Cosmic Crash: The researchers found the largest known collision of two black holes. They found evidence of these and other collisions of black holes in the data of the Ligo and Virgo scientific instruments.
Four new collisions have been discovered by scientists of the two observatories, which detect gravitational waves. The data come from the second analysis of the Gravitational-Wave Observatory (Ligo) advanced laser intervalometer, which took place from 30 November 2016 to 25 August 2017. Up to now, ten such collisions are known. The new researchers announced at a conference these days.
Collisions were recorded in July and August last year. The first event was also the most spectacular: two black holes crashed in one another and merged into one. Almost five solar masses have been converted into gravitational waves.
Collision five billion years ago
The GW170729 is therefore the most massive source of gravitational waves ever seen – and further away: it took about five billion years for gravitational waves to move at the speed of light until they reached Earth. This means that the collision occurred about 400 million years before the birth of our solar system.
One of the other events of 18 August 2017 included both the two detectors of the US Ligo observatory and the Italian-French gravitational wave detector Virgo at Cascina in Italy. This made it possible to locate the source in the northern sky relatively well.
In the spring of 2019 it is again observed
"Modeling of state-of-the-art waveforms, advanced data processing and improved instrument calibration enabled us to more accurately determine the astrophysical properties of previously announced events"says Alessandra Buonanno, director of the Max Planck Institute for Gravitational Physics in Potsdam. The next observation run is scheduled for the spring of 2019. Until then, both observers should be improved. The researchers hope to find on average two signs of melting black holes a month.
Gravitational waves are therefore disturbances of space-time. Albert Einstein predicted gravitational waves in his general theory of relativity. Only in 2016 could they be experimentally detected. The following year the three explorers received the Nobel Prize in Physics.