Aerial views of the LIGO Livingston (top left) and Hanford (bottom left) observatories. At right, 90 gravitational wave events are depicted in this chart, arranged by their date of detection between September 2015 and March 2020. Visit for more charts like this, and other fun interactive plots!

LIGO - A Gravitational-Wave Observatory

LIGO, the U.S. National Science Foundation Laser Interferometer Gravitational-wave Observatory, consists of two instruments called interferometers, each with two 4km-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 NSF LIGO actually works.