128 Cosmic Mergers Detected by Gravitational Waves in a Single Campaign

A record harvest of cosmic mergers

128 new events in a few months

In March 2026, the international collaboration bringing together the LIGO, Virgo, and KAGRA observatories published its latest catalog of gravitational-wave events, an impressive list of 128 new cosmic mergers spotted between May 2023 and January 2024. This number, considerable by the standards of the field, reflects the spectacular progress made by these extremely precise instruments in recent years, capable of detecting minuscule ripples in spacetime coming from events at astronomical distances.

These gravitational waves, predicted at the start of the twentieth century by Albert Einstein as part of his theory of general relativity, correspond to tiny distortions in the very fabric of space and time, triggered by cosmic events of extreme violence. Their direct detection, first achieved in 2015, remains one of the greatest feats of contemporary experimental physics, and every new observing campaign considerably enriches our catalog of knowledge about these phenomena.

A growing variety of merging binary stars

This new catalog is not just a simple tally: it also reveals an ever greater variety of binary objects involved in these merger events. The 128 detected signals come from pairs of extremely dense objects, mainly black holes and neutron stars, whose orbits gradually tighten until they trigger a cataclysmic collision, releasing colossal energy in the form of gravitational ripples detectable from Earth.

This diversity of observed objects allows researchers to better map the different possible configurations of compact binary systems, whether two black holes merging together, two neutron stars, or mixed combinations pairing these two types of extreme objects, each producing a slightly different gravitational signature. This kind of diversity was simply out of reach back when the very first detections occurred, when only a handful of isolated signals hinted at the existence of these phenomena.

Some of the events recorded in this catalog even involve objects whose mass falls in an intermediate zone that remains poorly understood, neither quite that of a classic neutron star nor quite that of a lightweight black hole. These intriguing and rare cases are already fueling numerous theoretical debates about the exact nature of these objects and the astrophysical processes capable of producing them.

The trio of observatories behind this achievement

LIGO, Virgo, and KAGRA: worldwide cooperation

This scientific advance rests on close cooperation between three major international observatories: LIGO in the United States, Virgo in Europe, and KAGRA in Japan. Each of these instruments uses laser interferometry to detect extraordinarily tiny variations in distance, on the order of a fraction of a proton's diameter, caused by a gravitational wave passing through Earth.

Combining data from these three sites, geographically spread across several continents, not only confirms the reality of detected signals but also makes it possible to more precisely locate the source of these events in the sky, valuable information for then aiming optical and radio telescopes at the same region of the sky, in hopes of observing an electromagnetic counterpart to the event.

Instrument sensitivity constantly improving

The record number of detections announced in this 2026 catalog is largely explained by ongoing technical improvements made to the instruments since they first came online. Each new observing campaign benefits from upgrades that increase detector sensitivity, allowing them to pick up ever fainter signals coming from increasingly distant events in the observable universe, sometimes located several billion light-years from Earth.

This constant technical progress, documented on the official LIGO and Virgo websites, illustrates the cumulative nature of scientific progress in this field: every hardware improvement directly translates into a richer catalog of detections, paving the way for ever more robust statistical analyses of the population of compact objects in our universe. Engineers working on these instruments must constantly reduce sources of background noise, whether seismic vibrations, thermal fluctuations, or electronic interference, to allow the detectors to reach ever greater precision.

Each detector also relies on vacuum chambers stretching several kilometers, isolating the laser beams from the tiniest disturbances that could otherwise mask a genuine gravitational-wave signal. Maintaining this level of isolation requires constant monitoring, and every incremental gain in stability translates directly into the ability to catch weaker, more distant signals that would have gone unnoticed just a few years earlier.

What these detections reveal about black holes and neutron stars

Better understanding how binary systems form

Every newly detected merger gives astrophysicists valuable information about how compact binary systems form and evolve. By analyzing the precise characteristics of a signal, including the mass of the objects involved, their rotation speed, and the distance at which the event occurred, researchers can reconstruct the history of these pairs of stars, sometimes formed billions of years before their final merger.

This data also allows scientists to test different hypotheses about the stellar formation mechanisms that lead to the emergence of black holes and neutron stars, as well as the dynamic processes that gradually bring two such objects together until their final collision, a subject that remains actively debated within the international scientific community.

Ever more precise tests of general relativity

Beyond their interest for stellar astrophysics, these 128 new detections also offer an opportunity to subject Einstein's theory of general relativity to tests of unmatched precision. Every signal captured by the observatories is, in effect, a unique opportunity to verify whether theoretical predictions about the propagation of gravitational waves exactly match real observations, under extreme physical conditions impossible to reproduce in any laboratory on Earth.

So far, these repeated tests confirm with remarkable consistency the validity of Einstein's theory, more than a century after it was first formulated, further cementing this theory's reputation as one of the sturdiest pillars of modern physics. Some physicists nonetheless hope that the accumulation of data will eventually reveal subtle anomalies, potentially opening the door to a still more fundamental physics beyond general relativity, an ambitious goal that drives much of the current research in this field.

For now, no significant deviation has been found among the 128 new events in the catalog, which is itself a highly valuable piece of scientific information: it means Einstein's theory continues to describe, with remarkable precision, phenomena occurring under conditions of extreme gravity, precisely where many alternative theories predicted measurable discrepancies.

A database accessible to the entire scientific community

The central role of the public GWOSC archive

An essential part of this scientific approach lies in making the collected data publicly available, through platforms like GWOSC, the open archive of gravitational-wave observations. This accessibility allows researchers around the world, beyond the teams directly involved in the LIGO, Virgo, and KAGRA collaborations, to use this data for their own independent research work, a fundamental principle of modern scientific practice.

This open-access policy, widely praised by the international scientific community, helps speed up the pace of discovery by avoiding any withholding of valuable information, while also allowing independent verification of results announced by the teams that made the original observations.

A valuable resource for decades to come

This catalog of 128 events will add to an already substantial database, accumulated since the first historic detection in 2015. Every new addition helps refine the statistical models used to estimate the real frequency of these cosmic phenomena in the observable universe, as well as the mass distribution of the compact objects involved in these spectacular mergers.

This gradual accumulation of data represents a precious scientific legacy, one that will continue to be used by future generations of researchers, long after the end of the observing campaign that gathered these 128 new gravitational signals.

The future of gravitational-wave detection

Toward even greater detector sensitivity

The scientific teams responsible for LIGO, Virgo, and KAGRA are actively working to further improve the sensitivity of their respective instruments, ahead of future observing campaigns. These technical improvements, however subtle in daily operation, directly translate into a greater number and diversity of detectable events, considerably widening our observational window onto the most extreme phenomena in the universe.

This ongoing optimization work, carried out over several years by teams of engineers and physicists spread across three continents, shows just how much gravitational-wave detection remains a field in constant evolution, far from having reached its current technological limits. The next observing campaigns, already planned for the coming years, should benefit from these cumulative improvements to surpass the record of 128 detections set during this latest campaign.

New observatories on the horizon

Beyond upgrades to existing instruments, the international scientific community is also preparing to build new gravitational-wave observatories, which will complement the current network in the years ahead. These future instruments, even more sensitive, should make it possible to detect more distant and fainter events, pushing the frontiers of our knowledge of the gravitational universe ever further. Some projects even envision installing detectors in space, to completely escape the seismic disturbances on Earth that limit the sensitivity of ground-based instruments.

This ongoing expansion of the global detector network reflects the importance the international community places on this field of research, considered one of the most promising frontiers of contemporary astrophysics for decades to come. Proposed space-based detectors, still years away from launch, could eventually detect entirely different classes of gravitational-wave sources, including signals produced by the slow inspiral of supermassive black holes at the centers of merging galaxies.

Why this catalog fascinates astrophysicists so much

A unique window onto invisible phenomena

What makes these 128 new detections so fascinating is that they offer a unique window onto cosmic phenomena completely invisible to traditional optical observation. Unlike light, gravitational waves pass through matter without being absorbed or deflected, making it possible to directly observe events that would otherwise remain completely hidden from our conventional instruments, including the most powerful optical telescopes ever built.

This unique ability to probe otherwise inaccessible phenomena explains the constant enthusiasm this field of research generates within the scientific community, with every new observing campaign bringing its share of surprises and valuable theoretical confirmations for our overall understanding of the universe. It also explains why funding agencies across several continents keep investing in these observatories, even though a single upgrade cycle can take years to complete before yielding tangible scientific returns.

A young scientific field full of promise

Finally, it is worth remembering that the direct detection of gravitational waves remains a relatively young scientific field, since the very first observation only dates back to 2015. In just a decade, this discipline has produced considerable results, moving from a handful of historic detections to a catalog now counting several hundred confirmed events, including these 128 new mergers revealed in 2026.

This rapid progress points to a particularly rich future for gravitational-wave astrophysics, a field that will very likely continue delivering major surprises as instruments gain in sensitivity and the global catalog of detected events keeps growing year after year. For a discipline that did not even exist as an observational science before 2015, that trajectory is itself remarkable, and it suggests that the most significant discoveries in this area may still lie ahead rather than behind.

By Maxime Marquette, columnist

Sources

Primary sources

LIGO Caltech — Gravitational-wave observatory — 2026

Virgo — European gravitational-wave collaboration — 2026

GWOSC — Open archive of gravitational-wave observations — 2026

Secondary sources

CNRS — En direct des labos — 2026

Pour la Science — Quantum physics and gravitational waves — 2026

Futura Sciences — Sciences — 2026