Ghostly particles from space are giving us a new view of our galaxy.



Known as neutrinos, these subatomic particles have little mass and no electric charge. Theyre sometimes called ghost particles. Thats because they easily pass without a trace through gas, dust and even stars. High-energy neutrinos zip everywhere throughout the cosmos, carrying information about distant places. But where the particles come from has typically been a mystery.



Lets learn about ghost particles



Now, researchers found the first signs of high-energy neutrinos coming from within our Milky Way. They mapped the particles to create a new image of our galaxy. Its the first made with something other than light.





The map also hints at possible sources for these high-energy neutrinos. They could be the remains of past supernovas star explosions. Or they might come from the cores of collapsed supergiant stars or other unidentified objects. More research is needed to figure out the sources for all these neutrinos.



The new map of our galaxy was unveiled June 30 in Science.



Previously, only a few high-energy neutrinos have been traced back to their potential birth. They all came from outside the Milky Way. Two appeared to come from black holes shredding their companion stars. Others came from a type of galaxy called a blazar.



Explainer: Stars and their families



Its clear now that researchers are spotting neutrinos from both inside and outside our galaxy, says Kate Scholberg. Shes a physicist at Duke University in Durham, N.C., who did not take part in the new mapping project. Theres so much more to learn, she says. It can be tremendous fun to figure out how to see the universe with neutrino eyes.



Those neutrino eyes might one day allow us to see distant objects in a way that no other telescopes can match.



Some telescopes rely on visible light. Others pick up X-rays, gamma rays or the charged particles that make up cosmic rays. All of those types of light can be deflected or absorbed as they travel through space. Neutrinos, though, can cross huge expanses without being deflected. This allows the particles to tell us about very distant objects.




Three ways to map the Milky Way



Here are views of the Milky Way in visible light (top), gamma rays (middle) and high-energy neutrinos (bottom). Dust obscures portions of the visible-light map, and a variety of sources can generate gamma rays. Neutrinos have the potential to pinpoint remnants of supernovas, cores of collapsed stellar giants and other cosmic features.


IceCube Collaboration/Science 2023IceCube Collaboration/Science 2023





New look at old data



The ability of neutrinos to pass through things so easily also makes them extremely hard to detect. Scientists found the Milky Way particles using a neutrino detector in Antarctica. Called IceCube, this detector is embedded deep in the ice. To better detect ghostly neutrinos, its enormous. Its 5,160 sensors are arranged in a cube one kilometer (3,281 feet) on each side.



Even so, the experiment sees only a tiny share of the neutrinos that zip through space. IceCube scientists observe 100,000 or so neutrinos a year. Some of these neutrinos leave tracks in the detector. The scientists can sometimes trace these tracks back to the neutrinos source. Most of the neutrino signals that IceCube picks up, though, are a type called a cascade event. These leave bursts of light in the detector, but do not reveal a neutrinos origins as well as tracks can.



Astronomers used to throw away data on cascade events, says Naoko Kurahashi Neilson. Shes a physicist at Drexel University in Philadelphia, Pa. Those data can hold useful information about where the neutrinos come from. Its just hard to pick out which of those tens of thousands of cascade events are most important.





Kurahashi Neilson and her team took up the challenge. They dug through a decade of IceCube cascade-event data. They enlisted the help of an artificial-intelligence system known as a neural network. You can train the neural nets to identify which events are worth keeping, Kurahashi Neilson explains.



She pioneered this approach in 2017. Over the years, Kurahashi Neilson has steadily improved it. She and her colleagues have now used it to identify the neutrinos used to make the new map.



Its an impressive analysis, Scholberg says. And the technique may have the potential to be developed even more. Clearly a lot more work needs to be done, she says. But its very exciting to see the basic expectation [of Milky Way neutrinos] verified.

Pulsar (noun, PUHL-sahr)



Pulsars are dense, quickly spinning cores of dead stars that blast radio waves into space.



When a star thats a few times as big as the sun dies, it shoots most of its mass off into space in a huge explosion. That explosion is called a supernova. But the core of the star collapses in on itself and forms an ultra-dense neutron star. All that mass clumps together under the force of gravity. That causes the dead star to spin faster, just like an ice skater pulling in their arms during a turn. Neutron stars can spin faster than the tires on a race car at top speed anywhere from once every few seconds to hundreds of times per second. Thats millions of times faster than the Sun spins.





A pulsar is a special kind of neutron star that blasts out two beams of radio waves in opposite directions. As the dead star spins, those beams sweep through space like the lights on a lighthouse. If Earth is in the path of one of those beams, we see a flash of radio waves every time it sweeps past us. That makes the pulsar appear to pulse at very regular intervals.



This animation shows a pulsars radio beams (purple) sweeping through space. When one of the beams passes over Earth, the pulsar appears to flash.



Astronomer Jocelyn Bell Burnell first discovered pulsars in 1967. At first, some scientists thought the radio beams she saw might be coming from aliens. That was because the pulses were so regular. But then Bell Burnell found radio pulses coming from a different part of space, far from the first signal. It was unlikely that two groups of aliens were signaling us at the same time from so far apart, so scientists looked for a different explanation. They eventually learned the radio waves were coming from pulsars scattered throughout space.



Scientists today use pulsars to make maps of space and keep time in the cosmos. Pulsars can also be used study the fundamental laws of physics that rule the universe.



In a sentence



Scientists time the radio flashes from pulsars to look for gravitational waves.



Check out the full list of Scientists Say.

Scientists may have just found the longest gravitational waves yet.



Gravitational waves are ripples in the fabric of spacetime. Kicked up by massive objects, they roll through the universe like water waves on the surface of the ocean. The newfound gravitational waves are light-years long. That means it would take years for light to travel the distance of a single ripple.



Explainer: What are gravitational waves?



Whats more, these waves wash through the universe nonstop. They constantly jostle Earth and the rest of our galaxy.





Pairs of huge supermassive black holes are thought to trigger these waves. Those black-hole behemoths sit at the centers of galaxies. Scientists think that when two galaxies collide, their black holes pair up and orbit each other. This action could churn up those gravitational waves in spacetime.



Indeed, across the universe, galaxies often mingle and merge. As they do, scientists had suspected their supermassive black holes would orbit each other. In the process, these black holes would give off gravitational waves. In fact, they should pump out waves nonstop for millions of years. Many supermassive-black-hole pairs in the many merging galaxies across the cosmos would send out their spacetime ripples at once. This, scientists thought, should create a constant mishmash of very long gravitational waves.



Explainer: What are black holes?



On June 28, researchers shared the first clear evidence of such a background of gravitational waves. Those data came from several teams around the world.



Scientists must confirm that the newly spotted waves are real and that they do come from pairs of huge black holes. But if so, its miraculous, says Meg Urry. Shes an astrophysicist at Yale University. Thats in New Haven, Conn.



Confirming the new findings would offer the first proof that the biggest black holes in the cosmos can spiral into each other and merge. Its extremely interesting, Urry says. The reason? We have essentially no handle on what the most massive black holes are doing.



Catching a new kind of wave



Since 2015, scientists have spotted lots of gravitational waves. Some have come from smashups between neutron stars. Others have come from colliding black holes. But the black holes in those collisions were small, by cosmic standards. Most were less than 100 times the mass of our sun. Their smashups created blips of gravitational waves that detectors on Earth felt for mere fractions of a second.



Those supermassive black holes thought to cause the newfound gravitational waves are entirely different beasts. Each can have the mass of millions or billions of suns.



The Earth is just randomly bumping around on this sea of gravitational waves, says Maura McLaughlin. Shes an astrophysicist at West Virginia University in Morgantown.





Compared to the gravitational waves seen before, this is a very different sort of thing, says Daniel Holz. This astrophysicist works at the University of Chicago, in Illinois. He and others have used the LIGO detector to spot gravitational-wave blips from small black-hole smashups.



To find waves from supermassive black holes required a whole new technique.





Peering at pulsars



For this new research, scientists looked to objects called pulsars. Theyre spinning remnants of exploded stars. Like celestial lighthouses, pulsars emit beams of radio waves as they spin. Their beams sweep past Earth at regular intervals. Those flashing beams of radio waves are picked up, like the precise ticks of a clock, by telescopes on Earth.



Gravitational waves can stretch and squeeze the space between a pulsar and Earth. In that way, such ripples in spacetime could cause a pulsars ticks to reach Earth early or late. Scientists have now used this effect to search for the gravitational waves from supermassive black holes as they roll through space.



A project called NANOGrav has watched dozens of pulsars for 15 years. (NANOGrav is short for North American Nanohertz Observatory for Gravitational Waves.) The NANOGrav team now thinks it finally has evidence of gravitational waves from pairs of supermassive black holes. The team just shared its findings in Astrophysical Journal Letters.



Scientists searched for gravitational waves by watching dozens of spinning stars called pulsars. Here, each pulsar is shown as a blue dot against a gray illustration of our Milky Way galaxy. The yellow star (near center) shows where Earth sits in the Milky Way.NANOGrav


Its really invigorating stuff, says Michael Keith. Hes an astrophysicist at the University of Manchester in England. Hes also a member of the European Pulsar Timing Array, or EPTA.



The EPTA team spent an even longer time staring at pulsars about 25 years. We were starting to think maybe the signal is just so weak, well never ever find it, Keith says. But like NANOGrav, EPTA has now seen evidence for gravitational waves altering pulsar signals.



EPTAs results have been accepted in the journal Astronomy and Astrophysics. The European group teamed up with researchers from the Indian Pulsar Timing Array to do the work. Teams from Australia and China have now shared evidence for gravitational waves from pairs of supermassive black holes, too.



Astronomers used a variety of radio telescopes to view pulsars in their hunt for gravitational waves. One of those telescopes was the Effelsberg radio telescope (shown) in Germany.Tacken, MPIfR


Its not over yet



Some scientists had thought that supermassive black holes in merging galaxies would never draw close enough to merge. In that case, they wouldnt give off gravitational waves like the ones scientists think they have now observed.



Its actually been a sore spot for our field for many years, Chiara Mingarelli says. Mingarelli is an astrophysicist on the NANOGrav team. Shes based at Yale University.



But if the new gravitational-wave signal is real, it seems to be stronger than expected. That suggests that supermassive black holes spiraling into each other are common. This, in turn, hints that mergers between such black holes also are common.



But none of the teams sharing new data say they have for sure detected gravitational waves from huge black-hole pairs. They just say theyve found strong evidence for this. Thats because each of their observations comes with some uncertainty. In the future, the separate teams plan to join forces. Combining their data may help confirm the detection.



Still, even if the waves are real, its possible they dont come from pairs of monster black holes. Such huge black holes appear to be the simplest explanation. Still, researchers cant rule out a more exotic one. For example, the ripples might have arisen from the fast expansion of the universe just after the Big Bang.



Learning more about supermassive black holes is key to understanding the galaxies that host them. So whatever the source of the potential new gravitational waves, their future study is bound to have ripple effects.

On Jupiter, lightning jerks and jolts a lot like it does on Earth. 



New views of storms on Jupiter hint that its lightning bolts build by lurching forward. Whats more, those staggering steps happen at a similar pace to lightning bolts on our own planet. 



Arcs of lightning on both worlds seem to move like a winded hiker going up a mountain, says Ivana Kolmaov. A hiker might pause after each step to catch their breath. Likewise, lightning on Earth and Jupiter both seem to build by one step, another step, then another, Kolmaov says. Shes an atmospheric physicist at the Czech Academy of Sciences in Prague. Her team shared the new findings May 23 inNature Communications.  





The discovery about Jupiters lightning doesnt just offer new insights into this gas giant. It could also help aid in the search for alien life. After all, experiments hint that lightning on Earth could have forged some of the chemical ingredients for life. If lightning works a similar way on other worlds, it might produce lifes building blocks on distant planets, too. 



Lightning, step by step 



Here on Earth, winds within thunderclouds whip up lightning. The winds cause many ice crystals and water droplets to rub together. As a result, those tiny bits of ice and water become electrically charged. Bits with opposite charges move to opposite sides of the clouds, building up charge on either end.  



Lets learn about lightning



When that charge buildup gets big enough, electrons are released the lightning takes its first step. From there, the surging electrons repeatedly rip electrons off molecules in new segments of air and rush into those segments. So the bolt of lightning leaps forward at tens of thousands of meters per second, on average. 



Scientists thought Jupiters lightningmight also form by ice crystals and water droplets colliding. But no one knew whether the alien bolts grew step by step, as they do on Earth, or if they took some other form. 



Views from Juno 



Kolmaovs group looked at data from NASAs Juno spacecraft. Specifically, they looked at pulses of radio waves given off by Jupiters lightning. The data included hundreds of thousands of radio wave pulses from lightning over five years. 



Radio waves from each lightning bolt seemed to happen about once per millisecond. On Earth, lightning bolts that stretch from one part of a cloud to another pulse at about the same rate.This hints that Jupiters lightning builds in steps that are hundreds to thousands of meters long, too. 







Step-by-step lightning is not the only possible explanation for what Juno saw, says Richard Sonnenfeld. Hes an atmospheric physicist who wasnt involved in the study. He works at the New Mexico Institute of Mining and Technology in Socorro.   



The radio pulses could have come from electrons running back and forth along bolts of lightning, Sonnenfeld says. On Earth, such currents cause some bolts to appear to flicker. Still, he says, stop-and-go lightning formation is a perfectly reasonable explanation for the data. 

Hunting for aliens might sound like science fiction. But it’s a serious science. Alien-seeking researchers don’t chase down UFOs, though. Some use telescopes to listen for messages broadcast by alien civilizations. Others peer at distant words for evidence of life.



No aliens have been found yet. But it’s a big universe. Astronomers have found thousands of planets orbiting other stars. And there may be billions more worlds still to be discovered. Some may even have moons that can support life. That’s a lot of potential alien real estate. Over the last 60 years, astronomers have scoured only a tiny bit of it for interstellar messages. The area searched so far is like a hot tub’s worth of water out of all the world’s oceans.



See all the entries from our Lets Learn About series



Some people think we’d have a better chance of meeting aliens if we introduce ourselves. That is, beam our own messages into space. These messages could be written in mathematical patterns. (Math is thought to be a universal language.) One such message was sent from the Arecibo telescope in Puerto Rico in 1974. But other scientists say this is a bad idea. We might not want to advertise our existence to unfriendly aliens.





There may also be aliens that aren’t able to send or read messages. Some planets may be home to simple, even microscopic life forms. To find those worlds, astronomers look for new worlds in the so-called habitable zone. This is the area around a star where a planet would be just warm enough to have liquid water. That’s important because water is essential for all known life. One such planet may orbit the nearest star to our sun.



A planet may not have to look just like Earth, though, to be a good home for aliens. Some hardy creatures on our own planet thrive in seemingly unlivable conditions. Microbes at the seafloor bask in scalding water. Meanwhile, microbes nestled in Antarctic ice withstand freezing cold. Other critters slurp up toxic chemicals or bathe in acid. Learning about these “extremophiles” broadens our view of what places in the cosmos might be livable.





Microbial aliens might also be found closer to home. Saturn’s moon Enceladus is a good place to look. So is Jupiter’s moon Europa. Both have oceans of liquid water encased in their icy crusts. Mars could even host life in a lake near its south pole. A recent survey suggested that most Americans would welcome finding alien microbes.



The question of whether we are alone in the universe has captured peoples imaginations for millennia. And the answer has two equally mind-blowing possibilities.  In all the vast expanse of outer space, either we are completely alone or we are not.



Want to know more? Weve got some stories to get you started:



Worlds deepest zoo harbors clues to extraterrestrial life Scientists have found a wide range of life deep below Earths surface. Those discoveries could inform the search for life on other planets. (6/15/2017) Readability: 6.6



Only a small fraction of space has been searched for aliens How little? A volume equivalent to a hot tubs worth of the Earths oceans. (10/24/2018) Readability: 8.2



Should we call out to space aliens? To speed up the search for extraterrestrials, some scientists recommend sending signals to space. Others disagree. (3/21/2017) Readability: 8.0





Heres how astronomers can tease out what gases exist in an exoplanets atmosphere and find clues about whether that world might be habitable.



Explore more



Scientists Say: Exomoon



Explainer: What is a planet?



Lets learn about exoplanets



Profile: Looking for life beyond the solar system



Keeping space missions from infecting Earth and other worlds



Finding living Martians just got a bit more believable



Most Americans would welcome a microbial E.T.



Will we know alien life when we see it?



A trail of cosmic dust may lead to alien life



Planets with hydrogen skies could harbor life



Cool Jobs: Reaching out to E.T. is a numbers game



Activities



Word find



The message to alien civilizations sent out by the Arecibo Radio Telescope in 1974 was a picture. It included a basic sketch of a person, the solar system and other information. But in order to beam that picture into space, scientists had to translate it into binary code. Thats a series of 1s and 0s. Learn how to read and create your own binary code messages with this activity from the Rio Tinto Alcan Planetarium in Montreal, Canada.

A long string of galaxies appears to form an arc stretching more than 3 billion light-years across the distant universe. If the arc turns out to be real, it would challenge a basic idea about how the cosmos is structured. Its known as the cosmological principle. And it holds that no matter where you look in the universe, on large scales matter will be distributed fairly evenly.



If it now turns out that this is not true as the newfound arc suggests it would overturn cosmology as we know it, said Alexia Lopez on June 7. She spoke at a news conference at a virtual meeting of the American Astronomical Society. It would mean, she said, that our standard model, not to put it too heavily, kind of falls through.



As a cosmologist, Lopez studies the origins and evolution of the universe. She works at the University of Central Lancashire in Preston, England. She was part of a team that discovered the distant structure. They call it simply the Giant Arc.



Astronomers discovered what they say is a giant arc of galaxies (smile-shaped curve in the middle of this image) by using the light from distant quasars (blue dots) to map out where in the sky that light got absorbed by magnesium atoms in the halos (dark spots) that surround foreground galaxies.A. Lopez



The arc turned up as the researchers were studying images captured as part of the Sloan Digital Sky Survey. That survey, which covers about one-third of the sky, includes the most detailed three-dimensional maps of our universe. It includes light spectra for more than three million astronomical objects.



Lopezs team focused on light from some 40,000 quasars. These are the glowing cores of giant galaxies. Yet they are so distant they appear as mere points of light. On its way to Earth, some of that light gets absorbed by atoms in and around galaxies nearer to us. This absorption creates a signature change in the light that eventually reaches telescopes on Earth or in space.





The Giant Arcs signature is due to magnesium atoms. Each has lost one electron. Theyre glowing in the halos of galaxies about 9.2 billion light-years away. Quasar light absorbed by those atoms traces out a nearly symmetrical curve. That curve contains dozens of galaxies. Lopez reports that together they span about one-fifteenth the radius of the observable universe.



That arc is invisible to the human eye. But if you could see it from Earth, it would span about 20 times the width of the full moon.





See nearly 400,000 galaxies in this animation, which contains images of the actual galaxies in these positions (or sometimes their near cousins). It was made from data derived from release 7 of the Sloan Digital Sky Survey (SDSS). The animations come from Miguel Aragon and Alex Szalay of Johns Hopkins University and Mark Subbarao of Chicagos Adler Planetarium.



The arc as cosmic dilemma



The problem is that this arc makes part of the sky seem too organized. The galaxies are not as evenly distributed as astronomers have always thought they should be.



As such, this finding is a very fundamental test of the hypothesis that the universe is homogeneous on large scales, says Subir Sarkar. Hes an astrophysicist at the University of Oxford in England. Although he studies large-scale structures in the cosmos, he did not take part in the new work. If the Giant Arc is real, he says, this is a very big deal.



But not all researchers are convinced the arc is real. Our eye has a tendency to pick up patterns, Sarkar notes. For instance, he points out that some people have claimed to see Stephen Hawkings initials written in fluctuations of the background cosmic microwave radiation. This is the oldest light in the universe.





Lopez ran three mathematical tests to figure out the odds that galaxies would line up in a giant arc just by chance. All three suggest that the structure is real. One test surpassed physicists gold standard that the odds of it being a statistical fluke should be less than 0.00003 percent.



That sounds pretty good, but it may not be good enough, Sarkar says. Right now, he says, I would say the evidence is tantalizing, but not yet compelling. 



More observations may be needed to firmly support or refute the presence of a Giant Arc.



Explainer: Stars and their families



But if the Giant Arc is real, it would join a growing group of large-scale structures in the universe that, when taken together, break the standard model of cosmology. This model assumes that when you look at large enough volumes of space above about 1 billion light-years across matter will map out evenly. The Giant Arc, however, appears about three times as long as that threshold.



And its not the only such seeming anomaly. There are a number of other large structures in the sky. These include the Sloan Great Wall, the Giant Gamma-Ray Burst Ring and the Huge Large Quasar Group.



With one large-scale structure, that could just be a statistical fluke, Lopez says. Thats not the problem. All of [those big structures] combined is what makes the problem even bigger.

The cosmos keeps outdoing itself.



Extremely energetic light from space is an unexplained wonder. Scientists dont know where that light comes from, exactly. And now astronomers have spotted this light, called gamma rays, at higher energies than ever before.



You cant see gamma rays with your eyes. They are much more energetic than the light that we can see. So you need a fancy detector to spot them. The Large High Altitude Air Shower Observatory, LHAASO, is an experiment in China. It searches for extremely high energy gamma rays.



Understanding light and other forms of energy on the move





LHASSO spotted more than 530 of these brilliant rays with more than 0.1 quadrillion electron volts of energy. The highest-energy of these gamma rays was about 1.4 quadrillion electron volts. Thats a lot. And its the highest-energy light ever seen.



Previously, the most energetic gamma ray known had less than a quadrillion electron volts.



For comparison, the super-energetic protons in the largest particle accelerator on Earth the Large Hadron Collider only reach trillions of electron volts.



The researchers reported their new observations online May 17 in Nature.





Scientists spotted 12 gamma-ray hot spots. These are parts of the sky from which the gamma rays emanate.



Those hot spots hint that our galaxy, the Milky Way, has powerful particle accelerators. But those particle accelerators arent made by humans. Instead, they come from violent events in the cosmos. They might be exploding stars, for example. Such violent events make electric and magnetic fields. Those can speed up protons and electrons. Those fast particles can then produce gamma rays with a lot of energy. That can happen when protons interact with other matter in space, for example.



Scientists arent sure what could produce gamma rays with the extreme energies observed. But the new observations point to two possibilities. One hot spot was associated with the Crab Nebula. Thats the turbulent remains of an exploded star. Another possible source was the Cygnus Cocoon. Thats a region where massive stars are forming. The stars blast out intense winds in the process.



LHAASO is located on Haizi Mountain in Chinas Sichuan province. It is not yet fully operational. Its due to be completed later this year. Then, it could find even more gamma rays.

All known stars are made of ordinary matter. But astronomers havent completely ruled out that some could be made of antimatter.



Antimatter is the oppositely charged alter-ego of normal matter. For instance, electrons have antimatter twins called positrons. Where electrons have negative electric charge, positrons have positive charge. Physicists think the universe was born with equal amounts of matter and antimatter. Now the cosmos appears to have almost no antimatter.



Space-station data have recently cast doubt on this idea of a practically antimatter-free universe. One instrument might have seen bits of antihelium atoms in space. Those observations have to be confirmed. But if they are, that antimatter could have been shed by antimatter stars. That is, antistars.



Explainer: What are black holes?





Intrigued by this idea, some researchers went hunting for potential antistars. The team knew that matter and antimatter annihilate each other when they meet. That could happen when normal matter from interstellar space falls onto an antistar. This type of particle annihilation gives off gamma rays with certain wavelengths. So the team looked for those wavelengths in data from the Fermi Gamma-ray Space Telescope.



And they found them.



Fourteen spots in the sky gave off the gamma rays expected from matter-antimatter annihilation events. Those spots did not look like other known gamma-ray sources such as spinning neutron stars or black holes. That was further evidence that the sources could be antistars. Researchers reported their find online April 20 in Physical Review D.



Rare or possibly hiding?



The team then estimated how many antistars could exist near our solar system. Those estimates depended on where antistars would most likely be found, if they truly existed.



Any in the disk of our galaxy would be surrounded by lots of normal matter. That could cause them to emit lots of gamma rays. So they should be easy to spot. But the researchers only found 14 candidates.



That implies that antistars are rare. How rare? Perhaps only one antistar would exist for every 400,000 normal stars.



Understanding light and other forms of energy on the move



Antistars could exist, however, outside the Milky Ways disk. There, they would have less chance to interact with normal matter. They also should emit fewer gamma rays in this more isolated environment. And that would make them harder to find. But in that scenario, one antistar could lurk among every 10 normal stars.



Antistars are still only hypothetical. In fact, proving any object is an antistar could be nearly impossible. Why? Because antistars are expected to look almost identical to normal stars, explains Simon Dupourqu. Hes an astrophysicist in Toulouse, France. He works at the Institute of Research in Astrophysics and Planetology.





It would be much easier to prove the candidates found so far are not antistars, he says. Astronomers could watch how gamma rays from the candidates change over time. Those changes might hint at whether these objects are really spinning neutron stars. Other types of radiation from the objects might point to their actually being black holes.



If antistars exist, that would be a major blow for our understanding of the universe. So concludes Pierre Salati, who wasnt involved in the work. This astrophysicist works at the Annecy-le-Vieux Laboratory of Theoretical Physics in France. Seeing antistars would mean that not all of the universes antimatter was lost. Instead, some would have survived in isolated pockets of space.



But antistars probably could not make up for all the universes missing antimatter. At least, thats what Julian Heeck thinks. A physicist at the University of Virginia in Charlottesville, he too did not take part in the study. And, he adds, you would still need an explanation for why matter overall dominates over antimatter.

NASA has released the largest picture ever taken. It is of the Andromeda galaxy, The amount of stars in it is just unreal!

Incredible Felix Baumgartner jump from outer space.