Evolution and Structure of the Universe Ripples In Space And Time
LIGO Hanford Observatory LIGO Livingston Observatory

To detect the very weak waves predicted, LIGO will use a four-foot diameter vacuum pipe, with 2.5 mile long L-shaped arms. Test masses will hang from wires at the vertex of the L. Gravity waves will cause minute changes in the distance between the test masses, which will be measured by ultrastable laser beams traversing the vacuum pipes.

Two LIGO facilities are under construction, one in Louisiana, one in Hanford, Washington. The project needs two widely separated detectors to insure against spurious local effects - such as micro-earthquakes, acoustic noise and laser fluctuations - that could create local disturbances resembling a gravity wave event.

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Revised: August 21, 1998

URL: http://www.psc.edu/science/Winicour/winicour.html