Barry C. Barish, is an American physicist who was awarded the 2017 Nobel Prize in Physics for his work on the Laser Interferometer Gravitational Wave Observatory (LIGO) and the first direct detection of gravity waves. He shared the prize with American physicists Rainer Weiss and Kip Thorn.
Barish received his bachelor's and doctorate in physics at the University of California, Berkeley, in 1957 and 1962, respectively. He was a research fellow at Berkeley from 1962 to 1963 and then became a research fellow at the California Institute of Technology (Caltech), where he spent the remainder of his career. He became professor emeritus in 2005.
Barish began his career in high-energy physics. He worked on experiments at the Stanford Linear Accelerator Center, and in the 1980s he became involved in the search for magnetic monopoles. He also headed a team to design an experiment for the Superconducting Super Collider (SSC), a giant particle accelerator to be built in Texas, but the U.S. Congress canceled that project in 1993.
After the cancellation of the SSC, Barish became LIGO principal investigator in 1994. The NSF in its 1992 and 1993 reviews of LIGO had expressed doubts about its feasibility and management structure. Barish instituted technical changes to LIGO's design, such as using solid-state lasers, which were more powerful than the originally planned argon gas lasers. LIGO was run mainly as a small collaboration between Caltech and MIT. Barish realized that LIGO would need permanent staff and many more scientists to help in what was an extremely technically demanding project. In 1997 he established the LIGO Scientific Collaboration (LSC), a team of hundreds of scientists from around the world. That same year Barish became LIGO director. Barish's changes pleased the NSF, which funded LIGO at a much higher level, and were credited with doing much to make LIGO a success.
Construction began on LIGO's two interferometers at Livingston, Louisiana, and Hanford, Washington, in 1994, and observations began in 2002. Although LIGO had not detected any gravity waves in its early years, Barish pushed through plans for an upgraded version, Advanced LIGO, that would. Advanced LIGO was approved by the NSF in 2004, and it was completely installed in 2014. On September 14, 2015, Advanced LIGO made the first detection of gravity waves from a pair of black holes that spiraled into each other 1.3 billion light-years away.
Barish stepped down as LIGO principal investigator and was director from 2005 to 2013 of the Global Design Effort of the International Linear Collider, a proposed 31-kilometre- (19-mile-) long linear particle accelerator.