The loudest crash of gravitational waves ever heard has offered us insight into event horizons, the boundaries beyond which nothing can escape the grips of black holes.
The gravitational wave signal GW250114 was picked up in January 2025 by LIGO (Laser Interferometer Gravitational-Wave Observatory), Virgo, and KAGRA ( Kamioka Gravitational Wave Detector). The signal was created when two black holes with around 32 times the mass of the sun collided and set the very fabric of space rippling.
Now, a team of researchers assessed this signal and found a feature in the gravitational waves represents the collective event horizon of the involved black holes at the very moment of that collision.
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