Gravitational waves and LIGO
Gravitational waves are "waves of spacetime curvature produced by the relative motion of gravitating masses and which propagate away at the speed of light." They were predicted by Albert Einstein's theory of general relativity but were not directly detected until 2015. LIGO, the Laser Interferometer Gravitational-Wave Observatory, is "a large-scale physics experiment and observatory designed to detect cosmic gravitational waves" using laser interferometry to measure incredibly tiny changes in distance. Gravitational waves matter because they "transport energy as gravitational radiation" and allow astronomers to observe cosmic events like black hole mergers that cannot be studied with traditional light-based telescopes. This new form of astronomy complements electromagnetic observations and reveals phenomena in the distant universe previously invisible to us.
Sources
- en.wikipedia.org: “Gravitational waves are waves of spacetime curvature produced by the relative motion of gravitating masses and which propagate away at the speed of light.”
- en.wikipedia.org: “The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a large-scale physics experiment and observatory designed to detect cosmic gravitational waves.”
- en.wikipedia.org: “Gravitational waves transport energy as gravitational radiation, a form of radiant energy similar to electromagnetic radiation.”
- en.wikipedia.org: “The first direct observation of gravitational waves was made in September 2015, when a signal generated by the merger of two black holes was received by the LIGO gravitational wave detectors in Livingston, Louisiana, and in Hanford, Washington.”