Black holes may be the fiercest objects in the universe, yet we still know very little about them. It has only been a decade since we confirmed their existence by detecting gravitational waves: ripples in the fabric of spacetime.

Since then, gravitational waves from colliding black holes have unveiled insights into their hidden physics and the theories that support them. On January 14, 2025, the loudest gravitational-wave signal ever detected, known as GW250114, was observed by the two Laser Interferometer Gravitational Wave Observatories (LIGO).

This remarkable event provided our international team of scientists with a golden opportunity to test two major predictions of Albert Einstein’s theory of general relativity with unprecedented precision: the nature of black holes and something called Hawking’s area law theorem.

The results, published in Physical Review Letters, mark a significant step forward in our understanding of gravity and black holes.

Black holes are a key prediction of general relativity, our leading theory for describing gravity.........

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