Physicists Rainer Weiss, Kip Thorne and Barry Barish received the 2017 Nobel prize in physics for their work detecting ripples in space-time predicted by Einstein over 100 years ago.
Why it matters: Einstein's theory of general relativity predicts that massive objects — like black holes — distort space-time. We feel that as gravity. Because space-time can't be directly seen or measured, scientists instead study it indirectly, for example by searching for gravitational waves that Einstein predicted would be emitted when two massive objects collide. So far, observations by the Laser Interferometer Gravitational-Wave Observatory have confirmed Einstein's theory.