After 100 years of searching, an international team of physicists has confirmed the existence of Einstein’s gravitational waves, marking one of the biggest astrophysical discoveries of the past century. It’s a huge deal, because it not only improves our understanding of how the Universe works, it also opens up a whole new way of studying it.
The gravitational wave signal was detected by physicists at LIGO on September 14 last year, and the historic announcement was made at a press conference this morning. Experts are already saying the discovery is a shoo-in for a Nobel Prize
Gravitational waves are so exciting because they were the last major prediction of Einstein’s general theory of relativity that had to be confirmed, and discovering them will help us understand how the Universe is shaped by mass.
“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.”
What does that mean for us? Just think of all the breakthroughs that have come thanks to the discovery of x-rays and radio waves – now that we can detect gravitational waves, we’re going to have a whole new way to see and study the Universe.
But let’s step back for a second here and explain what gravitational waves actually are. According to Einstein’s theory, the fabric of space-time can become curved by anything massive in the Universe. When cataclysmic events happen, such as black holes merging or stars exploding, these curves can ripple out elsewhere as gravitational waves, just like if someone had dropped a stone in a pond.
By the time those ripples get to us on Earth, they’re tiny (around a billionth of the diameter of an atom), which is why scientists have struggled for so many years to find them.
But thanks to LIGO – the laser interferometer gravitational-wave observatory – we’ve finally been able to detect them. The LIGO laboratory works by bouncing lasers back and forth in two 4-km-long pipes, allowing physicists to measure incredibly small changes in spacetime.
One 14 September 2015, they picked up a relatively big change in their Livingston lab in Louisiana, what you’d call a blip in the system. Then, 7 milliseconds later, they detected the same blip with their lab in Hanford, Washington, 4,000 km away, suggesting that it had been caused by a gravitational wave passing through Earth. Continue Reading