Rainer Weiss

Rainer Weiss developed the practical laser interferometer concept that became central to LIGO. The two Advanced LIGO detectors in Hanford, Washington and Livingston, Louisiana use 4 km arms to measure tiny changes in distance caused by gravitational waves.

Weiss shared the 2017 Nobel Prize in Physics with Kip Thorne and Barry Barish for decisive contributions to LIGO and the observation of gravitational waves. LIGO's first detection, GW150914, came from merging black holes and was announced publicly in February 2016.

Weiss is best known as an experimental physicist. At MIT, he worked on precision measurement problems, including the noise sources that would make or break laser interferometer gravitational-wave detection.

Einstein's general relativity predicted gravitational waves in 1916, but they were not directly detected for almost a century. Weiss helped design the kind of instrument that finally measured them through LIGO in 2015.