SCOTT SIMON, HOST:
NASA has been capturing awesome - and for once the word is justified - images from outer space for more than 60 years, the blue marble of Earth, the auroras of Jupiter, the Andromeda Galaxy, millions of light-years away. But what does outer space sound like? Maybe this.
(SOUNDBITE OF MUSIC)
SIMON: That's what NASA calls a sonification - not the literal sounds from the cosmos, but a translation to help blind and low-vision people appreciate the majesty of space. It's a project that Dr. Kim Arcand has been working on at NASA's Chandra X-ray Observatory. She joins us now.
Dr. Arcand, thanks so much for being with us.
KIM ARCAND: Hi. Thanks so much for having me.
SIMON: That was a clip that purports to sound like the Milky Way Galaxy, right?
ARCAND: Right. Exactly. That is, like, the inner 400 light-years around our Milky Way's sort of downtown area. So what we're doing is we're actually taking light and translating it into sound as a way to make our data a little bit more approachable.
SIMON: How does that work?
ARCAND: 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.
SIMON: So they would hear the differences between different galaxies.
ARCAND: Right, exactly. So our Milky Way galaxy - that inner region that we just heard - 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.
SIMON: You're a visual scientist, I gather. What moved you to accomplish this in sounds?
ARCAND: Actually, I think I started out the first, like, say, 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. And so during the pandemic, particularly, I reached out to some colleagues who specialize in this sort of area of data sonification, Matt Russo and Andrew Santaguida, to be able to work with them to take data from NASA's Chandra X-ray Observatory and the Hubble Space Telescope and translate it into a way that could be heard in a really exciting new form.
SIMON: Well, I can't wait to hear another example. This is, I'm told, "Pillars Of Creation."
(SOUNDBITE OF MUSIC)
SIMON: Oh, my gosh.
SIMON: That really reaches inside, doesn't it?
ARCAND: I hope so. I think those soundscapes that are being created can really bring a bit of emotion to data that could seem pretty esoteric and abstract otherwise. In what we just heard, we're listening now to, like, a baby stellar nursery, so 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.
SIMON: Wow. Now, I'm told that earlier this month, you and your team developed not just a sonic representation of an image, but - get ready for this, everyone - the actual sound of a black hole.
(SOUNDBITE OF BLACK HOLE)
SIMON: Please, Dr. Arcand, forgive me for this. I'm dazzled. But am I just going to hear this in a "Star Wars" film?
ARCAND: (Laughter) So for some reason, most of the people who have heard this have responded it either sounds like a horror movie soundtrack or something from a Hans Zimmer score. But yeah, 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.
SIMON: Oh, my word. Does our Earth send out a sound? And I hope it's not by B. J. Leiderman, who does our theme music. But please go ahead.
ARCAND: There are sounds for sure that we are making as humans on Earth. However, what's interesting about sonifications like this of Perseus that are far, far away is that there is actually a medium for those sound waves to travel through, whereas here in the solar system, we don't have that medium. So in this cluster of galaxies, there's this hot gas, and that pressure wave is moving through them. And that's how the sound waves are being formed.
SIMON: I'm just stupefied, I've got to tell you.
ARCAND: That's great, I guess (laughter).
SIMON: Dr. Kim Arcand is a visualization scientist at NASA's Chandra X-ray Observatory and the Harvard-Smithsonian Center for Astrophysics. And by the way, you can find some of these sonifications at our website, npr.org.
Thank you so much, and keep listening to the stars.
ARCAND: Thanks so much.
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