The Sound Barrier #4: Listen to the universe

When Wanda Diáz-Merced lost her sight as a college student, she thought her dreams of becoming an astronomer were over — until she learned to listen to space instead. Wanda is one of several pioneering scientists listening to space. For this episode, we also spoke to Robert Wilson, who used sound to help him discover the first direct evidence of the Big Bang, and Kim Arcand, who plays us what the center of the Milky Way sounds like. This is the fourth episode in our of our new four-part series, ⁠⁠The Sound Barrier⁠⁠. Guests: ⁠Wanda Diáz-Merced⁠, astronomer; ⁠Robert Wilson⁠, Nobel laureate and senior scientist at at the Harvard-Smithsonian Center for Astrophysics; ⁠Kim Arcand⁠, emerging tech lead at NASA's Chandra X-ray Observatory You can find Kim’s sonification of the center of the Milky Way (with visuals) here: ⁠https://chandra.si.edu/sound/gcenter.html⁠ For show transcripts, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unxtranscripts⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ For more, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unexplainable⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ And please email us! ⁠⁠⁠⁠[email protected]⁠⁠⁠⁠ We read every email. Support Unexplainable (and get ad-free episodes) by becoming a Vox Member today: ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/members⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ Thank you! Learn more about your ad choices. Visit podcastchoices.com/adchoices

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Speaker 00

  Support for the show comes from TikTok. If you listen to this show, you probably enjoy discovering new things. It is built into the DNA of the show that curiosity is its own reward and that there's always a deeper dive to do. And one place to explore some of the topics we've covered here is TikTok. Whether it's how to forecast volcanic eruptions, strange phenomena that the James Webb Space Telescope picked up near the beginning of time, or a literal deep dive on the ocean's deepest reefs, TikTok has a wealth of fascinating videos just waiting to be discovered. Your next discovery is waiting on TikTok. Learn more at tiktok.com/discovermore.

• 0:48Speaker 01

  In the world of expense management, SAP Concur is here to help. From cost control slipping to travel chaos, SAP Concur has an integrated travel and expense solution to help you overcome problems like overburdened teams, decisions looming. When travel, expense, and AP are connected with a single AI-supported solution, SAP Concur keeps you ahead of problems. Visit concur.com to learn more.

• 1:22Noam Hassenfeld?

  Hello, can you hear me?

• 1:24Speaker 03

  Ay, caramba.

• 1:26Noam Hassenfeld?

  Juanda Diaz-Merced can make pretty much anything seem special.

• 1:31Speaker 03

  Can you say one, two, three?

• 1:33Noam Hassenfeld?

  Like, when I first called her up and we were working through some connection issues. One, two, three.

• 1:37Speaker 03

  Oh, this is very good. You say one, two, three beautifully.

• 1:40Noam Hassenfeld?

  Oh, thanks so much. Or the way she talks about Star Trek.

• 1:43Speaker 03

  It's awesome, right? It's the best thing that has ever happened. See?

• 1:49Noam Hassenfeld?

  She really loves Star Trek.

• 1:51Speaker 03

  You cannot miss that.

• 1:53Noam Hassenfeld?

  And Juanda's always been like this, ever since she was a kid.

• 1:57Speaker 03

  I do remember that my sister was bed-bound for a very long time. And at that time, the movable bed that she had, it had some steel tubes on the side. And she had a cast that would go from below her neck to covering the two legs. So to me, she was an astronaut.

• 2:24Speaker 03

  In a spacecraft. And we would play many, many, many times like being astronauts.

• 2:36Noam Hassenfeld?

  Wanda didn't have an easy childhood. She grew up in Gurabo, this small city just outside of Caguas in Puerto Rico. Her family didn't have a lot of money or education. Her sister was chronically ill. Wanda was diagnosed with diabetes when she was just 10. And even though she played astronaut, she never considered studying space. Until one day, she was out fishing with her dad and she looked up.

• 3:04Speaker 03

  I remember clearly three beams of a meteor. One was reddish, the other ones were more towards the bluish side. And I remember that it lasted like less than a second. And I, I made this expression like, oh, you know, like to me, that was like, oh, it has been like the greatest thing. And my father, he turned toward me and he said, those are rocks falling from the sky. And what he was telling me is that's not a spiritual thing. There is science behind it.

• 3:46Speaker 03

  Those are rocks falling from the sky. So at that moment, it's like, I need to learn more about those rocks. Where are they coming from?

• 3:59Noam Hassenfeld?

  Wanda eventually went to college to study science. But by this point, her diabetes had gotten worse and she was starting to lose her vision.

• 4:09Speaker 03

  No, there is a problem. And he said, if you cannot read, your grades will be very, very, very bad.

• 4:16Noam Hassenfeld?

  Right.

• 4:17Speaker 03

  And if you have no one reading to you, your grades will be worst. So I would intuitively guess answers.

• 4:27Noam Hassenfeld?

  She thought about trying to study something else.

• 4:29Speaker 03

  But I didn't have the minimum GPA to transfer to another faculty. So I had to stay in science and thinking, what am I going to do in the field of science? I cannot see.

• 4:43Speaker 03

  And I cannot change. And then I'm blind and I have a disability. But also, I'm the only one that can work in my family.

• 4:53Noam Hassenfeld?

  Her father had lost his job. Her sister was still sick. It was a lot of pressure for a 22-year-old.

• 5:00Speaker 03

  I cannot leave the university because it's going to be a major family situation.

• 5:08Noam Hassenfeld?

  Wanda hadn't really come to terms with the fact that she was going blind. She kept hoping that one day she'd just wake up and suddenly be able to see again. So she didn't really talk about it. And she only had one friend who noticed.

• 5:23Speaker 03

  He was the only one who knew something was happening to me. Because I would sit and would not move unless I would perceive that no one else was in the hallway.

• 5:35Noam Hassenfeld?

  Her friend, Emilio, happened to be the president of the astronomy club. And when he saw how much Wanda was struggling, he had an idea.

• 5:43Speaker 03

  He said, "Wandita, I want you to come with me. And I want you to listen to what I have in my house."

• 5:49Noam Hassenfeld?

  Emilio showed her this small antenna he had in the back of his house. Basically, just two hanging metal wires. He handed her a pair of headphones, and she listened.

• 6:02Speaker 03

  It was a noise, white noise, right? And then it increases, right? And then it diminishes. It may have lasted about 30 seconds. And I said, "Emilio, turn that off. It's horrible."

• 6:23Noam Hassenfeld?

  But Emilio didn't turn it off. He kept playing it. This is a recording of the actual sound they were listening to, by the way.

• 6:32Noam Hassenfeld?

  And finally, he told her what it was.

• 6:35Speaker 03

  He said, "Wanda, I think that it's a sunburst. It was a real-time detection of a solar emission."

• 6:44Noam Hassenfeld?

  Wanda was literally hearing the sun. And as luck would have it, she was tuning into one of the most powerful solar storms ever recorded. She was hearing the sun's outer atmosphere being blown off into space.

• 7:02Speaker 03

  And at that moment, everything transformed. From me perceiving that those sounds were bothersome and ugly, it transformed into beauty. Even more, the sense of possibility, right? My world was closing up bit by bit. Honestly speaking, at that very moment, I was dying. And that death sentence begun to lift up. You have no idea. For the first time, I felt happiness in my life.

• 7:44Noam Hassenfeld?

  It was like she was a kid again, coming face to face with the sky. And she realized she wouldn't have to give up on her dream. She could still study space. She'd just have to listen to it instead.

• 7:59Speaker 03

  When you listen to it, it's not a cold, not moving space. It's very, very active. It's full of dynamism. It's full of life.

• 8:20Noam Hassenfeld?

  I'm Noam Hassenfeld, and this is the final episode of The Sound Barrier, a series from Unexplainable about the limits of our senses and the ways we can break through. On today's episode, what are we missing when we just look out into space? And what can we learn if we listen?

• 8:59Noam Hassenfeld?

  If you've only ever heard one thing about space and sound, it might be from the movie Alien.

• 9:05Speaker 04

  There's gotta be a way of killing it. How? How do we do it?

• 9:09Noam Hassenfeld?

  It was on the poster, it was in the trailers. You can't. In space, no one can hear you scream.

• 9:19Noam Hassenfeld?

  It's a pretty great tagline, but it's also scientifically accurate.

• 9:24Speaker 03

  Sound as we know it here on Earth, it needs air, it needs a means of propagation to be detected by an ear.

• 9:32Noam Hassenfeld?

  Sound is a pressure wave. It's basically just a vibration, which means it needs something to move through. It could be air, it could be water, it could be the ground. So when someone is talking to you in a room, they're literally making the air vibrate, which makes your eardrum vibrate, which your brain hears as sound. But space

• 9:56Noam Hassenfeld?

  is almost a complete vacuum, which is why it's pretty much silent.

• 10:04Noam Hassenfeld?

  But there are other kinds of waves that can move through space: visible light, X-rays, gamma rays. And some of them, like radio waves and microwaves, can be picked up by antennas and shifted down into our hearing range.

• 10:18Speaker 03

  You have an electronic device in the receiver that brings it into the frequency of human hearing.

• 10:28Noam Hassenfeld?

  That's what Wanda was hearing in her friend's backyard: radio waves, shooting out from the sun, picked up by the antenna, shifted down so she could listen.

• 10:44Noam Hassenfeld?

  Wanda was so blown away by what she heard out there that she wanted to learn everything she could about listening to space. But she still had to deal with all the limitations of her life on Earth.

• 10:55Speaker 03

  Remember, I couldn't read the books. Screen readers were not available. So I was asking people, sitting in the library, can you find on the computer this or that or whatsoever? And whatever search engine that was available would bring this information to us.

• 11:12Noam Hassenfeld?

  But she learned that scientists had been listening to space for decades. Like the engineer who was able to listen to the center of the Milky Way, or the physicist who listened to plasma waves, these ripples through charged particles in space, or the scientist who used sound to help him make one of the biggest scientific discoveries of the 20th century.

• 11:32Speaker 05

  I didn't realize at the time how big it was, but I do now.

• 11:37Noam Hassenfeld?

  That's Robert Wilson.

• 11:38Speaker 05

  Usually known as Bob.

• 11:40Speaker 03

  You spoke to him.

• 11:41Noam Hassenfeld?

  Wanda was pretty pumped.

• 11:43Speaker 03

  Ah!

• 11:45Noam Hassenfeld?

  Bob is extremely chill about the whole thing.

• 11:48Speaker 05

  We weren't even so impressed with cosmology.

• 11:51Noam Hassenfeld?

  Bob's almost 90 now, and he hasn't stopped. He's a senior scientist at the Harvard Smithsonian Center for Astrophysics, and he's one of the first names Wanda came across when she was diving into the history of listening to space. Because Bob and his partner used sound to help them find the first direct evidence of the Big Bang, and it happened by accident. Back in the 60s, Bob was pretty different.

• 12:19Speaker 05

  Well, I had hair.

• 12:21Noam Hassenfeld?

  Still, just as understated. And he was a young physicist working with his partner on a new antenna, trying to measure microwaves from outside the Milky Way. But when they went to make their first measurement, they noticed this problem.

• 12:35Speaker 05

  There was this booming signal. The antenna was twice as hot as it was supposed to be.

• 12:42Noam Hassenfeld?

  When Bob put on his headphones, it sounded like some kind of static.

• 12:46Speaker 05

  If you had a television and you turned to an off channel, you would get a hiss.

• 12:51Noam Hassenfeld?

  Yeah, like the snow?

• 12:53Speaker 05

  Yeah, same effect. We were very disappointed at that point and started thinking about what could be wrong.

• 13:00Noam Hassenfeld?

  They kept listening to the sound to make sure it wasn't just noise from somewhere nearby, like the city. But no matter which direction they pointed the antenna, they still heard the hiss.

• 13:11Speaker 05

  So that couldn't be it.

• 13:12Noam Hassenfeld?

  They thought it might be radiation from a nuclear weapons test. So they waited a few months, measured again, still had that hiss.

• 13:20Speaker 05

  Nothing had changed.

• 13:21Noam Hassenfeld?

  They even thought it might be something, let's just say, closer to home.

• 13:27Speaker 05

  There was a pair of pigeons that lived in the antenna.

• 13:30Noam Hassenfeld?

  There are pigeons that lived in the antenna?

• 13:33Speaker 05

  Yes.

• 13:34Noam Hassenfeld?

  Okay.

• 13:34Speaker 05

  We'd see them flying in and out. So we put a little bait in there, caught the pigeons, but none of that made any difference.

• 13:42Noam Hassenfeld?

  So even after the pigeons were gone, you still heard the hiss?

• 13:45Speaker 05

  Right.

• 13:47Noam Hassenfeld?

  Bob still wasn't anywhere close to thinking about the Big Bang. He was still thinking about those freaking pigeons.

• 13:54Speaker 05

  They had deposited pigeon dropping into the antenna.

• 13:58Noam Hassenfeld?

  There was poop in the antenna?

• 13:59Speaker 05

  Well, they'd been living in there. What do you expect?

• 14:02Noam Hassenfeld?

  Okay.

• 14:02Speaker 05

  We just scrubbed it out. It wasn't a big deal.

• 14:07Noam Hassenfeld?

  Bob didn't really spend too much time pondering the origins of the universe. He figured it had just always been there.

• 14:14Speaker 05

  The idea that it's the same now as it was before and will be the same in the future.

• 14:20Noam Hassenfeld?

  That's what most people thought at that point. But there was this other idea that was starting to gain some traction. The Big Bang, that the universe started in this gigantic explosion. But Big Bang believers were still looking for their smoking gun.

• 14:35Speaker 05

  The expectation was if the universe started out very hot and full of radiation, it would still be full of radiation. There would be something left over from the initial explosion, which one could detect.

• 14:52Noam Hassenfeld?

  Bob started telling other scientists about the hiss. And when the Big Bang Brigade finally heard about it, they were like, Bob, you found it. That hiss, which is all over the place, all the time, and is definitely not pigeons. That's the leftover radiation from the Big Bang.

• 15:09Noam Hassenfeld?

  When you found out that what you had been noticing for nine months could I don't even know how to say this, like, could be the the the answer to the origin of the universe, like, what did you feel?

• 15:26Speaker 05

  I think we felt that, uh, yes, that's a possibility. Maybe there's some other explanation.

• 15:34Noam Hassenfeld?

  You just weren't that, you weren't that excited?

• 15:37Speaker 05

  Not terribly excited. We weren't quite ready to say that that's the only possibility.

• 15:46Noam Hassenfeld?

  About a year later, after a bunch of follow up research, Bob got a call from a reporter at the New York Times. And finally, he started to buy into the hype.

• 15:56Speaker 05

  The next morning, my father walked down to the local pharmacy and bought a New York Times. And there on the front page of the New York Times was a picture of the Anta and an article about this discovery.

• 16:11Noam Hassenfeld?

  Written on top of that picture was the headline, Signals imply a Big Bang universe.

• 16:20Noam Hassenfeld?

  By the time Wando was learning about Bob's story, the Big Bang had become something astronomers and really lots of people just took for granted. Of course, the universe had a beginning. Of course, it was this really big explosion. But every fact that seems like bedrock truth once had a beginning, where it shifted from a wacky idea to something we all just accept. And for the Big Bang, that moment was when Bob and his partner noticed this signal.

• 16:53Noam Hassenfeld?

  This is the actual sound they heard when they put on their headphones.

• 16:58Noam Hassenfeld?

  A lot of it's just static from the instruments. But a good amount of it, like 10%, is the leftover radiation from the Big Bang. It's the sound of the creation of the universe.

• 17:14Noam Hassenfeld?

  Bob and his partner eventually won a Nobel Prize for their work. And they created a precedent for Wanda to follow. That sound can play an essential role in some of the biggest scientific discoveries in history. So you can see why Wanda would kind of freak out when I brought up Bob.

• 17:31Speaker 03

  No, I'm so moved that you spoke to Wilson. Well done.

• 17:37Noam Hassenfeld?

  But Bob was only listening to a small slice of the universe. Microwaves that were shifted into our hearing range. In a minute, Wanda learns how to listen to everything else.

• 17:54Noam Hassenfeld?

  Support for the show comes from Sonos. Hey, Sonos, give me some music.

• 18:00Noam Hassenfeld?

  All right. One of life's great mysteries. You're listening to music in the living room, but you gotta grab something from the kitchen. You don't want to take the speaker with you, but you also don't want to miss that beat drop. And this is where I introduce you to the magic of Sonos. Sonos sent me a couple of speakers to try out, so I've got a Move 2 here in the living room. And then I walk down the hall. I get in here to the kitchen, and I got a brand new Sonos Play right here on the counter. I can open the fridge, grab a seltzer.

• 18:43Noam Hassenfeld?

  And yeah, I didn't miss a second. And I can make each speaker louder or softer in the Sonos app, or if I'm using AirPlay, so I can make it louder in the kitchen without blasting whoever is still in the living room. It's all just easy, and it sounds amazing. These speakers are crisp, they've got great bass, and I'm especially impressed with the new Sonos Play. It packs this truly awesome sound in a much smaller size. So I don't know, if I want to head outside for a minute. It's super easy and, yeah, pretty nice out. Visit sonos.com and build your system.

• 19:26Noam Hassenfeld?

  Sonos, love the sound, feel the system.

• 19:34Speaker 00

  Support for the show comes from TikTok. Being curious is endlessly rewarding. There are few better feelings, in my opinion, than asking a question and then having that question lead you down a rabbit hole. Might even be the beginning of a new set of interests that was not on your radar beforehand. Maybe you're looking up at the night sky one night and you start to wonder what the most distant thing you can see with the naked eye is. One place to start searching for answers to a question like that is TikTok. First, you might discover a video about the Andromeda Galaxy. And then, next thing you know, you're learning how to find different stars, or how to identify

• 20:17Speaker 00

  constellations, or how different astronomical discoveries got made, or how constellations got their names. You don't need serious equipment to make serious discoveries. Start with a simple question, and suddenly, you're somewhere you never expected to be. Your next discovery is waiting on TikTok. Learn more at tiktok.com/discovermore. At tiktok.com/discovermore.

• 20:49Speaker 01

  In the world of expense management, SAP Concur is here to help. From cost control slipping to travel chaos, SAP Concur has an integrated travel and expense solution to help you overcome problems like overburdened teams, decisions looming. When travel, expense, and AP are connected with a single AI-supported solution, SAP Concur keeps you ahead of problems. Visit concur.com to learn more.

• 21:27Noam Hassenfeld?

  A few years after Wanda started learning about listening to space, she found herself at NASA. She couldn't believe how she pulled it off, but she got an internship.

• 21:37Speaker 03

  That was a huge blessing because my grades were very, very, very, very, very, very, very bad.

• 21:44Noam Hassenfeld?

  And she wasn't just planning to listen to that tiny slice of the universe, the radio waves, the microwaves. She wanted to hear the meteors she saw as a kid. So she started working on something called sonification.

• 21:58Speaker 03

  Sonification is bringing information into the audible domain in order to augment your perception.

• 22:05Noam Hassenfeld?

  Sonification isn't what Wanda was doing when she heard that sunburst in her friend's backyard, or what Bob was doing when he heard that hiss left over from the Big Bang. They were directly listening to things like radio waves or microwaves that were shifted into the range of human hearing. But sonification is a way to translate any kind of data into sound. You can take things we can see, like stars or galaxies, things we can't see, like X-rays or infrared light, and you can translate them into something we can hear. It's kind of like a Geiger counter, those little handheld gadgets that tell you about radiation levels by playing a bunch of clicks. Those clicks aren't what radiation sounds like. They're just a translation of the data.

• 22:50Noam Hassenfeld?

  They're a way for scientists to hear where the radiation is and how strong it is.

• 22:55Speaker 03

  Audio will increase perception to things that are blind to the human eye.

• 23:02Noam Hassenfeld?

  Sonifications don't need a sound like the Big Bang background fuzz or whooshing sunbursts. They can sound like anything, as long as they're clearly communicating the data. And it's often a lot easier to hear things than it is to see them.

• 23:19Noam Hassenfeld?

  This is a sonification of a mouse walking. I love this example. Every sound you're hearing is a pair of paws hitting the ground. And now, here's a mouse that has a genetic mutation, which makes it wobble when it walks. If you wanted to find out exactly when its paws hit the ground, it would be pretty hard to tell just by looking at it, but it's obvious when you listen.

• 23:46Noam Hassenfeld?

  So Wanda was curious if she could harness this potential for astronomers. And she set up a test.

• 23:53Speaker 03

  I simulated a task that astronomers used for the detection of black holes.

• 23:59Noam Hassenfeld?

  She gave scientists simulated data that looked like what happens when gas swirls around a black hole. There were graphs that showed where the radiation was strongest, and there were sounds that showed the same thing. Some examples were clear, other ones were trickier. And when astronomers used both the graphs and the sounds, they did better than when they just used one or the other. But audio was just about as good as a graph on its own, sometimes even better, which gave Wanda confidence that she could make new discoveries by listening to different parts of space, like the merger of two neutron stars, these ultra-dense remnants of exploded supernovas.

• 24:40Noam Hassenfeld?

  Each hit you're listening to is a measurement of the energy given off by these two stars as they're orbiting each other. Louder hits, more energy. Softer hits, less energy. And Wanda chose to use these high-pitched timpani hits for this sonification so she could hear the tempo changes really clearly.

• 25:00Speaker 03

  If you hear, the changes, the ups and downs are quite uniform, but then at the end, there is an area where it seems the tempo is changing. It feels a little bit faster.

• 25:15Noam Hassenfeld?

  Right there, there's a little hiccup in the tempo.

• 25:18Speaker 03

  And it's telling me about how the system is rotating. It's not as uniform as we think.

• 25:27Noam Hassenfeld?

  She's even used sonification to find things no one had noticed before, like in a gamma ray burst, this huge explosion that happens when a star dies.

• 25:36Speaker 03

  The interior of the star collapses under its own weight, and it starts rotating ever faster, like a ice skater when pulling their arms in close to their body.

• 25:46Noam Hassenfeld?

  Wanda actually gave a TED Talk about this gamma ray burst. She decided to zoom into a part of it that other people might have missed, this part that might have just been confused for noise in the data.

• 25:58Speaker 03

  And I want you to hear what I heard. You will hear it as a very fast decrease in volume.

• 26:07Speaker 03

  There is frogs at home. Don't pay attention to that.

• 26:16Noam Hassenfeld?

  That's the fast decrease in volume she's talking about, right there. It's really subtle. It's also kind of masked by a frog. But there's a moment where it gets softer. Here it is again.

• 26:31Noam Hassenfeld?

  Wanda says she's the first person to notice it.

• 26:34Speaker 03

  These resonances had not been identified by anyone. They had not been discovered before.

• 26:41Noam Hassenfeld?

  It's still kind of mysterious. And Wanda says there needs to be more research. But she thinks that tiny decrease in volume might offer new ways to understand these dying stars and the way they give birth to matter.

• 26:57Speaker 03

  The elements that form the molecules, that form the chemical building blocks of life are produced at the final stages of a star.

• 27:08Noam Hassenfeld?

  Carbon, oxygen, nitrogen, the stuff that makes us us.

• 27:13Speaker 03

  The building blocks of life.

• 27:15Noam Hassenfeld?

  They're made by stars and blown into space when they die.

• 27:21Noam Hassenfeld?

  It was almost like Wanda was following in Bob's footsteps. Bob had heard evidence of the creation of the universe. And Wanda was hearing the first step in the creation of life.

• 27:38Noam Hassenfeld?

  These days, Wanda is an award-winning astronomer who's worked at places like the Arcebo Observatory, the Smithsonian Harvard Center for Astrophysics. And she's been traveling around the world, trying to tell everyone she knows about sonification.

• 27:52Speaker 06

  I actually had met Wanda at a couple of events and was just fascinated by her work and the idea of translating information to sound. And that just set off an inspirational light bulb for me.

• 28:05Noam Hassenfeld?

  That's Kim Arcand. She's a visualization scientist at NASA's Chandra Observatory, the biggest X-ray telescope in the world.

• 28:12Speaker 06

  X-ray data is inherently out of the human realm of vision, right? We cannot see anything besides visible light. And so having X-ray images only just seemed like it didn't really make much sense.

• 28:28Noam Hassenfeld?

  Why not listen instead?

• 28:30Speaker 06

  Why are we not prioritizing other methods of experiencing the universe around us? And so moving into sonification just made sense.

• 28:38Noam Hassenfeld?

  Kim decided to take some of her data and convert it into sound. Like, here's a sonification Kim made of what might be my favorite space photograph, the pillars of creation. You might have seen it before. It's these three towers where stars are created, made up of gas and dust. The sounds you're hearing are based on a combination of the Hubble photograph and X-ray data from Chandra.

• 29:05Speaker 06

  It's going to pan from left to right, and you're going to be hearing essentially a mapping of that data as we scan across it. The combination of the beeps and boops, if you will, of that X-ray information that's tracing all of those slightly older stars. And then you're also going to hear the sort of texture and structure of those tall pillars of gas and dust in the optical light. So this is the inner Milky Way and the supermassive black hole that's lurking at the core.

• 29:48Noam Hassenfeld?

  This is another sonification Kim made. It's the galactic center. She combined images from three different telescopes, taken in three types of light. There's an image in infrared light, which is below what we can see. There's visible light from the Hubble. And there's an image in X-ray light, which is above what we can see. And if you want to listen to this sonification with the visuals, we've got a link in the show notes where you can see it, so please check that out. But yeah, Kim decided to use different instruments to clearly differentiate between the three kinds of light.

• 30:19Speaker 06

  So in this case, the sounds that we assigned was the piano to the lowest energy from infrared light, plucky violin for the mid-range from Hubble. And then the highest energy is the Glockenspiel.

• 30:42Noam Hassenfeld?

  And the Glockenspiel was the X-ray?

• 30:46Speaker 06

  That is the X-ray light. So you could hopefully hear that little crescendo at the end. That is our supermassive black hole.

• 30:59Speaker 06

  So it's really singing in X-ray light, which is, again, very useful. This is an image that I had created with some colleagues. And I was so familiar with it, right? So familiar. But the first time I ever heard this piece all the way through, like, I really had to take a moment because it changed how I thought of this dataset. I was like, what is happening over there? What is that over there? I never noticed. This is so strong there. How did I not notice that?

• 31:31Noam Hassenfeld?

  Listening to data like this, it allows you to hear changes in everything from pitch to volume to timbre to rhythm. And you can hear them all at the same time. Listening allows you to pick out one sound to focus on over background noise, like, listening to someone you're talking to in a noisy room. And maybe, most importantly, it forces you to slow down.

• 31:55Speaker 06

  When I'm looking at a dataset that's an image, I'm looking at all of the data at one time. There's a lot of information for your eye to parse at any particular moment. But if I am listening to data of one of those same objects that I'm used to looking at, I am getting the information over time. And it just, for me at least, allows me to think through what it is I'm listening to in a very different way.

• 32:26Noam Hassenfeld?

  But I want to go one step further here. It's easy to think of astronomy as this fundamentally visual thing. You know, this pure idea of just gazing up at the stars. And if I'm being honest, that's how I felt before I started working on this story. I felt like audio was a nice complement to an image. You know, a way to double-check it, maybe a way to get a fresh take on something you've seen 100 times before, but still secondary.

• 32:56Speaker 06

  It makes sense. Like, it makes total sense. Seeing is believing is a phrase for a reason, right? But so much data from these telescopes is essentially all invisible to us. We are not able to capture it with human vision. So it has to undergo a process of transformation just to get to an image.

• 33:14Noam Hassenfeld?

  Even when we're not using infrared light or X-ray light, Images often aren't what they seem. Like that famous photo of the pillars of creation. The pillars aren't actually that red. The red's just a way to tell us there's sulfur there. The greens and blues are just a way to let us know there's hydrogen, oxygen, and nitrogen. If you were traveling in a spaceship by the pillars, it would look totally different.

• 33:38Speaker 06

  A lot of the structure that we're able to see in the pillars is existing in non-visible kinds of light, which you wouldn't be able to see any of it.

• 33:46Noam Hassenfeld?

  So what are the real pillars of creation? Is it that famous photo with the reds and greens? Is it a newer infrared photo, where there are so many stars that the pillars are almost see-through? Or is Kim's sonification just as real?

• 34:00Speaker 06

  To me, sonification is a natural extension of the data, because you're just moving it from one form of authentic data to another, right? There's no lack of validity or authenticity, because we are moving it from a visual to a sound.

• 34:22Noam Hassenfeld?

  I've been coming back to this idea over and over again, since I started working on this series. By this point, we've spent four episodes talking about how much of the world we hear is constructed by our brain. But it's not just sound. It's all our senses. I think Dan Poly, the tinnitus researcher I talked to, put it pretty well.

• 34:42Speaker 07

  Because the brain doesn't have direct contact with the physical world, everything that we perceive as consciousness is constructed from the activity of the brain.

• 34:54Noam Hassenfeld?

  Sonification is a reminder that no matter what sense we use, we're still going to have blind spots. No representation of reality is more valid or real than any other one.

• 35:08Speaker 06

  I've had multiple people who are blind or low vision approach us and say, "I didn't think I could even do astronomy, because it's so visual." Sonification of these types of objects has shown me that I might be welcomed working for NASA, working at an observatory.

• 35:28Speaker 03

  I had a group of 13 students this summer. And I remember, they said, "I never thought I would be able to do it." It was by listening to the data that I realized that I can continue forward.

• 35:46Noam Hassenfeld?

  Wanda's still pushing sonification even further. She's working with the Royal Academy of Science International Trust to launch an institute for multisensory science in Lisbon this January. And she isn't just excited about accessibility. She's excited about how scientists want to sonify 20,000 galaxies in order to look for patterns they might have missed, how they're analyzing gravitational waves from merging black holes, how they've even proposed using sonification as a new way to search for dark matter.

• 36:15Speaker 03

  It's exciting to have more people with different skills contributing to the mainstream, studying things that we never thought existed before.

• 36:33Noam Hassenfeld?

  As I was talking to Wanda, I started thinking back to the very first episode we did on this show, about Vera Rubin, the scientist who discovered dark matter, how people ignored her because she was a woman, how she was kept out of scientific institutions, how somehow she never received a Nobel Prize. There were so many moments when she could have just stopped.

• 36:58Noam Hassenfeld?

  And if that had happened, who knows? Maybe we'd still have no idea that most of the universe is missing. How many other scientific ideas are we leaving undiscovered because we're making it too hard for different kinds of people with all kinds of perspectives and sensory biases to do science? What might happen if we made it easier?

• 37:21Speaker 03

  People that are not like the current workforce in physics, astronomy, mathematics, the sciences, they will be transformed from beneficiaries to benefactors and to agents of change. If we bring more skills to science, we will have to delete the word limit. The emergence of science will be incredible.

• 38:02Noam Hassenfeld?

  This was the final episode of our series, The Sound Barrier. It was reported and produced by me, Noam Hassenfeld. I also wrote the music. Editing by Joanna Salataroff, mixing and sound design from Chris Janayala, the best kinds of explosions from Sally Helm, and really nuanced, detailed fact checking from Melissa Hirsch. Melissa checked so many facts for this series and just made all of it so much better. Melissa, you are amazing. Meredith Hadnot runs the show. Jorge Just and Julia Longoria are editorial directors, and Bird Pinkerton surveyed the scene in front of her. Hundreds of traitorous platypuses cowering while their former octopus allies stood over them, preventing them from moving. But the birds had abandoned them.

• 38:47Noam Hassenfeld?

  An aaron bird had vanished.

• 38:54Noam Hassenfeld?

  Thanks to Vartika Sharma and Paige Vickers for the beautiful artwork for The Sound Barrier series. Thanks, as always, to Brian Resnick for co-creating the show, along with me and Bird. And if any of you out there have thoughts about the show, send us an email. We're at [email protected]. You can also leave us a review or a rating wherever you listen. Really helps us out. And if you're into supporting the show and all of Vox in general, join our membership program. You can go to vox.com/members to sign up. Unexplainable is part of the Vox Media Podcast Network, and we'll be back next week.

• 39:40Speaker 08

  What's the secret to being a great host this season? Keeping things deliciously simple, like mixing Simply Cranberry into a festive drink as guests arrive, or serving up a warm mug of Simply Apple on a chilly night. That means less time behind the scenes and more time in the moment with everyone. Crafted with real fruit, Simply juices and fruit drinks make any holiday drink effortless, inviting, and completely delicious. Simply. Say yes to simple.

• 40:10Speaker 09

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