Around 100 years ago, the genius Albert Einstein predicted “gravitational waves” – ripples in “spacetime” around the universe created by black holes colliding billions of years ago. He nearly predicted Star Wars, too.
Until today, the physicist’s workings had not been confirmed. But on Thursday 11 February, science confirmed it. Scientists have detected gravitational waves for the first time.
The discovery was made at the Laser Interferometer Gravitational Wave Observatory (LIGO) in the US. It’s been a long-term mission, and to complete the task, the world’s most precise device to measure wave frequencies had to be constructed.
The project began more than two decades ago, in 1992. A huge investment was made into the study. It looks that now, finally, it’s paid off.
“This was a scientific moon shot,” LIGO Laboratory executive director, David Reitze, explained at a conference this morning.
“And we did it – we landed on the moon.”
This image is from NASA. You’ll find a more detailed explanation of gravitational waves here.
The instrument that detected the waves consists of two 2.5-mile tunnels in Louisiana and Washington State. Inside these, the ‘measuring stick’ used by the scientists was the speed of light, which is constant. It means the length of the tunnels can be clearly identified and, as such, the waves too.
TechCrunch explains how the gravitational waves were subsequently captured using the tunnels and light.
The “ruler” that scientists used to measure these tunnel lengths was the speed of light. The speed of light is constant, so LIGO can determine the length of the tunnels by measuring the time it takes for a laser to bounce from one end of the tunnel to the other.
Gravitational waves are created when masses accelerate. Measured back on September 14, 2015, the gravitational wave signal that the LIGO scientists detected matches the exact signal they’d expect from two merging black holes accelerating at half the speed of light.
Interestingly, and as you may have noted, LIGO researchers actually found out that gravitational waves exist half a year ago. Yet it took all this time to check and explore every possibility for the findings before announcing the historic news.
The time it took to tell the world about the waves, however, was not nearly as long as the time it took for the gravitational wave to reach Earth. The first one detected started its journey 1.3 billion years ago.
This finding is a big deal for many. It’s certainly huge for astronomy. It will allow scientists to explore the universe in a whole new way.
“This is the first time the universe has spoken to us through gravitational waves,” Reitze added.
“Up until now we’ve been deaf to gravitational waves. Today, we’re able to hear them.”
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