[RADIOLAB INTRO]

JORDAN: Hello, hello, hello?

JAD ABUMRAD: How do I want to introduce this tape to you? Have you heard this tape, Krulwich?

ROBERT KRULWICH: I have not.

JAD: This is actually the first—it's one of my first radio pieces.

JORDAN: You're not gonna be able to hear what we're saying as we're in freefall.

JAD: And I had two friends who were in love.

WOMAN: I want to take a picture of the two of you suited up with your helmets on.

JAD: Have since fallen out of love and fallen in love with other people. But at the time, they were very much in love, and they had decided they were gonna go skydiving.

ROBERT: Together?

JAD: Together.

INSTRUCTOR: Everything looks good. You ready for this?

JORDAN: Yes, I guess so.

INSTRUCTOR: Let's go skydiving!

JAD: So this is my friend, Jordan. He is getting into a plane.

INSTRUCTOR: All right. So let's check your harness.

JAD: He's got a MiniDisc recorder strapped to his chest. And I should just say that the piece ended up being really dumb, but it contains the best moment of tape I think I've ever recorded.

ROBERT: Okay.

JAD: And you're gonna hear it coming up. Okay, so as Jordan gets up into the sky ...

JORDAN: I just hope I don't mess myself.

JAD: They're like 7,000, 8,000 feet. I don't remember the number, but they open the door ...

INSTRUCTOR: Okay, are you ready to skydive?

JORDAN: Oh, [bleep]

JAD: He steps just to the edge, and he's about to go—you'll hear, there's going to be a moment.

Just listen.

ROBERT: Okay.

JAD: Okay, he is out of the plane now, he's hurtling through space, free-falling.

JORDAN: Whoo!

JAD: Within, like, a few seconds, he's at 100 miles an hour. Up to 150. 175 miles an hour.

JORDAN: Whoo!

JAD: Maybe 200, I don't know. And ...

JORDAN: Whoo!

JAD: ... there.

INSTRUCTOR: How did you like that?

JORDAN: [laughs] It was incredible! Oh my God!

JAD: That's the moment where the parachute opens.

JORDAN: I can not believe it!

JAD: And he is floating.

JORDAN: God, that's amazing.

ROBERT: Well, what happened to the girl?

JAD: I don't know.

ROBERT: You don't know?

JAD: Well, her MiniDisc recorder malfunctioned on the way down.

ROBERT: Oh.

JAD: But let's just rewind that back for a second.

JORDAN: Whoa, damn!

JAD: That transition right there from falling body to floating body?

ROBERT: Yeah.

JAD: I love that because at first he sounds like this dinosaur falling through the air, but then the sound changes and it's just like, "Whoa!" I don't know, it's like this moment of somebody falling out of control.

ROBERT: And then falling back in.

JAD: Yeah. It seemed like a good way to open the show, because this is gonna be a show where we take this idea of falling ...

ROBERT: And we walk it in all kinds of different directions.

JAD: Like ...

NEIL DEGRASSE TYSON: A point comes where you snap.

ROBERT: That's one.

SARITA: I loved him so much.

JAD: That's one.

JOAN MURRAY: It's very dark. It's very hellish.

ROBERT: And that's one.

FREDERICK COOLIDGE: I was netting 81.

JAD: There are 14,932 ways to fall on the radio. In this hour, we'll bring you eight. I'm Jad Abumrad.

ROBERT: I'm Robert Krulwich.

JAD: This is Radiolab.

ROBERT: And we are falling.

JAD: Number one ...

ROBERT: This one—this one is about—I don't know, would you call it terror, or just ...

JAD: No, it's about time, really.

ROBERT: Time. Okay, so we'll just call this one "Falling Time."

DAVID EAGLEMAN: Howdy.

ROBERT: This is David Eagleman.

DAVID EAGLEMAN: This is David here.

ROBERT: He's a neuroscientist, but back when he was a kid ...

JAD: How old were you? Just sort of ...

DAVID EAGLEMAN: I was—I was eight years old.

JAD: He had an experience which he says changed his life.

DAVID EAGLEMAN: Yeah.

JAD: He was playing in his subdivision in Houston, and there was a house nearby ...

DAVID EAGLEMAN: That was under construction. And my father told me not to go climbing around on the house under construction, but I was a boy, so I did. And I was looking at the edge of the roof, and I stepped on it, but in fact it was tarp paper hanging over the edge, and I—and I fell.

ROBERT: Oh, so you stepped onto the air, in effect. You just went, whoosh!

DAVID EAGLEMAN: Exactly. And what happened was the event seemed to take a very long time. I thought about whether I had time to grab for the edge of the roof, and I realized it was too late for that. So then I was looking down at the ground as the red-brick floor was coming towards me, and I was thinking about Alice in Wonderland, how this must be what it was like for her when she fell down the rabbit hole.

ROBERT: How long, by the way, was it from the top of the roof to the ground below?

DAVID EAGLEMAN: 0.86 seconds.

JAD: [laughs]

ROBERT: [laughs]

DAVID EAGLEMAN: That's how long it takes to fall 12 feet. I calculated that later.

ROBERT: [laughs] I see.

JAD: That would be one one thousandth ...

DAVID EAGLEMAN: Yeah.

JAD: And this whole experience left David Eagleman with a question that he could not get out of his mind.

DAVID EAGLEMAN: What happens to people when they're in a life-or-death situation and they have these thoughts that seem to take a long time? So at some point, I realized I needed to study this.

JAD: How would—how would you even study that?

DAVID EAGLEMAN: Well, the first thing I did, I took my entire laboratory to AstroWorld, which is the amusement park here in Houston.

JAD: [laughs]

DAVID EAGLEMAN: And we went on all of the scariest roller coasters. We brought all of our equipment and our stopwatches and had a great time. But it turns out, nothing there was scary enough to actually induce this fear for your life that appears to be required for the slow-motion effect.

JAD: [laughs]

DAVID EAGLEMAN: So, I searched around, and I finally found something called SCAD diving.

JAD: SCAD diving.

DAVID EAGLEMAN: It stands for "Suspended Catch Air Device."

JAD: Where do you do that?

DAVID EAGLEMAN: Turns out it's illegal in Houston, but I found one in Dallas. [laughs]

ROBERT: [laughs]

JAD: [laughs]

DAVID EAGLEMAN: So we made a road trip up to Dallas.

INSTRUCTOR: All right, jump number one.

JAD: And we actually found a reporter in Dallas who agreed to give this a try.

INSTRUCTOR: Put the harness on, and then I'll put this on over the harness.

APRIL: No one's ever died on this thing, right?

INSTRUCTOR: No.

JAD: This is April.

APRIL: I feel like my heart's in my throat.

JAD: She's very brave.

DAVID EAGLEMAN: You ride up to the top of this tower in this very rickety little elevator type of thing.

APRIL: Okay, we're rising up in the elevator right now.

DAVID EAGLEMAN: 150-foot tall tower.

APRIL: Not too fast.

DAVID EAGLEMAN: Climbing up and up and up.

APRIL: It doesn't seem that far when you're down there. Up here, it seems really far.

DAVID EAGLEMAN: It's like a 15-story building.

INSTRUCTOR: Okay, we're halfway.

APRIL: Halfway. [laughs] This is just halfway, I'm already freaking out.

DAVID EAGLEMAN: And ...

APRIL: My hands are starting to shake.

DAVID EAGLEMAN: ... at the very top, you're suspended.

APRIL: Like this?

INSTRUCTOR: Yes.

APRIL: Okay.

DAVID EAGLEMAN: You're hooked up to a carabiner.

APRIL: Oh, God. Okay.

INSTRUCTOR: Sit all the way back. Lean back.

ROBERT: Okay, so I want you to imagine this: you're up in the sky, you are facing the clouds, not the ground, you're attached to something which is about to be severed, and you will fall totally free into the void, unable to see what's about to happen to you, presuming a net—maybe.

APRIL: Oh, God. Okay. Don't let me die.

JAD: Three, two ...

APRIL: Really nervous right now.

JAD: And ...

APRIL: [screams]

JAD: Okay, wait, wait, wait, wait. One thing I forgot to mention: April actually wasn't part of David's study, but if she had been, she would have been wearing around her wrist this little device.

DAVID EAGLEMAN: A new device called the perceptual chronometer.

JAD: It's about the size of a watch, and it flashes numbers super fast. Way too fast to see normally. But the thought is if April falls and everything starts to slow down, well then these numbers should slow too, so that if she looks at her wrist as she's falling, she should be able ...

DAVID EAGLEMAN: To now read the watch. That would be impossible under normal circumstances.

JAD: Back to April.

APRIL: Really nervous right now.

JAD: Three, two, and ...

APRIL: [screams] Oh my God! Oh my God! Oh my God, this is the scariest moment in my life! [laughs] Oh my God!

DAVID EAGLEMAN: I should probably tell you guys the results of this study, but ...

JAD: Yeah, yeah, yeah. So do people report that time slowed down enough for them to read the number?

APRIL: I'm alive.

DAVID EAGLEMAN: No.

ROBERT: No?

DAVID EAGLEMAN: Turns out when you're falling you don't actually see in slow-motion.

JAD: Aww.

DAVID EAGLEMAN: Yeah, it's not equivalent to the way a slow-motion camera would work. Even though people feel like it's going in slow-motion, it's something more interesting than that.

JAD: Because here's the thing: right after people did the jump, he would ask them ...

DAVID EAGLEMAN: How long they thought their fall took.

JAD: The right answer, if they'd had a stopwatch ...

DAVID EAGLEMAN: Just under three seconds.

JAD: But what people would say ...

APRIL: How long—when you were falling, how long did it ...

WOMAN: 10 seconds.

WOMAN: It felt—it felt like time was stopped.

JAD: So how do you explain that? Like, time's not slowing in the moment, but seems to be slowing after the moment?

DAVID EAGLEMAN: Well, I came to understand that it's a trick of memory. Normally, our memories are like sieves. We're—we're not writing down most of what's passing through our system.

JAD: But he thinks that when you go ...

APRIL: [screams]

JAD: ... you know, life or death moment ...

APRIL: Oh my God!

JAD: ... in that instant, our memories go wide open.

DAVID EAGLEMAN: Because that's what memory is for. It's for when everything hits the fan, you want to write it down and remember it.

JAD: So all of it goes right to your hard drive. The clouds, the feeling of the air, "Oh, look there's a guy in a blue shirt."

DAVID EAGLEMAN: So, when you read that back out, the experience feels like it must have taken a very long time. It must have.

ROBERT: Normally, the trivial stuff gets dumped, but in this situation, it gets written.

JAD: Then you realize how much trivial stuff is in there.

DAVID EAGLEMAN: So for example, I just recently interviewed a gentleman who had been in a motorcycle accident, and as his helmet was bouncing along off the asphalt, he was composing a little song to the rhythm of his helmet bouncing.

JAD: [laughs]

ROBERT: Was he in his helmet or had the helmet flown off?

DAVID EAGLEMAN: Yes, he was in his helmet. That's ...

JAD: Was he—before I guffaw too loudly, was he okay as a result of this bouncing?

DAVID EAGLEMAN: Yes, he was okay.

JAD: Wow, that's amazing! So his head was going thump, thump, thump, and he's like, "Hey, that's a good rhythm."

[ARCHIVE CLIP, Alice in Wonderland: Oh my, what a peculiar place to have a party!]

[ARCHIVE CLIP, Alice in Wonderland: Goodness, what if I should fall right through the center of Earth?]

JAD: Number two, falling in love from producer Lulu Miller. So set this up for us.

LULU MILLER: Well, this is a love story. And in some ways, it's a very typical love story. And in other ways, it's ...

JAD: Just not.

LULU: Yeah. The girl is a really good friend of mine. We're gonna call her Sarita. And the boy we'll call Simon.

LULU: When was the first time that you ever saw Simon?

SARITA: I don't remember the exact moment, but I do remember sitting in the lunchroom with the girls at the table and sort of scoping out the boys. And he was definitely the skinniest.

LULU: [laughs]

SARITA: He just looked like a really nice guy. Olive-skinned, thick hair, and he made really good eye contact to the point where it's a little flirty. There's no break in the eye contact. It's like constant to the point where I think it could be uncomfortable for some people, but I just really—I really liked it.

LULU: When was the first time you talked to him?

SARITA: Well, we had a class together our freshman year. We talked a lot in class, and after class, on the paths around campus.

LULU: And that's how it went all freshman year.

SARITA: Sophomore year.

LULU: Junior year.

SARITA: Mm-hmm.

LULU: They were sort of like particles that just kept colliding.

SARITA: In the lobby of the dorm, on the sidewalk.

LULU: And each time it was new.

SARITA: A new topic or a new idea.

LULU: For instance, one of them would walk by carrying a book ...

SARITA: Poisonwood Bible.

LULU: And the other one would say, "Oh, I love that book."

SARITA: Yeah.

LULU: They just clicked.

SARITA: And again, the eye contact. We would talk and be connected with the eyes. That's what I really was falling for about him, there was like an attentiveness beyond.

LULU: I want to ask you one thing which—like, you just said, "I'm falling for him."

SARITA: Mm-hmm?

LULU: Is that the way it felt? I mean, people always say "Falling in love." Did it feel like falling?

SARITA: Yeah, it does because it feels out of control. And there's a moment where it feels like I let go and allowed myself to feel it totally.

LULU: Though there were some moments where she wondered if she should.

SARITA: Yeah.

LULU: Like sometimes she'd walk by Simon on the path, look up and smile ...

SARITA: And he'd snub me.

LULU: But then ...

SARITA: We'd run into each other, and we'd talk ...

LULU: She'd let herself start falling again.

SARITA: This is really fun in this moment. And I realized years later that every time we ran into each other, he has no idea that those were me. [laughs]

LULU: Really?

SARITA: Yeah.

LULU: Hi.

SIMON: Hello?

LULU: Could you hear me vaguely? [laughs]

SIMON: Yeah.

LULU: Can we start out talking about your condition?

SIMON: Yeah.

LULU: What's it called?

SIMON: Prosopagnosia.

LULU: Prosopagnosia.

SIMON: Yes.

LULU: Sounds like a delicious fruit salad.

SIMON: It could be a cocktail.

LULU: And what is that—what is that word?

SIMON: Let's see. Well, "agnosia" is a lack or an inability, and "proso" is the Greek for face.

LULU: Oh.

SIMON: Face blindness.

LULU: This, of course, is Simon.

SIMON: There's a little piece in my brain that's missing and I have a really, really hard time recognizing faces, remembering faces.

LULU: And how does it work? Is it just that you forget where you know people from?

SIMON: No. If I've passed you in the street, I can't swear that I've ever seen you before.

SARITA: So he didn't know. He couldn't string those together as all the same person having the same conversation.

SIMON: Right, no way.

LULU: Even their first kiss. He didn't realize he was kissing a girl he'd actually known for years.

SIMON: [laughs] Yes.

SARITA: Yeah.

LULU: So were you, like, totally shocked?

SARITA: I was totally blown away.

LULU: Who was that person to you?

SIMON: I knew it was the cheese-plate girl.

LULU: [laughs] Yeah?

SIMON: I did not know it was field-house girl.

LULU: So what did you say?

SARITA: I think I just asked a lot of questions.

SIMON: You know, she was interested.

SARITA: Like, "Oh ..."

SIMON: "How does this work?"

SARITA: Yeah.

SIMON: So I probably said, "If you went to the park and started looking at trees, their shapes are different, their sizes are different, but to try to remember a thousand or two thousand of those ..."

SARITA: How do you pick it out?

SIMON: It's just hard. It's just computationally difficult.

SARITA: Yeah.

LULU: What details did you know about her?

SIMON: I knew it was good to be with her. The experience of being with her, I think ran ahead of my sense of her biography. So it was a leap.

LULU: It was a leap.

SIMON: Yeah. Let's try this.

LULU: So they embark on this relationship, which, you know, has its quirks.

SARITA: Right.

LULU: Like for instance, if they were meeting up somewhere public ...

SARITA: I'm gonna need to wave first.

LULU: Hmm.

SARITA: And backpacks.

LULU: She's always gotta wear the same one.

SIMON: Voice really helps.

SARITA: But I would get a little bit anxious when we'd have to meet each other somewhere.

LULU: Yeah.

SARITA: Because I knew if another curly-haired girl walked there before I did ...

SIMON: I'm thinking, "Is that her?"

SARITA: He would, like, smile and wave at her. [laughs]

SIMON: It's just awkward. It's just kind of embarrassing.

SARITA: Yeah.

LULU: And somewhere along the line, Sarita found out that that eye contact that drew her in, it wasn't really about her. It was something he did ...

SARITA: With everyone on the off-chance that they're his friend.

LULU: Wow.

SARITA: That's what I think the eye contact is.

LULU: Did that—did that make you step back at all?

SARITA: No. By then I had already fell.

LULU: And plus, Sarita at that time was getting really into Buddhism. And not just a little bit. She went and lived with Buddhist nuns for a year in Sri Lanka.

SARITA: And so the idea of impermanence and, you know, we think we have a self, but what really is a self? What it means to know someone? All of that was part of my world, and so this idea that he didn't recognize me didn't seem so—as important as the present moment.

SIMON: It just kept getting better.

LULU: And then what happened? You graduated, then did you move in together?

SARITA: Yeah.

LULU: Was it in Philly?

SARITA: It was in Philly, on Sansom Street.

LULU: A year and a half goes by, and then one day ...

SIMON: I woke up, and I swear to God, like, all the leaves fell off the trees. Fall turned into winter.

LULU: And Simon told Sarita it was over.

SARITA: Something about a core that I'm lacking.

LULU: He said you were lacking a core?

SARITA: Yeah.

LULU: What does that mean?

SARITA: I don't know. I'm not sure what it means.

SIMON: Good God, I knew the core would come up. The core, the core—what I was trying to talk about was lingering doubt, whether—whether this was it. Wondering could I fall further?

SARITA: He just wasn't sure that he loved me, and then at that point kind of backtracked and denied having ever really loved me. Yeah. That—that's how it was.

LULU: Did you feel like you at a certain point started to actually fall out of love with him? Like ...

SARITA: No. There was no falling. It was just like I was at the bottom of a well, sitting and stewing. I loved him.

LULU: Yeah.

SARITA: So much.

LULU: And would you see him in the neighborhood? Because you're still neighbors, right?

SARITA: Yeah. We would see each other around at parties. And he was working at a restaurant that had an outdoor patio, and I walked by there a few times without him knowing it was me, where I could see him and look at him.

LULU: But you got to just be hidden.

SARITA: Yeah. I got to just walk by.

LULU: Yeah.

SARITA: So there is comfort in that.

SIMON: I didn't know that. I didn't know that. Yeah, it's hard somehow that I wouldn't see her. It's like she'd faded back into the crowd quickly.

SARITA: I had become lost.

SIMON: It's actually haunting to me, you know, to hear that.

ROBERT: And we'll be right back.

[LULU: Oh, that message is still there. Hi, it's Lulu calling with the credits. Radiolab is supported in part by the National Science Foundation, and the Alfred P. Sloan Foundation, enhancing public understanding of science and technology in the modern world. More information about Sloan at www.sloan.org. Radiolab is produced by WNYC. Good-bye.]

[ANSWERING MACHINE: End of message.]

[JAD: Science reporting on Radiolab is supported in part by Science Sandbox, a Simons Foundation initiative dedicated to engaging everyone with the process of science.]

JAD ABUMRAD: Hey, I'm Jad Abumrad.

ROBERT: I'm Robert Krulwich.

JAD: This is Radiolab, and today—today, we're falling in many different flavors, and we're at number three.

ROBERT: So next, we have the story of a different kind of fall.

DAVID QUAMMEN: All right.

ROBERT: Or faller.

DAVID QUAMMEN: Yeah.

JAD: Comes from science writer, David Quammen.

ROBERT: One article in particular that he wrote caught our attention.

ROBERT: All right, I'm gonna quote you to yourself.

DAVID QUAMMEN: Okay.

ROBERT: "Nowadays, true enough, we know quite a bit about cats, they've been dissected in uncountable numbers. Their anatomy, their physiology, their behavior have been minutely studied, but there's much that we still don't know. Among all the other intractable issues, one in particular interests me, and that is: what's the terminal velocity of a plummeting cat?"

JAD: [laughs] Why—can you give me a little history, why did that question interest you?

DAVID QUAMMEN: I mean, when I used to write for Outside Magazine, I would browse through journals, and I would come across obscure papers. How I happened upon the Journal of the American Veterinary Medical Association, familiarly known as JVAMA ...

JAD: [laughs]

ROBERT: [laughs]

DAVID QUAMMEN: ... I don't know. I don't remember. But I'm sure that that was the starting point.

ROBERT: Because it was in that journal that David ran across a research paper ...

DAVID QUAMMEN: Yeah.

ROBERT: ... by two vets ...

DAVID QUAMMEN: Wayne Whitney and Cheryl Mehlhaff.

ROBERT: ... who worked in ...

DAVID QUAMMEN: The Midtown Veterinary Hospital.

ROBERT: And they noticed that in Manhattan ...

DAVID QUAMMEN: There were a lot of cats falling out of windows, high windows, falling off ledges, falling off roofs.

JAD: What—what is a lot? I mean, how many cats were coming into this place?

ANN HOHENHAUS: We saw 132 cats fall in a five-month summer period.

JAD: 132 cats.

ROBERT: That's Ann Hohenhaus. She actually works in the veterinary hospital.

ANN HOHENHAUS: Right here at the Animal Medical Center.

ROBERT: And she's been there since that research paper was written back in 1986.

ANN HOHENHAUS: When I came to New York City, I said, "What do you mean cats fall out of buildings? It doesn't make sense." I said, "Why would the cat fall out?"

ROBERT: But we'll get back to her in just a little bit.

DAVID QUAMMEN: 132 in five months, that's almost a rain of cats.

ROBERT: Well, no, don't say that, because I think people should visit New York without cat-receiving umbrellas.

JAD: Five, eight, two ...

ROBERT: What are you doing?

JAD: I'm doing math to see how many that is in a week of ...

ROBERT: [laughs]

DAVID QUAMMEN: 35 days, it's about …

JAD: Jeez, that's about a cat a day!

ROBERT: Well, it's a shame we can all agree about that.

JAD: But, according to David, it's actually not as much of a shame as you would think.

DAVID QUAMMEN: 22 of the cats that they saw had fallen from eight stories or higher, and out of those 22, only one died. 21 cats survived from eight stories or higher.

JAD: Wow, that's a long way!

DAVID QUAMMEN: And there was one cat that fell 32 stories, and the cat had a little bit of sort of thoracic bruising and a chipped tooth, and that was it.

JAD: So—I mean, how in the world do cats—I mean, we all know cats land on their feet, yeah, yeah, yeah, but how do they do that? Like, these are not magical creatures.

ROBERT: Well, if you go back about 1,000 years ...

DAVID QUAMMEN: You know, it was thought that they consorted with witches, with the devil, and their reputation got darker and darker. The more people started to distrust and dislike cats, the more they started to do horrible things to them. They would put cats in a barrel, and then they would run the barrel through with swords.

JAD: Oh!

DAVID QUAMMEN: Also, throwing them out of windows, the defenestration of cats.

JAD: What does "defenestration" mean?

ROBERT: Throwing out the window. Fenestra is the window.

JAD: Really? There's a word for that?

DAVID QUAMMEN: Oh Jad, add that to your active vocabulary today.

JAD: I plan to. So what would happen when they would defenestrate these cats?

DAVID QUAMMEN: The cats would land on their feet and walk away, and that made people even crazier!

ROBERT: [laughs]

JAD: Now of course, we love our cats now. We don't do that to our cats anymore.

ROBERT: But when we went to visit Ann back at the veterinary hospital, we were asking her about the falling cats research paper, which was called The Feline High-Rise ...

JAD: The Feline High-Rise Syndrome.

ROBERT: Then, the mystery of how cats can fall from these amazing heights and survive, got a lot deeper.

JAD: Yeah.

ANN HOHENHAUS: Well, cats that fell less than five stories ...

ROBERT: They did fine, she said.

ANN HOHENHAUS: ... not too bad. Cats that fell over nine stories ...

ROBERT: They did fine too, she said.

ANN HOHENHAUS: ... not so bad.

JAD: Which is weird.

ROBERT: But ...

ANN HOHENHAUS: Cats that fell between five and nine ...

ROBERT: Between five floors and nine floors ...

ANN HOHENHAUS: ... had really serious injuries, and had more injuries per cat.

JAD: So cats that fell a little ways were okay and cats that fell a long ways were okay, weirdly, but this five to nine thing?

ROBERT: Yeah, how do you account for that?

JAD: Yeah, what is that? What's going on?

ANN HOHENHAUS: So we had to get a physicist to help us explain this.

ROBERT: This is where we get back to what Quammen called ...

DAVID QUAMMEN: The terminal velocity issue.

JAD: Or here's how Ann put it to us ...

ANN HOHENHAUS: Well ...

ROBERT: Say you're living on the 30th floor of a building, and it's summertime.

ANN HOHENHAUS: You get done at work at 5:00, you go home, get there about 6:00. The apartment's hot and stuffy, and you open up those windows, and Fluffy says, "Hmm, I'd like that pigeon out there." And the next thing you know, it's a misstep, and ...

[cat meows]

ANN HOHENHAUS: ... as the cat starts to fall, he's all disoriented.

JAD: And almost immediately ...

DAVID QUAMMEN: Probably within the first six feet ...

ANN HOHENHAUS: The cat's brain says, "Okay, turn your front half over. Now bring your back legs around."

ROBERT: That's like instinct.

DAVID QUAMMEN: A cat can apparently do that move lickety-split.

ROBERT: But the cat is still speeding up.

ANN HOHENHAUS: Going faster and faster.

JAD: Three floors, five floors, seven floors.

ROBERT: And after falling about nine floors ...

JAD: And accelerating to speeds ...

DAVID QUAMMEN: Up to about 60 miles an hour ...

JAD: ... something happens.

DAVID QUAMMEN: You hit an equilibrium between the pull of gravity and wind resistance.

JAD: What he means is gravity is pulling down on you, and the peak pull is between five and nine floors for a cat, but after nine floors, the wind resistance, which all the while has been pushing back up on you, starts to slow you down.

DAVID QUAMMEN: You don't speed up anymore.

ROBERT: So that's your cruising speed.

DAVID QUAMMEN: That's your cruising speed. After the cats hit terminal velocity and the sensation of acceleration was gone, they relax. They sort of stretch out like a flying squirrel, and then they hit the ground, belly flop ...

ROBERT: [laughs]

JAD: And you're saying that because they hit this cruising speed and then relaxed into the flying squirrel the impact is less?

DAVID QUAMMEN: Yes.

ANN HOHENHAUS: Yeah. And our record here—it wasn't in this paper, but our record is 42 floors and the cat walked away.

JAD: Wow!

ROBERT: 42 floors! Is that a lucky cat, or is that just plain physics? Should cats everywhere go to the 42nd floor before jumping out of the window?

ANN HOHENHAUS: No cat should ever jump out of a window. [laughs]

JAD: That's right, stay indoors. [cat meows] No, Fluffy! Back! Okay, so the next falling, what are we going to call these falling ...

ROBERT: Falling episodes?

JAD: No, is there an F-word we could use?

ROBERT: Features?

JAD: Yes, great. Great!

ROBERT: Our next falling feature ...

BRIAN GREENE: Oh, boy!

ROBERT: ... we invited Columbia University physics professor Brian Greene into our studio.

BRIAN GREENE: Do I get to play with any buttons?

JAD: Uh. yeah.

ROBERT: We wanted to ask him well, really one of the most basic questions you could ask a physicist ...

JAD: Why do we fall?

BRIAN GREENE: You know, we all know that Newton wrote down a law of gravity to calculate how gravity acts from one object to another.

JAD: You know, if you drop your pen ...

BRIAN GREENE: That's right. But there's a difference between being able to predict what will happen and be able to explain why it happens. And Newton could not explain why it happens. He could only tell you what would happen.

JAD: But I mean, how it works is it just pulls the pen down.

BRIAN GREENE: What does that mean, though? How does it pull it? I don't see anything between the table and your pen, so what is the agent responsible for the pull?

JAD: Um—hmm.

ROBERT: This is something even Albert Einstein himself couldn't quite figure out.

BRIAN GREENE: He was struggling to understand how the force of gravity works. And it was a big, big puzzle.

ROBERT: And the legend goes that Albert Einstein was walking around one day, and he found himself imagining a person riding in an elevator. And all of a sudden, the cable gets cut and the elevator starts to plunge right down towards the Earth.

JAD: The version I know is that he was actually sitting at his desk looking out the window, and was imagining window washers falling sort of from their scaffolding, but it's the same—same exact idea.

ROBERT: [laughs] Anyway, we're gonna stick with the elevator version for now. Einstein imagined this person standing actually on a bathroom scale ...

JAD: In the elevator.

ROBERT: ... in the elevator. This is before the cable gets cut.

BRIAN GREENE: If the person is in the elevator standing on a scale, they see that they weigh 160 pounds.

ROBERT: And then—snip!

BRIAN GREENE: When the elevator cable is cut, they look down at the scale and the scale will drop to zero, because the scale will be falling away from their feet at exactly the same rate that their feet are falling. So their feet won't push on the scale any longer because the scale will be moving downward with them.

JAD: In my mind, I imagine like a Hollywood movie where it's falling so fast, everybody kind of drifts up almost.

BRIAN GREENE: That's right. So Einstein said to himself, "Hang on a second, here's an environment where, in essence, I can turn gravity off."

ROBERT: Hmm.

BRIAN GREENE: Another way of saying it that flips it around and may make it more clear, just as you can turn gravity off by snapping the cable, you can actually simulate gravity by pulling on the cable that pulls that elevator up really, really quickly, because now the scale is running into your feet. If you're standing on that scale, it won't read 160, it might read 250.

JAD: Huh. It seems like gravity and being pulled up really fast, they're the same thing.

BRIAN GREENE: They are.

ROBERT: Jad, look at you! You just had the insight on your own!

BRIAN GREENE: That's right!

JAD: He walked us 17 steps, and I just made the last baby step.

BRIAN GREENE: Well, now you did it. You did it, man. So whenever you're faced with a gravitational problem, this allowed you to ignore gravity and translate it into a problem about motion.

JAD: But does that solve the 'what is gravity' question? It just sort of ...

BRIAN GREENE: No, he then had to make one more leap, and it's not obvious how he took the final step, but the final step was to realize that the 'what is gravity' is the curvature of space and time. That's a leap.

JAD: I don't know what that means.

ROBERT: Well, this is a very difficult concept ...

JAD: Do you understand it?

ROBERT: I understand what Einstein tells you when he explained it. He said if you imagine the universe as a vast rubber mat, a rubber mat held really, really taut.

JAD: Yeah?

ROBERT: Let's just take—oh, I don't know, let's take the Earth and just plop it onto the mat. So what just happened?

JAD: Well, it sunk into the rubber.

ROBERT: It stretched the rubber, didn't it?

JAD: Yeah, I mean ...

ROBERT: So the rubber is kind of curved around underneath it.

JAD: Yeah.

ROBERT: In Einstein's mind he thought, "Maybe this is how to explain gravity. This is what gravity is."

BRIAN GREENE: That curved shape of space, he said.

JAD: Hmm.

BRIAN GREENE: And the pen falls because it's following a contour in that curved space-time environment.

JAD: Oh, so if we're living on the curve, then we're constantly falling. We're falling down that contour.

ROBERT: We're moving down that curve, yeah. We have no choice.

BRIAN GREENE: And the reason why right now I feel the chair pushing up on me is again, my body also wants to slide down, but the chair's getting in the way.

JAD: So we're all sort of on some kind of slope sliding down, unless we're ...

BRIAN GREENE: Yes, that's right. That's right.

JAD: I like that.

BRIAN GREENE: Yeah.

JAD: I'm now an adherent to that theory.

BRIAN GREENE: There you go.

JAD: Not knowing anything else. Now for number five, should we call it "Falling Fortunes?" Or ...

ROBERT: Well, "Falling Fortunes" is a good one for this, I think.

JAD: Yeah.

ROBERT: Because someone is seeking fame and fortune, and then ...

JAD: Falls.

GARRETT SODEN: The idea of the gravity hero, to me, one of the things that—it goes along with ...

JAD: Was that a term that was used, gravity heroes?

GARRETT SODEN: No, that's my term.

JAD: I like it, though. It's a really catchy term.

GARRETT SODEN: Well, thanks. Yeah.

JAD: This is Garrett Soden, he's an author.

GARRETT SODEN: Author of Defying Gravity.

JAD: Original title.

GARRETT SODEN: Falling: How Our Greatest Fear Became Our Greatest Thrill - A History.

JAD: And speaking of history and fears and thrills, and I would add to that list, tragedy, he tells the following story ...

GARRETT SODEN: It really started with Niagara Falls, because up to that point, people had done all kinds of things at Niagara Falls.

JAD: To back up, it is the 1850s, and at Niagara Falls, you've got these two guys doing tightrope tricks over the falls.

GARRETT SODEN: Yeah.

JAD: A fellow named Charles Blondin ...

GARRETT SODEN: Famous French wire-walker.

JAD: ... and a Canadian guy who called himself ...

GARRETT SODEN: The Great Farini.

JAD: And they would duke it out.

GARRETT SODEN: Right. Blondin came out, strung a rope across Niagara Falls, put a chair down balanced on two legs, and stood on it.

JAD: Whoa!

GARRETT SODEN: One time, he carried a guy over.

JAD: Oh, wow.

GARRETT SODEN: He had to keep upping the ante, so ...

JAD: So for his greatest trick ...

GARRETT SODEN: He carried a small cast iron stove on his back with some firewood. He got out there and he put the stove down, lit a fire, had a couple of eggs and a frying pan, and made an omelet.

JAD: [laughs] Right over this churning, like, rapid?

GARRETT SODEN: Yes.

JAD: Wow!

GARRETT SODEN: So The Great Farini came out with a washing machine, that was his answer to Blondin. Washed some clothes out there. Yeah.

JAD: But the thing to know about these guys is this was—this was basically just a show, because for example, the wire that they walked on was pretty wide.

GARRETT SODEN: About the diameter of a coffee cup.

JAD: And really, they were just avoiding the big trick.

GARRETT SODEN: The most anticipated trick ...

JAD: The one that everybody was waiting for.

GARRETT SODEN: ... was somebody going over the falls in a barrel.

JAD: The guy who did that would be the real gravity hero, you wire-walking wusses. Niagara Falls is one of the great forces of nature. Every second, 600,000 gallons fall over the edge, pound the rocks below with such a fury that you can hear it five miles away. Which is why in 1850 when P.T. Barnum saw the Falls ...

JOAN MURRAY: He said that if someone could figure out a way to go over that, that would be a huge stunt that would give them fame and fortune.

JAD: That's Joan Murray, she's ...

JOAN MURRAY: I'm a poet.

JAD: ... she's a poet. She's written a whole book ...

JOAN MURRAY: In verse.

JAD: ... about the first person to conquer the falls.

JOAN MURRAY: In a barrel.

JAD: And it's called ...

JOAN MURRAY: Queen of the Mist.

ROBERT: Queen of the Mist, huh. So it wasn't a guy then.

JAD: No, I just said it was a guy to set you up so that you would ask me that question, because in fact, it was a woman.

ROBERT: Wow! Props to her!

JAD: Thank you for acting surprised.

ROBERT: What's her name, Jad?

JOAN MURRAY: Annie Taylor.

JAD: When we first meet Annie Taylor ...

JOAN MURRAY: This was 1901.

JAD: ... she was ...

JOAN MURRAY: Down on her luck.

GARRETT SODEN: She'd been a—she'd done a lot of different things. She'd run a dancing school, she had been a principal, she had traveled all over the world.

JAD: Her only child had died, her husband right after that. And she was broke. But then it hit her. She was sitting at home.

GARRETT SODEN: Sitting in her apartment ...

JAD: In Bay City, Michigan.

GARRETT SODEN: And for some odd reason, she read an article about the goings-on at Niagara Falls, and she decided she would go over Niagara Falls in a barrel.

JOAN MURRAY: Yeah.

JAD: Why? I mean, do we know?

JOAN MURRAY: She's looking to save herself from the poorhouse.

GARRETT SODEN: She was after money.

JAD: And when she read about these guys at Niagara Falls, she thought, "This is it."

GARRETT SODEN: Right. So she called a cooper to build the barrel. At first, he refused to build it when he heard what her plan was, but finally he did.

JAD: And not long after, Annie was on a train with her barrel headed to the falls.

JAD: By the way, what day are we talking about? Just so we have a date.

JOAN MURRAY: On October 24 in 1901.

JAD: Okay.

GARRETT SODEN: Word had spread.

JAD: This was gonna be a spectacle.

JOAN MURRAY: Everyone was there.

GARRETT SODEN: Mobs of people.

JAD: Thousands.

GARRETT SODEN: Up and down the river.

JAD: Tens of thousands. And Annie shows up ...

JOAN MURRAY: Waving to the crowd.

JAD: ... wearing a very fancy Victorian dress.

JOAN MURRAY: And a hat with ostrich feathers.

JAD: Wow!

JOAN MURRAY: She's quite the lady, but then they go on an island where she changes ...

JAD: Into some gym clothes.

JOAN MURRAY: And now she gets in the barrel.

JAD: They tow her out to the middle of the river ...

JOAN MURRAY: And then they knock and cut the rope, and off she goes to the brink.

GARRETT SODEN: The roar of the river ...

JOAN MURRAY: "Enormous. And it's wet at my feet, and I'm feeling while I'm in there that this is miserable."

JAD: The interesting thing is that in Joan's poem, she actually becomes Annie.

JOAN MURRAY: "I careened and spun."

JAD: She's in the barrel getting hurled down the river, tossed and turned.

JOAN MURRAY: "My brain torn ..."

JAD: And as she gets closer to the edge—it's about a half-mile journey—she begins to hallucinate.

JOAN MURRAY: "And I glimpse through the turbulence, there was my young husband. In his arms, our baby trembling and whimpering as ..."

JAD: And then ...

GARRETT SODEN: This moment of weightlessness.

JOAN MURRAY: She's going ...

JAD: Down into the pools below.

GARRETT SODEN: The great mass of foam, and boiling water.

JAD: And then she shoots out again.

GARRETT SODEN: Through the buoyancy of the barrel, about 15 feet in the air.

JAD: Wow!

JAD: The barrel crashes back.

GARRETT SODEN: Back down on the water.

JAD: And then it floats over to some rocks, and a rescue team paddle out to the barrel right away.

GARRETT SODEN: They get the barrel, and they have to saw it open.

JAD: The crowd no doubt is thinking, "That woman is dead. There's nothing but a dead woman in that barrel."

JOAN MURRAY: But ...

JAD: When they pull her out ...

GARRETT SODEN: Pull her out ...

JOAN MURRAY: She's alive. "I am alive." She took on this thing that the world was waiting for and she did it. She was the first to ever try.

JAD: And Joan, when she was pulled out of that barrel, and presumably she's gonna take the next step into fame and fortune, what happened?

JOAN MURRAY: More or less nothing. She stepped out of the barrel, and she didn't look right. She didn't look like a hero.

ROBERT: What does that mean?

JAD: Well, I've kept something from you, Krulwich.

ROBERT: What?

JAD: The thing I haven't told you is that, not only was she wet and soggy, and according to newspaper accounts, hysterical—I mean, who wouldn't be? She was 63.

JOAN MURRAY: She was your grandmother.

JAD: She was an older lady. Like Joan said, you know, for the hero-consuming public, she just didn't look right.

GARRETT SODEN: After that exhibition, her manager ran off with the barrel. And he took the barrel, and he started going on the circuit with a lovely young woman that he claimed was Annie Taylor.

JAD: No!

GARRETT SODEN: Much better showpiece.

ROBERT: Ay-yi-yi. What happened to Annie, though?

JOAN MURRAY: She would drag herself to Niagara each spring and summer.

GARRETT SODEN: She would just sit on the street with a barrel. It wasn't the original barrel, but it was a barrel.

JAD: And do what?

GARRETT SODEN: She probably had photographs of herself that she signed.

JAD: And did she ever make any money off this?

JOAN MURRAY: No. No, she died in a poorhouse.

GARRETT SODEN: Which is where she didn't want to wind up, but that is where she wound up.

JAD: And just 10 years later, somebody repeats Annie's feat.

JOAN MURRAY: A man. And he tours the world.

JAD: Bastard!

JOAN MURRAY: Yeah, bastard!

JAD: But ...

JOAN MURRAY: Because the heavens are merciful ...

JAD: ... during this guy's victory lap, as he's traveling around the world ...

JOAN MURRAY: He slipped—he slipped on an orange rind in Australia or New Zealand, got a compound fracture of his leg.

JAD: Ha! [laughs]

JAD: She says that leg got gangrene and he died.

JOAN MURRAY: Yeah. There is—there is cosmic justice.

JAD: Are you asleep? Hey!

ROBERT: Hi.

JAD: Do you even know where you are right now?

ROBERT: Did you see what I did with my leg?

JAD: What?

ROBERT: I kicked myself awake. Did you see that?

JAD: I heard it. I'm Jad Abumrad.

ROBERT: Oh, I'm Robert Krulwich.

JAD: And our next falling feature is ...

ROBERT: Is falling asleep, but with a little kick.

JAD: This is Radiolab.

FREDERICK COOLIDGE: Let's do it.

JAD: Well, tell me your name first, and just tell me how you would like to be identified on air.

FREDERICK COOLIDGE: You can call me Fred. I like it the best.

JAD: Okay.

FREDERICK COOLIDGE: My full title is Professor Frederick L. Coolidge, University of Colorado at Colorado Springs.

JAD: So just so we get our definitions right, what is a hypnic jerk?

FREDERICK COOLIDGE: It appears to be this—what seems to be a reflex. Everybody's experienced it. It's you're still semi-conscious, then you start to feel kind of dreamy. You start to feel this loosening of your thoughts, loosening of your reality.

ROBERT: Hmm.

JAD: But just as you're about to go under, he says ...

FREDERICK COOLIDGE: Just at the first onset of sleep ...

JAD: Bam!

FREDERICK COOLIDGE: One big jerk.

JAD: And then you're ...

FREDERICK COOLIDGE: Awake.

JAD: Usually you wake up with this feeling of like, "Oh, my God! Oh, my God! Oh, my God! Oh, all right."

FREDERICK COOLIDGE: And, you know ...

JAD: Wait, how did you start studying this?

FREDERICK COOLIDGE: I was working at Kentucky Fried Chicken. Can I say that on the air?

JAD: Yeah, of course.

FREDERICK COOLIDGE: For a dollar an hour, and I just thought, "Man." I still can't eat coleslaw to this day, because I would do 100 pounds of coleslaw a day. So, I saw this ad on campus, and it said, "Somebody to work in a sleep lab." So I went and applied, and I ended up in the beginning cleaning toilets, but I just got into all of sleep. I thought it was fascinating. And I got fascinated by these giant jerks at the beginning of sleep, and I said, "What is that?" You know? And they said, "Oh, that's a hypnic jerk." I said, "What is that?" And they said, "That's a hypnic jerk."

JAD: [laughs]

JAD: In other words, no one could really explain to him why these things happen.

FREDERICK COOLIDGE: That's right.

JAD: So he started poking around, and there were some theories, you know, having to do with, like, physiological changes in your body.

FREDERICK COOLIDGE: You know, a lowering of oxygen content or something like this.

JAD: But that kind of explanation didn't really satisfy.

FREDERICK COOLIDGE: It really doesn't say well, why? What was its function? And as I started to look at the literature, I saw that we had a very long history sleeping in trees. If we go back to Australopithecus afarensis—this is Lucy—three million years ago. Lucy was bipedal. I mean, walking on two legs.

JAD: Lucy lived in the trees, but unlike the other primates, she would sometimes go down to the ground.

FREDERICK COOLIDGE: But on the ground, you've got big birds, you've got snakes, tigers and reptiles. That ground life was stressful, but at night she crawled up the tree for safety. She climbs up in that tree, drops food there for her baby, and she's going to drop off to sleep.

JAD: Her muscles loosen, her hands uncurl.

FREDERICK COOLIDGE: She starts to have that relaxation.

JAD: Pretty soon she can't feel the tree under her back or hear the noises down below.

ROBERT: Hmm.

JAD: Stay with me, Krulwich.

ROBERT: Okay.

JAD: She feels like she's floating—or falling.

FREDERICK COOLIDGE: Lucy! Falling! Falling!

JAD: That means ...

[animal growling]

FREDERICK COOLIDGE: It may be a real good idea to wake up from that. Sleep was such a dangerous proposition for so many millions of years that something like the hypnic jerk, if some of those primates had that behavior, they may have been just slightly more likely over millions of years to adapt and survive.

JAD: We haven't gotten rid of it yet is what he's saying.

ROBERT: So that's my trick is just basically so I don't get eaten by a lion all these many years ...?

JAD: Yeah, that's what he's saying. It's sort of like a Lucy echo.

ROBERT: Do we know this, or are we just imagining?

JAD: No, how are we gonna know this? This is just a story. But there's at least one tantalizing bit of evidence to support this idea.

FREDERICK COOLIDGE: You ask college students what are the most common dreams that you have, and falling is number one or number two most common theme. And if you go on a college campus, you know, thanks to OSHA, right? You have no chance of falling off anything. They'll make sure that your fullest drop is like a foot or six inches. Even then, it'd have big yellow and red signs all over it. But they dream of falling? What?

JAD: And by the way, the next most common dream after falling is being chased by an alien in a blue dress.

ROBERT: No it isn't.

JAD: Is too.

[ARCHIVE CLIP, woman: You're walking, and you don't always realize it, but you're always falling.]

DAVID EAGLEMAN: Well actually, I have a random one for you guys about falling. As I was driving over here I was thinking about it.

JAD: Okay.

[ARCHIVE CLIP, woman: With each step ...]

JAD: Neuroscientist David Eagleman again.

[ARCHIVE CLIP, woman: ... you fall forward slightly, and then catch yourself ...]

DAVID EAGLEMAN: I started wondering, what happens ...

[ARCHIVE CLIP, woman: ... from falling.]

DAVID EAGLEMAN: Why is it that elderly people fall down a lot? If you go into any hospital ward, you'll see lots and lots of elderly people who are in there with broken hips and things like that because they've—they've fallen. I started asking my clinician friends, and they say, "Well, they have a poor sense of balance, muscle weakness," and so on. I said, "Could it have anything to do with timing?"

JAD: What do you mean?

DAVID EAGLEMAN: Well, one of the things I study is how the brain sends out signals to the whole body, and how these signals come back. Because the strange part is the brain is situated all the way at one end of the body, all the way at the top end, and it's controlling this huge amount of machinery. You have to send signals all the way out to the toes and all the way back, and they're surprisingly slow in the brain. It's about 300,000 times slower than signals move around in a computer.

JAD: Hmm.

DAVID EAGLEMAN: So it would be like if you were a NASA operator controlling the Mars Rover, there's a delay between when you send the signals and when you get the feedback. And so what happens is the brain is very—puts a lot of effort into making sure that it knows exactly the timing of sending signals out and when it's getting signals back. And that's how you walk, for example.

[ARCHIVE CLIP, woman: Do you want the camera? Caty, get the camera.]

ROBERT: So this is like what toddlers learn in reverse. Aren't they learning the timings to get the left foot out in front of the right?

DAVID EAGLEMAN: That's exactly what they're doing. They're calibrating the timing of their whole nervous system.

JAD: That's interesting, because my kid's 10 months old, and I think he's in this calibrating period. What's happening with him now is he's standing, but then it looks like he's about to take a step, but then right as he's about to—oh!

[ARCHIVE CLIP, woman: Oh, that was good!]

JAD: So basically you're saying his little brain is trying to figure out the timings of electricity racing from brain to foot and foot back to brain.

DAVID EAGLEMAN: Yes.

JAD: Mission control is going, "Okay, we're sending that message to the feet. We expect it back in 300 millisec ..."

[ARCHIVE CLIP, JAD: Oh!]

JAD: Tumble, fall.

[ARCHIVE CLIP, woman: Take three.]

JAD: Okay, we're gonna try now 280 milliseconds. Okay, 280, go!

[ARCHIVE CLIP, JAD: Oh!]

JAD: Tumble, fall.

DAVID EAGLEMAN: That's exactly right. A lot of trial and error until you get the timing right.

ROBERT: But get it right, now you're a walker.

DAVID EAGLEMAN: Right.

[ARCHIVE CLIP, woman: Three, four. How many—oh my God! You're, like, running!]

DAVID EAGLEMAN: Now something that happens in, let's say, multiple sclerosis ...

JAD: And maybe also when you get old, says David.

DAVID EAGLEMAN: ... is that the timing starts to change because there's damage to the sheathing around the nerves, and that slows down certain signals. So then the brain says, "Oh, I thought my foot should have hit the ground by now but it hasn't. So I'm gonna send out a corrective motor command." And then finally the signal does come back, and you've sent out this corrective motor command, and you'll stumble.

[ARCHIVE CLIP, woman: With each step you fall forward slightly, and then catch yourself from falling.]

ROBERT: Now we're going to fall far from home. We're gonna have to travel a good many light years off the planet to fall in this particularly special and gruesome way. Our faller is Neil deGrasse Tyson, he's an astronomical physicist.

JAD: Is that what he is?

ROBERT: Yeah.

JAD: Here he is at the Herbst Theater—I like saying that. Herbst Theater in San Francisco, in front of an audience talking about ...

ROBERT: Falling apart.

NEIL DEGRASSE TYSON: I'm minding my own business on the airplane, and someone looks and sees what I'm doing. They find out I do astrophysics, then out come the questions, "When will life end? Will the asteroid come? Will the Aztec calendar destroy the Earth?" There's all—there's—it goes on and on, so I figured people like death and mayhem. So I might as well title the book with that because there's a whole chapter on how to die as you fall into a black hole, which I personally think is a kind of cool way to die. Because what happens is the gravity of the black hole is extreme, as you can imagine. Light doesn't even escape, its gravity is so extreme. Light traveling at the speed of light, right? So if light doesn't come out, nothing's coming out. It's black, you fall in, you're not coming out. It's a one-way trip, okay?

NEIL DEGRASSE TYSON: So you don't just die because you disappear, you die long before you disappear. As you fall in, the gravity at your feet becomes rapidly greater than the gravity at your head, so your feet start falling faster than your head does. That's a bad situation to be in. You don't really—initially, you kind of feel good, you know? Because it's—we all stretch when you wake up in the morning. Initially, it feels like a stretch, but what happens is that stretch continues beyond comfort levels, and you reach a point where—and they're called the tidal forces, tides on your body basically. The tidal force becomes so great that they exceed the intermolecular forces that bind your flesh. And so the point comes where you snap into two pieces, likely to happen at the base of your spine. Now you are two pieces. Now I know you didn't ask about this, but it turns out you will survive that snap because below your waist, while there are important organs, there are no vital organs below your waist. So your torso will stay alive for a little while, okay? Until you bleed to death, but this all happens much faster than it would take to bleed to death. So these two pieces then feel tidal forces, and then they snap into two pieces. And then they snap again into eight, and then 16, and then you're bifurcating your way down. And so eventually, it's your head and multiple other parts. And so that will continue until you are a stream of atoms descending toward the abyss. And it turns out that's not the worst of it, okay? The worst—it turns out the fabric of space and time funnels down towards a black hole, so the space that you occupy up here is larger than the space you occupy down here. So in fact, you're getting—while you're getting stretched, you're getting squeezed, extruded through the fabric of space like toothpaste through a tube.

JAD: Well, we're about to ...

ROBERT: Fall away, I think.

JAD: Oh, good! Nice one. Nice one, Krulwich. Before we do though, know that we have a podcast, it's at Radiolab.org. I'm Jad Abumrad.

ROBERT: I'm Robert Krulwich.

JAD: Bye.

[JOAN MURRAY: This is Joan Murray. Radiolab is produced by Jad Abumrad and Tim Howard.]

[FREDERICK COOLIDGE: Their staff includes Ellen Horne, Soren Wheeler, Lulu Miller, Brenna Farrell, Pat Walters and Lynn Levy. Special thanks to Ari Daniel Shapiro, Anne Huang, Emily Corwin, April Kinzer and the City Arts and Lectures in San Francisco. How's that, guys? This is Fred Coolidge, all about the hypnic jerk. Bye.]

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