Violent collision of two black holes detected by astronomers

Scientists have published results showing that they have detected a collision between two black holes that resulted in the largest “bang” since the original Big Bang.

Researchers believe that a massive gravitational wave detected on May 21, 2019 was from the violent collision of two small black holes that collided about 7 billion years ago, when the universe was about half its current age. The collision was only detected last year because it is incredibly far away.

The signal, labeled GW190521, was detected by both the National Science Foundation’s Laser Interferometer Gravitational-Wave Observatory in the US and by the Virgo interferometer in Italy, according to MIT News.

Because the detectors allow scientists to pick up the gravitational waves as audio signals, scientists actually heard the collision. For all the violence and drama, the signal lasted only one-tenth of a second.

“It just sounds like a thud. It really doesn’t sound like much on a speaker,” said California Institute of Technology physicist Alan Weinstein, who was part of the discovery team.

Scientists say the result of the black holes colliding created the first-ever observed intermediate black hole, at 142 times the mass of the sun.

Before this discovery, astronomers only had observed black holes in two general sizes. There are “small” ones called stellar black holes that are formed when a star collapses and are about the size of small cities. And there are supermassive black holes that are millions, maybe billions, of times more massive than our sun, around which entire galaxies revolve.

Black hole collisions have been observed before, but the black holes involved in this collision were smaller to begin with. Even after the merger didn’t grow beyond the size of typical stellar black holes.

The Associated Press contributed to this story.