Three scientists who envisioned and built twin machines that discovered gravitational waves, predicted by Albert Einstein more than a century ago, have won the Nobel Prize in physics.
Kip Thorne and Barry Barish of Caltech together split half of the $1.1 million prize, and Rainer Weiss of MIT received the other half. The three were instrumental in the creation of LIGO, the Laser Interferometer Gravitational-wave Observatory, a project some four decades in the making.
Thorne, who was awakened by the Nobel committee around 2:15 a.m. PDT, had to groggily navigate a flight of stairs to the phone ringing loudly in his wife's office.
"My phone never rings around that time of the morning so I was pretty sure what the call was," Thorne said.
Barish said he had set an alarm in anticipation of a call from Nobel officials _ though when it did come at 2:41 a.m., it beat his alarm by 4 minutes.
He said he and his colleagues knew there was a good chance they would be recognized by the Nobel team.
"There was some anticipation," he said. "But the Swedish Academy is so secretive."
The waves were first predicted by Einstein a century ago, but Einstein was convinced they could never be measured. Barish said Tuesday's announcement was "a win for Einstein, and a very big one."
Gravitational waves are ripples in the fabric of space-time, caused as objects accelerate or decelerate. Einstein predicted these waves as part of his General Theory of Relativity, but even he doubted that they would be directly detected.
If gravitational waves were directly measured, they could open a whole new window onto parts of the universe that cannot be seen by any wavelength of light, including such powerful phenomena as colliding neutron stars. But the ripples expected from these cosmic events are so incredibly faint that they seemed practically impossible to detect.
LIGO, co-founded by Thorne, Weiss and Thorne's colleague Ronald Drever, sought to change that.
The laboratory consists of two identical L-shaped detectors, one in Hanford, Wash., the other in Livingston, La. They pick up gravitational waves by measuring how much they squeeze and stretch the detectors' L-shaped arms as the waves pass.
Drever, one of LIGO's co-founders, died in March; the Nobel is only awarded to living scientists.
The project struggled for years to find its footing; Barish, brought in to lead the struggling MIT-Caltech collaboration, was instrumental in getting LIGO designed and built, Thorne said.
With funding from the National Science Foundation, the project finally made its first detection in September 2015: a pair of black holes dancing around and finally colliding into one another, sending out powerful ripples of gravitational wave energy in the process.
Since that initial discovery, LIGO has detected three more black hole collisions. The most recent of these was found in August in collaboration with the European Virgo detector, which has recently come online.
As more gravitational wave observatories join the hunt, the researchers say they expect to narrow in on the location of these powerful events. They may also discover other kinds of gravitational sources, such as the collision between two neutron stars.
And as researchers begin to look beyond the limited band of frequencies in which LIGO operates, they may also be able to learn more about the universe's birth, by looking for gravitational waves from the dawn of the cosmos.
