For years, black holes were invisible to humans, only theorized but never seen.
Only a short while ago though, the first-ever image of a black hole was revealed to the world. Now, in a turn not many were expecting, we can hear a black hole too.
A team of astrophysicists converted the X-ray echoes of eight black hole binaries found in the Milky Way into sound waves, producing eerie results.
Using a new tool called the "Reverberation Machine," the researchers pinpointed the black hole echoes in data from NICER, a telescope aboard the International Space Station. They then turned them into sound waves, which you can listen to in the video below.
The scientists, who published their findings in The Astrophysical Journal, describe eight new black hole X-ray binaries and their resulting echoes.
These are produced when a black hole is orbiting and "feeding" on a large companion star, releasing an abundance of X-rays in the process. This allows astronomers to observe distant black holes that would otherwise be invisible. Some of these X-rays reflect off of the black holes' accretion disc, emitting the "echoes" picked up by the team of scientists.
Uncovering the role of black holes in galaxy evolution
The astrophysicists collected their data to learn about the evolution of black holes as they feed on nearby stars. "The role of black holes in galaxy evolution is an outstanding question in modern astrophysics," MIT astrophysicist Erin Kara, a co-author of the study, explained in a press release.
"Interestingly, these black hole binaries appear to be 'mini' supermassive black holes," Kara continued, "and so by understanding the outbursts in these small, nearby systems, we can understand how similar outbursts in supermassive black holes affect the galaxies in which they reside."
As a side project to her team's research into black holes, Kara is working with MIT education and music scholars to convert the emission from a black hole X-ray echo into audible sound waves. The lower frequency light was converted to lower pitches and the high-frequency light to higher pitches. The results, in the video above, give a satisfyingly eerie effect that would feel right at home in any sci-fi horror movie.