2017 Nobel Prize in Physics
Reason for Award
for decisive contributions to the LIGO detector and the observation of gravitational waves
Laureates
United States of America
United States of America
United States of America
Explanation
When something huge happens in space, tiny ripples spread out like waves on a pond. These ripples are called “gravitational waves.” Rainer Weiss, Barry Barish, and Kip Thorne built a giant instrument in the United States named LIGO and were the first to catch those waves directly. Detecting gravitational waves is like listening to the universe’s hidden “sounds.” Thanks to their work, we now have a new way to learn about events we cannot see, such as two black holes crashing together.
Related Keywords
gravitational wave
A ripple in spacetime generated when massive objects accelerate. It propagates at light speed and alternately stretches and squeezes space. Detecting it requires ultra-sensitive interferometers because its amplitude over Earth-scale baselines is smaller than a nucleus.
laser interferometer
An instrument that splits a laser beam into two perpendicular paths and measures minuscule length differences via interference fringes. In LIGO, 4-km arms and multiple reflections amplify sensitivity by hundreds of times.
binary black hole merger
A system where two black holes lose orbital energy via gravitational-wave emission, eventually colliding and merging. The final few hundred milliseconds produce intense gravitational waves.
general relativity
Einstein’s 1915 theory describing gravity as the curvature of spacetime. It predicts gravitational waves and black holes, and LIGO observations confirm its validity in strong-gravity regimes.
matched filtering
An analysis technique that cross-correlates observed data with theoretical waveform templates to extract faint signals. LIGO uses hundreds of thousands of templates to maximize signal-to-noise.
signal recycling
An optical technique that places a mirror at the interferometer’s output port to enhance sensitivity in a chosen frequency band. Employed in Advanced LIGO to tune frequency response.
squeezed light
Light with reduced quantum uncertainty in either phase or amplitude by redistributing noise—used to lower interferometer shot noise in future upgrades.
multi-messenger astronomy
A field combining electromagnetic, gravitational-wave, neutrino, and other observations to study cosmic events. The advent of gravitational-wave detection broadened its scope.
Fabry–Pérot cavity
An optical resonator formed by two highly reflective mirrors. Installed in interferometer arms to effectively lengthen the light path and boost sensitivity.
seismic isolation
Technology that attenuates ground motion by factors of tens of millions. In LIGO, multi-stage pendulums and active controls stabilize mirror positions.