Albert Einstein predicted the existence of gravitational waves --- ripples in the fabric of space and time --- as part of the general theory of relativity. The Laser Interferometer Gravitational Wave Observatory (LIGO) is designed to detect these waves directly, opening up a new vantage point from which to study the universe.
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Artist's
view of 2 binary neutron stars just before they collide.
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LIGO is a national research facility designed by a team of scientists and engineers from the California Institute of Technology and the Massachusetts Institute of Technology. Two LIGO Observatory facilities have been constructed --- near Livingston, Louisiana and on the Hanford Reservation near Richland, Washington. Each facility has a giant L-shaped antenna 8 kilometers from end to end. Within these antennae, extremely precise lasers and optics operating in ultra-high vacuum measure the stretching and squeezing of space time induced by passing gravitational waves. This effect is so slight that differential variations in end-to-end arm length as small as one ten-thousandth the diameter of a proton can be sensed.
When operational, LIGO will allow scientists to understand the astrophysical sources of gravitational waves, including supernovae, binary neutron star systems, and the vibration of black holes.