What Colliding Black Holes Sound Like | Video

When a pair of black holes – each about 30x our sun's mass – collided 1.3 billion years ago, the event sent gravitational waves rippling across the universe. They were 'heard' by a pair of laser interferometers on 14 September 2015. In this waveform animation, the first two passes are played at the actual frequencies of the event; the second pair are shifted up into the 'sweet spot' of human hearing. Read the Full Story: http://www.space.com/31900-gravitational-waves-discovery-ligo.html

credit : LIGO