Aerial views showing the locations and extents of the LIGO Hanford and LIGO Livingston interferometers.

LIGO - A Gravitational-Wave Interferometer

LIGO consists of two instruments called interferometers, each with two 4 km (2.5 mile) long arms arranged in the shape of an “L”. The interferometers act as 'antennae' to detect gravitational waves. In the links below, you will learn much more about interferometers and how LIGO actually works.