LIGO stands for Laser Interferometer Gravitational-Wave Observatory. Cofounded in 1992 by Ronald Drever , of CalTech and Rainer Weiss, of MIT. LIGO is a joint project between scientists at the Massachusetts Institute of Technology (MIT)and the California Institute of Technology (Caltech), sponsored by the National Science Foundation (NSF). At the cost of $365 million (in 2002 USD), it has been the largest, the most ambitious project ever funded by NSF (and still is as of 2004). The international LIGO Scientific Collaboration (LSC) is a growing group of researchers, some 400 individuals at roughly 40 institutions, working to analyze the data from LIGO and other detectors, and working toward more sensitive future detectors.
LIGO's mission is to observe the theoretical gravitational waves of cosmic origin. In summer 2004, LIGO began its search for cosmic gravitational waves that are theoretically created in supernova collapses of stellar cores (which form neutron stars and black holes), collisions and coalescences of neutron stars or black holes, rotations of neutron stars with deformed crusts and the remnants of gravitational radiation created by the birth of the universe.
The Livingston Observatory , located in Livingston, Louisiana facility houses a laser interferometer, consisting of mirrors suspended at each of the corners of a gigantic L-shaped vacuum system, measuring 4 kilometers (2.5 miles) on each side. Precision laser beams in the interferometer sense small motions of the mirrors, which are caused by gravitational waves.
The Hanford Observatory , located near Richland, Washington on the Hanford Nuclear Reservation, houses a nominally identical laser interferometer as the Livingston Observatory. Also, there is a smaller, though no less complicated, interferometer housed in parallel. This second detector is half the length (2 kilometers), and thus half as sensitive.
The theoretical gravitational waves that originate hundreds of millions of light years from Earth are expected to distort the 4 kilometer mirror spacing by about 10-18 m (a hydrogen atom is about 5×10-11 m). These waves were first predicted by Einstein's Theory of General Relativity in 1916, when the technology necessary for their detection did not yet exist. Now, at the turn of the 21st century, we believe technology has reached the point where detection of gravitational waves is possible.
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