This computer simulation shows the merger of 2 black holes. As the black holes spiral toward each other, collide and merge, they create gravitational waves. Scientists made this simulation using equations from Albert Einstein’s theory of general relativity and data from the Laser Interferometer Gravitational-wave Observatory (LIGO). Video via the Simulating eXtreme Spacetimes (SXS) project.
- Scientists detected 128 new gravitational waves signatures in 9 months, surpassing the previous total of 90.
- The new catalog includes the heaviest black hole binary merger ever found, with each object roughly 130 times the mass of our sun.
- Researchers are using gravitational wave data to test Einstein’s theory of general relativity and measure the universe’s expansion rate.
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128 new gravitational wave signatures
Black holes are the densest objects in the universe. When they collide, as they sometimes do, they unleash ripples in spacetime known to scientists as gravitational waves. These waves, traveling across millions to billions of light-years of space, are barely perceptible when they reach us here on Earth. But scientists have built incredibly sensitive instruments to detect their signatures.
On March 5, 2026, a team cataloging these violent mergers of black holes said they detected 128 new signatures over a 9-month period. It’s a significant increase over the 90 prior detections.
In addition, they’ve also found the heaviest binary black hole ever detected and the fastest spinning black holes.
Stephen Fairhurst, of Cardiff University, is a co-author of the new paper. He said:
In the past decade, gravitational wave astronomy has progressed from the first detection to the observation of hundreds of black hole mergers. 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.
The researchers published their findings in the peer-reviewed journal Astrophysical Journal Letters on December 9, 2025.
Gravitational waves are ripples in spacetime
When you throw a pebble into a pond, waves ripple out. Gravitational waves behave similarly. However, these ripples move at the speed of light, perturbing spacetime. That’s our four-dimensional realm where space and time are woven together.
Einstein’s theory of general relativity predicted the existence of gravitational waves. Then, in 1974, astronomers found the first indirect evidence of it in radio telescope observations of two pulsars orbiting each other. However, it wasn’t until 2015 that scientists first directly detected gravitational waves from two colliding black holes, 1.3 billion light-years away. Their data came from an observatory called LIGO, short for Laser Interferometer Gravitational-wave Observatory.
Three observatories reveal new violent cosmic events
Today, thanks to improved technology and data analysis techniques, LIGO and two other gravitational wave observatories are capturing more new events. LIGO has two facilities in the U.S., in Washington state and Louisiana. Meanwhile, two other observatories searching for gravitational waves are the Virgo interferometer in Italy and the Kamioka Gravitational Wave Detector (KAGRA) in Japan.
Scientists at these facilities collaborated to create the Gravitational-Wave Transient Catalog-4.0 (GWTC-4.0). It captured a list of events from May 2023 to January 2024. During that time, 128 new signals were detected. This is significant because the previous tally of events was just 90. Daniel Williams of the University of Glasgow commented:
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. We are really pushing the edges and are seeing things that are more massive, spinning faster and are more astrophysically interesting and unusual.
Strange phenomena in the universe
From the data, scientists are able to discern the type of objects creating the waves, their distance and even some characteristics. Also, if three or more observatories captured the same signal, they could determine its general location in the sky.
Researchers have found, in this new catalog, the heaviest black hole binary merger ever detected. Each black hole was about 130 times the mass of our sun. Plus, they think those black holes might have formed by the mergers of earlier, less massive black holes.
They also found an unusual black hole pair where each black hole was spinning exceptionally fast, at 40 times the speed of light. Here, the scientists also suspect these objects were created by smaller black holes.
In addition, the researchers uncovered an odd couple: one black hole was twice as massive as the other.
Jack Heinzel, of the Massachusetts Institute of Technology, said:
One of the striking things about our collection of black holes is their broad range of properties. Some of them are over 100 times the mass of our sun, others are as small as only a few times the mass of the sun. Some black holes are rapidly spinning, others have no measurable spin. We still don’t completely understand how black holes form in the universe, but our observations offer a crucial insight into these questions.
These new results open up questions about how black holes formed in the early universe. Salvatore Vitale, also of the Massachusetts Institute of Technology, commented:
For instance, 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.
Testing Einstein’s theory of relativity
Scientists are using gravitational wave signatures to test Einstein’s theory of general relativity. Aaron Zimmerman, of the University of Texas at Austin, said:
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. 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.
Measuring the Hubble Constant
In addition, astronomers are using gravitational wave data to independently derive a value for the Hubble Constant. This is a key value in determining the expansion rate of the universe. They’ve come up with a value of 76 kilometers per second per megaparsec.
Rachel Gray at the University of Glasgow said:
Merging black holes have a really unique property: We can tell how far away they are from Earth just from analyzing their signals. So, every merging black hole gives us a measurement of the Hubble Constant, and by combining all of the gravitational wave sources together, we can vastly improve how accurate this measurement is.
It’s still early days for this method, and we expect to significantly improve our precision as we detect more gravitational wave sources.
How LIGO, Virgo and KAGRA work
LIGO is a sophisticated interferometer, a device that merges two sources of light to create interference patterns. When you throw two stones in a pond, each stone generates a ripple. Eventually, the ripples intersect, creating a new pattern. That’s called interference, and light acts in a similar way.
A brief animation showing the basic operation of the LIGO interferometer. Video via @transforming_physics, reproduced from animation provided by LIGO.
A gravitational wave observatory has two perpendicular arms. At LIGO, they’re each 2.5 miles (4 km) long. A beam of laser light is split to shine down each arm. At the end of the arm, the light bounces back so the two beams intersect to form an interference pattern.
However, when gravitational waves pass through us, spacetime itself oscillates. As a result, each wave stretches one arm of the instrument and compresses the other. Consequently, the laser light in each arm moves through slightly different lengths, resulting in a different interference pattern that reveals a lot of information about the objects that created the gravitational waves.
The change in arm length due to a gravitational wave is minuscule, about 1/1000th the width of a proton. Therefore, engineers designed these observatories to filter out outside influences. In addition, scientists need data from other observatories to confirm gravitational wave signatures, to make sure what they saw is not spurious.
Bottom line: A new catalog of gravitational wave signatures reveals many more observations of mostly black hole mergers, including the most massive one known.
Source: GWTC-4.0: An Introduction to Version 4.0 of the Gravitational-Wave Transient Catalog
Via Massachusetts Institute of Technology
Read more: The universe is vibrating, mounting evidence shows