Physicists have detected the biggest ever merger of colliding black holes. The discovery has major implications for researchers’ understanding of how such bodies grow in the Universe.

“It’s super exciting,” says Priyamvada Natarajan, a theoretical astrophysicist at Yale University in New Haven, Connecticut, who was not involved in the research. The merger was between black holes with masses too big for physicists to easily explain. “We’re seeing these forbidden high-mass black holes,” she says.

The discovery was made by the Laser Interferometer Gravitational-Wave Observatory (LIGO), a facility involving two detectors in the United States. It comes at a time when US funding for gravitational-wave detection faces devastating cuts. The results, released as a preprint on the arXiv server¹, were presented at the GR-Amaldi gravitational-waves meeting in Glasgow, UK, on 14 July.

Join us as we journey beyond the birth of the universe to unravel the mysteries of what might have preceded the Big Bang—and whether time itself had a beginning.

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Credits:
Before the Big Bang — What Came Before Time?
Episode 738; July 20, 2025
Written, Produced & Narrated by: Isaac Arthur.
Select imagery/video supplied by Getty Images.
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator.
0:00 Intro Asking the Impossible.
2:08 The Limits of Time and Spacetime.
7:45 Beyond the Big Bang: Alternate Beginnings.
14:38 Other Realities: Higher Dimensions and Shadow Universes.
18:28 Emergent Time.
22:38 Bubble Collisions and Multiverse Scars.
24:44 Conclusion: What Came Before Time?

Dark matter is being thrown off the table with this new theory — simpler, and it relies on something that can be seen. Cosmic studies are about to change.

Instead of the big bang, some physicists have suggested that our universe may have come from a big bounce following another universe contracting – but quantum theory could rule this out

The sPHENIX particle detector, the newest experiment at the Relativistic Heavy Ion Collider (RHIC) at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, has released its first physics results: precision measurements of the number and energy density of thousands of particles streaming from collisions of near-light-speed gold ions.

As described in two papers recently accepted for publication in Physical Review C and the Journal of High Energy Physics, these measurements lay the foundation for the detector’s detailed exploration of the quark–gluon plasma (QGP), a unique state of matter that existed just microseconds after the Big Bang some 14 billion years ago. Both studies are available on the arXiv preprint server.

The new measurements reveal that the more head-on the nuclear smashups are, the more charged particles they produce and the more total energy those firework-like sprays of particles carry. That matches nicely with results from other detectors that have tracked QGP-generating collisions at RHIC since 2000, confirming that the new detector is performing as promised.

Scientists observe the most massive merger event yet, with the colliding black holes lying in a mass range that is incompatible with the standard stellar-formation scenario.

I have for a long time been searching for applications of the philosophy of Wittgenstein, particularly later Wittgenstein, to physics. I believe I have found that application in the work of Peter Putnam, who, building on the philosophy of Sir Arthur Eddington, Everett (of Many Worlds fame), and John Wheeler, constructed, in his private musings, the beginnings of a verbal, syntactical representation theory for quantum physics.

There have been a couple of articles lately about Putnam, starting with this one in Nautilus less than a month ago.

He was a relatively unknown figure who might have been as famous as Wittgenstein himself if not for a meddling mother.

A cosmic void could be distorting how we see the universe expand. Sound from the Big Bang may hold the clues. According to astronomers, Earth and the entire Milky Way galaxy might be located within a vast, low-density region of space—essentially a cosmic void—that causes the universe to expand mo

Instead of a tempest in a teapot, imagine the cosmos in a canister. Scientists have performed experiments using nested, spinning cylinders to confirm that an uneven wobble in a ring of electrically conductive fluid like liquid metal or plasma causes particles on the inside of the ring to drift inward. Since revolving rings of plasma also occur around stars and black holes, these new findings imply that the wobbles can cause matter in those rings to fall toward the central mass and form planets.

The scientists found that the wobble could grow in a new, unexpected way. Researchers already knew that wobbles could grow from the interaction between plasma and magnetic fields in a gravitational field. But these new results show that wobbles can more easily arise in a region between two jets of fluid with different velocities, an area known as a free shear layer.

“This finding shows that the wobble might occur more often throughout the universe than we expected, potentially being responsible for the formation of more solar systems than once thought,” said Yin Wang, a staff research physicist at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) and lead author of the paper reporting the results in Physical Review Letters. “It’s an important insight into the formation of planets throughout the cosmos.”

In addition to their high masses, the black holes are also rapidly spinning.

“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,” says Mark Hannam of Cardiff University and a member of the LVK Collaboration. “Black holes this massive are forbidden through standard stellar evolution models. One possibility is that the two black holes in this binary formed through earlier mergers of smaller black holes.”