More than a billion years ago, two black holes—the gravitational ghosts of gigantic stars—spiraled together and collided in space. Ripples in spacetime swept through the universe. Five months ago, they washed past Earth, and physicists detected gravitational waves for the first time. The long-awaited discovery—announced this week—marks a triumph for the Laser Interferometer Gravitational-Wave Observatory (LIGO), a pair of huge instruments in Washington state and Louisiana. It also promises to give researchers a whole new set of eyes on the universe. Until now, astronomers have probed it mainly through electromagnetic radiation such as light. Now, gravitational waves will enable them to detect astrophysical objects that they can't see. And physicists will be able to study realms of extreme gravity that until now only theorists could explore. Other gravitational-wave detections may come soon, both from LIGO and from VIRGO, a freshly upgraded Italian detector scheduled to be switched on later this year.
Triumph for gravitational wave hunt
Science 12 Feb 2016:
Vol. 351, Issue 6274, pp. 645-646