LIGO Document G0900674-v1
- (Talk presented at Sobral Meeting, May 26-29, 2009, Fortaleza (Ceará),Brazil)
General relativity predicts gravity waves that propagate at the speed of light like radio, but sourced by quadrupole and higher moment motion of masses. They have been detected only indirectly, in the quadratically increasing spin down of binary pulsars. Gravity waves distort space-time so one arm of an L-shaped laser interferometer shortens and the other lengthens as the wave passes. Two LIGO interferometers are 3000 km apart and have arms 4 km long. Now about to start a multi-year science run with enhancements to the detector, they are sensitive to length changes of a fraction of an electron's classical diameter over 4 km at audio frequencies. I will introduce the experimental techniques and describe the detectors that have this incredible sensitivity. Gravity waves are emitted by a variety of "contemporary" sources in the universe and they may be present as stochastic relicts of the earliest universe. They are the only potential window to the first moments of the big bang well before the microwave background was formed. I will describe results to date, plans for increased sensitivity, and the world-wide network of detectors now forming with instruments in Europe and Asia.
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