Gravitational Waves Discovered: A New Window on the Universe

An illustration of Markarian 231, a binary black hole 1.3 billion light years from Earth. Their collision generated the first gravitational waves we've ever detected. Image: NASA

“Ladies and Gentlemen, we have detected gravitational waves. We did it.”With those words, Dave Reitze, executive director of the U.S.-based Laser Interferometry Gravitational-Wave Observatory (LIGO), has opened a new window into the universe, and ushered in a new era in space science.Predicted over 100 years ago by Albert Einstein, gravitational waves are ripples in space-time. They travel in waves, like light does, but they aren’t radiation. They are actual perturbations in the fabric of space-time itself. The ones detected by LIGO, after over ten years of “listening”, came from a binary system of black holes over 1.3 billion light years away, called Markarian 231.The two black holes, each 30 times as massive as the Sun, orbited each other, then spiralled together, ultimately colliding and merging together. The collision sent gravitational waves rippling through space time.LIGO, which is actually two separate facilities separated by over 3,000 km, is a finely tuned system of lasers and sensors that can detect these tiny ripples in space-time. LIGO is so sensitive that it can detect ripples 10,000 times smaller than a proton, in laser beams 4 kilometres long.Light is—or has been up until now—the only way to study objects in the universe. This includes everything from the Moon, all the way out to the most distant objects ever observed. Astronomers and astrophysicists use observatories that can see in not only visible light, but in all other parts of the electromagnetic spectrum, to study objects in the universe. And we’ve learned an awful lot. But things will change with this announcement.”I think we’re opening a window on the universe,” Dave Reitze said.Another member of the team that made this discovery, astrophysicist Szabolcs Marka from Columbia University, said, “Until this moment we had our eyes on the sky and we couldn’t hear the music.”Gravitational waves —> Read More