[RADIOLAB INTRO]

LULU MILLER: Do do do do do do do. We interrupt your regular Terrestrials programming to bring you breaking news in the worlds of space and poetry. That's right, breaking space poetry news, because in just a few days, NASA will be launching a spaceship from planet Earth that will travel all the way to one of Jupiter's moons, a moon called Europa. And that spaceship will be carrying fuel and radio transmitters and telescopes and thermal cameras. And a poem. That's right, a poem that will head out all the way into the stars.

LATIF NASSER: This is Radiolab. I'm Latif Nasser.

LULU: And I'm Lulu Miller.

LATIF: And today we are devoting the whole hour to this momentous launch, although with a twist.

LULU:Yes. So this hour comes to you from Terrestrials, which is Radiolab's family friendly podcast all about nature and life on Earth.

LATIF: Although it does feel like this is not terrestrial anymore.

LULU: It's a celestial edition.

LATIF: Extraterrestrial. Celestial. I like it. I like it.

LULU: Yeah, yeah, yeah. And we got really interested in what's going on with this launch. You know, why is a poem a part of it? And why this one moon in particular? Why are we going there? Because Jupiter has so many moons.

LATIF: How many moons does Jupiter have?

LULU: Well, they don't even have an answer because they keep finding new ones, but it's around 100.

LATIF: Wow!

LULU: And so we are gonna make sense of all this today. And to help, we are joined by NASA scientist Dr. Cynthia Phillips, who has spent months, years?

LULU: How long, Dr. Phillips. Working on this mission?

CYNTHIA PHILLIPS: It's been years. It's been—you know, maybe I don't want to say how many years, but it's been a lot of years.

LULU: Wait, tell us how many years! How many years?

CYNTHIA PHILLIPS: Well, so we first started planning this mission almost 25 years ago.

LULU: Whoa.

CYNTHIA PHILLIPS: When we were visiting the Jupiter system with a previous spacecraft called the Galileo and the pictures and observations that Galileo took of Europa were so cool that we were like, "We have to go back. We have to go back with a mission that just studies Europa." And so finally, 25 years later, that mission is about to launch.

LULU: Wow. And we are also joined by the one person on Earth selected to write the poem worthy of being engraved on this spaceship, 25 years in the making: US Poet Laureate Ada Limón.

LULU: Hi!

ADA LIMÓN: Hello! It's so wonderful to be with you today.

LULU: Um, that doesn't sound like a stressful assignment at all.

ADA LIMÓN: Oh, no! No stress. Very easy to try to write a poem that will be engraved on a spacecraft that hopes to speak for all of humanity.

CYNTHIA PHILLIPS: No pressure.

LULU: So Latif, I'm gonna just play the episode the Terrestrials team has put together so that people can understand more about what is happening in just a few days with this launch.

LATIF: Okay.

LULU: And I guess I'll pick up with the moment we inflict on all unsuspecting guests, it was a real highlight of my career to do this with the US poet laureate.

LULU: And now is the part where I make you sing the theme song with me.

ADA LIMÓN: [laughs]

LULU and ALAN: [singing] Terrestrials, terrestrials, we are not the worst, we are the –

ADA LIMÓN: Best-rials.

LULU: Yes you got it!

LULU: I am your host Lulu Miller, joined as always by my songbud.

ALAN: [singing] Woo hoo hoo

LULU: Alan!

ALAN: [sings] REACHING FOR EUROPA WITH A POEM!

LULU: Over the last few months we collected questions from kids all over the country and beyond, questions about what it matters to science, and why poetry is part of it. So you're gonna hear mostly from them, from you, from yourselves.

LULU: Cynthia, Ada, you guys ready?

ADA LIMÓN: I am absolutely ready.

CYNTHIA PHILLIPS: This is going to be great.

LULU: So a bunch of kids wondered of all those moons ...

AMRITA: Why Europa?

CYNTHIA PHILLIPS: Yeah, so, the Jupiter system, so it has these moons that are really, really cool looking moons, and one of them, Io, that's close to Jupiter, it has volcanoes that are erupting like all the time.

LULU: With like lava and ..?

CYNTHIA PHILLIPS: Mm hmm. There's like lava flows. There's plumes. There's like these sulfur deposits on the surface. We sometimes call it the pizza moon because seriously, it looks like a pizza. There's like red and orange and yellow and then like these little dark circle things that are actually, they’re lava flows but they kind of look like anchovies.

LULU: What!

CYNTHIA PHILLIPS: Or like olives

LULU: Wow. love that, okay.

CYNTHIA PHILLIPS: So yeah, so, Io is totally this pizza moon. But then Europa, it's the next one out and its surface is covered with ice. And then some of our models started showing us that actually under all that ice, there could be water. We think that Europa has more water than all of Earth's oceans combined.

LULU: Really?

CYNTHIA PHILLIPS: So a huge ocean. So yeah, it's a crazy place. When we think about water out in our solar system, like way out far away from the sun, this huge ocean.

LULU: Gosh, an ocean in space!

CYNTHIA PHILLIPS: Yeah!

LULU: Turns out the tagline to NASA’s mission to Europa is: “Exploring Jupiter’s Ocean World.”

CYNTHIA PHILLIPS: The reason why we've been working on this Europa mission for 25 years is that as soon as we found that ocean, we were like, there could be life in that ocean.

LULU: Wow!

LENOX: Hi I’m Lenox. I’m nine years old. I heard that the space craft is named “The Clipper”. Do you know why it’s named that?

CYNTHIA PHILLIPS: Yeah. So back in the 1800s, there were these giant sailing ships, and one of them was called the clipper ship. And it was a ship that had like these big sails on it, and it was very fast. And so they kind of like the imagery of this sailing ship.

LULU: It's like a sailboat in space. looking at maybe oceans in space. That’s neat.

CYNTHIA PHILLIPS: Yup.

LULU: Nautical-themed. It's fitting.

CYNTHIA PHILLIPS: Yes.

AARNAV: Hi. My name is Aarnav Rudraraju. I’m 10 years old. My question is: how big is the spacecraft?

CYNTHIA PHILLIPS: The whole spacecraft is going to be as big as a basketball court.

LULU: Oh!

CYNTHIA PHILLIPS: So it's going to be gigantic. This is actually one of the biggest spacecraft that we've ever built and launched.

LULU: Wow! And just to be clear there aren’t any humans on it, right? It's purely machine?

CYNTHIA PHILLIPS: Yeah.

GRAYSON: Hi my name is Grayson. I’m seven years old. My question is: what if the spacecraft blows up?

CYNTHIA PHILLIPS: Hmm. That's one of the scariest things about launch. We are all gonna be there holding our breath until it gets off the ground. So once it launches, once it's safe in space, then the chances of it blowing up are pretty small. But yeah, that's one of the scariest parts of working on a mission like this. You could spend 25 years working on something and it doesn't work. You know, something happens, something blows up. And I really, really hope that doesn't happen. But yeah, it's a real possibility.

LULU: What on Earth would you do if it did?

CYNTHIA PHILLIPS: I'd cry. Seriously. Like, I—you know, I'd cry. Because this is—you know, the spacecraft's like a friend.

EVA: Hi I’m Eva. I’m 9 years old. Have you touched the spacecraft?

CYNTHIA PHILLIPS: I have not touched it, but they don't let me touch things, right? You have to be really, really special to actually get to touch it. But I have breathed the same air as it.

LULU: So, you’ve been in the same room with it, or ..?

CYNTHIA PHILLIPS: I've been in the same room. Yeah. So we were building it in this giant clean room. And so everyone who goes in there and all the stuff, it has to be cleaned and then cleaned and then cleaned again. So we make sure we don't bring any dirt or dust or microbes or particles with us. And so I actually got to go in the clean room and, you know, they had an engineer who was making sure I didn't get too close to the spacecraft, but I got to go pretty close. And I was—seriously, I was sitting there. I was so excited.

LULU: Did you blow it a little kiss or like enclose any secret meditation or prayer on it for good luck?

CYNTHIA PHILLIPS: I didn't, but I definitely said hi to it. Like I definitely, I sent it some mental kind of like, “good luck, you're awesome,” kind of wishes to it.

LULU: All right, well switching gears to the poem engraved on the surface of that very spacecraft, a ton of kids asked a version of this question, but I am gonna toss it to Jude, aged 5, who when he heard NASA was sending a poem into space asked simply:

JUDE: What for?

CYNTHIA PHILLIPS: That's a really good question. So NASA has a tradition of putting little messages on its spacecraft. And one of the most famous was one that went on the Voyager spacecraft. So these were two spacecraft that were launched in the 1970s. They're actually still going. And, we think in, you know, like thousands of years, they might make it to a different star system.

LULU: Wow!

CYNTHIA PHILLIPS: And so when the spacecraft were being designed, scientists realized that maybe if there's an alien civilization out there, these spacecraft might be the first signs of Earth that they ever find. And so they wanted to put a message on it. And they put it in the form of what's called The Golden Record.

LULU: So, like, an actual physical record, like the kind you’d put on an old fashioned record player to play music?

CYNTHIA PHILLIPS: Yeah! But instead of just putting music, they put sounds from Earth.

LULU: Oh, wow. Okay, so but going back to Jude's original question of why send a poem into space, your answer is basically that it is supposed to be a message from Earth on the off chance an alien actually encounters it?

CYNTHIA PHILLIPS: Yeah. And whether or not anyone actually ever finds these things, it's a way of symbolically bringing humanity along for a ride. I think it's a really important process to go through thinking about, you know, what would we want to say? What traces of Earth would we want to bring with us? What is, what is the best of ourselves that we could take with us beyond this planet into space?

LULU: Whoa. What a question!

CYNTHIA PHILLIPS: Yes.

LULU: So turning now to the one person on Earth that NASA hoped could answer that question in verse form ...

ADA LIMÓN: Ugh

LULU: ... US Poet Laureate, Ada Limón.

ADA LIMÓN: We definitely need to get Taylor Swift to write this instead.

LULU: [laughs] We have got some questions for you.

ASHWIN: Hello. My name is Ashwin. I’m 10 years old. and my question is: How did you feel when NASA asked you to write the poem?

ADA LIMÓN: Yeah, wonderful. We all hopped on Zoom. And the team at NASA explained the importance of Europa, the importance of the mission. And as they talked, I thought, oh, I absolutely am so interested in doing this. And I immediately said, yes, yes, yes, yes. I want to do it. Thank you so much for asking me. Wow. What an honor.

LULU: No pause. You didn’t sleep on it? In the room?

ADA LIMÓN: No pause. No pause. And then as soon as we got off the call, I thought. Oh, no, how am I going to write this poem?

LULU: [laughs]

ADA LIMÓN: And I thought, how difficult this is going to be. And so I went from this enthusiastic, wholehearted, yes, with my whole body to being basically terrified.

MENGSU: Hi everyone! I am Mengsu. I’m a teacher. My question is, was there any mandates to write the poem?

ADA LIMÓN: Yeah. No, they gave me some parameters. You know it needs to be something that is able to be read by someone who is in fourth grade, and that it needed to include water. And it needs to be, I think it was under 200 words.

LULU: Huh.

ADA LIMÓN: And that's—that's where the real sort of fear and anxiety set in.

LULU: Because how do you actually represent something so big in so few words?

ADA LIMÓN: Yeah, exactly.

LULU: So back now to your questions about the mission at hand, the mission to Jupiter's moon, the mission to this faraway space ocean.

ROBILIANA: Hi, my name is Robiliana Santos Soriego, and I’m 16 years old. If there is marine life in the ocean, in the moon, what flavor would it be?

CYNTHIA PHILLIPS: Whoa!

ROBILIANA: Like, if we ate it, would it taste different than the fish we have in our oceans?

CYNTHIA PHILLIPS: [laughs] You know, that's not a question I thought about before.That's a really good question. Um, so, so yeah, if there's life on Europa, Very likely, it's a completely separate, independent origin of life that's totally different from Earth. And so it's possible that, you know, we don't even know if that life will be based on DNA, on the same amino acids that ours are based on. And so, if we find life on Europa, there's no guarantee that it even would be edible for humans but, you know, maybe we'll have discovered, like, a new flavor of the tastiest fish ever.

LULU: And any guesses from little things, you know about anything about its chemical composition? Like, I don't know what it might like, would it taste a little more nitrogen-y?

CYNTHIA PHILLIPS: Yeah, like, if you're making a frozen drink out of Europa, what it would taste like, you know? You're making a slushie, right? And so you take some of Europa's ice, and then you'd have to, it'd have to be a little bit salty. It could have like sulfur.

LULU: Raining down from nearby Io’s volcanoes.

CYNTHIA PHILLIPS: And be kind of stinky.

LULU: Would it maybe be fizzy? Like, if there's carbon dioxide up there?

CYNTHIA PHILLIPS: Yeah! You know, probably the chances are it's much more likely to be gross than it is to be delicious, but you never know.

ALAN: [sings] It’s an icy salty fizzy slushee. Maybe sour maybe stinky. Probably won’t want to drinky.

LULU: Well, in just a few days, the spacecraft that just might be able to get better answers to that question will blast off. And when we come back, we are gonna hear the poem that Ada finally wrote and hear questions from you about what it means. Stick with us.

LATIF: Latif.

LULU: Lulu.

LATIF: Radiolab. And today we're running a special hour from Terrestrials, which is our science podcast for kids. And this episode is all about a NASA launch coming up in just a few days. It is scheduled for October 10, although that could change depending on the weather. Either way, this mission was 25 years in the planning.

LULU: By the way, if you would like to watch the spacecraft launch into the air live, you can do that. Just check out NASA's Jet Propulsion Lab YouTube, or the website NASA-plus, which is just plus.NASA.gov. It's scheduled for October 10 at 12:31pm Eastern Standard Time at plus.NASA.gov.

LATIF: Lulu what's next?

LULU: Okay, so reminder: the spacecraft, the Clipper, it's about the size of a basketball court, and it will soon be headed toward one of Jupiter's moons, a moon called Europa that very likely has an ocean. Liquid water. They think there's more water there than on Earth.

LATIF: Hmm!

LULU: And When we left off, US Poet Laureate Ada Limón had been asked to write a poem that would be engraved on the outside of the spaceship to represent a message from all of humanity! No bigs! But she was stuck. Like real stuck!

ADA LIMÓN: Terrified.

LULU: So we resume with the tale of what she did to move through that, which we learned about thanks to questions from kids all over the world.

ELIZABETH: My name is Elizabeth and I’m 10 years old. What steps did you take to write the poem?

ADA LIMÓN: Well, I had about three months to write the poem. And I was going to Hawaiʻi, to a town, I'm not kidding, named Haʻikū,

LULU: [laughs]

ADA LIMÓN: And I was staying in the house of a former US Poet Laureate W.S. Merwin, And so my husband and I went there. It's inside an incredible palm forest. All of these beautiful, different varieties of palm trees. And so I got to watch all of the different species of birds and all the geckos inside and outside the house. And I had this real space to think and sit with the idea of what I wanted to offer. And so I began writing the poem.

ADA LIMÓN: I was trying to imagine the audience being sort of out in space, right? Whether there were other beings out there, whether the audience was the stars themselves. And I kept imagining a loneliness. And so I would read a draft to my husband, and he would say, “Hmm, you know, I think you need to stop writing a NASA poem.”

LULU: What do you think your husband heard when he said that?

ADA LIMÓN: I think he was hearing maybe more of a scientific approach, more stiff and formal type of writing. Maybe more of following the assignment. Thinking of it as presenting facts about Europa. And so what I needed to shift was, oh no, I need to speak to Europa and have this be a reaching out.

LULU: Was there anything that like–a bird or a tree or a moment–that led you down the right path, the rabbit hole that would turn into the more us poem? I dunno. There might not be. But do you have anything in your head?

ADA LIMÓN: Yeah! I was in Hawaiʻi, and I was staring at this palm frond and the palms really move. They sort of glow and move. They have a bounciness to them in the wind. And there was a little gecko that was stuck on the underside, that was completely upside down. And he was hanging on this palm frond. And I thought, “How amazing! That little dude is just, you know, bouncing in the wind back and forth.” And I thought of the line: we too are made of wonders.

LULU: “We too.” Meaning, like, both Europa and Earth are both made of wonders?

ADA LIMÓN: Yeah. That's where the poem shifted. Then I realized that really the audience was us here on this beautiful planet. And it includes everyone on earth. And it also includes plants and animals. So it needed to be from all of us to all of us and the, “I”, “me”, “Ada” had to be taken out of it. And that's where the poem really reached a momentum, where I could follow it through.

MAADHAV: Hi. My name is Maadhav Sharma. I’m 11 years old. What did you struggle with to come up with in this poem?

ADA LIMÓN: Oh, that's a great question. I think that what I struggled with the most was how to use a we. To be honest, I am someone that's always been a little suspicious of a 'we.' You know, as a Latina, as, um, a woman, there are times where I even think of “we the people” and I think, am I included in that “we”? I want to know if I'm included in that “we”.

LULU: And that, of course, is from our Constitution.

ADA LIMÓN: Exactly. And so I think that as a poet, I often don't use we, And so, um, I think the most difficult thing I had to do was actually surrender to the “we”. And remember that, uh, that the “we” had to represent everybody and to try to include trees and animals and plants. And so I had to really release that idea of the “I” and make room for my most communal voice. And that was where the poem took hold.

LULU: Really took hold. That poem is now engraved into the spacecraft, and tomorrow, her words will literally touch the cold of space, collecting stardust as they blast towards Jupiter’s moon. She did it. She found a way to write a message from ALL of us here in this water world to Jupiter’s water world in under 200 words.

LULU: All right, well, would you be up for reading it?

ADA LIMÓN: I would be honored.

ADA LIMÓN: In Praise of Mystery: A Poem for Europa

Arching under the night sky inky

with black expansiveness, we point

to the planets we know, we

pin quick wishes on stars. From earth,

we read the sky as if it is an unerring book

of the universe, expert and evident.

Still, there are mysteries below our sky:

the whale song, the songbird singing

its call in the bough of a wind-shaken tree.

We are creatures of constant awe,

curious at beauty, at leaf and blossom,

at grief and pleasure, sun and shadow.

And it is not darkness that unites us,

not the cold distance of space, but

the offering of water, each drop of rain,

each rivulet, each pulse, each vein.

O second moon, we, too, are made

of water, of vast and beckoning seas.

We, too, are made of wonders, of great

and ordinary loves, of small invisible worlds,

of a need to call out through the dark.

CYNTHIA PHILLIPS: My first reaction was just “Wow.”

LULU: NASA scientist, Cynthia Phillips again.

CYNTHIA PHILLIPS: And I think my second reaction was also, “Wow.”

ADA LIMÓN: We got to visit the jet propulsion lab. We got to see the Europa Clipper being built in the clean room. And I went into a sound booth and recorded the poem, and I think I did it maybe three or four times. And when I came out, I hadn't realized that the sound was being pumped into the next room over.

CYNTHIA PHILLIPS: Oh my goodness, if I thought reading it myself was amazing, listening to her read it, oh. It makes me tear up, honestly.

ADA LIMÓN: When I came out, everyone was crying and clapping.

LULU: Oh!

LULU: All right. Now back to our kid questions.

AMY: My name is Amy. My age is 13. The line that I liked was “We too are made of wonders, of great and ordinary loves." What does “ordinary loves” mean?

ADA LIMÓN: Oh, I love that you asked that question. You know, I was thinking about how poets and artists and all of us, we like drama. We like big loves. We like really epic stories. And I wanted to praise the little loves. Maybe it's the love between two friends, and they're just friends and they can say, I love you. Maybe it's like, just like you and your mom and you can say, "Oh, I love my mom." The moment where you can say, "I love that coffee cart guy, who gives me the good donut. I love that bird in the tree, I love that every day when I get on the bus that particular bus driver always says howdy instead of good morning."

LULU: And that line again, in the poem, you're talking about the similarities with Europa and the water up there, and also the ordinary loves up there. What kind of ordinary loves do you imagine might be on Europa?

ADA LIMÓN: Yeah. I mean, I'm so curious because it could just be, you know, the way certain elements love each other so that they bond, you know?

LULU: [laughs] Yeah!

ADA LIMÓN: It’s just the different kinds of attachments that happen every day.

SAMANAA: Hi, I'm Samanaa. I'm 13 years old. My question is, the things we've sent up so far mostly focuses on the good parts of being human, but what about the bad parts, like war and climate change?

ADA LIMÓN: Yeah, I think that's a great question. I don’t want to not recognize how hard we can be on one another and the destruction we’re so deeply capable of. And that’s there in the poem. That's one of the reasons that I wanted to put in, “grief and pleasure.” You know, that there's sun and shadow, but then it's followed by the line, “it is not darkness that unites us”. The selfishness, the lean towards war, the things that keep us separate. I don't think that those things define us.

CAITLIN: My name is Caitlin and I'm 14 years old. I want to know why people would think that people in Europa would speak English if there's people on our planet that don't even understand English.

CYNTHIA PHILLIPS: That’s a great question. We've transited messages into space using radio waves. And those messages have been encoded using math. Because we think that math is probably a much more universal language than say like English or Spanish or something.

LULU: Hmm!

CYNTHIA PHILLIPS: But yeah. So the message that we're sending with Europa Clipper, it was written in English, but we thought about the whole other language thing. And so we took the word for water in just over this huge variety of languages as spoken by a native speaker, and then we encoded those into these waveforms.

[ARCHIVE CLIP: Aqua, ur, miri.]

CYNTHIA PHILLIPS: The languages were chosen by a team of professional linguists to represent languages from, you know, every different language family.

[ARCHIVE CLIP: miso, amasi, nero, vater, vesi ...]

CYNTHIA PHILLIPS: And in the center of the design, is an encoding for the American Sign Language word for water.

LULU: That sign by the way is made by holding up your three middle fingers like a W, and then bouncing them on your chin a couple times.

CYNTHIA PHILLIPS: Yeah.

LULU: I love that.

ASHANTI: Hi, my name is Ashanti. 13 years old. How can feel the astronauts, when they go to space, how they feel a long time with they no have family or friends with them?

CYNTHIA PHILLIPS: Hmm. Yeah, that's a really good question. So yes, I think that being in space is an intensely lonely experience. What I've heard from astronauts who are up on the International Space Station, um, the favorite thing that they like to do whenever they have time when they're not working or sleeping is they like to look out the window down at the Earth.

LULU: Hmm. And you think that looking out the window is a kind of longing?

CYNTHIA PHILLIPS: Yeah. Yeah.

LULU: It’s a kind of evidence of loneliness?

CYNTHIA PHILLIPS: To say, "Yep, the Earth is still there, you know. I will get to go home."

ETHAN: Hi, my name is Ethan. And I’m 12 years old. Do you think there are any similarities between writing poetry and space exploration?

CYNTHIA PHILLIPS: I think there really are. When you write a poem, you're trying to, in a few words, capture something that's bigger than the poem itself. And you think of a spacecraft. It's something that's crafted. It's something that's engineered, that's created. It's kind of the same hands-on sort of almost artisan nature in both cases, right? So you're crafting it, but then you send it out into the world. You send it out into space, and you see what comes back. Just like a poem or a song can take on meaning and resonance beyond kind of what was originally intended.

ADA LIMÓN: And that's what's sort of fun about poetry, is that it begins in curiosity and then it ends in more curiosity. And exploration is the same way. We begin with a question. We get a little bit of an answer, and that means, oh! That leads us to another question.

LULU: I love that, it’s like all of that intense crafting of a spacecraft or a poem that comes from the human mind, gets you far beyond the human mind.

ADA LIMÓN: Yeah. All of the arts and science in that way exist in questions, in wonder, in interrogation. They really make a beautiful pairing.

ADA LIMÓN: Thank you so much. It has been such a pleasure to talk with you all.

CYNTHIA PHILLIPS: Thank you for such great questions. This was really fun.

LULU: Thank you so much Ada, Cynthia, for your work, for your time chatting with us. I will definitely be watching the launch and crossing my fingers for The Clipper big time. Latif, do you think you'll watch?

LATIF: Yeah, of course. I look for any excuse to procrastinate.

LULU: Do you want to remind people how they can watch too?

LATIF: Yeah. Okay, so the launch is scheduled for October 10. That could obviously change due to weather, but if you want to stay up to date, go to NASA-Plus. That's plus.NASA.gov. Plus.nasa.gov for updates on timing. And then when it's time, just watch it live. See the emotions and the smoke cloud. And can you see the poem? Probably not. But, like, you can imagine, you can projectively imagine it.

LULU: We'll see. And then hang tight because we've got just a little more Radiolab coming up after this break.

LULU: Lulu.

LATIF: Latif.

LULU: Radiolab.

LATIF: We just heard a special presentation from our spin-off show Terrestrials about an upcoming NASA launch to Jupiter's moon Europa. Besides the launch of that craft, we wanted to remind everyone we have also launched the new season of Terrestrials. So go check it out.

LULU: Slightly less momentous, but I'm excited. Yeah, you can go find that. Just search for the Radiolab for Kids feed and you'll see tons of new episodes there. It is kid friendly, but adults are very welcome too.

LATIF: And before we end today, we had a little extra time, so we wanted to look back at the first really big message that went out into space. The Voyager, as we briefly mentioned, went out with a golden record full of sounds of Earth back in the 1970s. There are actually two Voyager spacecraft, Voyager 1 and Voyager 2. And we sent them out and they're still going. They have both crossed beyond the heliosphere's outer boundary. They're now in interstellar space.

LATIF: It was actually so dramatic just this last few months, like they, they stopped working and then they started working again. So much drama. But anyway, back in the 1970s when we launched the Voyagers, and the question back then was, like, what should we put on this record? You know, it was the first time anyone had done anything like that. And so our original host of this show, Radiolab, Jad Abumrad, he sat down with one of the people tasked with figuring out what should go on that record. Her name was Ann Druyan. This is one of my favorite all time Radiolab stories.

LULU: Me too. It's beautiful.

LATIF: And we thought it would be nice to hear it again before we all watched this launch. The message that inspired the message. So here we go, turning it over to Jad.

JAD: It began for us when we spoke with this writer ...

ED DOLNICK: Yes, I hear you booming.

JAD: Ed Dolnick is his name. And he told us a story about ...

ED DOLNICK: So this is Isaac Newton's story, for the most part.

JAD: And it's a story that involves the Earth, the heavens, God, humanity, and you might as well throw in the apple.

ED DOLNICK: The one thing everybody knows about Newton is that an apple fell from a tree and bonked him on the head.

JAD: Which isn't true, I was told. Right? Isn't that apocryphal?

ED DOLNICK: It's probably not true, but it's a story that Newton himself told.

JAD: Oh, really?

ROBERT: Oh!

JAD: Because Newton, according to Ed ...

ED DOLNICK: All his life had this notion that he was different from other people. Not only different from, but better. He had a pipeline to God. God was whispering secrets, the secrets of creation into his ear. No one else had been blessed in this way. Other people's role in life was simply to bog him down.

ROBERT: [laughs]

ROBERT: Not what I would call a modest guy.

JAD: No. But ...

ED DOLNICK: At any rate ...

JAD: Our story begins around 1665. Newton is at Cambridge. He's a student.

ED DOLNICK: And Cambridge is hit by the plague. They send everybody home, because although nobody understands how the disease works, they know that if people are crowded together they tend to all get it. So everybody go your separate ways.

ROBERT: So this is kind of an enforced summer vacation.

ED DOLNICK: [laughs] Right.

JAD: And he's like 19 or 20 at this point?

ED DOLNICK: He's 21, 22.

JAD: Okay.

ED DOLNICK: Newton goes home to his mother's farm.

JAD: Mom is like, "Cool, now you can help me on the farm." But ...

ED DOLNICK: He says no.

JAD: Because he has a plan. He brought some books home.

ED DOLNICK: A bunch of textbooks.

JAD: And he locks himself in his room.

ED DOLNICK: And sets himself not only to having mastered all the science that had ever been done, but to plunging on ahead of everyone else on his own, motivated by this religious faith that everything in the universe was set up by a god who wanted someone to crack the code. Newton believes he's the one.

JAD: I mean, what was he doing in his room? Was he sitting there with a thousand giant textbooks?

ED DOLNICK: All that's known is that he did this.

JAD: He just went into his room and came out with what we're about to talk about.

ED DOLNICK: He came out with how gravity works, how light works, how rainbows work, how the tides work. And then, having done all that ...

JAD: In a [bleep] summer he did all this?

ROBERT: [laughs]

ED DOLNICK: Yeah!

ROBERT: What did you do on your summer vacation, Jad? I know my summer, I learned how to fold sheets like Marines do, which I thought was pretty good too.

ED DOLNICK: Right.

ROBERT: So after having one flash of insight after another, Newton now sets his mind to one of the great problems of all time, which for our purposes we will call the problem of the moon.

JAD: And just to set this up ...

ED DOLNICK: What everybody before Newton and Galileo thought is there were a bunch of ordinary things here on Earth, like rocks, and they behave in the ordinary way that we know.

JAD: You know, pick up a rock, let go, it falls.

ED DOLNICK: And there are a bunch of much more different, mysterious, elegant, perfect things in the sky.

ROBERT: Like the moon. Which doesn't fall, it just floats there.

JAD: So one could conclude that the moon has its own separate set of laws.

ED DOLNICK: There are one set of laws that work here on Earth, and another set that work in the heavens. And there's no reason it should be the same set of laws any more than New York's laws should be the same as Paris's laws.

JAD: Kind of makes sense, actually. Heavenly things float. Earthly things fall.

ROBERT: But then here's where the problem begins: Newton and a bunch of people at that time had gotten a hold of this newfangled thing called a telescope.

JAD: And one of the things they saw ...

ED DOLNICK: ... was that the moon wasn't this mysterious, heavenly body that they see. It was a big rock. A regular, lumpy, potato-ish rock.

JAD: Uh-oh. People were like "Huh."

ROBERT: But Newton being, of course, Newton thought, "Now wait a second."

ED DOLNICK: If the job of a rock is to fall, and if the moon is just another rock ...

ROBERT: Why doesn't it fall down?

ED DOLNICK: Exactly so. What's it doing sitting up there night after night?

JAD: Good question. And it's at this point that Newton, sitting in his room or wherever he was we can imagine, makes a crazy mental leap. He thought back to a little thought experiment that Galileo had come up with, which initially might not make much sense, the connection ...

ROBERT: But it pays off.

ED DOLNICK: And here's the set up: you've got someone standing in a big field with a gun that he's about to shoot. And next to that person with this gun is a person holding in his hand a bullet.

JAD: So you've got a person holding a gun and a person holding just the bullet side by side.

ED DOLNICK: And the bullet in the hand and the bullet in the gun are exactly the same height above the ground. Now somebody says, "Ready, aim, fire." And at the instant he says "Fire," the man with the gun shoots that bullet horizontally, and at that same instant the man next to him holding the bullet in his hand opens his hand and the bullet drops.

ROBERT: So there's one bullet zipping along and then falling, and then the other one just falls.

ED DOLNICK: Right. We shoot the bullet out of the horizontal gun, and we drop the bullet from right next to the gun.

JAD: At the same time.

ED DOLNICK: Yes. Both bullets will hit the ground eventually, but when they do they'll be far apart. And Galileo's riddle was: which of those bullets hits the ground first?

JAD: Well, I mean, that's ...

ROBERT: Everybody would know that the one that would hit the ground first is the one that you just dropped because the other one has to go all that distance.

ED DOLNICK: So this is a hard riddle. And the answer is ...

JAD: Well, wait. Why is it such a hard riddle? Because I would think that the bullet you drop is just gonna hit first. The gun's gotta go all the way.

ED DOLNICK: No. Those two bullets both hit the ground at the exact same instant.

ROBERT: Really?

ED DOLNICK: That's an experimental fact.

ROBERT: The bullet from the gun and the bullet from the hand lands at the same time?

ED DOLNICK: Yes. This bullet that shot horizontally, it doesn't go like Wile E. Coyote running off a cliff. It doesn't go straight, straight, straight, straight and then fall. It's curving as it goes.

JAD: And the thing that causes it to curve as it goes, of course, is gravity. It's the same gravity that is pulling the bullet that you drop. Same gravity. Same pull. Same speed. So counterintuitively, when you drop a bullet and it falls for this long, when you fire the gun it'll also fall for that long, even though it ends up a mile away. See? That was Galileo's riddle.

ED DOLNICK: And that's as far as Galileo took it.

JAD: Yeah.

ED DOLNICK: Newton looked at that and he said something smart.

JAD: First thing he said is, "Okay, this field? Let's not pretend that this is some ..."

ED DOLNICK: "Perfectly flat field that goes on forever."

JAD: "No. We're on the Earth, and the Earth is round."

ED DOLNICK: And what roundness means is that the ground curves away below horizontal.

ROBERT: So really what's happening is that as the bullet is shooting across the field and falling to the Earth, the Earth at the same time is very gradually curving away from it.

JAD: Now of course, most guns, you know, they don't shoot the bullet very far, and at that short distance the field is still pretty much flat.

ROBERT: But here's what Newton thought: "What if you could find ..."

ED DOLNICK: "Just the right gun."

ROBERT: "That could shoot that bullet not just across a field but across thousands of miles. And ..."

JAD: "What if ..."

ED DOLNICK: "As it falls ..."

JAD: "That bullet curves down towards the Earth ..."

ED DOLNICK: "In just the same as the Earth is curving ..."

JAD: "Away from it?"

ROBERT: In this scenario ...

ED DOLNICK: The bullet that we've shot will keep falling and falling and falling, but the Earth keeps falling and falling and falling away from the bullet. So the bullet falls forever, the Earth curves forever, the picture never changes.

JAD: So the bullet then does what?

ED DOLNICK: The bullet is in orbit. Hundreds of years before Sputnik and other satellites, Newton has invented the satellite. And on top of that, he said, when we see rocks like the moon that are not falling, the reason we think they're not falling is because we misunderstand. Really, just as the gun launched a bullet on Earth and it goes and never falls, God who is presumably a terrifically strong pitcher, launched the moon around the Earth at just such a rate that that would continue in its circle around us forever. This is a perpetual dance. The partners are bound together, but they never come close and they never break up, either. It's this endless round.

ROBERT: From which there is no escape.

ED DOLNICK: What this does, what Newton did is take the moon out of the domain of poets and musicians, the golden orb and this kind of thing, and lasso it to the same rules that we use here on Earth.

JAD: In other words, what he showed was that in a very real way, there's no separation between us and the heavens.

ED DOLNICK: The same set of laws does govern everything. "It's one universe and I've explained it all."

ANN DRUYAN: And once you figure out the laws of gravitation, then you can send spacecraft to ...

JAD: Mars ...

ANN DRUYAN: Jupiter ...

JAD: Saturn. Anywhere.

ANN DRUYAN: Out there.

JAD: If you're a Radiolab listener from way back, you might recognize that voice. That's Ann Druyan.

ANN DRUYAN: Hi.

JAD: One of the first stories we did, actually. I interviewed her about working on the famous golden record. You remember this.

ROBERT: Sure.

JAD: So the idea at the time was to put this record on the Voyager capsule, send it into space, and on the record would be all these sounds that represented, you know, us.

ANN DRUYAN: A kiss. A mother's first words to her newborn baby. Mozart.

JAD: In any case, Ann was the one who was in charge of choosing all the sounds to put onto that record. She and Carl Sagan worked together on that project. And here's the thing: we stopped our story as the rockets took off, but obviously that was just the beginning of the story. And the Voyager capsules right now, are about to make a kind of escape that Newton could have only dreamed of.

LYNN LEVY: Okay.

JAD: The record thing.

JAD: And our producer Lynn Levy has been ...

LYNN: Sorry, I just turned my headphones up way too loud.

JAD: ... has been following this story.

LYNN: Ow!

JAD: Yeah, just turn it down.

LYNN: Yeah.

JAD: Okay, so pick it up where we left off.

LYNN: Okay, so, like, the point of the mission wasn't really to deliver this record. It was to go out and look at all the planets in the outer solar system.

JAD: Mm-hmm.

LYNN: So starting in 1977, these two little spaceships ...

ANN DRUYAN: Two spacecrafts, Voyager 1 and 2 ...

LYNN: ... went racing away from Earth snapping pictures.

ANN DRUYAN: And so every time Voyager would reach another planet, you know, all of the Voyager people would get together, go into the imaging room, and see the pictures come from the outer solar system.

LYNN: Do you remember seeing them?

MERAV OPHER: I remember as a child seeing them in Life Magazine. You know, I was seven when Voyager was launched. So ...

LYNN: This is Merav.

MERAV OPHER: I'm Merav Opher, professor at Boston University.

LYNN: As a grownup, she became part of the Voyager team.

MERAV OPHER: All the pictures that as a kid you look at the books and to see how Neptune looks, how Jupiter looks.

ANN DRUYAN: You know, just a complete revelation.

MERAV OPHER: Saturn.

ANN DRUYAN: The image of Saturn.

MERAV OPHER: Technicolor.

ANN DRUYAN: Like pink and ...

MERAV OPHER: reddish.

ANN DRUYAN: ... turquoise colors ...

MERAV OPHER: Yellow and ...

LYNN: And those rings. Just spectacular. They could see active volcanoes on one of the moons of Jupiter.

ANN DRUYAN: Finally, that vision of Neptune, of this blue jewel.

LYNN: Really blue.

MERAV OPHER: It all came from Voyager. We had no idea how they looked like before Voyager.

LYNN: Neptune was the last big, cool planet, and it was the last thing that they were supposed to photograph. After that ...

MERAV OPHER: The cameras were going to be shut off to save energy.

LYNN: But ...

MERAV OPHER: Carl Sagan convinced them to turn Voyager back to Earth and take a final picture.

LYNN: So on Valentines Day, 1990, one of the ships slowly rotated so it was facing back to Earth, and it snapped a picture.

ANN DRUYAN: One last picture.

JAD: Describe it.

LYNN: So it's mostly empty. It's pretty dark. You can see sort of streaks of light coming from the sun. And then you honestly wouldn't notice it if it wasn't pointed out to you, but down in one corner ...

ANN DRUYAN: Kind of suspended in a sunbeam ...

MERAV OPHER: There is a very small dot of blue.

ANN DRUYAN: A pale blue dot. That was us.

LYNN: In Carl Sagan's words ...

ANN DRUYAN: "Everyone you ever knew, everyone you ever loved, every superstar, every corrupt politician, just everyone in all of history, everything, the sum total. Think of the rivers of blood that have run so that one indistinguishable group could have momentary domination over a fraction of that pixel."

LYNN: It was one of those really rare images.

ANN DRUYAN: Every single day I would hear from people who take that pale blue dot so deeply to heart.

LYNN: It was a complete reframing.

MERAV OPHER: After that, the cameras were turned off.

LYNN: But here's the thing: the ships kept going, drifting through the darkness. Even though they weren't taking pictures anymore, they were using, like, their other senses: little instruments that detect how many particles are around, what the temperature is. So they were hurtling through this empty space really fast, measuring, sending that data back, and scientists like Merav were there listening and waiting.

JAD: For what?

MERAV OPHER: It was not clear.

LYNN: But they knew at some point these capsules would get to the edge.

JAD: The edge of what?

LYNN: The solar system.

JAD: The solar system has an edge? I thought it was just a big spiral.

LYNN: It has an edge. It's like a bubble.

MERAV OPHER: See, the sun has a wind. Every star has a wind, but the sun has its own wind.

LYNN: That blows out through the solar system.

ANN DRUYAN: It's very fast.

MERAV OPHER: It can be between 400 to 800 kilometers per second.

LYNN: Anyway, it blows out from the sun, past all the planets, and it keeps everything else out.

JAD: Oh, so it's like blowing up a balloon?

LYNN: Yeah.

JAD: The wind gives it a shape.

LYNN: Right. So these little things are cruising out towards this edge, wherever it is. Scientists don't quite know where it is or what it is. The guys in the control room are pinging the ships and, like, "Hey, what's up? What do you see?" And the ships are like, "Nothing." "Well, how about now?" "Not much." "Now?" "Nothing."

JAD: And how long before they actually see something?

LYNN: 14 years.

JAD: Oh, man. That's like driving through Kansas but, like, a million times worse.

LYNN: But, there comes a day ...

MERAV OPHER: End of 2004.

LYNN: Where they stop listening for a while because NASA only has so many antennas, and they have to use them to listen to everything.

JAD: Mm-hmm.

LYNN: So for a little while, the Voyager team's like, "Okay, you guys over there can use the antennas. We're going to lunch."

JAD: Yeah. I mean it's not like anything is happening.

LYNN: Nothing's happening anyways. It's been 14 goddamn years.

JAD: Knock yourself out.

LYNN: You guys? It's cool. And they come back a few hours later, start listening again, and ...

MERAV OPHER: It happened very sudden.

LYNN: ... everything has totally changed.

JAD: Really?

LYNN: All of a sudden? Boom!

MERAV OPHER: The speed of the wind dropped from around 380 kilometers per second to 100.

LYNN: Instantly. Just like all at once.

MERAV OPHER: Instantly.

LYNN: And then everything out there started to get messy.

MERAV OPHER: Very turbulent. Much more turbulent than before. Particles are also behaving a very different way, and the fields are very weird.

JAD: The fields?

MERAV OPHER: The magnetic field?

LYNN: So just like the sun has a wind ...

MERAV OPHER: The sun has a magnetic field as well.

LYNN: The field starts at the sun and then curves out in this kind of graceful arc through the solar system.

MERAV OPHER: And how the sun rotates creates what people call a ballerina skirt.

LYNN: You know how, like, a skirt will flare if you spin around real fast?

JAD: Mm-hmm.

LYNN: That's apparently kind of what this field looks like.

JAD: Huh.

LYNN: But way out there, it seemed like the skirt had started to fray, maybe tear a little. Threads had broken off and seemed to be floating around on their own, not connected to anything.

JAD: So what does this all mean? I mean, if the fields are breaking down and the wind is dying down, you said the wind is what actually creates the space of the solar system, does this mean we're out?

LYNN: No. I kind of thought that was what was happening, but no. It's not out and it's not quite in. It's in the edge of the bubble.

JAD: It's in the edge?

LYNN: Yeah. But it's not like a little, thin edge, it's a thick edge.

JAD: Huh. So the edge isn't just a line that you cross, it's a place.

LYNN: Yeah.

ANN DRUYAN: And while we listened, the two Voyager ships moved through this edge for several years.

MERAV OPHER: Then something very interesting happened. The wind on Voyager 1 stopped.

JAD: Like completely stopped?

MERAV OPHER: Yeah.

JAD: So now we're out?

LYNN: No.

ANN DRUYAN: No.

LYNN: I mean ...

MERAV OPHER: This is what people thought. But the other measurements ...

LYNN: Like temperature, number of particles, the magnetic field ...

MERAV OPHER: Doesn't tell us we're out of the bubble. Nature surprised us again.

ANN DRUYAN: So now we think there's a place at the edge of our solar system.

MERAV OPHER: Right at the edge.

LYNN: The edge of the edge ...

ANN DRUYAN: That's utterly still. No wind at all. A pause.

MERAV OPHER: People are calling it a stagnation layer, and there is a big discussion as to why this layer exists and how thick it is.

ANN DRUYAN: And by how thick it is, she means when will it end? Because once we get past this ...

LYNN: So has anything ever crossed this boundary before?

MERAV OPHER: No. This will be the first man-made object to leave any star. And Voyager was right there, smiling, touching that boundary.

ANN DRUYAN: You know, you only do those things first once, like your first kiss and your first taste of alcohol. Your first time driving a car. The first time you see the ocean. These things open up a whole new world. The first time out of the solar system.

JAD: So when is it gonna freakin' happen?

LYNN: It might've happened while we were talking.

JAD: Gah!

MERAV OPHER: We're thinking from now, any moment now, next couple months, or three years from now, four years from now. It's close.

LYNN: Every day I open my Google alert for Voyager and I look and see did it happen today?

JAD: Do you really?

LYNN: Because if it happens before this show goes out I'm gonna be pissed.

JAD: Every day?

LYNN: Yeah.

JAD: It's the first thing you do in the morning?

LYNN: No.

JAD: All right.

LYNN: Like, the third thing.

LULU MILLER: This is Lulu now. So it's been years since that piece first aired, and Merav, did it cross over?

MERAV OPHER: It did! It did! It was 25th of August, 2012, the Voyager went across.

LULU: Wow! So it was just a few months after.

MERAV OPHER: So it was just after.

LULU: After that.

MERAV OPHER: Right. It was really, really close.

LULU: And what did it find?

MERAV OPHER: It's still.

LULU: It's still?

MERAV OPHER: Yeah. All the particles that come from the sun disappeared.

LULU: Hmm.

MERAV OPHER: It's really like an edge and you're entering to the realm of interstellar medium that is, you know, the stuff that comes from other stars. If you could put it in sound, you will see a lot of turbulence and then when you cross the edge it's much quieter.

LULU: Oh, so it did find an even deeper quiet.

MERAV OPHER: Right. Right. Yeah.

LULU: I do really like to just think about and imagine that little spacecraft out there, floating in the stillness and that silence.

LATIF: That'll do it for today. I'm Latif Nasser.

LULU: I'm Lulu Miller.

LATIF: This episode was produced by Mira Burtwintonik, Ana Gonzalez, Arianne Wack, Alan Goffinsky, Joe Plord and Lulu Miller.

LULU: Reminder, if you want to watch the launch and stay up to date on all things Clipper launch related, just go on over to plus.NASA.gov .

LATIF: And also remember to check out Terrestrials. Tons of new episodes coming out right now. Full of joy, nature stories, a way to cleanse your mind and timeline and everything. It's a little haven, so treat yourself to that.

LULU: Huge special thanks to the teachers and schools we worked with, including Simone Larson, Sarah gates, Caleb Wagner, Street Lab, CMSP327 in the Bronx. Go Sharks. And to WNYC's awesome community partnerships editor, George Bodarki. And to Gretchen McCartney, Michael Takins, Vaughn, Ashley Fielder. And biggest thanks to all the Badgers, kids with badgering questions from all over the country. Literally hundreds of you with great questions. We couldn't get to all of them, but we appreciate all of you. Support for Terrestrials is provided by the Simons Foundation, the Arthur Vining Davis Foundations, the Kalliopeia Foundation, and the Templeton Foundation. Thank you. Catch you in a couple spins of this watery old planet of ours.

LATIF: Blowing a kiss to the Clipper.

 

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