SSC CHSL 17 Mar 2020 Shift 3 Paper

LIGO (Laser Interferometer Gravitational-Wave Observatory) was used to detect gravitational waves for the very first time. LIGO use mirrors spaced $4\mathrm{km}$ apart which are capable of detecting a change of less than one ten-thousandth the charge diameter of a proton.
The detection of gravitational waves was reported in 2016 by the LIGO Scientific Collaboration (LSC)and the Virgo Collaboration with the international participation of scientists from several universities and research institutions.