LIGO Detects Gravitational Waves

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The Laser Interferometer Gravitational-wave Observatory (LIGO) has made a third detection of gravitational waves. As was the case with the first two detections, the waves were generated when two black holes collided to form a larger black hole.

The newfound black hole, formed by the merger, has a mass about 49 times that of our sun. This fills in a gap between the masses of the two merged black holes detected previously by LIGO, with solar masses of 62 (first detection) and 21 (second detection).

The new detection occurred during LIGO’s current observing run, which began November 30, 2016, and will continue through the summer. LIGO is an international collaboration with members around the globe.

Its observations are carried out by twin detectors — one in Hanford, Washington, and the other in Livingston, Louisiana — operated by Caltech and MIT with funding from the National Science Foundation (NSF).

LIGO made the first-ever direct observation of gravitational waves in September 2015 during its first observing run since undergoing major upgrades in a program called Advanced LIGO. The second detection was made in December 2015.

The third detection, called GW170104 and made on January 4, 2017.


The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a large-scale physics experiment and observatory to detect cosmic gravitational waves and to develop gravitational-wave observations as an astronomical tool. Two large observatories were built in the United States with the aim of detecting gravitational waves by laser interferometry.

The initial LIGO observatories were funded by the National Science Foundation (NSF) and were conceived, built, and are operated by Caltech and MIT. They collected data from 2002 to 2010 but no gravitational waves were detected.

The Advanced LIGO Project to enhance the original LIGO detectors began in 2008 and continues to be supported by the NSF, with important contributions from the UK Science and Technology Facilities Council, the Max Planck Society of Germany, and the Australian Research Council.

The improved detectors began operation in 2015. 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.

LIGO is the largest and most ambitious project ever funded by the NSF.

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