NASA spacecraft deliver stunning visual imagery of the cosmos, but we can also experience that data by turning it into sound. Kim Arcand at the Chandra X-Ray Observatory has helped develop many different sonifications including from galaxies, black holes, nebulae and more. Kim chats with NASA’s Chief Scientist Jim Green about her process of choosing instruments to represent different kinds of light, and plays a few examples of these cosmic sounds. Check out the full series of sonifications atchandra.si.edu/sound.
Jim Green:From Earth, when we look into the sky, we use our eyes. But can we use our ears?
Jim Green:Hi, I’m Jim Green. And this is a new season of Gravity Assist. We’re going to explore the inside workings of NASA in making these fabulous missions happen.
Jim Green:I’m here with Kim Arcand, and she is a visualization scientist and a science communicator for NASA’s Chandra X-Ray Observatory. She’s based at the Harvard Smithsonian Center for Astrophysics in Boston, and has been working on turning satellite data all across the universe into spectacular images and sounds. Welcome, Kim, to Gravity Assist.
Kim Arcand: Hi, thanks so much for having me today.
Jim Green: Well, it’s really a pleasure because this sonification idea is really nifty. How we can use our senses to really understand data and looking at it in a different way.
Jim Green: Kim, can you tell us a little bit more about Chandra and what it’s been looking at?
Kim Arcand:Yeah, so Chandra was launched back in July of 1999, and has kind of been NASA’s flagship mission for X-ray astronomy. Chandra gets to look at amazing things like exploding stars, areas around black holes and some of the largest gravitationally bound objects in the universe or galaxy clusters. But it also gets to look at other things too, like nearby and our solar system. It looks at planets and comets and lots of things. So it’s all about being able to understand those high-energy processes and just figure out so many different answers to the questions that X-ray astronomers have had for quite a few years.
Jim Green: You know, I just recently went to the dentist and I had my mouth X-rayed. Is that the same kind of frequency and it as Chandra does, when it looks into the sky?
Kim Arcand: It’s related. So you, when you go to the dentist, there is a machine that’s pointing at your mouth, and it’s directing X-rays to you, Chandra is not a machine that’s pointing X-rays out into the universe, but rather, it’s a series of detectors and other kinds of equipment that is capturing that X-ray information that is coming to us — traveling, if you will, across the universe from these various cosmic sources, whether it’s a star that’s exploded, or whether it’s a neutron star, or whether it’s something else entirely.
Kim Arcand:We have all of these different kinds of light from radio waves, and microwaves up to x-rays, and gamma rays. And for astronomers, all of those different kinds of light, they’re like a different kind of tool that they can pluck out of their toolbox to be able to ask a question and try to figure something out, or try to get you know, more information on something. And so it really is important today, I feel like the, the modern astronomers’ strength is being able to have all of these different kinds of light at their disposal. And you can kind of think of it like, if you are at all musical, and you could say, play the piano, which disclaimer, I cannot play the piano. But just as an analogy, if you sat down and you found middle C, and you played that, and then you played a couple keys on either side, that amount of sound would be equivalent to optical light. So you would have all the rest of the keys, all the rest of those 88 keys on the keyboard that you wouldn’t be hearing if you were only paying attention to that optical information. So by listening and understanding the microwaves, ultraviolet light, the gamma rays, what have you, you’re able to hear all of those keys on your keyboard, essentially, and you’re going to get a much richer set of information.
Jim Green:Okay, well, you’ve led the development of some really cool techniques like data sonification, which we’re going to talk about in a minute, but tell us in general, how do you approach this challenge of turning satellite data into sounds?
Kim Arcand: For us data sonification really is a way of taking information that for the most part, humans can’t see, right? If you’re working with X-ray light, no human naturally can see X-rays. If you’re working with infrared light or ultraviolet and even in the optical, many times our human eyes are not not strong enough or sensitive enough to be able to pick up all that emission anyway. So that’s why we have these telescopes people to do that really hard work for us. So it’s all about translating something you can’t see into something you can experience. And astronomy has sort of prioritized visuals for a long time. But there’s no reason why you can’t include other senses as well in that bigger sort of storytelling product. So you can use sound, you can even use haptic or vibrational information.
Jim Green: Well, let’s really get into it, I want to hear what you’re talking about. You know, now some of our listeners will be familiar with the spectacular image called the Pillars of Creation that Hubble Space Telescope initially made just so beautiful. And what exactly is the Pillars of Creation, and let’s talk about that before we listen to it.
Kim Arcand: Sure. So the Pillars of Creation is just this beautiful, iconic clump of data that the Hubble originally released back in 1995, I believe, and other observatories have been looking at it ever since. It’s this beautiful stellar nursery, where stars are being born. And so if you’re looking at that in optical light, you’re seeing these tall pillars of gas and dust. And there’s three main pillars, and they’re sort of offset from each other in space. But if you’re looking at the same patch of sky in X-ray light, you’re instead seeing hundreds, if not thousands, and a broader field of view of these more compact sources. And those are essentially very, very young stars or stars that are in the process of forming what are called protostars. So you’re getting all of the little tiny bits of high-energy light from those baby stars in progress. So when you combine the two different kinds of light, the X-ray and the optical, you get a really rich sense of the pillars themselves, where stars are forming, and then the wider area around it where all of these other stars are being detected in X-ray light that are in the process of developing. And so you can take that information from the data and then translate it into sound.
Jim Green:All right, well, let’s listen to the Pillars of Creation.
Jim Green:Wow, that sounds neat! So how did you go about translating a beautiful image with the stars are forming, eating up gas, blowing away the rest creating these pillars? And how did you get that into that sound?
Kim Arcand: Well, so what we did is we sort of take that image and and map it, right, so you’re, in this case, you’re moving across the image horizontally from left to right. And both of the sounds that you’re hearing, you’re hearing both optical and X-ray light represented as different kinds of sounds, right. So in this case, there’s like this continuous range of pitches. And for the optical data, it’s so very, sort of, structured. So that sort of, like sweeping sound that you’re hearing is really trying to depict the shape of those pillars. And then that higher pitch sound that you’re hearing — those, sort of, bright sources that you’re hearing — that is the young stars that we’re detecting, in X-ray light.
Jim Green: Well, another really great one that you recently released was the Chandra Deep Field South. What was your approach in turning that into sound and let’s listen to it.
Kim Arcand: So that’s very different, I think than the last one.
Jim Green:It is! It is!
Kim Arcand:…that we heard. And what’s nice about this is it’s a very, very different object, if you will, so the Pillars of Creation, those are relatively nearby. It’s what perhaps 5,000 light-years away from Earth. The Chandra Deep Field South is incredibly distant. It’s the deepest X-ray image we’ve ever obtained. And it’s like 11, 12 and 13 billion light-years away the various objects in that field. So it’s a very different type of data to approach. And so we used a very different technique. And in this case, because it was such a busy field of view of all of these little dots, which are essentially black holes, or galaxies, what we wanted to do is approach it from the bottom up so that you could have a stereo sound. And each of those dots then the color represents the different X ray energies or with the lower notes, for example, representing the lowest energy X-rays and the highest notes representing the highest energy X-rays. So as you’re sort of scooting up through that data set, you can hear all of the different kinds of sources, all of those different black holes, hundreds and hundreds of black holes as you’re going through the entire field of the Chandra Deep Field South.
Jim Green: Well, another really great one is the Crab Nebula, you know, that’s a cosmic object that we’ve studied for, you know, centuries, you know, because it originally started in 1054, with a massive explosion.
Kim Arcand: Yeah, it’s a, it’s a great object. It’s very famous, it’s relatively nearby, it’s perhaps 6,000 light years away in the Milky Way. It’s in a great location for us to be able to view and many, many, many different telescopes, observatories have been used to capture fantastic information of that object over time. So the Chandra X-ray observatory has been looking at, looking at that object pretty much since it was launched back in 1999. And the Hubble Space Telescope and the Spitzer Space Telescope have looked at it many times as well. So this data set is a collection of those three different kinds of light, the X-ray light from Chandra, the infrared light from Spitzer, and the optical light from Hubble. And when you’re looking at the data set, it’s this very dramatic, sort of wispy looking thing. It’s got all of these rings and a jet, and then all of this massive, nebulous stuff all around it. And so you’re looking at the leftovers of that stellar explosion. You’ve got the spinning neutron star, the pulsar at the very center, and that’s the brightest, most energetic region, you’ve got all of the rings and the jets that are coming out of it. And then you’ve got the cooler gas and dust that are in the infrared and optical data all around the perimeter.
Jim Green: Well, let’s listen.
Kim Arcand:So for this piece, we wanted to be able to hear those individual things, right. So the X-rays from Chandra are like, a harsh breath sound. And the optical light from the Hubble Space Telescope would be like the lighter strings, and the infrared data from Spitzer, which is the lowest energy material that is like soft woodwinds type of sound. So again, you have to think of it as sort of like a map. And so in this case, the, the light that we’re seeing towards the top of the image is being played as higher pitch notes. And the brighter light overall is being played louder. So there’s a lot going on.
Jim Green: Wow, I think that is my favorite at the moment. But let’s do another one. Let’s listen to your rendition of the center of our galaxy, the Milky Way. And then tell us how you put that together.
Kim Arcand:This one might be my favorite, though, it’s really hard to pick, just because it was one of the first ones that we worked on.
Kim Arcand:But for the galactic center, this is a very classic image. It’s of course, our home galaxy. We’re looking at the inner about 400 lightyear region around the supermassive black hole Sagittarius A star at the very core of the Milky Way. And again, we have incredible bits of information from various NASA observatories, we’ve got the X-ray light from Chandra, of course, we also have the infrared light from Spitzer and additional information from the Hubble Space Telescope. And they look very different when you’re looking at these different kinds of light.
Kim Arcand:And particularly as you approach the supermassive black hole, as you skew across the image from left to right, you’ll hear there’s this massive crescendo, and it’s where all the sort of action is happening. So again, just sound-wise, what you’re listening for, the infrared is going to be played as a soft piano, the optical or the mid-range will be played as a plucky violin. And then the highest energy X-rays will be this really high-noted xylophone sound.
Kim Arcand:And I should say, none of this would have been possible without the incredible diligence and talented work of the colleagues that I’ve been working with this for this entire project on and they’re from System Sound. Matt Russo’s an astrophysicist and musician and Andrew Santaguida is a sound engineer and it really is a major group effort. There’s really no “me” in science, it’s all “we,” so just, just wanted to bring them into the story because I feel like they’ve just been incredibly talented and how they approach this.
Jim Green:But you know, besides all your work in sonification, and data visualization, I know you’ve been very active in public outreach, especially trying to get our young people interested in astronomy. So can you give me a little insight as to what you’ve been doing in that area recently?
Kim Arcand: Yeah, it really is a complete joy to be able to do this type of work, I just love it. Like, I really, really love it. My sort of areas of expertise tend to be in things like helping other people to be able to experience the universe. So a lot of the work we’ve done at Chandra has been taking objects and modeling them into 3-D so that we can 3-D print them, bring them into virtual reality, or holograms, or augmented reality. And that project, I think, really sort of opened up my eyes as to just the many different ways that we can all experience the universe. For someone who is either blind or visually impaired, being able to access 3d printed model or the data sonification provides a really rich experience. And so with these types of projects, we work with people, either astrophysicists or amateur astronomers or other students, for example, who are blind or visually impaired in order to really improve the product and make it something that the community is going to be able to appreciate.
Jim Green: Yeah, sounds fantastic. Well, you know, Kim, I always like to ask my guests to tell me what that event, person place or thing that got them so excited about becoming the scientists they are today. And I call that event a gravity assist. So Kim, what was your gravity assist?
Kim Arcand:You know, I’m not sure if it was someone who helped me realize that science would be for me, or it’s just somebody who helped me realize that there are different ways of experiencing things. I was a super, super shy kid, like, you know, hide behind my mom type of shy kid when I was little. And I didn’t make friends easily. I was just so shy. And so when I went to kindergarten, I remember being like really anxious. And I had a hard time making friends. But my very first friends is this little girl. She was deaf, and she actually helped teach me sign language so I could communicate with her and she had an assistant teacher who also helped us.
Kim Arcand:And I think that experience never left me. I think I always just sort of realized from day one, like, how important is it is for other people to bring you into their worlds and vice versa. And so I think that’s kind of. that was kind of like a first step for me. It took many, many years before ended up doing work at all related to those types of experiences. But I think it was just a key moment that stuck with me my whole life of being able to appreciate other people’s perspectives. And the kindness that she offered me as someone who didn’t friends easily was definitely something that I appreciate. And I wish I remember, like her name, and I could find her again, because I will actually love to say thank you to her. But yeah, I’ll have to give her credit for “gravity assist.”
Jim Green:Well, I know being shy, you really have to work on being able to project and talk about your ideas and everything. And I think you’ve been doing a fantastic job, allowing us to listen to data in new and unique ways. So Kim, thanks so much for joining me and discussing this fascinating topic.
Kim Arcand:Thank you so much. This was really fun.
Jim Green: Well, join me next time as we continue our journey to look under the hood at NASA, and see how we do what we do. I’m Jim Green, and this is your Gravity Assist.
Credits
Lead producer: Elizabeth Landau
Audio engineer: Manny Cooper
Video producers:Elizabeth Landau and Lacey Young