[RADIOLAB INTRO]

ROBERT KRULWICH: So you're gonna identify the Washington place? Because I can't remember.

JAD ABUMRAD: Yeah, yeah, yeah.

ROBERT: Okay. Three, two, one. 

JAD: Ready?

ROBERT: I am ready. But we should tell the audience that we're not gonna—we're gonna start this not in our usual studio spot.

JAD: Not here-here, where we're sitting now. Here.

[audience clapping and cheering]

JAD: Just to explain, this is the Shakespeare Theatre in DC. Recently, Robert and I were there in front of about 800 folks just trying out some material for the show.

ROBERT: Beginning with this story which comes from Plato—actually, by way of Aristophanes. It's a 2,400-year-old story.

JAD: Breaking news, in other words.

ROBERT: Yeah, and it goes like this. 

ROBERT: Once upon a time, he says, people were not born separate from each other, they were born entwined, kind of coupled with each other. So there were boys attached to boys, and there were girls attached to girls, and of course boys and girls together in a wonderfully intimate ball. And back then, we had eight limbs. There were four on top, four on the bottom, and you didn't have to walk if you didn't want to. You could roll. And roll we did. We rolled backwards and we rolled forwards, achieving fantastic speeds that gave us a kind of courage. And then the courage swelled to pride, and the pride became arrogance. And then we decided that we were greater than the gods, and we tried to roll up to heaven and take over heaven. And the gods, alarmed, struck back. And Zeus, in his fury, hurled down lightning bolts and struck everyone in two, into perfect halves. So all of a sudden, couples who'd been warm and tight and wedged together, were now detached and alone and lost and desperate and losing the will to live. And the gods, seeing what they've done, worried that humans might not survive or even multiply again.

ROBERT: And of course, they needed humans to give sacrifices and to pay attention to them. So the gods decided on a few repairs. Instead of heads facing backwards or out, they would rotate our heads back to forward. They pulled our skin taught and knotted it right here at the belly button. Genitalia too were moved to the front so if we wanted to, you know, we could. And most important, they left us with a memory. It was a longing for that original other half of ourselves, the boy or the girl who used to make us whole. And that longing is still so deep in all of us—men for men, women for women, men for women, for each other—that it has been the lot of humans ever since to travel the world looking for our other half. And when, says Aristophanes, when one of us meets another we recognize each other right away, we just know this, we're lost in an amazement of love and friendship and intimacy. We won't get out of each other's sight even for a moment, these are people, he says, who pass their whole lives together and yet if you ask them, they could not explain what they desire of each other, they just do.

JAD: Very nice.

ROBERT: Thank you, thank you very much. Thank you. Oh!

[applause]

JAD: So here's the thing: that story got us started on a little journey, which really began just thinking about wholeness and oneness and halves looking for each other.

ROBERT:  In all varieties of ways.

JAD: Mirrors and shapes.

ROBERT: Relationships, beauty.

JAD: The birth of the universe, the nature of life.

ROBERT: All of these things either have a simple deep beauty ...

JAD: Or not. I'm Jad Abumrad.

ROBERT: I'm Robert Krulwich.

JAD: …this is Radiolab, and today, for this hour, we are desperately seeking ...

ROBERT: Symmetry.

JAD: ... symmetry. By the way, that was Zoë Keating on cello, we'll hear more from her throughout the hour because she's awesome. All right, Bobby K.

ROBERT: Mm-hmm?

JAD: I'm still thinking about Aristophanes.

ROBERT: Okay.

JAD: And do you ever wonder what actually happens when two people click, when the halves kind of meet?

ROBERT: Meaning what?

JAD: You know, you're going through your day, maybe you're at a party.

ROBERT: Yeah.

JAD: You meet people and you're like, "Hey, how are you? How are you?" And they say something, they try and be interesting, and you try and be interesting back, but in the end you're like, "I don't need to remember that name."

ROBERT: Right, of course. Yeah.

JAD: Gone. Foom!

ROBERT: And then comes along somebody ...

JAD: Yeah, every hundred times, the stars align, the world falls away, things narrow, and you just click.

ROBERT: I know that.

JAD: But do you ever wonder what actually happens in that moment?

LAUREN SILBERT: Like, when you meet someone that you really get. I just—I don't think that there's anything that really feels better than that.

JAD: That's Lauren Silbert. She's a neuroscientist at Princeton. She wonders. She's been wondering for a while.

LAUREN SILBERT: When I was, I don't know, maybe eight, and I used to study with my dad, we would go over things. And I remember, like, I didn't understand this one, like, math problem, and he was explaining it to me, and all of a sudden I got it, and I started to cry. And he got really nervous because I was crying.

JAD: Why were you crying?

LAUREN SILBERT: Because I was so excited that I, like, finally got it. That's my first memory of really, like, being excited about the intensity of understanding.

JAD: So fast forward 20 years, Lauren is at Princeton, and in the basement of her building ...

JAD: Here, can you tell me where we are?

LAUREN SILBERT: We are in the fMRI facilities in Green Hall at Princeton University.

JAD: They've got this giant brain scanner.

ROBERT: Ooh!

JAD: Looks like an airplane engine.

ROBERT: More like a donut.

JAD: Yeah, you could go with donut. And as you know, with the scanner, you can put people in it and have them do tasks, think—think a thought or ...

ROBERT: Sing a song.

JAD: Sing a song, or watch a movie. And then the researchers can see into their brain, you know, without having to cut in there. And Lauren got it into her head, "Could I use this big donut to investigate the clicking question?"

JAD: So is the question when things click, what clicks?

LAUREN SILBERT: What clicks? And if we can know what clicks, can we learn how to make it click more?

JAD: So one day last year, Lauren got into the brain scanner ...

LAUREN SILBERT: I sort of like it in there.

JAD: ... and she told this story.

JAD: Can you just tell me that story?

LAUREN SILBERT: Well, it's a 15-minute ...

JAD: Come on!

LAUREN SILBERT: So—okay, so I told the story ...

JAD: Have I ever actually told you the whole thing?

LAUREN SILBERT: ... without any sort of rehearsal.

JAD: Fully?

ROBERT: I think maybe four—well, 27 times. Something—something under 30, under 30 times.

JAD: [laughs] I'm gonna tell it one more time for everybody else.

ROBERT: Yeah.

JAD: Play along.

ROBERT: [laughs]

JAD: So the story is about her prom. So Lauren is in high school, and this guy that she doesn't really like asks her to go to the prom.

ROBERT: Hmm.

LAUREN SILBERT: Pretty awkward.

JAD: But she's like ...

LAUREN SILBERT: Oh, okay.

JAD: You know, didn't know what to say. Now subsequent to being asked by the first guy, she actually falls for real for a second guy, guy number two. 

LAUREN SILBERT: We just liked each other. Clicked.

JAD: So now she has a situation because she likes the second guy, said yes to the first guy.

ROBERT: And he still wants to be the date, he wants to be her ...

JAD: Yeah, oddly enough, he still wants to go with her. So she ends up going with guy number one.

LAUREN SILBERT: So we get to the prom and ...

JAD: Guy number two, her boyfriend shows up drunk.

LAUREN SILBERT: Very drunk.

JAD: Punches fly, it gets messy. So she drags guy number two, her boyfriend, out to the parking lot ...

LAUREN SILBERT: But on the way to the car, he trips and falls directly on his face.

JAD: Right onto his face?

LAUREN SILBERT: Like, right onto his face.

JAD: On the concrete?

JAD: And he starts bleeding ...

ROBERT: [laughs]

LAUREN SILBERT: Bloody nose.

JAD: ... profusely. So she's like, "Oh, give me your keys, I'm gonna drive." 

LAUREN SILBERT: I'll drive your car.

JAD: And she doesn't have a license, but he can't drive.

LAUREN SILBERT: Right.

JAD: So she drives them both out of the parking lot. A couple minutes later, they come upon an accident.

ROBERT: In the—in the street?

JAD: Yeah, it's right there. Some cars had gotten into a thing. So they're rolling up to it ...

LAUREN SILBERT: I get distracted ...

JAD: ... and she crashes into the accident that had already happened.

ROBERT: [laughs]

LAUREN SILBERT: ... and I'm going very slowly, and it's just that the police were already there

and they, like, watched this.

JAD: So the officer walks up, sees her, no license, sees this dude who's all bloody and messy, and was like, "All right, give me your registration." She thinks she's going to jail, but here is where fate steps in. As the officer is walking back to his car with her registration, a wind ...

ROBERT: A lucky wind.

JAD: ... one of those, kicks up, blows the registration out of the officer's hands. He can't find it, and he has no choice but to let her go.

LAUREN SILBERT: So then I just left. So that was the story that forms the basis ...

JAD: Okay. That is the story that forms the basis of this project. Okay, so now let's rewind.

JAD: So anyhow, she told that story in the scanner, all the while the scanner snapped pictures of her brain moment to moment. Then she got a bunch of other people, put them in the scanner, and had the scanner snap pictures of their brains.

LAUREN SILBERT: As they're listening to the story.

JAD: You with me so far?

ROBERT: Yeah.

JAD: Next, she compared brains.

LAUREN SILBERT: Okay. So here, I can show you.

JAD: Lauren showed us brain scans where she divided each brain into ...

LAUREN SILBERT: ... thousands ...

JAD: ... of tiny little squares.

LAUREN SILBERT: That we call voxels.

JAD: Thousands? 

LAUREN SILBERT: Thousands, yeah.

JAD: Oh.

LAUREN SILBERT: So then what we can do is we can take one voxel in one brain and directly compare it to the same exact voxel in the other brain.

JAD: Shut up! Wow!

LAUREN SILBERT: And we do this across the entire brain.

JAD: And this is where things get interesting. When people really got her story—because she'd run them through all these tests to see if they could remember the different chapters, the words she used ...

ROBERT: She was checking to see how well they listen?

JAD: Yeah, she would have them kind of recall the story.

ROBERT: Okay.

JAD: Some were really good at recalling, others not so much. Now the people that did well, like really well, she found that as they were listening to her story, their brain would literally begin to mirror hers. All the little voxels in their head would start to sync up with all the little voxels in her head.

ROBERT: So they're, so they're just listening like anyone listens. They're just hearing what you're saying. I get that.

JAD: No, no. Let me put it to you a different way: you're right, I mean right now, you and I, our voxels are mirroring each other.

ROBERT: Yeah, vaguely.

JAD: You know, like we're both speaking English.

ROBERT: Yeah.

JAD: So we could assume, say 20 percent.

ROBERT: At least. I would go 23-24.

JAD: Let's say 24, okay? But let's say you bump it up to 30, maybe bump it up to 35. Let's get a little higher, 40, 42, 48, 49 ...

ROBERT: I've never understood you at a 50 percent level.

JAD: But let's say we get to 50 percent, even 60. There's a certain point at which something happens where it's no longer me just describing an experience to you, it's you actually having the experience, you know?

ROBERT: Ah, yeah.

JAD: Like, you know that the difference between explanation and experience is like the Grand Canyon, right?

ROBERT: Yes.

JAD: Well, she's found a way to quantify the gap.

ROBERT: So when I'm sitting there listening to Meryl Streep, I'm all Meryl inside, outside and all around. That's 100 percent Meryl. If you're listening, that's 100 percent Meryl Streep.

JAD: She is not listening to this. [laughs]

ROBERT: You were saying?

JAD: I'll give you an example of what I was just saying.

LAUREN SILBERT: Here, let me show you.

JAD: So while I was in Lauren's office, she showed me this particular slide of her results.

LAUREN SILBERT: So on this side, we have this comprehension rank, and what that means ... JAD: Basically, it was a graph, and on one axis she had how much they actually understood the story and could recall it, and on the other axis, she had how much their brain synced up with hers, which is sort of like how much they experience the story.

JAD: What are these marks, by the way? Are these people? 

LAUREN SILBERT: Yeah. No, sorry about the—wait. These—this is just background ...

JAD: The little Xs.

LAUREN SILBERT: Oh, these are individual subjects.

JAD: I see.

LAUREN SILBERT: So if you take out this one outlier, actually ...

JAD: She pointed to this one subject who was way on one side of the graph.

JAD: So that person is—just didn't get your story at all?

LAUREN SILBERT: No, this person ...

JAD: Actually did understand her story, scored really nice on comprehension, but just didn't sync up with her brain at all.

LAUREN SILBERT: This person—this person—well, so this is a—a little interesting tidbit. [laughs] I know this person.

JAD: You know this person.

LAUREN SILBERT:  I know this person, yeah.

JAD: So that person, I'm almost positive, is her fiance.

LAUREN SILBERT:  Yeah, it was—there were some fights.

JAD: In—in just, or for real?

LAUREN SILBERT:  I mean, for real. I don't think he was actually paying attention. But this one up here ...

JAD: She pointed to another subject all the way on the other side of the graph who was a super brain-coupling master.

LAUREN SILBERT: Was a girl, an undergrad who I had never met before, and her brain coupled with my brain was twice as much as everybody else. I mean, really, just like—I contacted her after because I wanted to, like, have lunch with her and just see if we're the same person or not.

JAD: And?

LAUREN SILBERT: And she never got back to me.

JAD: What?

LAUREN SILBERT: I know. Isn't that crazy?

JAD: Really?

LAUREN SILBERT: Mm-hmm. It was sort of the end of their semester, and I think she might have been away.

JAD: In the weeks after I spoke with Lauren, we emailed a few times and I kept asking her, I was like, "So what about that girl?"

ROBERT: The one who knew everything? Heard everything.

JAD: Yeah, who is she? Like, how do you explain the connection? Is it a connection? Let's go meet her! Come on, come on, come on!

ROBERT: She didn't want to.

JAD: No, she did, actually. And we started referring to the girl in email as "BD."

ROBERT: BD, meaning what?

JAD: Meaning "Brain Double." BD, BD, BD, BD, BD, BD, BD, double, double, double. Anyhow, eventually, after two weeks of constant emailing and searching, BD turns up and agrees to meet. The meeting took place on a sunny Tuesday afternoon at Princeton, and I missed it because I was on the wrong train. When I finally get there, BD had come and gone.

ROBERT: So you never laid eyes on BD?

JAD: I did not. But I talked to Lauren right after she had.

LAUREN SILBERT: It was weird.

JAD: Really?

JAD: We sat down on a bench, and she gave me the scoop.

JAD: Okay, you seem a little shaken.

LAUREN SILBERT:  Yeah, it was a strange experience.

JAD: First thing she tells me is that the mystery girl's name is her name.

LAUREN SILBERT: Lauren. My—my name as well.

JAD: She was Lauren and you were Lauren?

LAUREN SILBERT: Yes, we're both named Lauren.

JAD: Wow. I kind of almost ...

LAUREN SILBERT: I know, it's weird, but there are lots of Laurens out there.

JAD: I know, but still, that's so weird.

LAUREN SILBERT: I feel like ...

JAD: At this point, I'm like, I mean, this is like an Aristophanes whopper here, folks.

ROBERT: [laughs]

JAD: That's what I was thinking, and that's what Lauren told me that she had been expecting, too ...

LAUREN SILBERT: Yeah.

JAD: ... beforehand.

LAUREN SILBERT: I was expecting her to come in and just like be me.

JAD: And when she showed up, was she you?

LAUREN SILBERT: No, not at all.

LAUREN #2: Yeah.

JAD: Earlier, they had met at a coffee shop, and since I'd missed the whole thing, I was very lucky that Lauren number one had recorded the meeting on her laptop.

LAUREN SILBERT: Okay, so I want to know, did you—where did you grow up?

LAUREN #2: I grew up in Vancouver, BC.

LAUREN SILBERT: In Vancouver?

LAUREN #2: Yeah.

JAD: Lauren One's theory was that they would have a common background, or a common something that would explain this symmetry between them, but what you hear is Lauren One looking for points of connection. And, well, listen ...

LAUREN SILBERT: Okay, do you have prom in Canada? Is that a stupid question?

LAUREN #2: Well, we do. I actually couldn't go to mine.

LAUREN SILBERT: You didn't go to your prom?

LAUREN #2: Yeah.

LAUREN SILBERT: Okay.

LAUREN #2: I wish I could have.

LAUREN SILBERT: Did you—did you have, like, significant relationships in high school?

LAUREN #2: No.

LAUREN SILBERT: No, not at all.

LAUREN #2: I went to an all-girls school, so ...

LAUREN SILBERT: You went to an all-girls school? Did you have to wear uniforms?

LAUREN #2: Yeah.

LAUREN SILBERT: Was it like Catholic?

JAD: In the end, there was not one thing they had in common, except their names and Princeton.

ROBERT: You thought that this was going to be, you know ...

JAD: Something. I don't know.

ROBERT: Maybe your premise is wrong?

JAD: What do you mean?

ROBERT: Well actually, I snuck up to Columbia University and I asked a neuroscientist about this.

JAD: When did you do that?

ROBERT: While you were in Princeton, I was on the subway going up to see Joy Hirsch.

ROBERT: Hi.

JOY HIRSCH: Hi. Nice to meet you.

JAD: What? You went behind my back?

ROBERT: What happened is I said to her, "Look, we have this pretty great paper." And she agreed it was a wonderful paper. I said, "It shows these two women who seem to be in such lockstep. Wouldn't you suppose that the two of them, if they ever met, would become friendly?" 

JAD: Or have some connection?

ROBERT: Yeah.

JOY HIRSCH: Would you come to the same conclusion if yours and my heartbeats were exactly the same?

ROBERT: Depends on the circumstances. If it was a beautiful night and a sinking moon in Venice, maybe. [laughs]

JOY HIRSCH: If—you have elaborated the story beyond my question. Say your heartbeat is about 62 beats per minute, say mine was exactly 62 beats per minute, would you say that we were more in sync than if mine was 72 beats per minute, that you and I were more soulmates?

ROBERT: No, probably not. I'd want to, but I don't know if I—you see, I would want to. Don't you want to when you see synchrony between individuals?

JOY HIRSCH: Well—well, yes, but I'm saying that I think that the conclusion doesn't follow from the data.

ROBERT: Joy says it's equally possible that ... 

JOY HIRSCH: …Lauren #2 is just an extraordinarily good listener.

JAD: Hello?

LAUREN #2: Hey. Hey, can you hear me okay?

JAD: Yeah. yeah, I can hear you.

JAD: In fact, when I finally got Lauren #2 on the phone, she did tell me that she is one of those people that when she hears a story, she just falls in.

LAUREN #2: To the point where somebody can be like, "Lauren! Lauren!" And I don't hear it because I'm so focused on the book.

JAD: Yeah.

LAUREN: How do I explain it? So have you ever done any sports?

JAD: Soccer, a little bit, yeah.

LAUREN #2: Do you ever find that sometimes when you're playing soccer, you are so into the game and just reacting or whatever that you kind of lose track of yourself for a little bit?

JAD: Yeah, it's like a dream state almost.

LAUREN #2: Yeah, like a dream state. I definitely have that happen when I'm doing sports, but I also sometimes have that happen when I read.

JAD: Even so, do you think that you and Lauren One will become friends?

LAUREN #2: Um, I honestly probably not.

LAUREN SILBERT: No.

JAD: No.

LAUREN SILBERT: I mean, we're just—it just—I just don't—I wouldn't—I wouldn't. I just wouldn't.

JAD: [laughs] But she's you, but not you. Don't you want to hang out with her? Don't you need to know her?

LAUREN SILBERT: I want to follow her path, but ...

ROBERT: Okay, Jad. Thank you, thank you very much. Why don't you just sit down just for a second? We're going to play a little soft—I think we can just repair all the damage that has just occurred to your sensitive psyche. Just listen and we'll be right back.

LAUREN SILBERT: Hi, this is Lauren.

LAUREN #2: Hey, this is Lauren.

LAUREN SILBERT: Radiolab is funded in part by the Alfred P. Sloan Foundation.

LAUREN #2: Enhancing public understanding of science and technology in the modern world.

LAUREN SILBERT: More information about Sloan at www.sloan.org.

LAUREN #2: Radiolab is produced by WNYC and distributed by NPR.

LAUREN SILBERT: Thanks. Okay, bye.

LAUREN #2: Bye.

JAD: Chirality, take 30.

JAD: Hey, I'm Jad Abumrad.

ROBERT:  I'm Robert Krulwich.

JAD: This is Radiolab, and today we are desperately seeking symmetry.

ROBERT: And thus far, we are failing ...

JAD: Desperately.

ROBERT: Because maybe—maybe, you know, if we took—if we rejiggered our whole approach, because symmetry, you know, is really about ...

JAD: Love.

ROBERT: [laughs] No, it's—it's ...

JAD: What?

ROBERT: No, we're changing the subject now. It's about the way things look when they're flipped around or turned or rotated—and this is where it gets really interesting, reflected.

JAD: Reflected.

ROBERT: Yes, reflected. Because there was a ...

JAD: Reflected.

ROBERT: Yes, there was a mathematician at Oxford University named Charles Lutwidge Dodgson.

JAD: There's a math-y name for you.

ROBERT: Well, he had a different name as it happens.

JAD: What?

ROBERT: Lewis Carroll.

JAD: Oh, like the Alice in Wonderland dude.

ROBERT: The Alice in Wonderland dude. Yeah.

JAD: He was a mathematician?

ROBERT: He was.

JAD: I really didn't know that.

ROBERT: Did you know that he wrote another book called Through the Looking Glass?

JAD: Truthfully, I didn't know they were different books.

ROBERT: You know very little in this particular section of our program.

JAD: [laughs] I really don't.

ROBERT: But there's a part of the book where Alice is standing in her room talking to her cat.

NATASHA GOSTWICK: Now, if you'll only attend, Kitty, and not talk so much, I'll tell you all about my ideas about Looking-Glass House.

ROBERT: This is Natasha Gostwick reading. And in this section of the book, Alice is telling her cat, "Let's take a look at the difference between our world and that world right there in the mirror."

NATASHA GOSTWICK: That's just the same as our drawing room, only the things go the other way. The books are something like our books, only the words go the wrong way. I know that because I've held up one of our books to the glass, and then they hold up one in the other room. How would you like to live in a looking glass house, kitty? I wonder if they give you milk in there? Perhaps looking glass milk isn't good to drink.

ROBERT: Perhaps mirror milk isn't good to drink, she says.

JAD: Why are you talking like that? What does that even mean?

ROBERT: Well you just stick with me on this, I think I will make it perfectly clear.

JAD: Okay.

ROBERT: This is a very, as it turns out, difficult scientific question.

NEIL DEGRASSE TYSON: Yes, they call it chirality.

JAD: Chai-what?

ROBERT: This is Neil deGrasse Tyson.

NEIL DEGRASSE TYSON: Neil, N-E-I-L, deGrasse, small-de, capital G-R-A-S-S-E, Tyson.

ROBERT: He's an astrophysicist with the American Museum of Natural History.

NEIL DEGRASSE TYSON: Also the director of the Hayden Planetarium.

JAD: Cool.

ROBERT: And what is—what is chirality?

NEIL DEGRASSE TYSON: Well, it's when you make a molecule, there's no rule or law that says it has to be symmetric.

ROBERT: Neil says if you zoom into that bowl of milk, what you're gonna find is just chains of atoms that are stuck together in a very particular shape.

NEIL DEGRASSE TYSON: And that shape, it could curl in a particular way. So for example, if you have a spring, and you turn your finger in the direction of the spring ...

ROBERT: This is a spring like a coil? 

NEIL DEGRASSE TYSON: A coil. Like the spring out of your click pen. Pull out that spring.

JAD: All right, I have a pen right here.

NEIL DEGRASSE TYSON: Undo your pen, pull it out.

JAD: I got the spring out. Here we go.

NEIL DEGRASSE TYSON: And look at the way the spring turns and move your finger in the direction it turns.

JAD: Moving my finger, it's turning clockwise. All the way up to the top.

NEIL DEGRASSE TYSON: Okay, that spring is that way in—in its life.

ROBERT: Whether it's right side up or upside down.

NEIL DEGRASSE TYSON: Doesn't matter.

JAD: Always clockwise.

ROBERT: But if you had a mirror, Jad, do you happen to have something?

JAD: Do I have a mirror? No.

ROBERT: Or—or take your phone, which has a reflected shiny thing.

JAD: Okay.

ROBERT: Put your spring in front of the shiny surface of the phone, trace the spring with your finger and tell me which direction is your finger going?

JAD: Clockwise.

ROBERT: No.

JAD: We already did this.

ROBERT: In the reflection.

JAD: Oh, in the phone, it's kind of hard to tell. It's going the opposite way.

ROBERT: Yes.

JAD: Counterclockwise!

NEIL DEGRASSE TYSON: Exactly. And so now you have two oppositely-turned springs. You cannot turn one into the other. They're built differently, yet they are curiously identical. So since molecules are just sequences of atoms, imagine a molecule that has that shape.

ROBERT: If you put that molecule in front of a mirror, just the same as the spring, you've got now two molecules built differently but curiously identical. Kind of like your right hand and your left hand.

MARCELO GLEISER: Your left hand and your right hand are related by a mirror image. It's the same thing with these molecules.

ROBERT: This is Marcelo Gleiser, he's a physicist.

MARCELO GLEISER: At Dartmouth College.

ROBERT: And according to Marcelo, this is how scientists talk about molecules. They call them righties, they call them lefties.

MARCELO GLEISER: Sometimes we call it handedness. Sometimes they get a little more fancy, and we call it chirality because chiral "chéri" in Greek means "hand."

ROBERT: And Marcelo says if you look at pebbles or granite or cement, inanimate stuff, when you look at the shape of things inside, it's a mixture of the two.

MARCELO GLEISER: 50 percent left-handed, 50 percent right-handed.

ROBERT: However ...

MARCELO GLEISER: If you look at all the proteins of living things, they're always left-handed and not right-handed at all.

JAD: Really?

NEIL DEGRASSE TYSON: Life has chosen one over the other. Life, as we know it, has ...

JAD: You mean when scientists look inside of living things they—they always see the molecules are pointing one way?

NEIL DEGRASSE TYSON: Yeah.

MARCELO GLEISER: Right. So somehow—and this is what's really amazing, somehow life is choosing a very specific shape for the molecules to make up stuff.

NEIL DEGRASSE TYSON: That's correct.

ROBERT: When you say "life has chosen," let's take that sentence apart. Life, meaning everything that is—that we know of on Earth, every living thing.

NEIL DEGRASSE TYSON: Hence my phrase, "life as we know it."

ROBERT: Everything.

NEIL DEGRASSE TYSON: That's what that means.

ROBERT: The littlest things to the blue whale.

NEIL DEGRASSE TYSON: That would be as we know it.

ROBERT: The littlest, tiniest thing to the tree, the biggest tree, the giant sequoia.

NEIL DEGRASSE TYSON: That would be as we know it.

MARCELO GLEISER: Every protein in you, dogs, trees, you name it ...

JAD: Is it filled with left-handed building blocks?

MARCELO GLEISER: Yes, it's called the chirality of life.

ROBERT: The chirality of life. Life, my friend, is left-handed.

JAD: Hmm, that's pretty, that's—well, it feels cool. But let me just—like, so what?

ROBERT: [laughs]

JAD: I mean, I don't want to put it bluntly. But I mean, like ...

ROBERT: Well, other than the sheer surprise of having everything in life being shaped in one direction?

JAD: No, I mean it is surprising, but I mean, what does it have to do with my life, anyone's life, or the mirror thing?

ROBERT: Well, this brings us back—this brings us back to the mirror mystery and Alice and the mirror milk.

JAD: No.

ROBERT: No?

JAD: Because—because you just told me that the milk is left-handed because milk is an organic thing.

ROBERT: From a living cow, yeah.

JAD: Remember you said that? Life is lefty?

ROBERT: Mm-hmm.

JAD: So there can't be any right-handed milk. So the mirror milk doesn't exist.

ROBERT: Well, that's because I forgot to tell you that scientists all the time manufacture mirror molecules.

JAD: They do?

ROBERT: Yeah. Yeah, they go into their laboratories and they synthetically make mirror molecules of all kinds of things.

JAD: Can they do milk? Mirror milk?

ROBERT: I don't know about milk in particular, but I do know that when I talked to an Oxford professor, Marcus du Sautoy, he told me ...

MARCUS DU SAUTOY: If you take the atoms which built caraway seeds ...

ROBERT: Which is the spice they use in rye bread.

MARCUS DU SAUTOY: ... take a mirror image of them, suddenly you get something which tastes of spearmint.

JAD: Huh!

MARCUS DU SAUTOY: It's what's put on Wrigley's spearmint gum. And in fact, there are some very dramatic examples of this, not just where the taste changes but listeners might remember a story about the thalidomide drug.

[NEWS CLIP: In 1958, a West German pharmaceutical firm began marketing a new drug.]

ROBERT: This is a news spot from the early 1960s.

[NEWS CLIP: A sedative so effective and apparently harmless, it quickly became one of the most widely used and prescribed drugs in West Europe: thalidomide.]

ROBERT: Before long, pregnant women started taking it as a way to calm morning sickness. And most of us, well, we know what happened next.

[ARCHIVE CLIP, John F. Kennedy: Every woman ...]

ROBERT: President Kennedy in a press conference ...

[ARCHIVE CLIP, John F. Kennedy: ... in this country, I think, must be aware that it's most important that they do not take this drug, that they turn it in. Every citizen, of course, should be aware of the hazards.]

ROBERT: All in all, more than 12,000 children were born with arms and legs that were shortened or deformed or completely missing. The strange thing, according to Marcus, is that we now know that when they first made thalidomide, it was all one-handed. Let's say it was left-handed ...

MARCUS DU SAUTOY: Yeah, and it did actually cure morning sickness.

ROBERT: And was completely harmless. But somewhere along the way, thalidomide flipped. We don't know whether this was in the drug-making process or after, but we do know ...

MARCUS DU SAUTOY: Its mirror image was incredibly poisonous.

ROBERT: So you know what this means, Jad?

JAD: What?

ROBERT: That in a show about symmetry, what we've just discovered is that life itself is actually deeply asymmetric.

JAD: Yeah.

ROBERT: Unlike love, where we started the program back with Aristophanes, when it comes to life you don't want to meet the other half.

JAD: Stay away, mirror milk! Stay away!

ROBERT: That's—well, enough about mirrors.

JAD: No, no, no. No, no. I think we can take this another step further.

ROBERT: There is no further step to take.

JAD: No, there is. Because I mean, because something about this chemistry reflections thing resonates for me with the actual experience of standing in front of a mirror.

ROBERT: How?

JAD: Well, you know, when you look at that guy, and you're like, "Yeah, ooh." I mean, we talked about this on stage, actually, in DC at the Shakespeare Theatre. Remember when I asked you that personal question?

ROBERT: Oh, yeah. Do you want to do that?

JAD: Oh, yes we do.

JAD: Psychologically, let me ask: psychologically, do you—do you enjoy looking in the mirror?

ROBERT: Is that a question you want to ask me in front of—that's a private question, I feel.

JAD: Surely you know though, that you're—the difference between your true self and your mirror self is not trivial.

ROBERT: My true—what do you mean by my true self? I don't under ...

JAD: Well, I'm gonna tell you a story now about a guy named John Walter.

ROBERT: Oh, the—with the little mustache from Baltimore, from the movies?

JAD: No, that's John Waters. Walter. He's a computer programmer in New Rochelle. Paid him a visit recently because, back when he was in college, he sort of kind of switched places with the guy in the mirror.

JOHN WALTER: It—it was many years ago.

JAD: How old were you?

JOHN WALTER: I was 19.

JAD: 19.

JOHN WALTER: So it was a long time ago.

JAD: We're talking late '70s here. 

JOHN WALTER: But I was—I had already had some issues with the mirror.

JAD: So let me set this up for you. The thing to know about John is that as a kid he had a tough time. Like so many of us, he would get bullied, beaten up on the playground. It was no better when he got into his teens, and as a 19-year-old, his social life consisted of a series of stinging humiliations, like the following.

JOHN WALTER: I remember at the time there was a lot of kids hanging out. You know, there was a crew of people, like, you know, 20, 30, 40 kids would gather together at the aqueduct, beautiful woods of the aqueduct, and go drink beers and smoke cigarettes, you know? I walked into the group, like, "Hey, what's up?" And it's like, "Yeah, whatever." Roundly rejected.

JAD: And that, according to John, was ...

JOHN WALTER: Normal.

JAD: That—that was normal for you. Normal.

JOHN WALTER: Very normal. Like, people would say, "What's that guy doing here? Eww!"

ROBERT: Maybe he was, like, wearing the wrong the plaid pants or had, like, you know, mismatched socks. There might be some ...

JAD: Whatever. Don't you empathize ...

ROBERT: Of course.

JAD: ... empathize with this guy?

ROBERT: Nobody wants to be 19 and be the yucky person. Of course I would empathize.

JAD: …however, the story that will follow centers on a revelation that John had that began just as he was about to start his summer job.

JOHN WALTER: For Con Ed. I was working for them.

JAD: As a painter.

JOHN WALTER: And I had some pictures taken for Con Ed.

JAD: These were ID photos that you had?

JOHN WALTER: Yeah, it was an ID camera that had four lenses, so when they took the negative, there was four of me: boom, boom, boom, boom.

JAD: Like little squares?

JOHN WALTER: Little squares. And I remember looking over and—and going, "Why do I look so weird? Why do I look so weird?"

JAD: “Why do I look so weird?” Because here's the thing: I mean, the John in the pictures was not the John that he knew himself to be. That John was kinda timid.

JOHN WALTER: Nerdy.

JAD: Not cool.

JOHN WALTER: Why do I look so weird in pictures? I look fine.

JAD: What do you mean you look fine? How do you know you look fine?

JOHN WALTER: Well, I thought I looked fine in the mirror, you know, when I looked at myself.

JAD: Of course in the mirror, things on the left go to the right, things on the right go to the left.

Wait a second. That's when it hit him.

ROBERT: What—what hit him?

JAD: It's the hair part.

ROBERT: It's the what?

JAD: It's the hair part.

ROBERT: It's the what?

JAD: It's the hair part. I could do this all night! It's the hair part.

ROBERT: What does that mean? It's the—I hear you, I hear you. What does that mean, it's the hair part?

JOHN WALTER: Well, in the picture, I saw a guy with a right hair part, and in the mirror I was seeing a guy with a left hair part.

JAD: Essentially, John ...

ROBERT: Wait, which part—which side of my hair parted on is this?

JAD: Your left, your left.

ROBERT: My left, okay.

JAD: Now John thought he was a lefty too. He would stand in front of the mirror, and the mirror would tell him he was parting it to the left, but in fact he was parting it to the right in real life. Now the lefty guy in the mirror, he liked that guy.

JOHN WALTER: I was fine with that guy. He was cool. He was—there was nothing wrong with him.

JAD: But he realized he was the only person seeing that guy, so he thought ...

JOHN WALTER: Oh, let me put my hair on the other side.

JAD: "Let me essentially swap real me for mirror me."

JOHN WALTER: It was one of these things where, "Yeah, that looks really weird in the mirror, but I bet you it looks good in real life. Let me go find out."

ROBERT: [laughs]

JAD: So what did you do?

JOHN WALTER: Well, that night ...

JAD: He goes back to the aqueduct, the same posse is there as before.

JOHN WALTER: I mean, that same group interestingly enough, they had beat the crap out of me like three years earlier when I was in, like, ninth grade.

JAD: But there he was, now with his hair parted on the left. He says this time ...

JOHN WALTER: Things were different.

JAD: Somebody offered him a beer.

JOHN WALTER: I was like, wow! But the thing that I knew made it better was when I left, I got goodbyes.

ROBERT: This is ridiculous that you would tell me a story about a man who is having social failures universally, shifts his hair over, and is remade. This is like ...

JAD: Look, it's his experience. It's very—this is very easy to dismiss. But I'm gonna win you over.

ROBERT: Yes, very easy.

JAD: Are you ready? I'm gonna win you over! Are you ready for this? I don't think you're ready. Are you ready?

ROBERT: Are you asking me to be broad minded?

JAD: I'm gonna—I'm gonna show you a picture right now.

ROBERT: All right.

JAD: Okay, have a look at ...

ROBERT: Okay. At?

JAD: Who is that?

ROBERT: It's Abraham Lincoln.

JAD: Our 16th President, Abraham Lincoln. Now just stare at him, Robert. Take him in, take him deep into your consciousness.

JAD: By the way, this next part, you can see this picture at Radiolab.org. It's worth checking out.

JAD: His eyes, his nose, his mouth. Pay attention particularly to the hair part, okay? Now look what happens when you flip Abraham.

ROBERT: [gasps] Oh that—wait, wait, no, no, no, no, no, no. Is this the same picture?

JAD: It's the same picture.

ROBERT: Go back to the other picture. Go.

JAD: All right. There's Abe.

ROBERT: Now do the other one. [gasps] Whoa!

JAD: You see?

ROBERT: That's so weird!

JAD: Now here's the thing: this is what Abraham Lincoln would have seen when he looked in the mirror. He would have seen this guy, not the other guy, the one we all see.

ROBERT: Huh!

JAD: So there's something going on here. Would you not at least acknowledge me that ...

ROBERT: I find this vaguely plausible, yes.

JAD: ... something's going on here. Okay, with your permission, Mr. Cynic, I will now rejoin John.

ROBERT: Who's about to, what, get married and have three babies because his hair ...

JAD: He says after—after he switched his part ...

JOHN WALTER: It just kept getting better and better and better all summer long.

JAD: He was suddenly invited to all of these parties by the very same people who used to beat him up. And for the first time, he says ...

JOHN WALTER: I was clearly one of them.

JAD: Now whether or not you buy that this is in fact because of his hair, that's on you, okay? But let's fast forward just a little bit ...

JOHN WALTER: The next summer ...

JAD: This would have been 1979?

JOHN WALTER: Yeah, 1979.

JAD: John's sitting in front of the TV, and on comes ...

[ARCHIVE CLIP, Jimmy Carter: Good evening, this is a special night for me.]

JAD: ... the President ...

JOHN WALTER: Jimmy Carter.

JAD: ... making a speech about how our nation is in a deep funk.

[ARCHIVE CLIP, Jimmy Carter: Why have we not been able to get together as a nation to solve our serious energy problem?]

JOHN WALTER: The Malaise Speech, you know, that—that infamous "Country is in malaise."

[ARCHIVE CLIP, Jimmy Carter: It's clear that the true problems of our nation are much deeper, deeper than gasoline lines or energy shortages, deeper even than inflation, or recession.]

JAD: Now as you know, I'm sure you remember, a lot of people would criticize Jimmy Carter for making this speech because he's up there admitting flaws, and they were like, "C'mon, Mr. President, don't be weak. Man up!" John, meanwhile, is sitting in front of the TV and he's thinking ...

JOHN WALTER: Dude, you gotta change your hair part.

[audience laughs]

JOHN WALTER: And so I wrote him.

JAD: You wrote to him?

JOHN WALTER: I wrote to him.

JAD: Wait, wait. So you said ...

JOHN WALTER: I—I think I just said, "I think you should change your hair and part it on the left. I did myself, and found it to be much more powerful, much more successful." And then about six ...

JAD: Do you have that letter?

JOHN WALTER: I so wish I did. I don't have it. And then about six weeks later, boom, he switched.

JAD: He switched!

ROBERT: No, he didn't!

JAD: John wrote him a letter, and President Carter switched.

ROBERT: No!

JAD: It might not have been John's letter that did it.

ROBERT: No, no. You have no evidence.

JAD: Think about how much—what's involved in a president switching his hair. There are focus groups, there are prayer meetings, there is so much thought that goes into it.

ROBERT: Did anyone actually record this?

JAD: Yes!

ROBERT: They did?

JAD: I will—I will now read you a journalistic account from no—a periodical—Washington, you see it right there? You see? Bam, right there.

ROBERT: Oh, man!

JAD: Newsweek, May 7, 1979: "At first, photographers thought they had their negatives reversed, but no, Jimmy Carter has changed the part in his hair from the right side to the left. The Washington press corps demanded an explanation."

ROBERT: But remember that, you know, as opposed to John, who changes his hair and then all the girls give him beers, this guy, he was running against a luxuriantly-haired man, Ronald Reagan, and it didn't matter. He just you know, he got crushed.

JAD: You know what? Forget—forget the Executive Branch. Stay with me now.

ROBERT: Yes. Yes.

JAD: I was with John, and he was showing me pictures of congressmen and of celebrities and I noticed something peeking out at the bottom of the pile.

JAD: I see peeking out underneath the stack of photos is a Superman.

JOHN WALTER: Yeah.

JAD: He showed me a picture of Superman looking mighty in his suit. Notice how he parts his hair?

ROBERT: Yeah, it's a little bit on there, on that side. Yeah.

JAD: Now ...

JOHN WALTER: This is Clark Kent, with him on the right.

ROBERT: Ah!

JAD: And as we know from the movies, Clark Kent is bumbling, sort of dork.

[ARCHIVE CLIP, Superman: I mean—I was at first really nervous about tonight.]

JAD: So somebody who made that movie, maybe explicitly, intuitively understood something about the difference. That, you know, the right part said one thing about Clark Kent, the left part said something about Superman. In fact, there is a scene in the movie where Clark Kent's running down an alley, he's about to turn into Superman, he pulls his shirt open to reveal the "S," and literally mid-stride, his hair goes—fwip!—and turns from the right to the left. So ...

ROBERT: You're saying that sophisticated popular cultural motion picture manufacturers and at least two presidents have been persuaded to this position?

JAD: At this very moment on a Saturday night that is what I am saying.

ROBERT: Oh, all right. Well, for argument's sake then, what would you say—I hate to get into this any deeper—explains the difference between putting the part of your hair on the left hand or the right hand?

JAD: Well, if you ask John what he'll say that the left hair part emphasizes strength and logic because it draws your attention to the logical, more masculine side of your face, your brain, 'cause it's a left-brain kind of thing. But I—I don't really know.

ROBERT: Okay.

JAD: So I decided I would actually take this seriously and figure out how to feel about it. So I called up this guy.

MIKE NICHOLLS: G'day, Jad. It's Mike.

JAD: His name is Mike Nicholls.

ROBERT: Oh, from The Graduate. There's a Mike Nicholls.  Very good.

JAD: No, a psychology professor in Australia. An expert in symmetry.

ROBERT: That Mike Nicholls. Okay.

JAD: I ran him through John's theory.

JAD: Have you ever seen the Superman movies?

MIKE NICHOLLS: Some of the earlier ones, I think.

JAD: You know how Clark Kent's hair is parted to the right?

JAD: So I ran through the whole thing, you know Clark's on the right, maybe he's weak, Superman's left, means he's stronger, more assertive.

MIKE NICHOLLS: Right.

JAD: Is there anything to that, anything at all?

MIKE NICHOLLS: Um, yeah. I mean possibly, you know? Now that's—I—I'll have to ...

[audience laughs]

JAD: But—but he did say this, which is interesting, in focusing on the left, John may be picking up on a particular bias that we human beings have to our left side. For instance, here's an experiment that he and his colleagues did.

MIKE NICHOLLS: Take a snapshot of a person's face at baseline when they're showing no emotion.

JAD: Blank face.

MIKE NICHOLLS: And then get them to try to look as happy or sad as they could.

JAD: Take happy guy and overlay him onto no expression guy.

MIKE NICHOLLS: And almost like a contour map, you could actually look at the amount of change, the amount of muscle movement that had occurred.

JAD: What you will see if you measure the muscle movement in millimeters, on each side of the face you'll see that the smile curves a few extra millimeters on the left side of the face. He says this is nearly always the case, always on the left side.

MIKE NICHOLLS: What it's really telling you is that when somebody smiles or they frown or whatever, they're doing it slightly more strongly on the left side of their face.

JAD: Now if this is the case that our left side is sort of saying more emotionally than our right side, then if you think about the mirror, it's kind of a discombobulating thing, you know, because it's taking your left, which is sort of broadcasting emotion, flipping it to your right, you're seeing yourself, you're all mixed up. You don't know which part of you is where.

ROBERT: You—so you're saying, like, because I tend to address you as my attention on your left side, unbeknownst to me, and your left side is actually flipped over to your right side, I don't—it's a "Where are we" sort of question.

JAD: It's—exactly. But John has developed a solution to this problem.

JOHN WALTER: Let me take this one apart.

JAD: He now makes and sells his very own special mirrors right out of his home.

JAD: And is this where you make the mirrors?

JOHN WALTER: Yeah. Everything that goes into the mirrors is made here. You see here, this is the machine that cuts the mirror.

JAD: He buys these giant sheets of reflective glass ...

JOHN WALTER: And ...

JAD: ... and he slices them into little pieces.

JOHN WALTER: Clunk. And then I snap it.

JAD: Now for each mirror, this is the key: he uses two pieces of mirror glass instead of one? What he'll do is he'll take these two pieces and he'll place them together at—at right angles.

JOHN WALTER: Two mirrors at right angles.

JAD: Like, exactly at right angles.

JOHN WALTER: It has to be 90.00 degrees. And let's just push this up a little bit. That's still not enough.

JAD: In any case, when he finally gets it right—which can take hours—what he'll have is this V-shaped mirror. He'll stand it up, put it in a box, and then voila! What you have is a mirror that shows you a mirror image of a mirror image of you. Takes the normally-flipped guy that you'd see in a mirror, re-flips him so that what you are seeing is essentially, well, for the first time in a mirror, you see yourself as other people see you.

JOHN WALTER: Okay, so there you go.

JAD: So what is this that you have in your hand here?

JOHN WALTER: This is—this is a true mirror. This is a—the 12-inch model. And so when you, like ...

JAD: So this is actually what I look like?

JOHN WALTER: Yeah, touch your right eye. See? It's actually on the right side.

JAD: Oh my God!

JOHN WALTER: Isn't that crazy?

JAD: That's crazy!

JAD: It is surprisingly weird to see yourself this way.

JAD: I feel like my nose is going the wrong way.

JOHN WALTER: Yeah.

ROBERT: [laughs]

JAD: I never knew my nose went that way. And this little flare in my eyebrows is on the wrong side—or the right side, as it were.

JAD: John claims that many a fair number—and I probably would put you in this bunch, my co-host—when they stand in front of this mirror, they ...

JOHN WALTER: Freak out, many of them, because they—it's just their perception is shaken up a little bit.

JAD: In fact, he sometimes takes his mirrors to these festivals, and he'll sort of set them up and have people look at themselves and then fill out comment cards afterwards.

JOHN WALTER: You know, I mean, if you look at some of the comments, you know, it's like ...

JAD: I am a [bleep] monster in your mirror.

ROBERT: [laughs] What did he say?

JAD: I am a [bleep] monster in your mirror. [laughs]

ROBERT: [laughs]

JAD: To break we go. If you want any more information on anything you heard, go on our website, Radiolab.org.

ROBERT: Or if you want to see those incredible pictures of Abe Lincoln, that's where they are.

JAD: That's right. And subscribe to our podcast there as well.

[LISTENER: Hi, this is Eleanor Womack from Brooklyn, New York. Radiolab is supported in part by the National Science Foundation and by the Alfred P. Sloan Foundation, enhancing public understanding of science and technology in the modern world. More information about Sloan at www.sloan.org.]

JAD: Okay. Hey, I'm Jad Abumrad.

ROBERT: I'm Robert Krulwich.

JAD: This is Radiolab. And today ...

ROBERT: We're still desperately looking—seeking symmetry, as you say.

JAD: Yeah. No—not well.

ROBERT: We have looked at love ...

JAD: Failed.

ROBERT: Looked at brains ...

JAD: Failed.

ROBERT: Looked at mirrors ...

JAD: Failed.

ROBERT: The chemistry of life ...

JAD: Failed.

ROBERT: So we thought, well, for the last stop on this trip, if we were to go anywhere to find or look for deep unity, a deep oneness, and symmetry, maybe ...

JAD: The beginning.

ROBERT: Yeah, of everything.

JAD: Moment zero.

ROBERT: So we found ourselves a physicist. Again, it's Neil deGrasse Tyson. I began with a very, very basic question.

ROBERT: If you look at me and I look at you, and you seem to be made of stuff, and I seem to be made of stuff, and here we are, and here are tables, and chairs, is it a surprise to you, in some deep way, that we are all here, made of stuff?

NEIL DEGRASSE TYSON: Yes, it's not so much—surprise understates it. It's shocking, really. It's shocking.

ROBERT:  Huh.

JAD: What is—what is shocking?

NEIL DEGRASSE TYSON: That there's any matter in the universe at all.

JAD: Meaning that this conversation shouldn't be happening?

NEIL DEGRASSE TYSON: No, it's way deeper than that—thank you. It's deeper than just whether or not we'd be having this conversation now. It's whether or not any of this would exist—Earth, the galaxy, and the like.

MARCELO GLEISER: Okay, so if you go back 13.7 billion years ago ...

ROBERT: That's Marcelo Gleiser again, the physicist. And he says if you roll back the history of the universe ...

MARCELO GLEISER: No more stars, no molecules, no atoms. If you played the movie backwards now ...

ROBERT: All the way to the beginning.

MARCELO GLEISER: Just after ...

ROBERT: You know ...

MARCELO GLEISER: ... the Big Bang, you have what we call a primeval soup.

ROBERT: This soup was—it actually was made of light.

NEIL DEGRASSE TYSON: A universe of light with very high energy.

MARCELO GLEISER: And out of this energy, this heat, these interactions …

ROBERT: You suddenly get ...

[belching sounds]

JAD: What the hell is that?

ROBERT: These are belches, Jad.

JAD: Belches?

ROBERT: Belches of matter.

JAD: The light is doing this?

NEIL DEGRASSE TYSON: Yes. This is what E=mc² is all about.

ROBERT: Because energy is just a form of matter.

NEIL DEGRASSE TYSON: And vice versa.

JAD: I feel like I should know what you're talking about, but I don't. 

NEIL DEGRASSE TYSON: Okay, let's start—let's start a little simpler. There's light all around us. We're in a studio, it's visible light. So this light has no mass, has energy.

JAD: E but no M.

NEIL DEGRASSE TYSON: Mm-hmm. Crank up the energy of the light, go to ultraviolet, x-rays, and there's a point in x-rays where you have a high enough x-ray photon, it will spontaneously turn into a particle—electrons, in fact.

JAD: Oh, so you're saying if you crank up the E, the energy of the light high enough, it'll suddenly just turn into mass?

NEIL DEGRASSE TYSON: That's correct.

ROBERT: So Jad, just picture the soup, really intensely hot, and it's belching out matter.

MARCELO GLEISER: Electrons, zooming around.

ROBERT: Photons.

MARCELO GLEISER: Sparks.

ROBERT: Neutrons.

MARCELO GLEISER: Neutrinos.

NEIL DEGRASSE TYSON: Continuously churning, churning, churning.

ROBERT: Over time, all that matter clumps together in more and more complex forms until you finally get us. Sounds very simple, doesn't it, Jad?

JAD: Yes, but there's a but coming. I can smell it.

MARCELO GLEISER: But—and here's the big but ...

JAD: Knew it.

ROBERT: Back in ...

MARCELO GLEISER: 1928, 1929 ...

ROBERT: ... there was this physicist ...

MARCELO GLEISER: Really young guy, Paul Dirac.

ROBERT: Paul Dirac. He's doing some math, and he's thinking about this whole business of turning light into matter.

JAD: Okay.

ROBERT: Now he's puzzled by something.

JAD: What?

ROBERT: There is a law in physics called the Law of Conservation of Charge, which simply means this:  if you ...

JAD: My, how it rolls off your tongue quite nicely.

ROBERT: Doesn't it?

JAD: It does!

ROBERT: So here's what it means.

MARCELO GLEISER: Whenever you create something, if at the beginning, you have zero electric charge at the end you have to have zero electric charge too. That is, you cannot create electric charge, you have to keep the balance.

ROBERT: If you make something in the universe that has a positive charge or a negative—like, make an electron. Okay, just make one.

JAD: Right now?

ROBERT: Yeah.

JAD: Gone!

ROBERT: That electron has a—you may remember this from eighth grade, a negative ...

JAD: Negative one, baby!

ROBERT: Make—make two electrons. There you go. Now make three electrons.

JAD: Negative three.

ROBERT: Now if the universe is to stay in balance, you need to have something that has a positive charge. You've got three minuses on one side, you have nothing on the other side.

JAD: Wait a second, if this is true, how would you even make an electron? The sheer fact of creating an electron puts it out of balance.

ROBERT: Well, here—here's the solution.

JAD: The fundamental story here is wrong.

ROBERT: Here's—well, no. Paul Dirac thought, well, how about this? What if every time you created an electron, you created an anti-electron? [laughs]

JAD: What?

ROBERT: Every particle could have an equal but opposite antiparticle.

MARCELO GLEISER: That is, a particle that looks very much the same, but essentially, its electric charge is reversed.

JAD: It would look the same? Like, really look ...

NEIL DEGRASSE TYSON: Yes, you'd have to measure their properties to know that they were different.

ROBERT: Is it a mirror image?

NEIL DEGRASSE TYSON: You might think of it as a mirror image. There's a thing called quantum spin, and it would be spinning the opposite way. But charge is the most obvious difference.

MARCELO GLEISER: For example, the antimatter cousin of the electron ...

ROBERT: Because the electron has a negative charge, this little guy should have a positive charge.

MARCELO GLEISER: Exactly.

JAD: But in every other way, it would be the same.

MARCELO GLEISER: Right, and ...

ROBERT: But no one had ever seen one. He just thought that there probably would be one?

MARCELO GLEISER: Yes.

JAD: And why did he think this?

MARCELO GLEISER: Math.

JAD: Math.

MARCELO GLEISER: Math. It was a solution to these equations, and that's the beauty of theoretical physics. By solving equations, you can sometimes find out about the world. And then, yes, a few years later ...

NEIL DEGRASSE TYSON: Ba-da-bing!

MARCELO GLEISER: They found the positron.

NEIL DEGRASSE TYSON: The antimatter version of the electron.

JAD: Ooh!

NEIL DEGRASSE TYSON: Yeah. No, it's deep, it's deep.

ROBERT: How did they do that? Like ...

JAD: Did they actually see it?

MARCELO GLEISER: Well, particles, you know, they're very tiny, right? You can't really see them. So what you do is you create little systems in the laboratory. You get like a vapor ...

JAD: And you put the vapor in a tank, he says. And when the electron or the antielectron shoots through the vapor ...

MARCELO GLEISER: The particle destabilizes the vapor and makes little bubbles, okay? You can see these little bubbles appearing out of nothing.

JAD: Wow! Seriously?

MARCELO GLEISER: It's really an amazing thing. 

JAD: So you can't see the particle itself, but you can see its shadow?

ROBERT: It's—it's road trip.

MARCELO GLEISER: It's road trip, yeah.

JAD: So then he says okay, imagine you get this little piece of light and you heat it up really hot so that it spawns—well, as we learned, not one particle but two ...

NEIL DEGRASSE TYSON: Matter-antimatter pair.

JAD: Put them in the vapor tank ...

MARCELO GLEISER: And if you put a magnet in there, you can tell if it's going to the left or to the right, if it's a positive or a negative charge.

ROBERT: Oh, very clever!

JAD: Oh, how cool!

MARCELO GLEISER: It is cool.

NEIL DEGRASSE TYSON: You see two particle tracks that each curl opposite directions, and if they have the same rate of curl ...

ROBERT: Yeah?

NEIL DEGRASSE TYSON: That means they have the same mass.

JAD: So if we go back to our picture of the early universe of the soup, which—and you named all of those particles, does that mean that for every particle that you named, there is its opposite floating around there as well?

MARCELO GLEISER: Exactly. You have electrons ...

ROBERT: Anti-electrons.

NEIL DEGRASSE TYSON: Neutron-antineutron.

MARCELO GLEISER: Proton-antiproton. This is all very beautiful and you would say, great, I have a very democratic universe, you know, as many particles and antiparticles, and everybody's happy. Only problem is the following: when an electron and a positron meet ...

NEIL DEGRASSE TYSON: They will find each other ...

MARCELO GLEISER: And, uh-oh ...

NEIL DEGRASSE TYSON: And they will annihilate.

ROBERT: What do you mean they'll find each other, because they'll find their original other half?

NEIL DEGRASSE TYSON: No, no, they wouldn't need to.

ROBERT: They'd just find another kind?

NEIL DEGRASSE TYSON: That's correct. That's correct.

ROBERT: So Jad, now imagine that we're in the very early universe. I am a teeny bit of matter and you, my opposite ...

JAD: I'm an anti-Krulwich.

ROBERT: An Anti-Krulwich. And so the particle, which is sitting here and I see you across the haze. Now I'm positive charged, you're negative charged. Opposite charges attract. Attract. Attract.

JAD: And we are zooming together. Here we come. [screams]

[explosion]

ROBERT: You see, it doesn't work out too well for us. But, you know, wait, wait, wait, this is actually a rather profound puzzle, because if Paul Dirac was right, and half the universe is matter, the other half the universe is antimatter, and we all bump into each other as we just did, well ...

JAD: Eventually, I guess we would just not—we would just become—I don't—well, I don't know. Hmm.

MARCELO GLEISER: We would not be here then.

ROBERT: You just blink out and there'd be nothing.

MARCELO GLEISER: Exactly.

JAD: Really nothing? So it's a field of ...

MARCELO GLEISER: Mostly, nothing. Mostly just radiation—radiation—radiation—radiation—radiation—radiation—radiation.

NEIL DEGRASSE TYSON: It's shocking—it's shocking—it's shocking—it's shocking—it's shocking.

ROBERT: Well, there's something wrong with this theory because we're talking to each other, and we're ...

JAD: Exactly.

ROBERT: So something—something's wrong with this notion.

MARCELO GLEISER: Yes, and what's wrong is an imperfection in the laws of physics that we know of now, and that is responsible for this bias.

ROBERT: Which means what? There was—that there was a little more of—of matter, what we call matter, than antimatter or ...

MARCELO GLEISER: Yes. There was, to be precise, to every billion particles of antimatter, we had a billion and one particles of matter.

JAD: Oh my God, really?

MARCELO GLEISER: Yes.

JAD: Wow!

MARCELO GLEISER: And that tiny excess of one in a billion is enough to create everything that exists now.

JAD: One lone little guy!

NEIL DEGRASSE TYSON: We would call that an asymmetry.

ROBERT: So everything we see in the universe, all the stars, all the suns and the moons, and the grass and the mountains and us, all that, we're the left—we're the extra stuff?

NEIL DEGRASSE TYSON: Yes.

MARCELO GLEISER: We are the result of this asymmetry.

ROBERT: Has anybody dealt with the real question that's provoked here? It's like, why was there more of one stuff, kind of stuff than the other kind of stuff?

MARCELO GLEISER: So there you go. That is one beautiful question, but we don't have any—any final answer yet.

JAD: You don't know?

MARCELO GLEISER: Because you see, you don't know. We do not know, that's—which is okay. Not knowing is a wonderful thing in science, otherwise, you could just retire.

ROBERT: [laughs]

NEIL DEGRASSE TYSON: Can I tell you my favorite lawyer joke, told to me by a lawyer?

ROBERT: Yeah.

NEIL DEGRASSE TYSON: I have to, like, spread this because it's the best one: 98 percent of lawyers give the other two percent a bad name.

ROBERT: [laughs]

JAD: [laughs]

JAD: Well, that's the go music.

ROBERT: The go music, meaning go away.

JAD: Meaning us. Or here's a different place to go, to our website Radiolab.org, where you can read more about anything you heard in this hour. You can see those amazing Lincoln pics and other things we've got there on symmetry. And of course, you can subscribe to our podcast.

ROBERT: Which means you get to hear the show, you know, whenever you like.

JAD: I'm Jad Abumrad.

ROBERT: I'm Robert Krulwich.

JAD: Thanks for listening.

[NEIL DEGRASSE TYSON: Radiolab is produced by Jad Abumrad and Brenna Farrell.]

[LAUREN SILBERT: Our staff includes Ellen Horne, Soren Wheeler, Pat Walters, Tim Howard, and Lynn Levy.]

[JOHN WALTER: With help from Jessica Gross and Douglas Smith.]

[LAUREN SILBURT: Special thanks to Eric Asani, Sam Rudman, Abby Wendell ...]

[MARCUS DU SAUTOY: Sean Carrol, Annie Pack, Joe Gall ...]

[MARCELO GLEISER: And Natasha Gostwick of Storynory.com Okay, hope I passed. Bye.]

[ANSWERING MACHINE: End of mailbox.]

 

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