Space

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[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
_______________________
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

Sean Robinson wrote:

debris superspreader event

you mean one of these?

Yea, they can be very dangerous.

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Todd, njerry, Sean Robinson

2 pieces of spaces junk zoom past each other in a near miss

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Todd

Guess that means I have to pay my bills next month. Still, it’s a fair trade-off

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Todd, Sean Robinson, Rocket

Because you were wondering…

What Would We Experience If Earth Spontaneously Turned Into A Black Hole?

One of the most remarkable facts about the Universe is this: in the absence of any other forces or interactions, if you start with any initial configuration of gravitationally bound masses at rest, they will inevitably collapse to form a black hole. A straightforward prediction of Einstein’s equations, it was Roger Penrose’s Nobel-winning work that not only demonstrated that black holes could realistically form in our Universe, but showed us how.

As it turns out, gravity doesn’t need to be the only force: just the dominant one. As the matter collapses, it crosses a critical threshold for the amount of mass within a certain volume, leading to the formation of an event horizon. Eventually, some time later, any object at rest — no matter how far away from the event horizon it initially was — will cross that horizon and encounter the central singularity.

If, somehow, the electromagnetic and quantum forces holding the Earth up against gravitational collapse were turned off, Earth would quickly become a black hole. Here’s what we would experience if that were to happen.

Right now, the reason Earth is stable against gravitational collapse is because the forces between the atoms that make it up — specifically, between the electrons in neighboring atoms — is large enough to resist the cumulative force of gravity provided by the entire mass of the Earth. This shouldn’t be entirely surprising, as if you considered the gravitational versus the electromagnetic force between two electrons, you’d find that the latter force was stronger by about a factor of a whopping ~1042.

In the cores of stars that are massive enough, however, neither the electromagnetic force nor even the Pauli exclusion principle can stand up to the force inciting gravitational collapse; if the core’s radiation pressure (from nuclear fusion) drops below a critical threshold, collapse to a black hole becomes inevitable.

Although it would take some sort of magical process, such as instantaneously replacing Earth’s matter with dark matter or somehow turning off the non-gravitational forces for the material composing Earth, we can imagine what would occur if we allowed this to happen.

First off, the material composing the solid Earth would immediately begin accelerating, as though it were in perfect free-fall, towards the center of the Earth. In the central region, mass would accumulate, with its density steadily rising over time. The volume of this material would shrink as it accelerated towards the center, while the mass would remain the same.

Over the timescale of mere minutes, the density in the center would begin to rise fantastically, as material from all different radii passed through the exact center-of-mass of the Earth, simultaneously, over and over again. After somewhere between an estimated 10 and 20 minutes, enough matter would have gathered in the central few millimeters to form an event horizon for the first time.

After just a few minutes more — 21 to 22 minutes total — the entire mass of the Earth would have collapsed into a black hole just 1.75 centimeters (0.69”) in diameter: the inevitable result of an Earth’s mass worth of material collapsing into a black hole.

If that’s what the Earth beneath our feet does, however, what would a human being on Earth’s surface experience as the planet collapsed into a black hole beneath our feet?

Believe it or not, the physical story that we’d experience in this scenario would be identical to what would happen if we instantly replaced the Earth with an Earth-mass black hole. The only exception is what we’d see: as we looked down, a black hole would simply distort the space beneath our feet while we fell down towards it, resulting in bent light due to gravitational lensing.

However, if the material composing the Earth still managed to emit or reflect the ambient light, it would remain opaque, and we’d be able to see what happened to the surface beneath our feet as we fell. Either way, the first thing that would happen would be a transition from being at rest — where the force from the atoms on Earth’s surface pushed back on us with an equal and opposite force to gravitational acceleration — to being in free-fall: at 9.8 m/s2 (32 feet/s2), towards the center of the Earth.

Unlike most free-fall scenarios we experience on Earth today, such as a skydiver experiences when jumping out of an airplane, you’d have an eerie, lasting experience.

– You wouldn’t feel the wind rushing past you, but rather the air would accelerate down towards the center of the Earth exactly at the same rate you did.
– There would be no drag forces on you, and you would never reach a maximum speed: a terminal velocity. You’d simply fall faster and faster as time progressed.
– That “rising stomach” sensation that you’d feel — like you get at the top of a drop on a roller coaster — would begin as soon as free-fall started, but would continue unabated.
– You’d experience total weightlessness, like an astronaut on the International Space Station, and would be unable to “feel” how fast you were falling.
– Which is a good thing, because not only would you fall faster and faster towards the Earth’s center as time went on, but your acceleration would actually increase as you got closer to that central singularity.

As you can see from the illustration above, the size of the arrows — as well as the speed that they move at — increases as we get closer to the central singularity of a black hole. In Newtonian gravity, which is a good approximation as long as you’re very far away from the event horizon (or the equivalent size of the event horizon), the gravitational acceleration you experience will quadruple every time your distance to a point halves. In Einsteinian gravity, which matters as you get close to the event horizon, your acceleration will increase even more significantly than that.

If you start off at rest with respect to the center of Earth, then by the time you’ve:

– fallen halfway to Earth’s center, a distance of ~3187 km, you’ll be falling at a speed of 11 km/s,
– fallen 90% of the way to Earth’s center, so you’re just ~637 km away, you fall at 34 km/s,
– fallen 99% of the way to Earth’s center, so you’re only ~64 km away, you’re moving at 112 km/s,
– made it to within 1 km of the very center, you’ll move at 895 km/s,
and while you might only be a millisecond from the event horizon, you’ll never get to experience what it’s like to get there.

That’s because your body, as you fall closer and closer to the center of the collapsing Earth, starts to experience enormous increases in tidal forces. While we normally associate tides with the Moon, the same physics is at play. Every point along any body in a gravitational field will experience a gravitational force whose direction and magnitude are determined by their displacement from the mass they’re attracted to.

For a sphere, like the Moon, the point closest to the mass will be attracted the most; the point farthest from it will be attracted the least; the points that are off-center will be preferentially attracted to the center. While the center itself experiences an average attraction, the points all around it will experience different levels, which stretches the object along the direction of attraction and compresses it along the perpendicular direction.

Here on the surface of Earth, these tidal forces on a human being are minuscule: a little less than a millinewton, or the gravitational force on a typical small earring. But as you get closer and closer to Earth’s center, these forces octuple each time you halve your distance.

…see next post…

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…continued…

By the time you’re 99% of the way to Earth’s center, the force pulling your feet away from your torso and your head away from your feet works out to about 110 pounds, as though the equivalent of nearly your own body weight was working to pull you apart.

When you experience a force on your body that’s equivalent to the gravitational acceleration on Earth — or a force that’s equal to your weight — scientifically that’s known as “1g” (pronounced “one-gee”). Typically, humans can only withstand a handful of gs over a sustained period of time before either lasting damage occurs or we lose consciousness.

Roller coasters might get up to 5 or 6 gs, but only for a brief period of time.
Fighter pilots can endure up to 12 to 14 gs, but only in a pressurized suit without losing consciousness.
Humans have experienced and survived extremely brief (less than a second) accelerations of between 40 and 70 gs, but the risk of death is very real.
Above that threshold, you’re headed for trauma and possibly death.

By the time you’ve reached about 25 kilometers from the central singularity, you’ll cross a critical threshold: one where these tidal forces will cause traumatic stretching your spine, causing it to lengthen so severely that the individual vertebrae can no longer remain intact. A little farther — about 14 kilometers away — and your joints will begin to come out of your sockets, similar to what happens, anatomically, if you were drawn-and-quartered.

In order to approach the actual event horizon itself, you’d have to somehow shield yourself from these tidal forces, which would rip your individual cells apart and even the individual atoms and molecules composing you before you crossed the event horizon. This stretching effect along one direction while compressing you along the other is known as spaghettification, and it’s how black holes would kill and tear apart any creature that ventured too close to an event horizon where space was too severely curved.

As spectacular as falling into a black hole would actually be, if Earth spontaneously became one, you’d never get to experience it for yourself. You’d get to live for about another 21 minutes in an incredibly odd state: free-falling, while the air around you free-fell at exactly the same rate. As time went on, you’d feel the atmosphere thicken and the air pressure increase as everything around the world accelerated towards the center, while objects that weren’t attached to the ground would appear approach you from all directions.

But as you approached the center and you sped up, you wouldn’t be able to feel your motion through space. Instead, what you’d begin to feel was an uncomfortable tidal force, as though the individual constituent components of your body were being stretched internally. These spaghettifying forces would distort your body into a noodle-like shape, causing you pain, loss of consciousness, death, and then your corpse would be atomized. In the end, like everything on Earth, we’d be absorbed into the black hole, simply adding to its mass ever so slightly. For the final 21 minutes of everyone’s life, under only the laws of gravity, our demises would all truly be equal.

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Todd

PBS Space Time has some great clips on the “space becomes time” theme.

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Sean Robinson, Todd

[Sean Robinson]

The Orionid meteor shower peaks tonight! Here’s how to see it.

It is recommended to view a dark sky for at least an hour to spot a shooting star.

An Orionid meteor seen by NASA’s All-Sky Fireball Network in 2015.

The Orionid meteor shower peaks tonight into tomorrow morning (Oct. 20-21), and the moon will be dim enough that skygazers might be able to see one or several of these shooting stars.

The bright streaks across the sky that people may see from now until early November are bits and pieces from Halley’s comet. Although the comet won’t be visible from Earth again until about four decades from now, it leaves behind a debris path in the solar system. And each year during mid-October, the Earth passes through this field. Our planet also passes through another part of this debris field in early May, resulting in the Eta Aquarid meteor shower.

The Orionid meteors are known for their speed because they travel at about 148,000 mph (66 km/s) into the Earth’s atmosphere, according to NASA. The meteor shower gets its name from its radiant, which is the point in the sky from which the streaks appear to emanate. The Orionid radiant is located near the constellation Orion, the hunter, next to the warrior’s lifted arm.

Skywatchers can start looking for Orion low in the eastern sky before dawn on any morning around the peak, Oct. 20-21. The setup is seen here from mid-northern latitudes. Even though the radiant, or point of origin of the meteors is in Orion, meteors can appear far from the constellation.

The longer streaks appear away from the radiant, so the best way to view meteors is to either find a place to lay down flat on the ground for at least an hour or to look towards the part of the sky that is slightly higher than the location of the constellation Orion.

Astrophotographer Jeff Berkes snapped this amazing photo of an Orionid meteor streaking above a lake in Elverson, Pennsylvania, on Oct. 22, 2011, during the peak of the annual Orionid meteor shower.

If possible, find a place that has little light pollution. Apps are great for locating constellations, but remember to avoid looking at a phone screen during meteor-shower viewing. It takes time for human eyes to adjust to the night sky, and a bright light could disrupt that eye training needed to spot dimmer meteors.

The moon will be a waxing crescent during the shower’s peak, according to NASA, so the little moonlight coming off of that lunar sliver won’t flood the sky during the meteor shower’s peak. This makes it easier for viewers to spot shooting stars. Spectators can expect to see about 10-20 meteors an hour, according to Bill Cooke, the lead for NASA’s Meteoroid Environment Office.

• This reply was modified 4 years, 2 months ago by Sean Robinson.

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Todd, Rocket, DavidM

Astronomers claimed galaxy was 98% dark matter. They were wrong.

The Dragonfly 44 galaxy looks like a smear across space. Physicists used to think it was hiding an enormous dark matter halo, but a new paper refutes that idea.

Back in 2016, researchers claimed to have found a galaxy made almost completely of dark matter and almost no stars. Now, on closer examination, that claim has fallen apart.

The galaxy, Dragonfly 44 (DF44), belongs to a class of mysterious objects known as ultra-diffuse galaxies or UDGs. Researchers have debated since the 1980s whether these vast, dim objects have a low mass, like dwarf galaxies smeared across huge reaches of space, or more like heavy, Milky Way-style galaxies that seem dim for two reasons: because they have almost no stars, and because a huge fraction of their mass is dark matter found in the outer fringes of the galaxy, in so-called dark matter haloes that emit no light. In a paper published in 2016 in The Astrophysical Journal Letters, scientists argued that DF44 was one of these galaxies with a big dark matter halo and few stars. They estimated its mass and found it was at least 98% dark matter.

But a new analysis, published Oct. 8 in the journal Monthly Notices of the Royal Astronomical Society, suggests the earlier study got it wrong. Researchers in the 2016 study assumed a bunch of mass was globbed into the dark matter halo; but actually, the new study showed a much lower total mass, indicating DF44 is one of those low-mass dwarf galaxies spread across space with normal percentages of dark matter.

DF44 is about 360 million light-years from Earth, so astronomers can’t directly measure its mass. Instead, they rely on proxies. Features like the speed at which objects circle a galaxy can indicate how massive it really is, as more gravity would cause objects to whirl faster.

In 2016, researchers claimed DF44 had a huge halo because of how fast its globular clusters (the few that call the galaxy home) seemed to be whirling around its center. (Globular clusters are blobby groups of stars that accumulate around galaxies.) But those velocity measurements turned out in 2019 to be incorrect

However, that wasn’t the end of the argument that DF44 had a huge amount of dark matter. That’s because the galaxy did seem to host a relatively high number of globular clusters.

Over time, researchers have noticed a general relationship between the number of globular clusters in a galaxy and that galaxy’s mass, said the new study’s lead author Teymoor Saifollahi, a doctoral candidate at the University of Groningen in the Netherlands.

And DF44 did seem to have a more globular clusters than you’d expect for a galaxy with so few stars. Early observations estimated about 100 of these clusters, which was later narrowed down to 80 in a 2017 paper in the Astrophysical Journal Letters. That would put the mass of DF44 squarely in Milky Way territory — a jarring result, with huge implications for how cosmologists understand the history of galaxy formation across space-time. Galaxies, in the new model, would be primarily dark matter objects, able to form without many stars or other luminous matter at all. All those bright dots in space would just be optional accessories.

Saifollahi and his colleagues did their own count, however, and they landed on a much lower number: 20. That would indicate that DF44 has a normal, dwarf galaxy mass — a much less exciting result.

It’s not surprising that the two research teams ended up with such different counts, he said.

Why such a stark difference in estimates?

“It is not as easy as just looking and counting,” Saifollahi told Live Science. “In the images, there are all sort of astronomical objects, and not all of them are globular clusters. Some are just stars in the middle of the way from us to the galaxy, and some are very far objects which look small.”

There’s always some level of uncertainty in figuring out what those objects are, he said. That’s especially true when you take into account that researchers assume globular clusters too small and dim to see from our vantage point always exist around any galaxy.

The key difference between the 2017 analysis and the 2020 analysis, Saifollahi said, has to do with where they assumed most globular clusters inDF44 were located. The 2017 team made a rough guess as to how far the clusters would orbit from the center of the galaxy, based on standard numbers associated with dwarf galaxies, and then looked for candidates in that area. For the 2020 paper, the researchers actually measured how far the clusters extended from the center of the galaxy, and found that the stellar globs clustered much closer to DF44’s center than expected. Counting possible clusters only in that smaller area produced a smaller number

“This is also an interesting finding on the side,” he said.

In future studies of UDGs, he said, scientists will have to be more careful not to rely on standard assumptions about globular clusters. He and his colleagues plan to more closely examine other UDGs that have high estimated numbers of globular clusters, and see if those estimates hold up.

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NASA
LIVE 9:30 p.m. EDT: NASA TV Coverage of the Landing (10:55 p.m.) of the Space Station Expedition 63 Crew
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OSIRIS-REx TAGs Surface of Asteroid Bennu
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NASA to Announce New Science Results About Moon
NASA will announce an exciting new discovery about the Moon from the Stratospheric Observatory for Infrared Astronomy (SOFIA) at a media teleconference at 12 p.m. EDT Monday, Oct. 26.

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Todd

Sean Robinson wrote:

NASA
LIVE 9:30 p.m. EDT: NASA TV Coverage of the Landing (10:55 p.m.) of the Space Station Expedition 63 Crew
______________________________________________________

OSIRIS-REx TAGs Surface of Asteroid Bennu
_________________________________________________________

NASA to Announce New Science Results About Moon
NASA will announce an exciting new discovery about the Moon from the Stratospheric Observatory for Infrared Astronomy (SOFIA) at a media teleconference at 12 p.m. EDT Monday, Oct. 26.

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Sean Robinson

[Sean Robinson]

Aliens watching us? Scientists spot 1,000 nearby stars where E.T. could detect life on Earth

The list could help guide the search for intelligent aliens.

Artist’s impression of an exoplanet transiting a red dwarf star.

As humanity ramps up its search for alien life, we should keep in mind that E.T. might be hunting for us as well.

A new study makes that point by identifying more than 1,000 nearby stars that are favorably positioned for spotting life on Earth.

“If observers were out there searching [from planets orbiting these stars], they would be able to see signs of a biosphere in the atmosphere of our Pale Blue Dot,” study lead author Lisa Kaltenegger, an associate professor of astronomy at Cornell and director of the university’s Carl Sagan Institute, said in a statement.

“And we can even see some of the brightest of these stars in our night sky without binoculars or telescopes,” Kaltenegger said.

Earthly transits?

Astronomers have found most of the more than 4,000 exoplanets discovered to date with the “transit method,” which detects the tiny brightness dips caused when an orbiting world crosses its host star’s face from the observer’s perspective. This strategy was used to great effect by NASA’s pioneering Kepler space telescope and is currently being employed by its successor, the Transiting Exoplanet Survey Satellite (TESS).

Soon, researchers will also be able to scan the atmospheres of some nearby transiting planets for potential signs of life. This search will be one of the many tasks undertaken by NASA’s $9.8 billion James Webb Space Telescope, which is scheduled to launch late next year, for example. And coming ground-based megascopes such as the Giant Magellan Telescope will do such work as well.

In the new study, Kaltenegger and co-author Joshua Pepper, an associate professor of physics at Lehigh University, thought about Earth as the target of a transiting-planet survey rather than the source of one.

The scientists scrutinized the datasets of TESS and Europe’s star-mapping Gaia spacecraft, looking for stars within 100 parsecs (about 326 light-years) that are aligned with the ecliptic, the plane of Earth’s orbit around the sun. (Such alignment is necessary to see Earth cross the sun’s face.)

This search turned up 1,004 qualifying main-sequence stars — stars that, like our sun, fuse hydrogen into helium in their cores. And 508 of those stars “guarantee a minimum 10-hour-long observation of Earth’s transit” across the sun’s face, Kaltenegger and Pepper wrote in the new study, which was published online Tuesday (Oct. 20) in the journal Monthly Notices of the Royal Astronomical Society: Letters.

A new tool for the E.T. search

The new results deal only with stars. Scientists don’t know how many planets orbit the 1,004 suns flagged by Kaltenegger and Pepper, let alone how many of these systems host worlds that may be conducive to life as we know it.

Those numbers should come into clearer focus as exoplanet hunters like TESS continue their work. And the new study can serve as a signpost for astrobiologists in the meantime and into the future, Kaltenegger said.

“If we’re looking for intelligent life in the universe that could find us and might want to get in touch, we’ve just created the star map of where we should look first,” she said.

• This reply was modified 4 years, 2 months ago by Sean Robinson.

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Todd

Sean Robinson wrote:

Such a debris superspreader event would not be unprecedented. In February 2009, for example, the operational Iridium 33 communications satellite collided with the defunct Russian military satellite Kosmos 2251. The smashup generated 1,800 pieces of trackable debris by the following October, as well as many others too small to detect.

Humanity has also twice spawned big debris clouds on purpose — during anti-satellite tests in 2007 and 2019 conducted by China and India, respectively.

Such events, and Thursday night’s potential collision, highlight the growing threat that orbital debris poses to spaceflight and exploration. The International Space Station has had to maneuver itself away from potential collisions three times in 2020 alone, for example. And as the costs of launch and satellite development both continue to fall, Earth orbit will get more and more crowded, often with craft operated by relative neophytes.

The spaceflight community therefore needs to come up with debris-minimizing guidelines, and soon, many experts say. Such guidelines could include a requirement that spent rocket bodies be deorbited shortly after launch, so they can’t be involved in close encounters like the one that will occur Thursday night over the South Atlantic.

Siri, what’s Kessler Syndrome?

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Sean Robinson

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Sean Robinson, Todd

Ferme la porte!

NASA asteroid probe is overflowing with space-rock samples

The OSIRIS-REx team will work to stow the sample as fast as possible to minimize mass loss.
NASA’s first-ever asteroid-sampling operation apparently went a little too well.

The agency’s OSIRIS-REx probe snagged so much dirt and rock from the surface of the near-Earth asteroid Bennu on Tuesday (Oct. 20) that the spacecraft’s sampling mechanism didn’t close properly, allowing some of the collected material to escape into space, mission team members announced Friday (Oct. 23).

OSIRIS-REx’s handlers now plan to stow the collected material in the probe’s return capsule as soon as possible, to minimize the material lost. The team hopes to begin that crucial, multi-day operation on Tuesday (Oct. 27), NASA officials said.

Captured by the spacecraft’s SamCam camera on Oct. 22, 2020, this series of three images shows that the sampler head on NASA’s OSIRIS-REx spacecraft is full of rocks and dust collected from the surface of the asteroid Bennu. They show also that some of these particles are slowly escaping the sampler head. Analysis by the OSIRIS-REx team suggests that bits of material are passing through small gaps where the head’s mylar flap is slightly wedged open.

“Bennu continues to surprise us with great science and also [by] throwing a few curveballs,” Thomas Zurbuchen, NASA’s associate administrator for science at the agency’s headquarters in Washington, said in a statement.

“And although we may have to move more quickly to stow the sample, it’s not a bad problem to have,” Zurbuchen said. “We are so excited to see what appears to be an abundant sample that will inspire science for decades beyond this historic moment.”

The $800 million OSIRIS-REx mission launched in September 2016 and arrived at Bennu in December 2018. The mission’s chief goal is to deliver at least 2.1 ounces (60 grams) of pristine Bennu material to Earth. That will happen on Sept. 24, 2023, when the return capsule touches down in the Utah desert.

All indications are that the probe collected more than enough material during Tuesday’s maneuver, which featured a six-second-long “kiss” of Bennu with OSIRIS-REx’s Touch-And-Go Sample Acquisition Mechanism (TAGSAM) head.

The head sank deep into Bennu, perhaps getting up to 19 inches (48 centimeters) beneath the surface, mission principal investigator Dante Lauretta, of the University of Arizona, said during a news conference Friday. And photos captured by the spacecraft show that the sampling head is jammed with material, suggesting that OSIRIS-REx snagged, at minimum, hundreds of grams of Bennu bits, Lauretta added.

But those photos also revealed a cloud of particles escaping from the TAGSAM head, through gaps where small rocks prevented the sampler’s mylar flap from closing all the way. The jailbreak was spurred when OSIRIS-REx moved TAGSAM around to get a look at the collected sample, Lauretta said.

He and his colleagues originally planned to weigh the sample Saturday (Oct. 24), an operation that would have involved spinning OSIRIS-REx around a bit. But that operation would doubtless have liberated more asteroid particles, so mission team members now plan to proceed directly to sample stowage. (They also canceled an engine burn that would have slowed OSIRIS-REx’s retreat from Bennu, for the same reason.)

Skipping the weighing step is no great loss, Lauretta said.

“The challenge that we have in front of us is due to the fact that the TAGSAM is probably really full of material,” he said during Friday’s new conference. The top priority at this point, he added, “is to get this sample safely stowed and minimize any more loss.”

It’s tough to quantify how much material has been lost, Lauretta said. But he estimated that up to 10 grams of Bennu samples flew the coop as a result of the recent photography activities, and that “grams to tens of grams” could be lost during the stow operation. (The escape rate seems to be quite low when Bennu stays relatively still, Lauretta said.) If these numbers are correct, and OSIRIS-REx did indeed snag hundreds of grams of material on Tuesday, then the mission is in fine shape going forward.

The samples cannot be stowed immediately, Lauretta said. The team first needs to finalize and validate an updated stowing plan that takes into account leaking asteroid particles, for example. The mission also must secure a long, continuous block of time on NASA’s Deep Space Network (DSN), the set of radio dishes around the globe the agency uses to communicate with its far-flung spacecraft. Sample stowage will be an involved and time-intensive process with lots of back-and-forth between OSIRIS-REx and the ground, Lauretta explained.

These complications notwithstanding, the mission team is happy and excited about how things have gone to date, Lauretta said.

“We couldn’t have performed a better sample-collection experiment,” he said. “The particles are escaping because we were almost a victim of our own success here.”

OSIRIS-REx has been backing away from Bennu since Tuesday’s sampling maneuver and will not swoop in toward the asteroid again, Lauretta said. Assuming the sample is stowed successfully next week, the next big milestone will come in early March, when OSIRIS-REx departs Bennu and starts heading back toward Earth.

That trip will be relatively uneventful, Lauretta said — until September 2023, when the return capsule comes down to Earth (containing an unknown amount of material; there’s no good way to measure the mass once the sample has been stowed).

The asteroid rocks and dirt will then make their way to labs around the world, where scientists can study them for clues about the solar system’s early days and the role that carbon-rich space rocks like Bennu may have played in helping life get started on Earth.

Though OSIRIS-REx (whose name is short for “Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) is NASA’s first asteroid-sampling mission, it’s not the first one overall. Japan’s Hayabusa probe returned small grains of the stony asteroid Itokawa in 2010, and its successor, Hayabusa2, is hauling a sample of the carbon-rich asteroid Ryugu Earthward now. The Ryugu material will land in Australia this coming December.

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Todd

Sean Robinson wrote:

Ferme la porte!

when i was little, my dad used to use the phrase “Ferme la Bouche” a lot. It is a lot more fancy than “shut up” but the strange thing was we are not at all French in any way.

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Sean Robinson

Rocket wrote:

but the strange thing was we are not at all French in any way

I dunno, sounds like you were a little bit French in one way if you couldn’t shut the fuck up.

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Rocket, Sean Robinson

Putain de merde

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Sean Robinson

The 175,000 People Searching for “Planet Nine” – Nerdist.com

In the hunt for Planet Nine, astronomers eye a new search technique for the elusive world – Space.com

Astronomers find new way to hunt the elusive Planet 9 – LiveScience.com

THE HUNT FOR PLANET 9 IS BACK ON – Inverse.com

FOR FIVE YEARS, ASTRONOMERS HAVE HUNTED FOR A DISTANT AND MYSTERIOUS NINTH PLANET that may be orbiting our Sun.

Dubbed Planet Nine, the ninth planet was predicted by scientists to exist based on mathematical calculations — but the hypothetical world has never been observed.

That may be about to change. A team of researchers have come up with a new method to search for distant objects lurking in the darkest corners of space. And they believe it could help us find our long lost Planet Nine.

The scientists presented the new method at the annual meeting of the American Astronomical Society’s Division for Planetary Sciences on Tuesday. It forms the basis of a paper accepted for publication by The Planetary Science Journal.

A NINTH PLANET? — Planet 9 was “discovered” in 2015 on the basis of mathematical evidence by scientists at the California Institute for Technology.

The evidence suggests that a Neptune-sized planet far beyond Pluto orbits our Sun in a highly elongated ellipsis. The planet, so the hypothesis goes, has a mass about 10 times that of Earth and and orbit about 20 times farther from the Sun as Neptune, the eighth and farthest known planet from the Sun.

Planet 9 may take between 10,000 and 20,000 Earth years to complete one orbit around the Sun, according to NASA.

“If Planet Nine is out there, it’s going to be incredibly dim,” Malena Rice, a Yale astronomer and one of the researchers on the new work, said in a statement.

While it only exists in theory, direct detection of a ninth planet would be the first discovery of a new planet orbiting the Sun in 200 years.

SHIFTING AND STACKING — Planet 9 is incredibly distant from the Sun, which means that it is also incredibly dark. The sunlight reflected from its surface would be so faint that — if it does exist — it is nearly impossible to detect with traditional methods.

In their presentation, astronomers Rice and colleague Gregory Laughlin suggest a new technique called ‘shifting and stacking’ that may shed light on Planet 9 — and all the other objects potentially lurking in our cosmic neighborhood. Shifting and staking works by gathering light from thousands of images captured by space telescopes to identify the faint orbital pathways of distant objects.

The technique first ‘shifts’ images taken by a telescope, sort of like moving a camera as you’re taking pictures, and then stacks images together in order to combine the faint light captured in them.

By doing so, the images can reveal the orbital pathway of a distant object moving in space.

“You really can’t see them without using this kind of method,” Rice said.

The researchers tested the method out on three trans-Neptunian objects, or dwarf planets, in the outer solar system. These already-discovered objects orbit the Sun at a further distance than the planet Neptune. Already, they have started the search through dark, unexplored regions of the outer solar system. So far, they have detected 17 potential objects.

That’s a lot of new neighbors.

“If even one of these candidate objects is real, it would help us to understand the dynamics of the outer solar system and the likely properties of Planet Nine,” Rice said.

“It would be beautiful if it’s out there.”

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NASA’s Mars rover Perseverance is halfway to the Red Planet

Perseverance will touch down on Feb. 18.

NASA’s Mars 2020 Perseverance rover reached its halfway point — 146.3 million miles (235.4 million kilometers) — on its journey to the Red Planet’s Jezero Crater on Oct. 27, 2020, at 4:40 EDT (2040 GMT).

NASA’s next Mars rover is halfway to its otherworldly destination.

The Mars 2020 rover Perseverance, which launched on July 30, has now traveled 146 million miles (235 million kilometers) in deep space — half of the total required to reach the Red Planet, mission team members announced Tuesday (Oct. 27).

“While I don’t think there will be cake, especially since most of us are working from home, it’s still a pretty neat milestone,” Julie Kangas, a mission navigator at NASA’s Jet Propulsion Laboratory (JPL) in Southern California, said in a statement Tuesday. “Next stop, Jezero Crater.”

The 28-mile-wide (45 km) Jezero, where Perseverance will touch down on Feb. 18, hosted a lake and a river delta in the ancient past. The car-size rover will characterize the area’s geology and climate in detail and search for possible signs of long-dead life, among other tasks.

Perseverance will also collect and cache several dozen samples from the Martian terrain for future return to Earth. The return campaign, a joint NASA-European Space Agency effort, could get this precious Mars material here as early as 2031.

In addition, Perseverance carries on its belly a small helicopter named Ingenuity, a demonstration craft designed to help pave the way for extensive rotorcraft exploration of Mars in the future.

The rover reached the exact halfway point in its interplanetary journey — 146.3 million miles (235.4 million km) — at 4:40 p.m. EDT (2040 GMT) Tuesday, NASA officials said. But Perseverance is taking a curving route to Mars, so the spacecraft is not midway between the two planets as the space-crow flies.

“In straight-line distance, Earth is 26.6 million miles [42.7 million km] behind Perseverance and Mars is 17.9 million miles [28.8 million km] in front,” Kangas said.

The Perseverance team hasn’t been sitting on its hands during the mission’s current “cruise phase.” Over the past two weeks, for example, team members have performed checkouts of four different rover instruments. Everything is working well, NASA officials said.

“If it is part of our spacecraft and electricity runs through it, we want to confirm it is still working properly following launch,” mission deputy chief engineer Keith Comeaux, also of JPL, said in the same statement.

“Between these checkouts — along with charging the rover’s and Mars Helicopter’s batteries, uploading files and sequences for surface operations, and planning for and executing trajectory correction maneuvers — our plate is full right up to landing,” Comeaux said.

You can track the rover’s deep-space trek in real time here.

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Will our solar system survive the death of our sun?

It’s gonna get ugly.

An artist’s depiction of the solar system as it appears today.

Our sun’s death is a long way off — about 4.5 billion years, give or take — but someday it’s going to happen, and what then for our solar system?

The trouble begins before the death proper: The first thing we have to contend with is the elderly sun itself. As the fusion of hydrogen continues inside the sun, the result of that reaction — helium — builds up in the core.

With all the waste product hanging around, it gets harder for the sun to do its fusion dance. But the inward crushing weight of the sun’s atmosphere doesn’t change, so to maintain balance the sun has to increase the temperature of its fusion reactions, leading ironically to a hotter core.

This means that as the sun ages, it gets steadily brighter. The dinosaurs knew a dimmer sun than we see today, and in as little as a few hundred million years, Earth will get too hot to handle.

Our atmosphere will get stripped away. Our oceans will evaporate. For awhile, we’ll look something like Venus, locked in a choking, carbon dioxide atmosphere.

And then it gets worse.

In the final stages of hydrogen fusion, our sun will swell and swell, becoming distorted and bloated — and red. The red giant sun will consume Mercury and Venus for sure. It might or might not spare Earth, depending on exactly how large it gets. If the sun’s distended atmosphere does reach our world, Earth will dissolve in less than a day.

But even if the sun’s expansion stops short, it won’t be pretty for Earth. The extreme energies emitted by the sun will be intense enough to vaporize rocks, leaving behind nothing more than the dense iron core of our planet.

Shuffling the deck

The outer planets won’t enjoy the increased radiation output from the sun, either. The rings of Saturn are made of almost pure water ice, and the future sun will simply be too hot for them to survive. The same goes for the ice-locked worlds orbiting those giants. Europa, Enceladus, and all the rest will lose their icy shells.

At first, the increased radiation will blast the four outer planets, stripping away their atmospheres, which are just as fragile as that of a terrestrial planet. But as the sun continues to swell, some of the outer tendrils of its atmosphere can find their way to the giants, traveling through funnels of gravity. Feeding on that material, the outer planets can gorge themselves, becoming far larger than they ever were before.

But the sun still won’t be done. In its final stages, it will repeatedly swell and contract, pulsing for millions of years. This isn’t the most stable situation, gravitationally speaking. The deranged sun will push and pull the outer planets in odd directions, potentially drawing them into a deadly embrace or kicking them entirely out of the system.

A new home

For a few hundred million years, the outermost parts of our solar system will be a decent place to call home. With so much heat and radiation pouring from the red giant sun, the habitable zone — the region around a star where the temperatures are just right for liquid water — will shift outward.

As we saw above, at first the moons of the outer worlds will melt, losing their icy shells and potentially hosting liquid water oceans on their surfaces. Eventually, the Kuiper belt objects, including Pluto and its mysterious friends, will also lose their ices. The largest may transform into mini-Earths orbiting a distant, distorted red sun.

But eventually, our sun will give up the struggle, shrugging off its outer atmosphere in a series of outbursts that leave behind the star’s core: a white-hot lump of carbon and oxygen.

This white dwarf will initially be staggeringly hot, blasting off X-ray radiation that can do brutal damage to life as we know it. But within a billion years or so, the white dwarf will settle down to more manageable temperatures and simply hang out for trillions upon trillions of years.

That dim white dwarf will host a new habitable zone, but because the former sun will be so cool, that zone would be incredibly close, much closer than Mercury orbits our sun today.

At that distance, any planet (or planetary core) would be vulnerable to tidal disruption — a pretty way of saying the gravity of the white dwarf could inadvertently rip a planet to shreds.

But that may be the best we’ll get.

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Todd

https://www.cnet.com/news/alien-civilizations-could-be-eyeing-earth-from-these-exoplanets/?ServiceType=facebook_page&TheTime=2020-10-24T17:51:08&UniqueID=7F0C6BA8-1621-11EB-9FB2-8515933C408C&ftag=COS-05-10aaa0a&PostType=image&fbclid=IwAR0EjclXbMf04PgnYUmydY05JcrjopGssoTs9sBoqp5P_Ay-ydR94rU3DiY

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[Sean Robinson]

Tiny rogue planet is the smallest free-floating exoplanet candidate yet

The newfound exoplanet candidate likely has a mass between that of Mars and Earth.

An artist’s impression of a gravitational microlensing event by a free-floating “rogue” planet.

Astronomers have spotted the smallest “rogue planet” candidate yet known, a world possibly smaller than Earth that apparently cruises through our Milky Way galaxy unattached to a star.

The potential exoplanet has a mass that’s somewhere between that of the Earth and Mars, which is just 10% as hefty as our world. If confirmed, the discovery would be a big milestone in the study of rogue planets, which are thought to be incredibly abundant throughout the galaxy and beyond but are very difficult to detect.

“Our discovery demonstrates that low-mass free-floating planets can be detected and characterized using ground-based telescopes,” Andrzej Udalski, co-author of a new study announcing the find and principal investigator of the Optical Gravitational Lensing Experiment (OGLE) project, said in a statement.

Common but hard to see

Astronomers have discovered more than 4,000 confirmed exoplanets to date. Most of them have been found using the “transit method,” which notes the brightness dips caused when a world crosses its host star’s face from an observer’s perspective, or the “radial velocity method,” which spots stellar movements induced by a planet’s gravitational pull.

Both of these techniques depend on the existence of a host star, so they cannot be used to hunt for rogue worlds. But another planet-hunting technique can do the job — “gravitational microlensing,” which involves watching foreground objects pass in front of distant background stars. When this happens, the closer body can act as a gravitational lens, bending and magnifying the star’s light in ways that can reveal the foreground object’s mass and other characteristics.

“Chances of observing microlensing [events] are extremely slim because three objects — [light] source, lens and observer — must be nearly perfectly aligned,” study lead author Przemek Mroz, a postdoctoral researcher at the California Institute of Technology in Pasadena, said in the same statement. “If we observed only one source star, we would have to wait almost a million years to see the source being microlensed.”

But planet hunters such as Mroz don’t observe the heavens one star at a time. In the new study, for example, Mroz and his colleagues analyzed data gathered by OGLE. This project, led by the University of Warsaw in Poland, uses a 1.3-meter telescope at Las Campanas Observatory in Chile to monitor millions of stars near the Milky Way’s center on every clear night.

The researchers pulled a very interesting signal out of the OGLE observations — an event called OGLE-2016-BLG-1928, which at 42 minutes long is the shortest microlensing event ever detected. The team further characterized the event using data collected by the Korea Microlensing Telescope Network, which operates telescopes in Chile, Australia and South Africa.

“When we first spotted this event, it was clear that it must have been caused by an extremely tiny object,” co-author Radoslaw Poleski, of the Astronomical Observatory of the University of Warsaw, said in the same statement.

The team’s calculations suggest that the lensing body has a mass between that of Mars and Earth, and is probably closer in heft to the Red Planet than to our own world. And the OGLE-2016-BLG-1928 candidate is likely zooming through deep space all by its lonesome.

“If the lens were orbiting a star, we would detect its presence in the light curve of the event,” Poleski said. “We can rule out the planet having a star within about 8 astronomical units.”

One astronomical unit, or AU, is the average distance from Earth to the sun — about 93 million miles (150 million kilometers). In our own solar system, an object at 8 AU would circle the sun between Jupiter and Saturn — a strange place for a small, rocky planet to exist.

The new study was published online today (Oct. 29) in Astrophysical Journal Letters. You can read a preprint of it for free at arXiv.org.

Booted from home

Astronomers have discovered only a handful of confirmed rogue planets to date. But this small number suggests a large population, scientists say, given how difficult these exotic worlds are to detect.

Astronomers think that most rogue planets were born in the “normal” way, coalescing from the gas and dust spinning around a newly formed star. But these worlds were eventually booted out of their native systems by gravitational interactions with other bodies, especially their gas-giant siblings.

Theory suggests that most rogues ejected in this way are rocky worlds with masses 30% to 100% that of Earth, Mroz and his colleagues note in the new study. So the OGLE-2016-BLG-1928 candidate may well be fairly representative of the teeming but elusive rogue population.

We could soon start getting a much better handle on that population. For instance, NASA’s Nancy Grace Roman Space Telescope, which is scheduled to launch in the mid-2020s, will conduct a large microlensing survey, among other science tasks. That survey will likely find about 250 rogue planets, including 60 or so that are Earth-mass or lighter, a recent study found.

• This reply was modified 4 years, 2 months ago by Sean Robinson.

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Gravitational-wave treasure trove reveals dozens of black hole crashes

A diagram shows mergers of black holes and neutron stars observed by the LIGO and Virgo gravitational-wave detectors.

Scientists can now catch gravitational waves better than ever before.

Although physicists only observed the first of these cosmic “chirps” in 2015, subsequent improvements in the detectors have opened up more and more of these signals to scientific study. The twin Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors in Louisiana and Washington, plus a European counterpart called Virgo, are currently on another observing hiatus for the coronavirus pandemic and ongoing upgrades, but scientists affiliated with the project have spent their time combing through data to create a new catalog of dozens of gravitational-wave signals detected during the first half of the third joint observing campaign, which ran from April to September 2019.

“One key to finding a new gravitational-wave signal about once every five days over six months were the upgrades and improvements of the two LIGO detectors and the Virgo detector,” Karsten Danzmann, director at the Max Planck Institute for Gravitational Physics in Germany, said in a statement.

In particular, he pointed to new hardware like lasers and mirrors, plus new techniques for reducing background noise. “This increased the volume in which our detectors could pick up the signal from, say, merging neutron stars by a factor of four!” Danzmann said.

The better sensitivity has allowed scientists to capture more gravitational waves, but also a more diverse array of signals, according to researchers affiliated with the project.

“When you look at the catalog, there’s one thing all events have in common: They come from mergers of compact objects such as black holes or neutron stars. But if you look more closely, they all are quite different,” Frank Ohme, a physicist at the Max Planck Institute for Gravitational Physics in Germany, said in the statement. “We’re getting a richer picture of the population of gravitational-wave sources. The masses of these objects span a very wide mass range from about that of our sun to more than 90 times that, some of them are closer to Earth, some of them are very far away.”

A handful of the 39 detections included in the new release have already hit headlines, including the first observed lopsided black-hole merger, the first observed merger to create an intermediate-mass black hole, and the first observed merger to include a mysterious object that falls in the size range between neutron stars and black holes.

But those aren’t the only intriguing detections in the batch, the researchers emphasized. One of the detections might represent a small black hole and a neutron star, a mixed merger that physicists have been waiting to see. “Unfortunately the signal is rather faint, so we cannot be entirely sure,” Serguei Ossokine, another physicist at the institute said in the release.

Another detection represents the lightest black holes scientists have observed merging to date, he added — one about six times the mass of the sun and the other half again as large.

And there’s still more data to be studied. The second half of the same observing run began in November 2019 and lasted until the coronavirus pandemic forced the detectors to send scientific staff home for safety in late March 2020.

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The Milky Way’s quiet, introverted monster won’t spin

Many black holes spin much faster than this.

An image from the Atacama Large Millimeter/submillimeter Array (ALMA) shows molecular gas clouds around the region where the Milky Way’s central, supermassive black hole is known to exist. That region, highlighted in red, looks dark and silent.

There’s a beast hiding at the center of the Milky Way, and it’s barely moving.

This supermassive black hole, Sagittarius A* (SgrA*), has a mass 4.15 million times that of our sun. It first revealed itself to scientists as a mysterious source of radio waves from the galaxy’s center back in 1931; but it wasn’t until 2002 that researchers confirmed the radio waves were coming from something massive and compact like a black hole —— a feat that earned them the 2020 Nobel Prize in physics. Just days before the team learned about their Nobel on Oct. 6, another group learned something new about the black hole: It’s spinning more slowly than a supermassive black hole should, moving less than (possibly far less than) 10% of the speed of light.

Black holes, despite their awesome power, are extraordinarily simple objects. All the distinguishing features of the matter that forms and feeds them gets lost in their infinitesimal singularities. So every black hole in the galaxy can be described with just three numbers: mass, spin and charge.

Once researchers locate a black hole in space, measuring the mass is pretty straightforward —— just check how strongly its mass is tugging on nearby objects. To get the mass of SgrA*, scientists just observed its influence on the “S-stars,” a collection of the Milky Way’s innermost stars that get accelerated to incredible speeds as they whip around the black hole in tight orbits. And researchers assume that, like most large objects in space, black holes don’t have strong electromagnetic charges.

(Planet Earth, for example, has some positively charged particles and some negatively charged particles, but they cancel each other out across the whole planet. The other planets and known stars work the same way. Researchers assume black holes are similarly neutral in charge.)

That leaves spin as the remaining measurable feature of SgrA*, and now researchers think they have evidence that the supermassive is an unusually slow spinner.

Spin matters for two main reasons.

First, as Live Science previously reported, a black hole’s event horizon —— the shadowy region within which not even light can escape the monster’s gravity —— grows as it gains more mass, reaching further and further from the singularity of the black hole. But as the black hole spins faster and faster, the event horizon shrinks. Very fast-spinning black holes should have smaller event horizons than slower-moving black holes of the same mass.

Second, spin is thought to play a role in the two white-hot jets of matter that sometimes launch into space at incredible speeds from a black hole’s axis of rotation. Most Milky Way-sized galaxies have supermassive black holes at their center, and often these galaxies have enormous jets visible bursting from their cores.

The Hubble Space Telescope captured an enormous relativistic jet, in blue, emerging from the supermassive black hole at the center of galaxy M87. (The giant spiral galaxy itself appears as a bright point in the image, with the black hole too small to see.) The black hole’s second jet extends in the other direction, and is hidden from view.

But the Milky Way has no visible jets. That on its own implies that SgrA* probably isn’t spinning very fast. Researchers think that a fast-spinning black hole stirs up the disk of accreting matter whirling just outside its event horizon, accelerating some of that matter to burst out as a jet. What scientists know about the quiet SgrA* already suggests it either has a small accretion disk, is barely spinning, or both.

In a new paper, a team of researchers attempted to measure SgrA*’s spin. Once again, they relied on the visible S-stars to learn what their big dark companion is doing.

Right now, the researchers found, the S-stars circle SgrA* on two orbital planes. If you were to draw their orbits around the black hole and view the system from the side, they’d form an X. SgrA* must be spinning at a rate less than 10% of the speed of light, they found, because any faster movement would have knocked the S-stars out of their X-shaped orbital planes by now.

That’s because those orbits, the researchers wrote, are likely as old as the S-stars themselves. The stars still follow the orbits they were born with. If SgrA* were spinning very fast, that wouldn’t be the case.

When heavy objects spin very fast in space, that spin influences anything in orbit around them. Over time, that massive object tugs on the orbits of those smaller objects, making them line up more and more with the rotating object’s own direction of spin. The slower the spin is, the weaker the effect, and the longer it takes for those objects to line up in orbit around their hefty chief.

The stars are old enough that the spin should have noticeably tugged on them if it were very strong. With their orbits as pristine as the day they were born, the S-stars strongly suggest an upper speed limit for SgrA* at just one-tenth the speed of light. And it may be spinning much slower.

This result also would explain why SgrA* doesn’t seem to have any visible jets, they wrote. A first close-up image of SgrA*’s shadow, expected to come in the near future from another research team, should help confirm this, they wrote.

The paper was published Oct. 1 in The Astrophysical Journal Letters.

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NASA Discovers a Rare Metal Asteroid That’s Worth $10,000,000,000,000,000,000 – Observer

Hubble Examines Massive Metal Asteroid Called ‘Psyche’ That’s Worth Way More Than Our Global Economy – Forbes

This isn’t your typical space rock: There’s a metal asteroid out there worth $10,000 quadrillion – USA Today

This isn’t your typical space rock.

The asteroid 16 Psyche, one of the most massive objects in the main asteroid belt orbiting between Mars and Jupiter, could be made entirely of metal, according to a study published this week.

Even more intriguing, the asteroid’s metal is worth an estimated $10,000 quadrillion (that’s 15 more zeroes), more than the entire economy of Earth.

“We’ve seen meteorites that are mostly metal, but Psyche could be unique in that it might be an asteroid that is totally made of iron and nickel,” study lead author Tracy Becker of the Southwest Research Institute said in a statement.

“Earth has a metal core, a mantle and crust. It’s possible that as a Psyche protoplanet was forming, it was struck by another object in our solar system and lost its mantle and crust,” Becker said.

Using the Hubble Space Telescope, Becker was able to analyze the asteroid in greater detail than ever before. The findings were published in a study in the Planetary Science Journal.

The study comes as NASA is preparing to launch a spacecraft (also dubbed Psyche), which will travel to the asteroid as part of an effort to understand the origin of planetary cores.

The mission is set to launch in 2022 and will arrive at the asteroid in 2026. Metal asteroids are relatively rare in the solar system, and scientists believe Psyche could offer a unique opportunity to see inside a planet.

According to NASA, what makes the asteroid Psyche unique is that it appears to be the exposed nickel-iron core of an early planet.

Becker said that “what makes Psyche and the other asteroids so interesting is that they’re considered to be the building blocks of the solar system. To understand what really makes up a planet and to potentially see the inside of a planet is fascinating.

“Once we get to Psyche, we’re really going to understand if that’s the case, even if it doesn’t turn out as we expect,” she said. “Any time there’s a surprise, it’s always exciting.”

NASA has no plans to bring the massive asteroid home and lacks the technology to mine it for its valuable metals. Researchers told CBS News in 2017 that they don’t plan to take advantage of the value of the asteroid’s composition.

“We’re going to learn about planetary formation, but we are not going to be trying to bring any of this material back and using it for industry,” Carol Polanskey, project scientist for the Psyche mission, told CBS at the time.

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Todd

Rare Halloween ‘Blue Moon’ is a spooky treat for us all

Skywatchers, ghouls and (especially) werewolves take note: The moon will be full this Halloween night across the entire United States.

This is a truly special confluence of spookiness; a Halloween full moon visible for most time zones on Earth hasn’t happened since 1944, according to the Farmers’ Almanac. It won’t happen again until 2039.

But wait, there’s more: The Oct. 31 full moon also happens to be a “blue moon,” a designation for the second full moon to occur in a single calendar month. Blue moons are relatively rare as well, occurring on average just once every 2.5 years or so. We last saw one in March 2018. The next one is in August 2023.

You can watch the Halloween Blue Moon live online in a webcast from the Virtual Telescope today starting at 12:30 p.m. EDT (1630 GMT). Astrophysicist Gianluca Masi will webcast live views of the full moon as it rises over Rome, Italy. You can follow the webcast on Virtual Telescope website here, and on YouTube. It will also be carried live on this page at start time.

The current definition of “blue moon” is actually a misinterpretation of the original one, by the way. The term once referred to the third full moon in a season (winter, spring, summer or fall) that sported four full moons instead of the usual three, a definition laid out by the Maine Farmers’ Almanac in the 1930s.

“But in 1946, amateur astronomer and frequent contributor to Sky & Telescope James Hugh Pruett (1886–1955) incorrectly interpreted the Almanac’s description, and the second-full-moon-in-one-month usage was born,” Sky & Telescope wrote in an explainer this week.

And in case you were wondering — “blue moon” has nothing to do with color. The moon can sometimes appear bluish, thanks to the scattering of light by dust or smoke particles in Earth’s atmosphere, but such effects are not tied to the moon’s phases at all.

We can also call this Halloween full moon the Hunter’s Moon, the traditional name for the first full moon after the Harvest Moon. The Harvest Moon is the one that falls closest to the Northern Hemisphere autumnal equinox, which occurred this year on Sept. 22. In 2020, that distinction went to the full moon of Oct. 1.

And one last thing: The Halloween full moon this year also qualifies as a “micro-moon” or “minimoon,” because it will occur when the moon is close to its farthest point from Earth in its elliptical orbit. For example, on Oct. 30, the moon will be 252,522 miles (406,394 kilometers) from us — notably farther than its average distance of about 238,900 miles (384,500 km). You probably won’t notice the difference, however, unless you’re particularly sharp-eyed or obsessive about these sorts of things.

Editor’s note: This story was updated on Oct. 31 to include webcast details of the Blue Moon from The Virtual Telescope. It was also corrected to reflect that the full moon will be visible to some in Australia and elsewhere on Nov. 1, not Halloween.

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Todd

Get ready for the ‘Great Conjunction’ of Jupiter and Saturn

In their closest encounter since 1623, Jupiter and Saturn appear as a single star in the evening sky next month.

During the “Great Conjunction” on Dec. 21, 2020, Jupiter and Saturn will be about one-tenth of a degree apart, their closest approach since 1623.

All through the summer and into the fall, the two gas giants of the solar system, Jupiter and Saturn, have been calling attention to themselves in the southern evening sky.

Jupiter of course, always appears brilliant and is usually one of the brightest nighttime objects, but in recent months it has stood out even more than usual because of the presence of bright Saturn trailing just off to its left (east).

Appearing about one-twelfth as bright, Saturn has, in a way, served as Jupiter’s “lieutenant” in this year of 2020.

An infrequent meeting

Whenever Jupiter and Saturn are in conjunction — that is, when they have the same right ascension or celestial longitude — it is referred to as a “Great Conjunction,” primarily because unlike conjunctions with the other bright planets, these two don’t get together very often. The average frequency of occurrence is merely the product of their sidereal periods divided by the absolute value of their difference.

A sidereal period is defined as the time required for a celestial body within the solar system to complete one revolution with respect to the fixed stars. Saturn’s period of 29.65 years multiplied by Jupiter’s period of 11.86 years amounts to 351.65. Dividing this value by the difference in their sidereal periods gives us 19.76 years.

So, about every 20 years, Jupiter and Saturn will have a rendezvous. The next one is coming very soon; scheduled for Dec. 21.

Exceptionally close!

The “Great Conjunction” on Dec. 21, 2020 will be a once-in-a-lifetime opportunity to see Jupiter and Saturn together through a telescope.

Most of the time, when Jupiter overtakes Saturn, they usually are separated by more than a degree. But come Dec. 21, they will be separated by just about one-tenth of a degree or 6.1 arc minutes. To gauge how close that is, on the next clear night, check out Mizar, the middle star in the handle of the Big Dipper. A fainter star, Alcor, is positioned only 11.8 arc minutes away and the ability to perceive the separation of these two stars, was once considered a test of good vision.

And yet Jupiter and Saturn will approach to within about half that distance!

That’s just 0.102 degrees

This means, under high magnification in your telescope you’ll be able to see both planets — Saturn with its famous ring system and Jupiter with its cloud bands and Galilean satellites — simultaneously in the same field of view!

How great is that?

It will be interesting to watch how the gap between these two planets will gradually close during November and December. On Nov. 1st, they are 5.1 degrees apart; by Nov. 15, 3.8 degrees. By Dec. 1, they’ll be separated by 2.2 degrees and by Dec. 15 it will be down to just 0.7 degrees, then 0.1 degrees closer each night thereafter until their long-awaited meeting on Dec. 21.

This sky map shows Jupiter and Saturn on Nov. 1, 2020.

A coalescence?

As to whether the two planets might appear as a single star, I personally can recall on June 5, 1978 when Mars and Saturn were separated by a similar distance, and yet I could clearly separate both planets with my naked eye. However, those who are near-sighted might see Jupiter and Saturn appear as one merely by removing their eyeglasses.

The last time these two planets appeared so close was on July 16, 1623, when they were only 5 arc minutes apart. We will get another 6-arc minute separation on March 15, 2080. Maybe a few of our younger readers will be around to catch that one.

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Unusual centaur emitting gas and dust

Recent arrival will provide clues to Solar System history.

This image of centaur 2014 OG392 and its extensive coma combines many digital images into a single 7700-second exposure. The dashed lines are star trails caused by the long exposure.

Astronomers and planetary scientists studying a little-known group of icy bodies called centaurs have found one that is emitting a cloud of gas and dust.

That’s unusual, says Colin Chandler, of Northern Arizona University, US, because only 17 other centaurs have ever before been observed to do so.

Studying it, he told last week’s virtual meeting of the American Astronomical Society’s Division for Planetary Sciences (DPS), will provide important clues to the make-up of these unusual bodies, and thus to the history of the early Solar System.

Centaurs are small objects whose orbits lie in the three-billion-kilometre range between Jupiter and Neptune. They are thought to have originated even farther out, in the Kuiper Belt beyond Neptune, then migrated inward millions of years ago.

They are called centaurs because they are, in many ways, hybrids.

“Centaurs have a dual nature,” says Jordan Steckloff, of the Planetary Science Institute, US, who was not part of the study team. “Just as the centaurs in lore are half-horse, half-human, the centaurs in the sky are sometimes comet-like, and sometimes asteroid-like.”

Once in the centaur belt, these objects tend to be short-lived, at least by astronomical standards. Eventually they pass too close to Jupiter, Saturn, Uranus or Neptune and either get flung into interstellar space, get sent diving toward the Sun as comets, or crash into one of the planets.

Chandler’s centaur, named 2014 OG392, is, in fact, almost certainly slated to smash into Saturn, and according to his team’s calculations could only have been in its present orbit for at most a couple of million years (and possibly only a few thousand) without already having done so.

That makes it a relatively recent arrival to the centaur belt, where even the chilly temperatures in that zone of the Solar System (2014 OG392 is estimated to have a surface temperature of minus 210 degrees Celsius) are still enough to vaporize materials that presumably were long ago lost by most other centaurs.

Figuring out what that material is, Chandler says, will provide important clues to the composition of the icy bodies farther out from the Sun. At the distance of 2014 OG392, for example, it is still far too cold for it to emitting water vapor. That should still be safely frozen, as ice.

Conversely, other ices, such as frozen carbon monoxide and methane should have warmed up and steamed away long before it got as close as it presently is. More likely, he says, it’s jetting off a mix of carbon dioxide and ammonia.

All of which may sound arcane but has huge implications for how the infant Earth received its volatiles – the chemically lightweight materials that are now the stuff of life.

One way such materials may have reached the Earth is via impacts from objects such as 2014 OG392. Thus, the more we can learn from today’s centaurs, Chandler says, the better we may be able to figure out exactly how this all-important process happened.

Meanwhile, a team led by Laura Woodney, of California State University has found another active centaur on the verge of becoming a true comet.

This object, known as P/2019 LD2, has been determined to be in a “gateway orbit” from which it is poised to be launched into the inner Solar System by gravitational interactions with Jupiter in 2063, she told the DPS meeting,

“This is the first time we’ve discovered an object that we know is going to become a comet within [at least] the lifetime of our graduate students, so we can watch this transition process,” she says.

That’s important, she adds, because up until now her team is “reasonably certain” that P/2019 LD2 has never before passed close enough to the Sun for solar heat to vaporize its water and produce the type of dramatic tail most of us identify with comets.

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Sean Robinson wrote:

Unusual centaur emitting gas and dust

This Centaur probably needs to watch its diet. maybe cut down on the mexican food and drink more water.

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Scientists detect strange ‘fast radio burst’ from within our own Milky Way

It’s a cosmic first and lasted just 1.5 milliseconds.

Mysterious superpowerful blasts of radio waves once seen only outside the galaxy have for the first time been detected within the Milky Way, new studies find.

In addition, scientists have traced these outbursts back to a rare kind of dead star known as a magnetar, the strongest magnets in the universe, for the first time.

Fast radio bursts, or FRBs, are intense pulses of radio waves that can release more energy in a few thousandths of a second than the sun does in nearly a century. Scientists only discovered FRBs in 2007, and because the bursts are so fast, astrophysicists still have many questions about them and their sources.

Scientists have dozens of theories about the causes of fast radio bursts, from colliding black holes to alien starships. Many theories suggest the bursts originate from neutron stars, which are corpses of stars that died in catastrophic explosions known as supernovas. (Their name comes from how the gravitational pulls of these stellar remnants are powerful enough to crush protons together with electrons to form neutrons.)

An artist’s impression of a magnetar in outburst, showing complex magnetic field structure and beamed emission following a crust-cracking episode.

Specifically, previous research has suggested fast radio bursts might explode from a rare type of neutron star known as a magnetar. Magnetars are the most powerful magnets in the cosmos — their magnetic fields can be up to approximately 5,000 trillion times more powerful than Earth’s.

“A magnetar is a type of neutron star whose magnetic fields are so strong, they squish atoms into pencil-like shapes,” Christopher Bochenek, an astrophysicist at the California Institute of Technology in Pasadena and lead author on one of the new studies, told Space.com.

A flash in the night

Scientists had suspected magnetars might generate fast radio bursts because prior work found that magnetars could erupt giant flares of gamma rays and X-rays. These giant flares “have a very short duration, a hard spike that lasts for milliseconds, and that is exactly the duration of FRBs,” Bing Zhang, an astrophysicist at the University of Nevada, Las Vegas and coauthor on one of the new studies, told Space.com. As such, researchers had suggested they might produce short powerful bursts of radio waves as well.

In the new studies, scientists reported that on April 28, two radio telescopes — the Survey for Transient Astronomical Radio Emission 2 (STARE2) array of three radio antennas in California and Utah, and the Canadian Hydrogen Intensity Mapping Experiment (CHIME) radio telescope in Okanagan Falls, Canada — detected a fast radio burst dubbed FRB 200428.

“This is the most luminous radio burst ever detected in our own galaxy,” Daniele Michille, an astrophysicist with CHIME and coauthor on one of the new studies, told Space.com. In the fraction of a second that this fast radio burst flashed, it was 3,000 times brighter than any other magnetar radio signal observed to date, the researchers noted.

Both arrays located the FRB in the same area of the sky. “This burst was so bright that in theory, if you had a recording of the raw data from your cell phone’s 4G LTE receiver, which does detect radio waves, and if you knew what you were looking for, you might have found this signal that came from about halfway across the galaxy in your cell phone data,” Bochanek said.

The scientists pinpointed the outburst to a magnetar known as SGR 1935+2154, located about 30,000 light-years from Earth towards the galaxy’s center in the constellation Vulpecula. This is the closest known FRB to date.

“We were able to determine that the energy of this burst is comparable to the energies of extragalactic fast radio bursts,” Bochanek added. “In about 1 millisecond, the magnetar emitted as much energy in radio waves as the sun does in 30 seconds.”

All in all, “we were able to determine the rate of these bright bursts from magnetars is consistent with the known rate of extragalactic fast radio bursts,” Bochenek said. “This discovery therefore paints the picture that some, and perhaps most, fast radio bursts from other galaxies also originate from magnetars.”

A fast radio burst mystery

Astronomers led by Zhang compared the observations with data gathered by the Five-hundred Meter Aperture Spherical Telescope (FAST) in China and did see 29 energetic gamma-ray bursts from this magnetar, but none of these coincided with any FRB seen from the magnetar. The disconnect may suggest that gamma-ray bursts from magnetars that give rise to FRBs are very special in some way, with most not doing so, Zhang said. Another possibility is that any FRBs such gamma-ray bursts generate are emitted in narrow beams pointed away from Earth, he noted.

Zhang noted there are two kinds of sources of fast radio bursts — ones that regularly generate FRBs, and ones that produce FRBs less often. If both types of fast radio burst sources are found among magnetars, that suggests two kinds of magnetars may exist: One is the kind of magnetar found in the Milky Way, which infrequently generates FRBs, and the other is more active, and perhaps consisting of newly born, rapidly rotating magnetars, Zhang said.

Future research on FRBs can pinpoint the mechanism through which magnetars or other possible bodies generate these outbursts, Zhang said.

One possibility involves randomly moving high-energy electrons generating radio waves as they interact with magnetic fields — supermassive black holes, supernova remnants and hot gas sitting in galaxies often generate radio waves this way. Another potential explanation, which Zhang favored, involves electrons as they interact en masse with magnetic fields, similar to how electronics on Earth generate radio waves by directing electrons through a wire.

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Cosmic bubbles may have forged dark matter, new theory suggests

Cosmic bubbles may have created dark matter.

Ballooning cosmic bubbles in our early universe may have led to the current abundance of dark matter, the elusive substance that tugs on the stars, yet emits no light, a new study suggests.

The theory, described Oct. 9 in the journal The Physical Review Letters, may explain exactly how dark matter condensed out of the fiery soup of the early universe. Since astronomer Fritz Zwicky first proposed the existence of dark matter in 1933, tons of observational evidence has shown that something is lurking in the shadows, invisible to our eyes and even the latest scientific instruments. Dark matter leaves its fingerprint by the gravitational tug it exerts on the visible stars and galaxies astronomers observe. The magnitude of that pull allows scientists to estimate what percentage of the universe is made of dark matter; current estimates suggest this dark material makes up 80% of the universe’s mass.

“Although we know how much dark matter our universe contains, for decades now, we’ve been left wondering about dark matter’s nature and origin,” said study co-author Andrew Long, an assistant professor of physics at Rice University in Houston. “Is dark matter a collection of elementary particles? If so, what are the properties of these particles, such as their mass and spin? What forces do these particles exert and what interactions do they experience? When was the dark matter created, and what interactions played an important role in its formation?”

Long and physicists Michael Baker, at the University of Melbourne in Australia, and Joachim Kopp, at the Johannes Gutenberg University of Mainz in Germany, wanted to answer the last of these questions — when and how did it form? They looked at the earliest period of the universe’s formation, a fraction of a nanosecond after the Big Bang started, a “Wild West” of particle creation and destruction, where particles collided and annihilated each other as quickly as they formed, Long said. At the time, the universe was a fiery soup of extremely high-energy elementary particles, similar to the quark-gluon plasma physicists create in the biggest particle accelerators today. This primordial soup was unimaginably hot and dense, and far too chaotic for more ordered subatomic particles such as protons and neutrons to form.

But this cosmic shootout did not last long. After the universe began to expand, the plasma gradually cooled and the production of new particles came to a halt. At the same time, particles grew further apart and their rate of collisions plummeted until their numbers remained fixed. The particles that were left are what scientists call “thermal relics”, and became the matter we know and love today, such as atoms, stars, and eventually, people.”In addition to all of the elementary particles known today, there’s reason to imagine there were other particles present during the early universe, such as dark matter,” Long told Live Science.

Scientists believe these hypothetical particles may also exist today as thermal relics. In the new study, the team assumed that in the fractions of a second after the Big Bang, the plasma underwent a phase transition similar to what happens now when matter moves from one state to another, such as when bubbles of water vapor form in a pot of boiling water, or steam cools down to form water droplets.

In this scenario, bubbles of cooled plasma formed abruptly in the boiling soup of the early universe. These bubbles expanded and merged until the whole universe transitioned to a new phase.

“As these droplets expanded throughout the universe, they acted like filters that sifted dark matter particles out of the plasma,” Long said. “In this way, the amount of dark matter that we measure in the universe today is a direct result of this filtration in the first fractions of a second after the Big Bang.”

The walls of these bubbles would become barriers. Only dark matter particles with large masses would have enough energy to pass through to the other side inside the expanding bubbles and escaping the Wild West that annihilated lighter particles. This would filter out lower mass dark matter particles and could explain the abundance of dark matter observed today.

The search continues

One of the leading candidates for dark matter are Weakly Interacting Massive Particles, or WIMPs. These hypothetical particles would weigh 10 to 100 times more than protons, but they would interact with matter only through two of the fundamental forces of nature: gravity and the nuclear weak force. Passing like specters through the universe, they could account for the missing dark matter astronomers, such as Zwicky, first noticed almost a century ago.

The search for WIMPs drove physicists to build enormous state-of-the-art detectors deep underground. But despite decades of searching for the elusive particles, none have been found. This led scientists in recent years to look for other dark matter particle contenders that are either lighter or heavier than WIMPs.

“One exciting aspect about the idea [of our research] is that it works for dark matter particles that are much heavier than most other candidates, such as the famous [WIMPs], on which most experimental searches in the past were focused,” Kopp, a coauthor of the paper], said in an interview. “Our work, therefore, motivates the extension of dark matter searches towards heavier masses.”

Their work could also open up the search for dark matter to other future projects such as the Laser Interferometer Space Antenna (LISA), a constellation of space probes spanning millions of miles designed to detect the ripples of gravitational waves through space.

If the cosmic bubbles envisioned by Long and colleagues were present during the early universe, they may have left a detectable fingerprint through gravitational waves, Long said. It’s possible some fraction of the energy created by two bubble walls colliding would produce gravitational waves detectable by future experiments.

The team plans to expand on their research to understand more about what happens when dark matter interacts with these bubble walls and what happens when bubbles collide. “We know dark matter is out there, but we don’t know much else,” Baker said. “If it’s a new particle, then there’s a good chance that we could actually detect it in a laboratory. We could then pin down its properties, like its mass and interactions, and learn something new and deep about the universe.”

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Asteroid Apophis is speeding up from sunlight as scientists recalculate odds of 2068 impact

‘The 2068 impact scenario is still in play,’ scientists say. But odds remain low.

ESA’s Herschel Space Observatory captured asteroid Apophis in its field of view during the approach to Earth on January, 5-6, 2013. This image shows the asteroid in Herschel’s three PACS wavelengths: 70, 100 and 160 microns.

Astronomers say they’ll have to keep an eye on the near-Earth asteroid Apophis to see how much of a danger the space rock poses to our planet during a close pass in 2068. But don’t panic: The chances of an impact still seem very low.

Under certain circumstances, the sun can heat an asteroid unevenly, causing the space rock to radiate away heat energy asymmetrically. The result can be a tiny push in a certain direction — an effect called Yarkovsky acceleration, which can change the path of an asteroid through space.

Since astronomers hadn’t measured this solar push on Apophis before, they didn’t take it into consideration when calculating the threat the asteroid poses to us in 2068. Those previous calculations showed a tiny impact probability — around 1 in 150,000.

Now, a new study shows the asteroid is drifting away from its previously predicted orbit by about 557 feet (170 meters) a year due to the Yarkovsky effect, lead author and University of Hawaii at Manoa astronomer David Tholen said during a press conference on Oct. 26.

“Basically, the heat that an asteroid radiates gives it a very tiny push,” he explained during a virtual meeting of the American Astronomical Society’s Division for Planetary Sciences. You can find the press conference on YouTube here. It begins at the 22-minute mark.

“The warmer hemisphere [of the asteroid] would be pushing slightly more than the cooler hemisphere, and that causes the asteroid to drift away from what a purely gravitational orbit would predict,” Tholen said.

Showing the orbit for the 1,120-foot-wide (340 m) Apophis, he indicated that astronomers thought they had enough observations of the asteroid — collected over the years after its discovery in 2004 — to more or less rule out an impact in 2068. Those calculations, however, were based on an orbit not affected by the sun’s energy. Ultimately, this means we can’t yet rule out Apophis being a threat in 2068, Tholen said.

“The 2068 impact scenario is still in play,” Tholen said. “We need to track this asteroid very carefully.”

Fortunately, the asteroid will make a close (yet still safe) approach to our planet in 2029, allowing ground-based telescopes — including the Arecibo Observatory’s powerful radar dish — to get a more detailed look at the asteroid’s surface and shape. Apophis will be so close it will be visible with the naked eye, at third magnitude — about as bright as the binary star Cor Caroli.

“Of all dates, Friday the 13th in April, April 13 [2029], is when the flyby will occur,” Tholen said., “Obviously, the 2029 close approach is critical. We’ll know after that occurs exactly where it [Apophis] was as it passed the Earth, and that will make it much easier for us to predict future impact scenarios.”

Tholen’s team made the discovery after four nights of observation in January and March with the Subaru Telescope, a Japanese optical-infrared telescope on the summit of Maunakea, Hawaii. The researchers collected 18 exposures of the asteroid at a very high precision, with an error of only 10 milliarcseconds in each observation. (A milliarcsecond is a thousandth of an arcsecond, an angular measurement that helps scientists measure cosmic distances.)

“We really nailed the position of this asteroid extremely well,” Tholen said. “That was enough to give us a strong detection of the Yarkovsky effect, which is something we’ve been expecting to see now for a while.”

Tholen noted that Apophis has been troublesome for astronomers, with “numerous impact scenarios” predicted (and then largely ruled out) since it was first found in 2004. For example: Initially, scientists calculated a 3% chance of Apophis slamming into our planet in 2029, a prediction Tholen said was quickly ruled out after more observations showed the true path of the little world.

If there’s any threat of an impact, astronomers will know long before 2068 how to approach the problem. Engineers around the world are developing ideas about how to deflect dangerous asteroids from our planet, concepts that range from gravitational tugs to “kinetic impactors” that would knock an incoming rock off course.

A joint European-NASA mission will also test and observe asteroid deflection at a space rock called Didymos, starting in 2022. If all goes to plan, NASA’s Double Asteroid Redirection Test (DART) spacecraft will slam into “Didymoon,” the moon orbiting Didymos. The European Space Agency will then launch the Hera mission in 2023 or 2024 and reach Didymos two years later, to see how well the kinetic impactor did in moving the moon from its previous orbit.

NASA has a dedicated Planetary Defense Coordination Office that collects asteroid observations from a network of partner telescopes, and which runs through scenarios with other U.S. agencies for asteroid deflection or (in the worst case) evacuating threatened populations from an incoming space rock. So far, decades of observations have found no imminent asteroid or comet threats to our planet.

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Jupiter’s ocean moon Europa probably glows in the dark

And the glow could tell scientists a lot about Europa’s surface composition.

This illustration of Jupiter’s moon Europa shows how the icy surface may glow on its nightside, the side facing away from the Sun. Variations in the glow and the color of the glow itself could reveal information about the composition of ice on Europa’s surface.

The icy Jupiter moon Europa is an astrobiological beacon, quite literally glowing in the deep darkness far from the sun, a new study suggests.

Jupiter’s intense radiation environment likely lights up Europa’s icy shell, which overlies a huge, potentially habitable ocean of salty liquid water, researchers have found.

“If Europa weren’t under this radiation, it would look the way our moon looks to us — dark on the shadowed side,” study lead author Murthy Gudipati, a scientist at NASA’s Jet Propulsion Laboratory (JPL) in Southern California, said in a statement. “But because it’s bombarded by the radiation from Jupiter, it glows in the dark.”

Gudipati and his team set out to study how organic molecules in Europa’s ice shell might be affected by the charged particles that zoom around Jupiter at tremendous speeds, trapped and accelerated by the giant planet’s powerful magnetic field.

The researchers built an instrument called Ice Chamber for Europa’s High-Energy Electron and Radiation Environment Testing, which they took to an electron-beam facility in Maryland. They tested the effects of radiation on simulated Europa surfaces composed of water ice and various salts suspected to be there, including sodium chloride and magnesium sulfate.

The radiation caused the samples to glow. This was not terribly surprising, the researchers said. The phenomenon is well understood: Fast-moving particles penetrated into the sample, exciting molecules in the near subsurface and generating a glow.

“But we never imagined that we would see what we ended up seeing,” study co-author Bryana Henderson, also of JPL, said in the same statement. “When we tried new ice compositions, the glow looked different. And we all just stared at it for a while and then said, ‘This is new, right? This is definitely a different glow?’ So we pointed a spectrometer at it, and each type of ice had a different spectrum.”

This nightside glow — it won’t be visible on Europa’s sun-illuminated dayside — has more than just gee-whiz appeal. Its color and intensity could reveal key details about the composition of the moon’s icy shell, study team members said.

And, because water from Europa’s buried ocean probably makes its way to the moon’s surface in places, “how that composition varies could give us clues about whether Europa harbors conditions suitable for life,” Gudipati said.

The color variation likely ranges from greenish to bluish to whitish, depending on the surface composition, team members said.

Scientists might be able to observe the glow up close relatively soon, thanks to NASA’s Europa Clipper probe, which is scheduled to launch in the mid-2020s. Clipper will orbit Jupiter but scrutinize Europa on dozens of flybys, gathering data that will help researchers assess the moon’s habitability and plan out a life-hunting Europa lander mission. (The lander has been mandated by Congress, but it remains a concept at the moment, not a full-fledged NASA mission. It will launch sometime after Clipper does.)

The Clipper team is looking at the results of the new study, which was published online Monday (Nov. 9) in the journal Nature Astronomy, to determine if Europa’s glow could be detectable by the spacecraft’s instruments, NASA officials said in the same statement.

“It’s not often that you’re in a lab and say, ‘We might find this when we get there,'” Gudipati said. “Usually it’s the other way around — you go there and find something and try to explain it in the lab. But our prediction goes back to a simple observation, and that’s what science is about.”

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Short film showing the testing they put the systems of the Perseverance rover through before sending it to Mars.

 

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Pictures from space! Our image of the day

Wednesday, November 11, 2020: The three brightest planets in the night sky flaunt their colorful features in this montage of images captured by the European Southern Observatory’s New Technology Telescope, located at the La Silla Observatory in Chile. After taking a hiatus during the coronavirus pandemic, the telescope captured these images to test out its instruments before resuming science operations.

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Physicists search for imprints left by dark matter halos as they swoosh through galactic gas

The search for dark matter – an unknown and invisible substance thought to make up the vast majority of matter in the universe – is at a crossroads. Although it was proposed nearly 70 years ago and has been searched for intensely – with large particle colliders, detectors deep underground and even instruments in space – it is still nowhere to be found.

But astronomers have promised to leave “no stone unturned” and have started to cast their net wider out into the galaxy. The idea is to extract information from astrophysical objects that may have witnessed chunks of it as they were passing by. We have just proposed a new method of doing so by tracing galactic gas – and it may help tell us what it’s actually made of.

Physicists believe that dark matter has a propensity to structure itself into a hierarchy of haloes and subhaloes, via gravity. The masses of these clumps fall on a spectrum, with lower mass ones expected to be more numerous. Is there a limit to how light they could be? It depends on the nature of the dark matter particles.

Warm versus cold

Dark matter cannot be seen directly. We know it exists because we can see the gravitational effects it has on surrounding matter. There are different theories about what dark matter may actually be. The standard model suggests it is cold, meaning it moves very slowly and only interacts with other matter through the force of gravity. This would be consistent with it being made up of particles known as axions or WIMPS. Another theory, however, suggests it is warm, meaning it moves at higher speeds. One such particle candidate is the sterile neutrino.

This artist’s impression shows the expected dark matter distribution around the Milky Way.

If dark matter is cold, a Milky Way-type galaxy could harbour one or two subhaloes weighing as much as 1010 Suns, and most likely hundreds with masses of around 108 Suns. If dark matter is warm, haloes lighter than around 108 Suns cannot form easily. So tallying light mass dark haloes can tell us something about the nature of dark matter.

Halo imprints

We believe that the existence of lower mass haloes can be revealed by carefully planned observations. Astronomers have already got pretty good at this game of hide and seek with dark matter haloes and have devised observations to pick up the damage they leave behind.

To date, observations have targeted mostly the changes in the distribution of stars in the Milky Way. For example, the Large Magellanic Cloud, a smaller galaxy orbiting ours, seems to have a dark matter halo which is massive enough to trigger an enormous wake – driving the stars from across vast regions to move in unison.

A few of the smaller dark matter haloes thought to be whizzing inside the Milky Way may occasionally pierce through large stellar features, such as globular clusters (spherical collection of stars), leaving tell-tale gaps in them. Dark matter haloes can also affect how light bends around astrophysical objects in a process called gravitational lensing.

But the signals left in the stellar distributions are weak and prone to confusion with the stars’ own motions. Another way to probe the effect of haloes is by looking at the galactic gas it affects. Galaxies have plenty of hot gas (with a temperature of around 106 degrees Kelvin) which extends out to their edge, providing a wide net for catching these dark matter haloes.

Using a combination of analytical calculations and computer simulations, we have shown that dark haloes heavier than 108 solar masses can compress the hot gas through which they are moving. These will create local spikes in the density of the gas, which can be picked up by X-ray telescopes. These are predicted to be minute, of the order of a few per cent, but they will be within the reach of the upcoming Lynx and Athena telescopes.

Our models also predict that the spikes in the density of the cooler galactic gas (with temperature of around 105 K) will be even more significant. This means that the cooler gas can record the passage of dark matter haloes even more sensitively than the hot gas.

Another promising way of observing the dark-matter-induced fluctuations in the gas is via the photons (light particles) from the cosmic microwave background – the light left over from the Big Bang. This light scatters off the highly energetic electrons in the hot gas in a way that we can detect, providing a complementary approach to the other studies.

Over the next few years, this new method can be used to test models of dark matter. Regardless of whether dark matter haloes below 108 solar masses are found in the numbers predicted or not, we will learn something useful. If the numbers match up, the standard cosmological model would have passed an important test. If they are missing, or are far fewer than expected, the standard model would be ruled out and we’ll have to find a more viable alternative.

Dark matter remains a mystery, but there’s a huge amount of work going into solving it. Whether the answer will come from instruments on Earth or astrophysical probes, it will no doubt be one of the most important discoveries of the century.

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Scientists spot a ‘kilonova’ flash so bright they can barely explain it

It may be from a magnetar born in a neutron star crash.

Scientists may have caught the blinding flash of two dense neutron stars colliding to form a strange magnetic star.

The first sign of the massive event was a gamma-ray beacon that appeared in telescope data on May 22, prompting astronomers to assemble their best instruments. That response was important: Scientists believe gamma-ray bursts usually stem from neutron stars colliding so they are eager to see as many views of such fireworks as possible. But as observations came in, researchers realized there was something strange going on: The flash included far more infrared light than predicted, 10 times more. The scientists behind the new research think that discrepancy may mean the crash produced something unexpected.

“These observations do not fit traditional explanations for short gamma-ray bursts,” Wen-fai Fong, an astronomer at Northwestern University in Illinois and lead author on the new research, said in a statement. “Given what we know about the radio and X-rays from this blast, it just doesn’t match up.”

An artist’s depiction of a brief gamma-ray burst that was 10 times brighter than the next brightest such event.of a brief gamma-ray burst that was 10 times brighter than the next brightest such event.

Astronomers used a host of facilities to study the event, including NASA’s Swift Observatory in space, the Very Large Array in New Mexico and the Keck Observatory in Hawaii, but it was the Hubble Space Telescope that spotted the extremely bright infrared radiation from the burst that told scientists something particularly strange was going on.

“The Hubble observations were designed to search for infrared emission that results from the creation of heavy elements — like gold, platinum, and uranium — during a neutron-star collision,” Edo Berger, an astronomer at the Center for Astronomy jointly run by Harvard University and the Smithsonian Institution and co-author on the new research, said in the statement. Neutron stars are the superdense remains of exploded stars and the bright afterglow from a collision of two such objects is called a kilonova.

“Surprisingly, we found much brighter infrared emission than we ever expected, suggesting that there was additional energy input from a magnetar that was the remnant of the merger,” Berger said. “The fact that we see this infrared emission, and that it is so bright shows that short gamma-ray bursts indeed form from neutron star collisions, but surprisingly the aftermath of the collision may not be a black hole, but rather likely a magnetar.”

A magnetar is a cosmic curiosity, an unusual class of supermagnetic neutron stars. But scientists have long wondered how magnetars become so magnetic, so observing a possible formation event is particularly valuable for scientists.

“We know that magnetars exist because we see them in our galaxy,” Fong said in a second statement. “We think most of them are formed in the explosive deaths of massive stars, leaving these highly magnetized neutron stars behind. However, it is possible that a small fraction form in neutron star mergers. We have never seen evidence of that before, let alone in infrared light, making this discovery special.”

And this time, researchers were able to catch an early enough view of the blast to catch the fading infrared peak in all its glory.

“Amazingly, Hubble was able to take an image only three days after the burst,” Fong said. “You need another observation to prove that there is a fading counterpart associated with the merger, as opposed to a static source. When Hubble looked again at 16 days and 55 days, we knew we had not only nabbed the fading source, but that we had also discovered something very unusual.”

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What if Earth shared its orbit with another planet?

The series “Imaginary Earths” speculates what the world might be like if one key aspect of life changed, be it related to the planet or with humanity itself.

Earth is the only planet traveling within its nearly circular orbit around the sun. But what if Earth shared its orbit with another planet?

One of the most unusual ways in which two planets might “co-orbit,” or share the same zone around their star, are so-called horseshoe orbits. Instead of both worlds moving in a circle around a star, each would move along the edge of their own somewhat horseshoe-shaped track, with these crescents facing each other like two halves of a broken ring.

“I think horseshoe orbits are among the most exciting configurations for other Earths,” astrophysicist Sean Raymond at the Laboratoire d’Astrophysique de Bordeaux in France, told Live Science. “Since the two planets formed in the same disk around the same star, and likely from similar stuff, studying their evolution is akin to studying the lives of twins separated at birth.”

The horseshoe orbits of Saturn’s moons Janus and Epimetheus.

Horseshoe orbits might sound extraordinarily unlikely. However, Saturn’s moons Janus and Epimetheus travel in horseshoe orbits about 93,000 miles (150,000 kilometers) from the planet, just beyond Saturn’s main rings, Raymond noted. The closest they get is about 9,300 miles (15,000 km) from one another.

Let’s imagine what horseshoe orbits might look like with a pair of Earth-size worlds in the sun’s habitable zone — the area surrounding a star temperate enough for liquid water to survive on a planet’s surface. Let’s name these worlds Terra and Tellus, both Latin words for “Earth.”

At their closest possible approach to each other, Terra and Tellus would come within about 4% to 5% of an astronomical unit (AU), the average distance between Earth and the sun (which is about 93 million miles, or 150 million kilometers). At such a distance, they would look as large to each other as one-quarter to one-fifth the diameter of the full moon, Raymond said. Afterwards, they would slowly recede away from each other until they passed out of sight of one another behind the sun.

“It would be awesome to see the horseshoe companion grow in the sky to become a dominant source of light,” Raymond said.

The length of these cycles of approaches and departures depends on the width of the horseshoe orbits. For Terra and Tellus, the horseshoe orbits would extend from about 0.995 AU to about 1.005 AU, so it would take about 33 years between close encounters, Raymond said. The tiny shifts in distance from the sun would likely mean the climates of Terra and Tellus would not change much as they switch between sides of their horseshoe orbits, he noted.

What might life be like on Terra and Tellus? Raymond could imagine rivalries and partnerships between the planets, including wars and star-crossed love stories. One might also imagine that long before they launched missions to one another, these worlds might engage in long-distance pen pal relationships over radio.

Horseshoe Earths would likely evolve during the course of planetary formation as protoplanets, or embryonic worlds, both having collided and migrated from one orbit to another.

“Some fraction of the time, a horseshoe configuration will pop up,” Raymond said. “Exactly how frequently this happens has never been studied carefully to my knowledge.”

Still, “even if it’s a one-in-a-million occurrence, that still leaves plenty of potential horseshoe Earths among the hundreds of billions of stars in the galaxy,” Raymond concluded.

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Earth is fighting a laser duel with the exploding Carina Nebula

Eta Carinae has been exploding for nearly 200 years, and now we’re firing lasers at it.

Lasers fly through space toward the glowing Carina Nebula

Four orange laser beams blaze through the Milky Way while an angry purple nebula transfixes us with its death-stare. Happily (or sadly, depending on how much news you’ve consumed this week), Earth is not doomed; in fact, it’s an Earthly telescope that’s launching the lasers in this epic image from the European Southern Observatory (ESO).

Dubbed ESO’s picture of the week, this shot looks like a cosmic battle to the death, but it actually captures a clever astronomical trick that scientists use to peer across time and space. The purple star system pictured here is the Carina Nebula, sometimes called the Eta Carinae nebula in honor of its most famous star system. Eta Carinae — actually a pair of two giant stars — has been steadily exploding in a spectacular eruption of gas and dust for nearly 200 years. Though the system is located about 7,500 light-years from Earth, this ever-brightening explosion has rendered it one of the most luminous star systems in the Milky Way.

The Carina Nebula sits roughly 7,500 light-years from Earth.

Seeing that far into space can be tricky, even when gazing at one of our galaxy’s brightest objects through one of Earth’s mightiest telescopes (in this case, the ESO’s Very Large Telescope, located in Chile). One niggling problem: Earth’s gassy atmosphere always gets in the way, blurring and distorting the view of celestial objects.

That’s where the lasers come in. According to the ESO, scientists fire these lasers from one of the Very Large Telescope’s component pieces to simulate distant stars. (Sodium particles in the atmosphere cause the beams to glow orange.) Astronomers then focus on these artificial stars to measure how much the beams are being blurred by Earth’s atmosphere. By practicing with fake stars, astronomers can more effectively calibrate the telescope to correct for atmospheric blurring when looking at real stars, galaxies and explosive objects like Eta Carinae, according to the ESO.

So, to summarize: Earth scientists are actively shooting lasers into the heart of an exploding star system — but only so they can get to know it better. In our strange and beautiful Milky Way, it’s just the neighborly thing to do.

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Weird ‘gravitational molecules’ could orbit black holes like electrons swirling around atoms

This computer simulation shows supermassive black holes only 40 orbits from merging.

Black holes are notable for many things, especially their simplicity. They’re just … holes. That are “black.” This simplicity allows us to draw surprising parallels between black holes and other branches of physics. For example, a team of researchers has shown that a special kind of particle can exist around a pair of black holes in a similar way as an electron can exist around a pair of hydrogen atoms — the first example of a “gravitational molecule.” This strange object may give us hints to the identity of dark matter and the ultimate nature of space-time.

Ploughing the field

To understand how the new research, which was published in September to the preprint database arXiv, explains the existence of a gravitational molecule, we first need to explore one of the most fundamental –- and yet sadly almost never talked about –- aspects of modern physics: the field.

A field is a mathematical tool that tells you what you might expect to find as you travel from place to place in the universe. For example, if you’ve ever seen a TV weather report of temperatures in your local area, you’re looking at a viewer-friendly representation of a field: As you travel around your town or state, you’ll know what kind of temperatures you’re likely to find, and where (and whether you need to bring a jacket).

This kind of field is known as a “scalar” field, because “scalar” is the fancy mathematical way of saying “just a single number.” There are other kinds of fields out there in physics-land, like “vector” fields and “tensor” fields, which provide more than one number for every location in space-time. (For example, if you see a map of wind speed and direction splashed on your screen, you’re looking at a vector field.) But for the purposes of this research paper, we only need to know about the scalar kind.

The atomic power couple

In the heydays of the mid-20th century, physicists took the concept of the field — which had been around for centuries at that point, and was absolutely old-hat to the mathematicians — and went to town with it.

They realized that fields aren’t just handy mathematical gimmicks — they actually describe something super-fundamental about the inner workings of reality. They discovered, basically, that everything in the universe is really a field.

Take the humble electron. We know from quantum mechanics that it’s pretty tough to pin down exactly where an electron is at any given moment . When quantum mechanics first emerged, this was a pretty nasty mess to understand and untangle, until the field came along.

In modern physics, we represent the electron as a field — a mathematical object that tells us where we’re likely to spot the electron the next time we look. This field reacts to the world around it — say, because of the electric influence of a nearby atomic nucleus — and modifies itself to change where we ought to see the electron.

The end result is that electrons can appear only in certain regions around an atomic nucleus, giving rise to the entire field of chemistry (I’m simplifying a bit, but you get my point).

Black hole buddies

And now the black hole part. In atomic physics, you can completely describe an elementary particle (like an electron) in terms of three numbers: its mass, its spin and its electric charge. And in gravitational physics, you can completely describe a black hole in terms of three numbers: its mass, its spin and its electron charge.

Coincidence? The jury’s out on that one, but for the time being we can exploit that similarity to better understand black holes.

In the jargon-filled language of particle physics that we just explored, you can describe an atom as a tiny nucleus surrounded by the electron field. That electron field responds to the presence of the nucleus, and allows the electron to appear only in certain regions. The same is true for electrons around two nuclei, for example in a diatomic molecule like hydrogen (H2.)

You can describe the environment of a black hole similarly. Imagine the tiny singularity at a black heart somewhat akin to the nucleus of an atom, while the surrounding environment — a generic scalar field — is similar to the one that describes a subatomic particle. That scalar field responds to the presence of the black hole, and allows its corresponding particle to appear only in certain regions. And just as in diatomic molecules, you can also describe scalar fields around two black holes, like in a binary black hole system.

The authors of the study found that scalar fields can indeed exist around binary black holes. What’s more, they can form themselves into certain patterns that resemble how electron fields arrange themselves in molecules. So, the behavior of scalar fields in that scenario mimics how electrons behave in diatomic molecules, hence the moniker “gravitational molecules.”

Why the interest in scalar fields? Well for one, we don’t understand the nature of dark matter or dark energy, and it’s possible both dark energy and dark matter could be made up of one or more scalar fields), just like electrons are made up of the electron field.

If dark matter is indeed composed of some sort of scalar field, then this result means that dark matter would exist in a very strange state around binary black holes — the mysterious dark particles would have to exist in very specific orbits, just like electrons do in atoms. But binary black holes don’t last forever; they emit gravitational radiation and eventually collide and coalesce into a single black hole. These dark matter scalar fields would affect any gravitational waves emitted during such collisions, because they would filter, deflect and reshape any waves passing through regions of increased dark matter density. This means we might be able to detect this kind of dark matter with enough sensitivity in existing gravitational wave detectors.

In short: We soon might be able to confirm the existence of gravitational molecules, and through that open a window into the hidden dark sector of our cosmos.

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The dazzling Blue Ring Nebula puzzled scientists for 16 years — and now they finally understand why

Scientists have uncovered new evidence in the mysterious fluorescent debris of the Blue Ring Nebula that may explain how the strange structure formed.

The Blue Ring Nebula harbors a central star, known as TYC 2597-735-1. An unusual ultraviolet ring surrounds the star, which astronomers first observed in 2004 using NASA’s now-defunct Galaxy Evolution Explorer (GALEX) space telescope. Until now, the formation of this peculiar ring — which is actually invisible ultraviolet light that has been color-coded blue in the telescope images — has largely remained a mystery.

“Every time we thought we had this thing figured out, something would tell us, ‘No, that’s not right,'” Mark Seibert, an astrophysicist with the Carnegie Institution for Science, a member of the GALEX team and a co-author on the new research, said in a statement. “That’s a scary thing as a scientist. But I also love how unique this object is, and the effort that so many people put in to figure it out.”

The Blue Ring Nebula is believed to have formed after a stellar collision, which ejected a cloud of hot debris into space. These emissions appear to form a ring around the nebula’s central star, as the outflow of material forms a cone shape and the base of one of the cones is oriented almost directly toward Earth.

Using the W. M. Keck Observatory in Hawaii, researchers found that the blue ring is actually the base of a cone-shaped cloud of glowing molecular hydrogen that extends away from the central star, toward Earth. The new observations also show a second cone-shaped cloud that extends from the star in the opposite direction.

The bases of the cone-shaped clouds appear to overlap when viewed from Earth, creating the ring shape around the star, Christopher Martin, a physicist at the California Institute of Technology (Caltech) and former principal investigator of GALEX, said in a news conference held digitally on Tuesday (Nov. 17), before the research was made public.

The scientists behind the new research believe that the clouds of fluorescent debris formed after a sunlike star collided with and consumed a smaller stellar companion only a few thousand years ago. The recent observations capture a never-before-seen evolutionary phase of a stellar collision.

“The merging of two stars is fairly common, but they quickly become obscured by lots of dust as the ejecta from them expands and cools in space, which means we can’t see what has actually happened,” Keri Hoadley, lead author of the study and a physicist at Caltech, said in the statement.

The timing of the new observations was critical in helping scientists understand the phenomenon. “It’s like catching sight of a baby when it first walks,” Don Neill, an astrophysicist at Caltech and a GALEX team member, said in the statement. “If you blink, you might miss it.”

It was that timing that let the researchers really see what was going on. “We think this object represents a late stage of these transient events, when the dust finally clears and we have a good view,” Hoadley said. “But we also caught the process before it was too far along; after time, the nebula will dissolve into the interstellar medium, and we would not be able to tell anything happened at all.”

The stellar collision ejected a cloud of hot debris into space. As the debris flew outward, it created a shock wave that, in turn, heated up hydrogen molecules in the debris cloud, producing the ultraviolet emissions scientists first observed back in 2004.

The researchers also used archived data from NASA’s Spitzer Space Telescope and the Wide-field Survey Explorer (WISE), which revealed an excess of infrared emissions around the central star of the Blue Ring Nebula. These observations suggest that the star is surrounded by a disk of dust that absorbs the star’s light and then reradiates in the infrared. The researchers believe that this disk cut the debris cloud surrounding the star in half, creating the two cone-shaped clouds that extend in opposite directions.

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Sean Robinson wrote:

So, to summarize: Earth scientists are actively shooting lasers into the heart of an exploding star system — but only so they can get to know it better. In our strange and beautiful Milky Way, it’s just the neighborly thing to do.

But do the Eta Carinaeans know that? In 7.500 years when the “neighbourly” beams devastate their cities, they’re going to be pissed…

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A night in the life of an astronomer. Surprising similar to a day in my life.

https://www.youtube.com/watch?v=FskFx5fbYCk

 

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Physicists discover the ‘Kings and Queens of Quantumness’

Extreme quantum states.

A conceptual image of bubbles in quantum foam.

Is that light particle more like a ball careening through space, or more of a smeary mess that is everywhere at once?

The answer depends on whether the absurd laws of subatomic particles or the deterministic equations that govern larger objects hold more sway. Now, for the first time, physicists have found a way to mathematically define the degree of quantumness that anything — be it particle, atom, molecule or even a planet — exhibits. The result suggests a way to quantify quantumness and identify “the most quantum states” of a system, which the team calls the “Kings and Queens of Quantumness.”

In addition to furthering our understanding of the universe, the work could find applications in quantum technologies such as gravitational wave detectors and ultra-precise measurement devices.

Heart of reality

At the subatomic heart of reality, the bizarre world of quantum mechanics reigns. Under these mind-bending rules, tiny subatomic particles such as electrons can be paired in strange superpositions of states — meaning that an electron can exist in multiple states at once — and their positions around an atom and even their momentums aren’t fixed until they’re observed. These teensy particles even have the ability to tunnel through seemingly insurmountable barriers.

Classical objects, on the other hand, follow the normal everyday rules of our experience. Billiard balls strike off one another; cannonballs fly along parabolic arcs; and planets spin around their orbits according to well-known physical equations.

Researchers have long pondered this odd state of affairs, where some entities in the cosmos can be defined classically, while others are subject to probabilistic quantum laws — meaning you can measure only probable outcomes.

But “according to quantum mechanics, everything is quantum mechanical,” Aaron Goldberg, a physicist at the University of Toronto in Canada and lead author of the new paper, told Live Science. “Just because you don’t see these strange things every day doesn’t mean they aren’t there.”

What Goldberg means is that classical objects like billiard balls are secretly quantum systems, so there exists some infinitesimally small probability that they will, say, tunnel through the side of a pool table. This suggests that there is a continuum, with “classicalness” on one end and “quantumness” on the other.

A little while back, one of Goldberg’s co-authors, Luis Sanchez-Soto of the Complutense University of Madrid in Spain, was giving a lecture when a participant asked him what would be the most quantum state a system could be in. “That triggered everything,” Sanchez-Soto told Live Science.

Previous attempts at quantifying quantumness always looked at specific quantum systems, like those containing particles of light, and so the outcomes couldn’t necessarily be applied to other systems that included different particles like atoms. Goldberg, Sanchez-Soto and their team searched instead for a generalized way of defining extremes in quantum states.

“We can apply this to any quantum system — atoms, molecules, light or even combinations of those things — by using the same guiding principles,” Goldberg said. The team found that these quantum extremes could come in at least two different types, naming some Kings and others Queens for their superlative nature.

They reported their findings Nov. 17 in the journal AVS Quantum Science.

So what exactly does it mean for something to be “the most quantum?” Here is where the work gets tricky, since it is highly mathematical and difficult to easily visualize.

But Pieter Kok, a physicist at the University of Sheffield in England, who was not involved in writing the new paper, suggested a way to get some grasp on it. One of the most basic physical systems is a simple harmonic oscillator — that is, a ball on the end of a spring moving back and forth, Kok told Live Science.

A quantum particle would be on the classical extreme if it behaved like this ball and spring system, found at specific points in time based on the initial kick it received. But if the particle were to be quantum mechanically smeared out so that it had no well-defined position and was found throughout the pathway of the spring and ball, it would be in one of these quantum extreme states.

Despite their peculiarity, Kok considers the results quite useful and hopes they will find widespread application. Knowing that there is a fundamental limit where a system is acting the most quantum it can is like knowing that the speed of light exists, he said.

“It puts constraints on things that are complicated to analyze,” he added.

Goldberg said that the most readily apparent applications should come from quantum metrology, where engineers attempt to measure physical constants and other properties with extreme precision. Gravitational wave detectors, for example, need to be able to measure the distance between two mirrors to better than 1/10,000th the size of an atomic nucleus. Using the team’s principles, physicists might be able to improve on this impressive feat.

But the findings could also help researchers in fields such as fiber optical communications, information processing and quantum computing. “There are probably many applications that we haven’t even thought about,” Goldberg said, excitedly.

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Faint ‘super-planet’ discovered by radio telescope for the 1st time

There are more to come

An artist’s impression of the new brown dwarf BDR J1750+3809, or “Elegast.” This faint, cold celestial body was detected using radio telescope observations for the first time.

Scientists have discovered a cold, faint “super-planet” that has remained elusive to traditional infrared survey methods.

Observations from the Low-Frequency Array, or LOFAR radio telescope, revealed a brown dwarf, which researchers have designated BDR J1750+3809 and nicknamed Elegast. Brown dwarfs are sometimes referred to as failed stars or super-planets because they are too small to be considered stars, yet too big to be considered planets.

Generally, brown dwarfs are discovered by infrared sky surveys. Elegast, however, represents the first substellar object to be detected using a radio telescope, according to a statement from the University of Hawai’i.

“This work opens a whole new method to finding the coldest objects floating in the sun’s vicinity, which would otherwise be too faint to discover with the methods used for the past 25 years,” Michael Liu, coauthor of the study and researcher from the the University of Hawai’i Institute for Astronomy, said in the statement.

Since brown dwarfs are too small to become stars, they don’t undergo the same nuclear fusion reactions that fuel bright stars, like our sun. Therefore, they are smaller, dimmer, and colder than normal stars, making them harder to find using conventional methods, such as infrared instruments. However, brown dwarfs can emit light at radio wavelengths.

The researchers first discovered Elegast using the LOFAR radio telescope based in the Netherlands. Their observations were then later confirmed using the International Gemini Observatory in Hawaii and Chile and the NASA Infrared Telescope Facility, which is operated by the University of Hawaiʻi.

“We asked ourselves, ‘Why point our radio telescope at catalogued brown dwarfs?'” Harish Vedantham, lead author of the study and astronomer from the Netherlands Institute for Radio Astronomy (ASTRON), said in the statement. “Let’s just make a large image of the sky and discover these objects directly in the radio.”

Using the LOFAR instrument to detect Elegast represents an innovative approach that could help scientists discover other celestial objects, such as gas giant exoplanets, that are too cold or faint to be detected by infrared surveys, according to the statement.

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The Laser Interferometer Gravitational-Wave Observatory (LIGO): Detecting ripples in space-time

You can’t see them, but they’re there.

An artist’s conception of two black holes merging, much like the one that produced the first detected gravitational waves.

The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a pair of enormous research facilities in the United States dedicated to detecting ripples in the fabric of space-time known as gravitational waves. Such signals come from massive objects in the universe, such as black holes and neutron stars, and provide astronomers with an entirely new window to observe cosmic phenomena.

LIGO’s underlying mechanisms rely on the work of the famous physicist Albert Einstein, who in his theory of relativity predicted the existence of gravitational waves, analogous to electromagnetic waves, more than a century ago. Einstein believed that such waves were too weak to ever be feasibly detected, according to a history of the project from the California Institute of Technology (Caltech) in Pasadena.

How LIGO detected gravitational waves

Beginning in the 1960s and 70s, researchers built prototype gravitational wave detectors using free-hanging mirrors that bounced a laser between them. If a gravitational wave passed through the apparatus, it would wiggle the fabric of space-time and cause the mirrors to move ever so slightly. This device, known as an interferometer, is still the basic unit inside today’s gravitational wave detectors.

Though those early models didn’t have the sensitivity necessary to capture a gravitational wave signal, progress continued for several decades and, in 1990, the National Science Foundation approved the assembly of two LIGO detectors; one in Hanford, Washington and another in Livingston, Louisiana.

Construction of both detectors was completed in 1999 and the search for gravitational waves began a few years later. For more than a decade, the detectors continued to come up empty, as physicists learned how to handle the highly sensitive instruments and all the things that could go wrong. Any number of things can mess with the facilities, including something as trivial as ravens pecking on the pipes leading into them.

The LIGO project operates two detector sites: one near Hanford in eastern Washington, and another near Livingston, Louisiana (shown here).

LIGO was completely redesigned for greater sensitivity between 2010 and 2014. The hard work paid off. Within days of the instruments being turned on in September 2015, the observatory began picking up the signature of its first gravitational waves, according to a LIGO fact page from Caltech.

This historic signal was kept secret for months as scientists worked to understand its details. On Feb. 11, 2016, the finding was made public, with physicists announcing that they had detected the collision of two black holes 29 and 36 times more massive than the sun, respectively, that occurred nearly 1.3 billion years ago.

The results were greeted with joy from the physics community and received widespread attention in the media. The observation not only confirmed Einstein’s century-old prediction but also provided researchers with a brand new way to peer out into the universe. A year later, astrophysicists Kip Thorne and Barry Barish of Caltech, and Rainer Weiss of MIT shared the Nobel Prize in Physics for their pioneering work on gravitational wave detection.

Related: Gravitational waves: What their discovery means for science and humanity

The LIGO collaboration currently consists of the two U.S.-based detectors as well as a third instrument that came online in 2017 called Virgo. It sits near Pisa, Italy and is run by a European group. Each facility includes an L-shaped vacuum chamber with legs 2.5 miles (4 kilometers) long containing an interferometer. The detectors’ lasers can discern movements between their mirrors with a mind-boggling accuracy of 1/10,000th the width of a proton.

Working in tandem, the three facilities help confirm that any signal one facility picks up is a true gravitational wave detection and not random noise. Researchers have created some of the quietest spots in the world around the gravitational wave detectors, slowing down nearby traffic, monitoring every tiny tremor in the ground, and even suspending the detection equipment from a pendulum system that minimizes vibrations.

LIGO’s other greatest hits

Some of LIGO and Virgo’s most spectacular results include the first detection of two neutron stars — extremely dense stellar corpses — crashing into one another. The finding, announced in October 2017, was accompanied by observations of the same event using radio, infrared, optical, gamma ray, and X-ray telescopes, allowing scientists to draw information from multiple channels — an endeavor known as multi-messenger astrophysics. The data helped prove that such collisions are the source of much of the universe’s gold, platinum and other heavy elements.

In January 2020, LIGO detected a second neutron star smashup that involved colossal objects with a combined mass 3.4 times that of the sun. Such weighty neutron stars have never before been seen in telescopes and push the size limit of what should theoretically be possible for such entities, leaving scientists to scratch their heads over how those stars could have been created.

Later that year, researchers announced that LIGO and Virgo had detected the signal of two behemoth black holes merging. The entities, which had masses 66 and 85 times that of the sun, respectively, formed a single black hole with a total mass of 142 times the sun. This was the first unambiguous evidence for what are known as intermediate mass black holes, weighing between 50 and 100,000 times the sun, which scientists knew must exist but had never before seen.

In 2020, LIGO and Virgo were joined by a Japanese instrument named the Kamioka Gravitational Wave Detector (KAGRA), though all the facilities had to be temporarily shut down due to the worldwide COVID-19 pandemic. An Indian detector is expected to join the network sometime in the mid-2020s. With these additional facilities and upgrades to the current facilities, physicists will be able to observe gravitational waves from farther away and with greater frequency, allowing them to make even more discoveries in the future.

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Newfound ‘Kraken merger’ may have been the biggest collision in Milky Way’s history

Our galaxy was built on collisions — and this one may be the largest ever.

A globular cluster (yellow) shines in the Large Magellanic cloud, one of the Milky Way’s smaller satellite galaxies.

The Milky Way contains more than 100 billion stars, but it didn’t come by them all honestly. At least a dozen times over the last 12 billion years, the Milky Way collided with a neighboring galaxy and devoured it, swallowing up that neighbor’s stars and mixing them into an ever-growing stew of pilfered suns.

With each galactic merger, the shape, size and motion of our galaxy changed forever, ultimately becoming the iconic spiral we recognize today. Now, in a recent study published in the October 2020 issue of the journal Monthly Notices of the Royal Astronomical Society, researchers have attempted to unwind that spiral. Using artificial intelligence (AI) to match distinct clusters of stars by their ages, motions and chemical compositions, the team found evidence of five large-scale galactic mergers (each involving 100 million stars or more) dating back more than 10 billion years — including one ancient collision that has never been described before.

This newfound crash with the so-called Kraken galaxy not only helps fill in the Milky Way’s mysterious family tree, but could also help astronomers piece together what our galaxy looked like in its earliest days, the study authors said.

“The collision with Kraken must have been the most significant merger the Milky Way ever experienced,” lead study author Diederik Kruijssen, an astronomer at the University of Heidelberg in Germany, said in a statement. “The merger with Kraken took place 11 billion years ago, when the Milky Way was four times less massive [than today]. As a result, the collision must have truly transformed what the Milky Way looked like at the time.”

In their new study, Kruijssen and his colleagues used computer simulations to analyze all the known globular clusters — old, dense spheres of up to 1 million stars that all formed around the same time as each other — within the Milky Way. Our galaxy hosts at least 150 of these clusters, which astronomers believe are “fossils” of the ancient galaxies that the Milky Way gobbled up over its long and hungry history.

The researchers trained an AI algorithm to identify globular clusters based on the shared properties of stars, at first running the algorithm on thousands of simulated galaxies. Once the algorithm was able to accurately predict the formation, evolution and destruction of globular clusters in those imaginary galaxies, the team set their AI loose on the Milky Way.

An image from the new study shows the five major mergers that made the Milky Way what it is today.

Using data obtained by the Gaia space probe (which has given us the most complete map of the Milky Way), the algorithm analyzed the ages, movements and chemical compositions of known globular clusters in our galaxy in order to recreate the cosmic mergers that landed them there. The team’s analysis accurately predicted four known mergers in the Milky Way’s past — including the so-called Gaia sausage merger, which added several billion stars to our galaxy’s bulge about 9 billion years ago — as well as the previously unknown Kraken merger.

And that merger was a beast. According to the team’s results, the Kraken may have been the largest and oldest galactic collision in the Milky Way’s history. The merger occurred when the Milky Way was only a fraction of its current size, and may have added to our galaxy 13 globular clusters that are still identifiable today. While the Gaia sausage merger ultimately added more solar mass to the Milky Way (more than 20 globular clusters’ worth) than did the Kraken one, our galaxy was considerably bigger when the sausage merger happened and was likely less susceptible to major structural changes, the researchers wrote.

This newfound merger is only one small piece of the puzzle. Because the road to galaxy formation is strewn with collisions like these, it’s likely that many more small-scale mergers also contributed to the Milky Way we know today. Astronomers suspect that at least 15 other mergers may be lurking in our galaxy’s past that each involved 10 million stars or more, and their remnants are just waiting to be found in our galaxy’s globular guts.

“The debris of more than five progenitor galaxies has now been identified,” Kruijssen said. “With current and upcoming telescopes, it should be possible to find [evidence of] them all.”

Astronomers have about 3 or 4 billion years to figure it out. Following that, another galaxy-altering merger will occur, when the neighboring Andromeda galaxy (currently 2.5 million light-years away) and the Milky Way will inevitably collide. Isn’t that always the way: Just when you think you know a galaxy, it goes and changes on you again.

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Dangerous ‘naked’ black holes could be hiding in the universe

Black holes are regions of infinite density, known as a singularity. And according to mainstream physics, each of these cosmic matter munchers is fringed by an event horizon –- a boundary where once you fall in, you never come out.

But what if some black holes are naked — completely lacking such frontiers? As far as we can tell, singularities are always wrapped in event horizons, but a more detailed look at the math of general relativity suggests that doesn’t have to be the case.

If such naked black holes dot the universe, new research reveals how we might be able to detect one: by looking at the ring of light surrounding it.

‘The Emperor Has No Clothes’

Black holes are a consequence of the mathematics of Einstein’s theory of general relativity. Those equations tell us that if a clump of matter collapses on itself into too small of a volume, the gravity of that matter will just keep shrinking it ever smaller until it crushes into an infinitely tiny point. That point is called a singularity, and it’s a signal that the math we’re using to describe spacetime is completely breaking down.

The gravitational pull of a singularity is infinitely strong. Objects can be pulled toward the singularity faster than the speed of light. Near a singularity, the physics of general relativity can no longer predict the future trajectory of particles — which is one of the main points of physics. Without the power to make predictions, physics falls apart.

Thankfully, as far as we know, all singularities are wrapped in an event horizon. The event horizon is the distance away from the singularity where the gravitational attraction is strong enough to pull in anything –- the point where you would have to travel faster than the speed of light to escape. That’s what makes a black hole black — even light can’t escape them.

Ever since we first discovered the existence of black holes, we’ve wondered if it’s possible to form a singularity without the associated event horizon — a so-called “naked” singularity. This would be a very dangerous place indeed, because it would be a location where the laws of physics break down that is fully accessible to the rest of the universe. At least with a traditional black hole, the singularity is safely wrapped beneath an event horizon, so even though it’s a place of extreme and unknown physics, at least whatever happens there is locked away from the rest of the cosmos.

Twisting a point

If naked singularities exist, they certainly aren’t common. We know of only one confirmed way of forming singularities, and that’s when a giant star runs out of fuel and collapses in on itself. When that happens, the singularity naturally gets an event horizon.

The presence of a naked singularity is so troubling to physicists that they’ve conjectured that perhaps nature doesn’t allow them to exist at all –- but so far we don’t have any proof of that idea.

It might be possible to form naked singularities, although only under the most extreme conditions. If a black hole is spinning, it can form a second event horizon, nestled inside the first. The faster a black hole spins, the closer these event horizons get to each other. If it spins fast enough, the mathematics predicts that the event horizons can “cancel out” (the actual physics is of course much more complicated, but you get the idea) and reveal a naked singularity.

So far, we have not identified any black holes spinning fast enough to possibly expose their singularities, but otherwise we usually have no way of determining if a random astrophysical object is a regular black hole or a naked singularity. The image provided by the Event Horizon Telescope is an exception, of course, but we don’t have a lot of pictures like that one.

Making a difference

A theoretical physicist took this challenge head-on by studying if a naked singularity could reveal itself in other ways, especially if it’s surrounded by a ring of material, as reported in a paper published Nov. 12 on the preprint journal server arXiv. This ring, called an accretion disk, is a common feature around black holes (and potentially naked singularities). When gas and dust fall onto a dense, compact object, that material flattens into a disk before funneling all the way down. This disk can be incredibly bright, betraying the existence of a black hole (in fact, this is how we know of the existence of the vast majority of the black holes in the universe).

Most theoretical studies of naked singularities have assumed that the object exists in isolation, which isn’t true in the real universe. In the new work, the theorist examined the whole, complex situation, and found a surprising result.

The accretion disk is not completely separate from the black hole (or naked singularity). The disk itself has its own gravitational pull, and it can twist and distort the compact object at the center. This distortion in turn affects the gravitational environment around the object, subtly altering the path of the material swirling inward.

The theorist found that a naked singularity does behave a little bit differently than a normal black hole –- the accretion disk around a naked singularity can be much, much brighter than around a black hole. So far our telescopes don’t have the sensitivity to tell the difference, future instruments could; perhaps an updated version of the Event Horizon Telescope would do the trick.

Finding a naked singularity out in the wild would be a major revelation in physics. We would be able to point to a location on the sky where we know that our knowledge breaks down. More detailed studies of the environment around a confirmed naked singularity would divulge some of the deepest mysteries of the universe.

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Todd

On Mars, internal heat may have powered habitable hotspots long ago

If life emerged on ancient Mars, it may have had the planet’s internal heat to thank.

A vertically exaggerated and false-color perspective of a large, water-carved channel on Mars called Dao Vallis. Whether channels like these on Mars were carved by surface water or groundwater is highly debated. The channel is about 25 miles (40 kilometers) wide, 1.6 miles (2.5 km) deep, and more than 310 miles (500 km) long.

The Martian underground may have been habitable billions of years ago even if the planet’s surface was a dry, frigid wasteland.

Mars likely churned out enough geothermal heat in the ancient past to melt the bases of thick ice sheets, generating large amounts of potentially life-supporting groundwater, a new study suggests.

The results could help scientists get a better handle on a decades-old mystery known as the faint young sun paradox. Four billion years ago, the sun was about 30% dimmer than it is today — too weak, seemingly, to support a continuously warm and wet Mars. Yet evidence of liquid water during that epoch abounds; NASA’s Mars rover Curiosity, for example, has spent the last eight years exploring an ancient lake-and-stream system. Hence the paradox.

“Even if greenhouse gases like carbon dioxide and water vapor are pumped into the early Martian atmosphere in computer simulations, climate models still struggle to support a long-term warm and wet Mars,” study lead author Lujendra Ojha, an assistant professor at Rutgers University-New Brunswick in New Jersey, said in a statement.

“I and my co-authors propose that the faint young sun paradox may be reconciled, at least partly, if Mars had high geothermal heat in its past,” Ojha said.

He and his colleagues investigated whether the required internal heat — generated by the radioactive decay of elements such as thorium, potassium and uranium — did indeed flow during Mars’ Noachian era, which lasted from about 4.1 billion to 3.7 billion years ago. The researchers focused their attention on the Martian southern highlands, a region that likely supported large ice sheets at the time.

The team modeled the thickness, behavior and evolution of those ice sheets using a variety of datasets, including observations by NASA’s Mars Odyssey orbiter, which has been studying the Red Planet since 2001. Odyssey carries a gamma-ray spectrometer, which has allowed scientists to map the abundance of thorium and potassium in the Martian crust.

The researchers determined that heat flowing from the Martian mantle and crust likely would have been sufficient to melt the bottom layers of thick ice sheets long ago, creating potentially habitable environments underground no matter what conditions may have been like on the planet’s surface.

Just what the Noachian surface was like — primarily warm and wet or mostly cold and dry, with intermittent melting spurts — remains a topic of considerable debate. But it’s widely accepted that Mars changed dramatically shortly after this era. The planet lost its global magnetic field, leaving its once-thick atmosphere vulnerable to stripping by the solar wind. Such stripping left the Martian surface cold, dry, radiation-blasted and seemingly uninhabitable, at least for Earth-like life.

But pockets of groundwater likely persisted, though they probably retreated to greater and greater depths as the surface dried out. Some of these Martian aquifers may even have survived to the present day.

“At such depths, life could have been sustained by hydrothermal activity and rock-water reactions,” Ojha said in the same statement. “So, the subsurface may represent the longest-lived habitable environment on Mars.”

The new study, which was published online today (Dec. 2) in the journal Science Advances, could have applications beyond the Red Planet. For example, the faint young sun paradox complicates our understanding of life’s emergence on the early Earth, Ojha noted. Radiogenic heat may have played a large role in making our planet habitable long ago, he said.

Similar reasoning could apply to exoplanets as well. For example, some alien worlds that seem to orbit too far from their host star to support life may actually be habitable “by their own merit, by their own radioactive heat generation,” Ojha told Space.com.

The new results don’t fully resolve the faint young sun paradox: “This is a partial solution at best,” Ojha said. He also stressed that the heat-flow numbers he and his team derived are somewhat uncertain, given that they come from elemental abundances. The researchers would love to extrapolate backward from actual measurements of Martian subsurface heat flow, he said, but no such data are available.

NASA’s InSight Mars lander, which touched down in November 2018, carries an instrument that could gather such information — a burrowing heat probe nicknamed “the mole,” which was designed to get at least 10 feet (3 meters) underground. So far, however, the Martian soil has stymied the mole’s efforts, keeping the little digger stuck at, or just below, the surface.

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Todd

Best map of Milky Way reveals a billion stars in motion – Nature

This is the most precise 3D map of the Milky Way ever made – MIT

This New 3D Map of the Universe Shows the Milky Way in Groundbreaking Detail – Thrillist

Astronomers unveil most detailed 3D map yet of Milky Way – Guardian

A ‘tsunami’ for astrophysics: New Gaia data reveals the best map of our galaxy yet – Space.com

Astronomers were hit today (Dec. 3) with a huge wave of data from the European Space Agency’s Gaia space observatory.

Those researchers can now explore the best-yet map of the Milky Way, with detailed information on the positions, distances and motion of 1.8 billion cosmic objects, to help us better understand our place in the universe.

“Gaia data is like a tsunami rolling through astrophysics,” said Martin Barstow, head of the physics and astronomy department at the University of Leicester, who is part of Gaia’s data processing team. He was speaking at a virtual news conference held today, at which another Gaia researcher, Giorgia Busso of the Leiden Observatory in the Netherlands, also told reporters that this data has produced “a revolution” in many fields of astrophysics, from the study of galactic dynamics like stellar evolution to the study of nearby objects like asteroids in the solar system.

Gaia launched in December 2013 to map the galaxy in unprecedented detail. The $1 billion spacecraft orbits the Lagrange-2, or L2, point, a spot about 1 million miles (1.5 million kilometers) away from Earth, where the gravitational forces between our planet and the sun are balanced and the view of the sky is unobstructed. Gaia can measure about 100,000 stars each minute, or 850 million objects each day, and can scan the whole sky about once every two months.

The latest trove of data improves upon the precision and scope of the two previous Gaia data sets, which were released in 2016 and 2018. For example, compared to the 2018 data, which included measurements for 1.7 billion objects, the 2020 data improves by a factor of two the accuracy of the data points for proper motion, or the apparent change in the position of a star as viewed from our solar system.

“It really gives us an insight into how the Milky Way lives,” Nicholas Walton, an astronomer at the University of Cambridge who is part of Gaia’s science team, said at the same science and news conference. “We’re talking about billions of stars, which really gives us the ability to probe at a meaningful level the whole population of the Milky Way, similar to what you’d want to do with studying people.”

Walton said the cosmic census would be like having trackers on every person in the U.K. to map their location and monitor their health. “If everyone’s got a tracker, we could tell you if they’re sweating or not. It’s a bit like that with the stars here: We can tell you which ones are sweating, which ones are active, which ones are dormant, which ones are going to die, which ones are going to explode.”

Data from Gaia has already been used across a wide range of applications over the past four years. The mission has helped researchers find the corpse of a galaxy that the Milky Way cannibalized 10 billion years ago, spot 20 hypervelocity stars unexpectedly zooming toward the galactic center, and identify about 1,000 nearby stars where hypothetical extraterrestrials would be able to see signs of life on Earth.

Closer to home, the spacecraft has allowed scientists to find previously unknown asteroids, and its precise data even allowed NASA to make a crucial, last-minute adjustment to the path of its New Horizons probe in 2018 to successfully swing past the icy rock Arrokoth, the most distant and primitive object in the solar system ever visited by a spacecraft.

So far, some 1,600 studies have been published based on Gaia data, Barstow said. More will surely result from today’s newly released material, now available on ESA’s website, and by the time the briefing for scientists and reporters ended, Walton said he expected a lot of scientists were already poring over it: “I think a lot of astronomers would have left this broadcast to go work on the data.”

This image shows the paths of 40,000 stars located within 326 light-years of our Milky Way galaxy over the next 400,000 years based on measurements and projections from the European Space Agency’s Gaia spacecraft.

Some of the new Gaia data has already been used to make discoveries. One group of researchers led by scientists at the Dresden University of Technology measured how our solar system is accelerating inside the Milky Way, using as reference points Gaia’s 1.6 million newly observed quasars, which are so far away they appear fixed in space, like galactic lighthouses.

The solar system was measured to be very slightly accelerating, as predicted by theorists, toward the galactic center. Busso said this barely perceptible acceleration only became observable in this newly released Gaia data because “the precision of the measurements increased hugely.”

These super precise tests of the way masses are distributed and accelerated are essential for “probing the limits of fundamental physics,” Gerry Gilmore, an astronomer at the University of Cambridge and a Gaia scientist, said during the event. Such measurements might help scientists understand the nature of the dark matter that we know is lurking throughout the universe.

“Even our own sun is moving so fast that our whole Milky Way would fly apart if it wasn’t held together by the dark matter, and we’ve got no idea what the dark matter is,” Gilmore said. “The hope is that by continuing experiments along the line that we’re doing — and making them more precise, and doing them on different scales — we’ll be able to see if there are different types of dark matter.”

The third Gaia data set was set to be released in 2022, but the mission scientists decided to release preliminary data now so astronomers could use it sooner, with at least two more data sets to be released in the coming years. The spacecraft will operate until at least 2022, but its mission may be extended until 2025.

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New Milky Way Map Shows Earth 2,000 Light Years Closer to Massive Black Hole Than Previously Thought – The Weather Channel

Representative Image: Like early explorers mapping the continents of our globe, astronomers are busy charting the spiral structure of our galaxy, the Milky Way

Have you ever wondered where we are placed in our home galaxy, the Milky Way, or our planet’s position with respect to the cosmic monster residing at the centre of this galaxy? There is absolutely no debate that nothing we know can escape a black hole, not even light. So, what if our planet gets too close to the massive black hole at Milky Way’s centre?

A new cosmic map has suggested that the Earth is spiralling 2,000 light-years closer to the supermassive black hole located at the centre of our Milky Way galaxy than previously thought. But don’t worry, our planet is not plunging into the black hole anytime soon as it is still thousands of light-years away from the black hole.

Where do we stand in the Milky Way?

The new map constructed by the astronomers from the National Astronomical Observatory of Japan (NAOJ) is developed using data collected over the past 15 years. It places Earth just 25,800 light-years away from the centre of the galaxy where the black hole resides.

In 1985, the International Astronomical Union estimated the official value to be around 27,700 light-years. This means that our planet is now nearly 2000 light-years closer to the black hole.

Position and velocity map of the Milky Way Galaxy. Arrows show position and velocity data for the 224 objects used to model the Milky Way Galaxy. The solid black lines show the positions of the Galaxy’s spiral arms. The colors indicate groups of objects belonging the same arm. The background is a simulation image

Based on the information obtained, the astronomers also analysed the position and velocity map of the galaxy. From this, the team calculated the centre of the galaxy—as every object in the galaxy revolves around it. The velocity component of the map suggests that Earth is travelling at 227 km/s as it orbits around the Galactic Center. This is calculated to be 7 km/s faster than the official known value of 220 km/s.

The black hole found at the centre of our galaxy is known as Sagittarius A* and is said to be 4.2 million times more massive than our Sun.

The VERA project

The map has been developed by VLBI Exploration of Radio Astrometry (VERA) project of the National Observatory of Japan. Altogether, the data from the last 15 years gives a better model of the Milky Way galaxy, in addition to the other cosmic objects studied under this project. The observations started in the year 2000. It was specially designed to map the three-dimensional velocity and spatial structures in the Milky Way, reveals the official statement.

The mapping of the Milky Way galaxy under this project is done through a series of four radio telescopes based in Japan. Specifically, it uses the technique of interferometry to combine all sets of data collected by these powerful radio telescopes to achieve the same resolution, which a single 2300 km diameter telescope could give. The observation is said to be so accurate that it could allow astronomers to capture a penny placed on the lunar surface.

The radio telescopes accurate measurement of the positions and movement of the celestial objects is important to understand the overall structure of our home galaxy and how the Earth will fare in future.

In 2020, First VERA Astrometry Catalog documented about 99 cosmic objects. For further observation, the VERA team is planning to study and calculate the distance of objects which are in particular closer to the supermassive black hole. This will help to better characterize the structure and motion of the Milky Way. The team is also planning to rope in more ground-based telescopes to acquire high-resolution maps with more accuracy.

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From interstellar space, twin Voyager probes spot ‘electron burst’

The discovery could shed new light on the mechanisms of flaring stars.

NASA’s twin Voyager spacecraft are still making discoveries more than 40 years after launching.

NASA’s twin Voyager probes keep making discoveries in interstellar space.

The Voyager mission has detected a new type of “electron burst,” which will provide insights into the mechanisms of flaring stars, a new study reports.

The bursts occur when cosmic ray electrons — fast-moving particles from far beyond the solar system — are pushed by shock waves generated by solar eruptions. The electrons then accelerate further along cosmic magnetic field lines to incredible speed, study team members said.

“The idea that shock waves accelerate particles is not new,” corresponding author Don Gurnett, professor emeritus in physics and astronomy at the University of Iowa, said in a statement. “[But] we detected it in a new realm: the interstellar medium, which is much different than in the solar wind, where similar processes have been observed.”

Both Voyager spacecraft are still going strong after 43 years in space, with each regularly sending back science to Earth from their remaining operating instruments. (Voyager 2 flew incommunicado for several months in 2020 due to planned repairs and upgrades to its radio communications facility here on Earth but made contact again in November.)

The first stage to creating the electron bursts happens with coronal mass ejections. These solar eruptions blast huge amounts of superhot plasma into space and create shock waves that move outward through the solar system.

These shock waves accelerate fast-moving cosmic-ray electrons, charged particles that likely originate from distant supernovas. The cosmic rays are further accelerated along magnetic field lines in between stars, in the interstellar medium.

Eventually, the magnetic field lines propel the cosmic rays to almost the speed of light — nearly 670 times faster than the solar shock waves that first pushed them. (The shock waves move at roughly 1 million mph, or 1.6 million kph, study team members said.)

“Physicists believe these electrons in the interstellar medium are reflected off of a strengthened magnetic field at the edge of the shock wave, and subsequently accelerated by the motion of the shock wave,” the University of Iowa said in the same release. “The reflected electrons then spiral along interstellar magnetic field lines, gaining speed as the distance between them and the shock increases.”

Voyager 1 and Voyager 2 both detected the electron bursts within days of their acceleration, and somewhat later, the two probes spotted slower, lower-energy plasma wave oscillations through the interstellar medium generated by the electron bursts.

The twin spacecraft also detected the originating solar shock wave up to a year after the event occurred; the wait time happened because the spacecraft are so far from the sun. Voyager 1 is about 14.1 billion miles (22.7 billion km) away from the sun, and Voyager 2 is about 11.7 billion miles (18.8 billion km) from our star. (The average Earth-sun distance is roughly 93 million miles, or 150 million km.)

Astronomers hope to better understand how shock waves and cosmic radiation originate from flaring stars. Solar outbursts can generate radiation that poses risks for astronauts on the International Space Station or other destinations, such as the moon (where NASA hopes to land in 2024.) Particularly violent eruptions can also threaten Earth-orbiting satellites and planetary infrastructure like power lines.

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Earth spent 500 million years creating and eating dead continents

The first half-billion years of Earth science were gnarly.

An artist’s impression shows what the surface of Earth might have looked like during the Hadean (4.6 to 4.1 billion years ago).

When Earth was just a wee young thing, it birthed many new continents — then it swallowed them all up, leaving just a few traces behind, a new study shows.

These first continents had a knack for living fast and dying young, but in doing so, they paved the way for solid continents that eventually led to the emergence of plate tectonics, the new study suggests.

“Our results explain that continents remained weak and prone to destruction in their infancy, ~4.5 to ~4.0 billion years ago, and then progressively differentiated and became rigid over the next billion years to form the core of our modern continents,” lead author Fabio Capitanio, a Monash University Earth scientist, said in a statement.

For hundreds of millions of years, the current continents have been more or less stable. They’ve moved due to plate tectonics, a theory governing the motion of Earth’s crust, forming different shapes, such as the ancient supercontinent Pangea. The puzzle pieces of the crust that existed hundreds of millions of years ago mostly still exist today. But very little is known about the continents that existed early on in Earth’s history.

To learn more about that early history, the researchers used computers to model the interactions of rock and magma in the Earth’s crust and below. The modeling showed that the earliest continents formed from parts of the upper mantle — the part of the planet just below the crust — which melted as it reached the surface and then spewed across the landscape in enormous volcanic eruptions. At that time, the planet held a vast reservoir of heat in its interior.

“The release of internal primordial heat, three to four times that of the present day, caused large melting in the shallow mantle, which was then extruded as magma (molten rock) onto the Earth’s surface,” Capitanio said.

But the continents of this period, known as the Hadean (4.6 to 4.0 billion years ago), were weak and prone to destruction.

Modern continents have a comparatively high tensile strength, meaning it’s hard to rip them apart by stretching. But the crust of the Hadean was hotter and thinner, and sat on a squishier upper mantle. So vast rifts would form between these new continents, magma would leak through, and that magma would cover the infant continents, causing the baby continents to sink into the mantle. Meanwhile, new continents were forming from the magma on top of the ones being buried.

By the time the Archean (4.0 billion to 2.5 billion years ago) began, ending the Hadean, the crust that had first formed was almost entirely replaced by the seeds of the modern continents.

In a sense, the researchers found, those lost Hadean continents made the later, more stable continents possible. The early continents’ reabsorption into the shallowest parts of the mantle made that region of the mantle dryer and firmer, forming a foundation on which later continents could safely grow.

This scenario could explain how modern plate tectonics, which relies on a firmer foundation and more structurally sound continents, emerged. The model also shows that some pieces of those early continents would remain exposed on the surface, forming stable, thick “roots” in the crust. Those pieces still exist today, and are known as cratons. One of these, Laurentia, forms the core of North America and includes a region covering the Midwest and Great Plains, as well as much of central Canada and Greenland.

The emergence of continents at the close of the Hadean also contributed fertilizer that would later help seed life on Earth, the researchers wrote. Bits of them broke off and entered the atmosphere and oceans, providing necessary nutrients for the life forms that soon emerged.

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Oops!

This is actually quite tragic, sad, and ultimately avoidable. A pity that we put more money toward building bigger and more state-of-the-art sports stadiums, but there’s never enough money to maintain valuable science infrastructure.

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[Sean Robinson]

The only total solar eclipse of 2020 occurs Monday. Here’s what to expect.

Like the previous total solar eclipse in 2019, the Dec. 14, 2020 event will happen over the Southern Cone of South America.

On Monday (Dec. 14) parts of South America will be briefly plunged into darkness by a total solar eclipse.

This relatively rare, incredible event occurs when the moon sweeps across the daytime sky and fully covers the sun’s disk as viewed from Earth, briefly blocking out the entire body of the sun except its outermost layer, called the corona. A solar eclipse produces what looks like a 360-degree sunset, and plants and animals will respond as if it was dusk.

The total solar eclipse of July 2, 2019, as seen from the La Silla Observatory in Chile.

The Dec. 14 total solar eclipse will begin in the Pacific Ocean. Then it will make landfall near Saavedra, Chile and first appear as a partial solar eclipse at 11:38 a.m. local time (9:38 a.m. EST; 1428 GMT), according to a NASA fact sheet.

Totality, when the moon completely blocks the sun, will begin in Saavedra at 1 p.m. local time (11 a.m. EST; 1600 GMT) and last for 2 minutes, 4 seconds. Closer to the center of the path of totality, eclipse viewers will see up to 2 minutes, 10 seconds of totality.

Schematic map of path of the 2020 eclipse in South America.

The roughly 56-mile-wide (90 kilometers) path of totality will travel east across Chile and Argentina. The last place to see the total eclipse before it moves off the continent and over the Atlantic Ocean will be Salina del Eje, Argentina, where totality ends at 1:25 p.m. local time (11:25 a.m. EST; 1625 GMT).

Viewers throughout most of South America will be able to view a partial solar eclipse — when the moon appears to take a “bite” out of the sun’s disk — according to NASA. Antarctica will also be exposed to up to a 40% partial solar eclipse. Above the line of totality, a partial eclipse can be seen as far north as Ecuador.

A global map of the Dec. 14, 2020 total solar eclipse.

The path of totality continues across the southern Atlantic Ocean and its stops off the coast of Namibia, according to In-The-Sky.org. Parts of the southeastern African continent, like the city of Cape Town, South Africa, will be exposed to up to a 60% partial solar eclipse shortly before sunset.

The most recent solar eclipse occurred on June 21, 2020. This annular, or “ring of fire,” eclipse didn’t fully block out the sun, but nevertheless, it dazzled spectators across parts of Africa and Asia. The last total solar eclipse happened on July 2, 2019 and, like the upcoming total eclipse, also occurred over South America.

Space.com Associate Editor Hanneke Weitering was on the scene at La Silla Observatory in Chile to capture this view of totality during the solar eclipse that occurred on July 2, 2019.

After Dec. 14, the next solar eclipse will be an annular eclipse that passes over Canada, Greenland and parts of Asia on June 10, 2021. The next total solar eclipse will appear over South America on Dec. 4, 2021.

As tempting as it might be, never look directly at a solar eclipse with naked eyes. Regular sunglasses or a telescope require a special solar filter to prevent the user from damaging their vision.

• This reply was modified 4 years, 1 month ago by Sean Robinson.
• This reply was modified 4 years, 1 month ago by Sean Robinson.

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Todd

The Geminid meteor shower, the best of 2020, peaks this weekend. Here’s what to expect.

The Geminid meteor shower, which will likely be the very best meteor display of the year, is just around the corner, predicted peak late on Sunday night (Dec. 13).

The Geminids get their name from the constellation of Gemini, the Twins. On the night of this shower’s maximum, the meteors will appear to emanate from a spot in the sky near the bright star Castor, one of two stars marking one of the heads of the twin brothers (the other being Pollux).

The Geminid meteors are the most satisfying of all the annual showers, now even surpassing the famous Perseids of August. The Geminids are also “the new kids on the block” so far as the principal meteor showers are concerned. Practically all of the other meteor displays have histories dating back many hundreds or even thousands of years. The first anecdotal account of the Leonids dates back to 902 A.D. The Perseids have been recorded since 36 A.D., and April’s Lyrids are the oldest of all, having first been recorded in Chinese chronicles as far back as 687 B.C.!

More in the link…

This sky map shows the location of the Geminid meteor shower radiant in the night sky on Dec. 13-14, 2020.

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Dec. 21: The solstice arrives at 4:47 a.m. EST (0947 GMT), marking the first day of winter in the Northern Hemisphere and the first day of summer in the Southern Hemisphere.

Dec. 21: Jupiter and Saturn will make a close approach in the evening sky — so close that they might even appear as a single “star” in the sky! The pair will be in conjunction at 8:24 a.m. EST (1324 GMT). Known as the “Great Conjunction,” this will be the closest approach of the two planets since 1623 and offers a rare, once-in-a-lifetime chance to see the two planets within the same telescopic field of view.

Dec. 21-22: The Ursid meteor shower peaks.

Dec. 23: The waxing, gibbous moon will be in conjunction with Mars at 1:31 p.m. EST (1831 GMT). Look for the pair above the eastern horizon after sunset.

Dec. 29: The full moon of December, also known as the Cold Moon, occurs at 10:28 p.m. EST (0328 GMT).

2021

Jan. 2: Happy perihelion day! Earth is farthest from the sun today.

Jan. 2-3: The Quadrantid meteor shower peaks.

Jan. 28: The Full Wolf Moon arrives at 2:16 p.m. EST (1916 GMT).

Feb. 27: The Full Snow Moon arrives at 3:17 a.m. EST (0817 GMT).

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

March 28: The Full Worm Moon arrives at 2:48 p.m. EDT (1817 GMT).

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‘Great conjunction’ of Jupiter and Saturn will form a ‘Christmas Star’ on the winter solstice

Jupiter and Saturn will have their closest encounter in almost 400 years on the solstice (Dec. 21).

On the last solstice of 2020 (Dec. 21), Jupiter and Saturn will appear the closest together in the night sky in 4 centuries.

Some parts of Earth’s Northern Hemisphere have been feeling chilly weather for weeks now, but the official beginning of winter occurs on the solstice. This is the point when the daytime is at its shortest in one hemisphere and when daytime is the longest in the other hemisphere. Dec. 21 is the summer solstice for the southern half of planet Earth.

This year, the solstice happens to converge with a “great conjunction” that some have christened as an early “Christmas star” because of its occurrence hear the holiday.

On Dec. 21, 2020, Jupiter and Saturn will appear just one-tenth of a degree apart, or about the thickness of a dime held at arm’s length, according to NASA.

A conjunction happens when planets appear incredibly close to one another in the sky because they line up with Earth in their respective orbits. Over the first three weeks of December, Saturn and Jupiter can be seen near the southwest horizon in the hour after sunset slowly getting closer with each passing night, according to a NASA skywatching statement about this month’s nocturnal highlights.

When these two planets converge on Dec. 21 they will be the closest they’ve been to one another in the night sky since 1623, according to Joe Rao, instructor at the Hayden Planetarium in New York. But that conjunction wasn’t visible to skywatchers on much of the Earth because of its location in the night sky. The last time the event was visible from most of the Earth was in 1226, according to Virginia Tech astronomer Nahum Arav.

“This rare event is special because of how bright the planets will be and how close they get to each other in the sky,” Arav said in a statement.

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This is nice. A review of Brian May’s astrophysics thesis which, incredibly, was published as a mass-market book — the reviewer can’t believe it either.

Includes suitable Queen songs where appropriate   (the review, not the thesis).

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Sean Robinson, Todd

DavidM wrote:

This is nice. A review of Brian May’s astrophysics thesis which, incredibly, was published as a mass-market book — the reviewer can’t believe it either.

It’s good to know he has another career to fall back on if the music thing doesn’t work out for him.

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Bizarre alien world may be analog of our solar system’s putative Planet Nine

HD 106906 b is interesting for many reasons.

Artist’s illustration of the exoplanet HD 106906 b located a great distance away from its central binary star and the disk of dusty material that surrounds it.

Planet Nine may not be such an oddball after all, if it does indeed exist.

The exotic exoplanet HD 106906 b is an analog of sorts of Planet Nine, the Neptune-size world hypothesized to lurk in the outer reaches of our own solar system, a new study suggests.

HD 106906 b was discovered in 2013. It’s about 11 times more massive than Jupiter and lies 336 light-years from Earth, near the double star HD 106906.

The HD 106906 stellar duo is very young — just 15 million years old — and is still surrounded by a dusty debris disk. HD 106906 b apparently emerged from that disk but is now quite removed from it, zooming along high above the disk’s plane. In addition, the giant exoplanet currently lies 737 astronomical units (AU) from the double star, about 25 times more distant from the pair than Neptune is from our sun. (One AU is the average Earth-sun distance, which is about 93 million miles, or 150 million kilometers.)

So HD 106906 b is a pretty curious character. Indeed, scientists have been debating whether the alien planet is still a bona fide member of the HD 106906 system or if it’s now speeding away from the two stars, having been booted out by a gravitational interaction.

There’s evidence that such a booting did take place: photos captured a few years ago by the Gemini South Telescope in Chile show that HD 106906’s outer dust disk and inner comet disk are lopsided. HD 106906 b could have done this sculpting if the planet formed close to the system’s center and was then kicked outward after a close encounter with the double stars, previous modeling work has indicated.

Such a disturbance would ordinarily send a planet out of its home system entirely, turning it into a “rogue” that wanders the galaxy alone, free of any host star — unless its departure was arrested by another gravitational interaction, this time with a star that wandered close to the HD 106906 system.

Last year, a group that included two of the three authors on the new study identified several stars that could have provided such a nudge about 3 million years ago. And the new paper suggests that one of those interloping stars may indeed have kept HD 106906 b from becoming a runaway.

In the new work, researchers led by Meiji Nguyen, a recent graduate of the University of California, Berkeley, analyzed observations of the HD 106906 system made between 2004 and 2018 by NASA’s Hubble Space Telescope. The astronomers also compared the Hubble images with data gathered by Europe’s Gaia spacecraft, which is precisely mapping the positions and movements of billions of stars in our Milky Way galaxy.

These combined data sets allowed the three scientists to nail down the positions of the HD 106906 binary and the giant planet. They found that HD 106906 b is likely in an elliptical and very long — but stable — orbit around its two parent stars, completing one lap every 15,000 years.

“Though it’s only been 14 years of observations, we were still able to, surprisingly, get a constraint on the orbit for the first time, confirming our suspicion that it was very misaligned and also that the planet is on an approximately 15,000-year orbit,” Nguyen said in a statement.

“The fact that our results are consistent with predictions is, I think, a strong piece of evidence that this planet is, indeed, bound. In the future, a radial-velocity measurement is needed to confirm our findings,” Nguyen added. (Radial-velocity measurements quantify the gravitational tug exerted by planets upon their host stars.)

What does this have to do with Planet Nine? The inferred history of HD 106906 b is similar to that proposed to explain how Planet Nine — or Planet Next, Planet X or Giant Planet Five, for those who will always regard Pluto as our solar system’s ninth planet — could have gotten into, and remained in, its putative orbit, a highly elliptical path that keeps it hundreds of AU from the sun.

“What I really think makes HD 106906 b unique is that it is the only exoplanet that we know that is directly imaged, surrounded by a debris disk, misaligned relative to its system and is widely separated,” Nguyen said. “This is what makes it the sole candidate we have found thus far whose orbit is analogous to the hypothetical Planet Nine.”

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Ghostly circles in the sky can’t be explained. And astronomers are excited.

Are they ‘throats’ of wormholes?

The ghostly ORC1 (blue/green fuzz), on a backdrop of the galaxies at optical wavelengths. There’s an orange galaxy at the centre of the ORC, but we don’t know whether it’s part of the ORC, or just a chance coincidence.

In September 2019, my colleague Anna Kapinska gave a presentation showing interesting objects she’d found while browsing our new radio astronomical data. She had started noticing very weird shapes she couldn’t fit easily to any known type of object.

Among them, labeled by Anna as WTF?, was a picture of a ghostly circle of radio emission, hanging out in space like a cosmic smoke-ring. None of us had ever seen anything like it before, and we had no idea what it was. A few days later, our colleague Emil Lenc found a second one, even more spooky than Anna’s.

Anna and Emil had been examining the new images from our pilot observations for the Evolutionary Map of the Universe (EMU) project, made with CSIRO’s revolutionary new Australian Square Kilometre Array Pathfinder (ASKAP) telescope.

EMU plans to boldly probe parts of the Universe where no telescope has gone before. It can do so because ASKAP can survey large swathes of the sky very quickly, probing to a depth previously only reached in tiny areas of sky, and being especially sensitive to faint, diffuse objects like these.

I predicted a couple of years ago this exploration of the unknown would probably make unexpected discoveries, which I called WTFs. But none of us expected to discover something so unexpected, so quickly. Because of the enormous data volumes, I expected the discoveries would be made using machine learning. But these discoveries were made with good old-fashioned eyeballing.

Hunting ORCs

Our team searched the rest of the data by eye, and we found a few more of the mysterious round blobs. We dubbed them ORCs, which stands for “odd radio circles”. But the big question, of course, is: “what are they?”

At first we suspected an imaging artefact, perhaps generated by a software error. But we soon confirmed they are real, using other radio telescopes. We still have no idea how big or far away they are. They could be objects in our galaxy, perhaps a few light-years across, or they could be far away in the Universe and maybe millions of light years across.

When we look in images taken with optical telescopes at the position of ORCs, we see nothing. The rings of radio emission are probably caused by clouds of electrons, but why don’t we see anything in visible wavelengths of light? We don’t know, but finding a puzzle like this is the dream of every astronomer.

We know what they aren’t

We have ruled out several possibilities for what ORCs might be.

Could they be supernova remnants, the clouds of debris left behind when a star in our galaxy explodes? No. They are far from most of the stars in the Milky Way and there are too many of them.

Could they be the rings of radio emission sometimes seen in galaxies undergoing intense bursts of star formation? Again, no. We don’t see any underlying galaxy that would be hosting the star formation.

Could they be the giant lobes of radio emission we see in radio galaxies, caused by jets of electrons squirting out from the environs of a supermassive black hole? Not likely, because the ORCs are very distinctly circular, unlike the tangled clouds we see in radio galaxies.

Could they be Einstein rings, in which radio waves from a distant galaxy are being bent into a circle by the gravitational field of a cluster of galaxies? Still no. ORCs are too symmetrical, and we don’t see a cluster at their centre.

A genuine mystery

In our paper about ORCs, which is forthcoming in the Publications of the Astronomical Society of Australia, we run through all the possibilities and conclude these enigmatic blobs don’t look like anything we already know about.

So we need to explore things that might exist but haven’t yet been observed, such as a vast shockwave from some explosion in a distant galaxy. Such explosions may have something to do with fast radio bursts, or the neutron star and black hole collisions that generate gravitational waves.

Or perhaps they are something else entirely. Two Russian scientists have even suggested ORCs might be the “throats” of wormholes in spacetime.

From the handful we’ve found so far, we estimate there are about 1,000 ORCs in the sky. My colleague Bärbel Koribalski notes the search is now on, with telescopes around the world, to find more ORCs and understand their cause.

It’s a tricky job, because ORCS are very faint and difficult to find. Our team is brainstorming all these ideas and more, hoping for the eureka moment when one of us, or perhaps someone else, suddenly has the flash of inspiration that solves the puzzle.

It’s an exciting time for us. Most astronomical research is aimed at refining our knowledge of the Universe, or testing theories. Very rarely do we get the challenge of stumbling across a new type of object which nobody has seen before, and trying to figure out what it is.

Is it a completely new phenomenon, or something we already know about but viewed in a weird way? And if it really is completely new, how does that change our understanding of the Universe? Watch this space!

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Again with the Bosons…

A new particle, the ultralight boson, could swirl around black holes, releasing detectable gravitational waves

A hypothetical particle known as the ultralight boson could be responsible for our universe’s dark matter.

While the ultralight boson isn’t directlyobservable, it might clump up around black holes, triggering an exotic mechanism that causes it to explode — in a massive burst of gravitational waves. Even better: these gravitational waves may be detectable with the next generation of detectors.

A little light reading

We don’t know what 85% of the mass in the universe is made of (thoughwe wish we did). We call it “dark matter,” but it might as well be “invisible matter,” because it doesn’t interact with light in any way, shape or form. In fact, dark matter doesn’t scatter, reflect, absorb, refract or really have anything at all to do with radiation.

But what dark matter does have is gravity. Through its gravitational pull, we can see it affect the behavior, movement and evolution of galaxies.

But what could this mysterious, invisible dark matter be? Astronomers and physicists have been puzzling over the question for decades and are slowly narrowing in on some potential answers.

Among the candidates is a hypothetical particle known as an axion. The axion was first proposed to existback in 1977, before we even knew that dark matter was a thing, and it has some properties that make it attractive and alluring as a dark matter candidate.

For one, axions can be light — very light — which makes it easy for them to flood the universe. This is exactly what we expect dark matter to be like, as it is after all the most dominant form of matter in the cosmos.

Second, the axion (and theoretical particles related to the axion, like the so-called “dark photons,” which are like axions but they can carry a hypothetical fifth force of nature) doesn’t really interact with radiation or normal matter, which is yet another criteria that would align with dark matter.

Black hole bomb

Dark matter candidate in hand, we can start looking around for reasons to think it might actually exist. Does the axion, or any of its friends, make some sort of noise or commotion that allows us to detect it?

Well, according to a paper recently appearing in the preprint journal arXiv, the axion can turn into a bomb.

And, if you ever wanted to make an axion bomb (or a “black hole bomb”), you’re in luck, because I’m about to tell you how.

First, you start with a black hole. Next, make sure the black hole is rotating. Spinning black holes can drag spacetime around them, like trying to spin a heavy coffee table on top of a rug. That rotation can transfer energy from the rotation of the black hole to any surrounding material. This can be a pretty useful energy source: just get near a black hole and use its spin to power whatever you want! (… in theory at least.)

This applies to everything — regular matter and dark matter alike. And if the dark matter is made of axions, something extra special could happen because of that rotation.

Depending on the mass of the axion particle, when they come close to a black hole (which is not a hard thing to do, because of the gravitational attraction of the black hole), it can trigger an instability.

The axions swirl around, stealing some energy from the black hole and that extra energy causes them to swirl around even faster, coming even closer to the black hole. That then pulls even more energy to the axions, causing them to swirl faster and faster.

This process is called the “superradiant instability,” but I prefer the term “black hole bomb.”

Movement in the dark

When it comes to axions (and theoretical particles like the axions), this bomb doesn’t produce a flash of light. Instead, the axions cluster around black holes in a specific configuration, arranging themselves in peaks and valleys that look almost like standing waves.

Those waves rotate with the black hole, becoming more and more energetic. The rotations release a tremendous amount of gravitational waves — the subtle ripples of gravity that constantly wash through the universe.

We’ve detected gravitational waves with instruments like LIGO and VIRGO for years now, but those instruments are tuned to the biggest energetic events, like two black holes or neutron stars colliding. But behind those super-loud events sits a general background murmur of gravitational waves. Like listening to the hubbub of a busy restaurant, that background is too faint to pick out the individual sources generating all the waves — you just have to listen to the noise.

Depending on the exact mass of an axion (the theoretical models behind axions don’t really predict a firm mass for the particle), black hole bombs could be going off all the time. While powerful, each individual event would be too faint for us to detect directly with LIGO or LISA, but it would contribute to the general background.

As of yet, there’s no evidence in the gravitational wave background for these black hole bombs — and hence no evidence linking them to the dark matter behind them. But that non-detection helps us understand these models — if the axion was heavier than a certain mass (and we’re right about how black hole bombs work), then they would’ve shown up in the background by now.

The next generation of gravitational wave detectors will be even more sensitive, and we just might see our first black hole bomb. And, along with it, our first conclusive evidence of the identity of dark matter.

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So ‘asteroid’ 2020 SO was actually 1960s space junk. It may be the first of many to come.

A diagram showing the path of 2020 SO, which is likely a Centaur upper stage from a lunar mission launched during the 1960s.

The detective story of 2020 SO, an erstwhile asteroid now formally identified as a 54-year-old piece of space junk, sounds like a wild yarn today but may become the first installment in a long series of such puzzles.

The object dubbed 2020 SO was spotted in September by an asteroid survey, but there was always something a little fishy about the space rock. One NASA expert theorized simply from its orbit that it was likely an upper-stage rocket body from the 1966 launch of a lunar mission called Surveyor 2. By the end of November, additional observations of the object had cemented its status as decades-old space junk wandering back for a surprise visit of its planet of origin. The hunk of metal made its closest approach to Earth on Dec. 1 and is expected to hang around for about four months before being kicked away to orbit the sun again.

The story of the object’s loss and rediscovery forms a stark contrast with large debris in Earth orbit, which experts monitor for their potential to collide with active satellites. “We’re so obsessively tracking everything we can in Earth orbit because we’ve created this problem with it,” Alice Gorman, an archaeologist at Flinders University in Australia focused on spaceflight heritage, told Space.com.

But not so for objects orbiting the sun. Here, records may indicate what’s been lost out in the expanse, but no one would ever waste time trying to monitor them.

“It’s kind of like they’re orphaned, they’re all by themselves in the dark and nobody is looking out for them,” Gorman said. “They’re in the darkness and then suddenly they appear in view and we’re interested in them again for a short time.”

Vishnu Reddy, who studies natural and artificial objects in Earth’s neighborhood at the University of Arizona, was interested in the object because he and his colleagues wanted to find a way to observationally confirm what precisely it was, rather than relying on 2020 SO’s strange orbit. But the object was still quite far away, and therefore difficult to see in detail.

“I looked around to find out what’s the biggest piece of telescope we can throw at it, and it turned out to be the Large Binocular Telescope,” Reddy said, referring to an observatory in Arizona with twin telescopes looking into the skies like a pair of eyes.

Despite its size, that instrument could offer only a basic, four-color spectrum for the object, which Reddy and his colleagues could compare with the two most common flavors of asteroids, carbon-based and silicate-based. No match — but that’s not a conclusive sign that the object wasn’t just a particularly weird space rock.

And so the hunt continued.

Working from the hypothesis that 2020 SO was indeed that specific upper stage from the 1966 launch, the researchers tracked down photos of the rocket before flight, then the manufacturer who supplied the white paint they saw in those images. Paint samples, the researchers applied the same four-color view — but the mystery object didn’t match that, either.

So the team reached out to a NASA historian, who said that the rocket body would have been covered in foam that fell away after launch, revealing plain stainless steel below. Same deal: find the right stainless steel, get a piece, take the four-color spectrum, check for a match. This time, tada.

Meanwhile, 2020 SO had been coming ever closer, and by mid-November, Reddy realized the team could get a proper, much more detailed spectrum by borrowing NASA’s Infrared Telescope Facility (IRTF) on Hawaii. A first try was messy, but a second observing run at the end of the month offered cleaner data. Again, the spectrum matched the stainless steel samples, but with something else mixed in.

Back to the historian the team went for one last clue; he noted that the upper stage would have had Mylar covering its electronics bay. And the spectral overlay matched the organic signature of this plastic, the researchers realized — solving the mystery.

But throughout this process, the researchers had also been looking for an even truer comparison: tracking down one of the countless Centaur upper stages that litter Earth orbit to observe in the same way as its supposed long-lost cousin.

“We don’t have that much stuff out there beyond the Earth-moon system, and it doesn’t come back that often so we don’t get the term to really have a squiz at it,” Gorman said. “We have all these other Centaurs that are in orbit as well, so we have direct comparison.”

But the Centaur Reddy and his colleagues chose to compare to 2020 SO posed its own challenges: Things orbiting Earth move very, very quickly, and IRTF has a tiny field of view, so researchers were unlikely to be able to time observations correctly and obtain a spectrum. A plan to use backyard telescopes to home in on the object failed as buildings and a recalcitrant chimney blocked the scientists’s views.

They tried anyway.

“We went to the IRTF praying, you know, give it a shot — I had like a 1% chance this would work,” Reddy said. “Sure enough it came in and the telescope operator pulled a magic miracle and he managed to grab it” — all while, in true 2020 fashion, on a video call spanning time zones to connect the collaborators.

And there it was: a perfect match. “We got a couple sets of data,” Reddy said. “Boom: Same plastic organic bands, same spectral shape, it’s like a slam dunk.”

Comparisons aside, just by popping up on scientists’ screens, 2020 SO has offered a host of new information. Even spotting it as early as scientists did, way back in September and earlier in archived images that scientists checked after the discovery, is crucial, giving scientists a sense of how strong their detection skills are.

“Frankly the fact that we can see this at a large distance is encouraging,” Paul Chodas, who leads NASA’s Center for Near Earth Object Studies and who first hypothesized that 2020 SO was the Surveyor 2 Centaur stage, told Space.com earlier this fall.

Now that the object is decisively identified, scientists can reference known statistics about its size and other characteristics and evaluate their observations to better understand real near-Earth asteroids.

In particular, the case of 2020 SO is the first time scientists have positively re-identified a lost rocket stage. The next most confident case was in September 2002, when scientists spotted what may have been the third stage of the Saturn V rocket used during the Apollo 12 mission. But two decades ago, that identification was tentative — and NASA had spotted only 2,000 near-Earth objects.

Today, that number is more than 10 times larger and is only going to keep growing. Lost space hardware wandering the sun like 2020 SO will come too, whether scientists try or not.

“We’ll get rocket bodies as a side benefit of the asteroid search missions,” Chodas said. “I certainly expect that we’ll see more examples of old hardware found in the midst of the hundreds and hundreds and in fact thousands of asteroids that we will find from the new generation of asteroid search capabilities.”

And as scientists spot more and more lost objects, these rocket parts may begin to tell more of the stories of their absence.

“I think this makes it interesting when an object like this Centaur suddenly pops back up, having having been away for a while, like a long-lost cousin, just pops out of nowhere,” Gorman said. “Suddenly, there’s an opportunity to ask it, ‘Well, what did you see while you were on that journey, in your particular little orbit?'”

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Scientists think they’ve detected radio emissions from an alien world

Similar findings may tell scientists about magnetic fields around exoplanets.

An artist’s depiction of the exoplanet Tau Boötes b shows a magnetic field, which may cause the radio emissions scientists believe they have detected.

Scientists may have detected radio emissions from a planet orbiting a star beyond our sun for the first time.

The astronomers behind the new research used a radio telescope in the Netherlands to study three different stars known to host exoplanets. The researchers compared what they saw to observations of Jupiter, diluted as if being seen from a star system dozens of light-years away. And one star system stood out: Tau Boötes, which contains at least one exoplanet. If the detection holds up, it could open the door to better understanding the magnetic fields of exoplanets and therefore the exoplanets themselves, the researchers hope.

“We present one of the first hints of detecting an exoplanet in the radio realm,” Jake Turner, an astronomer at Cornell University and lead author of the new research, said in a statement. “We make the case for an emission by the planet itself. From the strength and polarization of the radio signal and the planet’s magnetic field, it is compatible with theoretical predictions.”

However, Turner and his colleagues aren’t yet positive that the signal they detected really is coming from the planet, dubbed Tau Boötes b; the researchers called for additional observations of the system, which is about 51 light-years away from Earth in the constellation Boötes.

The new research actually began at Jupiter; the researchers had previously studied that planet’s radio emissions and then tweaked those measurements to reflect the effect they expected closeness to the host star and distance from Earth would have had on their observations of an exoplanet.

Then, the scientists consulted observations made in 2016 and 2017 by the Low Frequency Array (LOFAR) in the Netherlands. In addition to the potential signal from Tau Boötes b, the researchers also report that they may have picked up a signal from the star Upsilon Andromedae or its planet, but that detection was even fainter than the one from Tau Boötes b.

The researchers are interested in detecting radio emission from planets because such information may help scientists decipher what’s happening in the same worlds’ magnetic fields. Those magnetic fields, in turn, influence conditions on the surface of the planet — Earth’s magnetic field protects the atmosphere that makes the world one we can survive, for example. Such magnetic fields can also tell scientists about other qualities of a world, like its structure and history.

But so far, studying those magnetic fields directly has been difficult for scientists to manage, despite the fact that nearly every planet in our solar system has had one at some point in its history. Hence the interest in using radio emissions as an intermediate.

“We learned from our own Jupiter what this kind of detection looks like,” Turner said. “We went searching for it and we found it.”

But that’s just the beginning of the story, not the end of it, he emphasized, since the radio emissions could still be coming from the stars or another source instead of the planet. “There remains some uncertainty that the detected radio signal is from the planet. The need for follow-up observations is critical.”

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On the Hunt for a Missing Giant Black Hole

The mystery surrounding the whereabouts of a supermassive black hole has deepened.

Despite searching with NASA’s Chandra X-ray Observatory and Hubble Space Telescope, astronomers have no evidence that a distant black hole estimated to weigh between 3 billion and 100 billion times the mass of the Sun is anywhere to be found.

This missing black hole should be in the enormous galaxy in the center of the galaxy cluster Abell 2261, which is located about 2.7 billion light years from Earth. This composite image of Abell 2261 contains optical data from Hubble and the Subaru Telescope showing galaxies in the cluster and in the background, and Chandra X-ray data showing hot gas (colored pink) pervading the cluster. The middle of the image shows the large elliptical galaxy in the center of the cluster.

Nearly every large galaxy in the Universe contains a supermassive black hole in their center, with a mass that is millions or billions of times that of the Sun. Since the mass of a central black hole usually tracks with the mass of the galaxy itself, astronomers expect the galaxy in the center of Abell 2261 to contain a supermassive black hole that rivals the heft of some of the largest known black holes in the Universe.

Using Chandra data obtained in 1999 and 2004 astronomers had already searched the center of Abell 2261’s large central galaxy for signs of a supermassive black hole. They looked for material that has been superheated as it fell towards the black hole and produced X-rays, but did not detect such a source.

Now, with new, longer Chandra observations obtained in 2018, a team led by Kayhan Gultekin from the University of Michigan in Ann Arbor conducted a deeper search for the black hole in the center of the galaxy. They also considered an alternative explanation, in which the black hole was ejected from the host galaxy’s center. This violent event may have resulted from two galaxies merging to form the observed galaxy, accompanied by the central black hole in each galaxy merging to form one enormous black hole.

When black holes merge, they produce ripples in spacetime called gravitational waves. If the huge amount of gravitational waves generated by such an event were stronger in one direction than another, the theory predicts that the new, even more massive black hole would have been sent careening away from the center of the galaxy in the opposite direction. This is called a recoiling black hole.

Astronomers have not found definitive evidence for recoiling black holes and it is not known whether supermassive black holes even get close enough to each other to produce gravitational waves and merge; so far, astronomers have only verified the mergers of much smaller black holes. The detection of recoiling supermassive black holes would embolden scientists using and developing observatories to look for gravitational waves from merging supermassive black holes.

The galaxy at the center of Abell 2261 is an excellent cluster to search for a recoiling black hole because there are two indirect signs that a merger between two massive black holes might have taken place. First, data from the Hubble and Subaru optical observations reveal a galactic core — the central region where the number of stars in the galaxy in a given patch of the galaxy is at or close to the maximum value — that is much larger than expected for a galaxy of its size. The second sign is that the densest concentration of stars in the galaxy is over 2,000 light years away from the center of the galaxy, which is strikingly distant.

These features were first identified by Marc Postman from Space Telescope Science Institute (STScI) and collaborators in their earlier Hubble and Subaru images, and led them to suggest the idea of a merged black hole in Abell 2261. During a merger, the supermassive black hole in each galaxy sinks toward the center of the newly coalesced galaxy. If they become bound to each other by gravity and their orbit begins to shrink, the black holes are expected to interact with surrounding stars and eject them from the center of the galaxy. This would explain Abell 2261’s large core. The off-center concentration of stars may also have been caused by a violent event such as the merger of two supermassive black holes and subsequent recoil of single, larger black hole that results.

Even though there are clues that a black hole merger took place, neither Chandra nor Hubble data showed evidence for the black hole itself. Gultekin and most of his co-authors, led by Sarah Burke-Spolaor from West Virginia University, had previously used Hubble to look for a clump of stars that might have been carried off by a recoiling black hole. They studied three clumps near the center of the galaxy, and examined whether the motions of stars in these clumps are high enough to suggest they contain a ten billion solar mass black hole. No clear evidence for a black hole was found in two of the clumps and the stars in the other one were too faint to produce useful conclusions.

They also previously studied observations of Abell 2261 with the NSF’s Karl G. Jansky Very Large Array. Radio emission detected near the center of the galaxy showed evidence that supermassive black hole activity had occurred there 50 million years ago, but does not indicate that the center of the galaxy currently contains such a black hole.

They then turned to Chandra to look for material that had been superheated and produced X-rays as it fell towards the black hole. While the Chandra data did reveal that the densest hot gas was not in the center of the galaxy, they did not reveal any possible X-ray signatures of a growing supermassive black hole — no X-ray source was found in the center of the cluster, or in any of the clumps of stars, or at the site of the radio emission.

The authors concluded that either there is no black hole at any of these locations, or that it is pulling material in too slowly to produce a detectable X-ray signal.

The mystery of this gigantic black hole’s location therefore continues. Although the search was unsuccessful, hope remains for astronomers looking for this supermassive black hole in the future. Once launched, the James Webb Space Telescope may be able to reveal the presence of a supermassive black hole in the center of the galaxy or one of the clumps of stars. If Webb is unable to find the black hole, then the best explanation is that the black hole has recoiled well out of the center of the galaxy.

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Sean Robinson wrote:

Scientists think they’ve detected radio emissions from an alien world

Putting the word “alien” in that headline is a bit misleading. It’s almost as if they *want* the memes.

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Sean Robinson

‘Guardians’ of the galaxy: Space Force personnel get a name

The U.S. Space Force was officially created in December 2019.

If you thought the U.S. Space Force sounded pretty sci-fi before, well, the ante has been upped.

The nation’s newest military branch, which was officially established on Dec. 20, 2019, has decided to call its personnel “Guardians,” a move that will doubtless usher in a flood of “Guardians of the Galaxy” references and jokes.

“Henceforth, the men and women of the United States Space Force will be known as Guardians,” U.S. Vice President Mike Pence announced today (Dec. 18) during a ceremony marking the branch’s impending first anniversary.

“Soldiers, Sailors, Airmen, Marines and Guardians will be defending our nation for generations to come,” Pence added, also invoking the terms that refer to people who serve in the U.S. Army, Navy, Air Force and Marine Corps. (Service members in the nation’s other military branch, the Coast Guard, are called “Coast Guardsmen.”)

President Donald Trump directed the Department of Defense to create the Space Force when he signed Space Policy Directive-4 in February 2019. The Space Force was officially stood up 10 months later, becoming the nation’s first new military branch since the Air Force in 1947.

The Space Force is officially part of the Air Force, just as the Marine Corps is part of the Department of the Navy.

The Space Force “organizes, trains, and equips space forces in order to protect U.S. and allied interests in space and to provide space capabilities to the joint force,” the new branch’s mission statement reads. “USSF responsibilities include developing military space professionals, acquiring military space systems, maturing the military doctrine for space power and organizing space forces to present to our Combatant Commands.”

The Space Force’s creation aligns with the Trump administration’s broader space priorities, which have focused on strengthening the United States’ leadership position in space. That position is under increasing threat from China and Russia, White House and military officials have said repeatedly over the past few years.

Pence’s speech wasn’t the only Space Force action on tap today: NASA astronaut Mike Hopkins officially transferred from the Air Force to the Space Force during a ceremony aboard the International Space Station.

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The most interesting part of that report is learning that Air Force personnel are called “airmen” and not “airpersons”. I’m mildly surprised.

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Sean Robinson

I am Groot

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Scientists think they’ve spotted the farthest galaxy in the universe

GN-z11 is truly a galaxy far, far away

The galaxy GN-z11, which scientists think could be the farthest and oldest galaxy every observed, superimposed on an image from the COODS-North survey.

Astronomers have peered out into the vast expanse and spotted what they think is the farthest (and oldest) galaxy ever observed.

The galaxy GN-z11 might not have a flashy name, but it appears to be the most distant and oldest galaxy ever detected, scientists have found. Astronomers led by Nobunari Kashikawa, a professor in the department of astronomy at the University of Tokyo, embarked on a mission to find the universe’s most distant observable galaxy, to learn more about how it formed and when.

“From previous studies, the galaxy GN-z11 seems to be the farthest detectable galaxy from us, at 13.4 billion light-years, or 134 nonillion kilometers (that’s 134 followed by 30 zeros),” Kashikawa said in a statement. “But measuring and verifying such a distance is not an easy task.”

To determine how far GN-z11 is from us here on planet Earth, Kashikawa’s team studied the galaxy’s redshift — how much its light has stretched out, or shifted toward the red end of the spectrum. In general, the farther away a cosmic object is from us on Earth, the more redshifted its light will be.

Additionally, the team looked at GN-z11’s emission lines — observable, chemical signatures in the light coming from cosmic objects.

By studying these signatures closely, the team was able to figure out how far the light coming from GN-z11 must have traveled to get to us, giving them the tools to estimate its overall distance from Earth.

“We looked at ultraviolet light specifically, as that is the area of the electromagnetic spectrum we expected to find the redshifted chemical signatures,” Kashikawa said. “The Hubble Space Telescope detected the signature multiple times in the spectrum of GN-z11.”

“However,” he added, “even the Hubble cannot resolve ultraviolet emission lines to the degree we needed. So we turned to a more up-to-date ground-based spectrograph, an instrument to measure emission lines, called MOSFIRE, which is mounted to the Keck I telescope in Hawaii.”

Using MOSFIRE, the team was able to observe and study the emission lines coming from the galaxy in detail. If other observations confirm the new findings, GN-z11 would officially reign as the most distant galaxy ever seen.

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[Sean Robinson]

The moon has way (way) more craters than we thought

Scientists found more than 100,000 craters.

Locations of just some of the new moon craters. A new study has found more than 109,000 previously unknown craters on the lunar surface.

The moon has many more craters than we thought, a new study finds.

More than 109,000 new craters were discovered in the low- and mid-latitude regions of the moon using artificial intelligence (AI) that was fed data collected by Chinese lunar orbiters.

The number of craters recorded on the moon’s surface is now more than a dozen times larger than it was before. The findings were published Dec. 22 in the journal Nature Communications.

“It is the largest lunar crater database with automatic extraction for the mid- and low-latitude regions of the moon,” study lead author Chen Yang, an associate professor of Earth sciences at Jilin University in China, told Live Science in an email.

Impact craters, formed during meteor strikes, cover most of the moon’s surface.

Impact craters can be considered the lunar equivalent of “fossils,” that “record the history of the solar system,” Yang said.

Yet these “fossils” can vary dramatically in size and shape, and they can overlap and erode over time. This makes identifying and dating them extremely difficult and time-consuming. The process is also subjective, leading to inconsistencies among existing databases.

Yang and her team approached these issues with machine learning. They trained a deep neural network (where a computer uses layers of mathematical calculations that feed into each other) with data from thousands of previously identified craters and taught the algorithm to find new ones. The network was then applied to data collected by the Chang’e-1 and Chang’e-2 lunar orbiters, revealing 109,956 additional craters on the moon’s surface.

New craters found from the Nectarian System, 3.92 – 3.85 billion years old

Also (click for pics):
New craters found from the Imbrian System, 3.85 – 3.2 billion years old
– New craters found from the pre-Nectarian System which are over 3.92 billion years old
– New craters found from the Eratosthenian System, 3.2 – 1.1 billion years old
– New craters discovered from the Copernican System, younger than 1.1 billion years old

A substantial number of the craters identified in this study are classed as being “small” to “medium” in size, though from an Earthling’s perspective, they are still quite large, ranging from 0.6 miles to 60 miles (1 to 100 kilometers) in diameter. The craters’ relatively small size is likely why they weren’t detected before.

But the AI program also spotted much larger, irregularly-shaped craters that had eroded — some of those were up to 341 miles (550 km) in diameter.

The algorithm also estimated when almost 19,000 of the craters were formed based on their features, such as size and depth, and by assigning each to a geological time period. These craters spanned all five of the moon’s lunar geological periods, and some go back approximately 4 billion years.

A map of all the new moon craters according to their geological period.

The team hopes to improve their crater-spotting algorithm by feeding it data from the recently launched Chang’e 5 lander, which recently carried lunar samples back to Earth.

The researchers also want to adapt and apply their machine-learning approach to other bodies in the solar system, including planets such as Mars.

“This prediction will generally take minutes followed by a few hours of post-processing on standard computation hardware,” the researchers wrote in the study.

• This reply was modified 4 years ago by Sean Robinson.

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NASA probe snaps ‘great conjunction’ photo of Jupiter and Saturn from the moon

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Pic heavy, so I’ll split into 3 posts: 1 of 3

Here’s what we learned about aliens in 2020

An artist’s illustration of the evolution of the interstellar object ‘Oumuamua, whose weird, elongated shape may have come from tidal forces.

In a year when mysterious monoliths literally appeared out of nowhere, you’d think the first real detection of alien life would be a stone’s-throw away. Well, 2020 didn’t bring any little green men, but it did bring astronomers closer to finding extraterrestrial life than ever before. From organic molecules turning up around the solar system to mysterious radio signals finally being traced back to their source, here are some of the biggest findings of the year about where aliens may be (and definitely aren’t) hiding in the universe.

There could be alien life in the clouds of Venus

In September, Venus became the most popular planet on Earth when scientists discovered possible traces of the molecule phosphine in the planet’s atmosphere. On Earth, phosphine (made from one phosphorous atom and three hydrogen atoms) is mostly associated with non-oxygen-breathing bacteria, as well as some human activities. The molecule is produced naturally by gas giants, but there’s no good reason why it should be on the hot and hellish world of Venus, the researchers concluded — unless, perhaps, there is some sort of life breathing it into the planet’s mysterious clouds?

… But it’s not likely

Exciting as it was, the phosphine discovery was met with strong skepticism from the scientific community. For starters, it’s not even clear that the researchers detected phosphine at all; their observations contained so much noise that something mimicking phosphine’s chemical signature could have appeared by accident, John Carpenter, an observatory scientist at the Atacama telescope in Chile, previously told Live Science.

And even if the reading was accurate, phosphine could very easily be created totally randomly through a number of geological processes that don’t involve life at all, said Lee Cronin, a chemist at the University of Glasgow in the United Kingdom. The processes that shape Venus’ scorching surface and sky are largely a mystery, and one trace of an inexplicable molecule is, sadly, not enough to confirm alien life exists there. Significant study of the planet is required to solve this chemical conundrum.

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2 of 3

There could be 36 alien civilizations sharing our galaxy

How many intelligent alien civilizations are lurking among the hundreds of billions of stars in the Milky Way? According to a study published June 15 in The Astrophysical Journal, the answer is 36.

How did the researchers arrive at that number? By taking a fresh stab at a decades-old alien-hunting riddle known as the Drake equation. Named for astronomer Frank Drake, who debuted the equation in 1961, the puzzle attempts to guess the likely number of alien civilizations in our galaxy based on variables like the average rate of star formation, the percentage of stars that form planets and the much-smaller percentage of planets that have the right stuff for life. Most of these variables are still unknown, but the authors of the new study tried to resolve them with the most up-to-date information on star formation and exoplanets available.

Their result? There are precisely 36 planets in the Milky Way that could host intelligence life similar to that on Earth. But even if the researchers nailed all those unknown variables, it’ll still be a while before we meet one of our intelligence neighbors; assuming an even distribution of civilizations throughout the galaxy, the closest one is 17,000 light-years away from Earth.

And more than 1,000 alien stars could be watching us

Will they find us before we find them? We could find out in this lifetime. Two stars on the list host known exoplanets, one of which will have a direct line of sight to Earth in the year 2044.

But while we hunt for alien worlds, are aliens also hunting for us? That’s the question that motivated an Oct. 20 study in the journal Monthly Notices of the Royal Astronomical Society, in which astronomers calculated the number of alien star systems that have a direct line of sight to Earth — and therefore could be watching us right now.

The team calculated that approximately 1,000 star systems within about 300 light-years of Earth could feasibly see our planet as it passes between their location and Earth’s sun. Those sky-watching aliens would see our sun dim as Earth passes over it, just as humans have detected thousands of exoplanets by watching for suddenly-dimming stars in the night sky. What’s more, if those alien astronomers have similar technology to ours, they could even detect traces of methane and oxygen in Earth’s atmosphere, which would be potential signs of life, the researchers noted.

Aliens aren’t responsible for FRBs (at least, not this one)

Fast radio bursts (FRBs) are millisecond-long pulses of radio light that blast through space thousands of times a day. Until recently, nobody had any idea what they were. Could it be aliens, pulsing the jets on their hyper-speed spacecraft? The idea had crossed at least one astronomer’s mind. But for better or worse, that idea may be dead after astronomers successfully traced an FRB to a known source in the Milky Way for the first time ever.

The source, it turns out, was a magnetar: the fast-spinning, highly magnetized corpse of a long-dead star. For thousands of years after their formation, these temperamental objects cycle through periods of violent activity, beaming powerful pulses of X-ray and gamma-ray radiation into the universe around them at seemingly random intervals. While astronomers were watching one such outburst, they also caught an FRB beaming out of the dead star. Perhaps not all FRBs in the universe come from magnetars (aliens, you’re still on notice), but this discovery goes a long way toward solving a decade-old mystery of the cosmos.

White dwarfs may be alien strongholds

About 4 billion years from now, Earth’s sun will swell into a red giant, then collapse into a small, smoldering white dwarf. This fate is inescapable, and the odds of humankind fleeing to another star system are near-impossible. Maybe, if we’re still around at the time, we could find a way to harness the dim light of our dead star and keep on trucking as a civilization. And maybe, a paper published earlier this year to the preprint database arXiv suggests, other alien civilizations are already doing the same.

White dwarfs have been largely ignored in the search for extraterrestrial intelligence (SETI), the paper’s authors claim, as a dead star is unlikely to host a thriving civilization. But white dwarfs do sometimes have planets in their orbit – and a highly advanced civilization might be able to make their tiny sun work for them, even after death. Astronomers therefore shouldn’t cut white dwarfs out of their SETI equations, the authors write; in fact, maybe we should be looking to them first.

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3 of 3

Aliens might not breathe oxygen

Another underrated target in the search for alien life: oxygen-free planets. While it has been long assumed that alien life needs air to breathe, a study published May 4 in the journal Nature Astronomy argues that maybe “air” and “oxygen” aren’t always synonymous. Hydrogen and helium are far more common elements in our universe (Jupiter’s atmosphere is 90% hydrogen, for example), so what if an alien species evolved to breathe that stuff instead?

It turns out, it may be possible. The study authors exposed a type of non-oxygen-breathing bacteria called E. coli to two different “atmospheres” fabricated inside some test tubes. One set of flasks was pure hydrogen, the other pure helium. They found that the bacteria were able to survive in both conditions, though their growth was stunted. This experiment “opens the possibility for a much broader spectrum of habitats for life on diverse habitable worlds,” study author Sara Seager, a planetary scientist at MIT, wrote in the paper.

Aliens (probably) didn’t build ‘Oumuamua

The strange, cigar-shaped rock named ‘Oumuamua has puzzled scientists since it was first spotted in our solar system in October 2017. The object was traveling too fast to have originated in our solar system, and seemed to be accelerating for no good reason. Some astronomers — particularly Harvard University astrophysicist Avi Loeb — said it could be an alien spacecraft, powered by a paper-thin sail. That theory met with ongoing skepticism this year, however, thanks to several studies that describe the object’s potential natural origins.

One of the leading theories: ‘Oumuamua is a “hydrogen iceberg” – essentially, a solid chunk of hydrogen gas that strayed away from its local star and into the icy heart of a giant molecular cloud. After leaving the core of the cloud, the berg was battered by radiation and molded into an elongated shape. Once it entered our solar system, hydrogen began boiling off of the icy rock, causing it to accelerate without leaving a visible trail of gas. It’s a tantalizing theory that explains many of ‘Oumuamua’s quirks; still, Loeb believes aliens are the more likely explanation.

Four worlds hold the most promise

In our solar system, four worlds seem to have the right stuff for the possibility of life. The foremost is Mars — one of the most Earth-like worlds in our solar system. Earlier this year, a large lake was detected beneath the southern polar ice cap, giving new hope that tiny microbes could be present there (assuming they have something to eat).

The other three candidates are all moons: Jupiter’s moon Europa, and Saturn’s moons Enceladus and Titan. Like Mars, Europa hold the promise of water; its surface is a vast expanse of ice, which may conceal a gargantuan global ocean more than 60 miles (100 kilometers) deep. Enceladus, too, is an icy world that may holds liquid water deep beneath its surface. Recently, gargantuan geysers were spotted spraying water, grains of rocky particles and some organic molecules off of the moon and into space. Titan, meanwhile, is the only moon in our solar system with a substantial atmosphere, which is rich in nitrogen — an important building block of proteins in all known forms of life.

Alien hunting just got a little harder

On Tuesday, Dec. 1, the Arecibo Observatory’s iconic radio telescope in Puerto Rico finally collapsed, after hanging on by a literal thread for nearly five months (two mysterious cable-snapping incidents in August and November left the telescope in dire condition).

The tragic collapse ends Arecibo’s 57-year legacy of searching the cosmos for signs of extraterrestrial life. In 1974, the telescope broadcast the now-famous “Arecibo Message,” declaring the technical prowess of humanity to any intelligent extraterrestrials that might be listening. So far, there have been no answers – but that message to the stars inspired the 1997 film “Contact,” in which the Arecibo telescope plays a starring role. The telescope’s loss leaves a gap in SETI that won’t easily be filled.

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A giant black hole keeps evading detection and scientists can’t explain it

Scientists are stumped by this black hole mystery.

This composite image of the galaxy cluster Abell 2261 contains optical data from NASA’s Hubble Space Telescope and Japan’s Subaru Telescope showing galaxies in the cluster and in the background, and data from NASA’s Chandra X-ray Observatory showing hot gas (colored pink) pervading the cluster. The middle of the image shows the large elliptical galaxy in the center of the cluster.

An enormous black hole keeps slipping through astronomers’ nets.

Supermassive black holes are thought to lurk at the hearts of most, if not all, galaxies. Our own Milky Way has one as massive as 4 million suns, for example, and M87’s — the only black hole ever imaged directly — tips the scales at a whopping 2.4 billion solar masses.

The big galaxy at the core of the cluster Abell 2261, which lies about 2.7 billion light-years from Earth, should have an even larger central black hole — a light-gobbling monster that weighs as much as 3 billion to 100 billion suns, astronomers estimate from the galaxy’s mass. But the exotic object has evaded detection so far.

For instance, researchers previously looked for X-rays streaming from the galaxy’s center, using data gathered by NASA’s Chandra X-ray Observatory in 1999 and 2004. X-rays are a potential black-hole signature: As material falls into a black hole’s maw, it accelerates and heats up tremendously, emitting lots of high-energy X-ray light. But that hunt turned up nothing.

Now, a new study has conducted an even deeper search for X-rays in the same galaxy, using Chandra observations from 2018. And this new effort didn’t just look in the galaxy’s center; it also considered the possibility that the black hole was knocked toward the hinterlands after a monster galactic merger.

When black holes and other massive objects collide, they throw off ripples in space-time known as gravitational waves. If the emitted waves aren’t symmetrical in all directions, they could end up pushing the merged supermassive black hole away from the center of the newly enlarged galaxy, scientists say.

Such “recoiling” black holes are purely hypothetical creatures; nobody has definitively spotted one to date. Indeed, “it is not known whether supermassive black holes even get close enough to each other to produce gravitational waves and merge; so far, astronomers have only verified the mergers of much smaller black holes,” NASA officials wrote in a statement about the new study.

“The detection of recoiling supermassive black holes would embolden scientists using and developing observatories to look for gravitational waves from merging supermassive black holes,” they added.

Abell 2261’s central galaxy is a good place to hunt for such a unicorn, researchers said, for it bears several possible signs of a dramatic merger. For example, observations by the Hubble Space Telescope and ground-based Subaru Telescope show that its core, the region of highest star density, is much larger than expected for a galaxy of its size. And the densest stellar patch is about 2,000 light-years away from the galaxy’s center — “strikingly distant,” NASA officials wrote.

In the new study, a team led by Kayhan Gultekin from the University of Michigan found that the densest concentrations of hot gas were not in the galaxy’s central regions. But the Chandra data didn’t reveal any significant X-ray sources, either in the galactic core or in big clumps of stars farther afield. So the mystery of the missing supermassive black hole persists.

That mystery could be solved by Hubble’s successor — NASA’s big, powerful James Webb Space Telescope, which is scheduled to launch in October 2021.

If James Webb doesn’t spot a black hole in the galaxy’s heart or in one of its bigger stellar clumps, “then the best explanation is that the black hole has recoiled well out of the center of the galaxy,” NASA officials wrote.

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The Milky Way is probably full of dead civilizations

Most of the alien civilizations that ever dotted our galaxy have probably killed themselves off already.

That’s the takeaway of a new study, published Dec. 14 to the arXiv database, which used modern astronomy and statistical modeling to map the emergence and death of intelligent life in time and space across the Milky Way. Their results amount to a more precise 2020 update of a famous equation that Search for Extraterrestrial Intelligence founder Frank Drake wrote in 1961. The Drake equation, popularized by physicist Carl Sagan in his “Cosmos” miniseries, relied on a number of mystery variables — like the prevalence of planets in the universe, then an open question.

This new paper, authored by three Caltech physicists and one high school student, is much more practical. It says where and when life is most likely to occur in the Milky Way, and identifies the most important factor affecting its prevalence: intelligent creatures’ tendency toward self-annihilation.

“Since Carl Sagan’s time, there’s been lots of research,” said study co-author Jonathan H. Jiang, an astrophysicist at NASA’s Jet Propulsion Laboratory at Caltech. “Especially since the Hubble Space Telescope and Kepler Space Telescope, we have lots of knowledge about the densities [of gas and stars] in the Milky Way galaxy and star formation rates and exoplanet formation … and the occurrence rate of supernova explosions. We actually know some of the numbers [that were mysteries at the time of the famous ‘Cosmos’ episode].”

The authors looked at a range of factors presumed to influence the development of intelligent life, such as the prevalence of sunlike stars harboring Earth-like planets; the frequency of deadly, radiation-blasting supernovas; the probability of and time necessary for intelligent life to evolve if conditions are right; and the possible tendency of advanced civilizations to destroy themselves.

Modeling the evolution of the Milky Way over time with those factors in mind, they found that the probability of life emerging based on known factors peaked about 13,000 light-years from the galactic center and 8 billion years after the galaxy formed. Earth, by comparison, is about 25,000 light-years from the galactic center, and human civilization arose on the planet’s surface about 13.5 billion years after the Milky Way formed (though simple life emerged soon after the planet formed.)

In other words, we’re likely a frontier civilization in terms of galactic geography and relative latecomers to the self-aware Milky Way inhabitant scene. But, assuming life does arise reasonably often and eventually becomes intelligent, there are probably other civilizations out there — mostly clustered around that 13,000-light-year band, mostly due to the prevalence of sunlike stars there.

A figure from the paper plots the age of the Milky Way in billions of years (y axis) against distance from the galactic center (x axis), finding a hotspot for civilization 8 billion years after the galaxy formed and 13,000 light years from the galactic center.

Most of these other civilizations that still exist in the galaxy today are likely young, due to the probability that intelligent life is fairly likely to eradicate itself over long timescales. Even if the galaxy reached its civilizational peak more than 5 billion years ago, most of the civilizations that were around then have likely self-annihilated, the researchers found .

This last bit is the most uncertain variable in the paper; how often do civilizations kill themselves? But it’s also the most important in determining how widespread civilization is, the researchers found. Even an extraordinarily low chance of a given civilization wiping itself out in any given century — say, via nuclear holocaust or runaway climate change — would mean that the overwhelming majority of peak Milky Way civilizations are already gone.

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Todd

The Drake formula is an interesting thought experiment, but it is not a piece of scientific theory in any way. Any of the so-called variables could have a value of zero to infinity. There isn’t enough known about life, space or time to make it useful and the effort to do so would really not be as practical as simply pursuing any other path of practical experimentation and exploration. The basic point is to demonstrate the vast amount of unknowns that make assuming there is no other life in the universe absurd. However, at the same time, it also shows that the likelihood of any two intelligent civilizations making any contact – or to even tell if they have made contact – is almost infinitely tiny.

Kinda like the Turing Test or Chinese Box “experiments.” The point isn’t to provide a practical basis for determining artificial intelligence, but to demonstrate the difficulty in determining what intelligence, consciousness or self-awareness actually are even in people much less a machine.

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Sean Robinson wrote:

molecule phosphine

a phosphine molecule on Venus, hmmm

Maybe the Expanse became more science than Fiction

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Sean Robinson

Did a holographic phase transition in the early universe release gravitational waves?

If so, we should be able to detect these ripples in space-time in the not-too-distant future.

An artist’s illustration of two black holes merging and creating ripples in space-time known as gravitational waves.

As I’m sure you can understand, we don’t know much about the extremely early universe.

We do suspect that it went through several major transformative epochs — called phase transitions — that eventually led to the universe that we know and love. Recently, a team of physicists have used one of the most powerful tools from string theory to tackle these phase changes, and revealed that we are on the cusp of directly detecting those events through their gravitational wave signature.

A new phase

There are four known forces of nature. Two of them are very familiar to you: the force of gravity and the electromagnetic force, which combined make up the bulk of our everyday experiences. A third, the strong nuclear force, is responsible for holding atomic nuclei together, but other than that, its extremely short range prevents it from doing much else of note. The fourth, the weak nuclear force, is what makes nuclear decay and reactions possible, which is pretty handy. But otherwise, that force just sits around minding its own business.

These four forces couldn’t be any more different from each other, but one of the most remarkable insights of modern physics is that they might all be manifestations of the same force. I can’t just call that unified force “the force,” because the “Star Wars” universe already took that moniker, so we’ll have to settle for “unified force.”

We don’t know if the unified force actually exists (or ever existed), but we have been able to merge two of the forces of nature together. Inside our high-energy particle collider experiments, the electromagnetic and weak nuclear forces merge together to become a unified “electroweak” force.

And if our particle colliders can achieve this feat, then surely the universe can. When our cosmos was less than a second old, it was incredibly small, hot and dense. Small, hot and dense enough for the electroweak force to run wild. It was only once the universe expanded and cooled past this point that the forces could separate into their distinct identities.

Rough ride

In our simplest models, this transition was relatively smooth — an easy-peasy crossover from the electroweak regime to the universe of the separate electromagnetic and weak nuclear forces. But our simplest models of physics, while radically successful, do have their shortcomings. We’re not able to explain all of the variety of physics in the universe (like, say, the mass of the neutrino and the presence of dark matter) with our simple models.

More complex (and more hypothetical) models of physics predict that the phase transition that ended the electroweak epoch was very violent. Instead of one steady universal transition, it was rough and bumpy. Bubbles of new forces formed, grew and merged in a violent release of energy, with the universe erupting in chaotic fury as the electroweak force separated from itself.

But beyond the ability to say “yup, it was crazy,” the tools of modern physics aren’t up to the task of describing that violent phase transition in any more detail. Our math just isn’t good enough to track all the complex, strong forces as they transformed the universe.

String theory to the rescue.

Into the hologram.

Well, not string theory per se. String theory is our attempt to describe a unified force (and explain all of physics with one single theory), but it hasn’t been cracked — nobody has been able to solve the math of string theory in order to actually make predictions (which is kind of important for science).

But in the decades that physicists have been working to unravel the mysteries of string theory (pun intended), they stumbled across an apparently powerful technique. Some problems that seem intractably hard can be transformed into relatively simple easy-to-solve questions, then transformed back to get an answer.

The catch: you have to think in higher dimensions. In our case of trying to understand the nastiness of the early universe, the hard (and possibly impossible) math behind the physics of the phase transition can be transformed into a simpler problem involving general relativity — in five dimensions.

It doesn’t make any sense. Why does this trick work? Why do electroweak problems in four dimensions become gravity problems in five? We don’t know. But we do know that this approach just might be crazy enough to work, and a team of theoretical physicists have used this approach to model the physics of the early universe, as reported in a paper recently appearing on the preprint journal arXiv.

Armed with this newfangled “holographic” (as the technique is called, because it involves translating from one set of dimensions to another without losing information) trick, the theorists were able to track the formation of bubbles during the electroweak phase transition. They found that bubble formation and collision results in a tremendous release of gravitational waves.

Those ripples in space-time can persist to the present day. But even though they would’ve torn you up like a piece of paper when they first formed, nowadays they can barely nudge an atom. We don’t yet have the sensitivity to detect them, but the researchers found that proposed space-based gravitational wave detectors, like the European Space Agency’s Laser Interferometer Space Antenna mission, or LISA, will.

When LISA is fully operational (which will take another couple decades at least), it’s possible that it could detect these faint gravitational waves that are left over from when the last of the four forces of nature split from each other. Without holographic theory, we would never have been able to make this sort of prediction, and the earliest and most violent epochs in the history of the cosmos would still remain a mystery.

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Sean Robinson wrote:

“Earth has a metal core, a mantle and crust. It’s possible that as a Psyche protoplanet was forming, it was struck by another object in our solar system and lost its mantle and crust,” Becker said.

It is interesting to think that if it was possible to drill miles down into the earth from any point, you’d find all sorts of rare metals and crystals worth billions.

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Anonymous wrote:

Sean Robinson wrote:

“Earth has a metal core, a mantle and crust. It’s possible that as a Psyche protoplanet was forming, it was struck by another object in our solar system and lost its mantle and crust,” Becker said.

It is interesting to think that if it was possible to drill miles down into the earth from any point, you’d find all sorts of rare metals and crystals worth billions.

I’ll get my shovel!

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Pictures from space! Our image of the day

Neon lights

Jan. 11, 2021: This strange, green glow is actually a new type of star that, until recently, hadn’t been observed in X-ray light. Scientists think that this star formed when two white dwarf stars (the leftover stellar cores of stars like our sun) merged into one another, forming a new object that emits X-ray light instead of being destroyed in the collision.

Galactic fireworks

Jan. 8, 2021: The galaxy NGC 6946, nicknamed “the Fireworks Galaxy,” can be seen in this stunning image from the NASA/ESA Hubble Space Telescope. The galaxy got its explosive nickname because, while our Milky Way galaxy has an average of just 1-2 supernovas per century, NGC 6946 has had 10 in the last century.

“The Fireworks Galaxy,” the structure of which is somewhere between a full spiral and a barred spiral, can be found 25.2 million light-years from Earth on the border of the constellations Cepheus and Cygnus.

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A mysterious ‘wobble’ is moving Mars’ poles around

Like a teetering top, Mars refuses to rotate on a straight axis.

Mars and its two moons, Phobos and Deimos

The Red Planet is wiggling and wobbling as it spins, research in the journal Geophysical Research Letters confirms, and astronomers have no idea why.

Like a toy top that teeters as it loses speed, the poles of Mars are wandering ever-so-slightly away from the planet’s axis of rotation, moving about 4 inches (10 centimeters) off-center every 200 days or so, researchers reported in a study published Oct. 13, 2020. That makes Mars only the second known planet in the universe to exhibit this phenomenon — known as the Chandler wobble — with Earth being the first, according to the American Geophysical Union’s (AGU) news blog, Eos.org.

This wobble — named for astronomer Seth Carlo Chandler, who discovered the phenomenon more than a century ago — is an effect seen in planets that aren’t perfectly round, science writer Jack Lee wrote at Eos. On Earth, the wobble is much more pronounced: Our planet’s poles wander roughly 30 feet (9 m) from its axis of rotation, wobbling in a circular pattern that repeats every 433 days or so.

This wonky wobble has negligible effect on our planet, according to Eos, but still presents a puzzle. Scientists have calculated that the wobble should naturally die down within a century of its origin, but our planet’s current wobble has been going strong for much longer than that. Something — perhaps a combination of pressure changes in the atmosphere and oceans, one 2001 study proposed — seems to be perpetually reigniting the wobble, though the exact mechanism is still unknown.

The Mars wobble is just as puzzling. The authors of the new study detected the wobble using 18 years of data collected by three satellites orbiting the Red Planet: Mars Odyssey, Mars Reconnaissance Orbiter and Mars Global Surveyor. This small shift in the Martian poles should also resolve itself naturally, the team calculated, but currently appears to be going strong.

Devoid of oceans, Mars and its wobbly rotation may be governed by atmospheric pressure changes alone, according to Eos, but further study of our tipsy neighbor is required to know for sure.

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I count nine uses of the word “wobble”, two “wobbling” and one “wobbly”. Get better writers, space.com!

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‘Super Bowl of Astronomy’ kicks off online due to global pandemic

The 237th American Astronomical Society meeting, the “Super Bowl of astronomy,” will be held entirely online this week, a first, due to the coronavirus pandemic.

The American Astronomical Society (AAS) is making the most of online opportunities during its 237th meeting, which will fully take place virtually this week due to the coronavirus pandemic.

The self-proclaimed “Super Bowl of Astronomy,” which runs through Friday (Jan. 15), typically covers a wide range of topics, and this year’s edition will be no different even though it will be fully online. The full agenda is available here. Some hot topics attendees can expect include fast radio bursts, dark matter, sky surveys, gravitational waves, and trying to understand why different teams have different measurements to calculate the expansion of the universe, among others.

AAS was already including iPosters (PowerPoint-like posters with combinations of text, images, video and audio) at its in-person meetings, along with short science talks, before the pandemic erupted last March. The society tested these meeting formats online with the June 2020 meeting, which was quickly moved online only weeks before starting as quarantine restrictions expanded across the United States.

Attendees can expect even more adaptations to online for AAS 237, press officer Rick Fienberg told Space.com in an e-mail interview.

“For AAS 237, we are adding ‘Turbo Talks’ – 2-minute introductory videos by authors to draw attention and spur interest in their iPosters,” he said. Other changes attendees can expect include Slack channels during the talks for people to “kibitz”, Fienberg said, and spreading the meeting over five days instead of four to reduce the time attendees must spend at the computer each day.

The virtual exhibition hall will be very different than what attendees saw in June. This time around, AAS will use a meeting environment called vFairs, which allows sponsors and exhibitors to create custom-branded virtual booths, Fienberg said.

“They can post brochures and other files for download, have staff at the booth at certain times of day to interact with attendees one-on-one or in small groups, and offer webinars to introduce larger audiences of attendees to their products and services,” he said.

Coronavirus and space: How the pandemic is affecting research and missions

The ultimate goal is to attract more attendees to the virtual exhibition hall, mirroring the “coffee break” and “cocktail hour” experience one typically gets by wandering into the physical hall during an in-person meeting, he added.

“At our first virtual meeting in June, exhibitors didn’t get the traffic they’re used to, for obvious reasons,” Fienberg said. “So for January, we’ve set aside some dedicated time each day where the only activity is in the exhibit hall, and we’ve successfully encouraged nearly all our exhibitors to offer webinars, which are being listed in the program along with everything else so as not to get lost in the shuffle.”

Student attendees can also look forward to the first-ever virtual “graduate school” and undergraduate research “experience fair” which will allow students to share CVs, meeting via text and video chat, and learn more about participating institutions – all without the need of paying for in-person travel. People at all stages of their career can also take advantage of various social networking events, such as a trivia night, speed networking and a virtual scavenger hunt.

Looking back at the June meeting, Fienberg said the AAS staff “really had to scramble” to shift all activities online, including assembling the infrastructure, find vendors, and to bring members and other stakeholders along for the ride. The hard work paid off, as roughly 1,400 people attended the virtual activities – double the expected attendance AAS thought it would see in-person in Madison, Wisc.

Fienberg said AAS has listened closely to attendee feedback in June to prepare for January; another change they are making is including two days of workshops that were not offered in June. The winter meeting typically has higher attendance than the summer meeting, with more sessions and activities as well.

“With five days of science sessions and two slots daily for press conferences, I’ve scheduled 10 briefings rather than my usual eight, so I have 25% more presenters to communicate with – plus their institutional public information officers,” Fienberg said. “All of us involved in planning and executing the meeting are really quite exhausted already, but that’s true when doing in-person meetings too. What we’ve learned over these two meetings is that a virtual meeting involves just as much work as an in-person one.”

Fienberg added that some attendees have expressed worry about high registration fees for the virtual meeting, but he noted the infrastructure is not free. While venues and caterers are not required for online conferences, AAS is still working with vendors and software to deliver the best experience possible. “It’s a fairly even trade,” he said of the cost to AAS.

With a vaccine slowly rolling out in the United States and other countries, AAS is thinking ahead to when in-person meetings will be possible again in the coming months. Even before the pandemic erupted, members already were asking for virtual options due to cost and environmental concerns associated with activities like flying, Fienberg said. Journalists have been able to attend virtual press conferences for many years now, and Fienberg said the pandemic has caused even more types of attendees to strongly consider the online option.

“I think it’s inevitable that the meeting of the future will be hybrid,” he said. “We just have to figure out how to make it work financially.”

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Some Black Holes May Actually Be Secret Wormholes – Popular Mechanics

This is deep.

Some scientists believe black holes aren’t all the same — and that some are really wormholes. To find out, we’ll need a way to tell the difference with certainty.

In a new paper, Russian scientists posit that the right blast of gamma radiation could reveal wormholes in black hole disguise.

How would a black hole wormhole work? The answer is actually relatively simple, and it also reveals why such a wormhole would have a detectable physical “tell.” Space’s Charles Q. Choi explains:

“Any matter falling into a mouth of a supermassive wormhole would likely travel at extraordinarily high speeds due to its powerful gravitational fields. The scientists modeled the consequences of matter flowing through both mouths of a wormhole to where these mouths meet, the wormhole’s “throat.” The result of such collisions are spheres of plasma expanding out both mouths of the wormhole at nearly the speed of light, the researchers said.”

This “outburst,” in the literal sense, is what scientists can look for. “The spheres of plasma from wormholes can reach temperatures of about 18 trillion degrees Fahrenheit (10 trillion degrees Celsius),” Choi writes. “At such heat, the plasma would produce gamma rays with energies of 68 million electronvolts.”

This radiation signature is distinct from even the most powerful and radiative known kinds of black holes. Because of that, the “fingerprint” could immediately tell scientists they were looking into a wormhole.

This part is important, because the theory of black holes as wormholes overlaps with one specific kind of black hole: the active galactic nucleus (AGN), which is gigantic and extraordinarily powerful.

AGNs give centers of galaxies their trademark brightness, hence the name, and scientists have argued about their true nature for a long time. “The underlying hypothesis of this work is that the active galactic nuclei are wormhole mouths rather than supermassive black holes,” the researchers explain.

AGNs aren’t well understood, with qualities of supermassive black holes mixed with extreme brightness. They’re broken into categories based on different factors, but the idea that they blast out a huge amount of radiation is what plays into this research. Their radiation signature is different enough from what would emerge from a true wormhole that scientists won’t mistake one for the other.

So how would such a test work? Think about looking at two lamps, where one has a “warm” compact fluorescent bulb and the other has a “natural” tone. You can immediately tell not just that they’re different, but likely what the difference indicates about what they both are. For cosmologists, the difference between wormholes and AGNs will be just as immediately clear. One of the authors of the paper told Space that he’s surprised this hasn’t been thought of before because of how simple it is.

In future research, if scientists can identify gamma radiation coming from a suspected galactic nucleus, these study findings mean they can hazard a guess that the object isn’t galactic nucleus at all. It could, in fact, be a wormhole. At the very least, it’s something new.

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Space discovery: FM radio signal found coming from Jupiter moon

SALT LAKE CITY (KTVX) – The Juno spacecraft orbiting Jupiter has discovered an FM radio signal coming from the moon Ganymede. The find is a first-time detection from the moon.

“It’s not E.T.,” said Patrick Wiggins, one of NASA’s Ambassadors to Utah. “It’s more of a natural function.”

Juno was traveling across the polar region of Jupiter — where magnetic field lines connect to Ganymede — when it crossed the radio source. Scientifically, it is called a “decametric radio emission.”

Here on Earth, we know it as Wi-Fi, and we use it every day.

According to Britannica.com, Jupiter’s radio emissions were discovered in 1955, and over the last 66 years, more and more discoveries have been made about how the signals work.

“A member of the Salt Lake Astronomical society once built an amateur radio telescope that could detect the electromagnetic radiation from Jupiter,” Wiggins said.

Juno’s mission is to study how the planet Jupiter formed and how it evolved.

“Juno will observe Jupiter’s gravity and magnetic fields, atmospheric dynamics and composition, and evolution,” according to NASA.

What caused the radio emissions from Jupiter’s moon? Electrons, not aliens, caused the signals.

The electrons oscillate at a lower rate than they spin, causing the electrons to amplify radio waves very rapidly. The process is called cyclotron maser instability (CMI). The electrons that generate the radio signal can also cause auroras in the far-ultraviolet spectrum, a phenomenon also observed by the camera on Juno.

The spacecraft saw the moon’s radio emission for only five seconds. It was flying by at 50 km per second — a screaming 111,847 mph.

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It’s really there! Kepler space telescope’s 2nd-ever exoplanet candidate finally confirmed

The Neptune-size KOI-5Ab does indeed exist

This artist’s illustration shows the exoplanet KOI-5Ab transiting across the face of a sunlike star, which is part of a triple-star system located 1,800 light-years away in the constellation Cygnus.

A newfound exoplanet is a real blast from the past.

Astronomers just confirmed the existence of KOI-5Ab, which was first flagged as a potential planet by NASA’s pioneering Kepler space telescope way back in 2009.

The elusive alien world was the second “candidate” ever identified by Kepler, which hunted for planets on two different missions from 2009 through 2018. Kepler used the “transit method,” spotting the telltale brightness dips caused when alien worlds crossed their host stars’ faces from the spacecraft’s perspective.

This work was incredibly productive. Nearly two-thirds of the roughly 4,300 known exoplanets were discovered by Kepler, and analyses of the telescope’s huge dataset continue to turn up new finds.

KOI-5Ab slipped through the cracks more than a decade ago partly as a result of that data deluge. The Kepler team spotted an apparent transit signal belonging to a roughly Neptune-size planet that whipped around a sunlike star every five Earth days. This star and the apparent planet lie about 1,800 light-years from Earth, in the constellation Cygnus.

But further investigation revealed that the parent star had a companion star, making analyses considerably more difficult. And there were many other candidates to vet.

So, KOI-5Ab “was quickly abandoned, mostly because it got complicated,” David Ciardi, chief scientist of NASA’s Exoplanet Science Institute, which is located at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, said during a news conference Monday (Jan. 11) at the 237th meeting of the American Astronomical Society (AAS).

Indeed, KOI-5Ab was even more complicated than researchers realized at the time. By 2014, Ciardi and other scientists had determined that the KOI-5 system actually harbors three stars. And it still wasn’t clear if KOI-5Ab actually existed, or if the 2009 signal was generated by one of the companion stars.

KOI-5Ab came back into the spotlight thanks to Kepler’s successor, NASA’s Transiting Exoplanet Survey Satellite (TESS), which launched in 2018. TESS also spotted a signal in the KOI-5 system, generated by a potential planet with an orbital period of five Earth days.

“I thought to myself, ‘I remember this target,'” Ciardi said in a statement.

So he took a hard look at all the information on the system — the transit observations by Kepler and TESS, as well as radial-velocity data gathered by ground-based instruments such as the Keck Observatory in Hawaii. (Radial-velocity measurements quantify how much an orbiting planet tugs on its parent star gravitationally. Such work can reveal the approximate mass of an exoplanet, whereas transit observations give a rough idea of its size.)

The KOI-5 star system consists of three stars, labeled A, B, and C in this diagram. Star A and B orbit each other every 30 years. Star C orbits stars A and B every 400 years. The system hosts one known planet, called KOI-5Ab, which was discovered and characterized using data from NASA’s Kepler and TESS (Transiting Exoplanet Survey Satellite) missions, as well as ground-based telescopes.

Taken together, the data confirmed that KOI-5Ab is indeed a planet, one that’s about half as massive as Saturn. The new research, which Ciardi detailed at the AAS meeting on Monday, also revealed other details of the KOI-5 system. For example, the main star that KOI-5Ab orbits (star A) has a close companion (star B); this duo orbits each other once every 30 Earth years. The third star in the system (star C) is much more distant, orbiting the A-B pair every 400 years.

In addition, KOI-5Ab’s orbital plane is misaligned with that of star B, suggesting that the star may have given the planet a gravitational boot sometime in the system’s history, researchers said. (Stars and their planets form from the same cloud of gas and dust, so their orbital planes generally match initially.)

KOI-5Ab is far from the first planet to be discovered in a multistar system. But such systems seem to host planets less frequently than do single-star solar systems like our own, for reasons that scientists don’t yet understand.

“Stellar companions may partially quench the process of planet formation,” Ciardi said. “We still have a lot of questions about how and when planets can form in multiple-star systems and how their properties compare to planets in single-star systems. By studying the KOI-5 system in more detail, perhaps we can gain insight into how the universe makes planets.”

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Rocky ‘super-Earth’ planet spotted orbiting one of the Milky Way’s oldest stars

The universe has been making rocky planets for a long, long time

Artist’s rendition of TOI-561, one of the oldest, most metal-poor planetary systems discovered yet in the Milky Way galaxy.

One of the oldest stars in the Milky Way galaxy hosts an unusually hot, rocky “super-Earth” planet, a new study reports.

Known as TOI-561b, this exoplanet is about 50% larger and three times more massive than Earth, researchers said. It whips around its host star in a very close orbit, taking less than 12 hours to complete one lap.

Given this close proximity, TOI-561b has an average surface temperature of over 3,140 degrees Fahrenheit (1,726 degrees Celsius), which is too hot to host any form of life as we know it, according to a statement from the University of California, Riverside.

The researchers also found that TOI-561b’s density is similar to that of Earth.

“This is surprising, because you’d expect the density to be higher,” study co-author Stephen Kane, a planetary astrophysicist from UC Riverside, said in the statement. “This is consistent with the notion that the planet is extremely old.”

Heavy elements such as iron and magnesium are manufactured by fusion reactions in the hearts of massive stars. The abundance of these elements has built up over time in the Milky Way and other galaxies, as more and more stars churn these materials out and expel them into space when they die in supernova explosions.

TOI-561b’s low density suggests that it has relatively few heavy elements and is therefore very old, forming perhaps 10 billion or so years ago, study lead author Lauren Weiss, a postdoctoral fellow at the University of Hawaii, said Monday (Jan. 11) during a presentation at the 237th meeting of the American Astronomical Society (AAS).

Indeed, the planet’s host star, TOI-561, is among a rare population of stars located in a region called the galactic thick disk. These stars are known to have distinctly fewer heavy elements than typical stars in the Milky Way.

“TOI-561b is one of the oldest rocky planets yet discovered,” Weiss said in the UC-Riverside statement. “Its existence shows that the universe has been forming rocky planets almost since its inception 14 billion years ago.”

Weiss and her colleagues discovered and characterized TOI-561b by studying observations made by NASA’s Transiting Exoplanet Survey Satellite (TESS) and the W.M. Keck Observatory in Hawaii. (TOI stands for “TESS Object of Interest.”)

The system lies about 280 light-years from Earth and harbors two other known planets in addition to TOI-561b. But these two other planets are too big, and not dense enough, to be rocky, unlike TOI-561b.

“Though this particular planet is unlikely to be inhabited today, it may be a harbinger of many rocky worlds yet to be discovered around our galaxy’s oldest stars,” Kane said in the statement.

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Scientists are getting closer in race to find gravitational wave background and dark matter

Researchers used pulsars shown in the inset to calculate dark matter’s affect on how stars move within the Milky Way.

Astronomers may be getting closer to discovering as-yet hidden cosmic secrets, such as the nature of dark matter and the presence of widespread distortions in space-time, researchers reported at the 237th American Astronomical Society meeting, held virtually this week.

The existence of dark matter, an the invisible substance thought to make up more than four-fifths of all matter in the universe, may help explain a variety of cosmic puzzles, such as how galaxies can spin as fast as they do without getting ripped apart. However, much about the nature of dark matter — and even whether it exists at all — remains unknown.

To help pinpoint dark matter’s properties, researchers sought to directly measure the gravitational effects that dark matter should have on the speed at which stars are moving in the Milky Way. They focused on galactic lighthouses known as pulsars, or spinning neutron stars that emit twin beams of radio waves from their magnetic poles as they rotate. (Neutron stars are the remains of large stars that perished in catastrophic explosions known as supernovas.)

“It is a very, very small number we are trying to measure,” study lead author Sukanya Chakrabarti, an astrophysicist at the Rochester Institute of Technology in New York, said during a news conference held on Monday (Jan. 11). “In terms of change in velocity, it’s just a few centimeters per second, or roughly the speed of a crawling baby, and not a very fast baby at that.”

Pulsars spin at very steady rates, so they can serve as precise clocks. By monitoring tiny variations in the spin of 14 pulsars, the researchers could estimate the speeds at which these pulsars are moving and thus deduce the gravitational force that dark matter is exerting on them.

The scientists found that across the galaxy, the average amount of dark matter may be slightly lower than previous estimates. The researchers also calculated the amount of dark matter contained within the volume of the Earth is just 1.63 lbs. (740 grams), Chakrabarti said. These findings in turn can help current experiments seeking to directly detect dark matter “try and understand the nature of dark matter particles,” she added. For instance, this might affect how often one might expect such particles to interact with detectors.

In addition, scientists are now analyzing an unusually high number of gamma rays from the center of the Milky Way to see if they might come from annihilating dark matter particles. Previous research suggested dark matter could be made of new kinds of particle, ones that annihilate when they come in contact with each other, generating high-energy gamma rays.

Based on 11 years of data from NASA’s Fermi Gamma-Ray Space Telescope, “we can say what are good candidates for dark matter,” study lead author Mattia di Mauro, an astrophysicist at the National Institute for Nuclear Physics in Torino, Italy, said during the same news conference. These include weakly interacting massive particles, or WIMPS, hypothetical elementary particles that only barely interact with ordinary matter except through their gravitational pull.

“In the future, the Large Hadron Collider or other particle physics detectors could test these specific candidates,” he added.

The gravitational background

Researchers at the premiere astronomy conference also reported finding the first possible hints of a mysterious new kind of gravitational wave, cosmic ripples that warp the fabric of space and time itself.

Scientists reported the first-ever direct detection of gravitational waves in 2016 using the Laser Interferometer Gravitational-Wave Observatory (LIGO), a discovery that earned the 2017 Nobel Prize in Physics. The space-time distortions those researchers saw were created when two black holes collided with each other about 130 million light-years from Earth. Since then, LIGO has observed dozens more such signals.

But the gravitational waves that LIGO are best at detecting are the most powerful ones, loud outbursts released when extraordinarily massive objects collide with one another. Researchers now also want to detect gravitational waves that are more like the background noise of small talk at a crowded party.

In theory, merging galaxies and other cosmic events should generate such a “gravitational wave background.” Detecting this steady hum could shed light on mysteries such as how galaxies have grown over time.

However, these waves are huge, posing a major challenge for detecting this gravitational wave background. Whereas existing gravitational-wave observatories on Earth are designed to search for gravitational waves on the order of seconds long, ripples from the gravitational wave background are years or even decades long.

Now researchers say they may have detected a strong signal of the gravitational wave background using a U.S. and Canadian project called the North American Nanohertz Observatory for Gravitational Waves (NANOGrav).

“We’re seeing incredibly significant evidence for this signal,” study lead author Joseph Simon, an astrophysicist at the University of Colorado Boulder, said during the AAS press conference. “Unfortunately, we can’t quite say what it is yet.”

NANOGrav uses telescopes on the ground to monitor dozens of pulsars. Gravitational waves can alter the steady blinking pattern of light from pulsars, squeezing and expanding the distances these rays travel through space.

“As these waves pass us, the Earth gets pushed around very slightly,” Simon said. “As Earth is pushed closer to pulsars in one part of the sky, those pulsars’ pulses will appear a little bit sooner than expected, and pulses from pulsars in the other part of the sky appear to come a bit later.”

Analyzing this pulsar light could therefore help scientists detect signs of the gravitational wave background.

“By monitoring signals from a large number of these pulsars, we created a galaxy-size gravitational-wave detector within our own Milky Way,” Simon said.

To find these subtle hints, NANOGrav scientists have attempted to observe as many pulsars as they can for as long as possible. So far, they have observed 45 pulsars for at least three years, and in some cases, for more than a dozen years.

“These pulsars are spinning about as fast as your kitchen blender,” Simon said in a statement. “And we’re looking at deviations in their timing of just a few hundred nanoseconds.”

Now the researchers said they have detected potential evidence of a common process distorting the light from many of the pulsars. As of yet, they cannot verify whether this signal is evidence for the gravitational wave background, “but we also don’t have evidence against it,” Simon said.

The scientists caution they still need to look at more pulsars and monitor them for longer time periods to confirm whether the gravitational background is the cause.

If the researchers can verify they have detected the gravitational wave background, they next want to pinpoint what causes these waves and what such signals can tell scientists about the universe.

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Astronomers spot the fastest spinning magnetar ever seen

It might be the youngest ever, too

Far-off in the Milky Way galaxy, 21,000 light-years from Earth, astronomers have spotted the fastest-spinning magnetar (and possibly youngest, too) ever seen. And that’s just the start of what makes this star strange.

Magnetars are a unique type of neutron stars, which are the collapsed cores of supergiant stars that died in supernova events. What sets magnetars apart from other neutron stars is that they possess extremely powerful magnetic fields — he most powerful ones in the known universe, in fact. They can also explode without warning and are fairly difficult to spot. In fact, before this object was discovered, there were only 30 known magnetars, compared to the thousands (approximately 3,000) known neutron stars.

Now, scientists studying the skies with NASA’s Chandra X-ray Observatory — a space telescope that looks out at black holes, supernovas and more — think that a newly discovered magnetar known as J1818.0-1607 could be the fastest-spinning and possibly also the youngest magnetar known, according to a statement. They also found a myriad of other odd things that make this object truly unique.

Magnetar J1818.0-1607, which lies 21,000 light-years away from Earth in the Milky Way galaxy.

Astronomers first spotted this magnetar on March 12, 2020 with NASA’s Neil Gehrels Swift Telescope. Later on, Harsha Blumer, an astronomer at West Virginia University, and Samar Safi-Harb, a physics professor at the University of Manitoba in Canada, observed the magnetar using Chandra, and they noticed a couple of peculiar things that made the magnetar stand out.

One of the first things that seemed intriguing about this particular object was how young it appeared. The team estimated that the magnetar is about 500 years old, which, if true, would make it the youngest discovered yet. They determined the object’s age by measuring how quickly the rotation rate of the magnetar is slowing down (it spins slower over time) while assuming that the object started out spinning much faster.

The second thing that really stood out to the team was just how fast the object was spinning, as it seemed to be rotating once fully every 1.4 seconds (which is really, really fast).

Other astronomers have taken a look at J1818.0-1607 as well, observing the magnetar using radio telescopes like the National Science Foundation’s Karl Jansky Very Large Array (VLA) and have found that it’s emitting radio waves, a quality it shares with objects known as “rotation powered pulsars.” These are a type of neutron star that emits radiation that we on Earth detect as “pulses” of radio wave emissions.

In this up-close composite image, you can see magnetar J1818.0-1607 in purple. Scientists think that this object could be the fastest-spinning and possibly even youngest magnetar ever found.

Blumer and Safi-Harb also found that the magnetar isn’t converting spinning energy from its rotations into X-ray emissions as efficiently as expected for a magnetar. In fact, the object is converting this energy at a rate most common with rotation-powered pulsars, another interesting commonality between the two objects.

The last odd thing that the pair of researchers found about this young, fast star was that, while most magnetars around this age would have left behind a debris field of material leftover from the supernova that created the object, the researchers only found possible evidence of a supernova remnant with J1818.0-1607, and this debris was pretty far from the object.

By their estimations, in order for the debris field to have traveled that far away from the magnetar, the object would’ve needed to have traveled at speeds faster than ever seen with a neutron star.

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Sean Robinson wrote:

the main star that KOI-5Ab orbits (star A) has a close companion (star B); this duo orbits each other once every 30 Earth years. The third star in the system (star C) is much more distant, orbiting the A-B pair every 400 years.

I am most likely missing something but I did not think stars have orbits. Our sun is stationary, isn’t it?

Our sun is orbiting the centre of the milky way galaxy at a ridiculously fast rate. All stars do.

In addition, most stars are in multiple-star systems (the sun is in the minority of being a solo star). In this case, the stars orbit around each other, as well as the whole group revolving around the galaxy.

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Plus. all the planets don’t rotate around the centre of the sun, they all orbit the barycenter of the respective orbit systems.

Or some complex shit like that.

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The most distant quasar ever found is hiding a seriously supermassive black hole

J0313-1806 is a cosmic treasure

In a breakthrough discovery, scientists have found the most distant quasar yet known — and it’s home to a seriously supermassive black hole.

Astronomers led by researchers at the University of Arizona spotted the brilliant quasar about 13.03 billion light-years from Earth. Quasars are among the brightest objects in the universe, quasars are luminous, active galactic nuclei powered by supermassive black holes that are actively feeding on nearby material.

When this material gets sucked in, quasars release ultra-bright beams of electromagnetic radiation. Scientists suspect that these glowing, ultramassive objects could actually be an evolutionary stage for some galaxies. In fact, scientists estimate that, on average, this particular quasar’s black hole ingests an amount of mass equivalent to 25 suns every year.

This quasar, called J0313-1806, can be dated back to just 670 million years after the Big Bang (the universe at this time was a mere 5% of its current age), making it the most distant and earliest quasar ever found. This quasar also hosts a supermassive black hole that has a mass equal to 1.6 billion of our suns.

This artistic visualization shows J0313-1806, the most distant (and therefore earliest) quasar ever found.

A record-breaking quasar

While this newfound quasar is astoundingly old and far away, the team’s observations also showed evidence that there is a wind of super-heated gas flowing from around the galaxy’s supermassive black hole, with this gas traveling at one fifth the speed of light, according to a statement. If this strong quasar-driven wind coming from the most distant quasar ever spotted wasn’t interesting enough, the team also found extremely active star formation activity in the galaxy holding the quasar.

J0313-1806 is estimated to create about 200 solar masses every single year, compared to our Milky Way’s one solar mass per year, according to the statement.

“This is a relatively high star formation rate, similar to that observed in other quasars of similar age, and it tells us the host galaxy is growing very fast,” lead author Feige Wang, a Hubble Fellow at the University of Arizona’s Steward Observatory, said in the same statement.

Quasar investigation

Now, because of their close relationship, scientists think that, by studying quasars, they can learn more about how the objects came to be and how supermassive black holes really behave.

While this quasaris only 20 million light-years farther from Earth than the one that last held the title of “farthest quasar,” the new record-holder’s supermassive black hole is about twice as heavy as that of its predecessor. This detail could change how scientists understand the relationship between these supermassive, super-bright cosmic objects.

“This is the earliest evidence of how a supermassive black hole is affecting its host galaxy around it,” Wang said. “From observations of less distant galaxies, we know that this has to happen, but we have never seen it happening so early in the universe.”

How do you make a supermassive black hole

Quasars like J0313-1806 that already accumulated such immensely massive black holes in such a short time in the early universe have puzzled scientists for years. While black holes can be created when stars explode in supernova and collapse and smaller black holes can merge, eventually building up mass, these ultra-massive early-universe quasars remain mysterious. How did they get so massive so quickly?

With this “new” quasar to study, this team is narrowing in on how such a supermassive black hole could have gained such mass and formed in such a short amount of time. The quasar’s black hole is too massive to be explained by some former theories. In fact, the team thinks that, even if the black hole formed as early as 100 million years after the Big Bang and grew as fast as possible, it would still only be 10,000 times as massive as our sun — and it’s 1.6 billion times as massive.

“This tells you that no matter what you do, the seed of this black hole must have formed by a different mechanism,” co-author Xiaohui Fan, a professor and associate head of the Department of Astronomy at the University of Arizona. “In this case, one that involves vast quantities of primordial, cold hydrogen gas directly collapsing into a seed black hole … “In order for the black hole to have grown to the size we see with J0313-1806, it would have to have started out with a seed black hole of at least 10,000 solar masses, and that would only be possible in the direct collapse scenario.”

The team hopes to find more quasars “born” around this same time in the early universe to help them explore further and better understand how such massive, powerful objects came to be.

“Our quasar survey covers a very wide field, allowing us to scan almost half of the sky,” co-author Jinyi Yang, a Peter A. Strittmatter Fellow at the Steward Observatory, said in the same statement. “We have selected more candidates on which we will follow up with more detailed observations.”

Yang added that future observations with a space-based telescope like NASA’s James Webb Space Telescope could propel such research even further.

“With ground-based telescopes, we can only see a point source,” Wang said. “Future observations could make it possible to resolve the quasar in more detail, show the structure of its outflow and how far the wind extends into its galaxy, and that would give us a much better idea of its evolutionary stage.”

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Gas giant exoplanet with weirdly long orbit may bear clues about our solar system

An artist’s rendering of a 10-million-year-old star system with a gas-giant planet like Jupiter.

Scientists have managed to measure both the size and orbit of a gas giant exoplanet nearly 1,300 light-years away from Earth. Dubbed GOT ‘EM-1b, which stands for Giant Outer Transiting Exoplanet Mass, the planet is roughly five times the mass of Jupiter.

Usually scientists struggle to measure the size of giant gas planets, like Jupiter and Saturn, because they’re far away from the stars they orbit. Yet, this planet showed up in what researchers call our “solar neighborhood” in 2010, when NASA’s Kepler space telescope first discovered the object. Astronomers then noticed periodic decreases in the brightness of a nearby star, called Kepler-1514, which clued the researchers in to the possibility of orbiting planets.

The research team at the University of California, Riverside discovered that the planet, officially named Kepler-1514b after its parent star, has an unusually long orbit of 218 days. “Taking 218 days to orbit a star is an order of magnitude longer than most giant exoplanets we’ve measured,” Paul Dalba, the astronomer who led the research, said in a UC Riverside statement provided to Space.com. Of the thousands of planets Kepler has discovered, only a few dozen have had orbits of 200 days or longer.

It’s possible that learning more about GOT ‘EM-1b and giant planets like it could tell us more about the solar system. “This planet is like a stepping stone between the giant planets of our own solar system, which are very far from our sun, and other gas giants that are much closer to their stars,” Dalba said.

The discovery of a giant planet that hasn’t moved closer to its star over time will serve as an analog to the gas giants in our solar system and tell us about how normal our solar system is in its stability and development. Astronomers believe that Jupiter might be protecting Earth from other objects in space that might otherwise impact our planet, giving our “blue marble” relative stability.

Unfortunately, it’s difficult to find analogs to Jupiter and Saturn, so scientists are excited to learn more about GOT ‘EM-1b.

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Triple-star system’s strange antics entrance scientists digging through 125 years of data

“It was as if somebody had just created a telescope that was a time machine.”

A view of HS Hydra, in the center, captured by the Digitized Sky Survey.

Scientists have combined modern spacecraft data with vintage observations to piece together a 125-year-long story of the antics of a nearby triple-star system dubbed HS Hydra — and predict its future.

When the first of those observations were made, in 1893, HS Hydra was just another star twinkling in the heavens. Now, it’s a strange, dynamic system — and one that may have a few more surprises in store.

Astronomers may soon unearth those surprises, thanks to NASA’s Transiting Exoplanet Survey Satellite (TESS). And scientists think this spacecraft, better known for discovering alien worlds, could unveil similar mysteries in bright but seemingly humdrum binary star systems, according to research presented at the 237th meeting of the American Astronomical Society, held virtually this week due to the coronavirus pandemic.

“It’s just been one of those topics that we knew was going to be really exciting, that TESS was going to be really powerful for,” James Davenport, an astronomer at the University of Washington, told Space.com of bright, binary star systems. But it isn’t the first time astronomers have turned to these objects, he said. “This was like your grandfather’s astrophysics or whatever; binary stars were really hot 60 or 70 years ago because that was the really dynamic thing they could study.”

TESS isn’t technically an astrophysics mission: The spacecraft was designed to spot exoplanets by looking for small, regular dips in the light of a bright star — the shadows of an alien world coming between its star and the spacecraft.

But a dip doesn’t necessarily mean a planet. Sometimes, for instance, it means that the star is actually two stars, which are circling each other edge-on to Earth. And when the stars overlap in the spacecraft’s view, the light dips: ta-da, a binary star system in an exoplanet mission’s data.

So Davenport read up on binary stars, tracking down an old article for amateur astronomers that profiled intriguing binary stars. “It was one of those great moments, like, … ‘I bet TESS observed a bunch of these,'” he said. “It was one of those late-night, ‘Gosh, what if I just dig into this for an hour’ — and then it was two in the morning and I was up too late.”

Of these binaries, HS Hydra was the system that particularly caught his attention. That’s because in 2012, astronomers took a new look at the system, which is about 342 light-years away from Earth, and realized it wasn’t just two stars circling each other every day and a half or so: There was a third, more distant and much smaller star tugging at the main pair. This companion was slowly pulling their dance out of humans’ edge-on view, the researchers realized.

Given the observations, the scientists predicted that the eclipses as seen from Earth would end around 2022. And Davenport was looking at 2019 TESS data that still showed small eclipses. “The prediction that they should end in 2022 wasn’t obviously wrong,” he said.

Using the new TESS data, Davenport and his student co-authors have predicted that HS Hydra’s eclipses will end not in 2022, but early this year, perhaps in February — just in time for the spacecraft to check back in on the system. And whenever the two main stars do stop eclipsing, TESS will still be able to see their interactions as each stretches the other into a slight teardrop shape.

HS Hydra through the ages

But as excited as Davenport is about TESS, he said that the most compelling aspect of the HS Hydra research is being able to pull in data from more than a century before scientists even dreamed up the mission. The earliest observations the researchers tracked down are from 1893, when the Wright brothers were still focused on selling bicycles. In these records, the stars are immortalized on glass plates in an early form of photography.

“Astronomers would have to ride on the telescope in the dark and change the glass plates out at night,” Davenport said. “It was a wild time to be an observational astronomer, which, I guess thankfully, I was not around for.”

But those plates are still around, many of them put online by the Digital Access to a Sky Century at Harvard project, where archivists have also calibrated the data and included logbook notes from the original observers. Davenport and his colleagues ignored plates that seemed worse for wear and still had more than 1,000 observations ready to analyze.

“It was as if somebody had just created a telescope that was a time machine,” he said. “We just went and downloaded the data in the same way that we would download the data from a modern space-based archive.”

With that time machine, Davenport and his colleagues can paint a 125-year narrative with peculiar echoes of humans’ history with space.

A digital image of a glass plate that captured astronomical observations in 1945.

For decades, as humans developed first airplanes and then rockets, HS Hydra was just a star. In 1959, its eclipse was at its most dramatic as seen from Earth, and scientists realized its binary nature five years later.

“Right at the dawn of the space era, right after Sputnik has launched and we’re getting ready to go to the moon and all these things are getting ready to happen, that’s when the system is at its maximum,” Davenport said.

Over the next decades, the unseen third star in the system gradually spun the binary, tilting the eclipse so that it became more difficult to detect. But scientists have kept up. “As it’s gotten harder and harder to study, our tools have gotten better and better,” Davenport said.

But their interest? Maybe not so much. “It was never an exciting system,” he said. By the early 2000s, scientists were bored of it. “They thought, eh, that’s just another eclipsing binary. There’s nothing particularly special about it.”

Then scientists realized the impact of the system’s third star, a special characteristic indeed, and in 2018, TESS began work. “Now we’re at this inflection point, where we have this new survey that is going to, I think, revolutionize studies of binary stars … and this system is now sort of bowing out,” Davenport said. The scientists’ new calculations predict that HS Hydra will begin eclipsing again around 2195.

But there’s always a chance scientists haven’t actually solved the puzzle of HS Hydra, he said, and that the system will continue to surprise astronomers as the data set becomes still longer. “We’ve only seen it for 100 years,” Davenport said. “It might not be a straight line through time: It might slowly curve or it might wiggle again, if there’s a fourth star out there dancing with them.”

An image captured by NASA’s Transiting Exoplanet Survey Satellite (TESS) shows stars scattered across the northern sky around the constellation Cygnus.

Because what is an envy-inducing time frame for an observational astronomer is just a snap for an astronomical object. And that means that scientists would do well to look both backward and forward, Davenport said — to both salvage the field’s earliest data and think carefully about how to ensure today’s observations remain accessible.

“The images we take now will be these photographic plates a century from now; somebody will look back very quaintly and say, ‘Oh, they had this cute little telescope they called TESS,'” he said. “Someday, they’ll look back on this data and it will be the very rough, noisy building block of some other cool project.”

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Pictures from space! Our image of the day

Spotting a supernova

Jan. 15, 2021: The Hubble Space Telescope spotted a growing, gaseous supernova remnant, known as 1E 0102.2-7219, from a supernova explosion that occurred 1,700 years ago during the fall of the Roman Empire. The star that exploded in the event was from the Small Magellanic Cloud, a satellite galaxy to our own Milky Way Galaxy located about 200,000 light-years away.

At the time of the supernova event, people living in Earth’s southern hemisphere would have been able to see the light coming from this blast, though there are no known records of the event from humans on Earth.

Watching the weather from space

Jan. 13, 2021: In this view from space captured by the Copernicus Sentinel-3 satellite, you can see a heavy blanket of snowfall over much of Spain. The image, snapped at 5:40 a.m. EST (1040 GMT) on Jan. 12, shows most of the country covered in snow following storm Filomena, which brought the heaviest snowfall that Spain has seen for 50 years.

Copernicus Sentinel-3 is a two-satellite mission that, with a variety of instruments, observes and monitors Earth’s surface from above.

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