On May 21, 2019, Earth was caught in a surging swell of the cosmic sea. A gravitational wave, a ripple in the fabric of space-time, washed over the planet, pinging a trio of laser detectors on the surface of our planet. The wave was caused by a collision between two huge black holes in a deep corner of space. 

Today, astronomers have announced it is officially the biggest collision ever detected, forming a black hole 150 times more massive than the sun.

Details of the event, dubbed GW190521, were published in two prominent astrophysics journals on Wednesday, and they come from the LIGO/Virgo collaboration, a huge team of scientists studying gravitational waves detected by the dual Laser Interferometer Gravitational-Wave Observatory facilities in the US and the Virgo detector in Italy.