Ground-based Gravitational Wave Detectors - Current Generation
Gravitational waves are extremely small ripples in the structure of spacetime caused by astrophysical events like supernovae or coalescing massive binaries (neutron stars, black holes). They were predicted by Albert Einstein in 1916, but have not yet been directly observed. Gravitational wave astronomy has the potential to provides a totally new look at the Universe. Gravitational waves, once detected, will give information on supernovae, black holes, pulsars, compact binaries and the cosmic background radiation that cannot be obtained by other means.
Current detectors include:
The British-German GEO 600 project which aims at the direct detection of gravitational waves by means of a laser interferometer of 600m armlength.
The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a facility dedicated to the detection of cosmic gravitational waves and the measurement of these waves for scientific research. It consists of two widely separated installations within the United States, operated in unison as a single observatory. This observatory is available for use by the world scientific community, and is a vital member in a developing global network of gravitational wave observatories. LIGO has the possibility to test several of general relativity's predictions.
Virgo is a 3km detector located in Cascina near Pisa, which commenced science runs in 2007. The frequency range and high sensitivity of Virgo should allow detection of gravitational radiation produced by supernovae and coalescence of binary systems in the milky way and in outer galaxies, for instance from the Virgo cluster.
1 image of Ground-based Gravitational Wave Detectors - Current Generation
Artist's impression of gravitational waves from two orbiting black holes
Credit: K. Thorne (Caltech) and T. Carnahan (NASA GSFC)