LIGO (Laser Interferometer Gravitational-Wave Observatory) and Virgo are advanced scientific observatories designed to detect gravitational waves—tiny ripples in spacetime caused by massive cosmic events like colliding black holes, neutron star mergers, or supernovae.
Gravitational waves were predicted by Albert Einstein in 1916 as part of general relativity, but remained undetected for a century due to their incredibly small effects. That changed in 2015, when LIGO made the first-ever direct observation of gravitational waves from a pair of merging black holes—a groundbreaking discovery that confirmed a major prediction of relativity and earned the 2017 Nobel Prize in Physics.
LIGO (located in the United States) and Virgo (in Italy) use laser interferometry to detect the minuscule stretching and squeezing of space caused by passing gravitational waves—changes far smaller than the width of a proton. By working together, these detectors can triangulate the source of the waves and help astronomers study the universe in an entirely new way: through gravitational wave astronomy.