Introduction to LIGO & Gravitational Waves

Detecting Gravitational Waves


Aerial view of the LIGO detector in Hanford, WA. [Image: LIGO]

LIGO Hanford Observatory, WA
Gravitational waves interact with matter by compressing objects in one direction while stretching them in the perpendicular direction.  Therefore, the current state-of-the-art gravitational wave detectors are L-shaped and measure the relative lengths of the arms using interferometry, which looks at the interference patterns produced by the combination of two light sources.  There are two such interferometers in the United States — one in Hanford, Washington and the other in Livingston, Louisiana — and they are collectively called LIGO (Laser Interferometer Gravitational-wave Observatory).  LIGO is the largest of the gravitational wave detectors with arms 4 km (a little less than 2.5 miles) in length interferometers (the international detectors include VIRGO in Italy, GEO in Germany and TAMA in Japan).

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