Brian's Einstein@Home Stuff



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 in the USA (one in Handford, Washington and the other in Livingstone, Louisiana), were built with the aim of detecting gravitational waves by laser interferometry.

These observatories [each] use mirrors spaced four kilometers apart which are capable of detecting a change of less than one ten-thousandth the charge diameter of a proton.

The following graphic [source] illustrates the process:

The initial LIGO observatories 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. The improved detectors began operation in 2015. The detection of gravitational waves was reported in 2016. Scientists involved in the project and the analysis of the data for gravitational-wave astronomy includes more than 1000 scientists worldwide, as well as 440,000 active Einstein@Home users (as of December 2016).

Observations are made in "runs". As of December 2019, LIGO has made 3 runs, and made 50 detections of gravitational waves. Maintenance and upgrades of the detectors are made between runs. The first run, O1, which ran from September 2015 to January 2016, made the first 3 detections, all black hole mergers. The second run, O2, which ran from November 2016 to August 2017, made 8 detections, 7 black hole mergers, and the first neutron star merger. The third run, O3 began on 1 April 2019; it is divided (so far) into O3a, from 1 April to 30 September 2019, and O3b, from 1 November 2019 until it was suspended in March 2020 ...

Einstein@Home volunteers have already discovered about fifty new neutron stars, and hopes to find many more. The long-term goal is to make the first direct detections of gravitational-wave emission from spinning neutron stars. Gravitational waves were predicted by Albert Einstein a century ago, and were directly seen for the first time in 2015. This observation of gravitational waves from a pair of merging black holes opens up a new window on the universe, and ushers in a new era in astronomy. This first direct measurement was made soon after the advanced LIGO instruments came online after an extensive five-year upgrade. These advanced detectors took data between September 2015 and January 2016 and can already "see" three to six times as far as initial LIGO, depending upon the source type. Over the next two years this will increase to a factor of ten or more, increasing the number of potentially-visible gravitational-wave sources by a factor of a thousand!


Back to Main