Latest news with #TheAstrophysicalJournalLetters
Business Mayor
19-05-2025
- Science
- Business Mayor
Not one, but two massive black holes are eating away at this galaxy
Astronomers have discovered nearly 100 examples of massive black holes shredding and devouring stars, almost all of them where you'd expect to find massive black holes: in the star-dense cores of massive galaxies. University of California, Berkeley, astronomers have now discovered the first instance of a massive black hole tearing apart a star thousands of light years from the galaxy's core, which itself contains a massive black hole. The off-center black hole, which has a mass about 1 million times that of the sun, was hiding in the outer regions of the galaxy's central bulge, but revealed itself through bursts of light generated by the spaghettification of the star — a so-called tidal disruption event, or TDE. In a TDE, the immense gravity of a black hole tugs on a star — similar to the way the moon raises ocean tides on Earth, but a lot more violently. 'The classic location where you expect massive black holes to be in a galaxy is in the center, like our Sag A* at the center of the Milky Way,' said Yuhan Yao, a Miller Postdoctoral Fellow at UC Berkeley who is lead author of a paper about the discovery recently accepted for publication in The Astrophysical Journal Letters (ApJL) . 'That's where people normally search for tidal disruption events. But this one, it's not at the center. It's actually about 2,600 light years away. That's the first optically discovered off-nuclear TDE discovered.' The galaxy's central massive black hole, about 100 million times the mass of our sun, is also gorging itself, but on gas that has gotten too close to escape. Studies of massive black holes at galactic centers tell astronomers about the evolution of galaxies like our own, which has one central black hole — called SagA* because of its location within the constellation Sagittarius — weighing in at a puny 4 million solar masses. Some of the largest galaxies have central black holes weighing several 100 billion solar masses, presumably the result of the merger of many smaller black holes. Finding two massive black holes in the center of a galaxy is not surprising. Most large galaxies are thought to have massive black holes in their cores, and since galaxies often collide and merge as they move through space, large galaxies should occasionally harbor more than one supermassive black hole — at least until they collide and merge into an even bigger black hole. They typically hide in stealth mode until they reveal their presence by grabbing nearby stars or gas clouds, creating a short-lived burst of light. These are rare events, however. Astronomers calculate that a massive black hole would encounter a star once every 30,000 years, on average. Read More Starwatch: Ursids meteor shower to appear in largely dark sky The new TDE, dubbed AT2024tvd, was detected by the Zwicky Transient Facility, an optical camera mounted on a telescope at Palomar Observatory near San Diego, and confirmed by observations with radio, X-ray and other optical telescopes, including NASA's Hubble Space Telescope. 'Massive black holes are always at the centers of galaxies, but we know that galaxies merge — that is how galaxies grow. And when you have two galaxies that come together and become one, you have multiple black holes,' said co-author Ryan Chornock, a UC Berkeley associate adjunct professor of astronomy. 'Now, what happens? We expect they eventually come together, but theorists have predicted that there should be a population of black holes that are roaming around inside galaxies.' The discovery of one such roaming black hole shows that systematic searches for the signature of a TDE could turn up more rogue black holes. The find also validates plans for a space mission called LISA — the Laser Interferometer Space Antenna — that will look for gravitational waves from mergers of massive black holes like these. 'This is the first time that we actually see massive black holes being so close using TDEs,' said co-author Raffaella Margutti, a UC Berkeley associate professor of astronomy and of physics. 'If these are a couple of supermassive black holes that are getting closer together — which is not necessarily true — but if they are, they might merge and emit gravitational waves that we'll see in the future with LISA.' LISA will complement ground-based gravitational wave detectors, such as LIGO and Virgo, which are sensitive to the merger of black holes or neutron stars weighing less than a few hundred times the mass of our sun, and telescopic studies of pulsar flashes, such as the Nanograv pulsar timing array experiment, which are sensitive to gravitational waves from the mergers of supermassive black holes weighing billions of solar masses. LISA's sweet spot is black holes of several million solar masses. LISA is slated to be launched in the next decade. Transient outbursts Because black holes are invisible, scientists can only find them by detecting the light produced when they shred stars or gas clouds and create a bright, hot, rotating disk of material that gradually falls inward. TDEs are powerful probes of black hole accretion physics, Chornock said, revealing how close material can get to the black hole before being captured and the conditions necessary for black holes to launch powerful jets and winds. The most productive search for TDEs has used data from the Zwicky Transient Facility, originally built to detect supernova explosions, but also sensitive to other flashes in the sky. The ZTF has discovered nearly 100 TDEs since 2018, all within the cores of galaxies. X-ray satellites have also detected a few TDEs, including two in the outskirts of a galaxy that also has a central black hole. In those galaxies, however, the black holes are too far apart to ever merge. The newly discovered black hole is close enough to the core's massive black hole to potentially fall toward it and merge, though not for billions of years. Yao noted that two alternative scenarios could explain the presence of the wandering black hole in AT2024tvd. It could be from the core of a small galaxy that merged with the larger galaxy long ago and is either moving through the larger galaxy on its way out or has become bound to the galaxy in an orbit that may, eventually, bring it close enough to merge with the black hole at the core. Erica Hammerstein, another UC Berkeley postdoctoral researcher, scrutinized the Hubble images as part of the study, but was unable to find evidence of a past galaxy merger. AT2024tvd could also be a former member of a triplet of black holes that used to be at the galactic core. Because of the chaotic nature of three-body orbits, one would have been kicked out of the core to wander around the galaxy. Searching galaxies for off-center black holes Because the ZTF detects hundreds of flashes of light around the northern sky each year, TDE searches to date have focused on flashes discovered near the cores of galaxies, Yao said. She and Chornock created an algorithm to distinguish between the light produced by a supernova and a TDE, and employed it to search through the 10,000 or so detections by ZTF to date to find bursts of light in the galactic center that fit the characteristics of a TDE. 'Supernovae cool down after they peak, and their color becomes redder,' Yao said. 'TDEs remain hot for months or years and have consistently blue colors throughout their evolution.' TDEs also exhibit broad emission lines of hydrogen, helium, carbon, nitrogen and silicon. Last August, the Berkeley team discovered a burp of light that looked like a TDE, but its location seemed off-center, though within the resolution limits of the ZTF. The researchers suspected the black hole was indeed off center, and immediately requested time on several telescopes to pinpoint its location. These included NASA's Chandra X-ray Observatory, the Very Large Array and the Hubble Space Telescope. They all confirmed its off-nucleus location, with HST providing a distance of about 2,600 light years — about one-tenth the distance between our sun and Sag A*. Though close to the central black hole, the off-nuclear black hole is not gravitationally bound to it. Because the black hole at the core spews out energy as it accretes infalling gas, it is categorized as an active galactic nucleus. Yao and her team hope to find other roaming TDEs, which will give astronomers an idea of how often galaxies and their core black holes merge, and thus how long it takes to form some of the extreme, supermassive black holes. 'AT2024tvd is the first offset TDE captured by optical sky surveys, and it opens up the entire possibility of uncovering this elusive population of wandering black holes with future sky surveys,' Yao said. 'Right now, theorists haven't given much attention to offset TDEs. They primarily predict rates for TDEs occurring at the centers of galaxies. I think this discovery really motivates them to compute rates for offset TDEs, as well.' The 34 co-authors who contributed to the paper come from institutions in the United States, United Kingdom, Sweden, Russia, Germany, Australia and the Netherlands. ZTF is a public-private partnership, with equal support from the ZTF Partnership and the U.S. National Science Foundation.
Daily Record
15-05-2025
- Science
- Daily Record
NASA finds 'monster' black hole 600 million light-years away in 'scene out of a sci-fi movie'
NASA has pinpointed a massive, roaming black hole that is so big they have dubbed the hole 'Super Jaws' It is easy to get swept away in the wonders of space. There is extensive and ongoing research on space, with scientists having even struck gold recently when trying to reconstruct what happened after the Big Bang. However, NASA has stumbled upon another mind-blowing discovery - a massive roaming black hole lurking 600 million light-years away that is "like a scene out of a sci-fi movie". Astronomers using NASA telescopes have found 'Space Jaws' - a wandering, supermassive black hole. What's more, an accompanying telescope also revealed that the black hole is offset from the centre of the galaxy. "Within the inky black depths between stars, there is an invisible monster gulping down any wayward star that plummets toward it," a NASA spokesperson excitingly elaborated. "The sneaky black hole betrayed its presence in a newly identified tidal disruption event (TDE) where a hapless star was ripped apart and swallowed in a spectacular burst of radiation. "These disruption events are powerful probes of black hole physics, revealing the conditions necessary for launching jets and winds when a black hole is in the midst of consuming a star, and are seen as bright objects by telescopes." A black hole is a region in space where the pulling force of gravity is so strong that light is not able to escape. The strong gravity occurs because matter has been pressed into a tiny space. This compression can take place at the end of a star's life. Some black holes are a result of dying stars. Because no light can escape, black holes are invisible. However, space telescopes with special instruments can help find black holes. They can observe the behaviour of material and stars that are very close to black holes. So, what does this latest find mean? A TDE happens when an infalling star is stretched or 'spaghettified' by a black hole's immense gravitational tidal forces. The shredded stellar remnants are pulled into a circular orbit around the black hole. This generates shocks and outflows with high temperatures that can be seen in ultraviolet and visible light. 'AT2024tvd is the first offset TDE captured by optical sky surveys," said lead study author Yuhan Yao. "It opens up the entire possibility of uncovering this elusive population of wandering black holes with future sky surveys." The full paper will be published in an upcoming issue of The Astrophysical Journal Letters, but the space agency was surprised to find that this one million-solar-mass black hole doesn't reside exactly in the centre of the host galaxy. This is where supermassive black holes are typically found, and actively gobble up surrounding material. In fact, at the centre of the host galaxy there is a different supermassive black hole weighing 100 million times the mass of the Sun. Hubble's optical precision shows the TDE was only 2,600 light-years from the more massive black hole at the galaxy's centre. That's just one-tenth the distance between our Sun and the Milky Way's central supermassive black hole. Join the Daily Record WhatsApp community! Get the latest news sent straight to your messages by joining our WhatsApp community today. You'll receive daily updates on breaking news as well as the top headlines across Scotland. No one will be able to see who is signed up and no one can send messages except the Daily Record team. All you have to do is click here if you're on mobile, select 'Join Community' and you're in! If you're on a desktop, simply scan the QR code above with your phone and click 'Join Community'. We also treat our community members to special offers, promotions, and adverts from us and our partners. If you don't like our community, you can check out any time you like. To leave our community click on the name at the top of your screen and choose 'exit group'. If you're curious, you can read our Privacy Notice. This bigger black hole spews out energy as it accretes infalling gas, and it is categorised as an active galactic nucleus. Strangely, the two supermassive black holes co-exist in the same galaxy, but are not gravitationally bound to each other as a binary pair. The smaller black hole may eventually spiral into the galaxy's centre to merge with the bigger black hole. But for now, it is too far separated to be gravitationally bound. "Theorists haven't given much attention to offset TDEs," Yuhan went on. "But I think this discovery will motivate scientists to look for more examples of this type of event."
Time of India
06-05-2025
- Science
- Time of India
Scientists discover new minimoons orbiting Earth – what could this mean for our planet's future
For years, the space near Earth was assumed to be fairly well known, particularly in terms of detecting near-Earth objects (NEOs) like asteroids and debris. That perception is being turned on its head by new discoveries. Tired of too many ads? go ad free now According to a recent paper published in The Astrophysical Journal Letters, there could be an undiscovered population of " minimoons "—small natural satellites—around Earth. And what is interesting about these objects is that some of them seem to be debris from the Moon itself. The research highlights the recently identified object 2024 PT5 , an asteroid-like body that shows lunar-like features such as orbital properties and compositional similarities with Moon rock. This finding by planetary scientist Teddy Kareta and his Lowell Observatory team opens up the thrilling possibility that numerous other such pieces are orbiting Earth in silence, leftovers from old lunar impacts. What are minimoons and their role in space science Minimoons are minor bodies temporarily held in Earth's gravity. In contrast to the Moon, which is a natural permanent satellite, minimoons have transient orbits—occasionally staying within the gravitational clutches of Earth for weeks, months, or years before finally breaking free again into solar orbit. Until recently, these objects were thought to be very rare. The first clearly established minimoon of possible lunar origin, Kamo'oalewa, was found in 2021. With the discovery of 2024 PT5, the story is emerging. Researchers are starting to see these objects not as oddities, but as possible members of a larger population that hasn't been seen because they are too small and have too complicated, changing orbits. New evidence suggests 2024 PT5 could be a piece of the moon The identification of 2024 PT5 is especially noteworthy due to its possible lunar origin. Tired of too many ads? go ad free now Its path and spectral character—a method of determining an object's composition from the manner in which it scatters light—effectively mimic those of rocks brought back to Earth by NASA's Apollo missions. This heavily indicates that PT5 could be a piece that was ejected from the surface of the Moon, perhaps by a meteoric impact. Teddy Kareta emphasised the importance of the discovery at the 56th annual Lunar and Planetary Science Conference, saying: 'If there were only one object, that would be interesting but an outlier. If there's two, we're pretty confident that's a population.' In other words, the confirmation of a second minimoon with lunar properties supports the idea that such objects are more common than previously believed. Understanding lunar debris: How high-energy impacts send moon fragments into Earth's orbit Lunar debris is usually created through high-energy impact events, in which meteoroids collide with the lunar surface and send debris into space. A portion of this debris may fall into the Earth's sphere of gravitational influence, becoming temporarily captured. They have chaotic, highly elliptical orbits that set them apart from both standard NEOs and Earth's main Moon. Simulations and tracking models imply that these fragments can be trapped for a few months to a few years, after which they will burn up in Earth's atmosphere, escape Earth's gravity, or be deflected by subsequent gravitational encounters. What minimoons can reveal The implications of minimoons from a scientific perspective are significant. Minimoons provide a one-of-a-kind chance to investigate the Moon's impact record without sending complex sample-return missions to the surface of the Moon. By analysing the composition of the minimoons, scientists can determine the nature of the rock, the age of the rock, and possibly trace it to a particular crater or region of geology on the Moon. This could greatly improve the knowledge of: Geological evolution of the Moon Rate and magnitude of lunar impact events Orbital dynamics of Earth-Moon interactions Kareta compared it to forensic science by saying: "It's like discovering a crime scene has a completely new type of evidence you didn't realise you had before." These pieces are actually natural sample-return missions already underway. From sample return to space mining: The strategic value of minimoons Aside from academic curiosity, minimoons also have significant potential for future missions of exploration. Because they are close and relatively slow-moving relative to other NEOs, they are prime targets for: Robotic spacecraft missions Sample return programs Experimentation with navigation and landing technologies for asteroid mining or deep space missions They provide a valuable stepping stone to deep-space exploration while also facilitating new types of resource analysis and planetary defense testing. 2024 PT5 highlights the need for advanced detection methods The detection of 2024 PT5 emphasises the necessity of more sensitive sky surveys and special observation programs. The majority of existing asteroid detection systems are optimized for discovering larger, brighter objects. Minimoons, being small and faint, need different methods and continuous monitoring in order to be discovered. The development of this capability would greatly improve our knowledge of not just minimoons, but also the dynamic interaction between Earth and its cosmic environment. Also Read |
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First Post
05-05-2025
- Science
- First Post
Where does all the gold come from? Scientists discover the real source
For centuries, gold's celestial origins remained one of astronomy's greatest mysteries. Now, a ground-breaking study has pinpointed the violent cosmic events responsible for forging nearly all the gold in our universe—collisions between neutron stars. read more For years, scientists believed that gold and other heavy elements were forged solely in the violent collisions of neutron stars. But a ground-breaking new study suggests there's another, unexpected cosmic player in this alchemy: magnetars. Published in The Astrophysical Journal Letters, the research identifies magnetar giant flares, brief but immensely powerful explosions from highly magnetised neutron stars as a newly confirmed source of gold production in the universe. Using data from a 2004 gamma-ray burst known as GRB 041219A, researchers discovered telltale signs of a heavy element-forming process known as rapid neutron capture or the r-process within the burst's ejecta. STORY CONTINUES BELOW THIS AD 'What we're seeing is essentially a cosmic gold factory in action,' said lead researcher Dr. Matt Nicholl of the University of Birmingham. 'The JWST's infrared eyes detected clear signatures of tellurium—a heavy element produced through the same process that creates gold—proving these collisions are the universe's primary source of precious metals.' The discovery overturns long-held assumptions that supernovae were the main producers of gold. While dying stars do create lighter elements like carbon and oxygen, neutron star mergers generate staggering amounts of heavier elements through rapid neutron capture (r-process) nucleosynthesis. A single collision can produce gold weighing more than 100 times the mass of Earth's oceans. 'This explains why gold is so rare,' noted co-author Dr. Eleonora Troja of the University of Rome. 'Neutron star mergers are incredibly violent but infrequent events—our galaxy might only see one every 100,000 years.' The team estimates that magnetar flares may account for up to 10% of all the heavy elements like gold, platinum, and uranium in the universe. Unlike neutron star collisions, which are rare and difficult to detect, magnetar flares are more frequent and easier to observe, offering scientists a new window into cosmic element formation. STORY CONTINUES BELOW THIS AD Magnetars are a rare type of neutron star, the ultra-dense remnants of supernova explosions. What sets them apart is their extreme magnetic fields—trillions of times stronger than Earth's—which can twist and snap in violent flares that release more energy in a single second than our sun emits in 100,000 years. The research team traced how these celestial alchemists distribute their precious products across the cosmos. Following a merger, ejected material laced with gold and other heavy elements gets swept up in cosmic winds, eventually becoming incorporated into interstellar gas clouds. Over billions of years, these enriched clouds form new stars and planets, including our solar system. Most of Earth's gold likely arrived during the Late Heavy Bombardment period about 4 billion years ago, when asteroids pummelled our young planet. This extra-terrestrial delivery means the gold in your jewellery was probably forged in a cataclysmic neutron star collision that occurred long before our solar system existed. STORY CONTINUES BELOW THIS AD The study also resolves a longstanding astronomical puzzle. While scientists had theorised about neutron star mergers creating heavy elements since the 1970s, concrete evidence remained elusive until JWST's advanced instruments could analyse the chemical fingerprints of these distant explosions. As astrophysicists continue studying GRB 230307A's afterglow, they expect to find signatures of other precious metals like platinum and uranium. The findings not only rewrite our understanding of cosmic chemistry but also highlight how the most violent events in the universe create the building blocks of planets and the precious metals humans have prized since antiquity. For gold's origin story, it turns out the truth is even more extraordinary than alchemists imagined: all that glitters was literally forged in the heart of colliding stars.
NDTV
04-05-2025
- Science
- NDTV
'Minimoons': Rocks Circling Near Earth Could Be A Chunk Of The Moon
A whole population of 'minimoons' - tiny natural satellites - may be quietly circling near Earth, scientists now believe, after discovering a second Moon-origin rock drifting close to our planet. The newly observed object, named 2024 PT5, was spotted near Earth last August and is thought to be a lunar fragment, possibly blasted off the Moon during a massive impact long ago. This makes it only the second known piece of the Moon found orbiting in near-Earth space. "If there were only one object, that would be interesting but an outlier," said Teddy Kareta, a planetary scientist at Lowell Observatory in Arizona. "If there's two, we're pretty confident that's a population." The findings were published in The Astrophysical Journal Letters in January and presented in March at the 56th Lunar and Planetary Sciences Conference in Texas. 2024 PT5 stood out when it was first observed by astronomers in South Africa, thanks to its unusually slow movement, just 2 metres per second relative to Earth. That made it a promising candidate for the Mission Accessible Near-Earth Object Survey (MANOS), which focuses on finding asteroids that are easiest to reach with spacecraft. The rock, just 26 to 39 feet (8 to 12 metres) wide, didn't look like a typical asteroid. Mr Kareta and his team believe it may have been ejected from the Moon's surface during a violent impact. The discovery suggests that other such fragments might be hiding in near-Earth space. Earth regularly travels through a cloud of debris, both natural and man-made, as it orbits the Sun. Some of it is leftover rock from the early solar system, and scientists keep a close eye on these near-Earth objects (NEOs) in case any pose a threat. Material that gets blasted off the Moon during an impact usually stays close to Earth's orbit, especially the slower pieces. 2024 PT5 was briefly called a minimoon in September because it moved alongside Earth for a short time. But it didn't stay for long and eventually drifted away. Scientists think it will come close to Earth again in 2055. Within a week of the discovery, Mr Kareta and MANOS principal investigator Nick Moskovitz turned the Lowell Discovery Telescope toward 2024 PT5. After analysing the rock in visible and near-infrared light, they found its composition closely resembled moon rocks brought back by the Apollo missions and the Soviet Luna 24 mission. "It's like realising a crime scene has a totally new kind of evidence you didn't know you had before," Mr Kareta told "It might not help you solve the crime right away, but considering the importance of the task, new details to compare are always welcome." This is only the second known lunar fragment spotted in near-Earth space. The first, called Kamo'oalewa, was discovered in 2016 and linked to the Moon in 2021.
