Astronomers have unveiled the largest collection yet of gravitational wave detections, marking a major leap forward in our understanding of black holes and the universe itself.
The new catalog, called GWTC-5, contains 161 newly confirmed signals from colliding black holes detected between April 2024 and January 2025.
These discoveries were made by the international LVK collaboration, which operates the powerful gravitational wave observatories LIGO in the United States, Virgo in Italy, and KAGRA in Japan.
With these additions, the total number of gravitational wave signals ever detected has now reached 390.
Gravitational waves are tiny ripples in space-time created by violent cosmic events, such as black holes crashing into each other.
These ripples are incredibly difficult to detect because they distort space by amounts smaller than the width of an atom. Scientists rely on ultra-sensitive instruments to measure them.
Researchers at the University of Glasgow have been involved in gravitational wave research for decades.
They helped develop key technology used inside the LIGO detectors, including the delicate mirror suspension systems that allow the observatories to sense these tiny distortions.
Since the first historic detection of gravitational waves in 2015, the number of discoveries has grown rapidly as the detectors become more sensitive. Scientists are now detecting around three or four signals every week.
The new catalog contains several record-breaking discoveries. One signal, known as GW240615, produced the most accurate sky location ever achieved for a gravitational wave source. Scientists narrowed its origin down to an area of only six square degrees in the sky, which is remarkably precise for this type of observation.
That event came from two black holes, about 26 and 30 times the mass of the sun, merging more than 3 billion light-years away from Earth.
The updated catalog is also helping researchers tackle one of the biggest mysteries in cosmology: how fast the universe is expanding. This expansion rate is described by the Hubble constant.
Gravitational waves provide a new way to measure cosmic distances. By estimating how far away black hole mergers occur, and sometimes identifying the galaxies where they happened, scientists can improve calculations of the universe’s expansion.
The return of the Virgo detector during this observing period greatly improved scientists’ ability to pinpoint where signals came from. Researchers also used 236 gravitational wave events for their analysis, nearly double the number used in previous studies.
Another standout event, called GW250114, became the clearest gravitational wave signal ever recorded. It had an exceptionally high signal-to-noise ratio, meaning the signal stood out sharply from background noise.
The event was caused by two nearly equal-sized black holes, weighing about 32 and 34 solar masses, merging more than a billion light-years away.
Because the signal was so clear, scientists were able to perform one of the best tests yet of Albert Einstein’s general theory of relativity. The data also supported physicist Stephen Hawking’s black hole area theorem, which predicts that the total surface area of black holes should increase after a merger.
Researchers also found growing evidence for the existence of “second-generation” black holes. These are black holes formed not directly from collapsing stars, but from earlier black hole mergers.
Two events detected in late 2024 showed strong signs of this process. Scientists believe these repeated mergers likely happen inside crowded regions such as dense star clusters, where black holes frequently interact and collide.
By studying hundreds of events together, scientists are beginning to see patterns in black hole masses, spins, and formation histories. Researchers say the growing catalog is no longer just revealing isolated cosmic accidents — it is starting to uncover the hidden structure of an entire population of black holes across the universe.
Source: University of Glasgow.
