Planetary Radio • Mar 15, 2023

Universal Harmonies: Sonifying images for science and accessibility

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On This Episode

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Kim Arcand

Visualization scientist and emerging tech lead for NASA's Chandra X-ray Observatory

Ambre Bio photo

Ambre Trujillo

Digital Community Manager for The Planetary Society

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Mat Kaplan

Senior Communications Adviser and former Host of Planetary Radio for The Planetary Society

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Bruce Betts

Chief Scientist / LightSail Program Manager for The Planetary Society

Sarah al ahmed headshot

Sarah Al-Ahmed

Planetary Radio Host and Producer for The Planetary Society

Kim Arcand from NASA’s Chandra X-ray Observatory joins Planetary Radio to share her team’s new album “Universal Harmonies.” It’s a beautiful collection of sonified observations taken by the space telescope that aims to make space images more accessible to people with low or no vision. The Planetary Society team celebrates the release of their new member community app and shares an update on the Boeing Starliner. Stick around for a chance to win a vinyl version of “Universal Harmonies” in this week’s space trivia contest.

Universal Harmonies album cover
Universal Harmonies album cover Universal Harmonies (released on Mar 10, 2023) is an album comprised of sonified observations from the Chandra X-ray Observatory. This collection hopes to make space images more accessible to those with vision loss by allowing them to listen to images rather than see them.Image: Chandra Labs
The galactic center
The galactic center A composite image of the center of the Milky Way taken with three space-based telescopes. X-rays detected by the Chandra X-ray Observatory are represented in blue and violet, near-infrared light seen by the Hubble Space Telescope is yellow and infrared light captured by the Spitzer Space Telescope is red. The image covers one-half of a degree in the sky, about the width of the full moon. The bright blob of X-ray light in the picture's center-right is Sagittarius A, which contains a suspected supermassive black hole.Image: X-ray: NASA / CXC / UMass / D. Wang et al.; Optical: NASA / ESA / STScI / D.Wang et al.; Infrared: NASA / JPL-Caltech / SSC / S. Stolovy
Chandra Deep Field South
Chandra Deep Field South This image taken by NASA's Chandra X-Ray Observatory showcases the highest concentration of black holes ever seen, equivalent to 5,000 black holes over the area of the sky covered by the full Moon. It took over 7 million seconds of Chandra observing time to create, and at the time of its release in 2017, it was the deepest X-ray space image ever obtained. The colors in this image represent different levels of X-ray energy detected by Chandra. Here the lowest-energy X-rays are red, the medium band is green, and the highest-energy X-rays observed by Chandra are blue.Image: NASA / CXC / Penn State / B.Luo et al.

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Trivia Contest

This Week’s Question:

Name all the countries whose national flag has some representation of the Southern Cross asterism that is part of the Crux constellation.

This Week’s Prize:

A special edition vinyl LP of “Universal Harmonies.”

To submit your answer:

Complete the contest entry form at or write to us at [email protected] no later than Wednesday, March 22 at 8am Pacific Time. Be sure to include your name and mailing address.

Question from the February 22, 2023 space trivia contest:

How many failed missions were attempted to Mars before Mariner 4 succeeded?


Six missions attempted to go to Mars and failed before Mariner 4 succeeded.

Question from the March 1, 2023 space trivia contest:

What was the largest mass of samples returned by a single robotic sample return mission?


The Chinese National Space Administration’s Chang’e 5 returned the largest mass of samples to Earth of any robotic sample return mission at 1,731 grams (3.8 pounds) of lunar material.

Last week's question:

What science instrument on the Voyager spacecraft has a name whose acronym is also the name of a part of an eye?


To be revealed in next week’s show.


Sarah Al-Ahmed: Making space images more accessible through sonification, this week on Planetary Radio. I'm Sarah Al-Ahmed of The Planetary Society, with more of the human adventure across our solar system and beyond. Space is for everyone, and we all deserve to experience space images. Our guest this week, Kim Arcand, and her colleagues at Chandra Labs have just released an album of sonified data from NASA's Chandra X-Ray Observatory. This collection of audio tracks called Universal Harmonies hopes to make space more accessible to people with low or no vision. The result is a beautiful and thought-provoking album of ambient and sometimes spooky audio. This is also a huge week for us here at The Planetary Society. Our new member community app is now live. Ambre Trujillo joins us to talk about the app's launch, and our upcoming welcome festival on March 18th. Mat Kaplan will give us an update on the Boeing Starliner and we'll close out our show with the night sky and a chance to win a special LP version of Universal Harmonies in this week's space trivia contest. As many of you know, I was out sick last week as I recovered from COVID, but I'm back. I'd like to give a special thanks to Mat Kaplan, the creator and former host of Planetary Radio, who filled in for me while I was away. And thank you so much for all the wonderful get well messages you sent me. I cannot tell you how much I appreciate it. Now it's time for some space news. Solar sailing is on the rise. After the success of The Planetary Society's LightSail 2 Mission, solar sailing is growing in popularity as a method for compelling spacecraft. The latest issue of The Planetary Report, our quarterly magazine explores new and upcoming missions like NASA's Advanced Composite Solar Sail System, or ACS3, and how they'll use sunlight to push the boundaries of space exploration. A little bit of sad news. Japan's new H3 rocket was unfortunately destroyed during its inaugural flight on March 7th. Though the rocket's first stage appeared to be performing well, the second stage failed to ignite. Jackson made the difficult decision to send a destruct command to the rocket at 10:52 local time, citing that there was no possible way of achieving the mission. Space is hard, and we wish the H3 teams luck in their future attempts. Remember back in September 2022 when the Dart spacecraft purposefully crashed into the asteroid Dimorphous? It changed the history of planetary defense. The footage was amazing. We practically punched an asteroid in the face for the dinosaurs, and we should all be proud. Hubble, the Italian Space Agency's LICIACube, and telescopes worldwide spotted the distant space debris after the impact. It was awesome. Now, a new video of Hubble images released by the European Space Agency shows dust and rock from the collision spilling out into ghostly trails around the asteroid. The debris appears to form a comet-like tail, which is influenced by the asteroid's gravity. You can learn about these stories and more in the March 10th edition of The Downlink, our weekly newsletter. Read it or subscribe to have it sent to your inbox for free every Friday at After years of hard work and anticipation, The Planetary Society's member community app has launched for all of our members. Ambre Trujillo, our digital community manager, is here to talk about the community's launch and our upcoming welcome festival on March 18th. Hi Ambre.

Ambre Trujillo: Hi.

Sarah Al-Ahmed: We did it. Our member community is finally launched. How are you feeling?

Ambre Trujillo: It's a whole amalgamation of relief, and so much excitement. I am just so excited to see it up off the ground. I know that this has been a work in progress for The Planetary Society for two years, and now it's off the ground, and it's good to see that members are enjoying it.

Sarah Al-Ahmed: Oh yeah. I've been having such a fun time playing around in there, and getting to meet people, and people that I've met in past events, too, for The Planetary Society, people that came to our day of action, things like that. It's really nice to reconnect, and as someone who spent two years working on this project, getting to hand it off to you so you could work on it, it's so satisfying. I'm so happy.

Ambre Trujillo: Well, I have to say that the whole team really worked exceptionally hard on it, and you have built such an amazing foundation, and for me to just take your baby and cradle it into what it is now, I feel honored to be able to take on the great platform that you guys were able to create.

Sarah Al-Ahmed: It was a team effort. It took a lot of us.

Ambre Trujillo: Yeah, definitely.

Sarah Al-Ahmed: It went down perfectly. How did the launch go?

Ambre Trujillo: I am very happy to say that it went off essentially without a hitch. Like I said, the team really prepared for this, and because of that, we have over 1000 members in our community already, and it's only been a couple days. And everybody's in, they're engaging and they're meeting each other. This is what we wanted. We wanted to create a community for our members to connect, and that's exactly what's happening, and I am absolutely ecstatic that it's gone well.

Sarah Al-Ahmed: Yeah, and you and I are really familiar with what this platform does, and how people can connect within it. But for anyone who might not be familiar with our new member community, or who might be thinking about joining on for Planetary Society membership in order to gain access, what can they do within this app?

Ambre Trujillo: To start off, it's a membership perk. So this is considered our digital member community, and you can access it two ways, both our desktop and our app. So we officially have an app, and it's a place built exclusively for Planetary Society members. Here they can connect, as I said, with fellow members from around the world, join exclusive live events, and delve deeper into the cosmos and all of the amazing missions that explore them. So it's a place that no matter your expertise, you can come in, and you can just talk to people about your love for the cosmos. And with my background, I didn't have a place for a long time to go. I didn't know exactly where I fit in the space industry, and it took me a really long time to find it. And I wish that I had a community like this starting out, because what took me a decade of being able to find where I fit in this place, is curated for not only people like Ambre 10 years ago, but people like Ambre now, who has a little bit more knowledge, and has a little bit more expertise. And it's just a great place to go, no matter your knowledge level, which is really cool. It's a very special place.

Sarah Al-Ahmed: I love hearing you say that, because similarly, I feel that there were so many times in my life where I felt like people didn't understand my level of nerdiness, or I was seeking that community that wanted to talk deeply about the universe and our place within it. And I wish so much I had had this earlier, but that's okay, because now we all get to play in it together, which is fantastic. And there are so many different ways that you can play within it. It has this beautiful social media feel to it. Yeah, I wake up in the morning and I get to scroll my space feed. It's amazing.

Ambre Trujillo: You can have a daily feed, which is what it's called. You pop in and you see what everybody's been up to or there's these things called Spaces where you can go in and look at particular things that you might be interested in. Maybe you want to look at space policy, what have people posted about on that? What are the updates? And one of the coolest parts, I think, is that you get to mingle with The Planetary Society staff. So you can go in there and you can talk about space policy with Casey. You can go in and you can talk about books and movies and TV and gaming with Sarah. The fact that you can go in there and just connect with us, I think is very cool. It's nice to have a connection with our members on that level.

Sarah Al-Ahmed: Yeah.

Ambre Trujillo: And there's also a great feature, live events, which is fun, and I'm excited to roll out even more of those coming out in the coming months.

Sarah Al-Ahmed: And we have a very special event that's coming up soon on March 18th as well, right? Our welcome festival?

Ambre Trujillo: Yeah. So we have our welcome festival, which will be on, as you said, the 18th, which is a Saturday. And it's going to start off with a welcome from Bill Nye and I. It's hosted by Mat Kaplan, and we're going to bring on Heidi Hammel, who was just named one of the 20 most influential women in astronomy and astrophysics, and who happens to be the vice president of our board as well. And she's going to do a little presentation on JWST, and then we're going to have Jean-Luc Margot and Megan Lee talk about their study project, which is amazing. Afterwards, we're going to have a meet and greet with members. I'm excited. It's going to be a fun day.

Sarah Al-Ahmed: Oh, it's going to be a good time. I don't always like working on Saturdays, but I am down for this. So if anybody is interested, how can they get into this community? Where can they find it?

Ambre Trujillo: As we mentioned, it is exclusively for our members. It's a great membership perk and it doesn't matter what level you're at. We start at $4 a month. So you can go to That'll take you to our member community where you can, if you're not a member, you can sign up to be a member, or you can also just visit our website and join through there. And you'll be able to access the digital community specifically from the join link.

Sarah Al-Ahmed: And you can also find it on the Google and Apple app stores if you want to just get it straight on your phone. Again, you will have to be a Planetary Society member, but that's okay. And this has been so much fun, and thanks for coming on to share some of that joy about this launch with me and everyone listening. Because this has been something we've been working for years, and we feel like we've finally put the society in The Planetary Society, so quite a moment.

Ambre Trujillo: Absolutely. I agree, and thank you so much for having me, and I hope to see more members come in. And if you haven't joined just yet, I'm excited to meet the members in our digital community, and I'll see you on the digital realm.

Sarah Al-Ahmed: See you there everyone. Thanks Ambre. As we said, you can find our member community in the app stores. If you're already a Planetary Society member, you can also access the community on your web browser at Another SpaceX Crew Dragon has recently delivered four astronauts to the International Space Station. The SpaceX vehicles and the Russian Soyuz capsules are currently the only human rated craft visiting the ISS. That's something that may soon change, as Mat Kaplan, The Planetary Society's senior communications advisor, reports.

Mat Kaplan: The NASA SpaceX Crew-5 mission is actually the ninth time a Crew Dragon has carried humans into orbit. Remember the Boeing Starliner? Otherwise known as the CST-100, NASA originally expected both vehicles would be put to work at about the same time. Now, nearly three years after the first Crew Dragon success, the space agency and Boeing are making the final preparations for the Starliner's first crewed mission. Here's Steve Stich, NASA's manager of the Commercial Crew Program.

Steve Stich: We're about 80%, I would say, through that work. I mean, we'll continue to work through that. And then really the next big event with Starliner on the vehicle is loading propellant in the service module. And if you remember, we have a 60 day window we want to go to launch within once we load that propellant, and so we'll have a decision in early March relative to when to target loading the vehicle, and then how we proceed toward launch.

Mat Kaplan: Stich was part of a February 17 briefing about the upcoming mission. With him was Mark Nappi, Boeing vice president and program manager for the CST-100 Starliner.

Mark Nappi: So we're excited about the CST mission. We have some incremental decision points ahead of us based on the ISS availability, and the work that we have going forward. We'll continue down that path, and like Steve said, we're going to take it very slowly and make sure that we address everything that needs to be addressed.

Mat Kaplan: Nappi described five areas of development, or swim lanes that have been addressed since the Starliner's troubled first flight. That was back in late 2019, when the uncrewed capsule failed to rendezvous with the ISS. It would be two and a half years before Boeing would try again, this time achieving an almost completely successful mission. The company and NASA are satisfied that they can safely put two astronauts on the next flight. Barry Wilmore and Sunita Williams will be at the controls, as an Atlas V rocket carries the craft into low Earth orbit.

Mark Nappi: It's important to remember that this is, like Steve said, the final stage. We've done our designs, we've tested this hardware, the analysis is all done. So now this is the, let's wrap it all up in a bow and make sure that we did what we said we were going to do, and we have all the artifacts to prove it. And that's what we're going through at this time.

Mat Kaplan: If all goes well, the first operational Starliner mission will happen sometime in 2024, with just one flight per year following it, unless NASA contracts for more. For Planetary Radio and The Planetary Society, I'm Mat Kaplan.

Sarah Al-Ahmed: Here at The Planetary Society. We believe that space is for everyone no matter where you come from, your level of understanding, lifestyle, or abilities, we all deserve to share in the passion, beauty, and joy of space science and exploration. Our guest this week, Dr. Kim Arcand and her colleagues at the Boston area Chandra Labs are working to find new ways to make space images more accessible to people with low or no vision. Their new album, Universal Harmonies, is a collection of sonifications of deep space objects observed by NASA's Chandra X-Ray Observatory. This space telescope observes some of the most extreme objects in the universe, black holes, exploding stars, and clusters of galaxies to name a few. Sonification is the process of representing data or information as sound. This technique allows people to convert data that's usually presented visually into an auditory form. Sonification is used not only to make data more accessible, but to explore and understand complex data sets. It provides a different way for us to explore the wonders of the cosmos. Kim Arcand is a visualization scientist, and emerging tech lead for NASA's Chandra X-Ray Observatory, headquartered at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, USA. With the help of her colleagues, NASA, Harvard, the Smithsonian, the Canadian based group called SYSTEM Sounds, and their producers Atsua Sounds. Their new album, universal Harmonies was released on March 10th. Hi Kim, welcome to Planetary Radio.

Kim Arcand: Thanks, Sarah. It's really great to be here.

Sarah Al-Ahmed: Congratulations on the release of Universal Harmonies. It just came out last Friday, so this is a perfect moment to talk to you about this.

Kim Arcand: Yeah, I'm super excited for sonifications to have more of a moment, if you will, out there in the world.

Sarah Al-Ahmed: Absolutely. This project has been years in the making. How would you describe this album?

Kim Arcand: The project of sonification in general has, I feel like, been a long time coming. For me, it was a slow journey to get here. I've been working for NASA's Chandra X-Ray Observatory for almost 25 years, and spent the first few years of my career really just working on images, and started moving into 3D modeling and 3D printing to be able to make it more inclusive and more accessible. But we were still really missing an important piece of that accessibility, and also that translation. And so when I started working with my colleagues at SYSTEM Sounds to create two-dimensional data sonifications, which is just the process of taking the image and turning it into sound, I really felt like that was a moment where we had finally filled that last gap that we had. So it has been a journey, but it's been a really fabulous one.

Sarah Al-Ahmed: And I found the sonifications in this album to be really calming and ambient, something that might be good to listen to while you're meditating or working, which gave me a really good laugh because then I read articles about, it was specifically the sonification of the Perseus Cluster, and they described it as this cosmic horror, and this terrifying howling of outer space. And I guess it really depends on what object you're listening to.

Kim Arcand: It does. Yeah. We've heard lots of different feedback about these sounds, because some of them are, like you said, quite relaxing and calming, and some of them are a little bit more peppy and joyful, and some are perhaps a little eerie and strange sounding. And we actually did a survey, a sonification study, if you will, on these pieces about a year and a half ago. And that was pretty much the feedback we got. It was very much across the spectrum of, this made me feel calm, this made me feel relaxed, this made me feel interested, this made me feel excited, all of those emotions. And I think that really speaks to the power of sound and music in general. It embeds itself in your imagination, in your mind, in a different way. And I think that's an exciting thing for astronomy to be a part of.

Sarah Al-Ahmed: Yeah. When I was in college, I took a class on the politics of music, and something that really stuck with me was the professor's description of how, before humans had even invented language, we were singing songs, and pounding on things in the wild, that music is deeply embedded in our ability to communicate and imagine. And I always think of that when I experience things like sonifications of space. What a journey from the beginnings of human music to something like this, where we're taking music and making it scientific and accessible. It's fantastic.

Kim Arcand: Yeah, that class sounds awesome. And yeah, it's this idea, we're taking data that has been collected by these satellites that orbit the earth, that are out there looking at these things so far away from us, millions if not billions of light years away. And we're able to take that data, and translate it into sound, and it is really exciting. It's like a lovely merge of the science, the technology, and a little bit of the art.

Sarah Al-Ahmed: How did you originally get interested in sonification, and how did that lead to the creation of this album?

Kim Arcand: There's a few different steps that I had to take. First it was the introduction to a very dear friend of mine, Dr. Wanda Diaz. She's an astronomer and computer scientist. She went blind when she was a teenager, and she's talked about how she would be in classes, and professors would just be writing math equations on a board. And she felt like she could not be a scientist in that way. And so her PhD thesis was essentially on the fact that scientists, that people, can learn to become better listeners of scientific data. And that's always been an inspiration point for me. We started working with my students in a lab before COVID on how to take virtual reality, and attach data sonification to it in that sort of geospatially aware way. And we were working on that, and then COVID hit and it just... Everybody went home, and things were just changing, and that's when I contacted my colleagues, Matt and Andrew from SYSTEM Sounds, because I had met them at a conference a few years prior. They were doing interesting work on turning two-dimensional images into sound. And I thought, well, maybe that's where we could go right now. Right? It's a pandemic. Things need to be simplified. Let's see how we can do this. And that's where we started. And I had a list of my favorites, my best hits, if you will. The greatest hits that I was hoping would really translate well from the Chandra X-Ray image into the Chandra X-Ray sound, and all the other NASA data involved as well. And we've just been going through that list, and really trying to create something new that adds value, hopefully for people in an interesting way.

Sarah Al-Ahmed: When I first learned about this, I was actually very moved, because I know so many people who are vision impaired who want desperately to find a way to interact with these beautiful space images. So projects like this are just a perfect way to bring more people into our space family.

Kim Arcand: Exactly. Exactly. And I think this kind of public communication project's important because it's step one. So in that survey that I mentioned earlier, one of the questions was about, what did this make you think of? And a number of people who are sighted who took that survey noticed that this made them think about how other people access information of the universe. And so that was, I think, a really exciting thing, that this was a moment that people could just increase their own awareness of how other people interact with data.

Sarah Al-Ahmed: And Chandra's a unique case because it's an x-ray telescope, so necessarily humans cannot see that part of the spectrum, and we have to make changes to how we share that data, in order to make it accessible to anyone at all. So this is a perfect segue between taking the images and finding a way to interpret it and share it with more people, make it accessible to more human senses.

Kim Arcand: Exactly. I love that talking point in general, and it's something that I like to talk about a lot, because this is x-ray data that no human eyes can ever naturally see, and that process of translation is important. You have to take something that's essentially numerical, and translate into the representation of the object in a kind of light that humans can't detect, in this case x-ray light, but also even with infrared light from the James Webb Space Telescope, or different kinds of light from the Hubble Space Telescope, for example. In that process of translation, it's like taking something and translating it from English into, say, Mandarin. You do have to have choices that you're making as the translator. You're sticking to the story, you're being authentic, you're being truthful, but not every word is going to be exactly the same in the two different languages. So that process of translation I think is really important to consider, not just for the image, but also for the sounds as well. It's just moving something from one form into another, but sticking to that scientific truth.

Sarah Al-Ahmed: And how do you sonify these images? Because I imagine that there are many different methods to do so. What angle do you take across the image? What tone do you associate with certain colors and brightnesses? How does that work?

Kim Arcand: Yeah, so there are a number of different ways to do this, and different researchers are applying different methods for their own needs. I'm actually working on a project with my students again, where we're taking a sort of auto approach where you upload an image, and it just does a very basic sweep across the image from left to right, but you do have an independent movement to be able to assign, trace the pixels if you were, with your location, with your mouse, with your finger, whatever. And that will just create some very simple sounds based on the types of stuff in that image. But this project is a sonification project that I've been working on for the past few years with my colleagues. It's more of a bespoke process. We're doing a mathematical mapping, and that mathematical mapping is done using Python, and then it's brought into essentially a sound engineering platform, where you're then tweaking the sounds based on that scientific story. But what's really important is your input. What is the image that you're starting with? What is the scientific information that you're starting with? That drives every part of this translation. And so if it's a long, wide image, we're going to do a pan typically from left to right. If it's a tall, skinny image, we're going to pan from either top to bottom, or bottom up, depending on the data. If it's a circular shaped object, we're going to go from the middle out. So there are all of these different techniques that we've been applying to make sure that the science of that object is something that will really make sense. And also working with our partners who are blind or low vision to make sure it makes step along the way, to make sure all of that sciencey goodness, if you will, is really being communicated, and that there's value being added in that meaning-making process.

Sarah Al-Ahmed: How do you determine whether or not an image would be good for sonification?

Kim Arcand: Oh, that's a great question. And it would really depend. Sometimes something you think will make a great sonification goes a bit wah-wah, and so it is a bit of trial and error. So far we've had mostly successes. I've found, at least the Chandra data so far really does seem to lend itself very well to sonification. And again, I have to give major props to my colleagues that help with all of the techniques and shifting these things from something you can see into something you can hear. But there are definitely cases where it's not quite as easy. An image of the sun, for example, might not be the simplest thing to sonify, whereas an image of an exploded star seems to be quite easier. So there are different kinds of data that will give you different kinds of results.

Sarah Al-Ahmed: That's good to know, because that's how I was listening to this album. I was bringing up the images and trying to imagine what direction are we sonifying across this image? What was the process? So that's really informative, that helps, because some of them, it's like, this is definitely different from the previous song.

Kim Arcand: Yes, yes. And it really is the science story that's driving it. But what we do do, and what I think is important to do, is we always have notes with every object that we release in this form, and it provides that really detailed description of how it's being sonified, and why those choices are being made. So you'll find the music notes as to the pitches that are being used, and if it's panning one way or another, and what kind of musical instruments are being applied, if any, that sort of thing.

Sarah Al-Ahmed: Most people I've encountered think of sonification as a fun niche thing, maybe something that's used for accessibility and entertainment. But each new way of expressing data presents an opportunity to catch things you might not have noticed before. So how can we use sonification for scientific purposes?

Kim Arcand: Yeah, 100%. And I definitely totally understand the skeptics, by the way. This is not going to be for everybody, but the point of this isn't actually for it to be for everybody. We went into this project with a very specific mission of continuing to work with our colleagues and our community members who are blind or low vision. And so at the end of the day, that is really a key requirement of this project. But secondary to that, as we talked about earlier, music and sound, your human senses are tuned to those in different ways than they're attuned to sight, if you happen to have both of those senses. And there is a power, I think, in leveraging whatever senses you have available, whether it's touch, whether it's sight, whether it's sound, I might stop at taste or smell. But for me, having multiple senses, these multiple modalities, can be really important. I've found it myself, even with some of these objects that I have made the images for. I have stared at this data for years and years and years, and I know these pixels inside and out, and the first time I'll hear a complete sonification, I'll find something new. The Galactic Center is a great example of this. It has different kinds of light. It's got infrared light, it's got a near infrared optical light, and then it's got the x-ray light, and all three different kinds of light are working together to show us a glimpse of the inner 400 light years of our Milky Way's core. And when you look at that image, it's beautiful, but it's very dent, it's very rich. There's a lot of activity. This is a very hustle bustle region of space. When you listen to the sounds, your ears can process things slightly differently. And you can hear these moments where one or two of the different types of light, one or two of those different sounds are just harmonizing beautifully. And then in the next moment you'll hear a solo, and I'll have to look at that image that I know like the back of my hand, and be like, "I've never noticed that before." So there is a whole area of research where this is being used for scientific study, and they're actively working not only to understand how it can help the scientists, but also what kinds of different data produce different results that we can learn in different ways. It's all about this idea of delivering data differently, as a colleague of mine has said, and what the power in that might be. I think it's young days still, but it's to me a very exciting field.

Sarah Al-Ahmed: We'll be right back with the rest of my interview with Kim Arcand after this short break.

Ambre Trujillo: Ready to level up your space game? Hi, I'm Ambre, digital community manager for The Planetary Society, and we are launching our brand new digital member community. This is a place that's built exclusively for Planetary Society members. Here you can connect with fellow members from around the world, join live events you won't get anywhere else, and delve deeper into the wonders of our cosmos, and the missions that explore them. It's all about putting the society in The Planetary Society. If you're not yet a member, now's the time to join at I'll see you on the digital frontier.

Sarah Al-Ahmed: After so long listening to these sonifications, can you recognize different regions of space or even different space objects by their sounds?

Kim Arcand: Yes, now I can. Yes. I have a good oral memory, I guess, but yes, I am definitely very well attuned to them now. It's pretty exciting because I think there are just different types of objects that we can do really cool things with. And for research, for example, variable stars is one area where these stars that are changing all the time, and there are all these plots that you can look at to understand them. But when you can listen to that data, your brain can process it a little bit easier, and a little bit faster. It's like that cocktail party effect. You're at somebody's home, you've got somebody sitting next to you on the couch and there's a conversation going on. But you can also hear someone in the kitchen. You can hear a dog moving around by the entryway. You can hear somebody sitting down at the dining room table. Your brain can process all this data, remove what you don't need, and focus on the conversation that's going on next to you, or what's happening, these cues that you might need elsewhere in that party. And I think it's really useful for us to harness that potential when we're trying to understand this big wide universe, this big wide world.

Sarah Al-Ahmed: Can you tell the differences between a black hole and a galaxy? What's the sound difference there?

Kim Arcand: Well, yes, because usually when we're sonifying the data from, say, a black hole, it's going to be really close in, and you can identify it by the pulsing sound that you get. It's a different, rhythmic sound. When you are sonifying something like a galaxy, that's going to have a lot of stars in it, quite literally billions of stars in it. And so all of those little points of lights are typically going to be picked up in a sonification, and so it sounds very staccato. There's a lot happening there. When you're looking at an area of star formation, where it's pillars of gas and dust, or waves of gas and dust, it has a very different feeling to the sound, more of waves of sound versus just the staccato of a galaxy, or the rhythmic pulse of a black hole. So yeah, these objects, they do tend to have their own characteristics.

Sarah Al-Ahmed: I remember listening to the sonification of data from LIGO, the Laser Interferometer Gravitational Wave Observatory. That's a mouthful. For anyone that's not familiar with that instrument. It measures gravitational waves, and the collisions of compact objects like black holes and neutron stars. And just listening to the sound of it, it's one thing to explain the collision and the physics of these objects, but hearing them get closer and faster and spiral in toward each other, that felt like a more accessible way even for me to understand that data. So I'm really excited for everyone to get a chance to listen to Chandra data as well.

Kim Arcand: Absolutely. And I think the Chandra example of the Perseus Galaxy Cluster is a great one here. That is a re-sonification of something. So it's this very super massive black hole at the center of a cluster of galaxies, and it's sort of burping out into the surrounding hot gas, a medium, if you will. And because there's that medium, those burps are pressure waves which are causing sound waves. And you can use lovely math, as our colleagues Andy Fabian et al did back in the 2000s, to be able to understand that that's one of the deepest notes in the universe that's being created. It's a B flat, about 57 octaves below middle C. And so that sound is out there in the universe, but this is hundreds of millions of light years away, and there's not enough stuff between us and it, so we can't ever hear it directly. It's too low. It's hundreds of piano keyboards below what humans can hear. But now because of sonification, we can take that note and bring it back up 57 octaves into something we can hear. And to be able to perceive, to explore, to understand an object like a black hole through sound, is I think a very exciting thing, because these are things that the gravitational pull is so strong that we cannot see any light of a black hole itself, because there is none. And ti be able to instead understand it through something like sound is, I think, a very unique opportunity, as you said, to make something that's so esoteric feel a little more accessible, perhaps.

Sarah Al-Ahmed: Do you have any favorite tracks on this album?

Kim Arcand: Yes, definitely. Oh, I have a couple favorites, and actually two of them I've already mentioned, Perseus for sure. That one just blew me away. And the Galactic Center was one of our first ones, and it's a very... I'm a former band and choir geek, so the Galactic Center just, I don't know, it just gives me chills still. Another favorite of mine is the M51 Galaxy. It's an interacting galaxy, the Whirlpool Galaxy. It's this beautiful spiral structure, and we've got four different kinds of light all layered together, optical, x-ray, ultraviolet, and infrared. Each layer is played individually, and then together, and it's with a choral sound. It reminds me a little bit of Eric Whitaker's music. I don't know if anyone's a fan here on the radio.

Sarah Al-Ahmed: I love Eric Whitaker.

Kim Arcand: It's beautiful choral moments, and we can't quite compare it to that, but it has these moments of these, you can hear these little diva moments of solos in that upper, upper, ultra-high soprano sound, because these are synthesized choral sounds, and you've got these beautiful rich bass notes coming in from the infrared. And it's just when you hear it all together, whoa. And when you hear all of the individual components, you can pick up different facets of what that sound is telling you. You can hear the stronger spiral structure in the optical, and then once you get to the x-ray, you're getting more of those staccato bits, those little diva moments from that ultra-high soprano, because you're picking up things like x-ray binaries, two stars dancing together, exploded stars, smaller black holes, that kind of stuff. And you can hear that in the data, and I think that's really exciting. So that one is definitely a favorite. And the other favorite, if I could pick one more, is the Chandra Deep Field South. It's an image that a scientist can love, but it's hard to communicate the excitement of that image, when the image itself looks like you've taken a black canvas and splattered some colored paint on it. The story of it, that we pointed Chandra at a patch of the sky for an awfully long time, it's the deepest x-ray image we've ever gotten, and Chandra found thousands of black holes just hanging out there in the universe, way, way back in the early days of the universe. When you hear the music, it reminds me of Imogen Heap. I don't know if you like her music.

Sarah Al-Ahmed: Yes.

Kim Arcand: She's an artist from the UK, and it's got that sort of lovely melodic, I don't know, almost a blurriness to it. And the sound is based on the energy levels of each of the black holes that were detected, or the galaxies that have super massive black holes at their cores that were detected in that image. And you can just hear, it's just a choir of black holes all hanging out together in the universe, and I think it's quite lovely.

Sarah Al-Ahmed: That's beautiful. I loved that Deep Field. Listening to it was just such a wonderful experience. I think for me though, just because of the timing of it, the Supernova 1987A track.

Kim Arcand: Oh, yes.

Sarah Al-Ahmed: Because I was born just a few months after that happened, so it's-

Kim Arcand: Oh, that's cool.

Sarah Al-Ahmed: One of my favorite space moments.

Kim Arcand: Yeah, that's cool. And I like that piece too because, well, I love that supernova. I'm very partial to supernova remnants for sure, but we actually use a bit of sound from our colleague Christine Malik. She is an amateur astronomer. She's a colleague that works with us. She's blind. She's been blind since birth, and she's a musician as well. And we used some of the sound from her music as the piece going around Supernova 1987A. So that one was very special as well. But I guess I feel like they're all special, clearly, at the rate I'm going. Can't pick a favorite child, I guess.

Sarah Al-Ahmed: I know that each of these tracks comes with little details, but are there any specific little moments that you wish you could explain to people as they're listening?

Kim Arcand: Oh gosh, yeah. I mean, all of them have these absolute moments of awe for me, and I'd love to be able to talk about that. The Pillars of Creation, I think, is another great one. That image is very famous. Everybody loves the Eagle Nebula and the story that there are these tall columns of gas and dust detected by Hubble where baby stars are being born, I just think is lovely. And I think the tallest pillar might be about four light years tall, if I recall. So light years are the distance that light travels in a year, so about 10 trillion kilometers, so say 40 trillion kilometers. And so with that image, the Chandra data is the slightly older stars that are around it. And so we really wanted to contrast the difference, the texture of those star formation regions of gas and dust from Hubble, and then those beeps and boops from Chandra. I'd love to be able to talk about the whys, because I think it really adds to the story. When you're scanning across that pillar of gas and dust, it really changes. You can hear that dimensionality of the structure through the sound, which I think is really quite lovely. And then for it to be offset by all of those more robotic sounding beeps and boops from Chandra, it's very otherworldly, I guess. Unintended or whatever, it was just, yeah, it's a very special moment.

Sarah Al-Ahmed: As you said before, sonification is just one way that you're trying to make space more accessible for people. You recently came out with the book about 3D printing space imagery, which I love because I'm super into 3D printing. It's called Stars in Your Hand: A Guide to 3D Printing the Cosmos. What will people find in that book?

Kim Arcand: Oh, thank you. So kind of you to mention that. Yes. So 3D printing has been a love of mine for a while. We started this project, well back in 2008, I think we first started working with three-dimensional data, and it was a very new topic to me. I really didn't have a ton of experience in it, but essentially you're trying to figure out which of the light's moving away from you, and which of the light is moving towards you. And there are a number of different techniques that you can do that, but using the Doppler fact is a really great way. And so we were working with a scientist, Tracy Delaney, back then on Cassiopeia A, to move it into this three-dimensional world. And we had the 3D model from her, but we really wanted to 3D print it. And we figured it out, we learned how to do that, and that started a love affair for me with 3D printing. And I've been very eager ever since to move more and more objects into 3D. And in the book, it's essentially a collection of all different kinds of objects from colleagues all over the world that have done really cool things to be able to make these objects interesting through a 3D process, and also accessible through that tactile quality. It's great to have these 3D prints when you're working with kids, for example. Kids love to touch stuff. And so it's so fantastic to be able to 3D print a portion of the moon. You can feel all of those dents and bangs from all of the beating up that's occurred to the poor moon over many, many millions of years. And having those different ways of understanding information through texture, through tactile quality, is a really another, I think, exciting way to just deliver your data in a different way, deliver your data in a way that can make people think about it in a new way, perhaps, that can make people excited to even explore it in the first place. So yeah, there's a number of different objects in the book from, as I mentioned, colleagues around the world, different kinds of exploding stars, tactile plates of galaxies, a lot of solar system objects, because those are, as the nearest objects to us, they are the easiest to figure out in three dimensions. So it's a little tiny guide to all of the cool stuff that's available in 3D in astronomy these days.

Sarah Al-Ahmed: I'm going to have to get this book because I love 3D printing space objects just for fun.

Kim Arcand: It's fun. Yeah.

Sarah Al-Ahmed: There was this moment for me after the last total solar eclipse in the United States, and I was working at Griffith Observatory after having experienced what was just visually one of the most beautiful moments of my life. It was so moving, and I encountered a patron at the observatory who was vision impaired and wanted desperately a way to experience this thing that everyone was ranting and raving about. So I went home and I 3D printed a simple, like a lithophane, actually. It was just a little bit elevated in the places where it was brighter, and I never encountered that person again, but I carried it with me for about two weeks after that, and people's reaction was wonderful. Just being able to give that to someone was such a beautiful moment, and I love the idea of finding what else is in there to share with people.

Kim Arcand: 100%. I can actually say I carry a 3D print of an exploded star in my purse at all times. I am never without at least one or two 3D prints, 3D models, because no matter where I am in the world, no matter who I'm talking to, I can guarantee you I'm going to crack one of those models out and be able to talk about it. And I love being prepared to talk to people no matter where they're coming from, no matter what their perspective is, whether they're sighted or not. And it just makes me feel great to have the capability to be able to do that. And so, yeah, 3D printing has just been a tremendous gift to how I approach things, because it's made it so much easier for me to be able to explain things, and to be able to offer connections. Yeah, I really love that.

Sarah Al-Ahmed: So what's next for you? Are there any other projects we're working on, or images you're working to sonify right now?

Kim Arcand: Yes. Yes and yes. So we are working on new projects. I'm actually working with a young composer right now. Her name is Sophie Kasner, and we're taking some of these sonifications and translating them into something that can be played by instrumentalists. Small ensembles, for example, that could play the Galactic Center. So picture flute, oboe, violin, cello, and some percussion being able to play this data of our own Milky Way's core with our own instruments, because that's a request we get a lot. There's always, always a musician in the audience who wants to know, can I play these sonifications? So we're working on that. And we have some other projects too. We're still continuing with the sonification. We've got some really exciting new sonifications that we'll hopefully be releasing a little later this year, and other stuff too. It's been a bit of a wild ride. I feel like I've been rewarded tremendously for trying these things, and part of me feels like I'm just having fun with this. And so the public response to these projects has been overwhelming, overwhelmingly positive. And when you're rewarded like that, well, it's like, okay, of course I'm going to keep doing more, right? Because this is giving some people joy. This is giving some people new ways to learn. This is giving people new ways to access data. This is giving people a new way to explore our universe. Why wouldn't I want to keep doing this kind of fun stuff?

Sarah Al-Ahmed: And I'm sure there are a lot of people who cannot wait to listen to Universal Harmonies.

Kim Arcand: Oh, thanks. It's been really exciting to be a part of that project. Having the ability for someone to make a record out of these sonifications so that you can play it on your own turntable, it's a whole other level. The first time I heard the sound on the turntable, I was blown away by how warm and immersive it sounds, very different from the digital sound I was used to on my computer. Because I'm not a total sound aficionado here, as far as, I don't have the best headphones and all of that stuff. And so having that moment of just listening to it on the album, one piece after the next, oh, it was very, very cool. And yeah, I was sold. I'm now sold on vinyl. I get it. I get why it's so neat. I get why people love it.

Sarah Al-Ahmed: Kim, you've led such a distinguished career, and I want to thank you for everything you've done to make space for everyone. It makes me so happy. And there are so many more people that are going to be able to experience this data because of your work, and your colleagues' work. So thank you.

Kim Arcand: Oh my gosh, thank you so much. This is not just me though. This is hundreds of colleagues around the world that all lend their talents, their data, their skills, and yeah, I couldn't do it without any of them. So it's a group effort.

Sarah Al-Ahmed: Always. Thanks for joining me.

Kim Arcand: Thanks, Sarah.

Sarah Al-Ahmed: I loved that conversation with Kim Arcand. The intersection of music and science is always beautiful, but when it provides us new ways to share and explore space together, it's even better. Now it's time for what's up with Bruce Betts, the chief scientist of The Planetary Society. Hey, Bruce. I'm back from outer space, and by outer space, I mean back from recovering from COVID.

Bruce Betts: Oh, sounds awful. And yeah, no, I guess that was worse than leaving me with Mat. But anyway, I'm so sorry that you went through that and are still, I guess, recovering. So I'm also very glad to be seeing you two dimensionally.

Sarah Al-Ahmed: I'm so grateful that I managed to come through it, but as Mat said last week, I received just a huge number of messages, people wishing me well, hoping I got better, and it was just a light in my life as I was laying in bed, unable to really do anything. So I really want to thank everyone that wrote me. I haven't been able to respond to everyone yet, but know that I read your messages, and I really appreciate it.

Bruce Betts: Oh, that's nice. You know what we should talk about?

Sarah Al-Ahmed: The sky.

Bruce Betts: Sure. Still there. Saw it last night, super bright Venus, below it, bright Jupiter, dropping, dropping, dropping as the days pass. It'll be disappearing soon. Catch it while it's hot, or something. Anyway, still looking stunning, Mars still pretty high overhead, hanging out in the general region of a bunch of bright stuff, including Orion. Maybe a little premature, but if you're really into Saturn or the horizon just before dawn, visible very low in the east before dawn, Saturn's starting to come up, but it'll just be getting higher and higher, and eventually it will reach a point in the sky in a few months where I'll be able to see it without waking up in the middle of the night.

Sarah Al-Ahmed: At this point, I would be glad to go out at that hour to go see some stars. I've been inside quarantined for so long, I missed that beautiful moment with Venus and Jupiter close to each other in the sky.

Bruce Betts: Hey, I took pictures. It looks like two dots.

Sarah Al-Ahmed: Two beautiful, shiny, bright dots.

Bruce Betts: Oh, and I actually got three other little dots in my pictures. Some Jupiter moons.

Sarah Al-Ahmed: Oh, awesome.

Bruce Betts: So that's something. Anyway, that's the night sky. On to This Week in Space History. 1958, the US launches Vanguard 1, which was one of the early successful spacecraft, next successful one after Explorer 1. But it holds the record for being the longest object in orbit around the earth, or in space, that was sent by humans. It's still up there from 1958. Another object to mention, an object? Sure. Mercury. In 2011, Messenger became the first spacecraft ever to go into orbit around Mercury, in This Week in Space History.

Sarah Al-Ahmed: I love those pictures. So few times have we had an opportunity to get a good glimpse at Mercury.

Bruce Betts: Onto Random Space Fact.

Sarah Al-Ahmed: Ooh, a nice quiet one that was calming.

Bruce Betts: I didn't want to upset you. So the Constellation Crux containing the asterism the Southern Cross, visible to everyone hanging out in the Southern Hemisphere and quite recognizable, interestingly was visible to the ancient Greeks a few hundred years BC, because that was before it dropped below the horizon and out of the view of anyone that... Now it's around plus 20 degrees latitude, that you have to be below that to have a chance to see it. So why? Why did this happen? It was not magic. It was the very weird Earth's procession. So like a top that's spinning on its axis traces out a circle as it loops around, amazingly Earth does that on a 26,000 year cycle, changing our North Pole angle, but also affecting things like what constellations can be seen from where.

Sarah Al-Ahmed: That's awesome. I had to go all the way to Australia before I got to see the Southern Cross.

Bruce Betts: Me too. Well, actually, I picked up New Zealand and then Australia. So anyway, there's just a little bit of southern sky for all the times I don't properly treat you well. You can enjoy the Southern Cross this evening for me and for Sarah. Let's go to the trivia. We got a couple to catch up on because someone wasn't here last week. So we're going to do two answers to contests. We'll start with the oldest question, which was how many missions to Mars were tried but failed for any reason before Mariner 4 was the first successful mission at Mars? How did we do, Sarah?

Sarah Al-Ahmed: We did well, and it's actually really funny. So this question and the question after it from last week, both of our winners are from the UK, which seems cosmically funny to me, considering that I caught COVID at a Dr. Who convention. But the winner for this question was Paul Mundy, and the answer is that there were six failed missions that attempted to get to Mars before Mariner 4 succeeded, five of which were from the USSR, and one from the United States. So Paul, you're going to be winning a Goodnight Oppy 12 ounce thermal mug.

Bruce Betts: Yay.

Sarah Al-Ahmed: What was our second question?

Bruce Betts: From a robotic sample return mission, so not crewed, what was the largest mass of samples returned by a single mission? How about that one?

Sarah Al-Ahmed: Yeah. Our winner on this one is Stephan Whitehead, also from the UK, and the answer is, it's the Chinese National Space Administration's Chang'e 5 Mission, which went to the moon in 2020, and returned 1,731 grams of material to Earth. That's a little under four pounds. And it's funny, I'm always such a fan of the Chang'e missions, because this is a silly reason, but I used to play the Moon Goddess Chang'e in a video game called Smite years ago. Her Jade Rabbit was so cute. I'm such a fan. Stephan, you're winning a TPS beanie, so we'll send you a nice beanie to keep you warm.

Bruce Betts: You got any more comments for me, or...

Sarah Al-Ahmed: Oh, yeah. I'd like to read a couple messages from listeners, because this one was funny. Mark Dunning from Ormond, Florida wrote to say, "Still getting used to nice Bruce. I guess it's just going to take time." Your niceness to me is weirding people out, Bruce.

Bruce Betts: Yeah, I was afraid of that. I didn't know, I've been trying to check what the etiquette is for how long until I can get more abusive, but-

Sarah Al-Ahmed: Until you can be mean?

Bruce Betts: You played the COVID card, and so now I just don't have the heart. Sorry, everyone.

Sarah Al-Ahmed: Sooner or later it'll happen. And I loved this message too from Eric O. Day from Winchester, Massachusetts who wanted to thank me because in my interview with Meenakshi Wadhwa on the Mars sample return mission, I said that they should put a chomper thing on the little helicopters going to Mars, and that it made his week, and that NASA should officially use chomper thing as the nomenclature for that. Of course, the helicopters will not have a chomper thing.

Bruce Betts: Well, I mean, they weren't going to, but now...

Sarah Al-Ahmed: But now...

Bruce Betts: No, a few people are able to think so far outside the box to put chopper things on extraplanetary... Whatever. Anyway, you got more, should I go on?

Sarah Al-Ahmed: Let's go on.

Bruce Betts: All right, we got something a little different. Name all the countries whose national flag has some representation of the Southern Cross asterism that is part of the Crux Constellation. Go to

Sarah Al-Ahmed: And you have until Wednesday, March 22nd, 2023 at 8:00 AM Pacific Time to get us the answer. And if you win, we have a really special prize. As you heard earlier, when was doing the interview with Kim Arcand, they have these beautiful vinyl LP versions of their new album, Universal Harmonies. So if you win this, we will send you one of those vinyl records.

Bruce Betts: Wow, that sounds pretty cool. All right. Everybody go out there, look at the night sky and think of the terror that is Sarah. Thank you and goodnight.

Sarah Al-Ahmed: We've reached the end of this week's episode of Planetary Radio. We'll be back next week with Lindy Elkins-Tanton, the principal investigator for the upcoming Psyche mission to investigate a metallic asteroid. Planetary Radio is produced by The Planetary Society in Pasadena, California, and is made possible by our diverse and appreciated members. You can join us as we work to make the space community a more welcoming place for everyone, at Mark Hilverda and Rae Paoletta are our associate producers. Andrew Lucas is our audio editor. Josh Doyle composed our theme, which was arranged and performed by Pieter Schlosser. And until next week, ad astra.