needed more data to know for sure. So they studied the star with a number of ground-based instruments, including the Gemini North and Keck 1 telescopes in Hawaii and the Magellan Clay and MPG/ESO telescopes in Chile.

These follow-up observations, combined with the Gaia data, allowed the team to take the system’s measure in detail. The unseen object contains the mass of 10 suns, they determined, and orbits the system’s center of mass about once every 186 Earth days. And it must be a black hole.

“Our Gemini follow-up observations confirmed beyond reasonable doubt that the binary contains a normal star and at least one dormant black hole,” El-Badry said. “We could find no plausible astrophysical scenario that can explain the observed orbit of the system that doesn’t involve at least one black hole.”

If the unseen object in Gaia BH1 were a star, for example, it would be far brighter than its companion, and therefore easier to see. But none of the team’s observations revealed a hint of a second star in the system.

The Gaia BH1 system is intriguing, and not just because it’s relatively close to us. (Close in the cosmic scheme of things, anyway; the Milky Way’s famous spiral disc is about 100,000 light-years wide.) The study team isn’t sure how the star and black hole came to be in their current positions.

Gaia BH1’s mass indicates that the star that died and gave rise to it must have been huge — at least 20 solar masses or so. Such giants live for just a few million years, and they puff up tremendously before they give up the ghost.

Modeling work suggests that such puffing would likely have destroyed the companion before it had a chance to evolve into a sunlike star (if the two were born at the same time). Or, if it survived, it should have ended up on a much tighter orbit than the one it currently occupies, the researchers said.

“It is interesting that this system is not easily accommodated by standard binary evolution models,” El-Badry said. “It poses many questions about how this binary system was formed, as well as how many of these dormant black holes there are out there.”

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Dead and alive at the same time: Black holes have quantum properties

Black holes behave like quantum particles a new study has revealed.

Black holes have properties characteristic of quantum particles, a new study reveals, suggesting that the puzzling cosmic objects can be at the same time small and big, heavy and light, or dead and alive, just like the legendary Schrödinger’s cat.

The new study, based on computer modeling, aimed to find the elusive connection between the mind-boggling time-warping physics of supermassive objects such as black holes and the principles guiding the behavior of the tiniest subatomic particles.

The study team developed a mathematical framework that placed a simulated quantum particle just outside a giant simulated black hole. The simulation revealed that the black hole showed signs of quantum superposition, the ability to exist in multiple states at once — in this case, to be at the same time both massive and not massive at all.

“We wanted to see whether [black holes] could have wildly different masses at the same time, and it turns out they do,” study lead author Joshua Foo, a PhD researcher in theoretical physics at the University of Queensland, said in a statement(opens in new tab). “Until now, we haven’t deeply investigated whether black holes display some of the weird and wonderful behaviors of quantum physics.”

The best known example of quantum superposition is the legendary Schrödinger’s cat, a thought experiment designed by early 20th century physicist Erwin Schrödinger to demonstrate some of the key issues with quantum physics. According to quantum theories, subatomic particles exist in multiple states simultaneously until they interact with the external world. This interaction, which could be the simple act of being measured or observed, throws the particle into one of the possible states.

Schrödinger, who won the Nobel Prize in Physics in 1933, intended the experiment to demonstrate the absurdity of quantum theory, as it would suggest that a cat locked in a box can be at the same time dead and alive based on the random behavior of atoms, until an observer breaks the superposition.

However, as it turned out, while a cat in a box could be dead regardless of the observer’s actions, a quantum particle may indeed exist in a double state. And the new study indicates that a black hole does as well.

American and Israeli theoretical physicist Jacob Bekenstein was the first to postulate that black holes may have quantum properties. Since a black hole is defined by its mass, its quantum superposition must mean that this odd gravitational gateway can have multiple masses that fall within certain ratios.

“Our modeling showed that these superposed masses were, in fact, in certain determined bands or ratios — as predicted by Bekenstein,” study co-author Magdalena Zych, a physicist at the University of Queensland and a co-supervisor of the research, said in the statement. “We didn’t assume any such pattern going in, so the fact we found this evidence was quite surprising.”

Not that we are any closer to understanding what is going on inside black holes. But whatever that is, it is probably even more fantastic than we could imagine.

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Milky Way stars photobomb picturesque spiral galaxy in stunning Hubble photo

This galaxy is located 300 million light-years away, but the star to the right is much closer to Earth.

Spiral galaxy NGC 5495 in the constellation Hydra.

The Hubble Space Telescope captured the sight of a beautiful spiral galaxy, adorned with the sparkle of two nearby stars.

Galaxy NGC 5495 lies 300 million light-years from Earth, far behind the jewel-like celestial bodies to the top-left of the galaxy’s center, and another to the right. These are stars within the Milky Way, Earth’s home galaxy that, like NGC 5495, is a spiral galaxy.

According to the European Space Agency (ESA) — which wrote a description of the “stately sweeping spiral arms” of the galaxy in a new NGC 5495 image(opens in new tab) published on Sept. 26 — 60% of galaxies are spiral galaxies(opens in new tab). This means that most of the stars in the universe are contained within a galaxy like our own, or like the one seen in the new Hubble image.

ESA officials write that NGC 5495 is a Seyfert galaxy(opens in new tab). These are galaxies with activity at their core. The most extreme version of an active galactic nucleus(opens in new tab) (AGN), called a quasar, is the brightest object in the known universe. This sort of glowing galactic heart is powered by the might of a supermassive black hole, which astronomers believe lie at the center of most if not all galaxies in the cosmos.

When these gravity pits accrete a lot of material around its outside, the material heats up and begins to glow. Galaxy NGC 5495 isn’t in the quasar category, but it’s still considered a churning AGN.

Galaxy NGC 5495 is also lovely to behold because it’s conveniently oriented face-on, allowing its core and spiral arms to be clearly visible. Although it’s not too visible from this perspective, spiral galaxy NGC 5495 is probably enveloped in a halo that lies just above and below the galactic disk. For reference, a halo is the hazy glow that sandwiches the band of the Milky Way that appears in the night sky.

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Black hole announces itself to astronomers by violently ripping apart a star

The black hole is located in a dwarf galaxy a million light-years away and ripped apart an unlucky star in a brutal tidal disruption event.

Artwork depicting a tidal disruption event (TDE). TDEs are causes when a star passes close to a supermassive black hole and get torn apart by the gravity of the latter. The debris forms a fan-shaped pattern around the black hole before eventually falling in.

A hitherto undiscovered black hole announced its presence to astronomers when it ripped apart and devoured a star that wandered too close to it.

The intermediate-mass black hole located in a dwarf galaxy a million light-years from Earth shredded the star in an occurrence that astronomers call a Tidal Disruption Event (TDE). The TDE made itself visible when it blasted out a flare of radiation so powerful that it briefly outshone every star in its dwarf galaxy home combined.

This TDE could help scientists better understand the relationship between galaxies and the black holes within them. It also provides astronomers with another intermediate black hole to study. “This discovery has created widespread excitement because we can use tidal disruption events not only to find more intermediate-mass black holes in quiet dwarf galaxies but also to measure their masses,” research co-author and UC Santa Cruz (UCSC) astronomer Ryan Foley said in a statement(opens in new tab).

The TDE flare  —  designated AT 2020neh  (opens in new tab)— was first observed by astronomers using the Young Supernova Experiment (YSE), an astronomical survey that detects short-lived cosmic events like supernova explosions, as the black hole first began to devour the star.

The observation of this initial moment of destruction was vital in allowing an international team led by UCSC scientists and research first author and Niels Bohr Institute astronomer Charlotte Angus to measure the mass of the black hole finding it to be around between around 100,000 and 1 million times the mass of the sun.(opens in new tab)

TDEs have been successfully used to measure the mass of supermassive black holes in the past, but this is the first time they have been shown to work in documenting the masses of smaller midsized intermediate-mass black holes.

That means that the initial sighting of the incredibly fast AT 2020neh flare could provide a baseline for measuring midsized black hole masses in the future.

“The fact that we were able to capture this midsize black hole whilst it devoured a star offered us a remarkable opportunity to detect what otherwise would have been hidden from us,” Angus said. “What is more, we can use the properties of the flare itself to better understand this elusive group of middle-weight black holes, which could account for the majority of black holes in the centers of galaxies.”

Astronomers discovered a star being ripped apart by a black hole in the galaxy SDSS J152120.07+140410.5, 850 million light years away. Researchers pointed NASA’s Hubble Space Telescope to examine the aftermath, called AT 2020neh, which is shown in the center of the image. Hubble’s ultraviolet camera saw a ring of stars being formed around the nucleus of the galaxy where AT 2020neh is located.

This midsized class of black holes have a mass range of between 100 and 100,000 times that of the sun, making them significantly more massive than stellar-mass black holes but much smaller than the supermassive black holes that sit at the heart of most galaxies, including the Milky Way.

Physicists have long suspected that supermassive black holes, which can have masses as great as millions or even billions of times that of the sun, could grow to these tremendous masses grow as the result of the merger of intermediate-mass black holes.

One theory regarding the mechanism that could facilitate this growth suggests the early universe was rich with dwarf galaxies possessing intermediate black holes.

As these dwarf galaxies merged or were swallowed by larger galaxies the intermediate black holes within them cannibalized each other, thus growing in mass. This chain process of increasingly larger mergers would eventually lead to the supermassive black hole titans that sit at the heart of most galaxies today.

“If we can understand the population of intermediate-mass black holes out there  — how many there are and where they are located  —  we can help determine if our theories of supermassive black hole formation are correct,” co-author and UCSC professor of astronomy and astrophysics, Enrico Ramirez-Ruiz said.

One question that remains regarding this theory of black hole growth is do all dwarf galaxies have their own intermediate-mass black hole. This is difficult to answer because as black holes trap light behind an outer boundary called the event horizon, they are effectively invisible unless they are feeding on surrounding gas and dust, or if they are ripping up stars in TDEs.

Astronomers can use other methods such as looking at the gravitational influence of stars that orbit them to infer the presence of black holes. These detection methods are currently not sensitive enough to be applied to distant black holes in the centers of dwarf galaxies, however.

As a result, few intermediate-mass black holes have been tracked down to dwarf galaxies. That means by detecting and measuring mid-sized black holes TDE flares like AT 2020neh could be a vital tool in settling the debate surrounding supermassive black hole growth.

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Car-sized asteroid will pass extremely close to Earth tonight

Don’t worry, we’re safe.

A small space rock is about to make a super close pass at Earth tonight, but don’t worry  —  we are perfectly safe.

The space rock, named BU 2023, was first spotted hurtling toward Earth on Saturday (Jan. 21) by famed Crimea-based astronomer and astrophotographer Gennadiy Borisov, the same man who in 2018 found the first interstellar comet, which now bears his name, Borisov.

The asteroid BU 2023 is only 11.5 to 28 feet (3.5 to 8.5 meters) wide, which means it would pose no risk to our planet, even if the trajectories of the two bodies were to intersect. However, observations of BU 2023 by other astronomers that followed Borisov’s discovery confirmed that the asteroid will miss our planet by a small but safe margin of 2,240 miles (3,600 kilometers). The rock will make its closest approach above the southern tip of South America today (Jan. 26) at 7:27 p.m. EST (0027 GMT on Jan. 27), according to NASA.(opens in new tab) You can watch a free live webcast of the asteroid’s flyby on Space.com, courtesy of astrophysicist Gianluca Masi of the Virtual Telescope Project in Italy, at 5:45 p.m. EST (2245 GMT).

The encounter with Earth will alter the trajectory of asteroid 2023 BU.

During its closest approach, BU 2023 will be about ten times closer to the planet than the orbit of geostationary weather satellites and nearly six times closer than the orbit of navigation satellites such as the U.S. GPS constellation. This distance makes the rock’s pass the fourth closest of any asteroid ever recorded, apart from those that actually hit Earth.

With its small size, BU 2023 poses no risk to the planet at all. If it were to enter Earth’s atmosphere, it would mostly burn up, producing a stunning fireball. A few small fragments could potentially survive and fall to the ground in the form of meteorites.

The combination of the rock’s small size and the close proximity at which it will pass the much larger Earth means that 2023 BU’s trajectory will change quite a bit as the rock receives a gravitational kick from the planet, NASA said in the statement.

Calculations based on the latest observations reveal that prior to its visit to Earth, the space rock’s orbit around the sun has been “roughly circular” and took 359 days to complete. Earth’s gravity will push BU 2023 into a more elliptical orbit, which will take the rock halfway to Mars at its farthest point from the sun. This alteration will add 66 days to BU 2023’s orbital period.

The eyes of hundreds of professional and amateur astronomers are expected to follow the encounter tonight and you can witness the close approach, too. For example, Italian astronomer Gianluca Masi will share his observations online onward from 3:45 p.m. EST (1915 GMT) today on his Virtual Telescope Project channel.(opens in new tab)

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[Sean Robinson]

Space Calendar 2023

2023 is a busy year for spaceflight and exploration enthusiasts with countless launches, mission milestones and skywatching events to look forward to.

With so much going on, it’s hard to keep track of everything. Never fear — keep up with the latest events in our 2023 space calendar. You can also Find out what’s up in the night sky this month with our visible planets guide and skywatching forecast.

Feb. 2: Comet C/2022 E3 (ZTF) will pass within 26 million miles (42 million km) of Earth. If visible, it will climb progressively higher during the early evening hours in the north-northeast sky, passing within 10 degrees of Polaris, the North Star, on Jan. 30 and within 1.5 degrees of the brilliant winter star Capella on Feb. 5.

Feb. 5: The full moon of February, known as the Snow Moon, arrives at 1:29 p.m. EST (1829 GMT)

Feb. 20: The new moon arrives at 2:06 a.m. EST (0706 GMT).

March 1: Jupiter meets Venus in conjunction. The pair will shine just a moon-width apart in the west-southwest sky, half an hour after sunset.

March 7: The full moon of March, known as the Worm Moon, arrives at 7:40 a.m. EST (1240 GMT).

March 21: The new moon will arrive at 1:23 p.m. EDT(1823 GMT).

Apr. 6: The full moon of April, known as the Pink Moon, will arrive at 12:34 a.m. EDT (0534 GMT).

Apr. 20: The new moon will arrive at 12:12 a.m. EDT (0512 GMT).

Apr. 20: A rare hybrid solar eclipse will occur today. The solar eclipse will be visible to observers across southeast Asia and Australia.

Apr. 22: The Lyrid meteor shower peaks tonight! The shower is active between Apr. 16 and Apr. 25 each year.

Related: Solar eclipses 2023: When, where & how to see them

• This reply was modified 1 year, 11 months ago by Sean Robinson.

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