100 years after Albert Einstein first suggested their existence, scientists have discovered the evidence of gravitational ripples – which stretch space as they travel at the speed of light.
These gravitational waves are ripples in the fabric of space-time that are produced when black holes collide and stars explode – but until now, they had never been directly detected.
Professors David Reitze and Gabriela Gonzalez spoke about their Laser Interferometer Gravitational-wave Observatory project breakthrough, alongside France Cordoba of the National Science Foundation.
Professors David Reitze said, “So these gravitational waves were produced by two colliding black holes.They came together, merged to form a single black hole about 1.3 billion years ago. As they orbit, the black holes are getting closer and closer to one another, the orbit is speeding up and eventually they are going to merge.
“So I want to put this in perspective for you because I think it’s very important to give a sense to what really happened here. Each of these black hole is about 150 kms in diameter, littl bit bigger. Pack 30 times the mass of the sun in that. Accelerate it to about half the speed of light. Now take another thing. 30 times mass of the sun. accelerate it to about half the speed of light and collide them together. That’s what we saw here.”
Professor Reitze described this mind-boggling.
Professor Gabriela Gonzalez said, “We can hear the gravitational waves, we can hear the universe.”
She played the sound of the gravitational waves, which was just a fraction of a second long ‘chirp.’
The detection of the black hole merger was made at 09:50:45 GMT on 14 September.
BBC’s science correspondent Jonathan Amos says that the LIGO lab at Livingston in Louisiana had seen it first. The Hanford, Washington State, observatory 3,000km away sensed the bump seven milliseconds later.
He writes, “The distance to the event, the scientists are pretty confident about; the location, less so. Somewhere in the southern sky.”