About seven billion years ago, two black holes spiraled into each other to form a massive black hole, GW190521. The black hole, which is one of the oldest and most massive black holes ever detected, has a mass that is 142 times that of the sun.
The collision of the black holes had generated ripples called gravitational waves that were picked up by the gravitational wave observatory – the Laser Interferometer Gravitational-Wave Observatory (LIGO), United States and the detector Virgo, Italy. However, what is peculiar about this discovery is that until now, a black hole with a mass in an intermediate mass range, that is, between 100 to 1000 times that of the sun had not been found.
Talking about the significance of the discovery, Stavros Katsanevas, co-author and astrophysicist at the European Gravitational Observatory, stated that the discovery opened the doors to a better understanding of the formation of black holes. He called it a “whole new world”.
Christopher Berry, a reviewer of the research, stated that the event has answered one of the great mysteries of the past, whether intermediate black holes exist or not. The discovery will also help scientists understand the origin of supermassive black holes. Berry, in a press release, stated:
The scientists found out that the black hole GW190521 was formed by the merger of two smaller black holes of 85 and 65 solar mass. When these two smaller black holes spiraled into one another, energy worth eight solar masses was released, making it one of the most powerful events in the history of the universe.
Pedro Marronetti, Program Director, National Science Foundation, stated that LIGO has yet again surprised the scientific community by detecting extremely massive black holes. He said that “this is of tremendous importance since it showcases the instrument’s [LIGO’s] ability to detect signals from completely unforeseen astrophysical events. LIGO shows that it can also observe the unexpected.”
The discovery and analysis has been published in two research papers, namely, Physical Review Letters and Astrophysical Journal Letters. It has a detailed report on the discovery, the physical properties of the signal, and an analysis of how the two black holes might have collided billions of years ago.
This is only the beginning of a new era of Astrophysics. It has opened up a plethora of questions for the scientists across the world.