Introduction to LIGO & Gravitational Waves
Detecting Gravitational Waves
Aerial view of the LIGO detector in Hanford,
WA. [Image: LIGO]
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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).
