Latest news with #KAGRA
Yahoo
a day ago
- Science
- Yahoo
Scientists Found a Black Hole That Shouldn't Exist. Now Physics Has a Problem.
Here's what you'll learn when you read this story: Over the past decade, the LIGO-Virgo-KAGRA (LVK) network has detected hundreds of black hole mergers, but none quiet as large as GW231123. At 225 solar masses, the black hole resulting from the merger far exceeds previous record holder GW190521, which weighed in at 140 solar masses. This black holes involved in this merger were actually so large that they challenge some of our understanding of stellar evolution. The Laser Interferometer Gravitational-wave Observatory, or LIGO, made major headlines in 2015 when scientists confirmed the first ever detection of gravitational waves—ripples in spacetime caused by highly energetic deep space phenomena (think: black hole mergers, supernovae, and neutron star collisions). This particular detection originated from a black hole merger that created a new black hole 62 times the mass of our Sun. The LIGO-Virgo-KAGRA (LVK) network of gravitational wave detectors hasn't let off the gas in the decade since, and has made hundreds of confirmed gravitational-wave detections, including the first neutron star merger in 2017 and the largest black hole merger (clocking in at 140 solar masses) in 2021. Now, in a preprint uploaded to the arXiv server, LVK scientists have provided evidence that there's a new heavyweight champion—a merger that produced a new 255-solar-mass black hole. Designated GW231123 for the date it was discovered (November 23, 2023, during the fourth observing run of the LVK network), this black hole is actually too big, according to our current best understanding of physics. 'This is the most massive black hole binary we've observed through gravitational waves, and it presents a real challenge to our understanding of black hole formation,' Mark Hannam, a member of the LVK Collaboration from Cardiff University, said in a press statement. 'Black holes this massive are forbidden through standard stellar evolution models.' To form this black hole, the two black hole predecessors likely had to measure around 100 and 140 times the mass of the Sun, respectively. This means they potentially lie in what's known as the 'upper-mass gap'—a range of masses in which black holes aren't thought to form from stars directly (the resulting supernovae of these hugely massive stars should leave behind no stellar remnant at all). 'One possibility is that the two black holes in this binary formed through earlier mergers of smaller black holes." Hannam said. However, these black holes' masses aren't the only mystery, as both were spinning between 80 and 90 percent of their top speed limit. This makes them the highest spinning black holes ever recorded by LVK. 'The black holes appear to be spinning very rapidly—near the limit allowed by Einstein's theory of general relativity,' Charlie Hoy, another member of the LVK from the University of Portsmouth, said in a press statement. 'That makes the signal difficult to model and interpret. It's an excellent case study for pushing forward the development of our theoretical tools.' Because the detectors are sensitive to black holes of around 100 solar masses, detecting one more than double that size certainly pushes LIGO to its limits. According to Science News, the LVK network was only able to detect the smallest blip from this merger, with only around 0.1 seconds detected at the tail end of the collision. LIGO's decades-long mission to detect gravitational waves has given scientists a whole new understanding of the universe, and nearly a decade after its first detection, it shows no signs of stopping. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life? Solve the daily Crossword
The Hindu
5 days ago
- Science
- The Hindu
New gravitational waves reveal black hole with ‘forbidden' mass
Scientists working with a network of observatories located around the world recently reported that they had detected a powerful and unusual burst of gravitational waves, which they called GW231123. The signal was traced back to two black holes colliding into each other on November 23, 2023. This isn't the first time the observatories have detected gravitational waves, but the event is special because of the extraordinary size of the black holes involved: they are much heavier than most seen before. More interesting is the fact that the heavier black hole appeared to have a 'forbidden' mass — a value inside a range called the pair instability mass gap — which challenges what physicists thought was possible for black holes created from dying stars. Imagine a massive star at the end of its life. Usually, very heavy stars explode in supernovae, leaving behind black holes. But theory predicts that no black holes should form with masses between about 60 and 130 times the mass of our sun. This is the pair instability mass gap: it's thought to exist because stars this large explode so violently that nothing remains, not even a black hole, just scattered gas. Above 130 solar masses, stars may skip the explosion and directly collapse to create supermassive black holes. So finding black holes in the mass gap raises important questions about how they got there. On November 23, 2023, the two Laser Interferometer Gravitational-wave Observatories (LIGO) in the U.S. detected a burst of gravitational waves, faint ripples in spacetime created by massive objects accelerating and colliding. The GW231123 event lasted only about one-tenth of a second and the signal was strong and clear. The collision happened about 2 billion lightyears away. Scientists at the LIGO as well as Virgo and KAGRA observatories in Italy and Japan, respectively, conducted a detailed analysis and determined the pre-merger mass of the two colliding black holes. The heavier one had 120-159 solar masses but likely centred at 137 solar masses. The lighter one weighed 51-123 solar masses but likely centred at 103 solar masses. The total mass involved in the collision was thus likely 190-265 solar masses, rendering GW231123 the most massive black hole merger ever seen with high confidence. The mass of the heavier black hole in the merger is right inside, or just above, the pair instability mass gap. The mass of the lighter one could also be in or near the gap, given the large uncertainty. According to theory, stars can't leave behind black holes in this range, so the scientists figure something else must be going on. They are already considering several explanations. One, for example, is called a hierarchical merger: smaller black holes could merge inside dense star clusters, then the resulting larger black holes merge again, building up over time and ending up inside the gap. This possibility finds some support from the fact that both black holes were spinning rapidly. Usually, black holes formed from individual stars aren't spinning this fast. Another possibility is a stellar merger. Sometimes, two stars might merge before they die, creating a much larger star that might collapse to form a black hole whose mass lands inside the gap. It's also possible these two black holes formed right after the Big Bang, by a process unrelated to stars, although this idea is in the realm of speculation. Yet other potential explanations include some stars losing less mass before exploding or hitherto entirely unknown processes. The main idea is that the detection of GW231123 suggests the universe can make black holes in the mass gap after all, and not just through the collapse of single stars. And that this fact means scientists' theories about the lives and deaths of massive stars need updating.
Time of India
5 days ago
- Science
- Time of India
Scientists discover the most massive crash of two black holes, each bigger than 100 Suns
The outer space has been home to mysterious, invisible giants with the power to bend space and time called Black holes. But recently, astronomers detected something so unique that it's forcing experts to rethink what we know about how black holes form and evolve. The discovery includes two black holes, whose size is more massive than 100 suns, crashing into one another in a collision that sent ripples through the fabric of space-time. In fact, the mass and spin of the black holes don't match what current models predict. This has given rise to new questions and possibilities about the life and growth of these cosmic powerhouses. The largest recorded black hole merger is a massive event named GW231123. Detected by the LIGO observatories in the US, along with partner detectors Virgo in Italy and KAGRA in Japan, this event involved two massive black holes, weighing roughly 100 and 140 times the mass of the sun. When they collided, they sent faint ripples through space-time called gravitational waves , a phenomenon first predicted by Einstein in 1915. 'These amazing detectors are really the most sensitive measuring instruments that human beings have ever built,' said Mark Hannam, head of the Gravity Exploration Institute at Cardiff University and a member of the LIGO Scientific Collaboration. 'We're observing the most violent and extreme events in the universe through the smallest measurements we can make.' Something that sets this event apart is the size and speed of the black holes involved. by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Die intelligentere Art, Ihre Anlageziele zu erreichen eToro Learn More Undo 'The individual black holes are special because they lie in a range of masses where we do not expect them to be produced from dying stars,' said Charlie Hoy, research fellow at the University of Plymouth and also part of the LIGO collaboration. This unusual mass range is known as the 'mass gap', meaning a theoretical range between about 60 and 130 solar masses where traditional star death isn't expected to create black holes. According to Hannam, 'There's a range of masses where we think that it's not possible for black holes to form that way. And the black holes from GW231123 live bang in the middle of that gap.' To explain this, researchers believe these black holes may be the result of earlier black hole mergers, which could essentially be a cosmic chain reaction. 'You can have this process where you just build up more and more massive black holes,' Hannam explained. Supporting this theory is the fact that the black holes appeared to be spinning near their physical limits. 'So far, most black holes we have found with gravitational waves have been spinning fairly slowly,' Hoy noted. 'This suggests that GW231123 may have formed through a different mechanism… or it could be a sign that our models need to change.' 'This new merger is very hard to explain in other ways,' said Zoltan Haiman, professor at the Institute of Science and Technology Austria, suggesting that these may be remnants of multiple generations of black hole mergers. Going ahead, future detections could reveal whether this record-breaking collision was a rare one-off or a clue to a much larger population of heavyweight black holes hiding in the universe.
Yahoo
6 days ago
- Science
- Yahoo
Astronomers detect most massive black hole collision to date
Sign up for CNN's Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. A collision observed between two black holes, each more massive than a hundred suns, is the largest merger of its kind ever recorded, according to new research. A team of astronomers discovered the event, dubbed GW231123, when the Laser Interferometer Gravitational-Wave Observatory (LIGO) — a pair of identical instruments located in Livingston, Louisiana, and Hanford, Washington — detected faint ripples in space-time produced by two black holes slamming into each other. Physicists call such ripples gravitational waves. Gravitational waves were predicted by Albert Einstein in 1915 as part of his theory of relativity, but he thought they were too weak to ever be discovered by human technology. In 2016, however, LIGO detected them for the very first time when black holes collided, proving Einstein right (once again). The following year, three scientists received awards for their key contributions to the development of what has been colloquially called a 'black hole telescope.' Since the first detection of gravitational waves, LIGO and its sister instruments — Virgo in Italy, and KAGRA in Japan — have picked up signs of about 300 black hole mergers. 'These amazing detectors are really the most sensitive measuring instruments that human beings have ever built,' said Mark Hannam, head of Gravity Exploration Institute at Cardiff University in the UK and a member of the LIGO Scientific Collaboration. 'So, we're observing the most violent and extreme events in the universe through the smallest measurements we can make.' GW231123, however, is exceptional among those 300 black hole mergers, and not just because it is the most massive of the collisions. 'The individual black holes are special because they lie in a range of masses where we do not expect them to be produced from dying stars,' said Charlie Hoy, a research fellow at the University of Plymouth in the UK who's also a member of the LIGO Scientific Collaboration. 'As if this wasn't enough,' he continued, 'the black holes are also likely spinning almost as fast as physically possible. GW231123 presents a real challenge to our understanding of black hole formation.' A 'mass gap' Gravitational waves are the only way scientists can observe a collision in a binary system in which two black holes orbit each other. 'Before we could observe them with gravitational waves, there was even a question of whether black hole binaries even existed,' Hannam said. 'Black holes don't give off any light or any other electromagnetic radiation, so any kind of regular telescope is unable to observe them.' According to Einstein's theory of general relativity, gravity is a stretching of space and time, and it forces objects to move through curved space. When objects move very rapidly, like spinning black holes, the curved space forms ripples that spread outward like waves. These gravitational waves are 'ridiculously weak,' according to Hannam, and there are limitations to the information they can provide. For example, there's uncertainty about the distance of GW231123 from Earth; it could be up to 12 billion light-years away. Hannam is more confident about the mass of the two black holes, which are believed to be approximately 100 and 140 times the mass of the sun. Those numbers, however, are puzzling: 'There are standard mechanisms where black holes form — when stars run out of fuel and die and then collapse,' Hannam said. 'But there's a range of masses where we think that it's not possible for black holes to form that way. And the black holes from GW231123 live bang in the middle of that (mass) gap. So there's a question of how they formed and that makes them pretty interesting.' The 'mass gap' Hannam refers to starts at about 60 solar masses and goes up to roughly 130, but because it is a theoretical range, meaning it has not been directly observed, there is some uncertainty about where this gap starts and where it ends. But if the black holes from GW231123 indeed fall into this gap, then they likely didn't form from stars collapsing, but in some other way. In a study published Monday on the open access repository Arxiv, Hannam and his colleagues suggest that the 'mass gap' could be explained if the two black holes are the results of previous mergers, rather than the product of dying stars. 'This is a mechanism that people have talked about in the past and we've seen hints of before,' he said. In this scenario, a chain reaction of black hole mergers occurs. 'You can have this process where you just build up more and more massive black holes. And since the black holes in GW231123 look like they're at masses where you couldn't get them by normal mechanisms, this is a strong hint that this other process is going on where you have these successive mergers,' Hannam explained. If this hypothesis were to be confirmed, it would suggest the existence of an unexpected population of black holes that, in terms of mass, fall somewhere between black holes that form from the death of massive stars and the supermassive black holes that are found in the centers of galaxies, said Dan Wilkins, a research scientist at the Kavli Institute for Particle Astrophysics and Cosmology of Stanford University. Wilkins was not involved with the GW231123 discovery. 'Gravitational waves are opening a really interesting window into black holes, and are revealing some really intriguing mysteries,' he added. 'Before the advent of gravitational wave astronomy, we could only detect black holes that are actively growing by pulling in material, producing a powerful light source. Gravitational waves are showing us a different part of the black hole population that is growing not by pulling in material, but instead by merging with other black holes.' Spinning very fast The other surprising feature of GW231123 is how quickly the two black holes are spinning around each other. 'So far, most black holes we have found with gravitational waves have been spinning fairly slowly,' said Charlie Hoy. 'This suggests that GW231123 may have formed through a different mechanism compared to other observed mergers, or it could be a sign that our models need to change.' Such high-speed spins are hard to produce, but they also support the idea that the black holes had undergone prior mergers, because scientists would expect previously merged black holes to spin faster, according to Hannam. 'GW231123 challenges our models of gravitational wave signals, as it is complex to model such (fast) spins, and it stands out as an extraordinary event that is puzzling to interpret,' said Sophie Bini, a postdoctoral researcher at Caltech and a member of the LIGO-Virgo-KAGRA Collaboration. 'What surprised me the most is how much there is still to learn about gravitational waves. I really hope that in the future we can observe other events similar to GW231123 to improve our understanding of such systems.' The previous record for the most massive black hole merger ever observed belonged to a merger called GW190521, which was only 60% as big as GW231123. But scientists could find even more massive mergers in the future, Hannam said, and the collisions might one day be observed through even more accurate instruments that could become available the next couple of decades, such as the proposed Cosmic Explorer in the US and the Einstein Telescope in Europe. This new discovery opens a new window on how black holes can form and grow, said Imre Bartos, an associate professor at the University of Florida who was not involved with the research. 'It also shows how quickly gravitational wave astronomy is maturing,' he added. 'In less than a decade we've moved from first detection to charting territory that challenges our best theories.' While he agrees that previous mergers could explain both the high mass and the fast spin of the black holes, other possibilities include repeated collisions in young star clusters or the direct collapse of an unusually massive star. He added, however, that those possibilities would be less likely to produce black holes that spin this fast. It is very natural to explain the black holes in GW231123 as remnants of one or even multiple generations of previous mergers, said Zoltan Haiman, a professor at the Institute of Science and Technology Austria who also was not involved with the discovery. 'This idea was already raised immediately after the first ever LIGO detection of a (black hole) merger, but this new merger is very hard to explain in other ways.' Future detections, he added, will tell us 'whether this heavyweight bout was a one‑off or the tip of a very hefty iceberg.' Solve the daily Crossword
The Hindu
15-07-2025
- Science
- The Hindu
What is a black hole merger?
A: A black hole merger happens when two black holes — extremely dense objects with gravity so strong that not even light can escape — get close and start orbiting each other. Over time, they lose energy by sending out invisible ripples in spacetime called gravitational waves. As they spiral closer together, their orbit shrinks until they finally crash and combine into a single, bigger black hole. This moment releases a huge burst of gravitational waves, which can be detected on the earth by special observatories like LIGO in the US, Virgo in Italy, and KAGRA in Japan. Think of the phenomenon like two figure skaters spinning toward each other and then grabbing hands to spin faster as one, except in extreme physical conditions. Catching these events allows scientists to learn new things about black holes and the universe. In fact, on July 10, an international collaboration of scientists reported discovering an especially massive black hole merger, named GW231123. LIGO, Virgo, and KAGRA had detected gravitational waves from the merger on November 23, 2023. In this event, two black holes, about 137x and 103x the mass of the sun, crashed together, forming an even bigger black hole. This was unusual because black holes in this mass range are thought to be rare. The discovery suggests large black holes might form when smaller ones merge, not just from dying stars. GW231123 also showed both original black holes spinning really fast, which challenges existing theories of their existence.
