Loudest Gravitational-Wave Burst Maps Black Hole Event Horizon

Researchers analyzing GW250114—the loudest binary black hole merger detected by LIGO, Virgo, and KAGRA—identified a new component called direct waves and used it to probe the remnant black hole's horizon, measuring its rotation frequency and surface gravity; the work, published in Nature, could enable future tests of general relativity and deepen our understanding of what happens at a black hole's edge.