Today is the 9th anniversary of the first detection of gravitational waves
September 14, 2015 — the first chirp
The Laser Interferometer Gravitational-Wave Observatory (LIGO) first detected a gravitational wave chirp on September 14, 2015. The chirp was caused by the merger of two black holes that were 29 and 36 times the mass of the Sun. The collision occurred about 1.3 billion years ago.
Comparing “Chirps” from Black Holes (audio/video)
