Timeline

Take a tour of the history of LIGO and VIRGO through the gravitational wave events they have detected.

This kind of skymap is called a Mollweide map and works exactly like maps of the globe, where the spherical Earth is represented as an oval. The brightness of each pixel represents the likelihood that the gravitational wave originated from that location in the sky, the bar at the bottom shows the probability gradient and the highest probability pixel value.

At 9:50am (UTC) on the 14th of August 2015, LIGO announced the first confident detection of a gravitational wave. The wave was created by a binary black hole merger with corresponding masses of around 37 and 31 times the mass of our sun (a quantity abbreviated to Msun). The resultant black hole has a mass of around 63 Msun, meaning about 5 Msun was released as energy in the form of gravitational waves

The second black hole merger detected by LIGO, with black holes of masses 14 and 8 Msun. The final mass of the black hole was around 20 Msun and so about 2 Msun was released as energy.

For the first time, both LIGO and VIRGO detect the same gravitational wave. Caused by a binary black hole merger of masses around 31 and 25 Msun. The resultant black hole has a mass of around 53 Msun and about 3 Msun was released as energy

The first instance of LIGO and VIRGO detecting gravitational waves from colliding neutron stars, with masses around 1.5 and 1.2 Msun. This was the first ever event to be detected with both gravitational waves and light.

On the 14th August 2019 LIGO and VIRGO announced their latest discovery, a binary merger between a black hole of around 23 Msun and a smaller companion of mass 2.3 Msun. However, scientists were not sure whether the companion was either the heaviest known neutron star, or the lightest black hole. This ‘mass mystery’ has still not been solved

These were just some of the 90 (as of 13/09/2022) detected gravitational waves during the three observing runs. The next run, O4, is planned to begin in March of 2023, where LIGO and VIRGO will be joined by KAGRA in Japan and the run will last one year. O5 is planned to begin sometime after 2026.

ESA and NASA’s plans to launch LISA (a space-based interferometer) are going ahead after the success of the LISA Pathfinder mission in 2015. LISA hopes to be launched in the 2030s

Essentially, we’re just getting started exploring the Universe through the lens of gravitational waves. Over the next few years there are many exciting missions and observations to come, with the possibility of brand-new discoveries in this revolutionary field.

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Or to see a full timeline of LIGO click here