What sound can teach us about our Sun? In this episode, we explore how NASA scientists translate electromagnetic waves from the Sun into sound, and even music. Through this process, researchers are gradually unlocking the Sun’s secrets, from the steady “hum” of the star’s rotation, to the way that solar winds “play” the Earth’s magnetosphere like a harp. This story comes from the podcast NASA’s Curious Universe, and features Host and Astrophysicist Padi Boyd, Sonification Specialist Robert Alexander and Heliophysicist Mike Hartinger.

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View Transcript ▶︎

You’re listening to Twenty Thousand Hertz. I’m Dallas Taylor.

[Saturn sonification in]

As a sound fanatic, one of my pet peeves is the common misunderstanding about data sonification. That’s when scientists turn information - like numbers or measurements - into sound. The creepy soundscape you’re hearing right now is a sonification of radio emissions from the auroras on Saturn, which are similar to the Northern Lights here on Earth.

These signals were captured by the Cassini spacecraft in 2002. But here’s the thing. Radio waves aren’t sound. They’re a type of energy, like x-rays or microwaves. And they don’t create vibrations in the air like sound does. In this case, these waves were oscillating between thirty thousand and eighty thousand cycles per second.

To make it audible, researchers mapped this data onto a set of lower frequencies, kind of like slowing down a really high-pitched whistle until it’s within our hearing range. They also sped up time, playing twenty seven minutes of data in just seventy three seconds. That way, we can hear these patterns more easily.

Now, people send me clips like this all the time and say, “Hey, listen to what Saturn sounds like!” And while I love their enthusiasm, I always want to make it clear… this isn’t what you would hear if you were floating near Saturn with a microphone. There’s no air, so there’s no sound. But when we understand sonification for what it is, it becomes an incredible way to make scientific data accessible… and even beautiful.

This story comes from NASA’s Curious Universe. Here’s Padi Boyd, an astrophysicist and the host of the show.

[MUSIC: Robert Alexander’s musical sun sonification]

HOST PADI BOYD: I have a question for you. What does space… sound like?

[SFX: Rumbling solar wind velocity data and crashing proton cyclotron wave storm sonifications]

Robert Alexander: We’ll see things like material from the surface of the sun that wants to extend outward into interplanetary space. But then it gets caught on a magnetic field line and pulled back down to the surface of the Sun. Every now and then, these magnetic field lines will kind of get twisted up and they’ll no longer be able to keep their hold to the surface of the sun, and they’ll go flying out into space.

Robert Alexander: And when this happens, when we get something like a coronal mass ejection, the amount of material that leaves the sun is oftentimes greater than the entire mass of the planet Earth.

HOST PADI BOYD: This is Robert Alexander. He’s a data sonification specialist that studies the heliosphere, our sun’s sphere of influence in space. Our nearest star is a dynamic and turbulent one. Most scientists turn data about its explosive activity into charts and graphs…

Robert Alexander: Traditionally we would look at that, and it would be a line that would just kind of boop, it would go up and come back down.

HOST PADI BOYD: Robert… translates it into sound.

Robert Alexander: Rather than just plotting it and looking at it, we can also listen to this eruption of particles. And when we listen to it, it sounds like an explosion.

[SFX: Crashing sound of CME hitting Parker Solar Probe]

Robert Alexander: The first time I would play some of these sounds back for a research scientist, and something that had always been a line on the screen was suddenly filling the room with this explosive sound…

[SFX: Crashing sound of CME hitting STEREO A spacecraft]

Robert Alexander: There’s this kind of emotional connection that you can form with it. And it sounds raw, and it sounds powerful in a way.

HOST PADI BOYD: What you just heard there was a coronal mass ejection exploding out of the sun and accelerating to more than a million miles per hour before crashing into the Parker Solar Probe, then traveling 14 million miles an d arriving at the STEREO A spacecraft. How wild is that?

Mike Hartinger: Our specific community who study plasmas and the near space environment, we actually started using sound, back in the dawn of the space age. [MUSIC: Robert Alexander’s musical sun sonification]

HOST PADI BOYD: That’s Mike Hartinger, a heliophysics research scientist at the Space Science Institute and NASA collaborator. Before the first rockets left Earth’s atmosphere, space scientists pointed radio antennae up to the sky, wondering what they might hear… trying to tune into the vast universe above them.

Mike Hartinger: Sometimes it was as simple as you know, you have an antenna and you just listen to what’s coming out of a speaker in real time. And, you would hear things like whistles.

[SFX: Whistler, chorus, and hiss waves from British Antarctic Survey]

Mike Hartinger: People coined the term whistler waves. You would hear this repeatable pattern every dawn that sounded like a chorus, like a human chorus. And the term was actually coined, “dawn chorus…”

HOST PADI BOYD: When NASA started launching satellites, scientists heard those waves again, this time from space.

[SFX: Whistler and chorus waves from University of Iowa’s space physics department]

Mike Hartinger: And so these terms were coined as people were listening to these things to speakers, just when we were starting to launch satellites. And if you listen to these things, they’re really like, ethereal, they’re really beautiful. And they just make you pause and think like, “Wow, that’s… That’s happening, like right above my head. There is this whole invisible world to us, that you kind of interact with, with sound.

HOST PADI BOYD: But what exactly were those early scientists hearing? To understand the sounds of space we have to start… with the stars. Specifically our closest star, the sun.

Mike Hartinger: So, the sun is a giant ball of gas, really hot gas, that we call plasma.

HOST PADI BOYD: From here on Earth, the sun looks like a giant yellow ball… stable and unchanging. But if you could get up close and zoom in…

[Music: Henry Dehlinger’s Cosmic Cycles symphony, The Sun]

Mike Hartinger: You know, of course you’re gonna see this giant yellow ball, but if you look at that yellow ball, even through a telescope, you’ll see there are these little dark spots, that we call sunspots, on the surface of the sun. And they’re constantly changing. Like on a timescale of days or weeks you’ll see them kind of pop up and go away and they’ll move as the sun rotates from our point of view.

HOST PADI BOYD: Those dark regions, the sunspots, are actually cooler in temperature than the rest of the sun. But they’re also the sun’s most “active” regions, full of strong magnetic fields.

Mike Hartinger: You can also see these arcs of plasma shooting out from the sun, they look like little loops…And you see bubbling plasma coming up to the surface, and bubbling up and going back down, kind of circulating…

[SFX: Rumbling solar wind turbulence magnetometer data sonification]

HOST PADI BOYD: These sunspots are the launchpads for dramatic outbursts of radiation and plasma called solar flares and coronal mass ejections. When things on those active regions get too hectic … big loops of plasma can stretch away from the sun and break loose from its magnetic fields … flying off into space.

[SFX: Explosive coronal mass ejection sonification]

Mike Hartinger: So the Sun is dynamic. It’s constantly kind of blasting out plasma at different speeds and this plasma kind of just expands out away from the sun into what we call the solar wind.

HOST PADI BOYD: On Earth, we live in that solar wind… in the atmosphere of our sun. We’re constantly being hit by a blowing stream of particles, moving at a million miles an hour! Luckily, we have a shield here on Earth, one that protects us from the relentless solar wind… and the sporadic explosions of radiation and plasma that come our way from solar flares and coronal mass ejections. And that shield… comes from deep within our planet.

[SFX: Solar wind rumble sonification]

Mike Hartinger: So the Earth has a magnetic field, generated in the core of the Earth, the liquid metal core. And basically from the circulation in that core you get a magnetic field that kind of looks like a bar magnet…

HOST PADI BOYD: If your eyes could see magnetic fields, when you looked at a bar magnet you’d see lines coming out of the top, or north, end and looping around down to the bottom, or south, end. Earth’s magnetic field looks the same… those lines are just coming out of the South Pole, looping out around through space and going back into the North Pole. Earth’s magnetic field is why compasses always point North. But it also has a more important role… it extends way out into space until it meets and matches the solar wind coming from the sun… pushing back against it like a cosmic arm wrestling match.

[SFX: Whooshing sonification of Earth’s magnetic field rebounding from a solar storm from Martin Archer at University College London]

Mike Hartinger: So you got the solar wind, which has plasma and magnetic field in it, and it pushes against the Earth’s magnetic field and plasma, and there’s a balance that gets achieved. The region that we call dominated by the Earth’s magnetic field, we call it the magnetosphere.

HOST PADI BOYD: The magnetosphere is an action-packed space. It’s constantly shifting and changing as its magnetic field lines are compressed by the force of the solar wind and explosions of plasma.

Mike Hartinger: I would say that the solar wind is always changing, it’s always kind of tickling the Earth’s outer boundary in different ways, you know, vibrating it, tickling it just a little bit, but it’s staying more or less that equilibrium. But then yeah if you have that solar wind with a big structure like a coronal mass ejection, it’s like a punch or a big push.

HOST PADI BOYD: That all means that what looks like empty space is actually a busy, bustling place full of activity…

Mike Hartinger: Space is not empty. It’s full of charged particles and magnetic fields that are plasma. If you look up in the night sky, you know, as you get up maybe 100 miles in altitude, you start getting lots of this plasma, and it’s constantly moving around, it’s constantly vibrating, different types of plasma are constantly interacting with each other. And so all these dynamics, or all these behaviors create what I would call a soundscape.

HOST PADI BOYD: You may have heard that in space, no one can hear you scream. That’s definitely true.

Mike Hartinger: You know, if you went out into space, and you were an astronaut, and you took your space helmet off, that would be a terrible idea, but you also wouldn’t hear anything.

[SFX: Honking cars, chirping birds, plucked guitar string, vibrating metal pole]

HOST PADI BOYD: That’s because here on Earth what you hear as sound… city traffic, chirping birds, a plucked guitar string… are actually waves of air pressure vibrating your eardrums. Space doesn’t have any air, and the pressure’s way too low to hear sounds like we do here on Earth. So, what Mike’s saying about a soundscape in space might sound a bit wild. But in the sun’s atmosphere of low-density plasma, other sorts of waves can still travel… plasma waves with electric and magnetic fields we can detect.

HOST PADI BOYD: You definitely couldn’t hear those plasma waves in the same way that you hear sounds on Earth… your eardrum can’t detect electric and magnetic fields. But these waves behave a lot like the sound waves we’re familiar with.

Mike Hartinger: In fact, we mathematically we describe them the same way we, very similar way we describe sound waves on the Earth’s surface. You can think of the Earth’s magnetic field, those kind of magnetic field lines on a bar magnet, if they vibrate, they’re kind of like vibrations on a guitar string. So they are a lot like sound waves. We just can’t hear them with our eardrums.

HOST PADI BOYD: When those waves collide with Earth’s magnetic field lines, they cause vibrations called resonances, just like a guitar string wiggling back and forth after you pluck it.

[SFX: Vibrating gong, echoing electric guitar chords]

HOST PADI BOYD: When a NASA spacecraft flies through the same spot, we collect a lot of data that scientists can print out on charts – squiggly lines representing those waves visually. But they can also play them aloud… it’s a process called data sonification. That’s where Robert Alexander comes in.

Robert Alexander: So I take data from the sun and the heliosphere and turn it into sound.

Robert Alexander: If we were to go into an old school recording studio, we would be recording on magnetic tape.

[SFX: Tape recorder clicks on, drum beat, guitar chords]

Robert Alexander: So we’ve got the lead singer of the band, they’re laying down the vocals, you got the bassist, we’ve got the drummer…we’re recording all these instruments on magnetic tape. And then to play it back. We take those magnetic recordings and then turn them into electrical signals, and then use those electrical signals to move a speaker cone.

[SFX: Tape recorder clicks off]

HOST PADI BOYD: To record Earthly sounds, you use a microphone to turn pressure waves into magnetic and electric ones. To listen to space sounds, you can do the opposite! You convert electromagnetic waves to pressure waves we can hear.

Robert Alexander: Out there in space all the time, we have satellites that are gathering magnetic measurements from the sun in the heliosphere. So, I like to think of satellites as kind of like the most expensive fancy recording studios that are floating out there in space, basking in all these rich datasets gathering the greatest hits of the sun. And for me, I think of NASA’s data archive like an old dusty record collection.

HOST PADI BOYD: Ten years ago, Robert teamed up with NASA’s Goddard Space Flight Center and scientists at the University of Michigan to do just that… dig into the data, pull out the records, and help scientists listen to the music of the sun.

Robert Alexander: When I first started working with the solar heliospheric research group, I walked in the room, and they would put plots up, and they’d have these massive spikes in things like the velocity of the solar winds, and they would get so excited and so geeked at these plots, but for me, I didn’t have the same background that they had. So for me, sonification was a really helpful tool to be able to translate their enthusiasm from their domain into this more universal language that I was able to understand.

HOST PADI BOYD: Robert’s a scientist, but he’s also a composer. So he started by listening to the sun as an instrument… and exploring it through music.

[MUSIC: Robert Alexander’s musical sonification, version 2.1]

HOST PADI BOYD: In the sonification you’re hearing, the whooshing is generated by changes in the solar wind’s velocity, and the layers of voices represent changes in temperature.

HOST PADI BOYD: When it gets hotter, the voices get higher in pitch. And can you pick out the explosions? When a coronal mass ejection, or CME, happens in the data, everything gets louder!

HOST PADI BOYD: That’s a lot of information packed into music.

HOST PADI BOYD: And then the research team posed a challenge… they asked Robert if he could listen closely enough to the sun to discover something totally new.

Robert Alexander: And in a moment of inspiration, I thought “What if I take these data streams and I write it directly to an audio file?” And I remember, I was sitting at a coffee shop, the first time that I listened to this.

[SFX: Cacophonous whooshing rumble of turbulent solar data filters down to low hum]

HOST PADI BOYD: The sun is really turbulent. So to find order in the audio chaos, Robert first had to filter out some of the background noise. Once he did, he heard a pattern… a hum.

Robert Alexander: So I’m listening to data, and I was sure that I made some mistake in my calculations, because I kept hearing this noise in every one of my files. And I was like, “Aw man, I got the numbers wrong, I gotta go back and do all this again.” And as I continued listening, I thought to myself, “What if this is actually a feature in the data rather than some kind of error in my calculation?” So I went back and I crunched some of the numbers. And it turned out that the hum that I was hearing was exactly correlated with the solar rotational period, which is around 26.5 or 27 days. And so what I was hearing was the rotation of the sun.

[SFX: Low rumble of filtered solar rotational data]

Robert Alexander: I remember I messaged my friend, I had a message window up, and I was like, “Oh my gosh, I’m hearing the sun rotating!”

Robert Alexander: So there we were listening to 60 years’ worth of solar rotational data. And the rise and fall of that hum correlates with the rise and fall of solar activity with what’s called the solar cycle.

HOST PADI BOYD: Right now, we’re nearing the peak of the solar cycle, and seeing more and more sunspots, solar flares and coronal mass ejections. In the data, Robert realized he could hear those features on the sun disappearing and reappearing as the sun rotated.

Robert Alexander: When we have just one feature that rotates around on the sun, we get the fundamental frequency which is that 27-day rotational period…

HOST PADI BOYD: Then Robert started to hear something else in addition to that fundamental frequency sound, as more sunspots and activity appeared. Something that sounded a lot to the trained composer like music…

Robert Alexander: I realized not only can I hear the rotation of the sun, but I can hear harmonics above this fundamental frequency.

HOST PADI BOYD: Listen closely. Do you hear the solar wind’s music?

[SFX: Low rumble of solar data]

Robert Alexander: When we get two regions that rotate together on opposite sides of the sun, we get an octave above that fundamental frequency.

[SFX: Robert harmonizes with first octave in solar data]

Robert Alexander: If we have three regions … They’re now, if you kind of visualize it, they’re equally spaced in thirds around the sun. And this creates an octave and a fifth.

[SFX: Additional layers of Robert’s voice harmonizing with the rumble]

Robert Alexander: And above that, we get two octaves. And then we get the major third and then the fifth. This creates these musical harmonic components in the solar wind.

[SFX: Host Padi Boyd harmonizes with Robert]

Robert Alexander: When you listen closely to the audio you get this [hums along]. And then depending on how much of the turbulent noise you filter out, you can hear the [hums along at higher pitch] higher order harmonics…

Robert Alexander: I go back and I take these results and I show them to the research group, and they’re like, “Oh yeah, of course there are harmonics, it’s a part of the way the magnetic field superimposes itself over the sun and that heads out and into the solar wind, and still, just, my mind was blown. Like, “You can hear the harmonic series and solar data, it’s crazy!”

HOST PADI BOYD: Robert had started out by trying to turn the sun’s sounds into music… but it turns out the sun makes music of its own! And while listening to the sun’s harmonics, turning the solar data into sound, Robert and his team made a new discovery about the solar wind that scientists had never seen by simply looking at the data. By measuring the strength of these harmonics across elements like oxygen and carbon, they produced the most sensitive diagnostic of the electron temperature of the solar wind ever recorded.

Robert Alexander: And there I got the rush, you know, the adrenaline rush of the realization that we can listen to sounds from the sun and make new scientific discoveries that expand our understanding of the sun and of the heliosphere.

[MUSIC: Curiosity by SYSTEM Sounds]

But this was just the beginning. Soon after, Robert and Mike launched a project where everyday people could help study solar wind and the Earth’s magnetic field. And to find the hidden patterns in that data, they needed something way more powerful than algorithms or AI… human ears.

That’s coming up, after the break.

MIDROLL

[MUSIC: Curiosity by SYSTEM Sounds]

HOST PADI BOYD: If you could listen to a star, what would you hear? Robert Alexander and other NASA experts are doing just that… listening to our sun to learn its secrets, through a process called data sonification. Heliophysicists are used to reading charts and looking at stunning images from spacecraft. But more recently, they’ve discovered that by closing your eyes and trusting your ears, you can discover things you never could have seen.

HOST PADI BOYD: Today, Robert’s part of a new NASA citizen science project, alongside heliophysicist Mike Hartinger, trying to make new discoveries by listening to the sun… It’s called HARP, short for Heliophysics Audified: Resonances in Plasmas.

Mike Hartinger: So we love acronyms in heliophysics. Scientists just love acronyms, right? So you know our acronym is HARP.

[MUSIC: Shores of Eventide underscore by Benjamin Peter McAvoy]

Mike Hartinger: And we’re studying basically a massive magnetic harp in outer space, where if you look at the Earth’s magnetic field, you can kind of look at it in from the perspective of a harp, where the harp strings are short, close to the Earth, because the Earth’s magnetic field lines are short. And if you move away from the Earth, these magnetic field lines or magnetic strings get longer and longer. And the analogy is really pretty exact, because you definitely hear the pitches of these waves get lower and lower as you move away from the Earth.

HOST PADI BOYD: To study Earth’s magnetic harp, the team is using data from a satellite called THEMIS.

[SFX: NASA broadcast of THEMIS launch: “And liftoff of a Delta 2 rocket carrying THEMIS, NASA’s revolutionary journey to study the northern lights”]

Mike Hartinger: It looks kind of like a box. And it’s this box that’s spinning. It’s got all these sensors, and it’s measuring magnetic fields as it’s going all the way around on its orbit.

HOST PADI BOYD: As the THEMIS satellite orbits Earth, it flies through the different strings of Earth’s magnetic field… picking up the resonances the solar wind creates when it hits them and plays them… like plucking a harp string.

Mike Hartinger: To study a harp, you need to basically pluck all the different strings.

HOST PADI BOYD: Luckily, THEMIS is set up to do that. It has an elliptical orbit, sort of an oval shape path it takes around the Earth.

Mike Hartinger: And that’s good for us because we wanna study this harp. An elliptical orbit, you can basically run across the whole harp and hear all those different pitches, all those different strings. And what you’ll see then is as the satellite moves away from the Earth on its orbit, you’ll hear a descending tone.

[SFX: Descending gurgling tone of HARP sound]

Mike Hartinger: And then as it gets back and moves back towards the Earth, you’ll hear the tone come up in pitch.

[SFX: Ascending gurgling tone of HARP sound]

Mike Hartinger: And it’s kind of going back and forth along the harp.

[SFX: Full HARP sound with harp strumming in the background]

HOST PADI BOYD: That’s a perfect, ideal HARP sound.

Mike Hartinger: Of course, in a real event, you’re going to hear all kinds of different stuff. You’re going to hear on top of that crunches, you’re going to hear all kinds of chirps and other things happening. And that’s part of the why we want to work with volunteers to pick out these really unique patterns that change from day to day.

[MUSIC: “Ciùin” by harpist Ciorstaidh Beaton]

HOST PADI BOYD: The THEMIS satellite has been collecting data for over 15 years. That’s a lot of sun data! But don’t worry, it doesn’t take that long to listen through it as a volunteer! The waves HARP is dealing with are ultra-low frequency, like most waves from the sun. Which means they’re so low in pitch that you can’t hear them normally. The team speeds them up so they’re in the frequency range your ears can hear, which has the added benefit of letting you listen through hours, even days of data in seconds!

Mike Hartinger: You know, we have a lot of research that’s been done. Individual scientists over the years and groups of scientists have learned a lot about these waves. We’ve learned about the types of instruments that are in this kind of symphony in the near-space environment. We’ve learned there are things like the harp, these magnetic strings, or guitar strings.

[SFX: HARP sound]

Mike Hartinger: We’ve learned there are things like a drum, like that outer boundary that the solar wind is pushing on is kind of like a drum, like that outer boundary that the solar wind is pushing on is kind of like a drum, you can tap on it and you’ll play different pitches or different types of pitches.

[SFX: Thumping drum sound of Earth’s magnetic field recorded by THEMIS]

HOST PADI BOYD: Scientists have identified many of the different instruments in the solar symphony, but they don’t yet understand its music… all the different combinations the symphony can play in… the patterns in pitches and amplitudes and intensities that can tell us so much about the solar wind and magnetosphere…

Mike Hartinger: There are all these patterns that are there, that, if someone just listens to the data they pick out right away, you know. You listen to a year’s worth of data, you’ll ultimately find these complex but repeatable patterns in the sound that you wouldn’t have known to look for if you just looked through visually. So that’s why we need people’s help. They can go through a lot of data fast. Getting more people’s ears on the data and the eyes on the data too, because you can also see the data on our website. So the more people that can look at this the better.

HOST PADI BOYD: Your ears and eyes are a lot better than computers at finding patterns in HARP data. Citizen scientists listening to HARP sounds have already made a new discovery – a unique “reverse harp” sound that researchers didn’t expect at all. Can you hear the difference?

[SFX: Gurgling reverse HARP sound]

HOST PADI BOYD: Sonification has also revealed a new sound in the solar wind and magnetosphere data that’s not harp-like at all… but one that may sound familiar. Here’s Robert again.

Robert Alexander: A lot of features in the solar wind sound like chirping birds, there is an analysis example from the THEMIS satellite, where there were these big features in the spectral plot. And there’s this tiny little feature up top that wasn’t really visually interesting, but when we played it back, we heard this kind of chirping bird sound.

[SFX: Chirping sound in THEMIS data]

Robert Alexander: So we hear that kind of whir.

[SFX: Chirping sound in THEMIS data]

HOST PADI BOYD: That sound turned out to be several types of wave superimposed in the magnetosphere… a rare find. It’s a lot harder to pick that phenomena out by looking at a chart.

Robert Alexander: And the reason why it stuck out in auditory analysis was because it was just acoustically interesting. Like you don’t expect to hear a bird chirp in the middle of your magnetometer data, your electric fields data. So that tells us that there’s something unique that’s going on.

HOST PADI BOYD: As human observers of the universe, we can use our senses together, sight and sound, to better understand our lifegiving star and the space beyond.

Mike Hartinger: One thing I always tell people about this is, you know, magnetic and electric fields and the stuff that we study is invisible. And it’s equally valid to use sound as to use visual, I mean, we use visual representations of things like graphs with, like wiggly lines. But it’s arbitrary, right? Like, there’s no reason you have to, you know, interact with that data visually, you can totally do it with sound and there’s, it’s an equally valid way of interacting with it. And in fact, you see different patterns with both of those.

Mike Hartinger: If you go outside any given day, and you close your eyes and just listen to what the birds are doing…

[SFX: Creaky door opens, footsteps on stairs, chirping birds, hawk calls]

Mike Hartinger: Without even opening your eyes, you can tell what’s going on, you can tell if there’s a hawk that just flew by, you can tell if there is a nest nearby, you can tell if a human is walking by. I mean, and I think it’s the same with space sounds you can learn so much about the environment, just by listening to the sounds through a speaker.

[MUSIC: When Light Comes underscore by Benjamin Peter McAvoy]

HOST PADI BOYD: The more tools we have at our disposal to study waves in space, the more accessible science becomes… better including scientists and citizen scientists who have limited vision or hearing. Science, like space, is for everyone!

Robert Alexander: When we use our eyes, we can pick up certain things from a plot or a graph. For a lot of people, they see a graph and it just kind of shuts them off….When we listen to an audio file, it tends to pique our curiosity. And we can pick out a whole slew of other details, we can hear that glistening high frequencies and rumbling low frequencies. When we get out of bed in the morning, we don’t decide, “Am I going to use my eyes or my ears today?”

Robert Alexander: We live in this multisensory world. And by turning data into sound, we’re just using a sense that’s more optimized for frequency analysis to conduct frequency analysis.

Robert Alexander: I think it’s incredibly important that human beings have this very intimate connection with the data that’s gathered by satellites. And just like stethoscopes allowed doctors to hear the human heart, we now have these satellites that allow us to listen to the heartbeat of the sun. And I think so much of the investigation that takes place is driven by human intuition. And our human intuition can be an invaluable tool when it comes to the process of scientific research.

[SFX: Rumbling sonification]

[MUSIC: Henry Dehlinger’s Cosmic Cycles, The Sun]

Child 1: The Sun sounds like a lot of different things. Like, um, really low buzzing. Kind of like when you’re like, lifting off on the plane? Or like, when a jet’s taking off?

Child 2: Or maybe it sounds like, um, a lot of rain falling down?

Child 1: It sounds kind of like, a lot like fire.

Child 2: Um, maybe fire? Or birds, flying?

Child 1: Like if you turn your head a certain way or stick it out of a window and the wind goes in it, it sounds kind of like that too.

Child 2: Sandstorm!

Robert Alexander: I think you guys are all right. So it sounds like a rain-filled fiery sandstorm? Right?

Child 2: With a stampede of elephants!

[SFX: Hand drumroll on table]

Robert Alexander: So the stampede’s coming and here comes the sandstorm…

[SFX: Whooshing sound made by kids]

Robert Alexander: And then we have the hum of the wind… and then the rain! Wow, thank you guys!

[Theme Song: Curiosity by SYSTEM Sounds]

That story came from NASA’s Curious Universe, an official NASA podcast that takes you on mind-blowing adventures in science and space. In one episode, they explore how the Clipper probe will search for signs of life on Jupiter’s icy moon, Europa. In another, they unravel the mystery of a strange space rock with Radiolab’s Latif Nasser. Subscribe to NASA’s Curious Universe right here in your podcast player.

Twenty Thousand Hertz is produced out of the sound design studios of Defacto Sound. Hear more at Defacto Sound dot com.

HOST PADI BOYD: This episode was written and produced by Christian Elliott. Our executive producer is Katie Konans. The Curious Universe team includes Jacob Pinter, Maddie Olson and Micheala Sosby.

HOST PADI BOYD: Our theme song was composed by Matt Russo and Andrew Santaguida of SYSTEM Sounds. Special thanks to Alessandra Pacini at NOAA, Denise Hill and the NASA heliophysics team, all the HARP project volunteers who sent us voice memos, Ciorstaidh Beaton for her harp music for the HARP project, Henry Dehlinger for the use of his Cosmic Cycles symphony, and scientists at the British Antarctic Survey and the University of Iowa’s space physics department studying space weather for the whistler and chorus wave sounds.

I’m Dallas Taylor. Thanks for listening.

[SFX: HARP sounds]

Adult 1: It sounds like robot frogs talking to each other underwater.

Adult 2: Zippers, zippers underwater, just very fast.

[SFX: HARP sounds]

Child 1: Gurgly!

Robert Alexander: Wait what does gurgly sound like?

Child 1: It sounds like, here, if you get me some water I can show you!

Child 2: I can do it! Three glasses of water!

Child 1: Take a breath before you do it, okay?

[SFX: Kids gargle water to create HARP sound]

Child 1: All over my socks!