Some of the brightest objects in the universe may also hold the key to understanding how galaxies evolve — especially when gravity transforms them into giant cosmic magnifying glasses.

Using artificial intelligence to search through data from the Dark Energy Spectroscopic Instrument (DESI), astronomers have identified seven promising candidates for quasars acting as gravitational lenses — natural cosmic magnifying glasses created when a massive object's gravity bends and magnifies light from a more distant object.

These unusual systems could help researchers better understand how actively growing supermassive black holes evolve, according to a statement from Ohio State University.

"Quasars are like the baby pictures of a supermassive black hole," Everett McArthur, lead author of the study and a graduate student in astronomy at The Ohio State University, said in the statement. "So exploring how we get from quasars to those black holes is really important."

Quasars are the intensely bright centers of galaxies powered by actively feeding supermassive black holes. Studying these objects can help researchers understand how black holes evolve into the enormous ones found throughout the modern universe. But as these black holes pull in gas and dust, they release so much energy that they can outshine their entire host galaxies, making those galaxies difficult to study.

Rare cases where a quasar acts as a gravitational lens offer a way around that problem, giving astronomers a unique opportunity to observe both the quasar and the distant galaxy whose light is magnified by its gravity.

However, finding these rare alignments can be exceptionally challenging. To uncover them, the research team began with a catalog of roughly 800,000 quasars identified by DESI and used a machine-learning model to search for subtle signatures of gravitational lensing.

Because so few quasars acting as gravitational lenses are known, researchers had little real-world data to train their AI model. Instead, they generated simulated examples of these cosmic alignments, allowing the algorithm to learn what to look for before searching the DESI catalog. The algorithm narrowed the search to about 200 candidates, which researchers then reviewed manually. That process resulted in seven new quasar lens candidates.

The discoveries roughly double the number of known systems found through similar survey searches, according to the statement.

While artificial intelligence played a key role in finding the candidates, the discoveries highlight the scientific potential hidden within the massive datasets produced by modern astronomy. DESI is mapping millions of galaxies and quasars, creating an enormous archive that would be nearly impossible to search by hand.

Follow-up observations will be needed to confirm the newly identified quasar lenses and study their properties in greater detail. If verified, they could offer astronomers a powerful new way to investigate how supermassive black holes shaped the galaxies around them while demonstrating how AI can uncover rare cosmic phenomena hidden within the enormous datasets produced by modern sky surveys.

Their findings were published July 22 in The Astrophysical Journal.

Using NASA's Chandra X-ray space telescope, astronomers have spotted the blisteringly hot exhaust fumes of one the earliest quasars, cosmic "breath" with temperatures as great as 36 million degrees Fahrenheit. This intensely bright titan is powered by a feeding supermassive black hole engine.

The Chandra X-ray telescope observed a relatively silent quasar that existed 2.1 billion years after the Big Bang. The cosmic "exhaust fumes" from this black hole engines extend out for around 100,000 light-years around a quasar at the heart of a still-forming galactic cluster, or "proto-cluster" called MQN01. These blisteringly hot gas structures will eventually become the atmospheres that envelope modern clusters of galaxies, known as the intracluster medium (ICM).

Thus, this research reveals for the first time the exact moment in cosmic history that these galactic atmospheres began to form and gather.

"The central scientific question is to understand how this hot phase forms: what are the physical conditions of the gas during its formation and what processes contribute to its heating," team member Sebastiano Cantalupo of the University of Milan-Bicocca said in a statement.

"[The data] show extraordinary properties of the gas that could provide us with the first insights into how this hot phase of the circumgalactic medium, which we now see as intracluster medium, formed."

Start your engines...

The team behind this research spotted this hot gas structure after 180 hours of X-ray observations conducted by Chandra. Until now, X-ray detections such as this have only been made for quasars that sit in active galactic nuclei (AGNs) at the heart of "radio-loud" galaxies.

The X-ray emissions from these radio galaxies come from jets of particles blasted out from around feeding supermassive black holes at near-light speeds.

But the quasar at the heart of MQN01 differs from these because it is radio-quiet. This means the X-rays detected by Chandra from this quasar are uncontaminated by plasma jets, so the observation is entirely the result of the cosmic "motorbreath" from the quasar.

"We are facing one of the most distant detections of extended thermal X-ray emission associated with the formation of hot gas in dense regions of the universe, which will likely evolve into the known local ICM," Cantalupo said.

"We believe we have identified a phase in its life in which cold gas falls towards the gravitational potential of this massive halo and is heated by gravitational shocks, reaching temperatures of about 20 million Kelvin [36 million degrees Fahrenheit (20 million degrees Celsius)].

"The densities and pressures we measured are high: one to two orders of magnitude higher than those of clusters in our local universe."

The observations of this radio-quiet galaxy were possible thanks to the application of a technique usually used to analyze Seyfert galaxies, which host feeding supermassive black holes in the local universe (the area of space found within 1 billion light-years of Earth). The challenge the team faced was isolating the faint light from the gas from the blinding glare of gas closer to the central black hole.

"We were initially extremely skeptical ourselves," team leader Andrea Travascio of the INAF said. "Given the exceptional nature of the data, we sifted through every alternative explanation: from artificial outflows to instrumental contamination or other unsuspected effects. But each alternative scenario encountered insurmountable theoretical limitations. The thermal explanation is the only one consistent with the physical data."

Travascio and the team are now analyzing archival datasets from hundreds of other quasars to discover if this heating phase is common to protoclusters or if MQN01 is a rarity.

"Considering how unique the result was and also taking into account Chandra's technical difficulties in the final phases of its mission, the satellite has once again demonstrated its extraordinary ability to produce scientifically relevant results even after decades of operation," Travascio said.

The team's research was published on Friday (July 24) in the journal Astronomy & Astrophysics.

Using the Chandra X-ray spacecraft, astronomers have seen a supermassive black hole jet churning and "cooking" gas surrounding a galaxy nicknamed the "red potato." And this potato is seen as it was when the universe was around 2 billion years old.

The galaxy in question is officially designated MQN01 J004131.9-493704 and is located about 11.7 billion light-years from Earth at the intersection of a vast cosmic web along which galaxies formed in the early universe. Originally discovered by the James Webb Space Telescope (JWST), the odd, blob-like appearance of the galaxy is why it has such a peculiar nickname.

The red potato sits in a cosmic "pot" of cold and dense gas. This is a little puzzling, as this should mean that stars are actively forming around it, but that isn't happening. New research offers an explanation: a supermassive black hole in the vicinity of the red potato is churning and heating the galaxy's pot of gas. This could be preventing the gas from cooling and collapsing to birth stellar bodies.

“Stars are not forming like we thought they would, so we went searching for the reason why," team leader Weichen Wang of the University of Milan-Bicocca in Italy said in a statement. "We found there may be a cook in this cosmic kitchen."

An unexpected chef

A supermassive black hole's interference with the red potato was first indicated by the fact that its surrounding gas is unexpectedly turbulent in comparison to similar gas clouds around similar galaxies.

Wang and colleagues set about hunting for the source of this turbulence with Chandra. That's when they found a black hole jet pointed toward the red potato, which they reasoned must be slamming into this ancient galaxy's gas envelope.

"If the black hole's jet is stirring up the gas around the red potato, it could greatly slow down how quickly the galaxy can acquire new, fresh material to form stars," team member Sebastiano Cantalupo of the University of Milan-Bicocca said in the statement. "With the energy from the stirring, the galaxy will starve and not be able to produce new stars at the rate expected for similar galaxies at the same cosmic epoch."

The meddling supermassive black hole is located in a galaxy around 200,000 light-years from the red potato, and this galaxy is actually very actively forming new stars. Indeed, other galaxies in the vicinity of the Red Potato are also birthing new stars.

This discovery, as part of some of the first research to investigate the behavior of gas around non-star-forming galaxies, could be vital in improving our understanding of how neighboring galaxies interact and, occasionally, interfere with each other's evolution.

"The red potato is leaving crumbs of information that may help us track down the answers to some really big questions," team member Andrea Travascio, also of the University of Milan-Bicocca, said. "Quite an important job for a galactic spud like this."

The team's research was published on July 7 in the journal Astronomy & Astrophysics.

Fixing a problem inside one of the world's most sophisticated scientific observatories might seem like the kind of challenge that demands a multimillion-dollar upgrade or revolutionary new technology.

But for scientists working on the Laser Interferometer Gravitational-Wave Observatory (LIGO), which listens for ripples in spacetime generated by cosmic collisions like merging black holes, the solution to a mild but persistent engineering challenge turns out to be as simple as an off-the-shelf camera.

By pairing commercially available thermal imaging cameras with computer models, a team led by Jonathan Richardson at the University of California, Riverside, has developed a technique that corrects tiny, heat-induced distortions in the observatory's mirrors — an elusive flaw that scientists say currently limits how far into deep space the facility can look.

"It doesn't require any new technology development, which is almost unheard of for solving a LIGO instrumentation problem," Richardson said in a statement.

Once incorporated into LIGO's upcoming upgrade, Richardson and his team estimate the fix would extend the observatory's reach by roughly 33 million light-years.

That gain might sound like a drop in the ocean against the unimaginably vast scale of the universe, but because space expands in three dimensions, pushing a detector's reach even slightly opens up an exponentially larger window of space. Being able to look further into the universe will allow astronomers to "hear" many more cosmic ripples, in turn increasing the potential for discovering the universe’s most violent collisions that lie beyond LIGO's reach today.

LIGO detects these cosmic ripples, known as gravitational waves, using twin L-shaped facilities in the U.S. — in the states of Washington and Louisiana. Inside each detector, a laser beam shoots down two 2.5-mile-long (4-kilometer-long) tunnels, bouncing off pristine mirrors at each end. When a gravitational wave passes through Earth, it subtly stretches one tunnel and squeezes the other. That microscopic shift alters the laser beams ever so slightly, producing a tiny flicker of light that alerts scientists to a distant cosmic event.

Because these cosmic signals are inconceivably small, preserving every single photon is crucial. To accomplish this, LIGO relies on mirrors polished to reflect 99.9999%t of the laser light that strikes them, ranking them among the purest optical components ever built.

Yet even these near-perfect mirrors have had one unavoidable flaw. The mirrors still absorb a tiny fraction of that intense laser light. That energy turns into heat, warping the mirror's surface by just a few nanometers, enough to distort the laser beam and reduce the observatory's overall sensitivity.

Physicists already knew they could counteract these distortions by applying targeted heat to the back of the mirrors. The difficult part was measuring the distortions accurately enough such that the correcting heat could be applied with exact precision.

The new technique uses infrared thermal images and existing computer models to reconstruct a map of distortions across the mirror's surface.

"You can think of it like taking an infrared picture of a car engine," Richardson said in the statement. "An engineer can look at the temperature pattern on the outside and infer what's happening inside the engine. We're doing the same thing with LIGO's mirrors."

And the technique isn't just a fix for LIGO. It is also expected to become part of the foundational design for Cosmic Explorer, a proposed next-generation U.S. gravitational-wave observatory targeted for the mid-2030s.

With 25-mile-long (40-km-long) arms — 10 times larger than LIGO's — Cosmic Explorer is already designed to detect gravitational wave events far beyond the reach of today's observatories. This new technique will only supercharge its ultimate reach.

"The goal for the next generation of gravitational-wave detectors is to achieve about 10 times the sensitivity of today's instruments," Richardson said in the statement. "One of the key obstacles to achieving that is reducing the fundamental quantum mechanical noise that limits the precision of the measurements."

The technique is described in a paper published July 16 in Classical and Quantum Gravity.

Paleontologists now know that many of the dinosaurs didn't disappear but instead evolved into modern birds, and new research suggests that "cosmic dinosaurs" observed by the James Webb Space Telescope (JWST) didn't go extinct either. Rather, they may have evolved into familiar sights in the modern universe: vast conglomerations of densely packed stars called "globular clusters."

Little Red Dots became quite the puzzle for astronomers in 2022, when the JWST began to routinely spot them in abundance around 600 million years after the Big Bang. That is because these objects seemingly disappear before the cosmos gets to around 2 billion years old.

Astronomers have proposed many different explanations for Little Red Dots, including the suggestion that they could be "black hole stars," or black holes wrapped in vast shrouds of dense gas and dust. This team theorizes that a forming globular cluster with a supermassive star, a hypothetical short-lived stellar body with between 1,000 and 10,000 times the mass of the sun, would also look a lot like a Little Red Dot at its heart.

"These may not be just a strange new JWST population with no connection to the universe around us today," team leader John Chisholm of the University of Texas Austin said in a statement. "Instead, Little Red Dots may persist past the early universe, evolving into something relatively familiar.

"Little Red Dots could be galaxies, they could involve black holes, or they could be something even more unexpected. Our work shows that forming globular clusters with supermassive stars should be part of that conversation."

An unfamiliar side to a familar sight

Globular clusters are generally seen in large galaxies and are densely packed with up to many millions of ancient stars. Our galaxy, the Milky Way, is host to at least 150 globular clusters, and though familiar, astronomers still aren't quite sure how they form.

"We usually see them [globular clusters] after billions of years of evolution, at a time when their massive stars are gone, their gas has been cleared out, and dynamical processes have changed their masses and structures," team member Danielle Berg of UT Austin said in the statement. "That makes it very hard to reconstruct the original conditions they formed in."

It is thought that the stars in globular clusters all formed at the same time in the early universe. However, at this time the cosmos should only have had hydrogen, helium and a smattering of heavier elements (which astronomers call "metals") available for star construction. Yet, many stars in globular clusters are strangely abundant in helium and metals like nitrogen, sodium and aluminum, while lacking the expected levels of carbon, oxygen and magnesium.

"This specific pattern indicates nuclear fusion at very high temperatures, much higher than in the cores of even massive normal stars," team member Mike Boylan-Kolchin of UT Austin said in the statement. "A supermassive star is precisely the kind of environment that could produce this combination."

Supermassive stars capable of generating this kind of heat would form in the dense environments of early globular clusters in which stellar collisions and mergers would be expected to occur over and over again. The resultant supermassive stars would be short-lived, lasting just around 1 million years (remember the sun is middle-aged at 4.6 billion years old) — but this would be sufficient time to forge the elements needed to explain the peculiar chemistry of globular clusters.

When these supermassive stars die in supernova explosions, the elements they forged would be blasted out to become the building blocks of the next generation of stars. This would provide the stars of modern globular clusters with their unusual chemical fingerprints.

"In our model, the supermassive star that helps make the object look like a Little Red Dot would live for only a short time," Chisholm continued. "Once that star dies, the object may no longer look like a Little Red Dot, even if the cluster itself survives billions of years."

Strange chemistry isn't the only thing linking early globular clusters with Little Red Dots, however. Not only does the team propose that the distribution of Little Red Dots in the early universe matches the distribution of modern globular clusters, but they also say models of Little Red Dot evolution show that their estimated masses could easily lead to the masses of globular clusters seen in the recent universe.

There is also the issue of timing. Little Red Dots appear around 600 million years after the Big Bang, and that is also the time that scientists estimate that globular clusters would have begun to form.

"There's no single smoking gun at this point that says Little Red Dots are globular clusters, but it would explain a lot of diverse and surprising observations," said Boylan-Kolchin.

This study is currently available to view as a pre-print on the paper repository arXiv.

The launch of NASA's next super telescope, the Nancy Grace Roman Space Telescope (Roman), may mean there is nowhere left for violent black holes to hide.

In fact, these cosmic cannibals may not even be able to hide from Roman at "cosmic noon," a period of the universe's history that occurred around 11 billion to 12 billion years ago. The study of these gory stellar events so early in the history of the universe could help reveal how supermassive black holes grew so big, so rapidly.

Occurrences of black holes ripping apart stars are called tidal disruption events (TDEs), and they happen when an unfortunate star's orbit brings it too close to the immense gravitational influence of a supermassive black hole. This simultaneously squashes and squeezes the star in a process called "spaghettification," with plasma pasta wrapping around the black hole and being fed gradually to it.

Because supermassive black holes are wrapped in a one-way, light-trapping boundary called an event horizon, the only way to study them is when they are actively consuming surrounding matter. Such matter swirls around them in what are known as accretion disks.

However, lighter supermassive black holes aren't ravenous feeders, making them harder to investigate. That is, until a star gets too close and is shredded in an incredibly bright TDE that can outshine the combined light of every star in the supermassive black hole's host galaxy. TDEs are more common to supermassive black holes with masses of about 100,000 to 100 million suns, because supermassive black holes with masses over 1 billion solar masses tend to immediately swallow their stellar snacks.

Previous research has suggested TDEs wouldn't be common in the early universe, because the first supermassive black holes wouldn't even have a mass of 100,000 times that of the sun and thus wouldn't shred stars. However, a new study has reassessed the frequency of TDEs around 1 billion to 2 billion years after the Big Bang, finding they could be more common than previously estimated. Especially during the crowded conditions found during cosmic noon.

Set to launch on Aug. 30, 2026, scientists are hoping Roman's High-Latitude Time-Domain Survey, which will repeatedly revisit a region of the sky equivalent to 90 full moons, will be a powerful tool in the hunt for TDEs in the early universe and their subsequent study. This team estimated that Rubin will detect thousands to tens of thousands of TDEs each year, with 100s dating back to cosmic noon.

"The Roman Space Telescope is going to be transformative for transient science [transients are astronomical events that light up the sky then fade away]," research team leader Mitchell Karmen of the Johns Hopkins University said in a statement. "Thanks to Roman's high sensitivity, we can find multiple tidal disruption events out to greater distances and earlier cosmic times than ever before."

This means Roman is ideally poised to solve a puzzle that has developed since its predecessor, the James Webb Space Telescope (JWST), began beaming data back to Earth in July 2022.

How could early TDEs solve the puzzle of black hole growth

Supermassive black holes with masses equivalent to millions or even billions of suns are found at the hearts of all large galaxies. When they are seen in the relatively local universe, that isn't so problematic; they have had plenty of time to grow via mergers and feeding.

However, the JWST has been routinely spotting supermassive black holes prior to the universe being even 1 billion years old. That is troubling because these early black holes should have had to undergo at least 1 billion years of mergers and gluttonous feeding to reach supermassive status. Scientists have two prevailing theories as to how this growth may have happened.

The first suggests supermassive black holes grow from "light seeds," beginning with black holes with masses just a few hundred times that of the sun that are born from the death and collapse of massive stars.

Such black holes might weigh up to a few hundred times the mass of the sun. These black holes would then merge over time, as well as consume surrounding gas at an incredible rate that facilitates rapid growth. For this theory to be the right one, every young galaxy would have to harbor a massive black hole at its center.

The second theory suggests early supermassive black holes grew from "heavy seeds" created directly from the collapse of vast clouds of primordial gas and dust. This would allow rapid growth because black holes could begin the whole merger and feeding process before the first stars lived and died.

Should this be the correct pathway, however, the fact that collapse events would be rare would make massive black holes at the heart of cosmic noon galaxies less common.

Because TDEs are common to less massive supermassive black holes, counting their occurrence at cosmic noon could give an indication of the masses of black holes during that epoch — the key to determining between heavy seeds and light seeds.

"Tidal disruption events help us probe the population of light supermassive black holes, which can help us discriminate between these models," Karmen said.

"Just by counting the number of TDEs as a function of redshift [a measure of cosmic distance], you can put meaningful constraints on the population of million-solar-mass black holes. Roman will be transformative in that it can probe tidal disruption events out to greater distances, so you can look at how the rate of TDEs evolves over time," team member Suvi Gezari, an associate professor of astronomy at the University of Maryland, said. “Just like the JWST has transformed our understanding of distant, high-redshift [very distant] galaxies, Roman is poised to transform our understanding of high-redshift transients."

The team's research was published on July 14 in The Astrophysical Journal.

Thanks to the James Webb Space Telescope (JWST), astronomers have been given a glimpse of the mechanisms that supermassive black holes use to feed themselves. The observations could help scientists discover how supermassive black holes with masses millions, often even billions, of times that of the sun grew so fast so soon after the Big Bang.

While all large galaxies have supermassive black holes at their hearts, some are slumbering giants, consuming little surrounding gas and dust, while others are ravenously feeding and acting as the engines of bright central galactic regions called active galactic nuclei (AGN). These feeding black holes also blast matter from their poles in jets that can drive gas and dust — the raw material needed for star formation — out of their host galaxies, thus cutting off star birth and effectively "killing" these galaxies.

Plus, the powerful cosmic titans get really puzzling when astronomers using the JWST spot them before the universe was even 1 billion years old. That's because the mechanisms by which black holes devour matter to grow and then merge to create even more massive black holes should take at least 1 billion years to achieve supermassive status. This is even more confusing because theories also say the most ravenously feeding black holes (and thus the fastest growing) should also push the matter they use for this growth away, in effect putting themselves on a diet. So, with all this in mind, how did supermassive black holes grow so rapidly in the early universe?

One explanation suggests supermassive black holes push away gas, starving themselves as predicted, but also that this matter eventually cools and falls back to the black hole. That would allow for another period of feeding and thus growth.

This explanation further suggests that as this gas cools down, it forms "streamers," or filaments, of gas just a few hundred light-years wide but which stretch thousands of light-years long. These would fall back to the center of the galaxy and form a swirling disk around its incumbent black hole, once again feeding it and triggering a new period of growth. This would then restart the jets from the black hole, which would again cut off the cosmic titan's food supply, allowing the whole process to begin once more.

The process would in essence be a self-regulating cycle of feasting followed by fasting. However, the connection between these filaments and supermassive black holes has been elusive, meaning this mechanism has resisted confirmation.

"What JWST is revealing is that black holes may be the ultimate cosmic recyclers," team leader Julie Hlavacek-Larrondo of the Université de Montréal said in a statement. "They release enormous amounts of energy that heat their surroundings, yet that same gas can later cool into thin filaments that fall back inward and feed the black hole again. We are finally seeing this self-sustaining cycle in action."

A dieting supermassive black hole

To solve the mystery of feasting black holes, the JWST turned its attention to a relatively close AGN situated at the heart of the central galaxy of the Centaurus Cluster, NGC 4696, located just 145 million light-years from Earth.

The Hubble Space Telescope previously studied this galaxy, uncovering a strange, hook-shaped swirl of gas near the central supermassive black hole of NGC 4696.

The JWST followed up this discovery by producing a detailed map of gas flowing at the heart of the galaxy. This revealed the hook-shaped feature is around 800 light-years wide and is composed of gas moving at incredible speeds of around 1.3 million miles per hour (600 kilometers per second).

More excitingly, the swirl of gas appears to be connected to a vast filament of material falling in toward the central supermassive black hole.

The team tested the JWST observations against a computer simulation, finding gas in the infalling filament scenario would indeed take a shape similar to that seen in NGC 4696.

"JWST is now showing us the final link of this closed loop," team member Helen Russell of the School of Physics and Astronomy at the University of Nottingham in the U.K. said in the statement. "The vast filamentary network of gas flows ultimately funnels gas down to a disk that fuels the black hole."

The team's research was published on Wednesday (July 16) in the Astrophysical Journal Letters.

There may be an easier way to describe how black holes "leak" energy than the theory Stephen Hawking proposed — and the newly suggested process is similar to how we describe a boiling pot of water. This simple (well, relatively simple) description could be used to model black holes in many situations such as during their formation, mergers with other black holes, eventual evaporation and even explosive death.

In the 1970s, legendary theoretical physicist Stephen Hawking wrote a letter to the journal Nature entitled "Black hole explosions?" explaining how these objects may leak thermal radiation, evaporate and eventually implode at the end of their lives. This radiation eventually became known as Hawking radiation.

But in new research, scientists have suggested an alternative to Hawking radiation. It involves describing the increase in disorder, or entropy, of black holes. Boiling water, as an example, is also often described based on its increase in entropy. For black holes, this measure of entropy is connected to characteristics like spin and energy, which means it could be used to understand how these cosmic titans respond to different events.

"Hawking's laws of black hole mechanics provided a satisfying connection between extreme and ordinary physics and have been the paradigm for 50 years, but they have a serious limitation," team leader Abhay Ashtekar of the Eberly College of Science at Penn State University said in a statement. "They were formulated for black holes at equilibrium — or unchanging over time — but black holes are constantly changing; they form, merge, and eventually evaporate. We wanted to find a way to overcome this limitation and extend the laws to black holes that are out of equilibrium."

Black holes, Einstein and Hawking

To investigate the origins of black holes, one has to go back to history's most famous physicist (sorry Hawking, you're number two), Albert Einstein.

In 1915, Einstein revealed his theory of gravity, general relativity. One consequence of the equations underpinning that theory was the possibility of a singularity, a point at which the equations of general relativity go to infinity. This represents the heart of a black hole.

Another consequence of the general relativity equations is a region of space around this singularity at which gravity is so extreme that the escape velocity of the area increases to a value greater than the speed of light. That region is the light-trapping outer boundary of the black hole known as the event horizon, which prevents us from ever seeing the singularity at the heart of the black hole or receiving information from it. In fact, until Hawking's work in 1974, this is why it was proposed that nothing at all can escape a black hole.

"The laws of black hole mechanics came directly from Einstein's equations," team member Daniel E. Paraizo, a graduate student in physics at Penn State, said. "Because you cannot see into a black hole, it seemed that there could be an infinite number of ways to make a black hole, making their entropy infinite as well. They were also thought to only absorb energy and never radiate, so their temperature was zero."

However, the advent of Hawking radiation somewhat changed this paradigm. By suggesting that black holes actually radiate thermal energy, Hawking redefined them in such a way that suddenly the laws of thermodynamics could be applied to black holes.

"This changed the thinking about the thermodynamic properties of black holes from a sort of mathematical concept described by equations, to being more of a physical reality," Paraizo said. "This opened the door to finding analogies in black holes of entropy and temperature used in thermodynamics."

In Hawking's recipe for black holes, the area of the event horizon is proportional to its temperature and entropy, and is inversely proportional to its mass and its spin.

"There is a problem, though," team member Jonathan Shu, also from Penn State, said in the statement. "These analogies only really work for a black hole that is at equilibrium. In dynamic situations, event horizons can form and grow in what we call flat regions of space-time, where nothing is happening."

Shu added that a consequence of this is the properties of black holes cannot be determined just by the local physics of the black hole. Instead, determining the properties of black holes relies on the prediction of events that may or may not happen in the future.

"Therefore, the area of event horizons cannot be a measure of the physical entropy of dynamical black holes," Shu argues. "If we want to understand black holes that are growing, evaporating and merging, we need a viable alternative."

For the team, this meant replacing the event horizon of a black hole with something they call a "dynamical horizon," already used when scientists simulate black holes. Now, the first law of thermodynamics — which states the energy of a closed system cannot be created or destroyed but rather can only change forms — can be applied to black holes even when they are involved in dynamic acts. It also means black holes are subject to the second law of thermodynamics, which says the total entropy of an isolated system will always increase over time, during their birth, merger and death.

"This allows us to extend the first and second laws of thermodynamics to black holes that are not at equilibrium, thereby overcoming the limitations of the paradigm that has been used for over half a century," Ashtekar said. "We can apply these generalized laws to better understand evaporating black holes in quantum theory and black hole mergers."

The team's research was published in June in the journal Physical Review Letters.

The first of 10,000 missing black holes in the Omega Centauri globular cluster has been found thanks to teamwork by the Hubble and James Webb space telescopes.

The two observatories discovered the black hole after watching a star orbiting around something massive but dark, and which therefore could not be seen. The Hubble data ran from 2003 to 2023, and the James Webb Space Telescope picked up after that to help refine the measurements.

Astronomers used the space telescopes to focus on a particular star in a binary system that appeared to be home to another, dark object called oMEGACat BH-2. Previous studies had suggested that the dark object was a neutron star. However, the new results are conclusive: the object has a mass 4.46 times that of the sun. This is too massive to be a neutron star, so it must therefore be a black hole.

Omega Centauri is the most massive of our Milky Way galaxy's globular clusters. It is so massive that astronomers suspect that it is actually the core of a dwarf galaxy that has lost most of its stars to the Milky Way's gravitational cannibalism, which over the aeons has torn strips from Omega Centauri. Even so, Omega Centauri still contains about 10 million stars, collectively located 18,000 light-years from Earth.

In 2024, astronomers using the Hubble Space Telescope found clinching evidence that an intermediate-mass black hole – one that has a mass about 8,200 times that of our sun – lurks at the center of Omega Centauri, strengthening its claim of being the remnant of a dwarf galaxy, since galaxies harbor black holes at their center but star clusters typically do not.

However, alongside this intermediate-mass black hole should be about 10,000 other stellar-mass black holes born from the supernova explosions of massive stars. Searches have focused on binary systems where a star orbits a compact object, but until now astronomers had drawn a blank.

Now, a team led by Matthew Whitaker of the University of Utah in Salt Lake City have come along to save the day by diligently sifting through 20 years of Hubble observations, plus additional supporting views from the JWST, to uncover a stellar-mass black hole in Omega Centauri for the first time.

Whitaker's team used a technique called astrometry, which is the measurement of the changing positions of stars as they move through space. Although the black hole itself is dark, it is orbited by a normal star with a mass 78% that of our sun. Thanks to the unprecedented vision of Hubble and the JWST, Whitaker and his colleagues were able to track the motion of this star around the black hole.

It turns out that the star is on a 94-year-long orbit around the black hole, which is the widest separation of a binary composed of a stellar-mass black hole and star ever found. Over that 20-year-period, Hubble saw less than a quarter of the star's total orbit, but it coincided with the star's closest approach to the black hole, during which the star moved faster.

Based on this motion, Whitaker's team were able to measure the strength of the black hole's gravitational field acting on the star, and from that calculate the mass of the black hole.

"The precision of these measurements is incredible, down to a fraction of a pixel on Hubble and Webb's detectors," said Whitaker in a statement. "It would not have been possible to find this black hole without these two space telescopes."

Given how wide the orbit of the star is around the black hole, the likelihood is that the black hole's gravity captured the star when it passed close. This is a state of affairs that will not last forever; within another billion years, encounters with other stars in the crowded environs of the cluster will probably pluck the black hole's companion away.

The mass of oMEGACat BH-2 does seem unusual, however, in the sense that it is lower than expected. The mass of oMEGACat BH-2 exists in a void that has only become apparent during the past eleven years of gravitational wave detections. These gravitational waves are produced by the mergers of stellar-mass black holes, but black holes with masses between 2.5 times the mass of our sun (the theoretical limit for neutron stars) and five solar masses are conspicuous by their absence in the gravitational-wave events. Yet here is oMEGACat BH-2, sitting within that mass gap.

"It's important to understand black hole populations in globular clusters because there's uncertainty about their physics and formation," said Anil Seth of the University of Utah.

"More specifically, understanding the process of forming black holes and then dynamically forming binaries is vital, because it affects our ability to interpret and understand gravitational-wave events. Environments like Omega Centauri are the primary places where we think binaries are merging and creating these waves."

In particular, the stars of Omega Centauri are more primitive than our sun, chemically speaking, with fewer elements heavier than hydrogen and helium. Which types of massive stars produce black holes when they explode as supernovas is still an area of active research, but oMEGACat BH-2 adds another complication to the mix in that its progenitor star contained few heavy elements.

"We need to figure out how that happens," said Seth.

So that's one down, and 9,999 or thereabouts to go. Whitaker's team continue to use Hubble and JWST data to find more stellar-mass black holes in Omega Centauri, but he also highlights the potential of NASA's Nancy Grace Roman Space Telescope to find black-hole binary systems in our Milky Way galaxy at least when the telescope launches later this year.

"Roman … will image the crowded galactic bulge, including the galactic center, very regularly with Hubble-like resolution and with a much wider field of view," said Whitaker. "We're hoping we'll be able to find black hole binary systems like this one because of the regular cadence of Roman's observations."

The details regarding oMEGACat BH-2 are described in a paper published on July 13 in The Astrophysical Journal Letters.

A supermassive black hole at the heart of a nearby galaxy is behaving similarly to black holes that existed just after the Big Bang, voraciously feeding on copious amounts of matter. The relatively close cosmic titan could therefore provide insight into the much more distant universe.

Indeed, the intense accretion behavior demonstrated by the supermassive black hole, which sits at the center of the galaxy SDSS J110546.07+145202.4 located 1.8 billion light-years away, is something scientists have only ever seen in the earliest supermassive black holes.

SDSS J110546.07+145202.4 has been shining brightly in radio waves for many years, and these waves were the smoking gun that pointed to the feeding habits of the galaxy's central black hole.

"Such high-energy events can provide astronomers with a wealth of insights," Kovi Rose from the University of Sydney’s Sydney Institute for Astronomy said in the statement. "By observing these jets and outbursts, we can study the physical processes in some of the most extreme environments in the universe."

Even the hungriest black holes are messy eaters

All large galaxies have a supermassive black hole at their heart with masses of millions or even billions of times that of the sun. However, not all supermassive black holes accrete vast amounts of matter.

For example, the supermassive black hole at the heart of our galaxy, the Milky Way, Sagittarius A*, consumes so little gas and dust from its surroundings that, were it a human being, it would be existing on a diet of one grain of rice every million years. (That is one heck of a diet.)

When black holes are surrounded by copious amounts of gas and dust, their immense gravitational influence causes this material, in a flattened swirling cloud called an accretion disk, to glow brightly across the electromagnetic spectrum, from low-energy radio waves to high-energy X-rays.

Additionally, supermassive black holes are notoriously messy eaters, meaning some of the matter in accretion disks is channeled to the poles of the black hole, from where it is blasted out as jets of plasma traveling at speeds approaching the speed of light. These jets too are responsible for bright emissions of electromagnetic radiation.

Radio signals from the spiral galaxy SDSS J110546.07+145202.4 underwent a 20-fold increase in radio brightness over a short period, increasing to around 10 quadrillion times the intensity of the radio brightness of the sun. This happened around 8 years ago, and the galaxy has yet to show any sign of dimming.

"We are dealing with the prototype of a new class of galaxies that undergo rapid changes in radio emission," team member Phil Edwards from CSIRO, Australia’s national science agency, said.

Team leader Stefanie Komossa of the Max-Planck-Institute for Extraterrestrial Physics in Garching, Germany, added: "Luminous radio radiation from rapidly growing, lightweight black holes is rare to begin with. Their transition into a long-lasting, radio-bright state has never been observed before."

The source of this electromagnetic radiation is situated at the heart of SDSS J110546.07+145202.4, right by its central supermassive black hole. The team thinks the brightening of this galaxy began because the rate of matter falling into its supermassive black hole had increased, triggering the generation of plasma jets.

The increase in mass consumption of the supermassive black hole is leading to a level of growth that hasn't been seen in black holes outside of the early universe before. That means that SDSS J110546.07+145202.4 and its feasting supermassive black hole are set to be prime targets for astronomical investigations for some time to come, especially as proxies for ravenous black holes and rapidly growing early galaxies.

"With sensitive facilities like the incoming SKA telescopes, we'll be able to identify similar radio transients in future sky surveys," Komossa said. "This is crucial for filling the gaps in our understanding of the early universe."

The team's research was published in May in The Astrophysical Journal.

The universe is haunted by "cosmic ghosts" called neutrinos, and new research suggests they may be the "whispers" of stars that died in supernova explosions over the course of billions of years.

The discovery is an important step forward in our understanding of the life and death of stars and how they enrich their environments with metals, elements heavier than hydrogen and helium. It could also help better understand how black holes and neutron stars are born when massive stars die.

The second most common particles in the universe, neutrinos get their spooky nickname because they are chargeless and near-massless, so phantom-like that around 100 trillion neutrinos pass through you at nearly the speed of light every second, but over your entire life only one will interact with the atoms of your body, if you're lucky.

The newly suggested connection between neutrinos and a history of supernova blasts has emerged from the first detection of a flux of neutrinos called the Diffuse Supernova Neutrino Background (DSNB). It was detected by one of the world's largest neutrino detectors, the Super-Kamiokande, located 3,280 feet (1,000 meters) underground in Gifu Prefecture, Japan.

"Observing the world's first indication of the Diffuse Supernova Neutrino Background is a deeply meaningful achievement and has been a long-cherished goal since the beginning of the Super-Kamiokande project," Hiroyuki Sekiya of the University of Tokyo said in a statement.

Stars go out with a bang but continue with a whisper

Supernovas come in a range of types, but the ones this research concerns are so-called "core-collapse supernovas." These occur when stars much more massive than the sun reach the end of nucleosynthesis in their cores. When they are no longer able to fuse elements to create metals heavier than iron, the stars become unable to produce the outward energy that for millions of years has balanced them against the inward push of gravity.

Thus, with gravity the ultimate winner of this cosmic tug of war, the star's core collapses, sending violent shockwaves rippling outward into the outer stellar layers, which are ripped away. This leaves the core as a stellar remnant, either a neutron star or a black hole, initially surrounded by an expanding shell of supernova debris.

The energy from these events is carried away by particles of light (photons) spread across the electromagnetic spectrum, but also by neutrinos. Yet, despite the fact that supernovas have been erupting every second over the course of 13 billion years or so to produce the neutrinos that accumulate as the DSNB, this ghostly signal is still faint, a whisper rather than a shout.

To "hear" these cosmic whispers, the team behind this research analysed almost 14 years of data from Super-Kamiokande in the form of Cherenkov light generated when neutrinos interact with 50,000 tons of ultrapure water.

This revealed a signal of neutrinos in line with what would be expected from the DSNB. This signal still needs to be confirmed, but it is a strong indicator of the DSNB, the first humanity has ever had.

"We are already planning on incorporating ongoing observations at Super-Kamiokande together with its successor detector, Hyper-Kamiokande, to further improve sensitivity in future collaborative studies," said team member Yosuke Ashida,of Tohoku University.

The team's results were presented on June 25, 2026, at Neutrino 2026: XXXII International Conference on Neutrino Physics and Astrophysics, held at the University of California, Irvine, USA.

Using the European Space Agency's Euclid space telescope, astronomers have discovered a treasure trove of 31 black-hole-powered quasars in the early universe. The most impressive of these new discoveries is the most ancient and distant quasar ever seen, shining with the light of a trillion suns just 670 million years after the Big Bang.

Quasars occur when supermassive black holes with masses millions or even billions of times that of the sun are surrounded by swirling disks of matter called accretion disks. As accretion disks gradually feed these central cosmic titans, the immense gravity of the black holes generates intense friction, causing this matter to glow so brightly that their luminosity can exceed the combined light of every star in their host galaxies.

Despite this, quasars can still be difficult to spot at vast cosmic distances, with their light difficult to distinguish from the light of much more proximate stars. Thus, the hunt for the earliest quasars has been on for decades, with scientists hoping that the discovery of these bodies could help explain how supermassive black holes grew so rapidly so shortly after the Big Bang. Launched in 2023, Euclid has fulfilled its promise in its mission to discover early quasars, with this hitherto unprecedented haul of 31 of these black hole engines.

"These early quasars date back to the Universe's infancy," team leader Daming Yang of Leiden University in the Netherlands said in a statement. "By finding and studying them, we can better understand how these enormous systems formed and grew so quickly — one of the greatest mysteries in astrophysics."

Previously, astronomers took around a decade to discover the first ten or so quasars at distances like this, which makes it incredibly impressive that Euclid has managed to detect more than three times that many ancient black hole engines in just a single year of observations.

The tip of the iceberg

Thanks to this new treasure trove of quasars discovered when the 13.8 billion-year-old universe was merely 5% of its current age includes not just the brightest examples of these objects, but also some fainter quasars. That now means scientists can finally study these objects as a population.

"Euclid is a true game-changer," Yang continued. "Before, we could only find a handful of the very brightest ancient quasars, but Euclid lets us search far more efficiently across huge areas of sky to capture much fainter light. It’s a unique tool for quasar hunting."

Of the 31 new quasars, 12 existed when the universe was around 770 million years old, but the two that really stand out are the quasars designated EUCL J172902.75+641018.1 and EUCL J125308.55+705432.3, which are around 13 billion light-years away and existed just 670 million years after the Big Bang. That makes them the most ancient quasars ever documented.

"This finding more than doubles the number of quasars we know of that are so ancient," Antonio La Marca , a European Space Agency (ESA) Research Fellow on the Euclid team, said in the statement. "The Euclid team has taken a true 'census' of quasars at the dawn of the Universe for the first time. It's a big step towards understanding these fascinating objects on a more fundamental level."

The quasars date back to a period of the cosmos known as the epoch of reionization, which lasted from around 680 million years after the Big Bang to 1.1 billion years after the Big Bang. During this period, the universe's "dark ages" drew to a close with photons, particles of light, suddenly free to traverse the cosmos. Thus, these 31 quasars offer a unique opportunity to study this vital period in cosmic history.

"Ancient quasars are rare discoveries," ESA Euclid Project Scientist Valeria Pettorino said in the statement. "They're interesting in themselves, but also time machines that enable us to explore the early universe and understand how the first generation of galaxies came to be."

The 31 quasars were discovered as part of the Euclid Wide Survey, which will eventually cover around one-third of the total sky over Earth.

Scientists hope that this survey will shed light on the so-called "dark universe" comprised of two of the most pressing cosmic mysteries: dark energy, the puzzling force driving the acceleration of the expansion of the universe, and the nature of dark matter, the most abundant "stuff" in the cosmos which remains effectively invisible.

"Euclid's capabilities are unrivalled," Pettorino concluded. "The telescope combines a large area, depth, sharp imaging, and unique space-based infrared vision in a way that lets us pick out rare, extremely distant objects far more efficiently than before."

The team's research was published on Monday (July 6) in the journal Astronomy & Astrophysics.

Mysterious "little red dots" discovered in the early universe by the James Webb Space Telescope could harbor buried black holes that fire high-energy cosmic "ghost particles" through the cosmos.

Neutrinos are referred to as ghost particles because as chargeless and near-massless particles, hundreds of trillions of them stream through your body every second at nearly the speed of light. Plus, the source of high-energy neutrinos frequently detected on Earth is something of a mystery.

And another cosmic mystery is the existence of the "little red dots," which are galaxies that have been discovered by the James Webb Space Telescope (JWST). Though common around 600 million years after the Big Bang, these dots seem to disappear before the universe gets to 2 billion years old. Some researchers have theorized that these curious small galaxies could harbor black holes that are buried in thick shrouds of cosmic dust. If that is the case, then the dots could be a major contributor of high-energy neutrinos, linking these two mysteries.

Neutrinos are produced when other particles, such as protons, collide with particles of light, or photons, or with different sorts of matter. This usually occurs in gas-dense environments, but the ghost-like characteristics of neutrinos mean they have little trouble escaping into the universe at large.

Usually, the events that create high-energy neutrinos also give rise to high-energy photons called gamma-rays. However, neutrinos are so abundant as the second most common particles in the cosmos that if all sources of neutrinos also created gamma-rays, the gamma-ray background of our universe should be much greater than it actually is.

That means some sources of high-energy neutrinos must be located in environments from which gamma-rays can't readily escape — and that's where the little red dots enter the picture. These curious objects display very little emission associated with galactic jets or other outflows. This led this team to assume that the lack of these emissions, which should come in the form of X-rays and radio waves, is because the black holes and associated jets in Little Red Dots are buried in dense halos of dust and gas.

"In the scenario we considered, abundant photons and dense gas are expected to exist around the central black hole in a little red dot, which may allow such collisions to occur efficiently," team leader Riku Kuze of Kyoto University said in a statement.

Kuze and colleagues estimated the contribution that the little red dots could add to the universe's neutrino background. This revealed that, should particle acceleration be occurring in the buried black holes within the dots, these environments could produce high-energy neutrinos to contribute a significant fraction of the high-energy neutrino background observed on Earth. This would be while also suppressing gamma-ray escape.

"Although it is difficult to observe the individual objects directly, we believe this study is significant because it is the first to demonstrate that, given their abundance, these little red galaxies could account for a part of the observed high-energy neutrinos," said Kuze.

Neutrinos come in more than one type, or flavor; thus, the next step for the team will be to determine the ratio of neutrino flavors generated by buried black holes in the little red dots and to determine if this matches cosmic abundances witnessed.

The team's research was published in the journal Physical Review D.

The loudest crash of gravitational waves ever heard has offered us insight into event horizons, the boundaries beyond which nothing can escape the grips of black holes.

The gravitational wave signal GW250114 was picked up in January 2025 by LIGO (Laser Interferometer Gravitational-Wave Observatory), Virgo, and KAGRA ( Kamioka Gravitational Wave Detector). The signal was created when two black holes with around 32 times the mass of the sun collided and set the very fabric of space rippling.

Now, a team of researchers assessed this signal and found a feature in the gravitational waves represents the collective event horizon of the involved black holes at the very moment of that collision.

"We measured the last sound the black holes made when they crashed. Hidden within that signal is a small component, called direct waves, that had not previously been well understood," research co-leader Neil Lu, from the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav), said in a statement. "Our new analysis allows us to decipher this component and extract unique information from close to the event horizon."

The team's research presents the intriguing possibility that scientists could use gravitational waves to study these mysterious black hole boundaries.

Event horizons and the point of no return

The concept of an event horizon first emerged through solutions to the equations of Albert Einstein's 1915 theory of gravity, general relativity. These solutions were developed by Karl Schwarzschild while serving with the German army on the Eastern Front in the First World War.

Schwarzschild found a point around a body with mass at which the escape velocity, the speed needed to escape the gravitational grip of that body, exceeds the speed of light. Also known as the Schwarzschild radius, the size of that boundary depends on the mass of the body. So the Schwarzschild radius for the sun would be about 1.86 miles (3 kilometers) from its center of mass; for the Earth, it would be just 0.35 inches (9 millimeters) from our planet's center of mass. That's the case with all planets and stars; the Schwarzschild radius is well within the bodies of those objects.

However, for a black hole, the Schwarzschild radius is far from the center of mass, acting as a light-trapping outer boundary: the event horizon. To escape the gravitational grip of a black hole from this point, matter would have to accelerate to a speed faster than the speed of light, which Einstein's theory of special relativity tells us would require infinite energy. Nothing in the universe travels faster than light; thus, nothing escapes the event horizon.

To understand why that shrouds a black hole in mystery, consider how no signal can travel faster than light. That means the event horizon is a one-way barrier for information. A black hole can swallow it, but the event horizon prevents it from spitting information out. We can never observe the interior of a black hole.

It's little wonder scientists are so keen to study event horizons and what happens there. They don't only want to understand the physics of matter engaged on a one-way trip into the maw of a black hole, but the effect on the very fabric of space itself these cosmic titans have.

The immense gravitational influence of black holes means that, as they spin, they drag the very fabric of space along with them, a phenomenon called "frame-dragging" or the Lense-Thirring effect. This introduces another rule about event horizons — not only does nothing escape this boundary, nothing there sits still either. This research brings scientists one step closer to understanding those rules in greater detail than ever before.

"We studied GW250114, the loudest binary black hole signal observed to date, about three times louder than the first gravitational-wave signal detected a decade ago," team co-leader Ling Sun of OzGrav said. "Our analysis shows that this exceptionally loud signal can be used as a powerful probe of the remnant black hole's horizon, allowing us to measure its two fundamental properties: rotation frequency and surface gravity."

The results could also shed more light on the behavior of gravity in the most extreme environment in the universe, at the very edge of a black hole.

"These measurements mark a first step towards future tests of general relativity with direct waves," Lu said.

The research was published on Wednesday (June 24) in the journal Nature.

Astronomers have used a technique called echo mapping to detect hints that supermassive black holes, such as the cosmic titan at the heart of the Milky Way, known as Sagittarius A* (Sgr A*), are surrounded by dense clouds and clusters of dark matter. The research could teach us more about this mysterious substance and the environments around supermassive black holes.

Dark matter is the universe's most mysterious stuff, outweighing ordinary matter in the cosmos by a ratio of five to one — but remaining effectively invisible because it doesn't interact with electromagnetic radiation, including the light we use to see. The only way scientists can even infer the presence of dark matter is via its interaction with gravity, and the impact that this interaction has on objects made of traditional matter like stars. For instance, the gravitational effect of dark matter allows stars at the edges of galaxies to whip around at much greater speeds while not flying loose than the visible matter of those galaxies would allow.

This team decided to test the gravitational influence of dark matter at the hearts of galaxies, environments dominated by supermassive black holes which can have masses millions or even billions of times that of the sun. Ordinary matter around these supermassive black holes is often very visible, especially when spiraling into the maw of one of these cosmic titans from a flattened cloud called an accretion disk. This is because the gravitational influence of those black holes generates immense amounts of friction, causing them to grow brightly. That wouldn't work for dark matter; it can't feel friction because it doesn't interact with itself or with ordinary matter, and it can't glow because it doesn't absorb or emit light.

Clearly, dark matter can't be spotted around supermassive black holes even using the most advanced telescopes such as the Event Horizon Telescope (EHT), which has captured glowing rings of material around Sgr A* and around a more distant supermassive black hole that rules the heart of the galaxy Messier 87 (M87).

While discussing the problem of detecting dark matter around supermassive black holes, Mayank Sharma, a physics graduate student at Virginia Polytechnic Institute and State University (Virginia Tech), hit on an interesting solution.

"We could actually test this prediction using a technique in astronomy, which allows you to measure the distance to the surrounding gas by looking for echoes of light," Sharma said in a statement. The technique Sharma refers to is "reverberation mapping," and it has become a trusted method of determining the mass of black holes.

Echoes of dark matter

Reverberation mapping is based upon the fact that as matter falls into a black hole, it releases a burst of energy that causes the accretion disk it comes from to pulse. This pulse of light travels from the accretion disk to gas in the wider environment of the black hole. This gas absorbs that light and also pulses, with this secondary pulse serving as an echo of the first.

Because we know the speed of light, when astronomers see the first pulse of light and then its echo, they can use the time between pulses to estimate the distance between the black hole and the gas on the outskirts of its environment. The size of a black hole and the distance between it and outer gas clouds can be used to determine its mass, and could also be used to determine the mass of dark matter clustered around it.

The team applied their method to 14 different galaxies, finding in five cases that mass increases moving away from the central black hole in a way that couldn't be accounted for by visible matter alone. Despite the early success of this research, it far from proves that supermassive black holes are indeed gathering places for dark matter. The team's findings do point an interesting way forward for the investigation into the universe's most mysterious substance and its most mysterious regions.

"These galaxies are definitely showing a hint that there is extra material that cannot be explained by just the supermassive black hole," Sharma said. "The prospects are exciting."

The team's research was published in the journal Physical Review D.

Supermassive black holes are notoriously messy when devouring a star, but they can also linger over their meals, letting out massive radio "burps" months or even years after their cosmic feast appears finished.

Now, scientists tracking these events have found there is no one-size-fits-all model for how black holes digest stellar material. Speaking Monday (June 15) at the 248th meeting of the American Astronomical Society in California, Kate Alexander, an astronomer at the University of Arizona who has been studying these events, said the behavior depends instead on their shifting dietary phases.

"Sometimes, after it seems like they are done eating, they may get indigestion and they may let out a large radio 'burp,'" Alexander said during a press conference on Monday. "These late-time radio burps can appear when the black hole eats too fast or eats too slowly, so you should always eat the right speed if you want to avoid indigestion."

Her recent research focuses on Tidal Disruption Events, or TDEs, which are cosmic catastrophes that occur when an unlucky star wanders too close to a supermassive black hole. As the star nears the behemoth, intense gravitational fields shred it into a spaghetti-like stream of gas debris in a process known as "spaghettification."

Because these events are rare, occurring roughly once every 100,000 years in any given galaxy, astronomers must monitor a large number of galaxies just to spot them. Historically, targeted radio follow-up of these disruptions ceased if no emission was detected within the first year or so, leaving their long-term behavior unstudied.

"When we first started looking at them, we just stopped looking," she said. "But, it turns out that we should have kept looking, because this is often when some of the most really interesting things are happening."

Over the past six years, astronomers have been using the Karl G. Jansky Very Large Array (VLA) telescope in New Mexico to conduct the first large-scale, systematic radio observations of several dozen nearby TDEs. A 2024 paper, by radio astronomer Yvette Cendes of the University of Oregon and co-authored by Alexander, first reported that roughly 40% of all TDEs are detected in radio months to years after the initial disruption, long after the visible light has dimmed.

Now, published this year in The Astrophysical Journal, the new study led by Alexander sets out to explain why these long-dormant systems reactivate. To solve the mystery, the researchers combed through decades of data, analyzing 91 TDE candidates discovered between 1990 and 2019 before narrowing their focus to a gold-standard sample of 31 events with comprehensive, multiwavelength tracking.

By blending VLA radio data with archival optical and ultraviolet observations, plus fresh follow-up X-ray measurements, the team mapped how much gas the black holes actually consumed at any given point in time. Matching that feeding timeline against the exact moments the radio flares emerged revealed precisely how fast the black holes were eating when they unleashed their outflows, Alexander explained during the press briefing.

The data revealed that these delayed flares ignite at two opposite extremes, either while the black hole is rapidly overgorging on gas, or after its feeding rate has slowed to a crawl. In both scenarios, a fraction of the incoming gas is flung outward instead of being fully consumed, the team found. This expelled material then slams into the gas surrounding the black hole, triggering particle-accelerating shock waves that produce the radio emissions — effectively creating the cosmic "burps."

This cosmic feeding mechanic operates identically across all scales, working the exact same way whether the black hole is a relative lightweight or a behemoth millions of times more massive than our sun, Alexander noted.

"For those of us who are astrophysicists," she said, "this is really cool because we are now starting to understand how physics operates in these very different mass regimes."

The team also found that TDEs destined to flare up later leave a distinct chemical fingerprint in their early optical spectra in the form of helium emission lines. This signature indicates that the star's shredded debris is taking its time settling into a tidy, ingestible disk around the black hole — virtually guaranteeing a delayed case of cosmic indigestion, said Alexander.

"These are the black holes that are having longer lasting meals," she said.

Based on these findings, the team suggests that a window of two to six years post-discovery is the most productive timeframe to hunt for these late-rising radio signals.

Ultimately, the team says the predictive chemical blueprint could serve as an invaluable screening tool. By filtering out the quiet eaters early on, astronomers can maximize highly competitive telescope time, focusing precious resources on the black holes most likely to put on a late-stage show.

Astronomers using NASA's Chandra X-ray spacecraft have obtained the most detailed image yet of the jet erupting from the supermassive black hole at the heart of the galaxy Messier 87 (M87).

If this black hole sounds familiar, that is because it made history in 2019 when it was revealed as the first black hole to be imaged by humanity.

M87* is located around 55 million light-years from Earth and is ravenously feeding on infalling gas and dust. As it does so, matter is channeled to the poles of this black hole, which has a mass 6.5 billion times that of the sun. This matter is blasted out at speeds approaching the speed of light as powerful jets that stretch out for thousands of light-years.

Jets of M87* have been imaged before in other wavelengths of light, such as optical light and infrared, but this is our most detailed look at these jets in X-rays. And the X-rays revealed a complex flow of material through the jets that's more dynamic than previously seen.

"We could already see changes in the jet, but never with this level of detail in X-rays," Camille Poitras, a Ph.D. student in the Faculty of Science and Engineering at Laval University and lead of the study, said in a statement. "Structures that previously appeared blended together can now be distinguished, allowing us to better follow the jet's evolution over more than a decade of observations."

Some structures in the jets appeared to be moving at speeds five times faster than the speed of light. Of course, that isn't possible; according to Albert Einstein's theory of special relativity, nothing with mass can move at the speed of light or faster. This so-called superluminal motion isn't a universe-breaking discovery, but rather an optical illusion created when matter moves at near-light speed directly toward Earth.

The Chandra observations of the jet of M87* are a major step forward in understanding the physics of these outflows and how the particles that comprise them are accelerated to such high speeds and great energies. Additionally, because these jets are how supermassive black holes pour energy back into their surroundings, the observations could also help build a better picture of how these cosmic titans influence the evolution of their home galaxies.

"These results demonstrate how uniquely powerful Chandra remains for tracking the evolution of extreme phenomena over long timescales," team member Gerrit Schellenberger, an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian (CfA), said in the statement. "They help us better understand how energy released near a supermassive black hole is carried through its jet and deposited into the surrounding galaxy."

The team's research was presented at the 248th meeting of the American Astronomical Society. The study is also available as a preprint on arXiv.

A faraway fluctuating quasar has been seen dimming and brightening by an extraordinary amount, changes in luminosity equivalent to 2 trillion times the brightness of the sun . It is the first time that a flickering quasar has been seen in the early universe, this one dating back 12.9 billion years – just around 900 million years after the Big Bang.

Quasars are the extremely active supermassive black holes at the heart of some galaxies, furiously feeding on gas that is being shoveled towards their maw, and growing as a result of this voracious feeding. As the gas circles the black hole's event horizon – the point beyond which nothing can escape the black hole – it grows hot as a result of friction, leading to the gas shining brightly. Additionally, magnetic fields can whip away some of the charged particles in the gas, blasting them away from the supermassive black hole in the form of powerful and bright jets. As such, quasars are some of the brightest objects in the universe.

More than a million quasars have been found across the universe, but only around 200 of these have been found existing in the first billion years after the Big Bang. While most quasars flicker, they usually do so by relatively modest amounts, and such flickering had not been seen in a quasar in the first billion years of cosmic history, until now.

"People have known that quasars in the nearby universe can flicker," Gene Leung of the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology (MIT) Kavli Institute for Astrophysics and Space Research, said in a statement. "The flickering comes from fluctuations in the way the gas is being fed into the black hole, and how the quasar flickers tells us something about the structure of a black hole's accretion disk and the kind of 'bites' that the black hole is eating."

The quasar in question is pumping out energy equivalent to the luminosity of 12 trillion suns, and its light fluctuates by about 20%, or 2 trillion times the luminosity of our sun, a quite remarkable amount indicative of how fast this black hole is growing.

Even so, the quasar is so distant that it is still extremely faint, so detecting these huge fluctuations wasn't easy. Not only has the light traveled a long way for a long time, but the expansion of the universe has also stretched the wavelength of that light to longer, redder wavelengths, a phenomenon called "redshift."

Distant quasar flickers like a cosmic candle

Leung and his MIT colleague Anna-Christina Eilers led a team that found the elusive flickering quasar after searching the archives of NASA's now-defunct NEOWISE (Near-Earth Object Wide-field Infrared Survey Explorer) mission. NEOWISE scanned the whole sky for about 14 years, searching for hazardous asteroids, but also capturing a lot going on in the background sky.

The redshift of the quasar's light also lowered the frequency of the fluctuations. Flickering that might have taken place on timescales of days when the light left this quasar was redshifted to months by the time this light reached us. That is why NEOWISE's many years of data were invaluable.

"We saw the quasar flickering randomly over the 14-year period, much like a candle's flame flickers without a fixed pattern," said Leung.

The flickering of the quasar at different wavelengths is connected to variations in the temperature of the gas swirling around this black hole. The closer the gas is to the black hole, the hotter it is. From this, Leung's team could deduce that the gas had settled into a very flat, pancake-shaped accretion disk around the black hole.

For an older quasar, this wouldn't be a surprise, but for such a young quasar, it is potentially revelatory. That's because supermassive black holes grow messily, and the cloud of infalling gas around a young quasar existing only 850 million years after the Big Bang should still be quite puffy, like a thick, chaotic donut-shaped torus. The gas should only flatten into a pancake shape once the quasar has matured. In other words, this quasar appears older than its years.

"I think that what this suggests is that all the messy, very rapid growth phases that we expect all black holes to go through at some point happen very, very early on, before we see them as these very bright luminous quasars," said Eilers. "That's the picture that's emerging."

Astronomers are already gaining evidence that supermassive black holes can form faster than we realized from directly collapsing clouds of gas, as evidenced by the 'little red dots' being discovered by the James Webb Space Telescope (JWST) in the early universe. The discovery of a mature quasar that existed 12.9 billion years ago bolsters the emerging theory that supermassive black holes formed early and developed fast.

"This means something happened even earlier on that led these systems to look so mature," said Leung.

Now, Leung and Eilers hope to search for even older quasars (the oldest ever seen existed 13.2 billion years ago), perhaps with the JWST, to try and capture whatever happened to cause them to grow up so quickly.

In the meantime, their findings can be read in a paper published on Monday (8th June) in Nature Astronomy.

Astronomers using the James Webb Space Telescope may be close to solving the mystery of "little red dots" in the early universe. The team has studied one of these strange objects, designated GLIMPSE-17775, finding evidence it is a black hole star — a ravenously feeding, growing supermassive black hole cocooned in a dense cloud of partially ionised gas.

Little red dots first started to turn up when the James Webb Space Telescope (JWST) began sending data back to Earth in the summer of 2022. They were said by some scientists to have "broken cosmology" because they appear in large numbers around 600 million years after the Big Bang, but they appear to disappear before the universe reaches 2 billion years old. Several explanations for little red dots have been proposed, but one that has emerged as a frontrunner is the concept of black hole stars. If black hole stars exist, the little red dot disappearance would be the result of their intense, short-lived growth spurts that cause them to burn out — or, because the growing supermassive black holes at their centers eventually clear away the dense gas and dust obscuring them, changing their appearance as they evolve into more typical active galaxies.

The problem is, however, that astronomers have been unable to gather observational evidence that little red dots are indeed black hole stars. That was until the JWST imaged little red dot GLIMPSE-17775, seen as it was just 1.8 billion years after the Big Bang, while making observations of the gravitational lens galaxy cluster Abell S1063. This data represents the deepest spectrum of light from a little red dot collected to date and, according to this team, contains multiple lines of evidence pointing to a black hole star.

"I think part of the scientific community is converging on a singular picture — that little red dots can be explained by black hole star models. But none of the previous little red dots have all of the pieces of evidence in the same place," Vasily Kokorev at the University of Texas at Austin said in a statement. "With GLIMPSE-17775 we can test these models because of how deep and amazing this source's spectrum is."

Solving the little red dot puzzle with a hand from Einstein

The JWST caught a glimpse of GLIMPSE-17775 while searching for the first generation of stars in our universe, somewhat confusingly called "Population III" stars. The telescope searched for these particular stars in the galaxies that comprise galaxy cluster Abell S1063.

Separately, Abell S1063 is a gravitational lens, meaning its massive gravitational influence actually curves the fabric of space and time (united as a single, four-dimensional entity called spacetime). This, in turn, means an object "behind" the galaxy cluster that's emitting light toward our vantage point would have its light path curved in tandem with the spacetime curve. This can create a magnifying effect.

The concept of gravitational lensing was first predicted by Albert Einstein in his theory of general relativity, and it's how scientists were able to observe GLIMPSE-17775 — essentially turning 30 hours of observing time into just about 80.

"When we saw the spectrum for the first time, it was like having all the pieces of a puzzle scattered on the floor," Kokorev said. "We picked up each piece of the puzzle, measured the lines, and started combining the different pieces into a mosaic. Maybe a few pieces looked like nothing at first, but then a couple of them came together, and we realized that there was something there."

The team identified several lines of evidence in the JWST observations that indicate "little red dot" GLIMPSE-17775 is indeed a black hole star. This includes emissions from elements that don't conform with what would be expected in a rotating gas cloud. The emission lines instead indicate the scattering of electrons, which is expected when a source of radiation is enshrouded by a vast and dense cocoon of gas. Also indicative of a dense shroud of gas were signs of fluorescence and helium-absorbing radiation.

The team also saw spectral lines from iron, which the team dubbed an "iron forest." That is something expected as a result of the high-energy output of a rapidly feeding supermassive black hole: a black hole star.If little red dots are rapidly accreting supermassive black holes shrouded by dense gas envelopes, this would explain why these mystery objects are so faint in X-rays, as these cocoons should absorb this high-energy radiation.

There is something missing from observations of GLIMPSE-17775, however.

Little red dots usually have a strong characteristic dip in the spectra of light they emit, what's known as a "Balmer Break." The team thinks this feature is weaker for this little red dot than others because GLIMPSE-17775 is surrounded by a massive host galaxy. The team's data therefore fits as a missing piece of the puzzle of little red dots, slotting in nicely with our understanding of the evolution of the universe.

"Everything fits, nothing is broken, and I think that makes the puzzle that is our universe even better," Kokorev concluded. "Looking ahead, I’m eager to dive deeper and learn about what is powering the central engines of little red dots. While we think it’s a black hole, there are some other interesting theories being proposed, which is exciting. "Maybe in a year or two, we’ll have the final answer to what powers these sources."

The team's research was published on Wednesday (June 10) in The Astrophysical Journal.

When we think about a black hole, we probably picture some vast cosmic titan, greedily consuming any matter unfortunate enough to fall within its gravitational influence. Thinking deeper, we probably imagine this ravenous cosmic beast forming from the explosive collapse of the core of a massive star. Maybe we even picture a supermassive black hole at the heart of a galaxy, formed from a multitude of mergers between smaller black holes and reaching masses millions or even billions of times that of the sun.

However, as accurate as this picture is, many scientists have long suspected that it is only the tip of the black hole iceberg, representing a single class of "astrophysical black holes" alone. These researchers theorize that black holes can also form at much more diminutive sizes that do not require the existence and death of massive stars or prior pairs of black holes. In particular, many scientists think that tiny black holes, with masses as small as that of a medium-sized asteroid, could have formed directly from density fluctuations in the hot and dense matter that filled the cosmos moments after the Big Bang. These objects have remained hypothetical as evidence of their existence has proved elusive. That hasn't stopped researchers thinking about non-astrophysical black holes and the routes to their formation, however.

One example is new research from scientists from Goethe University, Frankfurt, and the Vienna University of Technology (TU Wien), which suggests that minuscule black holes could form when the very fabric of space and time, united as a four-dimensional entity called "spacetime," undergoes critical collapse and organizes itself into a regular crystal-like arrangement. Though the idea isn't entirely new, the team has become the first to mathematically describe this transformation. And what is most staggering, they did it with nothing more than a pen and paper!

While astrophysical black holes form from some of the universe's most titanic and violent events, like core-collapse supernovas or black hole mergers, that set the very fabric of spacetime ringing with gravitational waves that can be "heard" from millions and even billions of light-years away, the team found these critical collapse black holes could be born with only a tiny nudge.

"Sometimes a tiny, seemingly insignificant cause is enough to trigger a huge and dramatic change," team member Daniel Grumiller of TU Wien told Space.com. "These microscopic black holes would form if you have a spacetime crystal and you inject an arbitrarily small amount of energy - a bit like what you get when you have undercooled water and you shake it so that it crystallizes."

Grumiller explained further that when liquid water is at its freezing point, only a small change is required to cause water molecules to spontaneously arrange themselves into a regular pattern and form an ice crystal. Even a tiny change in the structure of spacetime can allow a repeated pattern to develop, resulting in the emergence of a spacetime crystal, the team theorizes. This can kick-start the process of critical collapse.

"You can think of the critical spacetime crystal as water at freezing point; even though it is still water, it already 'knows' about ice, and small perturbations can convert water at 0 Celsius into ice, or vice versa," Grumiller said.

Enter stage left spacetime

Einstein suggested in his 1915 theory of gravity, general relativity, that particles of mass causethe very fabric of spacetime to curve. That means when particles move through spacetime, they affect the fabric of spacetime itself. That was the revolutionary thing about Einstein's rethink of gravity: to Newton, space and time were merely a stage upon which the actors of the universe, energy and matter, play their roles. To Einstein, spacetime was part of the production. It's that active role that allows for the formation of astrophysical black holes and their diminutive counterparts.

"We say that spacetime is curved by mass," Christian Ecker from the Institute for Theoretical Physics at Goethe University Frankfurt said in a statement. "Large objects such as stars curve spacetime strongly — for example, we can observe this when light rays are deflected by massive stars. But smaller masses also produce spacetime curvature, just to a lesser extent." However, because tiny black holes are hotter than their astrophysical counterparts, they rapidly "leak" thermal radiation called "Hawking radiation" to the cold of space; these spacetime crystal black holes would rapidly evaporate.

"This spacetime crystal is a very peculiar and fascinating object. It is a kind of intermediate state, an unstable point that can evolve in two different directions,” Grumiller continued. "After some time, the instability will kick in and either the spacetime crystals disperse into radiation or collapse into a small black hole. In case the crystal collapses to a black hole, it will be classically stable."

Grumiller explained that one surprise this research delivered was just how simple their mathematical descriptions of this process were while presenting solutions to the equations of general relativity.

"We provided the first paper-and-pencil solutions for spacetime crystals. Before our work, there were only numerical simulations but not exact solutions to the Einstein equations," Grumiller said. "We were astonished that the solutions were so simple that they fit into a few lines and only involved elementary functions - this was quite unexpected given the complexity of corresponding numerical simulations that take thousands of computer processing hours."

Of course, all this is great, but proving that critical collapse black holes could exist and that this route could have created primordial black holes in the dense particle-rich conditions shortly after the Big Bang doesn't actually prove primordial black holes exist.

"If we are lucky, our experimental colleagues will, at some point, discover primordial black holes. But even if this never happens, understanding critical collapse means understanding an important and conceptually rich part of general relativity, our currently best theory of gravity," Grumiller concluded. "Our next step is to find out if our various conjectures about the behavior of critical spacetime crystals are correct."

The team's research was published in the May edition of the journal Physical Review Letters.

Astronomers have discovered a distant quasar — or active nucleus of a galaxy — that's powered by a feeding supermassive black hole blasting out winds at record-breaking speeds of 30% the speed of light, around 201 million miles (323 million kilometers) per hour. This is the fastest black hole wind seen specifically in ultraviolet wavelengths.

The black hole-powered quasar, known as J2318, has an incredible mass of 1.7 billion times that of the sun and is located around 3 billion light-years away. While that is a pretty typical mass for a supermassive black hole, the speed of these winds is anything but typical, according to team member and York University researcher Patrick Hall.

"In terms of its speed, this quasar's wind could be called a category 79 hurricane," team leader and York University researcher Lucas Seaton said in a statement. "Every category of hurricane is about 20% faster than the category below it. Calling it category 79 gives an idea of just how fast it is, but of course this wind is unlike anything on Earth."

All large galaxies are thought to host a supermassive black hole at their hearts with masses of millions, or even billions, of times that of the sun, but not all of these cosmic titans power quasars or emit such incredibly powerful winds. Quasars occur when these central supermassive black holes are surrounded by vast amounts of gas and dust called accretion disks. These disks gradually feed the black holes.

Black hole winds vs. Earth winds

As you might imagine, masses of millions or billions of times that of the sun generate incredible gravitational forces, and this means accretion disks can have powerful tidal forces of their own that create friction and cause them to glow brightly across the electromagnetic spectrum. This radiation also pushes matter away from accretion disks in the form of intense black hole "winds."

"In quasars, we often see winds of gas pushed away from the black hole by the light of the quasar," Seaton said. "The wind in J2318 can be seen at ultraviolet wavelengths at velocities up to 30% the speed of light. Even faster winds can be seen at X-ray wavelengths, but J2318 is the fastest ever discovered at ultraviolet wavelengths."

The fact that black hole winds are radiation-driven, pushed by particles of light called photons bouncing off atoms (and not caused by air pressure) is what makes these cosmic gales so different from Earth's atmospheric winds.

"Quasars put out so many photons that those tiny pushes add up to extreme velocities," Seaton said. "The problem is, the photons can also remove all the electrons from the atoms, making them invisible. How to push the gas to the speeds we see while keeping the carbon and silicon ions we see intact … it's quite a puzzle!"

To tackle this puzzle, the team turned to data observations made by the SDSS-IV Time-Domain Spectroscopic Survey and the SDSS-V Black Hole Mapper as part of the wider Sloan Digital Sky Survey (SDSS).

"Just as a rainbow spreads the sun's light into different wavelengths, colours, the SDSS spreads out the light from certain stars, galaxies, and quasars into what we call their spectra," Seaton said. "From those spectra, with practice, students learn to spot unusual quasars."

These detailed spectra from J2318 revealed the high-speed winds of this quasar in ultraviolet light. The study of black hole winds like this one is important for understanding how galaxies evolve. That is because these winds are how supermassive black holes exchange energy with their galactic homes. In particular, this energy could push away gas and dust that serves as the raw material for star formation, thus quenching star birth in galaxies.

"These extreme outflows carry incredible amounts of energy that can affect the galaxies around them. They serve as a sort of missing link: the elusive feedback between the active central region of a galaxy and the rest of the galaxy," Paola Rodríguez Hidalgo, associate professor at the University of Washington at Bothell, said in the statement. "While this process has been included in simulations of galaxy formation for decades, a lot more work needs to be done to understand it from observations and make sure the simulations handle it correctly."

The team and other astronomers will continue to hunt for high-speed black hole winds in ultraviolet radiation, but aren't confident they will find any as fast as the one from J2318."It won't be easy to find a faster ultraviolet outflow than that of J2318, but we are continuing this search from the nearby universe to the most distant reaches of the universe that we can see," Flores concluded.

The team's research was published on Thursday (June 4) in The Astrophysical Journal.

After searching for 50 years, astronomers have finally discovered evidence of powerful winds blowing from Sagittarius A* (Sgr A*), the supermassive black hole at the heart of our galaxy. The discovery represents a deepening of our understanding of the physics at play both around supermassive black holes and at the heart of the Milky Way.

Scientists have long proposed that black holes produce energy as they consume matter that pushes material away from their vicinity, a process which has been dubbed "black hole winds." That even applies to Sgr A*, which exists on a diet of gas and dust so meager For a human, the equivalent would be consuming one grain of rice every million years.

The problem is, scientists have been unable to collect evidence of black hole winds blowing through the heart of the Milky Way, resulting in a mystery that has persisted in astronomy for around half a century — that is, until now.

"Unless a black hole exists in a perfect vacuum, it must blow a wind somehow. And there is no perfect vacuum in the universe," team co-leader and Northwestern University researcher Mark Gorski said in a statement. "With new observations, this is the first time we’ve had a clean enough view to see the wind's imprint. We looked at the data and said, 'There it is. There is the thing that everybody’s been looking for for 50 years.'"

Seeing black hole winds is far from a breeze

Scientists have been aware for some time that feeding black holes launch powerful outflows of material around them, including jets and winds. Winds are caused when matter falling to the black hole is accelerated to near light-speed, generating pressure that pushes infalling material away. That has been seen with ravenously feeding black holes before, but not the barely feeding Sgr A*. Its sparse consumption of material and the fact it is obscured by the plane of the Milky Way from our vantage point have made tracing this wind difficult.

Gorski's Northwestern colleague and team co-leader Lena Murchikova pointed out that the scientists were the first to detect molecular gas very close to Sgr A* feeding the supermassive black hole. That makes Sgr A* reassuringly like other supermassive black holes.

"The wind is not powerful, and its direction probably wanders with time. It shows that our black hole is not unique, and our place in the universe is not unique," Murchikova added. "To observe our own black hole, we have to look through the plane of our galaxy. That means we have to peer through gas, dust and ionized structures, and you can’t really see through all of that easily.”

To tackle these difficulties, the team turned to five years of deep observations of the heart of the Milky Way collected by the Atacama Large Millimeter/Submillimeter Array (ALMA), 66 radio antennas located in northern Chile. This delivered the sharpest image yet of the cold molecular gas with around 3 light-years of Sgr A*.One aspect of these observations that stunned the scientists was a three-light-year-long, cone-shaped cavity in this cloud of cold gas. They reasoned that this cavity must have been cleared by hotter gas in a black hole wind sweeping through the region, either pushing the cold gas in front of it or heating the cold gas.

"If you blow hot material from the black hole, it's not going to want to exist with the cold material," Gorski said. "It's either going to push the cold material out or heat it up. And, if it's too hot, you will no longer see the cold gas."

The region around Sgr A* is packed with stars — and stars also blow winds of material from them — but the team reasons that these stellar winds would not carry enough energy to carve out such a large cavity.

"It's a huge absence of material. We calculated how much energy was needed to create this cavity. It is more than can be provided by the stars in that area," Gorski explained. "Basically, there has to be input from the supermassive black hole. And, if you follow the shape of the cone, it's pointed directly at the black hole.”

To double-check their results, the scientists turned to observations of the same region made by NASA's Chandra X-ray space telescope.

"Exceptional claims require exceptional evidence," Gorski said. "We wanted to make sure that we weren't just looking at some sort of imaging artifact. Then, the X-ray image from Chandra just slotted in perfectly. The molecular features lined up."

This backed up the results from ALMA by revealing X-ray emissions coming from the location of the cavity in the cold gas.

"When you find something that no one has seen before, the first thought that runs through your mind is not 'Oh my god, we made a discovery,'" Murchikova said. "It's 'Oh my god, what's wrong with my analysis?' But when we overlaid our image with the X-ray image, it started to make sense."

While the team's results confirm that Sgr A* is extremely quiet compared to the supermassive black holes that sit in bright, turbulent regions of other galaxies called active galactic nuclei (AGN), this black hole wind is no slouch. In fact, the scientists think that it has been raging for around 20,000 years.

"The majority of other galaxies spend most of their lives in a state where they are not particularly active," Murchikova said. "But we can only see them when they are in a fireworks stage. It is very attractive to study black holes when they are in the fireworks stage, but that’s not actually their dominant state. "Sgr A* finally gives us a window into the life of a black hole in this quiet state."

The team's research was published on Thursday (June 4) in The Astrophysical Journal Letters.

New research suggests that black holes born during the Big Bang could live much longer than previously estimated. In fact, these tiny primordial black holes may live long enough to become energy-spewing white holes with the mass of a human eyebrow hair.

Primordial black holes are proposed to have formed through fluctuations in the incredibly hot and dense matter that filled the universe moments after the Big Bang. This is in contrast to stellar-mass or "astrophysical" black holes that are familiar to us the collapse of massive stars like the. Primordial black holes remain undetected and therefore hypothetical.

Many scientists believe that the failure to detect astrophysical black holes is because they have evaporated and therefore no longer exist in the 13.8 billion year-old cosmos. This is possible because black holes are proposed to "leak" a type of thermal radiation called "Hawking radiation" proposed by Stephen Hawking in the 1970s. The smaller the mass of a black hole, the hotter it is, and thus the faster it leaks Hawking radiation and the more rapidly it evaporates, a process speculated to end with an explosive finale.

Stellar-mass black holes, with up to hundreds of times the mass of the sun, are massive and cool enough to leak slowly enough to outlive the universe itself many times over; primordial black holes with masses way smaller than this, on the other hand, aren't so lucky — or so we thought. Eberly College of Science researcher Daniel Paraizo and colleagues suggest there is a way that primordial black holes of just the right mass could survive this process to undergo a startling transformation.

"We found that the lifetime of black holes is much longer than previously thought," Paraizo told Space.com. "The phenomena that we identify are relevant for black holes possibly formed in the early universe. These objects have not been observed yet, but their search is a topic of intense interest as dark matter candidates. Black holes start to die by emitting thermal Hawking radiation. The puzzle is what happens once they reach the Planck mass, which is around 20 micrograms."

A black hole the size of a flea egg

The Planck mass of around 0.000000022 kilograms is a fundamental unit of mass in physics considered fascinating because it is the point at which the rules that govern subatomic particles and quantum physics as well as those that govern gravity and general relativity as a whole become equally important. Physicists consider this the upper limit for the mass of any single elementary particle, with any particle above this collapsing to birth a microscopic black hole.

In everyday terms, the Planck mass is about equivalent to a human eyebrow hair, or a flea egg, which is about one-fifty-thousandth as heavy as a jelly bean.

Paraizo explained that once a primordial black hole has evaporated to the Planck mass, becoming a so-called Planckian black hole, there are several proposed fates it could encounter. This includes the disappearance of the outer boundary that defines what a black hole is, the light or electromagnetic radiation trapping region known as the event horizon. "The mechanism that we study for the death of this Planck-sized black hole is the gradual disappearance of the horizon that traps radiation," Paraizo said.

The team performed mathematical calculations that revealed a primordial black hole formed with the initial mass of a medium-size asteroid, around 1 billion tons, decays in about a billion years and emits thermal Hawking radiation until it reaches the Planck mass. However, a primordial black hole born with a mass of just 1 ton would immediately explode, instantly reaching the Planck mass. It is what happens next that sets the team's findings apart from previous research. "It is then that our results predict something new: previous arguments indicated that the remaining 20 micrograms are radiated in at least 1 second; our estimate shows instead that these 20 microgram remnants are practically stable," Paraizo explains. "Once the black hole reaches the 20-microgram threshold, we find that it starts emitting purifying radiation [named because it is said to 'purify' the quantum state of the universe] due to behavior that is characteristic of a white hole.

"Therefore, even though we do not yet know the physics near a white hole, we identify an object that has exactly the same properties from far away."

White holes are another hypothetical entity in physics, suggested to be effectively a "time-reversed black hole" that, rather than trap matter and radiation within them as black holes do, endlessly push matter and radiation away.

Any further predictions about the fate of these primordial black holes taking on a white hole appearance would require a theory that unites general relativity and quantum mechanics, known as "quantum gravity," that has steadfastly evaded physicists since the early 20th century.

"Simple physical assumptions about the physics far away from a black hole can tell us a lot about their lifetime and about their transition to a stable phase that looks like a 20 microgram white hole," Paraizo said. "The fact that we can infer these properties, using only minimal ingredients from quantum gravity, is remarkable."

A pre-peer-reviewed version of the team's research is available on the research repository site arXiv.

Astronomers have struck "black gold" — a treasure trove of black hole mergers. And the discovery was made by analyzing ripples in the very fabric of space and time, or spacetime, called gravitational waves.

This massive haul of mergers contained within the Gravitational Wave Transient Catalogue-5.0 (GWTC-5), released on Tuesday (May 26), could change our understanding of how black holes meet and collide. The latest catalog contains 161 new gravitational wave signals launched by merging black holes "heard" by iconic gravitational wave detectors LIGO (Laser Interferometer Gravitational-Wave Observatory), Virgo, and KAGRA (Kamioka Gravitational Wave Detector) between April 2024 and the end of January 2025.

It brings the total number of black hole mergers detected via gravitational waves up to 390.

Highlights of GWTC-5 include the detection of "second generation mergers," or collisions between two black holes that had formed in previous mergers, and the most precisely localized merger ever. While the former could help us better understand merger chains that allow black holes to grow to masses millions or even billions of times that of the sun, the latter could help develop a method of using such events and their gravitational wave signals to measure the rate at which the universe is expanding.

"This bumper update has once again broadened and deepened our knowledge of the universe, and given us many more glimpses of its most elusive objects: colliding black holes," Daniel Williams, a research fellow at the Institute for Gravitational Research, said in a statement. "We're now detecting so many of these signals that we're not just learning about individual collisions; it's the astronomical equivalent of uncovering an ancient civilization.

"Today's new results are like finding a previously undiscovered hoard, revealing not just individual lives, but the structure of an entire lost world."

What are gravitational waves?

Gravitational waves were first proposed in 1915 as part of Albert Einstein's theory of gravity, known as general relativity. General relativity suggests that objects with mass cause spacetime (the four-dimensional unification of space and time) to warp. Gravity arises from this warping, meaning the larger the mass, the greater the curvature of spacetime and the stronger the gravitational influence.

General relativity goes beyond this, also suggesting that when objects accelerate in spacetime, they create ripples that radiate outward at the speed of light: gravitational waves. Though Einstein initially predicted this rippling of spacetime, he was wrong about one aspect of gravitational waves: he thought humanity would never detect them.

LIGO made the first detection of gravitational waves in 2015; the signal came from the collision and merger of two massive black holes located around 1.3 billion light-years away. Since then, along with its fellow detectors Virgo and KAGRA, LIGO has detected gravitational waves from many mergers between pairs of black holes, pairs of ultra-dense neutron stars — and even mixed mergers between a black hole and a neutron star.

The sensitivity of the gravitational wave detectors has only increased in recent years, with detections currently occurring as frequently as three to four times each week during observational run phases between down periods that allow further advancement of sensitivity.

"Just 10 years ago we made the first detection of gravitational waves from one of these events, and it's a real testament to the work of hundreds of scientists around the world that we're now detecting and analyzing hundreds of them," Williams said.

Gravitational wave detections are making some noise

Two impressive demonstrations of the importance of the data from GWTC-5 are the signals GW241011 and GW241110 detected on Oct. 11, 2024, and Nov. 11, 2024, respectively. They are the result of two mergers 700 million light-years away and 2.4 billion light-years away, and the rapid spin of the involved black holes and the orientation of that rotation implied that these four black holes were second-generation objects, meaning they were created by prior mergers.

"These two observations showed characteristic signs that the larger black hole in each pair was formed not directly from a massive star, but from a previous merger of two black holes," Storm Colloms of the Institute for Gravitational Research said in the statement. "The signatures of black holes formed from previous mergers persist in the population as a whole, indicating that GW241011 and GW241110 are not one-of-a-kind, but trace an underlying trend. Now, we have growing evidence that there are ways that the universe creates merging black holes in addition to those that come from massive binary stars."

This indicates that these two mergers occurred in densely packed stellar environments, something that will be difficult to investigate because it isn't easy to localize a gravitational wave signal back to its point of origin. That isn't always the case, as was demonstrated by the signal GW240615, detected on June 15, 2024.

The result of a 26-solar-mass black hole merging with a 30-solar-mass black hole over 3 billion light-years away, gravitational wave astronomers were able to pinpoint GW240615 to a region of the sky measuring just 6 square degrees. That makes GW240615 the most precisely localized gravitational wave signal to date.

"The updated GWTC-5.0 catalogue gives us a much larger collection of gravitational-wave signals to help answer one of the biggest questions in cosmology: how fast is the universe expanding?" Alex Papadopoulos of the Institute for Gravitational Research said in the statement. "The rate of this expansion is described by a value called the Hubble constant. Gravitational waves allow us to measure this by estimating how far away merging objects are, either directly from the signal itself or by identifying the galaxy where the merger took place.

"Each event contributes a small amount of information, so together these additional signals significantly improve our results. Together, these improvements help us measure the Hubble constant more precisely than ever before using gravitational waves, bringing us closer to understanding one of modern physics’ most important open questions."

Also standing out in this latest catalog is the gravitational wave signal GW250114 detected on January 14, 2025. This is believed to be the result of a 34 solar mass black hole colliding and merging with a 32-solar-mass black hole around 1 billion light-years away. This signal was so clear that it allowed researchers to perform the most accurate test of general relativity ever, in addition to confirming a concept introduced by Stephen Hawking called the black hole area theorem.

"With the loudness of GW250114 we are able to compare the warped space-time before and after the black holes merged, and found that the total area of the event horizons [the light-trapping outer boundary of a black hole] increased in accordance with Hawking's laws of black hole mechanics," John Veitch of the University of Glasgow said in the statement. "After the merger the final black hole rings like a bell, giving off gravitational waves instead of sound. Analyzing these waves confirmed that although energy is given off in gravitational waves during the merger, the total entropy of the black holes increases in accordance with the second law of thermodynamics.

"This shows that even for black holes the laws of thermodynamics still apply, but unlike normal objects, the more energy they hold, the colder they become."

It is very likely that LIGO, Virgo and KAGRA will continue to make gravitational wave discoveries that redefine our understanding of the universe and its most violent events. The detectors are set to begin a six-month intermediate observing run (IR1) later this year. This will bridge the gap between the end of Observing Run 4, which concluded on Nov. 18, 2025, and the beginning of Observing Run 5, which will operate between 2028 and 2031.

The future is bright for gravitational waves — or should that be "loud?"

Observations of ancient galaxies called "Little Red Dots" by the James Webb Space Telescope (JWST) could finally answer the question: which comes first, the black hole or its galaxy? It turns out that the answer isn't what scientists expected and could thus represent a complete paradigm shift in our understanding of how black holes grow.

Little Red Dots were first spotted in 2022 by the JWST, immediately presenting themselves to astronomers as something completely new, perhaps a type of galaxy never seen before. The mystery of these objects deepened when scientists discovered that they are remarkably common in the infant universe but seem to disappear around 1.5 billion years after the Big Bang. But Little Red Dots are far from the only cosmic mystery that the JWST has dropped into the lap of scientists.

The $10 billion space telescope has also discovered a wealth of supermassive black holes with masses millions to billions of times that of the sun prior to the universe being 1 billion years old. That is problematic because the feeding and merging processes that allow black holes to grow to supermassive status had always been thought to take longer than 1 billion years.

This new study of Little Red Dots by the JWST indicates that maybe supermassive black holes were born directly without needing a massive star to live for millions of years before collapsing to birth a stellar-mass black hole. It also means that these early supermassive black holes would not need to gorge on copious amounts of gas and dust from their host galaxies to grow. That means these black holes could form before the galaxies that will eventually host them come together.

"This is a remarkable finding," team member Roberto Maiolino of the University of Cambridge in the United Kingdom, said in a statement. "It's a paradigm shift, a total revisiting of the classical scenarios of how black holes form and grow." The team's research was published on Wednesday (May 27) in the journals Nature and the Monthly Notices of the Royal Astronomical Society

Little Red Dots put black holes on the spot with help from Einstein

To reach their conclusion, scientists focused on the Little Red Dot designated Abell2744-QSO1 (QSO1), which existed 700 million years after the Big Bang. This means that the light from this ancient galaxy, which is just 1,300 light-years wide, has been travelling to Earth for just over 13 billion years.

QSO1 is easier to study than other Little Red Dots because of a phenomenon called gravitational lensing.

First suggested by Einstein in 1915, gravitational lensing occurs when an object of great mass sits between a more distant background object and Earth. As light passes this middle or "lensing" object, its path is curved by the warp in spacetime the lensing body causes; the closer to the object the light passes, the more curved its path is. This means light from the background objects can arrive at our telescopes at different times, thus magnifying the background object.

In the case of QSO1, this Little Red Dot is being gravitationally lensed by the galaxy cluster Abell 2744, also known as Pandora's Cluster.

Researchers had initially thought that QSO1 is actually just a supermassive black hole with a mass 40 million times greater than the sun, surrounded by a cloud of hydrogen and helium gas. However, scientists couldn't be entirely sure about the mass of this black hole.

"Before now, all of the mass measurements of black holes in the early universe have been indirect, based on assumptions from what we know about them in the local universe," team member Francesco D'Eugenio, also of the University of Cambridge, said. "We didn't know if those assumptions really apply to the distant universe."

This team reasoned that if the black hole heart of QSO1 is as massive as initially thought, then its mass should be observable in the motion of the gas swirling around it. They therefore used the JWST's NIRSpec (Near Infrared Spectrograph) instrument to map the motion of this gas, finding it orbits a central point similar to how the planets of the solar system orbit the sun, a phenomenon called Keplerian motion.

"This is important because it tells us that most of the mass of QSO1 is concentrated in the black hole at the center," team co-leader Ignas Juodžbalis of Cambridge University said. "If the mass were more distributed, as it would be if there were a lot of stars, the gas would not have this perfect Keplerian rotation."

This allowed the team to directly measure the mass of QSO1's central black hole for the first time.

"This is a phenomenal result," Maiolino added. "It is the first direct measurement of a black hole mass within the first billion years after the Big Bang, and it is consistent with the previous measurements."

This revealed that at 50 million solar masses, the supermassive black hole accounts for an incredible 66% of the total mass of this Little Red Dot. That is a ratio that is thousands of times greater than the ratio of supermassive black hole mass to galaxy mass found in the local universe.

That ratio indicates that this black hole can't have been born from a collapsing star and gradual feeding from the surrounding galaxy, indicating it was born "big" and now has what will eventually grow to be a galaxy taking shape around it.

There are still mysteries to solve surrounding the black hole of QSO1, particularly questions of how it formed. The team thinks that the black hole could have grown from a "heavy seed" born from a collapsing cloud of gas and dust. Or alternatively, it could have been birthed directly during the initial moments of the Big Bang through an as-yet unknown process

What the team is relatively sure of is that QSO1 cannot be rare among Little Red Dots in the early universe. They are now assessing other Little Red Dots to determine if these also harbor supermassive black holes with galaxies in the process of forming around them.

Scientists have discovered an ultra-powerful "ghost particle" or neutrino, which struck Earth and was detected in the Mediterranean Sea in 2023, may have been blasted at Earth by blazars powered by a feasting black hole engine.

Blazars are a type of quasar, the regions at the hearts of galaxies that host feeding supermassive black holes and discharge powerful jets of radiation. Blazars are different from "ordinary" quasars because their orientation means that the energy, particles, and jets of plasma they blast out are pointed directly at Earth.

The neutrino was 30 times more energetic than carried with it 30 times the energy of the previous most energetic neutrino ever detected. It arrived at Earth on Feb. 13, 2023, traveling at nearly the speed of light, and was spotted via the detection of a single muon (a subatomic particle) by the Kilometer Cubic Neutrino Telescope (KM3NeT), located 11,300 feet (3,450 meters) beneath the waves of the Mediterranean Sea. Blazars were initially suggested as the source of the particle, but this team of scientists took it upon themselves to confirm a specific class of these supermassive black hole-powered events as a possible origin.

"There are several possible explanations for the origin of this particle," team member Meriem Bendahman, from the KM3NeT collaboration, said in a statement. "For example, it has been proposed that such neutrinos are generated when ultra-high-energy cosmic rays interact with the cosmic microwave background radiation (CMB), the residual light from the early universe. But there is also the possibility that the neutrino originates from a diffuse flux produced by a population of extreme accelerators, such as blazars."

A high-energy 'ghost'

Neutrinos get their nickname of "ghost particles" from the fact that they have no electric charge and are virtually massless, meaning they pass through matter with little to no interaction. In fact, as you just read that sentence, around 100 trillion neutrinos passed through your body at nearly the speed of light. That makes detecting neutrinos incredibly difficult, even when like this one, they carry an energy of 220 million billion electron volts.

For context, that is 30,000 times the energy that Earth's largest particle accelerator, the Large Hadron Collider (LHC), is capable of achieving. In fact, to accelerate a particle to such energies, the LHC would have to be expanded from its current length of 17 miles (27 kilometers) to around 25,000 miles (40,000 kilometers), the entire circumference of the Earth.

Little wonder scientists are eager to understand where this particle came from and how it was boosted to such high energies.

The team began sorting through possible origins for this high-energy neutrino particle by acting like cosmic forensic detectives, classifying the detection of the particle as a crime scene and hunting for potential clues that point toward a culprit.

One of the first clues discovered by the researchers was the absence of an electromagnetic radiation signal in radio, optical, X-ray, or gamma rays from the same region of space that the neutrino appeared to have originated from. That is something that they would expect to see if the particle had been launched by a single explosive event like a stellar flare or a supernova.

"This does not completely rule out the possibility of a point-like source, but it leads us to consider that our neutrino may come from a diffuse background — that is, from a flux of neutrinos including contributions from many sources," Bendahman said.

Sources like a population of black hole-powered blazars.

Bendahman simulated a population of blazars, taking into account observations of their characteristics such as magnetic field strength and the range of radiation they emit. Their simulations allowed them to vary two important parameters: the energy carried by protons compared to electrons (called "baryonic loading") and how that energy is distributed across the protons; and how likely particles are to reach ultra-high energies. This second parameter determines how many neutrinos can be created, the neutrino flux (the intensity of a stream), and how many gamma-rays are created.

The model developed by the researchers also had to account for the lack of detection of neutrinos of similar high energies by KM3NeT, still under construction off the coast of Sicily, and by other facilities such as the IceCube Neutrino Observatory located in Antarctica. That meant any event that created such a high-energy neutrino must be relatively rare.

Additionally, as neutrino creation is accompanied by gamma-ray emission, the model had to ensure that in creating high-energy neutrinos, blazars didn't generate enough gamma-ray radiation to exceed the extragalactic gamma-ray background measured by the Fermi space telescope.

"We modelled a realistic population of blazars with physically motivated parameters, and we found that this population of blazars could explain the origin of this ultra-high-energy event, while also being consistent with the constraints that we have regarding the gamma-ray and neutrino observations," Bendahman said.

While the team's findings do indeed show that a population of blazars could be responsible for this high-energy neutrino, the case is far from closed.

"We need more observational data," Bendahman said. "We have never observed such a high-energy neutrino before, and if it turns out to come from cosmic accelerators like blazars, it would give us new insight into how these objects can emit particles at energies beyond what we previously expected."

The team's research was published in the Journal of Cosmology and Astroparticle Physics (JCAP).

The most mysterious and yet ubiquitous stuff in the cosmos, dark matter is effectively invisible. This is simply because it doesn't interact with light. But what if instead of trying to see dark matter, scientists attempted to hear it instead?

New research suggests dark matter could leave a tiny but discernible imprint in the cacophony of ripples in spacetime called "gravitational waves" that ring through the cosmos when two black holes slam together and merge. However, this is only if spinning black holes can "churn" dark matter like cosmic butter. (We'll get to that shortly.)

The team behind this new research suggests that if two black holes merge in a region of space populated by dense dark matter clouds, then the gravitational waves emerging from the event could carry the imprint of dark matter across the universe. And it's possible, they say, that our detectors could find that imprint. This would be akin to someone coughing at a Metallica concert, and that cough being only discernible over the fury of "Seek and Destroy" or "Master of Puppets" with the most sensitive instruments.

Fortunately, when it comes to detecting gravitational waves from colliding black holes, humanity's instruments, such as LIGO (Laser Interferometer Gravitational-Wave Observatory), are getting more and more sensitive all the time. And in preparation for a time when such imprints could become even more easily logged in gravitational wave data, this team developed a method that predicts just what shape a gravitational wave should take when moving through dark matter, rather than empty space.

"Using black holes to look for dark matter would be fantastic," team member Rodrigo Vicente, a researcher at GRAPPA (Gravitation Astroparticle Physics Amsterdam), said in a statement. "We would be able to probe dark matter at scales much smaller than ever before."

I can't believe it's not butter

Dark matter represents such a puzzle because, despite being invisible to us, it still "outweighs" ordinary matter by a ratio of about five to one.

Its lack of interaction with light means it can't be composed of protons, neutrons and electrons — the particles that compose atoms. That's because atoms compose all the "ordinary matter" we see around us, from stars and planets to the device you're reading this article on and our own bodies. In other words, atoms do interact with light (more technically, electromagnetic radiation). In fact, the only way astronomers know dark matter exists is via its interaction with gravity and the way this interaction curves spacetime, indirectly influencing ordinary matter and light.

With this knowledge, scientists have been hunting for particles outside the Standard Model of particle physics that could account for dark matter. These particles have a wide range of potential masses and properties, with one hypothetical particle being the "light scalar" proposed to have a mass much smaller than that of an electron. One characteristic of the light scalar would be the fact that dark matter composed of these particles would act like coordinated waves around black holes.

Around a spinning black hole, rotational energy would be transferred to light scalar dark matter, amplifying its density, almost like a paddle churning cream into butter. If this dark matter "butter" gets dense enough, it could affect gravitational waves from merging black holes, leaving a telltale imprint.

After determining what this signature would look like, Vicente and colleagues searched through data gathered by LIGO and its fellow gravitational wave detectors, KAGRA (Kamioka Gravitational Wave Detector) and Virgo, focusing on 28 of the clearest signals from merging black holes. Of these, 27 appeared to have come from mergers that occurred in the relative vacuum of space. One signal, however, GW190728, first heard on July 19, 2019, and the result of merging binary black holes with a combined mass of 20 times that of the sun and located an estimated 8 billion light-years away, seemed to carry the telltale trace of this merger occurring in a region of dense, "buttery" dark matter.

The team behind this research is quick to point out that this can't be considered a positive detection of dark matter, but does say it gives us a hint at what to look for and thus where to direct follow-up investigations — something that could be increasingly useful as dark matter detectors on Earth continue into their fifth operating run with boosted sensitivity.

"We know that dark matter is around us. It just has to be dense enough for us to see its effects," said team leader Josu Aurrekoetxea, of the Massachusetts Institute of Technology (MIT) Department of Physics. "Black holes provide a mechanism to enhance this density, which we can now search for by analyzing the gravitational waves emitted when they merge."

The team's results were published on Tuesday (May 12) in the journal Physical Review Letters.

Out in the universe, there exist mysterious and powerful bright blue cosmic explosions called Luminous Fast Blue Optical Transients (LFBOT) — and new research may finally have some answers as to where these strange blasts come from.

The first of these explosions was spotted in 2018, and only 14 have been detected since, leading to a solid mystery for astronomers. Now, however, the team behind the new research believes the events are caused when a compact stellar remnant, like a black hole or a neutron star, slams into the universe's hottest class of star, massive stellar bodies called Wolf-Rayet stars.

Scientists have been trying to figure out the origins of LFBOTs for quite some time and have even proposed a wealth of models to account for the existence of these events. The interest likely comes from LFBOTs remarkably evolving faster than other cosmic explosions, or "transients," peaking and fading in a matter of days. LFBOTs also stand out because of their unique color: They remain blue throughout much of their evolution, indicating they stay incredibly hot all throughout.

Those other proposed potential origins for LFBOTs range from the death of massive stars in so-called core-collapse supernovas to extreme tidal disruption events (TDEs), involving very massive black holes ripping up and devouring stars. To get to the bottom of things, though, the team behind the new research examined the host galaxies and environments of LFBOTs to try to pin down what the progenitors of these explosive events could really be. This analysis revealed that LFBOTs emerge from very different environments than those generated by some of those suggested supernova scenarios, and do not occur in the environments generally expected for tidal disruption events.

"Because LFBOTs are so rare and their light-curve properties are so different than many other transients, it is hard to pin down what their progenitors are! They obviously represent some unique astrophysical phenomena, but what that could be has remained an open question," research team leader Anya Nugent of Harvard University's Center for Astrophysics (CfA) told Space.com. The model Nugent and colleagues have homed in on for LFBOTs is the collision of a compact stellar remnant with the leftover helium core from a massive star that has had its outer hydrogen envelope ripped off — a Wolf-Rayet star.

"We think that describes both the transient and host properties well," she explained.

What leaves Wolf-Rayet stars feeling blue?

As opposed to the other models meant to explain LFBOTs like TDEs and core-collapse supernovas, the team's proposed compact object and Wolf-Rayet merger model does appear to easily justify all of the LFBOT transient and environmental properties, Nugent pointed out.

Nugent explained that the mergers may prefer more star-forming and less massive galaxies as host environments, unlike core collapse supernovas which tend to occur in more stellar-dense massive galaxies. These, she said, are perfect for creating binary systems that begin as two massive stars with one stripping the other of stellar matter, turning the "donor" into a Wolf-Rayet star. That donor star eventually pushes the "cannibal" star toward the core-collapse supernova that will turn it into a black hole or neutron star. Eventually, the Wolf-Rayet star and its stellar remnant companion will merge to launch an LFBOT. That's important because though binary stars are common, not just any binary system could launch an LFBOT.

"Many massive stars are in binary systems, but these mergers occur in just the right conditions that they don’t merge with each other too early on in their evolution, but the stars are still close enough together that they can merge," Nugent said.

In the team's binary merger model, the compact object is close enough to its stellar companion to rip off its outer hydrogen layer without completely destroying the star. After hundreds to thousands of years, the feeding black hole or neutron star falls into the stellar core and destroys it, creating a luminous emission.

"This merger model will be rare, similar to the rate of LFBOTs, but not so rare that we would never expect it to happen," she added. "Essentially, these environments are perfect for creating the binary systems that will merge in this way."

The team also theorizes why LFBOTs don't seem to originate in densely packed star fields where black hole or neutron star collisions with Wolf-Rayet stars would more commonly occur.

Nugent and the team justify this by assuming the collapse of the first star in a binary system that forms the compact object, be it a black hole or a neutron star, may give the entire system a "kick" that serves to push it away from densely packed star-forming regions to more sparsely populated regions of galaxies.

"Thus, we also have justification for why LFBOTs appear to be more offset from their hosts, exploding in regions where there are very few stars, away from their birthsite, than core-collapse supernovas," Nugent said.

The team favors their Wolf-Rayet meets stellar remnant collision LFBOT origin model because they reason that the TDE and supernova models have struggled to explain all of the observed properties of these blasts. For example, LFBOTs occur in very dense "circumstellar environments." These are regions in which stars are looped by loose material, which is likely the result of the progenitor star blasting off material in the past.

"This cannot be explained easily with the TDE model or even some of the supernova models," Nugent said. "Moreover, LFBOTs have different properties and occur in different environments than TDEs and supernovas, so the big question is, if they are all coming from the same things, what is causing this distinction?"

Nugent reasons the most plausible explanation is that LFBOTs come from an entirely different channel and for the team, a neutron star or black hole slamming into a Wolf-Rayet star seems to a good fit for all the observed properties of LFBOTs.

Nugent acknowledges, however, that this origin model can only be robustly investigated once astronomers have grown the population of known LFBOTs. That discovery operation is something that Nugent expects the Vera C. Rubin Observatory and its newly begun decade-long Legacy Survey of Space and Time (LSST) to play a major role in.

"Rubin will be amazing for discovering fainter LFBOTs out to even further cosmological distances, which will not only give us a larger population but will show us how LFBOTs and their progenitors have evolved over cosmic time," she concluded.

A pre-peer-reviewed version of the team's results is available on the research repository site arXiv.

Scientists have discovered that the universe's most massive black holes may form in the densest of stellar environments, or so-called globular clusters. It is in these clusters where violent collisions are common, suggesting a chaotic new origin for these cosmic titans of our cosmos.

Scientists pinpointed this potential birthplace of massive black holes by studying ripples in space and time — unified as a single entity called spacetime — otherwise known as gravitational waves. The waves were heard" on Earth by our highly sensitive gravitational wave detectors, the Laser Interferometer Gravitational-Wave Observatory (LIGO), KAGRA and Virgo. Gravitational waves were first predicted by Albert Einstein back in 1915 as part of his theory of gravity, known as general relativity. They are launched when powerful events such as the collision and merger of black holes set the very fabric of spacetime ringing.

The team behind this research analyzed 153 black hole merger detections contained in version 4.0 of LIGO–Virgo–KAGRA's Gravitational-Wave Transient Catalog (GWTC4) with the aim of investigating if the heaviest black holes are formed by the repeated merger of successively larger black holes in dense stellar environments rather than directly from massive star collapses.

"Gravitational-wave astronomy is now doing more than counting black hole mergers," team leader Fabio Antonini from the U.K.'s Cardiff University said in a statement. "It is starting to reveal how black holes grow, where they grow, and what that tells us about the lives and deaths of massive stars. This is exciting because we can use the information to test our understanding of how stars and clusters evolve in the universe."

Mind the gap!

The team's gravitational wave investigation into the origins of the most massive black holes revealed two distinct populations of black holes. Antonini and colleagues found a population of lower mass black holes that seem to have been born when massive stars died in supernova explosions and their cores underwent gravitational collapse. They also observed a population of black holes spinning in such a way that it indicates they formed via a chain of hierarchical mergers between smaller black holes in dense star clusters.

That is a revelation that shocked even the team behind this study.

"What surprised us most was how clearly the high-mass black holes stand out as a separate population," team member Isobel Romero-Shaw of Cardiff University said. "Unlike the lower-mass systems we analyzed, which were generally slowly-spinning, the higher-mass systems are consistent with having more rapid spins, oriented in seemingly random directions. This is the exact signature you would expect if black holes were repeatedly merging in dense star clusters. That makes the cluster origin much more compelling than it was with earlier catalogues."

The team's research suggests evidence of a long theorized "mass gap" relating to the afterlife of stars. It suggests that the most massive stars don't collapse to form black holes when they die, and rather undergo a supernova blast that obliterates them completely.

That, in turn, suggests there is a forbidden mass range for stellar-mass black holes born from collapsing stars, resulting from the fact that very massive stars are disrupted before a black hole can be created. The team believes this forbidden mass range begins with a mass of 45 times that of the sun. Black holes with masses greater than this, the researchers propose, are formed by mergers.

"In our study, we find evidence for the long-predicted pair-instability mass gap — a range of masses where stars are not expected to leave behind black holes at all. Gravitational-wave detectors have successfully found black holes that appear to sit in or near that gap, which we identify at around 45 solar masses," Antonini explained. "So, the key question now is, are these black holes telling us that our models of stellar evolution are wrong, or are they being made in another way?"

The team's findings could also reveal more about the death throes of the largest stars and how stellar bodies behave when jammed into regions millions of times denser than the cosmic backyard of the sun.

"The biggest black holes in the current sample seem to be telling us about cluster dynamics, not just stellar evolution," Antonini said. "Above about 45 solar masses, the spin distribution changes in a way that is hard to explain with normal stellar binaries alone but is naturally explained if these black holes have already been through earlier mergers in dense clusters."

These results were published on Thursday (May 7) in the journal Nature Astronomy.

The discovery of an X-ray signal coinciding with the location of one of the mysterious 'little red dots' found by the James Webb Space Telescope (JWST) has strengthened the theory that the dots are 'black hole stars' — huge, dense clumps of gas energized by the presence of a growing supermassive black hole within them.

The little red dots may be the biggest cosmological discovery made so far by the JWST, and possibly the most important since the discovery of dark energy in 1998. If they are what astronomers think they are, then they would act as a crucial missing link in the formation of not only supermassive black holes but also the galaxies that grow around them.

The newly discovered "X-ray dot" was recognized when the JWST's observations of an area of sky containing little red dots was compared to archival observations of the same area by NASA's Chandra X-ray Observatory.

"The X-ray dot has been sitting in our Chandra survey data for over ten years, but we had no idea how remarkable it was before Webb came along to observe the field," said Princeton University astronomer Andy Goulding in a statement.

Chandra has identified millions of X-ray sources across the sky, but the importance of this one, catalogued as 3DHST-AEGIS-12014 (AEGIS refers to the All-wavelength Extended Groth Strip International Survey), only became apparent when it was noticed that it was in exactly the same location as a little red dot seen by the JWST. The X-ray source carries an energy not dissimilar to the X-ray energy of quasars, which are galaxies that host an extremely active black hole, often as the result of a galaxy merger stirring up gas and prompting that material to fall towards the black hole.

Little red dots are compact, being at most just a few hundred light-years across. They are also very red, meaning they are rather cool — a recent study led by Harvard's Anna de Graaf identified water vapor in them, the existence of which tells us how cool the little red dots must be, in the range of 3,092 to 6,692 degrees Fahrenheit (1,700 to 3,700 degrees Celsius). This sounds hot to us, but it is cooler than our sun and indeed most stars except for the least massive red dwarfs.

Furthermore, little red dots are very distant objects, measured to have existed 12 billion years ago, or even older still. Photometric measurements of 3DHST-AEGIS-12014 by the Hubble Space Telescope tell us that we see this puzzling object as it existed 11.8 billion years ago.

The discovery of little red dots potentially also fulfills one of the JWST's primary science goals, which is to try and trace the origins of supermassive black holes and the galaxies that assemble around them.

How supermassive black holes are born has been a mystery that has confounded astronomers. Do they form from the bottom up, as smaller stellar-mass black holes produced in supernova explosions combine with each other? Or, do they form from the top down, via the collapse of a vast gas cloud containing hundreds of thousands or even millions of times the mass of our sun?

Little red dots are thought to be huge gas clouds hiding a burgeoning supermassive black hole within them that is feeding off the cloud, eating it from the inside-out. The gas cloud glows from the heat and energy radiated from the material swirling around the black hole, and via magnetically collimated jets of charged particles that can escape the black hole's maw.

Although little red dots are not yet definitive proof that supermassive black holes form through the top-down process, they do strongly indicate that. Chandra's new discovery strengthens that hypothesis even further.

"Astronomers have been trying to figure out what little red dots are for several years," said Raphael Hviding of Germany's Max Planck Institute for Astronomy, who is the lead author of the scientific paper describing the discovery. "This single X-ray object may be — to use a phrase — what lets us connect all the dots."

If Hviding's team is correct, then this is the first little red dot to be found to shine in X-rays. Ordinary growing supermassive black holes, such as those at the heart of quasars, do shine in X-rays from matter being heated up to millions of degrees as it falls towards the black hole. However, in a little red dot the surrounding gas would absorb the X-rays before they can escape into space, so ordinarily we would not see a little red dot shining in X-rays. This marks 3DHST-AEGIS-12014 as something different.

"Finding a little red dot that looks different from the others gives us important new insight into what could power them," said de Graaf.

So why can we suddenly see X-rays coming from 3DHST-AEGIS-12014? The hypothesis is that it is a transitional object between the birth of a supermassive black hole in a little red dot, and the "naked" supermassive black holes that we see growing even larger in the center of active galaxies. Inside a little red dot, the black hole is growing by consuming the cloud from the inside out, which eventually leads to holes in the cloud that act as windows into the heart of the little red dot and the supermassive black hole that astronomers think lurks there. The X-rays are escaping through these windows.

Furthermore, although the X-ray signal is weak at such great distances, the Chandra observations suggest that 3DHST-AEGIS-12014's X-ray brightness could possibly be changing. This would happen as the huge cloud of gas rotates and different windows, some large and some smaller in size, spin into view.

The true identity of Chandra's X-ray counterpart to one of the JWST's little red dots is not yet nailed on; one outside possibility is that it could be a supermassive black hole surrounded by an exotic form of hot dust. However, such dust has never been seen before, making this scenario unlikely.

"If we confirm the X-ray dot as a little red dot in transition, not only would it be the first of its kind, but we may be seeing into the heart of a little red dot for the first time," said Hanpu Liu of Princeton University. "We would also have the strongest piece of evidence yet that the growth of supermassive black holes is at the center of some, if not all, of the little red dot population."

If this hypothesis is confirmed, then little red dots would become a crucial piece in the jigsaw of how galaxies and their supermassive black holes form, allowing astronomers to figure out the early history of galaxies such as our own Milky Way — a dream of astronomers ever since Edwin Hubble recognized that other galaxies existed beyond our own.

The research was published in March in The Astrophysical Journal Letters.

New research suggests that supermassive black holes that existed before the cosmos was 1 billion years old may have formed with a helping hand from dark matter, the universe's most mysterious stuff.

Ever since the James Webb Space Telescope (JWST) first began reporting data back to Earth in the summer of 2022, it has been delivering a curious problem into the laps of scientists, finding supermassive black holes as early as 500 million years after the Big Bang. That is, however, an issue because the merger and feeding processes that allow black holes to reach masses of millions of billions of times that of the sun should take at least 1 billion years to reach fruition.

Scientists have therefore been eagerly searching for a growth mechanism that could explain how supermassive black holes could exist so early in the universe. Now, one team of researchers theorizes that such cosmic titans could have come about before their time, thanks to changes made to galaxies by energy released by the decay of dark matter.

One suggested mechanism for the early growth of black holes is the direct collapse of vast clouds of gas and dust to immediately form a seed black hole without the time it takes for a massive star to be born, live its life, and then die.

However, that process would still require stars shining on these clouds of matter, providing them with energy — but that's rare. Too rare to explain the abundance of early supermassive black holes seen by JWST. That is, unless there is another energy source to help this process along.

"Our study suggests that decaying dark matter could profoundly reshape the evolution of the first stars and galaxies, with widespread effects across the universe," team leader Yash Aggarwal of the University of California, Riverside, said in a statement. "With the JWST now revealing more supermassive black holes in the early universe, this mechanism may help bridge the gap between theory and observation."

Does dark matter decay?

Dark matter is the mysterious substance that makes up 85% of the matter in the cosmos. It remains so curious because it doesn't interact with light (more accurately, electromagnetic radiation). Not only does this make it effectively invisible, but it also tells scientists that dark matter can't be made up of electrons, neutrons and protons, the particles that compose the atoms that make up stars, planets, moons, our bodies and everything we see around us.

This has spurred the search for particles beyond the Standard Model of particle physics. These hypothetical particles have a range of masses and possible properties. This includes some that pass through each other like ghosts, some that interact with each other, exchanging energy, and others that decay into smaller particles, releasing a tiny bit of energy in the process.

Aggarwal and UCR colleague Flip Tanedo think that it would only take energy equivalent to a billion trillionth of the energy of a single AA battery to "supercharge" primordial gas clouds, with the decay of dark matter capable of providing this.

"The first galaxies are essentially balls of pristine hydrogen gas whose chemistry is incredibly sensitive to atomic-scale energy injection," said Tanedo. "These are the properties that we want for a dark matter detector — the signature of these 'detectors' might be the supermassive black holes that we see today."

The team's work also allowed them to pin down a hypothetical mass range of between 24 and 27 electronvolts for dark matter particles capable of sparking the creation of direct collapse black holes that could give supermassive black hole growth a head start. The team's conclusion stems from a series of very happy coincidences that help them gather the right mix of particle physicists, cosmologists and astrophysicists to formulate a theory of cosmic coincidence.

"We showed that the right dark matter environment can help make the 'coincidence' of direct collapse black holes much more likely," Tanedo said. "In the same way, the support for interdisciplinary work helped make the 'coincidence' leading to this work possible."

The team's research was published on Tuesday (April 14) in the Journal of Cosmology and Astroparticle Physics.

Astronomers watched as jets blasting from a black hole cannibalized a blue supergiant companion star. Data from the Square Kilometre Array Observatory (SKA) radio telescope allowed the team to measure the power of these outbursts, finding them as powerful as the output of 10,000 suns, which could help to reveal how they shape entire galaxies around them.

The system studied by the team is known as Cygnus X-1 (Cyg X-1), located 7,000 light-years away and one of the brightest sources of X-rays in the sky. Cyg X-1 is thought to consist of a stellar-mass black hole estimated to have around 21 times the mass of the sun, which is feeding from a blue supergiant star.

The black hole and its donor star are separated by just 30 million miles (48 million kilometers), which is around 20% of the distance between Earth and the sun (0.2 astronomical units).

The blue supergiant star is supplying the Cyg X-1 black hole with material via powerful stellar winds blowing from it. This matter can't fall straight to the black hole, though, as it has angular momentum, or spin. Instead, it forms a flattened swirling cloud called an accretion disk that gradually feeds the black hole.

The immense gravity of the black hole heats the accretion disk, causing the powerful X-ray emissions associated with Cyg X-1.

Not all of this matter finds its way into the black hole, though. Some is channeled to the poles of the black hole from where it is blasted out as powerful jets. Astronomers were not only able to determine the power of these jets, but also determined that they travel at around 336 million miles per hour (150,000 km/s), about half the speed of light.

Team leader Steve Prabu of the University of Oxford described the movement of the jets in a series of SKA images as them "dancing." This referred to the fact that the Cyg X-1 jets seemed to be getting deflected in different directions as the star and black hole orbited each other. Prabu and colleagues determined that it was the stellar winds blowing from the star pushing on the black hole jets that are powering their "dance."

The findings give scientists a better idea of the amount of energy black hole jets release into their environments.

"A key from this research is that about 10% of the energy released as matter falls in towards the black hole is carried away by the jets," Prabu said. "This is what scientists usually assume in large-scale simulated models of the universe, but it has been hard to confirm by observation until now."

What is even more exciting about this research is that it gives scientists a way to measure the energy of jets blasting from other black holes, including much larger supermassive black holes that sit at the heart of all large galaxies and possess masses millions or billions of times that of the sun.

"Because our theories suggest that the physics around black holes is very similar, we can now use this measurement to anchor our understanding of jets, whether they are from black holes 10 or 10 million times the mass of the sun," team member James Miller Jones of the Curtin Institute of Radio Astronomy (CIRA) said.

"With radio telescope projects such as the Square Kilometre Array Observatory currently under construction in Western Australia and South Africa, we expect to detect jets from black holes in millions of distant galaxies, and the anchor point provided by this new measurement will help calibrate their overall power output.

"Black hole jets provide an important source of feedback to the surrounding environment and are critical to understanding the evolution of galaxies."

The team's research was published on Thursday (April 16) in the journal Nature Astronomy.

Ripples in the very fabric of space and time called "gravitational waves" may have provided the first tantalizing evidence of tiny black holes born during the Big Bang. These primordial black holes could, in turn, account for most if not all of the universe's most mysterious stuff, known as dark matter.

Unlike stellar mass black holes, primordial black holes weren't born when massive stars died, but instead from fluctuations in density that occurred immediately after the birth of the cosmos. That means they can be much smaller than stellar mass black holes, which have at least the same mass as several suns. These Big-Bang-born "non-astrophysical" black holes can have masses as small as that of an average asteroid or as large as a massive planet.

Yet, primordial black holes remain frustratingly hypothetical despite being first proposed by Stephen Hawking in the 1970s. But now, the first potential hint of their existence comes in the form of a gravitational wave signal "heard" last by LIGO (Laser Interferometer Gravitational-Wave Observatory), which indicated a collision between two black holes, at least one of which has a mass smaller than the mass of the sun.

"The most common black holes form as the result of a supernova, the death of a massive star. So, their masses can range from a few times the sun’s mass to billions of solar masses," University of Miami researcher Nico Cappelluti said in a statement. "We believe our study will aid in confirming that they [primordial black holes] actually do exist."

There remains the possibility that the gravitational wave signal mentioned above was a false alarm, the result of interference or "noise" in LIGO's massive interferometer laser arms. However, Cappelluti and his University of Miami colleague, Alberto Magaraggia, believe that the unusual signal couldn't be caused by anything but a primordial black hole.

And they intend to prove it.

"We attempted to estimate how many primordial black holes may exist in the universe and how many of them LIGO should be able to detect, and our results are encouraging," Magaraggia said. "We predict that subsolar black holes like the one LIGO may have observed should indeed be rare, consistent with how infrequently such events have been seen so far.

"The most plausible explanation for the LIGO signal, which lacks any conventional astrophysical explanation, is the detection of a primordial black hole. And our research indicates that these primordial black holes could account for a significant portion, if not all, of dark matter."

Connecting dark matter and primordial black holes

Dark matter is a pressing puzzle for physicists because, despite accounting for 85% of the universe's matter and thus outweighing the "everyday matter" comprising stars, planets, moons, asteroids, our bodies, and everything we see around us by a ratio of five to one, they have no idea what this stuff actually is. That is partially because, unlike the particles that account for that everyday matter, dark matter doesn't interact with electromagnetic radiation, light to you and me. That makes it effectively invisible, with scientists only able to infer the presence of dark matter due to its interaction with gravity and the knock-on effect this has on light and everyday matter.

In fact, the gravitational influence of dark matter is crucial as the gravity of the visible matter in galaxies alone isn't sufficient to hold them together.

The unusual characteristics of dark matter have prompted scientists to search beyond the standard model of particle physics for particles that could comprise it. Thus far, this search has turned up empty-handed. That has led some scientists to postulate that dark matter could be partially or wholly accounted for by primordial black holes. Like all black holes, primordial black holes have mass and thus interact with gravity and are effectively invisible due to the fact that they are bounded by a light-trapping surface called an event horizon. That makes them a good fit for dark matter.

However, as Cappelluti and Magaraggia concede, as convinced as they are that this mystery signal indicates the existence of primordial black holes, a lot more evidence of these non-astrophysical black holes will be needed before they can be firmly connected to dark matter.

With U.S.-based LIGO and its gravitational wave detector partners, Virgo in Italy and KAGRA in Japan, set for sensitivity boosts and a future wealth of highly sensitive gravitational wave detectors such as the space-based LISA (Laser Interferometer Space Antenna), on the horizon, this could be merely a case of waiting for technology to catch up to theory. But that is nothing new. Considering that gravitational waves were first predicted by Einstein in 1915 and the first successful detection was only made 100 years later in 2015, hunting these ripples in spacetime has always been a waiting game requiring a lot of patience.

"LIGO picked up what is very strong evidence that these types of black holes exist. But we’ll need to detect another such signal or even several others to get the smoking-gun confirmation that they are real," Cappelluti said. "But what is clear is that they cannot be excluded as being real."

The team's research has been accepted for publication in the Astrophysical Journal and is available as a preprint on the paper repository arXiv.

Astronomers watched a distant galaxy cut off the "food," or general matter, flowing to its central supermassive black hole. As the regions around feeding black holes are often brighter than the combined light of every star in their host galaxy, this led to a radical change in brightness occurring over just 20 years. The starvation of this central black hole was marked by the galaxy dimming by 95%, dropping to 5% of its original brightness.

The discovery is remarkable because it demonstrates that the activity of supermassive black holes can radically change over timespans similar in scale to a human lifetime — rather than over thousands of years as current models suggest. As the first evidence of this rapid "starvation" the discovery could prompt a change in current black hole feeding models that suggest such changes take much longer to proceed.

While all galaxies are thought to have supermassive black holes with masses millions or even billions of times that of the sun at their hearts, not all of these cosmic titans are actively feeding. For instance, Sagittarius A* (Sgr A*), the supermassive black hole at the heart of the Milky Way, exists on a diet akin to a human eating one grain of rice every one million years.

When supermassive black holes are surrounded by a wealth of gas and dust, their immense gravitational influence causes this disk-shaped structure, called an accretion disk, to glow brightly. This cosmic larder region with a feeding black hole at its heart is called an active galactic nucleus (AGN), and can get so bright it outshines the combined light of every star in the surrounding host galaxy. When the flow of gas to the accretion disk is slowed, and the black hole's larder is not restocked, the AGN's brightness lowers. That is exactly what seems to be happening in this galaxy.

"It is fascinating that an active galactic nucleus can change its brightness so dramatically over such a short period of time, and that this fading appears to be caused by a large change in the accretion rate onto the supermassive black hole," team leader Tomoki Morokuma of Chiba Institute of Technology said in a statement. "Using wide-field survey data, such as those from Hyper Suprime-Cam, we hope to discover more objects like this and learn how the activity of supermassive black holes shuts down and restarts."

Supermassive black hole is put on a strict diet

The international team of astronomers discovered that this black hole in the galaxy J0218−0036 was gradually being starved when they dived into two decades of archival astronomical data and compared images from the Sloan Digital Sky Survey (SDSS) with those from Hyper Suprime-Cam (HSC) on the Subaru Telescope.

This revealed a decline in brightness of 95% over 20 years. This is extreme compared to the usual variability of AGN brightness, which is around 30%. The team continued their investigation of the AGN using observations taken over 70 years, and by collecting new data from this AGN using the Gran Telescopio Canarias (GTC), the Subaru Telescope and the W. M. Keck Observatory, as well as an array of radio telescopes. This allowed them to track changes in brightness over a range of wavelengths from X-rays to infrared radiation.

Following this investigation, the team determined the rate at which gas was flowing from the accretion disk to this supermassive black hole had been cut by around 98% over the course of just seven years. That told the researchers the supply of matter to the accretion disk was rapidly decreasing.

The researchers confirmed this was a case of the food supply of this black hole being staunched, by ruling out the possibility that a cloud of gas had passed in front of the accretion disk, temporarily blocking its light. They determined that such blocking couldn't account for changes across all the different wavelengths of light they studied.

Though the cut in gas supply to this AGN and the end of replenishment of the accretion disk that is gradually feeding this supermassive black hole are certain, what the team can't be completely sure of is what is causing this cessation. Even with that mechanism shrouded in mystery, this research shows that changes in the mass accretion of supermassive black holes don't always take thousands of years, as previously thought.

"This object shows rapid variability that cannot be explained by standard models. It provides an important test case for developing new theoretical models," team member Toshihiro Kawaguchi of the University of Toyama said. "We will investigate what physical conditions could reproduce the observed behavior."

The team's research was published in the journal Publications of the Astronomical Society of Japan (PASJ).

One of the most fundamental and curious mysteries in the universe is the fact that anything exists at all. That is because during the Big Bang, equal amounts of matter and antimatter particles should have been created — antimatter being like the "opposite" of regular matter, meaning it's made up of antiprotons and antielectrons. And when matter and antimatter particles meet, they are mutually annihilated.

That means in a universe split up into matter and antimatter, large structures such as galaxies, stars, planets, moons and even our bodies should struggle to exist. Thus, some early quirk of the universe must have eliminated antimatter and allowed a matter-dominated cosmos to prosper. For some time, scientists have been keenly searching for evidence of what this type of event might be.

Enter Polish theoretical physicist Nikodem Poplawski of the University of New Haven. Poplawski theorizes that the reason the matter and antimatter asymmetry exists is that tiny primordial black holes created during the Big Bang gobbled up vast amounts of antimatter.

"Primordial black holes are hypothetical black holes that formed soon after the Big Bang because of extreme, high-density fluctuations in the early universe. They are good candidates for being the seeds of supermassive black holes at the centers of massive galaxies, as well as of intermediate-mass black holes at the centers of globular clusters," Poplawski told Space.com. "There are other models of elimination of antimatter, but they all assume some physics beyond the Standard Model of particle physics.

"The mass asymmetry between matter and antimatter was surprising, but it immediately suggested to me that it could be a simple and natural cause of the observed matter-antimatter imbalance in the universe."

Was antimatter a drag in the earlier universe?

Poplawski explained how there are also unknown processes that violate the balance between a family of particles called baryons and their antimatter counterparts, the antibaryons.

"The mass asymmetry and the resulting black-hole capture asymmetry produced the matter–antimatter imbalance in the observable universe without violating the conservation of baryon number and invoking new physics beyond the Standard Model," Poplawski explained.

The researcher says that because antimatter particles are more massive than matter particles, during pair production in the early universe, the antimatter particles were slower than the corresponding matter particles.

"Because the probability for gravitational capture of a massive particle by a black hole increases as its speed decreases, the antimatter particles were captured by black holes at larger rates than the corresponding matter particles," Poplawski said. "The missing antimatter fell into primordial black holes and what did not fall was annihilated by matter."

This could explain another problem in cosmology that has become pressing ever since the James Webb Space Telescope (JWST) began spotting supermassive black holes around 500 million years after the Big Bang. This is an issue because the merger and feeding process that allows supermassive black holes to grow to masses of millions, or even billions, of times that of the sun were previously thought to take at least 1 billion years to reach fruition. Seeing supermassive black holes before the universe was 1 billion years old therefore presents a considerable puzzle.

Poplawski thinks that by gobbling up antimatter, primordial black holes could have gotten a head start on these growth processes.

"Primordial black holes consumed more antimatter than matter, and because antimatter was much heavier than matter, primordial black holes enormously increased their masses," he said. "This could possibly explain how supermassive black holes recently observed in the early universe have grown so quickly."

Of course, there is a long way to go before this theory is accepted by the scientific community at large. One thing that could aid in its acceptance is obtaining observational evidence of the existence of primordial black holes, which since they were first proposed by Stephen Hawking in the 1970s, have remained frustratingly hypothetical.

"Primordial black holes would have existed in the very early universe, which is currently very difficult to probe. I hope that gravitational waves and neutrinos could be possibly used in the future to test this hypothesis," Poplawski said. "Also, there could be future experiments testing if matter and antimatter particles may have slightly different masses at higher densities or smaller distances compared to those currently probed. "In fact, some recent experiments showed that mesons and antimesons decay differently. This difference might be related to matter-antimatter mass asymmetry."

Poplawski's research is available on the preprint paper repository arXiv.

The joint NASA and Japan Aerospace Exploration Agency (JAXA) mission XRISM has spotted a monster black hole awakening in a distant "starburst" galaxy.

The research is revolutionary to black hole science, because it represents the first observation of the exact stage at which "winds" from a black hole begin to shape an entire galaxy.

Thus, the "switching on" of this supermassive black hole's powerful outflows could help scientists better understand how these cosmic titans and the intense winds of matter that flow from them influence their home galaxies, and how galaxies and their incumbent and dominant central supermassive black holes evolve in unison.

The team behind this research studied the supermassive black hole IRAS 05189-2524 using XRISM (the X-ray Imaging and Spectroscopy Mission) and its onboard, sophisticated X-ray spectroscopic instruments. This work revealed bullet-like outflows blasting from the black hole's vicinity at speeds up to around 14% the speed of light.

The team found that these black hole bullets carried with them energy 100 times greater than that of slower molecular winds that spread through the distant galaxy, which is the result of a recent merger and is currently in the midst of intense star formation.

The energetic nature of these outflows shows they are more than capable of redirecting the evolution of this galaxy.

Supermassive black holes and galaxies grow up together

when it was created via a merger between two progenitor galaxies. This collision delivered a vast amount of gas and dust, which triggered an intense bout of star formation, referred to as starburst.

However, much of this gas flows toward the heart of the galaxy and its central supermassive black hole, gathering around it in a flattened swirling cloud called an "accretion disk." As the accretion disk gradually feeds the black hole, the huge gravitational influence of the supermassive black hole, estimated to be 420 million times more massive than the sun, generates powerful tidal forces in the accretion disk, causing it to glow brightly.

This region is referred to as an active galactic nucleus (AGN), and its bright emissions are seen on Earth as a quasar.

Not all the matter in the accretion disk is fed to the supermassive black hole, though. Some is channeled to the black hole's poles, from where it is blasted out as powerful jets. Other matter is blown away by intense black hole winds.

These factors can push gas and dust away from the AGN, starving the black hole, and away from the host galaxy as a whole. This has the effect of "killing" the galaxy by cutting off star formation. This leads to a quiet phase in the galaxy, now with a settled elliptical shape, without star formation, and with a slumbering black hole.

IRAS 05189-2524 presents a unique opportunity for scientists to study this process, as it is in the late stages of merging, with an active starburst ongoing and an active supermassive black hole in an AGN.

The scientists not only studied these black hole bullets in great detail but also found that this supermassive black hole is still voraciously feeding. In fact, this violent consumption of matter is close to the theoretical limit for such a black hole. The team expects the outflows of matter from this black hole to intensify, eventually killing star formation in this galaxy.

The researchers hope to further study IRAS 05189-2524 with XRISM, as well as collect observations with the forthcoming NewAthena spacecraft, set to be the largest X-ray observatory ever built.

The new results will soon appear in a special edition of the Astrophysical Journal Letters.

Scientists have discovered that before black holes collide with neutron stars and merge, these extreme stellar remnants can swirl around each other in oval orbits rather than in circular orbits. The revelation demonstrates another way in which black holes and neutron stars push the laws of physics, and casts doubt on assumptions regarding the formation and evolution of these mixed binary systems.

A team of scientists challenged assumptions that black holes and neutron stars approach each other in circular orbits when they studied ripples in spacetime, or gravitational waves, that rang out from just such a "mixed merger." The signal from this merger, dubbed GW200105, was detected by the gravitational wave detectors Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo. The merger occurred around 910 million light-years away, resulting in the creation of a daughter black hole with around 13 times the mass of the sun.

"This discovery gives us vital new clues about how these extreme objects come together," team member Patricia Schmidt, from the University of Birmingham in the UK, said in a statement. "It tells us that our theoretical models are incomplete and raises fresh questions about where in the universe such systems are born."

Key to the team's discovery was a new model of gravitational waves developed at the University of Birmingham’s Institute of Gravitational Wave Astronomy, which allowed Schmidt and colleagues to determine the orbits of the progenitor objects.

This included calculating how much the black hole and neutron star that collided to create this gravitational wave signal were wobbling, or "precessing," before their merger. The calculations revealed a lack of precession prior to the merger.

This marks the first time these characteristics have been measured for a "mixed merger" between a black hole and a neutron star, both of which are stellar remnants created when massive stars "die" and undergo gravitational collapse. The results hint at the influence of an unseen third object in this system.

"The orbit gives the game away. Its elliptical shape just before merger shows this system did not evolve quietly in isolation but was almost certainly shaped by gravitational interactions with other stars, or a third companion," Schmidt continued.

Previously, when a circular orbit had been considered for the progenitor objects beyond this merger, researchers had underestimated the mass of the black hole as being around 9 times the mass of the sun, and the neutron star having a mass of around 2 solar masses.

"This is convincing proof that not all neutron star–black hole pairs share the same origin," team member Gonzalo Morras, from the Universidad Autónoma de Madrid, Spain, said. "The eccentric orbit suggests a birthplace in an environment where many stars interact gravitationally."

The scientists' results indicate that there are likely multiple ways in which black hole-neutron star mergers can proceed, rather than there being one dominant formation channel.

This could help explain why astronomers are increasingly seeing diversity in merging stellar remnant binaries.The team's results were published on Wednesday (March 11) in the Astrophysical Journal Letters.

Our catalog of spacetime ripples "heard" by gravitational wave detectors here on Earth has doubled, scientists say, with newly discovered sources ranging from wobbly black hole mergers to the heaviest black hole collision detected to date.

Back in 1915, Albert Einstein predicted that when the most dense and extreme objects in the universe collide, these events would set the very fabric of space and time (united as a 4-dimensional entity called spacetime) ringing. Then, 100 years later, on Sept. 14, 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) made the first detection of these spacetime ripples — they originated from colliding black holes over 1.3 billion light-years away.

Since then, LIGO and its partner gravitational wave detectors Virgo in Italy and KAGRA (Kamioka Gravitational Wave Detector) in Japan have detected a multitude of gravitational waves from colliding black holes, merging neutron stars, and even the odd "mixed merger" between a black hole and a neutron star. The latest data collection from the LIGO-Virgo-KAGRA (LVK) Collaboration reveals the universe is practically humming with gravitational waves from cosmic collisions.

Each new gravitational-wave detection allows us to unlock another piece of the universe’s puzzle in ways we couldn’t just a decade ago," LVK member Lucy Thomas of the California Institute of Technology (Caltech), said in a statement. "It's incredibly exciting to think about what astrophysical mysteries and surprises we can uncover with future observing runs."

More variety

The data that comprises this catalog, dubbed the Gravitational-Wave Transient Catalog-4.0 (GWTC-4), includes 128 incredibly distant gravitational wave sources. It was collected during the fourth observational run of these gravitational wave detectors, which was conducted between May 2023 and Jan. 2024.

Prior to this, and during the first three observing runs of LIGO, Virgo and KAGRA, scientists had only "heard" 90 potential gravitational wave sources. Excitingly, GWTC-4 could technically have been even larger, as around 170 other gravitational wave detections made by LIGO, Virgo and KAGRA haven't yet made their way into the catalog.

"In the past decade, gravitational wave astronomy has progressed from the first detection to the observation of hundreds of black hole mergers," LIGO spokesperson Stephen Fairhurst, a professor at Cardiff University in the U.K., said in the statement. "These observations enable us to better understand how black holes form from the collapse of massive stars, probe the cosmological evolution of the universe and provide increasingly rigorous confirmations of the theory of general relativity."

One aspect of GWTC-4 that really stands out is the variety of events that created these signals. Within this catalog are gravitational waves from mergers between the heaviest black hole binaries yet, each about 130 times as massive as the sun, lopsided mergers between black holes with seriously mismatched masses, and black holes that are spinning at incredible speeds of around 40% the speed of light. In these cases, scientists think the extreme characteristics of the black holes involved in these mergers are the result of prior collisions, providing evidence of merger chains that explain how some black holes grow to masses billions of times that of the sun.

"This dataset has increased our belief that black holes that collided earlier in the history of the universe could more easily have had larger spins than the ones that collided later," LVK member and MIT scientist Salvatore Vitale said in the statement.

GWTC-4 also includes two new mixed mergers involving black holes and neutron stars.

"The message from this catalog is: We are expanding into new parts of what we call 'parameter space' and a whole new variety of black holes," LVK member Daniel Williams, of the University of Glasgow in the U.K., said in the statement. "We are really pushing the edges, and are seeing things that are more massive, spinning faster, and are more astrophysically interesting and unusual."

The catalog also demonstrates just how sensitive the LVK detectors have become. Some of the neutron star mergers occurred up to 1 billion light-years away, while some of the black hole mergers occurred up to 10 billion light-years away. These detections have allowed scientists to test the theory that first predicted the existence of both black holes and gravitational waves, Einstein's magnum opus theory of gravity, general relativity.

"Black holes are one of the most iconic and mind-bending predictions of general relativity. They shake up space and time more intensely than almost any other process we can imagine observing," LVK member Aaron Zimmerman, of the University of Texas at Austin, said in the statement. "When testing our physical theories, it's good to look at the most extreme situations we can, since this is where our theories are most likely to break down, and where we have the best chance of discovery.

"So far, the theory is passing all our tests. But we’re also learning that we have to make even more accurate predictions to keep up with all the data the universe is giving us."

The LVK results will soon appear in a special edition of the Astrophysical Journal Letters.

Astronomers have used the world's largest and most sensitive low-frequency radio telescope array LOFAR (or Low-Frequency Array), to create the largest radio survey of the cosmos, revealing 13.7 million cosmic objects and events. These include jets erupting from feeding supermassive black holes, colliding galaxies, and supernova explosions that mark the deaths of massive stars and the births of unimaginably dense neutron stars.

The so-called LOFAR Two-meter Sky Survey (LoTSS-DR3) provides an impressive demonstration of how our view of the universe changes when astronomers switch from the wavelengths of light that our eyes have evolved to see to invisible radio waves. As such, LoTSS-DR3 could revolutionize our understanding of the massive jets and associated radio emissions that rip out from active supermassive black holes and our knowledge of how these outflows can shape entire surrounding galaxies.

LoTSS-DR3 doesn't just represent a major breakthrough in radio astronomy; it demonstrates the stunning variety of situations found in systems powered by active supermassive black holes. (The full-scale interactive LoTSS-DR3 map is available to explore here.)

"We can study a diverse population of supermassive black holes and their radio jets at different stages of their evolution, showing how their properties depend not only on the black hole itself, but also on the galaxy and environment in which it resides," Martin Hardcastle of the University of Hertfordshire in the UK said in a statement.

Black hole jets and so much more

Supermassive black holes with masses of millions, or even billions, of times that of the sun are found at the hearts of all large galaxies, but not all of them are defined as being active. When these cosmic titans are surrounded by a swirling cloud of matter called an accretion disk, which gradually feeds them, they are said to sit in a region called an Active Galactic Nucleus (AGN).

The immense gravity of the central supermassive black hole causes the accretion disk to glow brightly across the electromagnetic spectrum. This isn't the only phenomenon that makes AGNs stand out, however.

Black holes are notoriously messy eaters, meaning much of the material that swirls around them isn't fed to them but is rather channeled to their poles by strong magnetic fields. Here, these charged particles are accelerated to near light-speeds and blasted out as parallel twin jets that can stretch out far beyond the limits of the supermassive black hole's host galaxy.

Much of the emissions detected by LOFAR arose from these high-speed particles moving through magnetic fields, generating radio waves. This allowed astronomers to trace supermassive black hole jets, which could be important in understanding how this injection of energy influences the evolution of host galaxies, while also uncovering some of the largest and oldest radio-bright AGNs, also known as radio galaxies.

These emissions weren't limited to supermassive jets, however. The LoTSS-DR3 also traces radio waves from merging galaxies, supernovas and other powerful cosmic events that are capable of accelerating particles to near the speed of light, or "relativistic speeds." One aspect of the universe this approach allowed the team to study was the rates of star birth in millions of galaxies.

"By studying many galaxy clusters, we can show that giant shocks and turbulence drive particle acceleration and strengthen magnetic fields across millions of light-years, something we now see to be happening far more than previously anticipated," team member Andrea Botteon of Italy's National Institute for Astrophysics (INAF) said in the statement.

Closer to home, the LOFAR data also revealed previously hidden aspects of the Milky Way.

"This new data set also provides a unique view of magnetic fields in our Milky Way galaxy," team member Marijke Haverkorn of Radboud University said. "As we are located inside the Milky Way, we need data in large parts of the sky to map out these magnetic fields. LOFAR's unique wavelength range allows us to do that with unprecedented accuracy."

LoTSS-DR3 also revealed radio emissions that seem to arise from interactions between extrasolar planets, exoplanets and their host stars.

The team now plans to build upon LoTSS-DR3, an endeavor that will benefit from the upcoming upgrade to LOFAR. It is hoped that the upgraded LOFAR 2.0 will have twice the survey speed of the current instrument, which, coupled with improved data processing, should lead to vastly improved high-resolution data.

"LoTSS-DR3 is not an endpoint, but a major milestone," Square Kilometer Array Observatory scientist Wendy Williams said. "New facilities such as LOFAR 2.0 will allow us to map the radio universe with even greater sensitivity and resolution, extending the legacy of this survey well into the future."

The team's results are published in the journal Astronomy & Astrophysics.

Two supermassive black holes on a dizzying death spiral could soon become visible to astronomers after researchers worked out how, while rotating around each other, these dark, massive behemoths could gravitationally lens the stars behind them.

Pretty much every large galaxy hosts a supermassive black hole, ranging in mass from millions of times that of our sun (for example the black hole in our Milky Way galaxy, Sagittarius A*) to billions of solar masses. Ordinarily, galaxies have just one supermassive black hole at their hearts, but when two galaxies merge, their black holes can fall towards each other, eventually coming into each other's orbit and, long after that happens, merging in a burst of gravitational waves.

So far, the only binary supermassive black holes that astronomers have identified are widely separated by hundreds or thousands of light-years. For the future, the European Space Agency has planned a space-based gravitational-wave detector called LISA, the Laser Interferometer Space Antenna, to detect the low frequency gravitational waves emitted by merging supermassive black hole binaries. Chinese scientists have also proposed a similar mission called TianQin. But there has been no other known way of spotting such binaries — until now, perhaps.

"The prospect of identifying in-spiraling supermassive black hole binaries years before future space-based gravitational-wave detectors come online is extremely exciting," said Bence Kocsis of the University of Oxford in a statement. "It opens the door to true multi-messenger studies of black holes, allowing us to test gravity and black-hole physics in entirely new ways."

Kocsis is part of a team of astronomers from Oxford and the Max Planck Institute for Gravitational Physics in Germany who have shown how gravitational lensing by binary black holes can reveal their presence in distant galaxies.

Gravitational lensing is a phenomenon caused by massive objects bending the fabric space-time around them due to the impact of their gravitational pull, altering the path of light moving along this warped fabric such that background objects can appear magnified, or sometimes even split into multiple images.

When there is just a single black hole, a background star has to be perfectly aligned with it in order to be lensed. However, for a binary black hole, the situation changes.

"The chances of starlight being hugely amplified increases enormously for a binary compared to a single black hole," said Kocsis.

A binary black hole acts like a pair of rotating lenses, as the black holes orbit their common center of mass. This produces a diamond-shape zone of quasi-periodic lensing events called the 'caustic curve', and along this curve, the lensing is amplified in intensity.

The result is that background stars aligned with the caustic curve will periodically appear to flash, as their light is amplified on timescales of several years corresponding to the orbital period of the black holes. We probably will not even see the star at other times, so distant are the galaxies hosting binary supermassive black holes.

"As the binary moves, the caustic curve rotates and changes shape, sweeping across a large volume of stars behind it," said Hanxi Wang, a Ph.D. student at Oxford, in the statement. "If a bright star lies within this region, it can produce an extraordinarily bright flash each time the caustic passes over it. This leads to repeating bursts of starlight, which provide a clear and distinctive signature of a supermassive black-hole binary."

However, this situation doesn't remain unchanged forever, because the orbits of the black holes are shrinking.

The black holes lose orbital energy to each other, and this energy is transported away as gravitational waves. As they get closer to each other, the black holes begin to orbit faster and faster. It takes millions of years for two black holes to lose enough orbital energy for them to merge, but this shortening of their orbits could become apparent in changes to the caustic curve. These changes would modify the modulation of the frequency of the lensing events and their peak brightness. The mass of the two black holes could also be encoded into the caustic curve.

The modulation to the frequency and peak brightness of the lensing events would take thousands or millions of years to become noticeable. At best, astronomers can only take a snapshot of any given binary supermassive black hole system. However, observe enough similar systems at different stages in their orbital evolution and the snapshots could be put together to tell a larger story.

Fortunately, the forthcoming detailed surveys of the night sky by the Vera C. Rubin Observatory in Chile and the Nancy Grace Roman Space Telescope that is set for launch in 2027 should be powerful enough to spot many lensing events from binary supermassive black holes in faraway galaxies. Then, when it is operational, hopefully some time in the 2030s, LISA could partner with the survey telescopes to perform a detailed multi-messenger (electromagnetic waves and gravitational waves) census of black holes in the universe that are spiraling to an inevitable merger.

The research was published on Feb. 12 in the journal Physical Review Letters.

Scientists have dived deeper into the "eye of the storm" swirling around supermassive black holes than ever before. This unprecedented investigation of the turbulent and violent conditions around these cosmic titans, including the first black hole ever imaged by humanity, was possible thanks to the joint Japanese Aerospace Agency (JAXA)/ NASA X-Ray Imaging and Spectroscopy Mission (XRISM).

Using XRISM, astronomers have seen samples of supermassive black holes influencing the surrounding gas in prior X-ray images, but these were lacking as static images of an incredibly dynamic process. By measuring the energy of X-rays coming from hot gas, XRISM presents a much more dynamic picture of black hole influence than has been available before.

"It's as though each supermassive black hole sits in the 'eye of its own storm.' Before XRISM, it was like we could see a picture of the storm. Now we can measure the speed of the cyclone," team member Annie Heinrich of the University of Chicago said in a statement. "For the first time, we can directly measure the kinetic energy of the gas stirred by the black hole."

Crucial to this study, released at the end of Jan 2026 in Nature, was XRISM, which was launched in 2023. XRISM, operated in partnership with the European Space Agency (ESA), has the ability to track the chemical signature of blisteringly hot gas around supermassive black holes, determining its motion.

"XRISM allows us to unambiguously distinguish gas motions powered by the black hole from those driven by other cosmic processes, which has previously been impossible to do," team co-leader Congyao Zhang of Masaryk University said.

Supermassive black holes are messy eaters

Supermassive black holes with masses of millions or even billions of times that of the sun are thought to sit at the heart of all galaxies. Their immense gravitational influence churns gas, dust, and even proximate stars around them, thus exerting a tremendous influence on their host galaxies.

Supermassive black holes are often surrounded by vast amounts of gas and dust swirling around them in flattened clouds called accretion disks. These disks gradually feed matter to the central black hole, but a great deal of this matter is channelled to the poles of the black hole by powerful magnetic fields, where these particles are accelerated to near light-speed and blasted out as twin jets.

The fact that supermassive black holes are such messy eaters means they don't just churn gas in their vicinity, but also inject vast amounts of energy into their surroundings. This influence stretches far beyond the immediate vicinity of the supermassive black hole, reaching out for hundreds of thousands of light-years. This can influence galaxies in a variety of ways, including "killing" active star formation by forcing out gas, which serves as the building blocks for new stellar objects. Thus, understanding the impact of black holes on their home galaxies is vital for understanding galactic evolution.

Investigations such as this one are crucial to understanding the complete picture of this influence.

One of the supermassive black holes investigated by this team will be very familiar to astronomy fans. In 2019, the general public learned that M87*, located in the galaxy Messier 87 (M87), which itself sits in the Virgo Cluster, had become the first black hole to be imaged by humanity thanks to the Event Horizon Telescope (EHT).

In this recent study, XRISM zoomed into a relatively small region around M87*, discovering the strongest turbulence ever seen in a galaxy cluster, even more violent than the conditions generated when galaxy clusters collide and merge.

"The velocities are high closest to the black hole, and drop off very quickly further away," team member and University of Chicago researcher Hannah McCall said. "The fastest motions are likely due to a combination of eddies of turbulence and a shockwave of outflowing gas, both a product of the black hole."

The team also investigated the motion of gas in the Perseus Cluster of galaxies, the brightest cluster in X-rays as seen from Earth. The brightness of this cluster allowed researchers to use XRISM data to map the motion of gas both around the center of the cluster and further out from its heart.

This revealed the "kick" delivered to the velocity of this gas by a supermassive black hole, as well as the motion of gas being driven by an ongoing merger between Perseus and a chain of galaxies.

This could answer the question of why stars aren't as densely packed into the cores of galaxy clusters as astronomers expect. The team theorizes that if the energy of the moving gas they tracked with XRISM was converted to heat, then this would prevent gas clouds from cooling enough to collapse and birth stars.

"It remains an open question whether this is the only heating process at work, but the results make it clear that turbulence is a necessary component of the energy exchange between supermassive black holes and their environments," McCall said.

XRISM continues to gather X-ray data that could provide an even clearer picture of the relationship between supermassive black holes and their home galaxies, as well as how this relationship changes as both age and evolve.

"Based on what we've already learned, I am positive we are getting closer to solving some of these puzzles," team member Irina Zhuravleva of the University of Chicago said.

Scientists have long suspected that active supermassive black holes can kill their own host galaxies, but new research suggests these cosmic titans are more like serial killers that can extend their murderous rampage across many light-years and destroy neighboring galaxies, too.

For scientists, "death" for a galaxy means the curtailing of star formation. Supermassive black holes are known to cause this when they are actively feeding, as they heat their larder of gas and dust, provoking that matter content to emit powerful radiation. This radiation either pushes away gas, the building blocks of stars — thereby starving the galaxies and black holes themselves — or simply heats that gas and prevents it from cooling enough to collapse and birth a stellar body. Both outcomes can slow or even stop star formation.

"Traditionally, people have thought that because galaxies are so far apart, they evolve largely on their own," team leader Yongda Zhu of the University of Arizona said in a statement. "But we found that a very active, supermassive black hole in one galaxy can affect other galaxies across millions of light-years, suggesting that galaxy evolution may be more of a group effort."

Zhu and colleagues point out that this influence suggests the existence of a "galactic ecosystem" akin to the linked ecosystems of Earth in which changes in one region can deeply impact conditions in another.

"An active supermassive black hole is like a hungry predator dominating the ecosystem," he said. "Simply put, it swallows up matter and influences how stars in nearby galaxies grow."

There goes the neighborhood!

Though supermassive black holes with masses of millions or even billions of times that of the sun are thought to dwell at the hearts of all large galaxies, not all of these objects are cosmic killers. For instance, Sagittarius A* (Sgr A*) at the heart of the Milky Way may once have quenched star formation in our galaxy, but today it is quiet, existing on a diet equivalent to a human eating one grain of rice every million years.

Active supermassive black holes greedily feast on matter from a surrounding swirling cloud called an accretion disk. Their immense gravity generates tidal forces in this accretion disk that cause intense friction, resulting in high temperatures that cause this region to brightly glow across the electromagnetic spectrum. This turbulent region, an Active Galactic Nucleus (AGN), can be seen from across the cosmos as a phenomenon known as a "quasar," often outshining the combined light of every star in its host galaxy.

Not all of the matter in an accretion disk is channeled to the black hole, however. Some matter is channeled to the poles of the supermassive black hole from where it is blasted out as parallel twin jets travelling at near light-speeds. These jets can stretch out far beyond the limits of the galaxy that hosts the active supermassive black hole.

It is little wonder, given the intense radiation of the accretion disk and the violent outflows represented by these twin jets, that active supermassive black holes have a powerful influence over the evolution of their host galaxies.

Since the James Webb Space Telescope (JWST) began investigating the cosmos, a curious pattern has emerged regarding quasars. The more massive and powerful these active supermassive black holes are, the less they seem to be surrounded by neighboring galaxies. That's curious because large galaxies are usually found clustered together, not in isolation.

"We were puzzled," Zhu explained. "Was the expensive JWST broken?" he added with a laugh. "Then we realized the galaxies might actually be there, but difficult to detect because their very recent star formation was suppressed."

Zhu and colleagues began to suspect that bright quasars may not just be dampening star formation in their own galactic backyards; they may be disturbing the neighbors, too.

To investigate the possibility of active supermassive black holes killing star formation in neighboring galaxies, the team set about studying one of the brightest quasars ever seen, J0100+2802. This quasar existed when the universe was less than 1 billion years old, and its central engine is a supermassive black hole with around 12 billion times the mass of the sun.

Using the JWST, the scientists hunted for traces of ionized oxygen in the galaxies around J0100+2802, which is a sign of recent star formation. They found this tracer of star birth was much scarcer in galaxies within a million light-years of the powerful quasar than in galaxies outside that radius. That hints at squashed star formation in these proximate galaxies.

"Black holes are known to 'eat' a lot of stuff, but during the active eating process and in their luminous quasar form, they also emit very strong radiation. The intense heat and radiation split the molecular hydrogen that makes up vast, interstellar gas clouds, quenching its potential to accumulate and turn into new stars," Zhu said. "For the first time, we have evidence that this radiation impacts the universe on an intergalactic scale.

"Quasars don't just suppress stars in their host galaxies, but also in nearby galaxies within a radius of at least a million light-years."

The team now intends to look for this effect in other so-called quasar fields to develop a clearer picture of how supermassive black holes influence their cosmic neighborhoods.

"Understanding how galaxies influenced one another in the early universe helps us better understand how our own galaxy came to be," Zhu said. "Now we realize that supermassive black holes may have played a much larger role in galaxy evolution than we once thought — acting as cosmic predators, influencing the growth of stars in nearby galaxies during the early universe."

The team's results were published on Dec. 3, 2025 in The Astrophysical Journal Letters.

Using NASA's Hubble Space Telescope and Chandra X-ray Observatory, astronomers have hunted for "wandering" black holes drifting through dwarf galaxies. The discovery of these rogue black holes in such small galaxies could provide a "fossil record" that helps to explain how supermassive black holes grew to masses of millions or even billions of times that of the sun.

Supermassive black holes are found at the heart of all large galaxies, and the James Webb Space Telescope (JWST) has increasingly been discovering these cosmic titans already in place when the cosmos was less than 1 billion years old. That is problematic because the merger and feeding processes that are thought to explain supermassive black hole growth should take over 1 billion years to reach fruition. One possible explanation for this is that the process that spawns supermassive black holes may kick off with so-called "black hole seeds" that give a head start to these growth processes. These seeds, classified as either "heavy" or "light," have proved elusive in galaxies in the early universe.

However, models of these black hole seeds predict that their signatures should be visible in dwarf galaxies in the local universe with total stellar masses of billions of times that of the sun. These dwarf galaxies provide a unique laboratory for studying black hole formation and early evolution, thanks to their relatively quiet merger histories compared to those of massive galaxies. This means they can provide a "fossil record" of the original black hole seeds via their non-central intermediate black holes.

In massive galaxies, central supermassive black holes can be quiet, like the Milky Way's supermassive black hole Sagittarius A* (Sgr A*), or they can be ravenously feeding on surrounding gas and dust, creating a violent and turbulent environment which astronomers call an Active Galactic Nucleus (AGN). These AGNs are bright, emitting light across the electromagnetic spectrum.

The team behind this investigation points out that the vast majority of black holes found in dwarf galaxies are accreting (gaining material and mass) and have been identified as dwelling in AGNs.

"Compared to more massive galaxies, dwarf galaxies can have lower central stellar densities and more irregularly shaped potential wells," team leader Megan R. Sturm of Montana State University told Space.com. "As a result, if a black hole forms in the outer reaches of its host galaxy, it is unlikely to ever spiral down into the center. Some researchers have even predicted that approximately half of all black holes in dwarf galaxies are wandering.

"If this is the case, all-sky surveys pointed at the centers of galaxies may simply be missing a large population of dwarf galaxies hosting massive black holes. This has important implications for black hole fraction in this mass range and, therefore, black hole formation through seeding."

Seeing off-center AGNs in a different light

The problem with detecting wandering black holes in these small galaxies is the fact that these dwarf galaxy AGNs have to be distinguished from other radiation sources, such as regions of intense star formation or "starbursts," and from supernova explosions. This can be done by investigating these regions in several different wavelengths of light.

"Observing massive black holes in the dwarf regime can be a complicated process. Since the maximum luminosity of an AGN is proportional to its mass, AGNs in dwarf galaxies are generally dimmer than their higher mass counterparts," Sturm said. "Additionally, low-luminosity/ low-mass AGNs can lack a traditional broad line region or have broad lines that are weak and hard to detect. This makes them both harder to see and easier to confuse with other stellar objects or star-formation-related processes."

This team used Chandra and Hubble to study 12 dwarf galaxies in which AGNs had previously been detected in radio waves. Eight of these AGNs appeared to be offset from the centers of their dwarf galaxy-hosts, or "non-nuclear," indicating they could harbor wandering black holes.

"Generally, supermassive black holes reside in the nucleus of massive galaxies. However, eight of the dwarf galaxies in our sample displayed compact radio emission originating from outside of the optical nucleus of the galaxy, offset by around one to two kiloparsecs [one kiloparsec is around 3,262 light-years] and in some cases outside of the host galaxy entirely," Sturm said. "These are potentially 'wandering' black hole candidates. While these wandering AGN candidates had been observed at radio frequencies, obtaining AGN-like observations at optical or X-ray wavelengths would confirm the presence of an AGN."

Sturm explained that she and her colleagues were able to detect one of these sources, designated ID 64, in optical light with Hubble and in X-rays with Chandra. However, this revealed that it is actually a much more distant AGN that simply aligns with this dwarf galaxy from our perspective.

"Seven galaxies in our sample do not have significantly detected optical/X-ray counterparts. However, it remains a possibility that these are wandering black holes that are either isolated or residing within globular or nuclear star clusters that are simply below our Hubble detection limits," she continued. "It also remains a possibility that they are background, high-redshift interlopers that happen to overlap with our galaxies in the sky, such as the case for ID 64."

Determining if these seven galaxies do indeed host wandering black holes or if these radio signals are the result of more distant AGNs could involve enlisting the help of the JWST, the $10 billion space telescope sibling of Hubble.

"Identifying the origin of the off-nuclear radio sources for the remaining seven wandering black hole candidates may be possible with the exquisite capabilities of the JWST," Sturm said. "With higher resolution, JWST could potentially observe the source of the compact radio emission, whether it be the core of a disrupted dwarf galaxy/star cluster within the host galaxy or a background, high-redshift galaxy."

The team's results are published in the Astrophysical Journal.

This article was originally published at The Conversation. The publication contributed the article to Space.com's Expert Voices: Op-Ed & Insights.

Last year, astronomers were fascinated by a runaway asteroid passing through our solar system from somewhere far beyond. It was moving at around 68 kilometres per second, just over double Earth's speed around the sun.

Imagine if it had been something much bigger and faster: a black hole travelling at more like 3,000km per second. We wouldn’t see it coming until its intense gravitational forces started knocking around the orbits of the outer planets.

This may sound a bit ridiculous – but in the past year several lines of evidence have come together to show such a visitor is not impossible. Astronomers have seen clear signs of runaway supermassive black holes tearing through other galaxies, and have uncovered evidence that smaller, undetectable runaways are probably out there too.

Runaway black holes: the theory

The story begins in the 1960s, when New Zealand mathematician Roy Kerr found a solution of Einstein's general relativity equations that described spinning black holes. This led to two crucial discoveries about black holes.

First, the "no-hair theorem", which tells us black holes can be distinguished only by three properties: their mass, their spin and their electric charge.

For the second we need to think about Einstein's famous formula E = mc ² which says that energy has mass. In the case of a black hole, Kerr's solution tells us that as much as 29% of a black hole's mass can be in the form of rotational energy.

English physicist Roger Penrose deduced 50 years ago that this rotational energy of black holes can be released. A spinning black hole is like a battery capable of releasing vast amounts of spin energy.

A black hole can contain about 100 times more extractable energy than a star of the same mass. If a pair of black holes coalesce into one, much of that vast energy can be released in a few seconds.

It took two decades of painstaking supercomputer calculations to understand what happens when two spinning black holes collide and coalesce, creating gravitational waves. Depending on how the black holes are spinning, the gravitational wave energy can be released much more strongly in one direction than others – which sends the black holes shooting like a rocket in the opposite direction.

If the spins of the two colliding black holes are aligned the right way, the final black hole can be rocket-powered to speeds of thousands of kilometres per second.

Learning from real black holes

All that was theory, until the LIGO and Virgo gravitational wave observatories began detecting the whoops and chirps of gravitational waves given off by pairs of colliding black holes in 2015.

One of the most exciting discoveries was of black hole "ringdowns": a tuning fork-like ringing of newly formed black holes that tells us about their spin. The faster they spin, the longer they ring.

Better and better observations of coalescing black holes revealed that some pairs of black holes had randomly oriented spin axes, and that many of them had very large spin energy.

All this suggested runaway black holes were a real possibility. Moving at 1% of light speed, their trajectories through space would not follow the curved orbits of stars in galaxies, but rather would be almost straight.

Runaway black holes spotted in the wild

This brings us to the final step in our sequence: the actual discovery of runaway black holes.

It is difficult to search for relatively small runaway black holes. But a runaway black hole of a million or billion solar masses will create huge disruptions to the stars and gas around it as it travels through a galaxy.

They are predicted to leave contrails of stars in their wake, forming from interstellar gas in the same way contrails of cloud form in the wake of a jet plane. Stars form from collapsing gas and dust attracted to the passing black hole. It’s a process that would last for tens of millions of years as the runaway black hole crosses a galaxy.

In 2025, several papers showed images of surprisingly straight streaks of stars within galaxies such as the image below. These seem to be convincing evidence for runaway black holes.

One paper, led by Yale astronomer Pieter van Dokkum, describes a very distant galaxy imaged by the James Webb telescope with a surprisingly bright contrail 200,000 light years long. The contrail showed the pressure effects expected from the gravitational compression of gas as a black hole passes: in this case it suggests a black hole with a mass 10 million times the sun's, travelling at almost 1,000km/s.

Another describes a long straight contrail cutting across a galaxy called NGC3627. This one is likely caused by a black hole of about 2 million times the mass of the sun, travelling at 300km/s. Its contrail is about 25,000 light years long.

If these extremely massive runaways exist, so too should their smaller cousins because gravitational wave observations suggest that some of them come together with the opposing spins needed to create powerful kicks. The speeds are easily fast enough for them to travel between galaxies.

So runaway black holes tearing through and between galaxies are a new ingredient of our remarkable universe. It's not impossible that one could turn up in our solar system, with potentially catastrophic results.

We should not lose sleep over this discovery. The odds are minuscule. It is just another way that the story of our universe has become a little bit richer and a bit more exciting than it was before.

Astronomers have discovered that an unusual optical flare is the result of a star being ripped apart and devoured by a black hole — and what really sets this so-called Tidal Disruption Event (TDE) apart is the fact that the black hole involved seems to be an example of an elusive "intermediate mass black hole," a class of this object that has challenged astronomers for decades.

TDEs generally occur when stars venture too close to the supermassive black holes that sit at the heart of large galaxies, resulting in the immense gravity of these cosmic titans simultaneously squashing the stellar body horizontally while stretching it vertically. This "spaghettification" creates a stellar noodle wrapping around the black hole. Some of the remains are fed to the central black hole, while much of it is blasted away at near-light speeds as high-energy jets. These events can take hundreds of days or even years to fade.

This optical flare, designated AT2022zod, was spotted in October 2022 and lasted just over a month. It was traced to the galaxy SDSS J105602.80+561214.7, located around 1.5 billion light-years away from Earth. What was intriguing about this was the fact that the TDE occurred around 10,000 light-years away from the center of this galaxy, where its supermassive black hole dwells. That was the first hint this was the work not of a central supermassive black hole, but of a non-central intermediate mass black hole.

"AT2022zod has the characteristics of a TDE, a flare we observe when a star is ripped apart by interacting with a black hole. These events are, in general, not common, but since we expect a supermassive black hole in the center of almost every galaxy, TDEs are expected to be observed in the center of their host galaxy," team leader Kristen Dage of Curtin University, Australia, told Space.com. "However, AT2022zod is slightly off-nuclear, and very short in comparison with previously observed TDEs, while still highly energetic."

When observed at distances as great as this, TDEs generally last for hundreds of days, making AT2022zod's month-long duration from Oct. 13 to Nov. 18 highly unusual. "The combination of being hosted by an elliptical galaxy, famously home to large populations of star clusters, while being off-nuclear and of short duration, made us intrigued that this may be one of the elusive intermediate mass black holes that might exist outside the center of the galaxy, and more importantly, open a new avenue to search for and study them," Dage continued.

Intermediate black holes as cosmic middle men

Supermassive black holes are thought to have masses millions or billions of times that of the sun, while stellar mass black holes, which form from dying massive stars, are thought to have masses from three to many hundreds of times the mass of the sun. That leaves a huge mass range between these two types of black holes in which the aptly named intermediate mass black holes are thought to sit.

Because supermassive black holes are thought to grow via merger chains between increasingly massive black holes, it is reasonable to presume that intermediate mass black holes play a key role in this growth process. That means black holes in this mass range should be fairly ubiquitous in the cosmos, yet astronomers have had a really tough time discovering them.

"I think it's really difficult to overstate how bad we are at finding intermediate mass black holes. We are excellent at finding supermassive black holes, and thanks to LIGO-Virgo-Kagra gravitational wave detectors, we are getting better at finding stellar mass black holes, but I could count on my hands the number of intermediate mass black hole candidates that have reached some kind of consensus within the astronomical community," Dage said. "Up to this point, TDEs from intermediate black holes are known to exist, but are very difficult to observe. They are most of the time overshadowed by other activities within the galaxy's central region."

Astronomers can distinguish between TDEs caused by intermediate black holes and those generated when supermassive black holes rip up stars due to the location they occur and the duration of these events.

"With our current understanding of TDE behavior, we know that event duration scales as black hole mass, so all other things being equal, shorter timescale points to lower mass black holes," Dage said. "What sold me on AT2022zod being special was when I compared it to other TDEs at similar distances or with similar host galaxies, and it didn't fit in with the same behavior."

The discovery of this off-center TDE could also reveal more about the environment occupied by this intermediate-mass black hole. For instance, it is pretty evident that TDEs are much more likely to occur in regions in which stars are densely packed together. "If you're not in some kind of star cluster, generally the host galaxy's central nuclear star cluster, then you're just not going to have a TDE, because the odds of a given star waltzing in near the black hole are too low," Dage said. This stellar density is found at the heart of galaxies, but there are also non-central regions of galaxies in which stars are also jammed together tightly.

Failed supermassive black holes?

The team theorizes that this TDE occurred in a globular cluster or an ultracompact dwarf galaxy (UCD) within SDSS J105602.80+561214.7 itself. Both globular clusters and UCDs are densely packed conglomerations of ancient stars reaching the end of their lives.

"These systems are basically black hole factories, and their crowded and dynamical systems provide opportunities for black holes to merge and grow into the intermediate mass range, particularly through runaway stellar collisions," Dage said. "When you combine this with the observational evidence for kinematic studies of black holes in UCDs, it makes them very compelling environments to host intermediate mass black holes!"

The origins of UCDs are currently shrouded in mystery. These dense stellar regions could arise when two globular clusters are drawn together, collide and merge, or UCDs may be dwarf galaxies that have been stripped of their outer stars, leaving them as a compact and dense stripped galactic nucleus.

"These two different formation scenarios have very different implications for the black hole evolution. If they are stripped nuclei, then they are 'failed' supermassive black holes, with a similar formation pathway to the supermassive black holes and large galaxies," Dage explained. "If they're just big globular clusters, then things could be completely different, and dynamics play a vital role in black hole formation and evolution."

Dage said scientists know elliptical galaxies host both globular cluster stellar systems and UCDs, but in this case, the host galaxy is so far away that the team can't quite disentangle the nature of the actual environment of AT2022zod. "We just know it's in some kind of star cluster," Dage said. "I personally would love it if it were in a globular cluster, but from what we know of more nearby systems, a UCD makes a lot of sense as a host in the nearby universe."

She added that many studies of the physics of UCDs show they host black holes in the mass range estimated for AT2022zod. This includes a system in the Milky Way called Omega Centauri, although Dage pointed out there is still some debate about whether this densely packed star cluster in our galaxy is a UCD or a globular cluster.

While the environment of the TDE AT2022zod may remain a mystery for the foreseeable future, the team's research could provide a much-needed roadmap for discovering intermediate black holes, which will become especially relevant when the Vera C. Rubin Observatory begins conducting its decade-long Legacy Survey of Space and Time (LSST).

"Rubin is poised to make such a huge impact — it will provide incredibly sensitive 10-year optical coverage of millions of star clusters within 330 million light-years, and ought to be sensitive to populations of TDEs hosted by dense stellar environments," Dage concluded. "We just need to make sure we are looking in the right places, can do prompt follow-up to better understand the physics and the host system, and be able to interpret what we see."

The team's results are available on the paper repository site arXiv.

When the beacons were lit in "The Lord of the Rings: The Return of the King," the city of Gondor called to Rohan for aid, spelling doom for Sauron and his legions. However, when the beacons of supermassive black hole systems named for these locations in J.R.R. Tolkien's "Lord of the Rings" novels were lit up, it was exceptionally good news for scientists.

The supermassive black hole binaries Gondor, officially designated SDSS J0729+4008, and Rohan, SDSS J1536+0411, were discovered by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) using a new technique that uses the background hum of ripples in space called "gravitational waves" in conjunction with observations of quasars, which are powered by feeding supermassive black holes.

The logic behind this is that supermassive black hole binaries, which spiral together to lead to collisions and mergers, emit gravitational waves of increasing frequency as their orbits shrink, creating a background hum of gravitational waves. The resultant mergers seem to be five times more likely to be found in quasars.

That makes quasars beacons that can indicate the unification of supermassive black holes. If one of these beacons radiates gravitational waves like the lit beacons of Gondor, it indicates binary black holes are present. Thus, this detection technique offers scientists a method to create a cosmic map of these merging titans.

"Our finding provides the scientific community with the first concrete benchmarks for developing and testing detection protocols for individual, continuous gravitational wave sources," NANOGrav team member Chiara Mingarelli said in a statement.

Mingarelli and colleagues hunted for supermassive black hole binaries using their new approach in 114 Active Galactic Nuclei (AGNs), the bright central regions of galaxies where supermassive black holes are ravenously feasting on surrounding gas and dust.

Mingarelli explained the reason for the unusual name choice for these black hole systems: "The names come from both people and pop culture. Rohan was first, for Rohan Shivakumar, the Yale student who first analyzed it, and Gondor was next, because, well — the beacons were lit!"

NANOGrav, which first detected a gravitational wave background in 2023, will spend the coming months hunting and identifying supermassive black hole binaries. The team thinks that even a relatively small catalog of black hole mergers could help create a gravitational wave background map. This research could also help scientists better understand galaxy mergers, the physics of black holes and the nature of gravitational waves themselves.

"Our work has laid out a roadmap for a systemic supermassive black hole binary detection framework," Mingarelli said. "We carried out a systematic, targeted search, developed a rigorous protocol — and two targets rose to the top as examples motivating follow-up."

The team's results were published on Feb. 5 in The Astrophysical Journal Letters.

Astronomers may have witnessed the birth of a brand-new black hole in our neighboring galaxy, offering one of the clearest glimpses yet of how some stars quietly collapse into these cosmic abysses without the usual fireworks of an explosion.

While scouring archival data from NASA's NEOWISE mission, a team led by Columbia University astronomer Kishalay De discovered that one of the brightest stars in the Andromeda Galaxy mysteriously brightened over a decade ago, faded dramatically and then vanished from view. The star, labeled M31-2014-DS1, lay about 2.5 million light-years from Earth and weighed just 13 times the mass of our sun — relatively lightweight by typical black hole-forming standards, according to De and colleagues' research.

"Observations like these are starting to finally change this long-held paradigm that it's only the very massive stars that turn into black holes," De told Space.com.

If this detection holds up, he added, "then it really means that there are many more black holes out there than what we've anticipated so far."

Before it vanished, the star shone roughly 100,000 times brighter than our sun. De likened its prominence to Betelgeuse, a well-studied red supergiant that marks the right shoulder of the constellation Orion.

If Betelgeuse were to fade from the sky over a few years, De said, "that would really be shocking and disturbing for us here on Earth, because suddenly Orion wouldn't look the way it does."

De and his team first noticed M31-2014-DS1's strange behavior in data from the NEOWISE mission. Around 2014, the team's new paper reports, the star brightened in infrared light, then began dimming sharply in 2016, and by 2023 had effectively vanished — fading to roughly one ten-thousandth of its original brightness.

De said he was sitting in front of a computer at the Keck Observatory in Hawaii in 2023, collecting follow-up observations of the star when he noticed something did not add up.

"I remember the moment when we pointed the telescope towards this star — except the star was not there at all," he recalled. Additional observations from the Hubble Space Telescope and other ground-based observatories confirmed that the star was truly gone. "That's when it clicked," De said. "Stars that are this bright, this massive, do not just randomly disappear into darkness."

According to a leading theory, black holes form when massive stars exhaust their nuclear fuel, triggering an explosive supernova that blasts the star's outer layers into space that leaves behind either a dense neutron star or a black hole. M31-2014-DS1, however, appears to have formed a black hole without any such fireworks.

"Ten years ago, if someone said a 13 solar-mass star would turn into a black hole, nobody would believe that," De said. "It was completely outside what was considered the norm."

De and his colleagues suspect M31-2014-DS1's small, densely packed core collapsed into a black hole in a matter of hours. What astronomers can still see is not the star itself, but a faint glow in infrared light produced by leftover dust and gas swirling around the newborn black hole.

That material is moving too fast to fall straight in, said De, instead forming a rotating disk that slowly feeds the black hole over time — much like water swirling around a bathtub drain before finally slipping down. Over the next few decades, the infrared signal is expected to fade steadily as more of the remaining debris spirals inward and disappears.

Because the Andromeda Galaxy is relatively close in cosmic terms, the fading debris should remain visible to powerful observatories such as the James Webb Space Telescope (JWST), De said. But directly imaging the black hole itself — as the Event Horizon Telescope has done for much larger black holes — is not possible in this case, at least with current technology, given the object's small size.

Last year, the team gathered additional data from JWST, whose powerful infrared vision revealed that the black hole remains heavily shrouded in the star's outer material, according to a preprint posted on arXiv on Jan. 9.

To further test their conclusion, the researchers also used NASA's Chandra X-ray Observatory to search for high-energy radiation expected from hot gas near the black hole. No X-rays were detected, but that was expected, De said, because the surrounding gas is currently too dense to allow the radiation to escape into space.

Over time, as more material falls inward and the environment gradually clears, De expects telescopes may eventually detect X-rays "emerging from inside that mess that exists right now," potentially revealing the black hole more directly.

The findings also offer a new blueprint for discovering similar events, the researchers say. Instead of painstakingly monitoring billions of stars in nearby galaxies to see which ones suddenly vanish, astronomers can search for brief infrared flare-ups — possible warning signs that a star is about to undergo a quiet collapse like M31-2014-DS1.

"This is essentially as close as we can get to seeing the death of a massive star," said De. "In the end, I think it teaches us a lot more about stellar physics by not exploding."

A study about this star is reported in a paper published Thursday (Feb. 12) in journal Science.

A jet of charged particles moving at almost the speed of light, made from the remnants of a star that was brutally ripped apart by a supermassive black hole, has been found to be one of the most luminous, energetic events astronomers have ever witnessed in the universe.

The jet, triggered by what astronomers refer to as a tidal disruption event (TDE), is so powerful that finding an real world phenomenon to compare it to is difficult. And so, the astronomers led by Yvette Cendes of the University of Oregon have opted to compare it to the estimated energy output of a fictional device: Star Wars' Death Star, which can blow up entire planets.

The TDE and associated jet is unleashing between a trillion and 100 trillion times more energy than what fan estimates claim the Death Star produces. And, as in the case of the Death Star, any planets in the way of this jet are going to be in for a rough time.

"Planets are going to be destroyed for the first few light-years," Cendes, who is a radio astronomer, told Space.com. "I'm just not sure how far out from the jet this would be the case."

More specifically, the total energy of this event, which has been officially catalogued as AT2018hyz, depends upon how that energy is being emitted. Relativistic jets from TDEs are very rare, accounting for about 1% of all known cases. The other 99% are a spherical outflow that moves much more slowly. In the latter case we’d be looking at an energy output of 2 x 10^50 ergs (an erg is a unit of energy; the sun outputs 10^33 ergs at its peak) while the jet scenario, which Cendes favors given the immense luminosity of AT2018hyz, would reach 5 x 10^55 ergs.

And the energy output continues to increase. Models suggest that it will peak in 2027 before gradually climbing back down.

"I am hesitant to give a final energy estimate — there are too many things that it will depend on that will become clear once we actually see the peak," said Cendes. "But we anticipate that it will be about twice as luminous at the peak than what it is now."

So, how did this immense eruption of energy come about? AT2018hyz was initially detected in 2018 and at the time it seemed like a fairly ordinary TDE, of which just a little more than 100 have been seen.

"There was nothing from that initial discovery that made us think something like this was going to happen years later," said Cendes.

A TDE occurs when a star wanders a little too close to a supermassive black hole. In the case of AT2018hyz, the black hole resides in an otherwise fairly quiet galaxy 665 million light-years away.

Tidal forces, whereby one side of the star feels a greater gravitational pull from the black hole than the opposite side, begin to stretch and tear apart the star in a vice-like grip, effectively shredding it.

For a few years after its initial discovery, nothing much happened to AT2018hyz. Astronomers are not sure why, but there is often a wait period with TDEs. With that in mind, one hypothesis is that it takes a little time for the shredded stellar material to wrap around the black hole and form an accretion disk.

Some of the stellar material falls into the black hole, but much of it is directed away from the black hole by magnetic fields.

AT2018hyz was seen to come alive again in 2022, when it suddenly grew bright in radio waves probably produced by synchrotron radiation from the jet. This jet is so powerful that Cendes has even nicknamed it "Jetty McJetface" — in reference to the notorious Boaty McBoatface incident — and it is currently 50 times more luminous than upon its original detection. To see a black hole continue to emit so much energy so many years after consuming a star is considered unprecedented.

Another advantage of the jet explanation is that it would solve the mystery of why the energy output is still rising.

When such jets are first produced they are highly collimated with a narrow opening angle, and if the jet wasn't pointed directly at us, but was at an angle to us, then we wouldn't have seen its full blast. However, over time jets tend to broaden.

"And now it is entering our line of sight as the jet decelerates," says Cendes "As to how you get these relativistic jets from a TDE, well no one knows for sure but it's an active area of research. It probably has something to do with magnetic fields, but you clearly also need some other things to happen or we’d see them more commonly in TDEs."

Cendes now wants to hunt for more of these exceptionally energetic events. With the Square Kilometer Array (SKA) set to come online in the next decade, astronomers will finally have a tool that can survey the radio sky to great precision and sensitivity, potentially finding many more radio jets not just from TDEs, but also from galaxies that are more regularly active.

Cendes' team's findings were published on Feb. 5 in The Astrophysical Journal.

An incredibly energetic "impossible" particle that hit Earth in 2023 may have been debris from an exploding primordial black hole formed during the Big Bang. If that is the case, then it could prove the existence of primordial black holes, which could then help explain what the universe's most mysterious "stuff," dark matter, is made of.

The particle in question was a neutrino with an energy 100,000 times greater than that of the highest-energy particles produced by the world's largest and most powerful particle accelerator, the Large Hadron Collider (LHC). In fact, the particle was so energetic that scientists aren't aware of any natural cosmic phenomena powerful enough to create it.

Now, a team of researchers from the University of Massachusetts Amherst suggests that a particle like this could be blasted out when a so-called "quasi-extremal primordial black hole" explodes.

The key to black hole explosions is the leaking of Hawking radiation, a type of thermal radiation named for physicist Stephen Hawking, who first proposed its existence in 1974. The hotter a black hole is, the quicker it leaks Hawking radiation, losing mass and then finally ending its life in a massive explosion.

The catch is that the bigger a black hole is, the colder it is, and the more slowly it loses thermal radiation to its surroundings. Thus, even the smallest stellar mass black holes, born when massive stars go supernova at the end of their lives, would take about 10^67 years, vastly longer than the age of the universe, to leak enough radiation to reach this explosive stage.

However, Hawking also theorized that another type of black hole may exist, one born not from the death of a star but directly from density fluctuations in the "primordial sea" of ultrahot particles that filled the cosmos during its first moments after the Big Bang. And because these primordial black holes can be extremely small, with masses down to that of a planet or even a large asteroid rather than 3 to 5 times the mass of the sun, like the smallest stellar mass black holes, then they could be hot enough to leak Hawking radiation efficiently enough to explode.

"The lighter a black hole is, the hotter it should be and the more particles it will emit," team member Andrea Thamm of the University of Massachusetts Amherst said in a statement. "As primordial black holes evaporate, they become ever lighter, and so hotter, emitting even more radiation in a runaway process until explosion. It's that Hawking radiation that our telescopes can detect."

The astronomers behind this research estimate that a primordial black hole should explode with a frequency of around one every ten years or so. Thus far, none of these explosions have been detected, and therefore, primordial black holes and Hawking radiation both remain purely theoretical. That is, of course, unless evidence of an exploding primordial black hole was discovered courtesy of a different type of detection, the true nature of which wasn't immediately grasped.

The impossible particle

The impossibly energetic neutrino was detected in 2023 by a network of neutrino detectors called KM3NeT located in the Mediterranean Sea.

"Observing the high-energy neutrino was an incredible event," team member and University of Massachusetts Amherst researcher Michael Baker said. "It gave us a new window on the universe. But we could now be on the cusp of experimentally verifying Hawking radiation, obtaining evidence for both primordial black holes and new particles beyond the Standard Model, and explaining the mystery of dark matter."

However, there is a hitch. The event wasn't picked up by a similar neutrino detector called IceCube, situated deep within the ice of the South Pole. That was a problem, because IceCube was specifically designed to detect high-energy neutrinos, and yet it's never detected one of these particles with even 1/100 of the energy of the impossible neutrino.

If a primordial black hole explodes once a decade, then IceCube should be bombarded with high-energy neutrinos. So where are they?

The University of Massachusetts Amherst team has a theory.

"We think that primordial black holes with a 'dark charge' — what we call quasi-extremal primordial black holes — are the missing link," team member Joaquim Iguaz Juan of the University of Massachusetts Amherst said.

A "dark charge" is a version of the electromagnetic force that we are familiar with, but is carried not by a standard electron, but by a much heavier relative, a hypothetical particle called a "dark electron."

"There are other, simpler models of primordial black holes out there," Baker said. "Our dark-charge model is more complex, which means it may provide a more accurate model of reality. What's so cool is to see that our model can explain this otherwise unexplainable phenomenon."

A primordial black hole with a dark charge would have unique properties that make it behave differently from a standard primordial black hole, and that could not only explain the impossible neutrino but it could also solve the mystery of what dark matter actually is.

Dark matter has been so problematic because, unlike the particles that comprise standard matter, it doesn't interact with electromagnetic radiation, or "light." This means that despite outweighing ordinary particles by a ratio of 5 to 1, dark matter is effectively invisible and totally mysterious. One possible candidate for dark matter is primordial black holes.

"If our hypothesized dark charge is true, then we believe there could be a significant population of primordial black holes, which would be consistent with other astrophysical observations, and account for all the missing dark matter in the universe," Iguaz Juan concluded.

The team's research was accepted for publication in the journal Physical Review Letters.

Using the Event Horizon Telescope (EHT), astronomers have tracked a 3,000 light-years-long cosmic blowtorch back to its source, the supermassive black hole M87*, which bears the distinction of being the first black hole imaged by humanity. The breakthrough could help scientists better understand what creates these powerful jets of charged particles that travel at speeds approaching the speed of light.

M87* sits at the heart of the galaxy Messier 87 (M87), located around 55 million light-years from Earth. The historic image of this supermassive black hole, which has a mass equivalent to that of 6.5 billion suns, was captured by the EHT in 2017 and was released to the public in April 2019.

Not only is this supermassive black hole more massive than the one at the heart of the Milky Way, Sagittarius A* (Sgr A*), which has a mass around 4 million solar masses, but M87* is also an active black hole. That means it is greedily devouring its surrounding gas and dust as well as launching powerful jets from its poles. However, the exact source of these jets around their black hole central engines and the precise mechanism powering them is still something of a mystery.

To better understand the jet of this supermassive black hole, astronomers turned to the EHT's observations of M87* taken in 2021 using a technique called Very Long Baseline Interferometry (VLBI). This technique can reveal structures around supermassive black holes at small scales, such as the glowing golden ring of super-hot matter that dominates the 2019 image of M87*, which is effectively the "shadow" of this black hole. Using these newer observations, the team was finally able connect the glowing ring of material around M87* to the base of the jet erupting from this supermassive black hole, giving a probable origin point for this jet.

"This study represents an early step toward connecting theoretical ideas about jet launching with direct observations," team leader Saurabh of the Max Planck Institute for Radio Astronomy (MPIfR) said in a statement. "Identifying where the jet may originate and how it connects to the black hole's shadow adds a key piece to the puzzle and points toward a better understanding of how the central engine operates."

Performing modelling of the supermassive black hole, Saurabh discovered that radio emissions that were missing in EHT observations of M87* conducted between 2017 and 2019 but present in the 2021 observations were likely to originate from a compact region located less than a tenth of a light-year away from the black hole. This region is associated with the base of the M87* jet and corresponds with the southern arm of another jet seen in radio waves.

"We have observed the inner part of the jet of M87 with global VLBI experiments for many years, with ever-increasing resolution, and finally managed to resolve the black hole shadow in 2019," team member Hendrik Müller of the National Radio Astronomy Observatory (NRAO) said. "It is amazing to see that we are gradually moving towards combining these breakthrough observations across multiple frequencies and completing the picture of the jet launching region."

The team will now aim to make more observations of M87* to better understand the structure of its jet and to image the jet's fine details. This could lead to a better understanding of how supermassive black holes shape the environments around them.

The future is bright for black hole images.

The team's results were published on Wednesday (Jan. 28) in the journal Astronomy & Astrophysics.