Virgo

Virgo is a Franco-Italian experiment near Pisa designed to detect and measure gravitational waves created by violent astrophysical events. This experiment is based on the Michelson interferometry principle, with 3 km long arms.

A passing gravitational wave changes the relative length of the arms and modifies the interference pattern. Virgo joined LIGO (Laser Interferometer Gravitational-Wave Observatory at the MIT) for a joint detection run in 2007 and is currently running day and night.