It took us 100 years to prove Einstein was right and gravitational waves do exist
A team of scientists have confirmed the existence of gravitational waves that was predicted by Albert Einstein in his general theory of relativity a century ago.
The announcement was made during a press conference held in Washington on Thursday afternoon wherein the scientists said that they had heard and recorded the sound of two black holes colliding a billion light-years away, a fleeting chirp that fulfilled the last prediction of Einstein’s general theory of relativity. The gravitational wave signal was detected by physicists at Laser Interferometer Gravitational-wave Observatory (LIGO) on September 14 last year.
This collision of two black holes had been predicted but never observed.
“This discovery comes at the culmination of decades of instrument research and development, through a world-wide effort of thousands of researchers,” the scientists said.
“It also proves a prediction made 100 years ago by Einstein that gravitational waves exist.
“More excitingly, it marks the beginning of a new era of gravitational wave astronomy – the possibilities for discovery are as rich and boundless as they have been with light-based astronomy.”
Gravitational waves are ripples in spacetime arriving at the Earth from cataclysmic events in the distant universe – like star explosions and black holes crashing into each other. Space is like a giant sheet of rubber. Things that have mass cause that rubber sheet to bend like a bowling ball on a trampoline. The more the mass, the more space gets bent and distorted by gravity.
“Gravitational waves are akin to sound waves that travelled through space at the speed of light,” said gravitational researcher David Blair, from the University of Western Australia. “Up to now humanity has been deaf to the universe. Suddenly we know how to listen. The Universe has spoken and we have understood.”
Besides confirming Einstein’s general theory of relativity, the detection of gravitational waves also amounts to the first direct detection of a pair of colliding black holes, the mysterious structures in space that are so dense they exert a gravitational force from which nothing – not even light – can escape.
“We’re opening a window on the universe, the window of gravitational wave astronomy. It’s the first time the Universe has spoken to us in gravitational waves. This was a scientific moonshot and we did it. We landed on the Moon,” said David Reitze, executive director of the US’s Laser Interferometer Gravitational Wave Observatory (LIGO).
The new Advanced LIGO detectors had just been brought into operation for their first observing run when the very clear and strong signal was captured on 14 September 2015 at 5.51am Eastern Daylight Time (10.51am GMT).
Based on the observed signals, LIGO scientists confirmed they had detected unambiguous signals of gravitational waves emanating from the collision of two massive black holes 1.3 billion light years away in deep space.
As the two black holes spiralled together in a violent collision that was over in 20 thousandths of a second, huge amount of matter equivalent to the mass of three suns were instantly converted into energy.
“Our observation of gravitational waves accomplishes an ambitious goal set out over 5 decades ago to directly detect this elusive phenomenon and better understand the universe, and, fittingly, fulfills Einstein’s legacy on the 100th anniversary of his general theory of relativity,” said Caltech’s David H. Reitze, executive director of the LIGO Laboratory.
The first gravitational-wave signal was picked up at the LIGO’s Hanford observatory in Washington State and then, seven thousands of a second later, an identical signal was picked up at LIGO’s Livingston site in Louisiana some 2,000 miles away.
Professor Gabriela Gonzalez of Louisiana State University, the spokesperson for LIGO said, “You can only believe they are real if you observe them at the same time in two different places.”
The discovery was accepted for publication in the journal Physical Review Letters, reinforcing its credibility.