Tejaswi Venumadhav

Two neutron stars are two city-sized spheres with the mass of the Sun. As they spiral together, tidal forces stretch each one, as if a giant hand were squeezing and twisting a rugby ball. The star begins to oscillate — density waves run through it, like ripples on water from a thrown stone.

When black holes collide, the very fabric of spacetime trembles. That rumble, gravitational waves, gets picked up by detectors, but decoding the signal used to take hours of computer simulation.

On November 23, 2023, LIGO detectors caught something strange. The gravitational wave signal from a black hole merger, designated GW231123, pointed to record masses—137 and 101 solar masses, and anomalously fast spin. That would be the most massive and fastest-spinning pair ever detected.