BENGALURU: Scientists, including Indians working with the Laser Interferometer Gravitational-wave Observatory (LIGO), said that they successfully detected the fourth gravitational wave, ripples in space and time, from the merger of two massive black holes, yesterday. It’s the fourth time this phenomenon has been measured by the scientists at LIGO. The same group made history by detecting the first wave signals early last year. While such detections seem to be routine now, this latest discovery is unique since it was also picked up by a separate European non-LIGO observatory, Virgo.
The scientists said that this has significantly contributed to the improved localization of the astronomical source in the sky, and enabled new tests of Albert Einstein’s theory based on the polarization of gravitational waves. Until the first detection of gravitational waves by the LIGO team in 2015, they existed only in Einstein’s theory.
“The Virgo detector started collecting data on August 1 2017, and was soon bestowed with a detection, jointly with LIGO. The signal was produced by the merger of two massive black holes, weighing 31 and 25 times the mass of the Sun at a distance of 1.7 billion light years away from us. An energy equivalent to the mass of three Suns was radiated as gravitational waves in this energetic astronomical event,” the scientists said.
Results from the latest detection have been accepted for publication in the journal Physical Review Letters. The LIGO-Virgo collaboration includes more than a thousand scientists from many different countries, setting a great example in international scientific cooperation. The recent publication has 40 authors from 13 Indian institutions.
“The Indian team has made contributions to the extraction of the properties of the astronomical source from the data and to the first tests of Einstein’s theory using these observations. The Indian contribution to this emerging frontier will grow significantly in the future, with the materialisation of the LIGO-India observatory, which is being built on Indian soil. This is expected to bring manyfold improvements to the source localisation accuracy” read a LIGO statement.
(Edited and compiled by Santadeep Dey, Team Swalla)