Ligo is made up of two observatories that detect gravitational waves by splitting a laser beam and sending it down several mile (kilometre) long tunnels before merging the light waves together again.
A passing gravitational wave changes the shape of space by a tiny amount, and the Ligo was built with the ability to measure a change in distance just one-ten-thousandth the width of a proton.
However, this sensitivity means any amount of noise, even people running at the site, or raindrops, can be detected.
The Ligo detectors are interferometers that shine a laser through a vacuum down two arms in the shape of an L that are each 2.5 miles (four kilometres) in length.
The light from the laser bounces back and forth between mirrors on each end of the L, and scientists measure the length of both arms using the light.
If there's a disturbance in space-time, such as a gravitational wave, the time the light takes to
