Gravitational wave signal proves Einstein was right about relativity
The loudest collision ever recorded between two black holes has allowed scientists to test Einstein’s theory of general relativity in unprecedented detail, showing that the physicist’s predictions were once again correct. In 2025, an international collaboration of gravitational wave detectors, made up of ultra-sensitive laser arrays, detected a powerful ripple in the fabric of space-time, labelled GW250114, probably produced by the merger of two black holes. The detectors, which include the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the US and the Virgo detector in Italy, are far more sensitive than when LIGO made its first detection in 2016. This meant that GW250114 had the clearest and most noise-free data of any gravitational wave event so far, making it a unique testbed for predictions from otherwise well-tested physical theories. Last year, researchers used data from GW250114 to test Stephen Hawking’s theorem, proposed more than 50 years ago, that a merged black hole’s event horizon, the region within which light can no longer escape, would not be smaller than the sum of its parent black holes. The …
