Bio:    Barry Barish is the Linde Professor of Physics, Emeritus, at the California Institute of Technology.  He is a leading expert on gravitational waves, having led the Laser Interferometer  Gravitational-Wave Observatory(LIGO) project as the principal investigator and director from the beginning of construction in 1994 until 2005.  During that period, LIGO detectors reached design sensitivity and set many significant limits on astrophysical sources.  The more sensitive Advanced LIGO proposal was developed and approved while Barish was director, and he continues  to play an active leading role in LIGO.  His other noteworthy experiments include an experiment at Fermilab using high-energy neutrino collisions to reveal the quark substructure of the nucleon.  These experiments were among the first to observe the weak neutral current, a linchpin of the electroweak unification theories of Glashow, Salam, and Weinberg.  Barry Barish is also the former director of the Global Design Effort for the international Linear Collider(ILC), the highest priority future project for particle physics worldwide.

Abstract:  In  his 2000 Buhl Lecture, Barry Barish, then the director of LIGO, discussed gravitational waves, the ripples in the fabric of space and time whose existence was predicted by Einstein in 1916.  At the  time, LIGO had recently been constructed under Barish’s leadership and had begun to collect data.  On February 11, 2016, it was announced that LIGO’s upgraded detectors had made the first-ever observation of gravitational waves from a pair of merging black holes.  Barish returns to CMU for an encore Buhl Lecture in which  he will discuss the physics of gravitational waves, the techniques used to detect gravitational waves, and the implications of the new observations.