StarTalk Radio - The Science of High-Wire Stunts with Philippe Petit

Episode Date: October 14, 2016

Put on your safety harness as Neil deGrasse Tyson investigates the world of death defying stunts with high-wire artist Philippe Petit, co-host Eugene Mirman, and guests Charles Liu, tight-rope instructor Sonja Harpstead, and Bill Nye the Science Guy. Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to new episodes ad-free and a whole week early.

Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now. From the American Museum of Natural History in New York City, and beaming out across all of space and time, this is StarTalk, where science and pop culture collide. Welcome to the Hall of the Universe of the American Museum of Natural History, right here in New York City. I'm your host, Neil deGrasse Tyson, your personal astrophysicist for tonight on StarTalk.

We are going to be talking about the physics of stunts, the physics of high wire acts. And we're featuring my interview with the French high wire artist, Philippe Petit. Back in 1974, he walked a wire between the Twin Towers of the World Trade Center, and I had to ask him why. All of that and more tonight on StarTalk.

Let's do this. So I got with me Eugene Merman. Welcome back, Eugene. Hello. Great to be here. My comedic co-host. And Charles Liu. Give it up.

Thank you so much he's a professor of physics and astronomy at the City University of New York on Staten Island that's right and I bring him

on the show anytime there's stuff I don't know quite enough about but he knows everything about everything so Charles there's a lot of physics

in High Wire Act incredible amounts balance gravity rotational inertia okay so this is how you restore your balance. That's right. Right, and so Philippe Petit, it wasn't just the World Trade Towers. Now, I'm a resident of New York. I remember when he did this. It was all over the news, but apparently that's not the only stuff he's walked between, all right? If he sees any two things, he wants to walk

it. So apparently, he walked the Notre Dame Tower in Paris. That has two main towers. He walked between those. He also walked the two uprights of the Sydney Harbour Bridge in Australia. So let's just have a look at his historic walk across the towers. Check it out. There he is. Amazing.

Now that I know he had a pole, it doesn't seem so hard. The pole weighs 55 pounds or so. I can't even lift that pole. I've got the data here. You do. So here we go. So what is it? So it took six years in the planning.

This was not just an afterthought, you know, on a Sunday afternoon. And the cable between the two buildings weighed 450 pounds. Wow. So you have to secure that cable some way while nobody notices you're doing it. And, of course, it's 110 stories above the ground. And he went out there and hung out for 45 minutes. Amazing. Didn't come back.

He just laid down, waved, you know, just walked, turned around, slept. No, he didn't sleep, but he looked very comfortable up there. And so I'm just curious, what motivates somebody to do this? And I brought him to my office, and I just had to ask him, what's up, basically?

Let's check it out. Are you crazy? Hey, mommy. Let's check it out. Are you crazy? Absolutely. Certified. But the capital C is like a beautiful Garamond type with serif. It's noble. It's beautiful craziness. It's not crazy craziness.

Oh. So you've thought about this, how to be crazy in an artistic way. Well, I never thought of wanting to become crazy, but I became a crazy man about details, a crazy man about perfection, a crazy man about doing the most beautiful performance to inspire people. So in that sense, you know, there is a certain noble madness to those performers who inspire us. I like the pair of words, noble madness. Yeah, it goes well together. Yes.

Yes, that works. That works. Reading up on your background, you're a magician, right? Yes. Yes. So when was this transition between the magic tricks that you might do at a party or on a street corner and raising the level of performance art to the high wire?

This is a great question because actually from the little kid doing magic tricks six years old I became the little kid at 14 learning juggling only because in the world of magic the advocate to juggle because it you know open your sensibility your coordination so here I am with no circus school, no videocassette, by myself, learning how to juggle. And then, six, 14, around 15 or so, I put my nose in a variety show, in a musical, in a theater, in a circus, to see more magicians

and to see more jugglers. People pay to do it. Yeah, absolutely. And I see those amazing men and women who walk in thin air, the high wire walkers. And here I am at 16, and I am a self-taught wire walker because I spent my entire childhood climbing with trees, playing with ropes, doing, performing. So I am a born wire walker, and that's, in very short, the story of my short life. Wow.

What a charmer, too, right? Yeah. Yeah, you got that French accent, and it makes it all sound like very, like... So what he's doing professionally is merging that which the laws of physics enable and that which the creativity of art will display. So I'm just curious.

I've met artists that don't think at all about science or precision or accuracy. They do it for the pure love of the art. In my interview with Philippe, there was a scientist deep down inside of him. He knew how he was using the laws of physics for his art. And I was just impressed by that. I have always felt that when you combine arts with sciences,

that's when true innovation comes about. Artistic innovation or scientific innovation? Both. Both. Albert Einstein himself said that imagination was more important than knowledge in the big deal. You can say that when you're Einstein. But when you try to get an A on

an exam, that doesn't work. What he said was very clear. Imagination encircles the world. Knowledge is limited. And imagination is literally an important ingredient in scientific discovery. You can't just toss it aside and pretend that all you're doing is solving problems that already existed. Well, if you're solving problems, Philippe Petit approached the walk between the towers like a scientific experiment. He had attention to detail, much like any of us would perform an experiment in a lab. Yeah, or if we were walking between two buildings thousands of feet in the air. You'd put a little work into it.

It's not just the physics of it, there's also the engineering of how this came to pass. Let's check out my next clip where he goes there. I learned about the towers as they were being built from France. And at some point, I realized, oh, they are about to be finished. I have to run to America to do my work. So I arrived here and I stayed eight months in New York spying on the towers. And I look at all the interview and the movies and the construction. And I was there, you know, disguised and trying to understand the towers. And at some point, some architects, I heard those towers were designed to move three feet, three feet, six feet. So my wire, now I'm talking about an engineer, my wire there

being tied at three ton will tend to prevent the towers to move. I would say to breathe is more human. You know, actually I could hear them in some of my spy visit. I would hear in a staircase a little bit like the bones of the human body creaking, breathing. So if they want to breathe because of a sudden change of temperature, a cloud in front of the Sun, or because of the wind, well it's not my miserable little cable 3 tonne tight that will prevent them from moving. My cable will be pushed from 3 tonne to 30,000 tonne and it will explode and I will evaporate in thin air and I will kill people below. So it was a very serious engineering problem.

How can I put my wire, tighten it, and yet let the tower breathe if they want to? And... Well, and actually the answer to that came from an old man from the circus. So he said, make sure you put some wood around the steel I-beam that you anchor to, so that if the towers want to breathe, what will happen is that the cable will eat the protective wood. Squeeze the wood. You know, of course you will lose tension, but that will be another problem as a wild boar. But at least you will not evaporate and the cable will not break. I did it. I did that and it saved my life. Doesn't want to evaporate in midair.

He said it saved his life. Like, I'm obviously going to walk between the two buildings. That's terrific. There's no avoiding that. And a wonderful example of using old knowledge, the old man coming to tell him, use it this way. And he used it. It's like elephants telling the previous or the future generations of elephants

where the nearest watering holes are, even if they're 100 miles away or 1,000 miles away. We learn. So tell me about the breathing of the towers. What do you know about it? Basically, when you have a structure that's big and tall, they sway. The differential in air flow speeds between what's on the ground and the top can sometimes be 50, 60, or even 70 miles an hour. So that's nearly hurricane force winds. Furthermore, if you have the temperature, as Philippe described, and the temperature difference between, say, one part of the building and another sometimes can be 40, 50, 60 degrees. The combination results in literally swaying back and forth. Even though they're 1,000, 1,300 feet tall,

they could sway three, four feet back in just a matter of seconds. So that's what he's talking about. If he's got a cable that's stretched nicely, tightly through, and they decide to swing three feet this way and three feet that way, that's six more feet.

He goes boing, choom, that's his evaporation. With that sound effect, for sure. That sounds like a cartoon sound effect. He'd probably yell, Well, he would look down, hold in the air for a second, not realize he was going to drop, then notice

he's over in the air, and then he'd fall. Like Wile E. Coyote. Falling from that height, by the way, takes just under nine seconds. By the time he hit the bottom, it would be 180 miles per hour. On the other hand, if he hacked a loogie that far down, no problem. Because

by just a few feet, it would reach terminal velocity and gently float down like raindrops do. He's talking about phlegm. Yeah, that part I got. I'm just trying to figure out, can he turn himself into spit and then be fine? I think the answer is no.

So what's interesting to me is for any given tension in a wire, there are things that affect that, such as the weight of the wire. Yes. How heavy the person is. And you combine these two, that should affect how he designs this walk. Literally everything had to be designed. The cable is steel, usually, and it's about three-quarters of an inch thick for most high-wire things. I think that was probably the diameter he used as well.

And as you said earlier... If it's too wide, then you're just walking on a... That's right. You're just walking on a road. That's right. It's called a bridge. Yeah, a bridge. A bridge, yeah, yeah, yeah.

And as you said, it was more than 400 pounds. So that means the stretch distance is about 140 feet, which means that every foot was almost three pounds worth of metal. So all of this has to be calculated. And if you're a particular length and you're going to stretch three feet plus another three feet, it's got to be able to accommodate that slack. That's right. And that's why that wood around the I-beam that he attached it was so important. Because as he said, if the cables stretched or they came loose, it stretched

this way, then it would actually dig into the wood. But it wouldn't be able to dig into steel, but digging into wood makes it okay. Why does it make it okay to dig into the wood? Because then the steel doesn't snap the cable. So you have a little bit of give. And as he described in the clip, indeed, he has to adjust for the change in tension and all the things that happen. But those are not fatal failures. Those are things that happen. Yeah, that's a good point.

If you don't have something that can respond to the change in length, then something breaks. And that would be ugly if it happened that way. That's right. Yeah. Yeah, and also something many ugly if it happened that way. That's right. Yeah. Yeah, and also something many people see but might not think about, every single bridge has brakes in the roadway to enable expansion and contraction of the roadways. Every time you drive over the George Washington Bridge up here, it goes,

da-dum, da-dum, da-dum, da-dum, da-dum. He lives in New Jersey, so that's why. Yeah, he's like, why would we ever have that experience? Also, where was I? I was in San Francisco, and there was a park that has a telescope with a caliper inside, I mean, like measuring lines inside of the view of the telescope, and you're looking at the Golden Gate Bridge. And you get to measure, like, was it the curvature or the uprights?

There's something you're looking at, and you see how much it has bent, and it tells you what temperature it is outside. Wow. Yes, it was very cool. Yeah, you're watching the physics of the bridge respond to the temperature, and if it can't respond to the temperature, something breaks. It's the world's most expensive thermometer. Yeah, what a weird way to tell temperature in San Francisco.

Yeah, just pull out your iPhone, right? So more on the physics of high wire feats and how the high wire worker Philippe Pet, pulled this off when StarTalk returns. Welcome back to StarTalk. We're talking about the physics of that high wire walk between the train towers in 1974 by Philippe Petit. And let's check out my interview with the man himself. Everyone's first question would be, how do you get a wire from one building to another? If the wire is strong enough to hold your weight, not that you're heavy, but if it's strong enough to hold your weight, you can't,

you're not, you can't just feed it. Okay, well, in the case of the World Trade Center, how do you pass the cable across? Silently and quickly. Because it was illegal. That's how you do it. But you know what? I'm going to answer with a visual thing because I did something I never do. No, you haven't. I brought the historic bow and arrow. This is the?

That's the bow, that's the bow, which is actually a cheap plastic thing in two parts, which was hidden in a blueprint tube because my friends were disguised as architect. And that's the arrow, and I know the scientist in you is not going to ask me, what did you pad at the end? It's obvious, right? Because you're shooting to someone else on the other side.

My accomplice on the north tower shot the bow and arrow, to which was attached a fishing line. So imagine that in the middle of the night, crawling on the south tower in complete darkness. You're looking for a fishing line that in itself is a movie scene, which is actually in the movie. And this is, you know, this was from my trunk, and you're the first one.

I let you touch it for a few seconds. Thank you. So, anyway. Okay, so now that's the fishing line, and presumably, at this point, the cable is just dangling straight down. No, the cable is still in a south tower, ready to be paid off.

And what I need when I got a fishing line, I need to pay off a fishing line, I need to pay off a cordina, a little rope. And then they got the little rope and they attach a big rope. They send it to me and to the big rope I can attach the very heavy steel cable. So it was like all night of rigging. Because the fishing line is not strong enough to hold the weight of the cable, but it connects you. Exactly. It connects. It creates, it's the engagement ring before the marriage. I love that you say that because very often the poet in me cannot resist describing what happened by saying, I saw the Twin Towers being born.

I had the idea before they were born. I saw them grow up and when they were adult, I married them with the smile of my catenary curve. So marriage, ring, we're all in the same story. Yes, yes, it's romantic, indeed. Well, friends are very romantic. Wonderful. He used that magic word, catenary. Catenary. Catenary.

Catenary. So, Charles, let's talk catenary. Okay, you've got a rope there. I've got a rope. You suspend it. I can suspend it from two ends. And the shape it makes is called a catenary. Okay. You've got a rope there. I've got a rope. You suspend it. I can suspend it from two ends. And the shape it makes is called a catenary. Very nice.

Not a parabola, but a catenary, and it's actually a hyperbolic cosine shape. I knew that. Yes, you did. Plus, it turns out that a catenary is really nice for hanging things and constructing things because there is no extra what's called moment of curvature. It's being pulled in no extra direction more than just its natural hanging. So suspension bridges, for example, they have one huge catenary cable between the two piers. And then from that cable is suspended smaller cables which hold up the roadway. It's a light yet strong way of supporting a tremendous amount of weight

without doing a whole lot other than just hanging a chain. So basically gravity pointing downward against a flexible cable creates this shape. That's right. And so I'd forgotten that, of course, the large suspension cables between the two uprights of a suspension bridge, they're holding a catenary shape. That's right. I'd forgotten that, so thanks for reminding me.

Oh, no problem. So basically, this is too limp for him to walk across. Yes. So he's got to do it tighter, but this is still a catenary. That's still a catenary. Still a catenary. And even if I pulled it really tight... That is a true catenary, also known as a line.

No, but there are other examples that we know of. For example, if I remember my athletic data, the center of a tennis net is six inches lower than the edges of the tennis net. That's right. Which is why you always want to serve through the middle, then you get a really low serve. Yes, exactly. But it's accommodating the reality of the catenary drop.

Yes. Of the cable that's holding up the net. That's right. And, here's Charles, maybe you didn't know this. So in the town of Sèvres, France, there's the International Bureau of Weights and Measures. That's where they keep the kilogram, the meter, the stuff out of which everything else is measured. Now here's what freaked me out. Now the meter

is not defined by an artifact. But when it was, they're showing me the shape. And here's this meter. And you're supposed to support the meter on two points. And then you measure it with a microscope. And then you scale anything else to that to make your other meters.

He said, you got to put the support points here. I said, why? Because that is the distance where they have calculated the effect of the sagging of the weight of the meter under its own weight between these two points. I said, it's only this big. Of course, if you measured it to microscopic scales, you will see the sagging of this rigid bar, platinum iridium bar. And so even that is a catenary. Amazing.

All right, that's what I was going to say. Exactly. I'm glad we cleared that up. Yeah, yeah, yeah. Woo! So more on the physics of high wire walking when StarTalk continues. Welcome back to the American Museum of Natural History. You're watching StarTalk.

And we're featuring my interview with high wire artist Philippe Petit for his famous walk across the Twin Towers in 1974. He used a 26-foot long, 55-pound pole to balance himself over that wire. I asked him how that works. Let's check it out. May I actually tell you what a balancing pole is from my point of view? It is not a trick, little toy to stand you on the wire. It's an extension of your arms because the human being on a high wire, when the winds are, you know, devouring the void, when the building or the landscape move and all that, you are being assailed by destroying equilibrium parameters. All around you. Absolutely. And even inside you. parameters. All around you. Absolutely, and even inside you. So the arms are nothing less than too short and not heavy enough. So the extension of the arms throughout 4,000 years of history of

wire walking became what is known as the balancing pole. So it's a little help. And if I show you how to walk on the wire, which I did for the young actor who played in the movie, you won't be able to negotiate that pole. That pole will move you left or right. It's easier to go without pole. But the minute you know how to negotiate the pole, it becomes like driving a car. You don't really know what you're doing. You're talking to your friends. You're looking at the landscape.

But your hands are constantly balancing left, right, left, right in a very small way. And that's what the balancing pole That's right because as the carts drifts ever so slightly Experienced drivers are not even conscious of the fact that you're bringing the car back exactly turning the wheel just exactly so the same for the Why Walker if you would? Focus very you know with a with a magnifying Camera on a wire worker you will see that he or she is constantly moving because balance is a dance.

Chuck, let's unpack this. I've got the famous cork with a nail in it. This is a Brad. This was a very nice French wine, by the way, for the occasion. I've got my French cork. I've got two forks

and I just dig one in like that and put it in like that this we do this in physics class all the time yes like physics 101 classic demonstration classic demonstration and there you have it balances that's right so what's the physics of this charles well the way that all balances or levers work is that what's called L1M1 on one side has to equal L2M2, which is on the other side. Yeah. And all that really means is that— We're waiting for what it really means. Yeah, yeah. All it really means is if you have a longer thing on one side and the other side, small changes in your balance will be more easily balanced out than if

they're shorter. So when Philippe was talking about his arms being too short, that's exactly right. As soon as he tips a little bit, he's going to swing all the way down and he can't bring enough lever arm on this side to balance him over. But once he has that 26 foot, 55 pound pole there, he's presenting himself with plenty of options in order to get himself back in balance by having that long lever arm on both sides. So now this is actually a different case from what you described because this part of the fork is sitting below the wire. That's true. So if this wants to tip, he has to lift the center of mass higher than what it was before, and the center of mass doesn't want to do that.

The center of mass of any system wants to stay as low as possible. Now, I asked him about this in a part of the clips we did not use, and what he said was, well, this is just a physics toy. You can buy this in a store. And a physics toy, is he just a physics toy up there who can't fall? Is he a physics toy? And he said, no, he's not a physics toy because he's using his balancing talent

and the bar as an extension of his arms to maintain balance, not as a physics toy such that he can't fall over at all. That's right. And I said, well, I'm a little skeptical until I saw the pictures of his bar. And when you look at the pictures, they do not sit below him. They do not go below the wire.

That's right. The way these do. So this is a physics toy. He's not. Wait, could you have a wire that, or a bar that was so long and weighted in such a way that you would almost definitely not fall? Yeah. Yeah, so for example, if he had a really long bar that sunk well below the wire that he's walking on, as he begins to tip, the center of mass has to raise up for him to tip.

And it won't let him do that. It'll just right him back. Again, he might misstep and he'll fall because he misstepped. But if he falls, it's not because he lost his balance if he had one of these configurations. And so this is very stable. And I can just balance that right here. This is slippery. It's slippery.

Give me something to put this on. There we go. Yeah, so. I am no longer impressed by that guy. Yeah, so, I mean, he knew this, and we chatted about why this is not him. And notice this is below the level of the bar, below the level of the wire.

And if he falls, he's lifting this weight to a higher point than it was before. And that's just not going to happen. We break it off. Yep. I think his arm fell off. This is the physics of it, but Philippe Petit, he not only knows the physics,

and he's got that, he takes it a step deeper. A step deeper. In his mind, body, and soul. Let's check it out. I will never agree that this mystery of balance can be explained a step deeper in his mind, body, and soul. Let's check it out. I will never agree that this mystery of balance can be explained and put out in a question on a blackboard. I would say that this is something that will never

be put in a question. The human passion, the human intuition, the human tenacity, and therefore balance is a mysterious chemistry that even you, and I don't mean to insult you, I mean to respect very much science, because I love science, but never... Insults welcome at all times. ...it could be explained in a scientific way.

I mean, yes, we can look at the muscle and the nerve and the blood flowing, but what about the soul? What about the poetry in your head? What about things like, I refuse to understand that something is impossible? Can you put that on the equation on the blackboard? No, you can't. You can't. Good. tree in your head? What about things like I refuse to understand that something is impossible? Can you put that on the equation on the blackboard? No, you can't. You can't.

Good. At the same time, I am a lover of science. And I was a kid, I realized, I was told that what is science? Well, science is not a vague notion floating above your head. Science is experiment. Do this experiment 20 times, write downvez 19 par 20 fois la note qui a été cassée, et puis vous créez lentement un paramètre, une règle qui peut être vérifiée, et vous grandissez avec la civilisation, et vous avez tous les types d'expériences plus sophistiquées,

avec des mesures plus précises, et c'est en fait une expérience, c'est une erreur de trial and error. J'adore la science parce que c'est humain, c'est nous qui sommes au travail pour essayer de changer And it's basically experiment. It's trial and error. So I love science because it's human. It's us at work in trying to change the question mark around us into exclamation point. I love when you are speechless. He first said it wasn't science, and then he said it was science. Yeah.

It's just complicated science. When we're dealing with psychology, all the hundred billion neurons in your brain and being able to map those out in simple equations, that is still impossible. It's true. If you tried to break it all down, you were able to, then that would still be science. But what he said about science being something turning question marks into exclamation points, I don't know if I've heard a more poetic and beautiful way of explaining what science is all about. Ooh. Well, up next, the psychology of attempting and surviving such death-defying stunts as he performed on StarTalk.

We're back in the Rose Center for Earth and Space talking about the physics of high wire acts, the physics in the mind, body, and soul of Philippe Petit. And I always wondered, I got the physics, but what kind of mind does it take to do what he's doing, to step out on that wire? Let's check it out. I have to be certain on the first step, I have to have a physical and a mental certitude

that I will successfully perform the last step. If not, what am I doing? Well, I am full of doubt and fear, and I am risking my life. Well, I value life much more than that. I will never risk my life, or that of the building, or that of others below. J'ai beaucoup de doutes et de peur et je risque ma vie. Je valide la vie beaucoup plus que ça. Je ne risquerai jamais ma vie, celle de l'établissement ou celle des autres. Donc, quand je suis sur le fil,

j'ai créé des milliers d'heures de pratique, des dizaines d'années d'expérience. J'ai créé un focus et une concentration qui n'ont pas d'équilibre et je n'ai pas de recette pour les autres. C'est ma propre petite chimie. concentration that has no equal and that only I have no recipe for others. It's my own little chemistry. It is a very strange mood that really is physical. When I grab the pole, I am not wobbling. I am solid. And yet I'm doing the most fragile action on earth. I am a miserable little human being who extracts itself from

gravity and who is now balancing and wants to become a half man, half bird. How presumptuous. But that only can happen if there is this, I go back to poetry, but this sense of theater, this sense of performing, this sense of measuring yourself with the elements, a little dash of humbleness, which is not my specialty, but anyway, so that you know that you're not invincible. The minute you think you're invincible, you're going to die. You know, that's what you deserve. But if you have a little dash of humbleness and if you feel that you are controlling your

life and the world, you see, it's a very strange, fragile chemistry, then you will give the image of solidity and majesty and panache and arrogance. life and the world, you see, it's a very strange, fragile chemistry. Then you will give the image of solidity and majesty and panache and arrogance. Why not? You know, but beauty and beauty, the real beauty inspires people. Yeah. So there's an interesting dimension to this. Why do we watch high wire acts at all? Unless we are thinking they might fall and that'd be something interesting to look at. Isn't that a weird thing? Well, it is true.

We can talk about his psychology, but what about the psychology of the people that are attracted to watch the thing in the first place? Well, I think I might catch them. Really? Yeah, no. The humility that he describes is so correct and true. He has to be, on the one hand, confident,

and yet the other hand, understanding that he is one thing amongst others. There have been a number of tragedies in the history of High Wire. Probably the most famous name in High Wire, the Walendas, the flying Walendas, Carl Walenda himself, he died during an ad performance.

Well, so Philippilippe petite asserts that takes a special focus maybe even a supernatural that's the way he's speaking he's pulling his focus from someplace none of us have ever seen or dreamt of and it just so happens we have on our video call i think we've brought in, we have someone who's a tightrope instructor, Sonia Harpstead. She teaches at the Circus Warehouse here in New York. Sonia, do we have you on the line? Yeah, I'm here. Oh, Sonia, hello.

Thanks for being on StarTalk. Hi, it's great to be here. Yeah, so we know intellectually that people such as yourself exist. But to really see you, you teach people high wire stunts. So what kind of mindset does it take to, who comes to you to do this? That's really what I should be asking here. Well, you know, the funny thing is that a whole range of people come to us. And it's really interesting to see who's interested in the challenge.

We teach the wire's not that high, so it's not a fear thing. It's really more about finding a way to get your body to do something that's really challenging. So are you saying you can actually teach this skill? It's not just some psychological state of the person who finds you? Well, a little bit. You also teach the psychological state, but you can absolutely teach tight wire walking. Anyone can walk a tight wire. And when did this begin in your life? When I was in high school, I went on vacation and they had a flying trapeze there. And when I jumped off, I just knew I was

going to do this for the rest of my life. So I found some classes and I worked on it through college. And at the end of undergrad, it was med school or the circus. And I chose the circus. So you tell me by probably by age 17, you were in a position to tell your parents you want to run away and join the circus. That's what you're telling me here. Yeah. Very cool. Well, Sonia, thanks for sharing some time with us on StarTalk. Thanks for having me.

I'll come watch you one day. Please do. And we'll take physics notes and we'll compare notes. Absolutely. We'll tell you what law of physics kept you alive and what would have killed you had you one day. Please do. We'll take physics notes and we'll compare notes. Absolutely. We'll tell you what law of physics kept you alive and what would have killed you had you messed up. Okay? All right. Thanks, Sonia.

Thank you. All right. More of my interview with legendary high wire artist Philippe Petit when StarTalk continues. We're back on StarTalk at the American Museum of Natural History right here in New York City. We're featuring my interview with high wire performer Philippe Petit. He's French. And he walked between the World Trade Towers in 1974. And I had to ask him, is there a difference between walking on a wire 1,350 feet above the ground or working on a wire 10 feet above the ground? Check it out. There is a continent of difference between walking 10 feet high, 10 stories high, and walking between the highest

towers of the world at the time. And yet, for a scientist who analyzes balance, it's the same thing on the floor, you know. Yes, scientifically it's the same thing. But no, it's not because to walk on the wall you have to not be devoured by the space, by the void. And when we say void in any language, you know, le vide, it's a nice word, you know, people think it's empty, there is nothing. Well, you scientists know the void is full of surprises, full of myriads of molecules floating.

The void is a continent that needs to be explored. So here I am in the void, and the void is voracious because human beings are made by gravity. You cross voracious voids. Well, what I tell you is because human beings are made by gravity. You cross voracious voids. Well, what I tell you is because human beings are made to, I wouldn't say crawl on Earth, but I mean live on the surface of the Earth. You know, very few people are going in the belly of the seas,

in the mouth of fire of a living volcano, on Mars, in the moon, on a high wire between the Twin Towers. So when you venture in these inhuman, inhuman boundaries, then you find out the whole world is against you in some ways. So you have to have a certain tenacity and courage and sense of poetry to majestically walk in those voids. So are you guys afraid of heights? I'm going to say yeah, and certainly that high.

You'd be afraid of that height. Ten feet up. Yeah, I've done ziplining and accidentally did it where you were like, I don't know, like three-quarters of a mile in the air or something between mountains. It was very terrifying. So, zipline where you... You hold the thing and they're like, don't worry, you won't die. And then when you're doing it, you're like, are you sure?

And you're sliding along a cable. Yeah, yeah. But then you get stuck sometimes. It's great. This is one of the ways they had people escaping the launch vehicles in Kennedy Space Center. Yeah, you have to do it. Definitely do it. But it was not just a zipline to get you away from the spacecraft.

It's a zipline that takes you basically to a bunker because your spacecraft is about to explode, and you've got to be protected from that. How often did they do... They've never needed it. Oh. I mean, good. Yeah, yeah, that's right. No, I love ziplines.

Being harnessed, being tied to something like that, no fear at all. I could be a mile up. What freaks me out is when I'm looking over the edge of something, and the only thing between me and 1,000 feet down is a rail. And I look over, and I know intellectually I'm going to be just fine. But the butterflies, they just go. There's a natural, oh, crap.

That's what the butterflies are saying. Okay. Eugene, where were we? It freaks me out when I look over the edge. It's simple as that. I'd be afraid to tightrope that. Yeah. But other things. Fair enough.

Other things, I don't really, I'm cool with heights. I grew up in the city, and tall buildings are just life. And I lugged my telescope to the roof of my 22-story building, and I looked over, and little people down there walking. And I loved going to the tallest buildings that I could at the time. But do you, like, looking over a railing, I agreed, mildly terrifying. What about, like, flying through the air or being in a precarious, like, so far you're're like I don't mind being

at the top of a building. I also am comfortable with that. Okay, yes. So, no, no, but you can split it. There's the risk of thinking you're going to die because the railing is frail and just being at a high height. Right. These are two different things. It's probably evolutionarily

you want to fear heights because you don't want to fear heights. That's right. Because you don't want to die. Psychological experiments have indeed shown that when you have toddlers or young children going to the edge of something that's high, they naturally have a fear response. Well, so what's interesting, we researched some other creatures in the world. Yeah. And here we are, like, impressed with high wire walkers, yet in the animal kingdom,

are any of us impressed by a squirrel just runs along a power line? Well, they're small. No, no, no. They're just running along. They're going back and forth chasing each other on a power line. If you saw a horse doing that, you'd be like, wow. Okay. All right.

All right. Not impressed with the squirrel. How about the mountain goats that are just positioned on this much rock, exposed rock on a rake thing, and they're just chewing their cud or whatever they chew, looking around like it's not even a thing. That is very impressive. A lot of them fall, you know. A lot of what? A lot of mountain goats and stuff fall.

How do you know this? I've never seen one fall. You just don't see that on National Geographic. Is that true? Wait a minute. This is the National Geographic channel. Oops. You don't see that on Nova.

Is that a little true that a lot of the goats fall? Because I've seen them. They seem very balanced. It is a little true that mountain goats, bighorn sheep, et cetera, fall often. But what they're really good at- I have to say, if we ever saw that, that would just be hilarious. Yes. I mean, we laugh at kittens that fall off.

They jump and then they fall. Yes. We make sport out of that on YouTube, right? So a mountain goat falling. No, I don't know anyone who has footage of a mountain goat losing its footage. That's right. What mountain goats are great at... Did that sentence make any sense?

Yes. I mean, also... Footing, footing. That's right. What mountain goats are great at. Did that sentence make any sense? Yeah. I mean, also. Footing. Footing. No footing of a mountain goat losing its footing. Right. Right. No, mountain goats, bighorn sheep, they fall often.

We don't see them, of course, on nature specials. Therefore, how do you know they fall? Statistics. People actually do this research, do show that they do fall. But what they're really good at is recovering. They'll fall a ways. It looks like they will go down to their doom, but they're able to recover and catch themselves on the next ledge down.

They don't have thumbs. They have hoofs. How do they catch themselves? You know those horns? No, no. Okay, think, think. Big horn sheep. They've just got four hoofs.

Big horn sheep. Big horn sheep. Catch their head on a wedge. And they're not apes that have, like, rotating, rotator cup shoulders. Big horn sheep. Yeah. With the horns. Yeah.

Squirrels with their tails. They're almost like built-in bars. They're extra lever arms to the left and the right that allow them to have better balance than we otherwise would. Wow. So those big horn sheep are the French of the...

We miss you. But we can go even bigger. We get to elephants. Yes. You have elephants balancing on balls and stuff like that? In the wild. In the wild. What's in the wild? Well, that's just practice. I haven't seen it in the wild. But now you don't see many elephants

in circuses anymore. But when we did, they'd be balancing on balls. So why should we be impressed if we do it? Well, if it's high enough, I think it's impressive. Yes, if an elephant were on a cable balancing on a ball, we'd be impressed When an elephant gets to the top of a On the side of a cliff, okay

But if an elephant walked a tightrope holding even a small pole In its little trunk Yeah, in its little trunk I'd be like, alright elephant, now this is something Now you're talking in its little trunk, I'd be like, all right, elephant, now this is something. Now you're talking. Well, coming up on StarTalk,

our StarTalk episode is not complete without a dispatch from Bill Nye the Science Guy when StarTalk continues. Welcome back to StarTalk. We are featuring my interview with high wire artist Philippe Petit, who walked between the twin towers of the World Trade Center. I always wanted to know what's next for him. Let's check it out. So after that, some people said, well, what now? The highest towers in the world. Are you going to kill yourself? You're going to retire? No, I was not

collecting the gigantic. I was not interested in this absurd competition that the book of records, you know, offers. I hate that. No, it's curiosity, but noble curiosity. It is the feeling that we all have when we are born that we want to maybe extract ourselves from our human condition. That's why people go on space and visit other planets. That's why people try to fly. That's why War Walker exists. So the competition on those technical terms is absurd.

What is beautiful is the intellectual risk, you know, the breaking boundaries, surprising yourself. You know, we take ourselves so seriously. We never make a fool of ourselves. We never go in directions that are not the one that we feel we are. If you like classical music, are you listening for a few hours to heavy metal? Probably not. Well, I do.

I sometimes play with the extremes. I explore. And again, you see, I always use the word exploration, curiosity, intuition, because that's what I think we should do in our very, very short stay on this planet. Charles, he's really a scientist. He really is. He's talking right now about the innovation,

creativity, imagination. What's interesting to me is he's not doing this to set records. He's doing this as art. And he's asking himself, how can he extend the boundaries of his art? And that's a noble cause. That's what any artist should be doing. And that's what every scientist does, too.

Looks at what's there and says, what's next? So before we wrap, we've got to catch up with my friend, Bill Nye, the science guy, with his latest dispatch from the city. And he's going to be reflecting just on what all this means. Check it out. We're on the grounds of the World Trade Center. This is where a national tragedy occurred. But the building that stands here now is inspirational. When you're in here, you feel like you could soar like a bird over the city of New York. This is also where the Twin Towers once stood and where Philippe Petit managed to rig a wire 1,368 feet above the street. And he walked that tightrope for almost an hour one morning.

above the street. And he walked that tightrope for almost an hour one morning. People on the ground were riveted. They were amazed by this man who seemed to be flying over the city. When you come here now, I hope you get some of that same feeling. I hope you're inspired. So thank you, or merci, Monsieur Petit. And thank you, Mr. Big Building Train Hub. And thank you, Mr. Big Building Train Hub. You inspire us. When we come here, we feel like our imaginations can soar. This is what architecture does. A great architecture soars, and it forces your imagination to soar along with it.

And what's interesting is that in this particular case, what did he do? He walked the World Trade Towers, and one of the nation's greatest tragedies occurred on that site, and we all know this. And when I try to remember the towers, because I live near them, it happened in my backyard, the September 11th attacks. You know what I do?

I look at the towers and I say, okay, these aren't just buildings to me. I have the lens of an astrophysicist. So they mean something else. They mean something more to me. First, there were a veritable indoor universe unto itself, multiple levels below ground of shops, hundreds of shops, 110 stories up. You'd reach the roof. At the top level, there was a little computer where you could

type messages that would be sent out to aliens from the radio transmitter that was at the top of the North Tower. So in a sense, the tower was trying to sort of help us reach for the stars. And that meant a lot to me, even though I knew nobody was probably listening or anyone would care. It was the gesture that mattered to me. And then I'm there at sunset. And at sunset, the towers are so tall that you can actually watch the sun set floor by floor up the building. The building is so high that from the top, the sun sets nearly

two minutes later for someone at the top floor than it does for someone at the bottom floor. That's how much beyond the horizon your view was granted from that height. And so, in fact, if you could run up the stairs one floor per second, you could stop the sunset in its tracks because you'd be ascending at the same rate that the sun would be setting. And you'd run out of breath or run out of floors. Eventually, that would have to stop. And then the sun would set on the World Trade Center. So yes, the sun has forever set on the World Trade Center.

But the sun has risen and set a trillion times before. And though it is set on the World Trade Center, it'll continue to rise and set for the rest of the time we have on Earth. And he married them. The science, the physics, the astrophysics, the poetry. What more could we ask for a pair of buildings that are no longer there? That's our show. As always, I bid you to keep looking up.