The first discovery of a gravitational wave occurred at the Laser Interferometer Gravitational Wave Observatory (LIGO) in 2015. LIGO actually consists of two detectors, one in Hanford, Washington, and...The first discovery of a gravitational wave occurred at the Laser Interferometer Gravitational Wave Observatory (LIGO) in 2015. LIGO actually consists of two detectors, one in Hanford, Washington, and the other in Livingston, Louisiana (see Figure 6.3.1). One of the reasons for having two detectors is because any real gravitational wave would necessarily have to travel though both detectors; if only one detector sees what it thinks is a gravitational wave, then it could just be noise.
