Guardian: The event marks only the second time that scientists have spotted gravitational waves, the tenuous stretching and squeezing of spacetime predicted by Einstein more a century ago. by Ian Sample
'The faint signal received by the twin instruments of the Laser Interferometer Gravitational Wave Observatory (LIGO) in the US revealed two black holes circling one another 27 times before finally smashing together at half the speed of light.
'The cataclysmic event saw the black holes, one eight times more massive than the sun, the other 14 times more massive, merge into one about 21 times heavier than the sun. In the process, energy equivalent to the mass of the sun radiated into space as gravitational waves.
'“This is confirmation that there’s a real population of black holes out there waiting to be detected in the future,” said John Veitch, an astrophysicist on the LIGO team at the University of Birmingham.'