ROBERT SIEGEL, HOST:
Today, three scientists won the Nobel Prize in physics for their role in building a device that can detect gravitational waves. The award came quickly, just two years after these waves were detected for the very first time. NPR science correspondent Joe Palca has more.
JOE PALCA, BYLINE: A century ago, Albert Einstein overturned the conventional view of space with his theory of general relativity. Instead of thinking of space as flat, he conceived of it as something that was curved. And with that insight, he was able to make a number of predictions, including the existence of gravitational waves.
KIP THORNE: A gravitational wave can be thought of as a ripple in the shape of space that propagates to the universe much like ripples on the surface of a pond.
PALCA: Physicist Kip Thorne of the California Institute of Technology is one of this year's Nobel laureates, along with Barry Barish, also at Caltech, and MIT physicist Rainer Weiss. Thorne says as these ripples pass by at the speed of light, they stretch and squeeze everything in their path.
THORNE: That stretching and squeezing of space stretches and squeezes, then, the objects that live in space.
PALCA: Now, the stretching and squeezing is infinitesimal, so small that Einstein thought it would be impossible to detect. Thorne felt otherwise.
THORNE: I became convinced in 1975 that it should be possible to detect gravitational waves.
PALCA: So he and others conceived of LIGO, the Laser Interferometer Gravitational-Wave Observatory. It's shaped like a giant L - two 2 and a half mile-long measuring sticks at right angles to each other. If a gravitational wave sweeps by, those arms should get stretched or squeezed in a way the laser beam can measure. In September 2015, LIGO saw just that - a gravitational wave generated by two black holes smashing together.
THORNE: My reaction was just one of profound satisfaction.
PALCA: Thorne's colleague Barry Barish had a different reaction to that first detection.
BARRY BARISH: It put me into a deep state of worry. You know, how are we either fooling ourselves or being fooled?
PALCA: As I said, the change in the length of the measuring sticks caused by the wave is extremely small. Errors are easy to make. Barish says they even worried about sabotage.
BARISH: Was it somehow a rogue event, meaning someone got into our data stream somewhere and planted it?
PALCA: But then a few months later, Barish says LIGO detected a second wave, also coming from merging black holes.
BARISH: I have to admit that for me, I had a sigh of relief when we had the second event.
PALCA: Barry Barish expects LIGO will detect many more gravitational waves and not just from known events like merging black holes or colliding neutron stars.
BARISH: I can't imagine that there isn't going to be some enormous surprises - things that have nothing to do with what we already know.
PALCA: A new view of the universe lies ahead. Joe Palca, NPR News.
(SOUNDBITE OF UYAMA HIROTO'S "YIN AND YANG") Transcript provided by NPR, Copyright NPR.
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