The Nobel Prize for Physics has been awarded to Rainer Weiss, Barry C. Barish and Kip S. Thorne, for “decisive contributions to the LIGO detector and the observation of gravitational waves”, and by doing so opening a new window to the unknown universe.

One half of the 8 million Swedish kronor (roughly $980,000) prize was awarded to Rainer Weiss, professor of physics emeritus at MIT, who co-founded the LIGO project and led the detector design, inventing the laser interferometric technique around which the LIGO instrument was built.

The other half was shared equally by two scientists. Barry C. Barish, Linde Professor of Physics, emeritus, California Institute of Technology, who led the scaling up of the project to reach the level of sensitivity required for successful detections. And Kip S. Thorne, Professor of Theoretical Physics, California Institute of Technology, who co-founded the LIGO project and predicted the expected signals from different astrophysical events that would be transmitted as gravitational waves.

Two black holes colliding; gravitational waves rippling outwards
Image: LIGO/T. Pyle

Gravitational waves are ripples in space-time that emanate from massive bodies that are undergoing acceleration. So far all detections on Earth have been from the conclusion of the deadly orbital dance of two black holes moving closer and closer to one another before they finally collide and merge, forming an even larger black hole. Following this, gravitational waves spread outwards through space at the speed of light causing space to alternately stretch and contract at right angles to the direction that wave is travelling in.

Despite the cataclysmic nature of the events involved, the signal from gravitational waves is tiny and it took what has been described by the Nobel Committee as “perhaps the most sensitive instrument ever devised by man” to detect them.

Since the first detection on 14 September 2015, three more detections of gravitational waves have been recorded. The most recent, just last week, was jointly observed by LIGO and its sister detector in Italy, Virgo. Described by the Nobel Committee as “the dawn of a new field”, gravitational wave astronomy has the potential to reveal entirely new insights into the most violent processes in the universe such as supernovae, gamma ray bursts or perhaps even the Big Bang.