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      The Windchime experiment could use gravity to hunt for dark matter ‘wind’

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      The secret to directly detecting dark matter might be blowin’ in the wind.

      The mysterious substance continues to elude scientists even though it outweighs visible matter in the universe by about 8 to 1. All laboratory attempts to directly detect dark matter — seen only indirectly by the effect its gravity has on the motions of stars and galaxies — have gone unfulfilled.

      Those attempts have relied on the hope that dark matter has at least some other interaction with ordinary matter in addition to gravity (SN: 10/25/16). But a proposed experiment called Windchime, though decades from being realized, will try something new: It will search for dark matter using the only force it is guaranteed to feel — gravity.

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      “The core idea is extremely simple,” says theoretical physicist Daniel Carney, who described the scheme in May at a meeting of the American Physical Society’s Division of Atomic Molecular and Optical Physics in Orlando, Fla. Like a wind chime on a porch rattling in a breeze, the Windchime detector would try to sense a dark matter “wind” blowing past Earth as the solar system whips around the galaxy.  

      If the Milky Way is mostly a cloud of dark matter, as astronomical measurements suggest, then we should be sailing through it at about 200 kilometers per second. This creates a dark matter wind, for the same reason you feel a wind when you stick your hand out the window of a moving car.

      The Windchime detector is based on the notion that a collection of pendulums will swing in a breeze. In the case of backyard wind chimes, it might be metal rods or dangling bells that jingle in moving air. For the dark matter detector, the pendulums are arrays of minute, ultrasensitive detectors that will be jostled by the gravitational forces they feel from passing bits of dark matter. Instead of air molecules bouncing off metal chimes, the gravitational attraction of the particles that make up the dark matter wind would cause distinctive ripples as it blows through a billion or so sensors in a box measuring about a meter per side.

      Within the Windchime detector (illustrated as an array of small pendulums), a passing dark matter particle (red dot) would gravitationally tug on sensors (blue squares) and cause a detectable ripple, much like wind blowing through a backyard wind chime.D. Carney et al/Physical Review D 2020

      While it may seem logical to search for dark matter using gravity, no one has tried it in the nearly 40 years that scientists have been pursuing dark matter in the lab. That’s because gravity is, comparatively, a very weak force and difficult to isolate in experiments. 

      “You’re looking for dark matter to [cause] a gravitational signal in the sensor,” says Carney, of Lawrence Berkeley National Laboratory in California. “And you just ask . . . could I possibly see this gravitational signal? When you first make the estimate, the answer is no. It’s actually going to be infeasibly difficult.”

      That didn’t stop Carney and a small group of colleagues from exploring the idea anyway in 2020. “Thirty years ago, this would have been totally nuts to propose,” he says. “It’s still kind of nuts, but it’s like borderline insanity.”

      The Windchime Project collaboration has since grown to include 20 physicists. They have a prototype Windchime built of commercial accelerometers and are using it to develop the software and analysis that will lead to the final version of the detector, but it’s a far cry from the ultimate design. Carney estimates that it could take another few decades to develop sensors good enough to measure gravity even from heavy dark matter.

      Carney bases the timeline on the development of the Laser Interferometer Gravitational-Wave Observatory, or LIGO, which was designed to look for gravitational ripples coming from black holes colliding (SN: 2/11/16). When LIGO was first conceived, he says, it was clear that the technology would need to be improved by a hundred million times. Decades of development resulted in an observatory that views the sky in gravitational waves. With Windchime, “we’re in the exact same boat,” he says.

      Even in its final form, Windchime will be sensitive only to dark matter bits that are roughly the mass of a fine speck of dust. That’s enormous on the spectrum of known particles — more than a million trillion times the mass of a proton.

      “There is a variety of very interesting dark matter candidates at [that scale] that are definitely worth looking for … including primordial black holes from the early universe,” says Katherine Freese, a physicist at the University of Michigan in Ann Arbor who is not part of the Windchime collaboration. Black holes slowly evaporate, leaking mass back into space, she notes, which could leave many relics formed shortly after the Big Bang at the mass Windchime could detect.

      But if it never detects anything at all, the experiment still stands out from other dark matter detection schemes, says Dan Hooper, a physicist at Fermilab in Batavia, Ill., also not affiliated with the project. That’s because it would be the first experiment that could entirely rule out some types of dark matter.

      Even if the experiment turns up nothing, Hooper says, “the amazing thing about [Windchime] … is that, independent of anything else you know about dark matter particles, they aren’t in this mass range.” With existing experiments, a failure to detect anything could instead be due to flawed guesses about the forces that affect dark matter (SN: 7/7/22).  

      Windchime will be the only experiment yet imagined where seeing nothing would definitively tell researchers what dark matter isn’t. With a little luck, though, it could uncover a wind of tiny black holes, or even more exotic dark matter bits, blowing past as we careen around the Milky Way. More

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      A new James Webb telescope image reveals a galactic collision’s aftermath

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      It’s not easy being ringed. A newly released image from the James Webb Space Telescope, or JWST, shows the Cartwheel Galaxy still reeling from a run-in with a smaller galaxy 400 million years ago.

      The Cartwheel Galaxy, so called because of its bright inner ring and colorful outer ring, lies about 500 million light-years from Earth. Astronomers think it used to be a large spiral like the Milky Way, until a smaller galaxy smashed through it. In earlier observations with other telescopes, the space between the rings appeared shrouded in dust.

      Now, JWST’s infrared cameras have peered through the dust and found previously unseen stars and structure (SN: 7/11/22). The new image shows sites of intense star formation throughout the galaxy that were triggered by the collision’s aftereffects. Some of those new stars are forming in spokelike patterns between the central ring and the outer ring, a process that is not well understood.

      When the Hubble Space Telescope observed the Cartwheel Galaxy in visible light (left), the spokes between the galaxy’s bright rings were barely visible wisps. JWST’s infrared eyes brought them into vivid focus (right). Near-infrared light (blue, orange and yellow) traces newly forming stars; mid-infrared light (red) highlights the galaxy’s chemistry.Left: Hubble/NASA and ESA; Right: NASA, ESA, CSA, STScI and Webb ERO Production Team

      Ring galaxies are rare, and galaxies with two rings are even more unusual. That strange shape means that the long-ago collision set up multiple waves of gas rippling back and forth in the galaxy left behind. It’s like if you drop a pebble in the bathtub, says JWST project scientist Klaus Pontoppidan of the Space Telescope Science Institute in Baltimore. “First you get this ring, then it hits the walls of your bathtub and reflects back, and you get a more complicated structure.”

      The effect probably means that the Cartwheel Galaxy has a long road to recovery ahead — and astronomers don’t know what it will look like in the end.

      As for the smaller galaxy that caused all this mayhem, it didn’t stick around to get its picture taken. “It’s gone off on its merry way,” Pontoppidan says. More

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      Two black holes merged despite being born far apart in space

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      Signals buried deep in data from gravitational wave observatories imply a collision of two black holes that were clearly born in different places.

      Almost all the spacetime ripples that experiments like the Laser Interferometer Gravitational-Wave Observatory, or LIGO, see come from collisions among black holes and neutron stars that are probably close family members (SN: 1/21/21). They were once pairs of stars born at the same time and in the same place, eventually collapsing to form orbiting black holes or neutron stars in old age.

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      Now, a newly noted marriage of black holes, found in existing data from U.S.–based LIGO and its sister observatory Virgo in Italy, seems to be of an unrelated pair. Evidence for this stems from how they were spinning as they merged into one, researchers report in a paper in press at Physical Review D. Black holes that are born in the same place tend to have their spins aligned, like a pair of toy tops spinning on a table, as they orbit each other. But the pair in this case have no correlation between their respective spins and orbits, implying that they were born in different places.

      “This is telling us we’ve finally found a pair of black holes that must come from the non-grow-old-and-die-together channel,” says Seth Olsen, a physicist at Princeton University.

      Previous events that have turned up in gravitational wave observations show back holes merging that aren’t perfectly aligned, but most are close enough to strongly imply family connections. The new detection, which Olsen and colleagues found by sifting through data that the LIGO-Virgo collaboration released to the public, is different. One of the black holes is effectively spinning upside down.

      That can’t easily happen unless the two black holes come from separate places. They probably met late in their stellar lives, unlike the black hole littermates that seem to make up the bulk of gravitational wave observations.

      In addition to the merger between unrelated black holes, Olsen and his collaborators identified nine other black hole mergers that had slipped through the prior LIGO-Virgo studies (SN: 8/4/21).

      “This is actually the nice thing about this type of analysis,” says LIGO scientific collaboration spokesperson Patrick Brady, a physicist at the University of Wisconsin–Milwaukee who was not affiliated with the new study. “We deliver the data in a format that can be used by other people and then [they] will have access to try out new techniques.”

      To compile so many new signals in data that had already been gone over by other researchers, Olsen’s group lowered the analytical bar a little.

      “Out of the 10 new ones,” Olsen says, “there are about three of them, statistically, that probably come from noise,” rather than being definitive black hole merger detections. Assuming that the merger of black holes strangers is not among the errant signals, it almost certainly tells a tale of black hole histories distinct from the others seen so far.

      “It would be [extremely] unlikely for this to come from two black holes that have been together for their whole lifespan,” Olsen says. “This must have been a capture. That’s cool because we’re finally able to start probing that region of the [black hole] population.”

      Brady notes that “we don’t understand the theory [of black hole mergers] well enough to be able to confidently predict all of these types of things.” But the recent study may point to new and interesting opportunities in gravitational wave astronomy. “Let’s follow this clue to see if it really is reflecting something rare,” he says. “Or if not, well, we’ll learn other things.” More

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      Astronauts might be able to use asteroid soil to grow crops

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      Astronauts might one day dine on salad grown in asteroid soil.

      Romaine lettuce, chili pepper and pink radish plants all grew in mixtures of peat moss and faux asteroid soil, researchers report in the July Planetary Science Journal.  

      Scientists have previously grown crops in lunar dirt (SN: 5/23/22). But the new study focuses on “carbonaceous chondrite meteorites, known to be rich in volatile sources — water especially,” says astroecologist Sherry Fieber-Beyer of the University of North Dakota in Grand Forks. These meteorites, and their parent asteroids, are also rich in nitrogen, potassium and phosphorus — key agricultural nutrients. Pulverizing these types of asteroids, perhaps as part of space mining efforts, could potentially provide a ready supply of farming material in space.

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      Fieber-Beyer purchased a material that mimics the space rocks’ composition and gave it to her graduate student Steven Russell. “I said, ‘All right, grow me some plants.’”

      Russell, now an astrobiologist at the University of Wisconsin–Madison, chose a type of radish, lettuce and chili pepper — all of which have grown aboard the International Space Station. He, Fieber-Beyer and their colleague Kathryn Yurkonis, also of the University of North Dakota, compared how the plants grew in only faux asteroid soil, only peat moss and various mixes of the two.

      Peat moss keeps soil loose and improves water retention. In all mixtures with peat moss, the plants grew. Faux asteroid soil on its own, however, compacted and couldn’t retain water, and so plants couldn’t grow.

      Next, Fieber-Beyer will try growing hairy vetch seeds in that faux asteroid dirt, let the plants decay and then mix the dead plant matter throughout the soil. That, she says, could ensure that the soil doesn’t compact. Plus, seeds weigh a lot less than peat moss, making them easier to carry to space to help with any future farming attempts. More

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      Amateur astronomers’ images of a rare double aurora may unlock its secrets

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      What happens when two different kinds of auroras get together? One spills the other’s secrets.

      Amateur astronomers have captured a strange combination of red and green auroras on camera, and physicists — who had never seen such a thing before — have now used these images to learn what may trigger the more mysterious part of the lightshow.

      Photographer Alan Dyer was in his backyard in Strathmore, Canada, when he saw the lights dancing overhead and started filming. “I knew I had something interesting,” says Dyer, who also writes about astronomy. What he didn’t know was that he had just made the most complete recording of this rare phenomenon.

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      At a glance, Dyer’s video looks like a celestial watermelon. The rind, a rippling green aurora, is well understood: It appears when the solar wind energizes protons trapped within Earth’s magnetic field, which then rain down and knock electrons and atoms around (SN: 12/10/03).  

      The swath of fruity magenta is more mysterious: Though scientists have known about these “stable auroral red arcs” for decades, there’s no widely accepted proof of how they form. One popular theory is that part of Earth’s magnetic field can heat up the atmosphere and, like proton rain, jostle particles.   

      But until now, researchers had never seen both of these red and green auroras side by side, says Toshi Nishimura, a space physicist at Boston University. “This strange combination,” he says, “was something beyond our expectations.”

      [embedded content]
      Alan Dyer’s footage of this rare double aurora, a time lapse captured over 33 minutes on October 12, 2021, is helping physicists tease out clues to what causes the red glow.

      Along with satellite observations, Dyer’s images and similar ones captured by other amateur astronomers in Canada and Finland show that the two phenomena are related, Nishimura’s team reports in the July JGR Space Physics. Thin rays in the red aurora are the smoking gun as to how. Those lines trace the paths of electrons as they fall along the Earth’s magnetic field. So just as proton rain triggers the green aurora, electron rain appears to trigger the red one, with the solar wind powering both at the same time. Since the electrons carry less energy than the protons, they make for a more reddish color. 

      But electron rain might not be the only way to produce these red glows, cautions Brian Harding, a space physicist at the University of California, Berkeley. Either way, he says, the results are exciting because they show what’s going on is more complicated than researchers thought.

      Those complications are important to understand. The auroras Dyer saw, though beautiful, are danger zones for radio communication and GPS systems (SN: 8/13/17). As Nishimura puts it: If you were driving under a subauroral red arc, your GPS might tell you to veer into a field.

      Until scientists better understand these red glows, they won’t be able to forecast space weather like they do normal weather, Harding explains. “You want to make sure that you can predict stuff like this,” he says.

      The new results would not have been possible without the citizen scientists who took the photos, Nishimura says. “This is a new way of doing research…. When they take more and more cool images, they find more and more things that we don’t know about.”

      According to Dyer, more photos are exactly what’s coming. “We can make a unique contribution to science,” he says.  After all, “you never know what’s going to appear.” More

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      The heaviest neutron star on record is 2.35 times the mass of the sun

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      A fast-spinning neutron star south of the constellation Leo is the most massive of its kind seen so far, according to new observations.

      The record-setting collapsed star, named PSR J0952-0607, weighs about 2.35 times as much as the sun, researchers report July 11 on arXiv.org. “That’s the heaviest well-measured neutron star that has been found to date,” says study coauthor Roger Romani, an astrophysicist at Stanford University.

      The previous record holder was a neutron star in the northern constellation Camelopardalis named PSR J0740+6620, which tipped the scales at about 2.08 times as massive as the sun. If a neutron star grows too massive, it collapses under its own weight and becomes a black hole. These measurements of hefty neutron stars are of interest because no one knows the exact mass boundary between neutron stars and black holes.

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      That dividing line drives the quest to find the most massive neutron stars and determine just how massive they can be, Romani says. “It’s defining the boundary between the visible things in the universe and the stuff that is forever hidden from us inside of a black hole,” he says. “A neutron star that’s on the hairy edge of becoming a black hole — just about heavy enough to collapse — has at its center the very densest material that we can access in the entire visible universe.”

      PSR J0952-0607 is in the constellation Sextans, just south of Leo. It resides 20,000 light-years from Earth, far above the galaxy’s plane in the Milky Way’s halo. The neutron star emits a pulse of radio waves toward us each time it spins, so astronomers also classify the object as a pulsar. First reported in 2017, this pulsar spins every 1.41 milliseconds, faster than all but one other pulsar.

      That’s why Romani and his colleagues chose to study it — the fast spin led them to suspect that the pulsar might be unusually heavy. That’s because another star orbits the pulsar, and just as water spilling over a water wheel spins it up, gas falling from that companion onto the pulsar could have sped up its rotation while also boosting its mass.

      Observing the companion, Romani and his colleagues found that it whips around the pulsar quickly — at about 380 kilometers per second. Using the companion’s speed and its orbital period of about six and a half hours, the team calculated the pulsar’s mass to be more than twice the mass of the sun. That’s a lot heavier than the typical neutron star, which is only about 1.4 times as massive as the sun.

      “It’s a terrific study,” says Emmanuel Fonseca, a radio astronomer at West Virginia University in Morgantown who measured the mass of the previous record holder but was not involved in the new work. “It helps nuclear physicists actually constrain the nature of matter within these extreme environments.” More

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      How James Webb Space Telescope data have already revealed surprises

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      Massimo Pascale wasn’t planning to study the galaxy cluster SMACS 0723. But as soon as he saw the cluster glittering in the first image from the James Webb Space Telescope, or JWST, he and his colleagues couldn’t help themselves.

      “We were like, we have to do something,” says Pascale, an astronomer at the University of California, Berkeley. “We can’t stop ourselves from analyzing this data. It was so exciting.”

      Pascale’s team is one of several groups of scientists who saw the first JWST images and immediately rolled up their sleeves. In the first few days after images and the data used to create them were made public, scientists have estimated the amount of mass the cluster contains, uncovered a violent incident in the cluster’s recent past and estimated the ages of the stars in galaxies far beyond the cluster itself.

      “We’ve been preparing for this for a long time. Myself, I’ve been preparing for years, and I’m not very old,” says Pascale, who is in his fourth year of graduate school.  JWST “is really going to define a new generation of astronomers and a new generation of science as a whole.”

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      Cluster collision

      When the image of SMACS 0723 was released in a White House briefing on July 11, most of the focus went to extremely distant galaxies in the background (SN: 7/11/22). But smack in the middle of the image is SMACS 0723 itself, a much closer cluster of galaxies about 4.6 billion light-years from Earth. Its mass bends light from even farther away, making more distant objects appear magnified, as if their light had traveled through the lens of another cosmic-sized telescope.

      The light from the most distant galaxy in this image started its journey to JWST about 13.3 billion years ago — “almost at the dawn of the universe,” says astrophysicist Guillaume Mahler of Durham University in England, who is already using the picture as his Zoom background.

      But the image can also fill in the history of the intervening galaxy cluster itself. “People sometimes forget about that — the galaxy cluster is also very important,” Pascale says.

      Pascale’s and Mahler’s teams each started by taking inventory of the distant galaxies that appear stretched and distorted in the image. The light from some of those galaxies is warped such that multiple images of the same galaxy appear in different places. Mapping those multiply imaged galaxies is a sensitive probe of the way mass is spread around the cluster. That, in turn, can reveal where the cluster contains dark matter, the invisible, mysterious substance that makes up the majority of the mass in the universe (SN: 9/10/20).

      Both teams found that SMACS 0723 is more elongated than it appeared in previous observations. They also found a faint glow, called intracluster light, inside the cluster from stars that don’t belong to any particular galaxy. Together, those features suggest that SMACS 0723 is still recovering from a relatively recent smash-up with another galaxy cluster, the teams report separately in a pair of papers submitted to arXiv.org on July 14.

      A galaxy cluster that has been sitting on its own for eons should have a rounder distribution of matter and intracluster light, rather than SMACS 0723’s oblong shape. The stars that emit the intracluster light were probably ripped from their home galaxies by gravitational forces during the collision.

      “Two separate clusters have merged together, and it looks to us as if it’s not totally settled yet,” Pascale says. “What we might be looking at is an ongoing merger.”

      Three examples of multiply imaged galaxies — marked with white, red and yellow arrows — popped out of this small region of the first JWST image. The gravity from a foreground galaxy cluster distorted the light from these galaxies, making them appear in at least two places at once.Reproduced from M. Pascale et al/arXiv.org 2022

      Far-flung galaxies

      Mapping out mass in the cluster is also essential to decoding the properties of the more distant galaxies in the background of the image, Mahler says. “You need to understand the cluster and its magnification power to understand what’s behind.”

      Some scientists are already investigating those distant galaxies in detail. The first JWST data include not just pretty pictures but also spectra, measurements of how much light an object emits at various wavelengths. Spectra allow scientists to determine how much a distant object’s light has been stretched — or redshifted — by the expansion of the universe, which is a proxy for its distance. Such data can also help reveal a galaxy’s composition and the ages of its stars.

      “The main thing that limits the study of star formation in galaxies is the quality of the data,” says astrophysicist Adam Carnall of the University of Edinburgh. But with the vastly improved data from JWST, he says, he and his team were able to measure the ages of stars in those remote galaxies.

      Carnall and colleagues turned their attention to the spectra of the distant galaxies just a few days after the SMACS image was released. They measured the redshifts of 10 galaxies, five of which were particularly distant, the team reports in a paper submitted to arXiv.org on July 18. One had already been highlighted as one of the most distant galaxy ever seen, with light that was emitted just 500 million years after the Big Bang 13.8 billion years ago. The other four shone as late as 1.1 billion years after the Big Bang.

      All 10 galaxies were relatively young when they emitted the light captured by JWST, Carnall says. They had all switched on their star formation just a few million years earlier. That’s not especially surprising, but it is interesting.

      “The ability to look at these small, faint galaxies … gives you a sense of how all galaxies must look when they start forming stars,” Carnall says.

      Scientists hope to use JWST to find the first instances of star formation ever. Other early results suggest they’re already getting close.

      Some galaxies in a JWST image of another cluster may hearken from an even earlier time, as early as 300 million years after the Big Bang, two research teams report in a pair of papers submitted to arXiv.org on July 19. One of those galaxies seems to have already built up a spiral disk about a billion times the mass of the sun, which is surprisingly mature for such an early galaxy.

      And a tally of galaxies seen in the SMACS 0723 image suggests that galaxies with mature disks, rather than disorganized blobs or ones made up mostly of dark matter, may have been more common in the very early universe than previously thought, another team reports in an arXiv.org paper submitted July 19. That means those early disks might not be outliers.

      “Definitely these galaxies are a big deal, but it remains to be seen how exciting they will look in the context of a few months’ progress with JWST,” Carnall says. The best is yet to come.

      [embedded content]
      Exploded stars, colliding galaxies, and beautiful clouds feature in the first space photos released by The James Webb Space Telescope July 12. More

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      Clouds in the Milky Way’s plasma bubbles came from the starry disk — and far beyond

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      Huge bubbles of plasma billowing out from the Milky Way’s center might contain scraps from all over the galaxy — and beyond.

      A new look at gas clouds in the galaxy’s Fermi bubbles shows that the clouds contain stuff from the galaxy’s starry disk and from some mysterious other source. The finding could shed light on how galaxies in general live and die, astronomers report July 18 in Nature Astronomy.

      The Fermi bubbles are giant blobs of plasma, tens of thousands of light-years tall, that extend on either side of the Milky Way’s galactic disk. When the bubbles were discovered in 2010, astronomers thought they could have been formed by newborn stars (SN: 11/9/10). These days, many astronomers are instead convinced the bubbles could have been blown by a massive, long-ago burp emitted from the galaxy’s supermassive black hole.

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      In the years that followed the discovery, astronomers also spotted clouds of relatively cool gas that seem to flit around within the bubbles, high above the starry disk. “We call them high velocity clouds, because we’re not very good at naming things,” says astrophysicist Trisha Ashley of the Space Telescope Science Institute in Baltimore.

      Scientists thought the clouds had been ripped from the Milky Way’s bright starry disk and sent flying when the Fermi bubbles formed. That assumption has been used to calculate things like the age of the bubbles, which could offer a clue to their origins.

      “It made sense, it was a logical assumption,” Ashley says. “But no one had ever tested the origin of these clouds.”

      Now Ashley and colleagues have made a first effort to figure out where the clouds come from — and found a surprising answer.

      Using new and archived data from several telescopes, she and her team measured the metal content — the abundances of all the elements heavier than helium — in 12 high velocity clouds entrenched in the Fermi bubbles. Then the researchers compared the clouds’ chemistries to those of stars in the Milky Way’s disk. If the clouds really did come from the disk, they should have metal contents like the sun and other disk stars, Ashley says. If not, their metal contents should be lower.

      The team found a wide range of metals in the clouds, from less than a fifth of the sun’s to more than the sun’s. That means “these clouds have to originate in both the disk of the Milky Way and the halo of the Milky Way,” she says, referring to the chaotic cloud of gas and dust that surrounds the galaxy and provides it with fuel for new stars (SN: 7/12/18). “We haven’t figured out any other explanation.”

      How those clouds got into the halo in the first place is still an open question, says Jessica Werk, an astronomer at the University of Washington in Seattle who was not involved in the study.

      “There’s a number of ways these clouds can be produced, a number of origins and a number of fates,” she says. The clouds could have condensed within the halo on their own, or they could have been ripped from smaller galaxies cannibalized by the Milky Way, or a number of other origin stories (SN: 7/24/02). “This cycle in general is a very messy process.”

      That messiness could help predict how the Milky Way’s star formation could change in the future. Cold gas clouds like these are the fuel for future star formation. If these clouds were born in the Milky Way’s gaseous halo but are being buoyed up by the Fermi bubbles instead of falling into the disk to form stars, that could eventually slow down the Milky Way’s star forming factories.

      But if the gas clouds do end up forming new stars, that could mean the Milky Way is building new stars from a variety of cosmic sources.

      “Ultimately what people are interested in is, how does the Milky Way sustain its star formation for a long time?” Werk says. “This tells you it’s not just one thing.”

      Studying these bubbles and clouds can help astronomers understand other galaxies, too.

      “We can see these things going on in other galaxies,” Ashley says. “But we have a front row seat to this one.” More