Space & Physics
The Universe Is Ringing
How gravitational waves from colliding black holes are opening an entirely new way of exploring the cosmos
More than a century after Albert Einstein predicted them, gravitational waves are transforming astronomy. Ripples in space-time produced by colliding black holes and neutron stars are now being detected routinely, revealing a universe filled with violent mergers and cosmic echoes that have travelled billions of years to reach Earth.
A Ripple Across the Cosmos
When the densest objects in the universe collide, the impact does not simply end with the destruction or merger of stars. It sends ripples through the very fabric of space and time.
These ripples—known as gravitational waves—spread outward at the speed of light, crossing galaxies and cosmic voids for millions or even billions of years. By the time they reach Earth, they are unimaginably faint distortions of space itself.
Yet scientists have learned how to detect them.

A global network of observatories now monitors these tiny disturbances: the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United States, the Virgo detector in Italy, and the Kamioka Gravitational Wave Detector (KAGRA) in Japan. Together, these instruments form one of the most sensitive scientific experiments ever constructed, capable of detecting distortions smaller than the width of a proton.
Through them, astronomers have begun to “listen” to the universe.
And what they are hearing is astonishing.
A Universe Filled with Collisions
The LIGO–Virgo–KAGRA (LVK) Collaboration has now released the latest compilation of gravitational-wave detections, to appear in a special issue of Astrophysical Journal Letters. The findings suggest that the cosmos is reverberating with collisions far more frequently than scientists once imagined.
The newly released Gravitational-Wave Transient Catalog-4.0 (GWTC-4) includes detections from part of the observatories’ fourth observing run, conducted between May 2023 and January 2024.

In just nine months, the detectors recorded 128 new gravitational-wave candidates—signals that likely originated from extreme astrophysical events occurring hundreds of millions or billions of light-years away.
This newest batch more than doubles the size of the gravitational-wave catalog, which previously contained 90 candidates from earlier observing runs.
“The beautiful science that we are able to do with this catalog is enabled by significant improvements in the sensitivity of the gravitational-wave detectors as well as more powerful analysis techniques,” says Nergis Mavalvala, a member of the LVK collaboration and dean of the MIT School of Science.

What began in 2015 with the first historic detection has now become a steady stream of discoveries.
“In the past decade, gravitational wave astronomy has progressed from the first detection to the observation of hundreds of black hole mergers,” says Stephen Fairhurst, professor at Cardiff University and spokesperson for the LIGO Scientific Collaboration. “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.”
When Black Holes Dance
Most gravitational waves detected so far originate from binary black holes—pairs of black holes locked in orbit around each other.
Over time, gravity draws them closer together. As they spiral inward, they release enormous amounts of energy in the form of gravitational waves. In the final fraction of a second, the two objects merge in a titanic collision, forming a single, larger black hole.
These cosmic dances are among the most energetic events in the universe.

Black holes themselves are born when massive stars collapse at the end of their lives, compressing enormous amounts of matter into regions so dense that not even light can escape.
Many form in pairs. When they eventually collide, the event sends gravitational waves surging through space.
The first such detection, announced in 2016, confirmed a century-old prediction of Einstein’s theory of general relativity. Since then, dozens—and now hundreds—of similar events have been observed.
But the latest catalog shows that the universe is far more diverse than scientists once believed.

Pushing the Edges of Black Hole Physics
The newly detected signals reveal a remarkable variety of cosmic systems.
Among them are the heaviest black hole binaries ever detected, systems where the masses of the two black holes are strikingly unequal, and pairs spinning at astonishing speeds.
“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,” says Daniel Williams, a research fellow at the University of Glasgow. “We are really pushing the edges, and are seeing things that are more massive, spinning faster, and are more astrophysically interesting and unusual.”

One particularly dramatic signal—GW231123_135430—appears to have originated from two enormous black holes, each roughly 130 times the mass of the Sun. Most previously observed mergers involved black holes closer to 30 solar masses.
The extraordinary size of these objects suggests they may themselves have formed from earlier black hole mergers—a kind of cosmic generational chain.
Another remarkable event, GW231028_153006, revealed a binary in which both black holes are spinning at around 40 percent of the speed of light.
And in GW231118_005626, scientists detected an unusually uneven pair where one black hole is roughly twice as massive as the other.
“One of the striking things about our collection of black holes is their broad range of properties,” says Jack Heinzel, an MIT graduate student who contributed to the catalog’s analysis. “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,” he adds, “but our observations offer a crucial insight into these questions.”

Catching a Whisper in Space-Time
Detecting gravitational waves requires extraordinary precision.
The observatories use L-shaped interferometers with arms several kilometers long. Laser beams travel down these tunnels and reflect back to their source.
If a gravitational wave passes through the detector, it slightly stretches one arm while compressing the other, changing the distance the light travels by an incredibly tiny amount.
These changes can be smaller than one-thousandth the diameter of a proton.
Even with such advanced technology, detections remain unpredictable.

“You can’t ever predict when a gravitational wave is going to come into your detector,” says Amanda Baylor, a graduate student at the University of Wisconsin–Milwaukee who worked on the signal search. “We could have five detections in one day, or one detection every 20 days. The universe is just so random.”
Recent upgrades have dramatically improved the detectors’ reach. LIGO can now detect signals from neutron star collisions up to one billion light-years away, and black hole mergers far beyond that.
Testing Einstein’s Ultimate Theory
Gravitational waves are not only revealing spectacular cosmic events. They are also providing some of the most extreme tests ever conducted of Einstein’s theory of general relativity.
Black holes themselves are one of the most extraordinary predictions of the theory.
“Black holes are one of the most iconic and mind-bending predictions of general relativity,” says Aaron Zimmerman, associate professor of physics at the University of Texas at Austin.
When two black holes collide, he explains, they “shake up space and time more intensely than almost any other process we can imagine observing.”
One particularly powerful signal—GW230814_230901—allowed scientists to analyze the structure of the gravitational wave in exceptional detail.
“So far, the theory is passing all our tests,” Zimmerman says. “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 Expansion of the Universe
Gravitational waves are also becoming powerful tools for answering one of cosmology’s biggest questions: how fast the universe is expanding.
Astronomers measure this expansion using the Hubble constant, but different methods have produced conflicting results.
Gravitational waves offer an independent approach.
“Merging black holes have a really unique property: We can tell how far away they are from Earth just from analyzing their signals,” says Rachel Gray, a lecturer at the University of Glasgow.
“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.”
Using the current gravitational-wave catalog, scientists estimate that the universe is expanding at roughly 76 kilometers per second per megaparsec.
For now, the uncertainty remains large—but future detections could sharpen the measurement significantly.

Listening to the Future
Only a decade ago, gravitational waves were purely theoretical signals.
Today, they are transforming astronomy.
With every new detection, scientists gain another glimpse into the hidden life of the universe: the birth of black holes, the evolution of galaxies, and the behavior of gravity under the most extreme conditions imaginable.
“Each new gravitational-wave detection allows us to unlock another piece of the universe’s puzzle in ways we couldn’t just a decade ago,” says Lucy Thomas, a postdoctoral researcher at the Caltech LIGO Lab.
“It’s incredibly exciting to think about what astrophysical mysteries and surprises we can uncover with future observing runs.”
The instruments on Earth are quiet, their lasers moving silently down vacuum tunnels. But far beyond our galaxy, black holes continue to collide.
And with each collision, the universe sends out another ripple—another echo across the cosmos—waiting for us to hear it.
Space & Physics
Meteorite Dust Reveals Evidence of Magnetic Field in the Young Solar System
A magnetic field in the early solar system has been detected in ancient meteorite grains, offering evidence that magnetism helped shape the young sun.
Ancient grains in an Antarctic meteorite reveal evidence of a magnetic field in early solar system, suggesting magnetism helped shape the young sun
Tiny mineral grains preserved inside an ancient meteorite have recorded evidence of a magnetic field that existed during the earliest stages of the solar system, suggesting that magnetism, alongside gravity, helped shape the young sun and its surrounding disk of gas and dust.
Ancient Meteorite Records Reveal a Magnetic Field in the Early Solar System
Scientists at the Massachusetts Institute of Technology (MIT) examined microscopic grains in a meteorite recovered from Antarctica and found traces of ancient magnetism dating to the first 200,000 years of solar system history. The findings provide what researchers describe as the earliest known evidence of a magnetic field in the infant solar system.
The study, published in the Proceedings of the National Academy of Sciences, challenges the view that gravity alone drove the transformation of the early solar system from a cloud of gas and dust into a flattened disk that eventually produced the sun and planets.
“This transition, from a spherical cloud to a protoplanetary disk, is one of the most significant events in all of solar system history,” said Benjamin Weiss, professor of Earth and Planetary Sciences at MIT, in a statement issued. Measurements from the study, he said, indicate that magnetism likely played a role.
Magnetic records preserved in meteorite grains
The researchers studied DOM 08006, a primitive meteorite discovered in 2008 in the Dominion Range of Antarctica. The meteorite contains calcium-aluminum-rich inclusions, or CAIs, which formed during the earliest period of solar system development.
CAIs are among the oldest known solid materials from the solar system. Some of the grains contain magnetic minerals that can preserve the imprint of a magnetic field present when they formed.
The team isolated tiny grains from the meteorite and subjected them to a series of tests to determine whether they retained remanent magnetisation — a lasting record of an earlier magnetic field.
The researchers found evidence of a magnetic field with an estimated strength of about 150 to 600 microteslas. That is roughly three to 12 times stronger than Earth’s magnetic field today.
The preservation of these records was possible because DOM 08006 appears to have undergone relatively little alteration during its long history.
“Other meteorites went through many different processes over this 4.5 billion year history,” Weiss said. “But somehow, DOM has experienced less alteration than any other meteorite.”
Magnetism before the planets
Scientists already had evidence of magnetic fields in the solar system several million years after its formation, when the sun had formed and the planets were beginning to take shape.
The new measurements push that evidence much further back — to a period when the solar system was still a collapsing cloud of gas and dust and the sun itself was beginning to form.
In the early solar system, electrically charged particles moving through the developing disk could have generated a magnetic field. That field may then have influenced the movement of gas and material towards the central star.
The researchers argue that magnetism therefore needs to be considered alongside gravity when reconstructing how the early solar system evolved.
“We think these kinds of magnetic fields were helping to move gas from the protoplanetary disk, in toward this central star, the sun,” said Cauê Borlina, the study’s first author and now an assistant professor at Purdue University.
The findings do not replace gravity as the main force shaping the early solar system. Instead, they suggest that magnetic fields were another important part of the physical processes that brought material together and helped the young sun grow.
The study was led by Borlina, with Weiss, Elias Mansbach and Nilanjan Chatterjee of MIT, along with researchers from Tsinghua University, the University of Cambridge, Caltech and the University of California, Los Angeles
Space & Physics
NASA Puts $500,000 Prize on Better Satellite Tracking
NASA is offering up to 500,000 dollars to develop affordable technology that can improve satellite tracking by measuring atmospheric drag in low Earth orbit. The effort aims to help operators predict orbital changes more accurately as solar activity alters the thin upper atmosphere.
A faint layer of air high above Earth is becoming an important concern for satellite tracking operators. NASA is now offering up to USD 500,000 to individual winning teams that can develop a practical way to monitor it. The US space agency opened the Orbital Clarity Challenge on August 19, asking researchers and companies to develop instruments that can determine how much drag spacecraft experience in low Earth orbit. Up to four teams can win the top prize, taking the potential total award to USD 2 million.
The focus is the thermosphere, a region that begins about 80 kilometres above Earth and extends hundreds of kilometres into space. The air here is extremely sparse, but spacecraft moving through it still encounter enough resistance to gradually alter their orbits.

That resistance does not remain constant. When the Sun becomes more active, bursts of energy can heat the upper atmosphere. The thermosphere expands, increasing the amount of gas encountered by satellites. The resulting increase in drag can change their altitude and make their future position harder to calculate. For spacecraft operators, even a small difference can matter when several objects are moving through the same orbital region.
A Gap in the Data
NASA already relies on computer models to estimate atmospheric drag. But those calculations depend on how well scientists understand conditions in the upper atmosphere at a particular time and location. The agency wants new technology that can provide more direct information.
Under the competition, proposed instruments should be inexpensive enough to be deployed widely. NASA says they could potentially be carried aboard commercial spacecraft as hosted payloads, allowing measurements to be collected from several points in orbit rather than from a limited number of dedicated missions.
The competition will run through several stages, with NASA aiming to move successful ideas from an initial concept towards an instrument that can eventually be tested in space. Winning teams are also expected to receive an opportunity for an orbital demonstration. Applications for the first stage close in November 2026.
Satellite Tracking: Why this Matters?
The number of spacecraft operating in low Earth orbit has grown rapidly, with satellites supporting communications, navigation, Earth observation and scientific research.
Their paths are affected by several forces, including the thin atmosphere at orbital altitude. During periods of strong solar activity, atmospheric drag can rise sharply and contribute to changes in orbital altitude. Better information about those changes could help operators plan manoeuvres more accurately and improve forecasts of when satellites will descend from orbit.
NASA’s prize is therefore aimed at a relatively small piece of the space infrastructure puzzle: getting a clearer picture of the air that satellites are still moving through, even hundreds of kilometres above the ground.
Space & Physics
Sophie Adenot Makes History as First Frenchwoman to Walk in Space
French astronaut Sophie Adenot has become the first Frenchwoman to perform a spacewalk, spending 6 hours 23 minutes outside the International Space Station.
French astronaut Sophie Adenot has become the first Frenchwoman to perform a spacewalk, spending 6 hours and 23 minutes outside the International Space Station to begin repairs to its exterior communications system.
French astronaut Sophie Adenot made European space history on Tuesday by becoming the first French woman to perform a spacewalk outside the International Space Station. Adenot, 44, stepped outside the orbiting laboratory alongside American astronaut Anil Menon, floating roughly 400 kilometres above the Earth for 6 hours and 23 minutes to begin a repair of the station’s exterior communications equipment.
“I’m out,” Adenot said as she exited the station. “I feel very good now.”
A Repair Job That Ran Long The astronauts’ task was to replace an aging space-to-ground antenna on the station’s Z1 truss — the primary link carrying high-speed data, voice calls and video between the station and mission control in Houston. The antenna had stopped tracking NASA’s data relay satellites since November and had been out of service since, with a second antenna carrying the station’s communications load in the meantime.
Menon and Adenot successfully removed the failed antenna and secured it to the truss structure, but disconnecting its electrical cables and loosening its mounting bolts took longer than planned, leaving no time to install the replacement unit. NASA has scheduled a second spacewalk for Tuesday, August 25, to complete the installation. The station’s communications were not affected by the delay, as the backup antenna continued operating throughout.
Inside the station, astronauts Jack Hathaway and Jessica Meir coordinated the operation from the control desk, operating the station’s robotic arm and monitoring the spacewalkers’ life support systems throughout.
Days of Preparation Before the Hatch Opened Spacewalks demand days of preparation before the airlock ever opens. In the lead-up, Adenot and Menon spent dozens of hours readying their gear inside the station — inspecting safety tethers, organising tools, servicing backup emergency jetpacks, charging suit batteries, checking for pressure leaks, and testing biomedical sensors and radios.
Spacewalk complete. ✅
After 6 hours and 23 minutes outside the International Space Station, @Soph_astro is safely back inside.
With today’s EVA, Sophie becomes the first French woman to perform a spacewalk. 🇫🇷 pic.twitter.com/i3BghrdaRK— European Space Agency (@esa) August 18, 2026
“A successful [spacewalk] starts long before the hatch opens, and that’s where my focus has been these past few days: rehearsing, preparing and focusing,” Adenot said on social media before the excursion.
Suit fitting was a major focus of the preparation: working inside a heavy, pressurised spacesuit for over six hours puts considerable strain on an astronaut’s hands and shoulders, and engineers on the ground worked closely with Adenot to customise her suit and reduce pressure points.
A Milestone for European Space Exploration Adenot brought extensive technical experience to the mission. A trained engineer and former helicopter test pilot, she was selected for astronaut training by the European Space Agency in 2022 and launched to the space station in February 2026, becoming only the second French woman in history to reach space, after physician-astronaut Claudie Haigneré in 1996. With Tuesday’s spacewalk, she also became the second European woman ever to conduct a spacewalk, after Italian astronaut Samantha Cristoforetti in 2022, and the fifth French citizen overall to do so. The last French citizen to walk in space was Thomas Pesquet.
Despite the milestone, Adenot credited the wider team behind the mission. “My deepest gratitude goes to everyone who made this possible — pioneers who came before us, but also the incredible teams working behind the scenes today,” she said after returning inside the station.
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