For the first time in history, earthlings can hear what a black hole sounds like: a low-pitched groaning, as if a very creaky heavy door was being opened again and again.

NASA released a 35-second audio clip of the sound earlier this month using electromagnetic data picked from the Perseus Galaxy Cluster, some 240 million light-years away.

The data had been sitting around since it was gathered nearly 20 years ago by the Chandra X-Ray Observatory. The decision to turn it into sound came only recently, as part of NASA's effort over the past two years to translate its stunning space photography into something that could be appreciated by the ear.

"I started out the first 10 years of my career really paying attention to only the visual, and just realized that I had done a complete disservice to people who were either not visual learners or for people who are blind or low-vision," NASA visual scientist Kimberly Arcand told NPR in an interview with Weekend Edition.

While the Perseus audio tries to replicate what a black hole actually sounds like, Arcand's other "sonifications" are more or less creative renditions of images. In those imaginative interpretations, each type of material — gaseous cloud or star — gets a different sound; elements near the top of images sound higher in tone; brighter spots are louder.

For more examples of NASA's sonifications, go to the agency's Universe of Sound web page. Or read on to learn more from Arcand about the venture.

Interview Highlights

On how the black hole audio was made

What we're listening to is essentially a re-sonification, so a data sonification of an actual sound wave in this cluster of galaxies where there is this supermassive black hole at the core that's sort of burping and sending out all of these waves, if you will. And the scientists who originally studied the data were able to find out what the note is. And it was essentially a B-flat about 57 octaves below middle C. So we've taken that sound that the universe was singing and then just brought it back up into the range of human hearing — because we certainly can't hear 57 octaves below middle C.

On sonifying an image of the center of the Milky Way Galaxy

So, we actually take the data and we extrapolate the information that we need. We really pay attention to the scientific story to make sure that conversion from light into sound is something that will make sense for people, particularly for people who are blind or low vision. So our Milky Way galaxy — that inner region — that is this really sort of energetic area where there's just a whole lot of frenetic activity taking place. But if we're looking at a different galaxy that perhaps is a little bit more calm, a little bit more restive at its core it could sound completely different.

­­­­­­­­­­­­On the sonification of the "Pillars of Creation" photograph from the Eagle Nebula in the Serpens constellation:

This is like a baby stellar nursery. These tall columns of gas and dust where stars are forming and you're listening to the interplay between the X-ray information and the optical information and it's really trying to give you a bit of the text.

These soundscapes that are being created can really bring a bit of emotion to data that could seem pretty esoteric and abstract otherwise.