It wasn’t until nearly a century after his 1916 paper that an international team of more than 1,000 scientists proved that Einstein was indeed right in that gravitational waves exist, but wrong in assuming we could never detect them. At 5:50:45 a.m. EDT on September 14, 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) picked up the faint yet unmistakable rumbles of gravitational waves emanating from colliding black holes containing 36 and 29 solar masses.
LIGO’s discovery opened a window on the universe, creating a revolutionary new branch of science that can obtain information on nature’s most extreme events — events that would otherwise be hidden from view. Since colliding black holes generate no form of light, we can discern these cosmic cataclysms only from the way they contort the fabric of space-time.
In a mere fraction of a second, the black hole collision detected by LIGO converted about three times the mass of the Sun into gravitational-wave energy — with a peak power output of nearly 50 times that of the entire visible universe. But these waves diminished rapidly in intensity as they traversed space. By the time they reached Earth, after a journey that took about 1.3 billion years, they expanded and contracted space-time by 1/10,000 the width of a proton. It’s no wonder Rainer Weiss, Kip Thorne, and Barry Barish, three of LIGO’s key figures, shared the 2017 Nobel Prize in Physics: Detecting these minuscule fluctuations required a precision akin to measuring the 25 trillion-mile distance to the nearest stars to the width of a human hair.