Template:POTD/2019-06-15
A binary black hole is a system consisting of two black holes in close orbit around each other. For many years, proving the existence of such binaries was made difficult because of the nature of black holes themselves and the limited means of detection available. However, in the event that a pair of black holes were to merge, an immense amount of energy should be given off as gravitational waves, with distinctive waveforms that can be calculated using general relativity.
This video is a computer simulation of the binary black hole system GW150914 during its final inspiral, merge and ringdown, as it would have been seen by a nearby observer. The star field behind the black holes is heavily distorted and appears to rotate and move, due to extreme gravitational lensing caused by spacetime being warped by the orbiting black holes. This event, observed by LIGO in 2015, was the first observation of a binary black hole merger, as well as the first direct detection of gravitational waves, confirming Einstein's predictions.Video credit: Simulating eXtreme Spacetimes