Earlier this week, NASA scientists tweeted out sound made by the black hole at the center of the Perseus galaxy cluster roughly 240 million lightyears away.
The sound, which has been described as eerie and even haunting, is created through a process called “sonification” – in this case turning X-ray satellite data into audio.
Rafael Lang is a professor of physics and astronomy at Purdue University. He said the actual sound emitted by the black hole is far too low for the human ear to be able to hear.
“The sound is not audible to your ears,” he said. “It is shifted by millions and millions and millions of factors to completely very low frequencies.”
The misconception that there is no sound in space originates because most space is a ~vacuum, providing no way for sound waves to travel. A galaxy cluster has so much gas that we've picked up actual sound. Here it's amplified, and mixed with other data, to hear a black hole! pic.twitter.com/RobcZs7F9e— NASA Exoplanets (@NASAExoplanets) August 21, 2022
According to reporting from the Washington Post, the sound waves were initially discovered in 2003. NASA experts more recently converted the sound into a frequency that could be heard by the human ear for release to the general public.
But the audio isn’t exactly the sound a black hole makes - it’s a representation.
Lang said the audio is one answer to a question scientists are always asking about the universe.
“How do we make the universe and what is going on in the universe accessible to our senses? We need tools, we need machines, we need telescopes,” he said. “But even then the data coming off of then is just ones and zeroes. We need to explore different ways of making sense of that… for that the sonification that they have chosen can be quite useful.”
For Lang, who studies dark matter, it’s a question he thinks about a lot.
“There’s five times more stuff in the universe than anything we know about and we have no frickin’ clue what that stuff is,” he said. “...The point being, it is my job to think about what else might be in the universe that we haven’t been able to make accessible to our senses.”
Lang said NASA scientists modified the frequency so that the general public could experience the sound of a black hole – and understand a little bit more about the universe.
“It is always useful and helpful to look at the same piece of information in different ways and see which way strikes a chord and where you make connections you haven’t made previously,” he said. “That’s where this kind of sonification can be quite useful.”