Einstein's gravitational waves 'seen' from black holes

The Ligo laser interferometers in Hanford, in Washington, and Livingston, in Louisiana, were only recently refurbished and had just come back online when they sensed the signal from the collision. This occurred at 10.51 GMT on 14 September last year.

On a graph, the data looks like a symmetrical, wiggly line that gradually increases in height and then suddenly fades away.

"We found a beautiful signature of the merger of two black holes and it agrees exactly - fantastically - with the numerical solutions to Einstein equations... it looked too beautiful to be true," said Prof Danzmann.
Media captionProf Stephen Hawking: "This provides a completely new way of looking at the universe."

Prof Sheila Rowan, who is one of the lead UK researchers involved in the project, said that the first detection of gravitational waves was just the start of a "terrifically exciting" journey.

"The fact that we are sitting here on Earth feeling the actual fabric of the Universe stretch and compress slightly due to the merger of black holes that occurred just over a billion years ago - I think that's phenomenal. It's amazing that when we first turned on our detectors, the Universe was ready and waiting to say 'hello'," the Glasgow University scientist told the BBC.

Being able to detect gravitational waves enables astronomers finally to probe what they call "dark" Universe - the majority part of the cosmos that is invisible to the light telescopes in use today.