Something About LIGO(Laser Interferometer Gravitational Wave Observatory)

LIGO is the world's largest gravitational wave observatory. It consists of two detectors.  Each L-shaped facility has two arms positioned at right angles to each other . Lasers are beamed down each arm and bounced back by mirrors, essentially acting as a ruler for the arm. Sensitive detectors can tell if the length of the arms of a LIGO detector varies by as little as 1/10,000 the width of a proton, representing the incredibly small scale of the effects imparted by passing gravitational waves. LIGO has two observatories to act as a check on the other to rule out that a potential gravitational-wave signal detection is not due to a local, terrestrial disturbance; both facilities will detect a true gravitational wave moving at the speed of light nearly simultaneously. Although the twin LIGO facilities act as a single observatory, they are not designed for "observing" in the conventional sense. Instead of eyes, the facilities can be thought more of as "ears" listening for gravitational waves, or even as a skin trying to "feel" the slightest of movements.

Within LIGO, the lasers beamed down its arms bounce back and are set to cancel each other out completely. As a result, no light reaches another LIGO component called a photodetector. If, however, a gravitational wave were to pass through the LIGO facility, it would stretch one detector arm and compress the other, throwing off this perfect destructive interference. Some light would then reach the photodetector. The pattern of this light would provide information about the changes the arms underwent, and thus reveal properties about the incident gravitational waves and their source.

This observatory was so huge and big enough to detect Gravitational waves for first time as per Albert Einstein's predictions of Gravitational waves and space time fabric.

In 2017 this project got Nobel prize in physics for detecting gravitational waves.