Astronomers at the Gravitational Wave Laser Interferometry Observatory (LIGO), in collaboration with the Italian observatory Virgo, have detected gravitational waves for the fourth time. This time stands out against the others because the researchers have been able to determine its origin with more precision.
Albert Einstein predicted gravitational waves in General Relativity Theory. According to the scientist, some large events occurring in the universe, such as supernova explosions or the merging of two black holes, produce perturbations in space-time in the form of undulations that carry information about the movement of the objects of the universe.
In September and December 2015, LIGO detected the phenomenon twice, and confirmed the existence of gravitational waves in February 2016. The third wave was identified in June of this year.
So far, the detections have been carried out from the LIGO Washington and Lousiana observatories, but in this case they have had the collaboration of the Italian observatory Virgo. On August 14 they identified the gravitational waves of this fourth wave, which astronomers say have been generated by the violent melting of two black holes more than 1.8 billion light-years away. The black hole resulting from this fusion has 53 solar masses.
Thanks to the three observation points, this time scientists have more information to determine more precisely the source of gravitational waves, since it facilitates triangulation. Thus, compared to previous waves, they have been able to determine the position 20 times better. “With the joining of Virgo we have entered a new phase of astronomy, called multi-messenger astronomy,” says Bangalore Sathyaprakash, a physicist at LIGO.
Scientists will now work to make their observatories more sensitive, and hope to be back by the fall of 2018. “With further improvements, I think we will begin to detect dozens of these events each year,” says Sathyaprakash.