The first detection!

On 14 September 2015, history was made.

For the first time, scientists observed the ripples in the fabric of spacetime called gravitational waves. They arrived at the Earth from a cataclysmic event in the distant universe: The detected gravitational waves were produced during the final fraction of a second of the merger of two black holes to produce a single, more massive spinning black hole. This collision of two black holes had been predicted but never observed.

The gravitational waves were detected on September 14, 2015 at 5:51 a.m. Eastern Daylight Time (09:51 UTC) by both of the twin Laser Interferometer Gravitational-wave Observatory (LIGO) detectors, located in Livingston, Louisiana, and Hanford, Washington, USA.

Based on the observed signals, the scientists of the LIGO Scientific Collaboration estimate that the black holes for this event were about 29 and 36 times the mass of the sun, and the event took place 1.3 billion years ago. About 3 times the mass of the sun was converted into gravitational waves in a fraction of a second—with a peak power output about 50 times that of the whole visible universe. By looking at the time of arrival of the signals—the detector in Livingston recorded the event 7 milliseconds before the detector in Hanford—scientists can say that the source was located in the Southern Hemisphere.

UK collaborators discuss the project for detection of gravitational waves.

Researchers at the Max Planck Institute for Gravitational Physics in Hannover and Potsdam in Germany were the first to see the signal. This movie tells the story of the significant contributions of groups in the UK and Germany to this ground-breaking discovery.

LIGO Detection reveals what unfolded behind the scenes between the detection of merging black holes on 14 September 2015, and five months later when LIGO announced it to the world.

More than 1000 people are working to achieve what Einstein thought impossible: Detection of gravitational waves from cataclysmic events billions of light years away.

A computer simulation shows the collision of two black holes, a tremendously powerful event detected for the first time ever by the Laser Interferometer Gravitational-Wave Observatory, or LIGO. LIGO detected gravitational waves, or ripples in space and time generated as the black holes spiraled in toward each other, collided, and merged. This simulation shows how the merger would appear to our eyes if we could somehow travel in a spaceship for a closer look. It was created by solving equations from Albert Einstein's general theory of relativity using the LIGO data.

This simulation was created by the multi-university SXS (Simulating eXtreme Spacetimes) project. For more information, visit Image credit: SXS

This movie shows the first gravitational-wave signal detected by LIGO on September 14, 2015. This is a numerical simulation of two inspiralling black holes that merge to form a new black hole.

© numerical simulation: S. Ossokine, A. Buonanno (Max Planck Institute for Gravitational Physics), Simulating eXtreme Spacetime project; scientific visualisation: W. Benger (Airborne Hydro Mapping GmbH)

Press conference announcing the first direct detection of gravitational waves – February 11, 2016 (part 1)

Press conference announcing the first direct detection of gravitational waves – February 11, 2016 (part 2)