Category: black holes

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.

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.

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.