LIGO
The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a large-scale physics observatory which detects cosmic gravitational waves co-founded by Scottish physicist Ronald Drever.[1] They were first funded by the National Science Foundation (NSF) and were conceived, built and are operated by Caltech and MIT.[2][3] The NSF has funded improvements for LIGO to increase sensitivity, which allowed them to make the first detection of gravitational waves.[4][5] LIGO is the largest and most ambitious project ever funded by the NSF.[6][7]
LIGO is an interferometer. It fires a laser beam and splits it into two laser beams. Mirrors bounce them back towards a light detector and merge them. Normally, the two laser beams should cancel each other, so the light does not reach the detector, but any changes in space-time caused by gravity waves can change the laser beams, so that they don't cancel out fully. When this happens, the light detector will see some of the laser light, which it can then use to work out the size of the space-time distortion.[8]
LIGO Media
Aerial views of LIGO Hanford Observatory
LIGO Laboratory operates two detector sites, one near Hanford in eastern Washington, and another near Livingston, Louisiana. This photo shows the Livingston detector site.
Detector noise curves for Initial and Advanced LIGO as a function of frequency. They lie above the bands for space-borne detectors like the evolved Laser Interferometer Space Antenna (eLISA) and pulsar timing arrays such as the European Pulsar Timing Array (EPTA).
Western leg of LIGO interferometer on Hanford Reservation
Northern leg (x-arm) of LIGO interferometer on Hanford Reservation
Simplified diagram of an Advanced LIGO detector (not to scale).
Design sensitivity of Advanced LIGO interferometer with major noise sources, maximum sensitivity is around 500 Hz
References
- ↑ Barish, Barry C.; Weiss, Rainer (October 1999). "LIGO and the Detection of Gravitational Waves". Physics Today. 52 (10): 44. Bibcode:1999PhT....52j..44B. doi:10.1063/1.882861.
- ↑ "LIGO Lab Caltech MIT". Retrieved 24 June 2016.
- ↑ "LIGO MIT". Retrieved 24 June 2016.
- ↑ "Revolutionary Grassroots Astrophysics Project "Einstein@Home" Goes Live". Retrieved 3 March 2016.
- ↑ "LSC/Virgo Census". myLIGO. Retrieved 28 November 2015.
- ↑ Larger physics projects in the United States, such as Fermilab, have traditionally been funded by the Department of Energy.
- ↑ "LIGO Fact Sheet at NSF". Archived from the original on 2011-10-31. Retrieved 2016-10-07.
- ↑ (in en) Physicists win Nobel Prize for spotting ripples in fabric of space-time. https://www.theregister.co.uk/2017/10/03/gravitational_wave_detection_wins_nobel_prize_for_physics/. Retrieved 2018-09-06.