Created by the collusion of two smaller black holes, the first intermediate black hole has been discovered by astronomers, who actually were able to “hear” the collision taking place, NBC News reports.

Black holes have been found in two sizes:  “stellar” black holes, which are formed by the collapse of stars that are 50- to 100-times larger than our Sun, resulting in a black hole the size of a small city but typically no more than 70-times the mass of our Sun; and “supermassive” black holes that are so large galaxies spin around them.

This intermediate black hole was found when astronomers heard the signals from two separate black holes, one 66-times the Sun’s mass and the other 85-times the Sun’s mass.  Converting the massive gravitational wave created by the collision of these two objects into audio signals, the scientists were able to hear the literal “crash” of these two black holes that resulted into an “intermediate” sized black hole around 140-times the mass of the Sun. 

“It just sounds like a thud,” said Caltech physicist Alan Weinstein. “It really doesn’t sound like much on a speaker.”  The sound lasted approximately one-tenth of a second as the gravitational wave passed Earth at close to the speed of light.

Scientists don’t know if the supermassive black holes at the center of galaxies formed by the combination of several smaller black holes, or if they are a byproduct of the Big Bang, which formed our universe.