Physics Freestylin’ with Charles Liu & More

What are the physics present at the Olympics? Neil deGrasse Tyson and co-hosts Chuck Nice and Gary O’Reilly with the help of Charles Liu, explore the science in some of the newest additions to the Games with pro-breakdancer RoxRite and freestyle BMX rider Nikita Ducarroz.

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

• 0:00Neil deGrasse Tyson?

  This is StarTalk special edition. Neil deGrasse Tyson here, your personal astrophysicist. I got Gary, Gary Riley. How you doing, man?

• 0:09Gary O'Reilly?

  I'm good, man. It's good to be on again.

• 0:11Neil deGrasse Tyson?

  Very good. And Chuck, of course.

• 0:13Chuck Nice?

  Yes.

• 0:13Neil deGrasse Tyson?

  Chuck Nice, calling in from wherever in the universe you might be this moment.

• 0:17Chuck Nice?

  In my skin, in my skin. Where I wasn't. I was not in my skin, Doug.

• 0:21Neil deGrasse Tyson?

  You were not in your skin. I'm not even my ass. Hmm. That's another conversation.

• 0:25Gary O'Reilly?

  That's a new episode.

• 0:28Neil deGrasse Tyson?

  So Gary, you're a resident athlete and a resident professional athlete. So I was never paid to be an athlete. So what did you tee up today?

• 0:38Gary O'Reilly?

  Well, we got an Olympics coming up fast and it made us think. But because it's us, we have to think slightly differently.

• 0:47Neil deGrasse Tyson?

  StarTalk, we badass when we do stuff.

• 0:49Gary O'Reilly?

  Today, we're going to get into two sports. One's making its debut in the Olympics in Paris. The other one made its debut in 2021 in Tokyo, the delayed Olympics. One is considered to be an art form and a lifestyle. The other one rolls around on wheels. So if you haven't guessed it already, this is going to be breaking and BMX.

• 1:11Neil deGrasse Tyson?

  With breaking, is that what I remember as breakdancing?

• 1:14Gary O'Reilly?

  Yes, but the dancing has in time disappeared. Once we've spoken to these two athletes, we're going to stick it in a physics blender that we'd like to call the Geek in Chief, Charles Lu himself. And then from that, we will explore exactly what's going on in these two sports.

• 1:34Neil deGrasse Tyson?

  I'd love with the Geek in Chief, my wingman, or when he's on the show, I'm his wingman. That's how that, that's how that goes.

• 1:40Gary O'Reilly?

  Whichever way you want to play it.

• 1:44Neil deGrasse Tyson?

  Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now.

• 1:56Neil deGrasse Tyson?

  We got in the house Roxrite.

• 1:59Chuck Nice?

  Roxrite.

• 2:00Neil deGrasse Tyson?

  X R I T E. Roxrite, a breakdance legend.

• 2:04Speaker 03

  Thank you guys. Thank you for having me. It's a pleasure to be here.

• 2:07Neil deGrasse Tyson?

  You, you have a hundred victories? So these are like full up contests with like trophies and things? Is this, is this how that works today?

• 2:15Speaker 03

  Basically a tournament of sixteen, around sixteen. So you go through the whole tournament and that's what I count as a victory, the full term memory in my each battle by itself.

• 2:23Neil deGrasse Tyson?

  Oh, oh, that's all the whole tournament victories.

• 2:26Chuck Nice?

  Damn, you're like, there can be only one and it's me.

• 2:32Chuck Nice?

  Yeah, I don't, I don't take, I don't take a victory lap for one battle. I gotta take the whole thing.

• 2:38Neil deGrasse Tyson?

  So Rox, if I, can I call you Rox? Is that?

• 2:40Speaker 03

  Yeah.

• 2:41Neil deGrasse Tyson?

  Run a first name basis. Rox, I mean, I'm old enough to remember when this stuff landed, right? Back in the late seventies, mid seventies, if you're really deep in there, what is breakdancing's connection back to hip hop?

• 2:57Speaker 03

  Well, I mean, the connection to hip hop is the first hip hop dance. So when, when hip hop was put together as a cultural, like it's the culture and they had the elements of hip hop from DJing, MCs, street art, and then the dance was breaking. So from the very beginning, breakers were there at the parties and that's where it was discovered. And from there on, it reached different people and they started developing it and getting it to grow more and more throughout the world.

• 3:22Neil deGrasse Tyson?

  That's how you know it's a real cultural phenomenon because it, it touches so, so many people. So what triggered your interest? And you're based in Los Angeles, right?

• 3:32Speaker 03

  Yeah, yeah. I'm based in Los Angeles, but I started actually dancing in a small town north of San Francisco. In 1995, I just saw a bunch of kids doing it at my school. And I just thought it was the coolest thing I ever saw and the way that they would spin, it just caught my attention and right away I just started trying it, went to a friend's house. Started breaking on carpet first.

• 3:52Chuck Nice?

  Carpet first.

• 3:54Speaker 03

  First on carpet.

• 3:55Gary O'Reilly?

  Smart move.

• 3:57Chuck Nice?

  Yeah, that's that's the way you ease your way into it.

• 4:01Gary O'Reilly?

  Okay, so you you you're starting to do this thing in the nineties. Did you ever imagine breaking would become an Olympic sport?

• 4:09Speaker 03

  To be honest, I never thought I would see it in my lifetime, because when I started, I mean, in ninety five, there wasn't so many people doing it. It had been considered dead for so many years in the States that only certain people that knew about it or in certain communities, they were doing it and they kept it alive to just parties and, you know, kids that just did it every now and then. So for me, it was it was something new. And when I started at that time, there'd be guys from the eighties that still were active in some way in the community. And they always talked about breaking being in the Olympics. They would always mention it should have been in the Olympics. It should have been in the Olympics. So for me, in my lifetime, I never thought I would see it. So when they told me that it was gonna be happening, it just blew my mind.

• 4:48Chuck Nice?

  How do they qualify you for the Olympics? Like, are there ten sets of moves that you have to be able to do that they judge? Or is it like X Games where you put together a routine and then they just, the people who know, you know, the kind of like verbiage of the or the language of the movements, they just say, oh, okay, this is, you know, this is how great that was, or how do how do they judge?

• 5:18Neil deGrasse Tyson?

  Right, right. Some of the history of that was, as I understand it from my nephew who studies this professionally, that some of the breakdancing was an art form as a substitute for a gang fight.

• 5:32Gary O'Reilly?

  Yes.

• 5:33Chuck Nice?

  Wow. Yeah, break battles, yeah.

• 5:35Gary O'Reilly?

  It was a dance-off.

• 5:36Chuck Nice?

  Battle breaking, yeah, it's a real deal.

• 5:38Neil deGrasse Tyson?

  Right, right.

• 5:39Chuck Nice?

  Same same thing with MCs. That's, you know, instead of fighting, MCs will come together and basically lyrically, you would battle and you would show that your dominance on the mic was a metaphor or representation for me kicking your.

• 5:56Neil deGrasse Tyson?

  It's still good if you could kick their ass anyway.

• 6:02Speaker 03

  You had a few metapoles.

• 6:03Neil deGrasse Tyson?

  So let's pick up from Gary's question then. This ascends to the Olympics. Somebody has to make the rules around it. So that the world can participate with the same set of expectations. So who set that?

• 6:16Speaker 03

  I mean, there's a system was developed for judging the dance publicly at the Olympics because people from the community were getting together and we're creating a format to where you can keep statistics of the rounds that were being scored in tournaments. Because we wanted to see the results before people would just point and give you their opinion. Now we have statistics where they can keep track of what rounds you were voted for or against. Then you can have a better idea of your performance round for round. For the Olympics, this is where they developed a judging system format. Where they can give you feedback and information as to how you performed. As to what you asked about, how does somebody pick a winner?

• 6:56Speaker 03

  There's a lot of different moves. You don't have a choreographed routine because most of the time you don't know what the DJ is gonna play. He's gonna put the song and you have to adapt in the moment on the go and adjust your moves as you move. Some dancers that break, we choose to have sets, which means you choreograph beginning to end what you're going to do. Or you have people that freestyle movements that they already know how to do, right? And this is more to the roots of the culture and the dance because it was created as a sporadic form of dance. Where movements we just done in a sporadic form. So that is a style that is in many ways, many people are utilizing today. So they'll adapt in the moment with the music. Or they'll adapt their whole round based on what they see.

• 7:38Speaker 03

  And as you're performing it, there's many things that come into play from execution. How well your moves connect? How well you're taking the point now in the battle.

• 7:46Neil deGrasse Tyson?

  Choreography, yeah.

• 7:48Speaker 03

  Yeah. How well you're battling? So they took all these things into consideration. And then from there they score it and as well the tournament goes on and progresses. Uh repeats, crashes, those things take points away if you start to repeat the moves.

• 8:02Neil deGrasse Tyson?

  Right.

• 8:02Speaker 03

  Same exact moves you did already. If you start to make small errors. Uh those things matter and then that can cost you the battle.

• 8:08Neil deGrasse Tyson?

  How did they know it was an error? Maybe you did it on purpose.

• 8:11Speaker 03

  And sometimes you can make an error look like a move, right? But if you're not good at that and you don't look comfortable when you fall out of something. It's set foul and you can see the errors being made.

• 8:20Neil deGrasse Tyson?

  Somebody had to decide one day, you know, I don't want to dance on my feet.

• 8:28Neil deGrasse Tyson?

  Whose idea was it to dance on your head?

• 8:31Speaker 03

  B-boys.

• 8:33Neil deGrasse Tyson?

  This can't be, this was not anybody's mama said that, okay?

• 8:36Speaker 03

  No, no. I mean, it was just B-boys and then a lot of them from, from the Bronx, from New York. I mean, I mean, for example, we take the hespin. The continuous hespin was innovated by a guy named Kit Freeze. And to think of a continuous hespin without your hands just floating and just spinning for as long as you can. That idea is just incredible and to have been somebody that innovated that, I can only imagine their. His thought process must have been crazy for the time to be able to not see that and then just one day just start doing it.

• 9:09Chuck Nice?

  I kind of think of it like the balance beam in gymnastics. When you look at the old balance beam routines in gymnastics. It literally was about keeping your balance. It, it like there were no flips.

• 9:23Neil deGrasse Tyson?

  Can you not fall off?

• 9:24Chuck Nice?

  Yeah, can you not fall off? And then as you watch the progression, it's like, all right, well, you know what I'm gonna do? I'm gonna spin on this little piece of wood. And then somebody was like, oh, okay, you're gonna spin? I'm gonna jump and spin on this little piece of wood. And then it's like, you know what? I want to do a cartwheel on this little piece of wood. You know what? I'm gonna do a backflip on this little piece of wood. And then before you know it, when you look at the balance beam today. It's like these incredible physical feats that these uh women are doing.

• 9:53Neil deGrasse Tyson?

  Chuck, you just invented a new Olympic sport, breakdance balance beam.

• 9:59Speaker 03

  There we go.

• 10:00Neil deGrasse Tyson?

  Yo, that would be so dope. Break Bad Stella. So Rox, I come to this sort of from the point of view of physics. In any physics class, in the first couple of months, you learn all about momentum, linear momentum, angular momentum. You learn about energy and these are sort of the entry level ideas that infuse so much of what we understand the physics of the universe to be. So when you go into these moves, you've got to start out, especially when you spin, you got to start out with a certain sort of beginning angular momentum. Right. So that you can keep spinning once you go into that move. So how much thought goes in to your body parts

• 10:45Neil deGrasse Tyson?

  in advance of a move that is the real money move that you're trying to display?

• 10:51Speaker 03

  Yeah, I mean, for some moves, you really have to already know how to do it as you practice it. So when you're going into it, you really have to have already a center of gravity where you feel you feel very well balanced. Say like a move where your feet don't touch the ground, right? We'll take the head spin for example. I'm going to go into a head spin, keeping my core in and my center of gravity low to the ground. So I'm not throwing myself off balance. So I can go straight into it from one, one throw and just spin for as long as I want.

• 11:16Neil deGrasse Tyson?

  Got it, got it. And also it seems to me, we know in sports, especially in football, when you rotate the football, it spins stabilized. So we do this with, with spacecraft, for example, and some satellites. You spin, we have gyros in there. So is it correct that if you stop spinning, it's harder to stay balanced on the top of your head? So the spinning actually improves while it's acrobatic. In fact, you kind of need to do that to keep your balance. Is that true?

• 11:48Speaker 03

  Uh, you'd be surprised. Some guys can actually just stop on the head with no hands and just from spin.

• 11:53Neil deGrasse Tyson?

  Oh man, that's insane.

• 11:55Speaker 03

  A few people do it, but we actually have what we call a freeze. So freeze is the sudden stop of momentum. So when you're completely spinning at full speed and I don't know where to stop, that's a freeze. The amount of energy that goes into stopping your body from full speed.

• 12:08Neil deGrasse Tyson?

  That's a lot. That's gotta be a lot.

• 12:10Speaker 03

  Yeah, and just sometimes you do it one hand, you do it on two hands, you can stop on your head, you can go to your elbow, you can catch it in a position where your elbow's on your rib and you're, you're just stuck there. And to see those type of-

• 12:21Neil deGrasse Tyson?

  Like you're posing, like you're posing. I've seen that. Yeah, man, that's, that's, that's- It's very cool. So it means you're in full control of all your body parts and all the motion of your body. By the way, there's something called the law of conservation of momentum, linear and angular momentum. So there you are spinning, and then for you to instantly stop, that momentum has to go somewhere. So you can only stop if you brace yourself against the earth.

• 12:47Speaker 03

  Yeah.

• 12:47Neil deGrasse Tyson?

  And so what then happens is you transfer your angular momentum back to the earth. The earth doesn't care.

• 12:55Neil deGrasse Tyson?

  Earth eats it and it absorbs it, but it's still in there in the tiny little bit. So this is you interacting back and forth with the earth, first to give you the spin to begin with, and to have the earth take the spin away, once you're done. But, but there are other ways, like what skaters do. Ice skaters, they'll start with their arms extended, and then they're spinning at a given rate, and we did a whole show on this. Who was our ice skater? Sasha Cohen.

• 13:23Speaker 03

  Sasha Cohen.

• 13:24Neil deGrasse Tyson?

  Sasha Cohen, right. Thank you for reminding me. But we did that on stage in front of a live audience. So if your arms are outstretched and you start spinning, you'll go whatever rate, and then as you bring your arms in, naturally you will spin up.

• 13:37Speaker 03

  Yeah.

• 13:38Neil deGrasse Tyson?

  Now, I don't know that I've seen break dancers do that consciously. How much have you thought about bringing your, your body parts in close to your rotation, the way skaters do, to speed up or then to slow down?

• 13:51Speaker 03

  We do that for sure. It's called the drill. Uh, so when you're doing, for example, you take a head spin and you're open, so your body's open, and then as you lock in, the spin starts to speed up faster and faster, and you end up blocking like a pencil drill.

• 14:04Neil deGrasse Tyson?

  The skinnier you are, the faster you'll spin, yes.

• 14:07Speaker 03

  That's, that's what we call a drill, and then for other type of spin moves that we utilize that have a similar sort of spin and speed is what we call 1990s when you're spinning on one hand, and your body's locked in a, in a pencil position and you're just drilling.

• 14:20Neil deGrasse Tyson?

  Wow.

• 14:21Gary O'Reilly?

  Let me take you back to something you said earlier on. You don't know what music the DJ is gonna play. So that means you're freestyling. How are you? And how quickly are you adapting your shapes, your flares? And keeping them on beat? Because if I wasn't amazed beforehand, once I heard that, I am off the chart, because that's ridiculous.

• 14:43Speaker 03

  Yeah, yeah, so I mean, it's just knowing the rhythm, so. When you hear the song before you go out, usually the musical star in just to stand up where each dancer is waiting to go out. Usually at that time, the dancers are listening to the rhythm of the song and figuring out the the the counts, if they're counting or they're following a certain drum or a certain instrument in the song that they wanna interpret and they wanna highlight for you when they go out. So once they figure out who goes first, then they just keep adapting to the sound. And I mean, the ones that are choreographing the rounds or they have their steps from beginning to end. For them, it's just more like them following the counts and rhythm that they have built in the round. Whereas somebody that's freestyling and adapting, they're gonna highlight different parts of the song that somebody that's watching and listening to the music.

• 15:28Speaker 03

  They're gonna start to see the song more, so they're visually showing you the music with some of the concepts.

• 15:34Gary O'Reilly?

  So this is character interpretation? So you as your individual character through the music?

• 15:40Speaker 03

  Yeah.

• 15:40Gary O'Reilly?

  Fantastic.

• 15:42Neil deGrasse Tyson?

  So Rox, tell tell us about friction.

• 15:48Neil deGrasse Tyson?

  And if you're spinning, you're two surfaces in contact with each other. One is the top of your head. The other is whatever the surface may be. And that surface is not Teflon. It's, well, first, what is that surface in the Olympics? And I've seen kids spin on their head on the cement sidewalks in the city. They're all, they all have male pattern baldness. Well, that's what I'm asking. You're wearing a Red Bull hat, are you just completely bald right on the top of your head? Well, man's got a healthy head, a good thing.

• 16:23Speaker 03

  They're blessed.

• 16:26Speaker 03

  Nah, yeah. I mean, when you're spinning, you feel it. I mean, say I practice, for example, uh, certain moves that I like, like an elbow spin. So I spin on the, on my arm, actually, but.

• 16:36Chuck Nice?

  Don't you say that. Don't. It hurts for you to say that.

• 16:40Speaker 03

  I spin too much. Uh, if I don't have something on, you're callous, or you'll burn your hair off from here. Uh, so when you do head spins or anything related to that, you always wanna have some sort of protection, whether it's a beanie, some sort of rag, or then we'll have a spin cap where it has a material for you to help you spin. Because yeah, floors, it can vary. You can have marly, you can have masonite, you can have a nice wood gym floor or over polished. Gym floor where the skin is just burning every time you slide. So you have to be, you have to be careful.

• 17:11Chuck Nice?

  Now, back in the day, they used to take their hat off. Like, if you wanna spin on your hand, I don't know what it's called, you put your hand down flat, and then your elbow gets tucked in under your torso, and then you use that as kind of like a spindle, and you just keep spinning around on it.

• 17:27Neil deGrasse Tyson?

  It's a springing action, right?

• 17:29Chuck Nice?

  Yeah. And back in the day, they would take their hat off their head and put it on their hand and then use that to spin.

• 17:33Speaker 03

  Yeah, that's a hang glider or a hand spin. So we still use that today, uh, but you can't take your hat off, cause then you have to deal with the hat after you finish your spin. So now what people do, they'll put the sleeve on their hand as they're dancing, so it doesn't take away, it doesn't distract as you're watching it. Because if you see me take my hat off, there's a process of taking the hat off, put it in my hand, spinning, then I have to get out of the hand spin.

• 17:55Neil deGrasse Tyson?

  And that's a whip move, too. Yeah.

• 17:57Speaker 03

  You spin here and just.

• 17:58Chuck Nice?

  Scissor.

• 17:59Speaker 03

  Have people do it barehanded.

• 18:01Chuck Nice?

  Hell, wow.

• 18:03Neil deGrasse Tyson?

  Oh, and, and also, I've seen in many moves, again, this is from, from, I guess, decades ago, uh, you're not so much spinning, it looks like you're spinning, but you're actually sort of rolling around on the ground. Right, so that's a windmill. It's a, it's a, you, you are rolling in contact with the ground. So there's still very good movement, but it's not pure spin on it at a stationary spot. What do you, what do you call that category of moves?

• 18:32Speaker 03

  They're called power moves. Anything related to a spin, uh, where you define gravity, your feet are off the ground. It looks like you're hovering. We consider a lot of those power moves. Um, unless you're doing freezes, where you're doing sudden stops and you're combining that, then that's considered, we call that stacking. The power moves are basically what you're mentioning right now. So a windmill would be considered a power move. And that's one of the first power moves that was utilized in breaking that really helped innovate the dance to where it got to in terms of the dynamic side of it.

• 19:01Neil deGrasse Tyson?

  And another quick thing before we end up with Gary's question, I happen to know in gymnastics, the best gymnasts do not tend to be big people. They tend to be smaller, both men and women. Because I guess your body can tuck faster, you, there's, the distance you have to maneuver to get your body to do something is much smaller. So i- in breaking, is that also true? Are there any big, like, how tall are you, for example?

• 19:29Speaker 03

  I'm, I'm five five.

• 19:31Neil deGrasse Tyson?

  Okay, so that's, that's like right in there, like a gymnast, male gymnast are easily five, five to five, seven tops, right?

• 19:39Chuck Nice?

  Do you see any LeBron James types out there, out there breaking?

• 19:44Speaker 03

  No, I did not. There is a few, but the one thing I will say, there's some guys that are maybe five eight, five nine, five ten that can actually break really well. And when they dance, they just, they stand out way more because their movements are so exaggerated. The way that they attack and the way they connect is really something special to see. Because it's not so common. Usually we're all five, five, five, six, within the same height, but when you see somebody taller come in and if they can dance and have a really fresh style with the music and be able to mix all the dynamics that the dance has to offer. It's really hard to beat people like that because they just, they know how to control the floor more.

• 20:20Neil deGrasse Tyson?

  Let's get to the Olympics, Paris. 2024.

• 20:24Gary O'Reilly?

  People watching the Olympics and watching breaking would not possibly have no exposure to it. Maybe have seen it briefly on TV or something. So what the whole thing, what can we expect, what will happen, etc.

• 20:36Speaker 03

  Well, you're gonna see basically a completely different art form than anybody has seen compared to what we saw in the 80s. I mean, we've been competing steadily since like early 90s when competition really started to emerge on a yearly basis. The dance has evolved so much, you have so many different styles in breaking now, it's not just what we saw back in the day. I think people are really gonna be blown away by the moves that people do, the concepts, the way they connect with the music. Just the styles that you will see on stage, you will see a good diversity. And I'm just really excited for the world to see the new story of breaking and not what it was and what inspired the world. But it's what has gone now worldwide.

• 21:14Neil deGrasse Tyson?

  All right, well, we're gonna look for this, Rox. Thanks for your time to spend with us. And we'll be cheering you on. And maybe we can follow up, you know, after the Olympics.

• 21:24Gary O'Reilly?

  Well, let's find out first if Rox is competing.

• 21:27Neil deGrasse Tyson?

  Oh, yeah, are you competing?

• 21:28Speaker 03

  No, I'm not competing.

• 21:30Gary O'Reilly?

  Oh. But he's invested in mentoring and coaching. So in spirit and soul, he's gonna be there through people that he works with, but possibly not himself busting any moves.

• 21:41Speaker 03

  Yeah, I've worked with a lot of people that are in the process, a few of the ones that are already in it, I've worked with as well.

• 21:48Neil deGrasse Tyson?

  Okay.

• 21:48Speaker 03

  Sweet.

• 21:49Neil deGrasse Tyson?

  All right, so your influence will be felt.

• 21:50Speaker 03

  Yeah. I hope so.

• 21:52Neil deGrasse Tyson?

  All right, Rox, we gotta, we gotta end it there, but thanks for just for being a good sport and for cluing us in to the future. The future of hip hop battle on the world stage.

• 22:04Speaker 03

  Yes, thank you. Thanks for having me. It's a pleasure.

• 22:07Neil deGrasse Tyson?

  Where no one gets hurt unless you hurt your own damn self.

• 22:10Speaker 03

  Exactly, exactly.

• 22:23Speaker 04

  I'm Kais from Bangladesh and I support StarTalk on Patreon. This is StarTalk with Neil Degras Tyson.

• 22:37Neil deGrasse Tyson?

  We have with us Nikita Ducarroz. Nikita, welcome to StarTalk.

• 22:41Speaker 05

  Thank you. Thanks so much for having me.

• 22:43Neil deGrasse Tyson?

  Yeah, so you're freestyle BMX racer in the park discipline, park discipline. A bronze medalist in the 2021 Tokyo Olympics, if I remember correctly. That was delayed from 2020, obviously due to COVID. And a silver medalist in, I got your whole resume here, UCI BMX World Championships 2021 and 2022. European Champion 2021. And so, oh my gosh, we got the right person here to talk about this. So I want to talk about the bicycle, the course design. I don't want to talk about all the physics that might be flowing in and through it. So Nikita, explain, just so we're on the same page. Explain BMX. What does the B, M, and the X stand for?

• 23:27Neil deGrasse Tyson?

  Explain freestyle and explain what park means.

• 23:30Speaker 05

  Okay, so BMX stands for Bicycle Motocross. And that originated more with like the racing side when, as you said before, like they kind of started imitating motocross races on bikes. And then, you know, that evolved into different areas and disciplines. And so now BMX Freestyle Park is essentially same like small bikes, but riding it in skate parks or, um, which could be cement or wood, different materials. But it's basically just doing tricks on ramps on small bikes.

• 24:07Neil deGrasse Tyson?

  Like flips and things and twists and all the kinds of something we can imagine?

• 24:10Speaker 05

  Yep.

• 24:11Neil deGrasse Tyson?

  And one of the surfaces you do this on is cement. I just wanted, I heard that correctly.

• 24:16Speaker 05

  Yes, that's, I mean, that's kind of, I think, what it originated with.

• 24:19Neil deGrasse Tyson?

  Right. Okay, and, and tell me about the design of the bicycle. Because I'm guessing originally, if you're just trying to imitate the motorcycle, you're gonna get a regular bicycle and try those tricks. But over the years, it looks like the bicycle for your sport has changed. And I have to presume some engineers got behind it and say, if we make this shorter or this longer, you can do more flips or be more acrobatic, will give you more balance. So what do you know, at least in your lifetime, that is infused into the design?

• 24:52Speaker 05

  Yes, I mean, there's so many different specs in the bike, all the geometry, everything that you can get into. And like some of it's personal preference, but of course, you know, every little change of degree or size, like you said, affects how you can, what you can do with the bike, if it's easier or harder. So these days now with the park bikes, um, they tend to be a lot shorter. Um, the back end will be a lot shorter because that makes, you know, rotation spins a lot easier versus like a race bike, for example, where they're trying to go fast. They're not really doing jumps like crazy and they manual a lot,

• 25:33Speaker 05

  which is basically like a wheelie without pedaling, just bouncing on the back wheel. So they have a longer back end on their bike because it's a lot more stable.

• 25:42Neil deGrasse Tyson?

  Okay, so the bikes are tuned for the, for your actions and your activity?

• 25:46Speaker 05

  Yes.

• 25:46Neil deGrasse Tyson?

  Interesting.

• 25:47Speaker 05

  Exactly. I feel like it, it really comes down to the bikes because in BMX, even just in like specific discipline that I do, you will find every single body shape, tall, short, bigger, smaller, like, and it all seems to work. So I think it really kind of comes down to the bike itself and how we run them.

• 26:09Gary O'Reilly?

  When you see a course for the first time? Do you immediately know which tricks you're gonna bring forward? Or do you have to, do you get a chance to ride that, feel it, and you know, let it speak to you?

• 26:22Speaker 05

  It's a bit of a combination, like, a lot of times we'll get the image layout of a course, and you could start to think about, it would be cool to do this here and this there. But when you get to a course, it's always so different. Because from a picture, you could never tell the distance between the ramps. You can't feel how steep, steep the ramps are. Um, what the, what the transition, what the radiuses are like. And all of that really affects how ea- easy or hard it is to do certain tricks. Uh, and so until you actually get on the course and feel everything, you can't like exactly set your routine.

• 27:01Neil deGrasse Tyson?

  So in the Olympics, how, how much time do you get to practice on the course that you've never seen before?

• 27:06Speaker 05

  We're never really sure. Uh, last Olympics, we did get a decent amount of time. Like, we had a couple of days in a row, maybe like an hour practice. Because a lot of events, we don't get a lot of practice, like actual on-course time. Um, which makes it kinda hard. Yeah, it makes it pretty difficult. Um, so, but the Olympics, last time around, at least, we're like, generally go about giving us a lot of time to figure things out. Um, cause yeah, I think it, it is a, a, a sport where it's like, for example, I might know how to do a backflip, just to keep things simple.

• 27:39Neil deGrasse Tyson?

  Simple, backflip, simple.

• 27:42Gary O'Reilly?

  How, how casual was that?

• 27:44Neil deGrasse Tyson?

  Yeah.

• 27:47Neil deGrasse Tyson?

  Okay.

• 27:48Speaker 05

  You start getting into all these crazy combinations. But like, doing a trick on one ramp is gonna feel completely different when you move to a different ramp that has a different radius on it. Because all of a sudden, the way you pop off, the speed at which you rotate, everything changes. And so you really have to like, have time on that new ramp to figure out the little tweaks you have to make.

• 28:13Gary O'Reilly?

  Wow.

• 28:13Neil deGrasse Tyson?

  Yeah.

• 28:14Gary O'Reilly?

  Are the surfaces only concrete?

• 28:16Speaker 05

  For most of our competitions these days, it's not wood.

• 28:19Neil deGrasse Tyson?

  So, since wood has a certain give to it, that's, that concrete doesn't. If you have energy landing on the wood, some of that energy will come back to you in ways that would not have from the concrete, so.

• 28:33Speaker 05

  The courses that they build for events are usually temporary courses. So they, you know, they'll put up like a scaffolding. Base and then build the course on top. And so because of that, it's not, you know, a permanent structure. There is a lot more flex. Everything feels softer. So your speed isn't going to be as much. You're gonna have to really, depending on the course, either pedal a lot more or pump a lot more to get the speed because yeah, everything's kind of soft compared to, even compared to a wood park that's like more permanent, a permanent structure, or it's on top of a concrete base.

• 29:09Neil deGrasse Tyson?

  Okay, so you're saying something beyond what I said, because what you're saying is, because of that give, the wood is actually absorbing energy from you, and you have to compensate by pedaling a little harder or pushing off the turn a little harder.

• 29:22Chuck Nice?

  It's like a box spring in a mattress. The base that you put it on, like if you have a really nice firm base, then you're gonna get more return from the wood course.

• 29:32Neil deGrasse Tyson?

  If it's squishy, it'll just absorb it out. Yeah. Okay. Gary, what other questions you have?

• 29:37Gary O'Reilly?

  What happens if the ramps are so high? How do you then deal with that? Is it, is it advantageous to you and your routine? Or is that just, you've got to change your whole thing because the ramps are higher? Does that work?

• 29:50Neil deGrasse Tyson?

  In fact, don't you want high ramps? Because then you have, if you come off of it, you have more time to, and distance to do your flips and gymnastics?

• 29:58Speaker 05

  So it would depend because you could have a high ramp that has a mellor transition, or you could have a high ramp that has a steeper transition, or vice versa, a shorter ramp with a steeper one. So I think it's less about the height. Like, we typically ride a lot bigger ramps at competitions, and I think they have gotten bigger over time, and we don't notice it too much because it's been so gradual. But I think it's a lot more about the radius of the takeoff that, that affects things. Because a steep, obviously a steeper radius will send you straight up, which gives you more time for tricks, but also you will have to push through it a bit to make it over versus just getting

• 30:43Speaker 05

  shot straight up and coming back down and like not making it to the landing.

• 30:48Chuck Nice?

  You don't, you don't want to come back down where you started.

• 30:50Speaker 05

  No.

• 30:51Neil deGrasse Tyson?

  You need some forward motion there. Yeah.

• 30:53Speaker 05

  Exactly. And then like a, like a mellor landing, or a mellor takeoff, sorry, is obviously easier to get over the jump, but you're gonna stay lower to the ground. So you won't have as much time for tricks. So there's really like a, a sweet spot.

• 31:08Gary O'Reilly?

  You said you don't get much access pre-competition to the park course. But what happens when you come across a fast one? Does that allow you to go max on the tricks? Or is it like, you know what, I really have to control this better?

• 31:21Speaker 05

  Because our courses are just flat, like it's not downhill or anything. We're not going in a, in a straight line down a set course trail or whatever. You know, we just have like a square or rectangle, tangled surface with different ramps and you can go wherever you want.

• 31:38Neil deGrasse Tyson?

  Just to be clear, unlike snowboarding and unlike skiing, in your sport, you are pumping energy into what you're doing at all times.

• 31:49Speaker 05

  Yeah.

• 31:49Neil deGrasse Tyson?

  So you can go against gravity in ways that other people cannot really do so. The gravity vector does not stop what she does because she can pedal against gravity. But you can't just on a ski slope turn around and say, I'm going to ski up slope and do half of this course again.

• 32:07Gary O'Reilly?

  You can if you're a peek-a-boo street.

• 32:09Neil deGrasse Tyson?

  Never mind. Sorry. I'm sorry.

• 32:11Speaker 05

  Well, yeah, so we, we're kind of using the transitions again. Everything's about like pumping down the transitions and up to kind of maintain your speed. So when you go up and you do a trick, you want to land really nicely in that transition and you pump out of it to really get the max speed for the next thing. And you can throw pedals in, you know, here and there as needed. But yeah, faster rolling course, which would be a course that maybe is a little more solid on the ground or there's more space in between the ramps. That just helps you to, I guess, not have to work as hard to like get over thing, to jump over. Cause you don't, you, you won't have to pedal as much. You'll be able to just use the momentum from the ramps to go to the next one.

• 32:57Chuck Nice?

  What, what's more valuable when they're, when they're judging you? Cause like some of the tricks, there's a lot of stopping. Like you'll see, they'll come to the top of the ramp, they'll come out of it, they'll land on the back tire all by itself. Take a hop, turn around, go back down. Or they'll do the same thing on the front tire and stop. And then there's other tricks where they come out of the ramp and they'll like do something crazy like just spin the whole bike around and go right back into the ramp. Well, how, how do judges determine what is more valuable to judge?

• 33:33Speaker 05

  I mean, I think with freestyle BMX, it's always been a bit difficult because it is kind of biased. Like, there's no set points for specific tricks or whatever. So now, like, the first thing you said about, you know, like, bouncing on the wheel. I think that's kind of phasing out a bit from the park competition specifically. You'll see that maybe in other disciplines.

• 33:53Neil deGrasse Tyson?

  Chuck, that's old school.

• 33:55Speaker 05

  Old school, yeah. So now, now it is a lot more just like going out of the ramp and doing some crazy spinning things.

• 34:03Neil deGrasse Tyson?

  So the Olympic motto will have to be amended. So faster, higher, stronger, cooler, like, cool.

• 34:12Gary O'Reilly?

  Now, you, you, you stood on the podium last time in Tokyo. I guess the itch is there to be scratched. You want to be gold. What's it gonna take?

• 34:21Speaker 05

  Man, it's gonna take a lot. There's, since the last Olympics, uh, to the next one, there's been a surge of young women joining the sport, which is super awesome because women's BMX was really slow for such a long time and we've had just this massive explosion. And with that, the tricks are getting crazier and crazier. I'm now considered like one of the old dogs, which is crazy. Um, I wasn't ready for that, but like, we're competing now with kids that are like 16.

• 34:52Neil deGrasse Tyson?

  Wait, so, so wait, have you been, have you been mammed yet by one of the younger?

• 34:56Speaker 05

  I haven't.

• 34:59Speaker 05

  I don't want that to happen.

• 35:02Speaker 05

  I haven't been mammed yet, thank God.

• 35:04Neil deGrasse Tyson?

  Yeah, I haven't been mammed yet. That's, I'm told that's a day, that's a day.

• 35:08Speaker 05

  That's, yeah. I might like go home and cry if that happens, but.

• 35:13Speaker 05

  But yeah, it's just gonna take a lot of training. Um, new tricks are really gonna be necessary this time around because every, every girl out there is really pushing the tricks, like tricks that. Women haven't done in competition yet. The judges really do appreciate like an overall solid run where you're hitting kind of all the criteria like use of course, the heights, the flow, and obviously like the tricks and like I said, new tricks because there are also judges that have seen us ride in the past. So there is going to always be that bias. And if you bring something new to them and something new to the crowd, you know, the crowd will go crazy. And I think that kind of affects things as well. So a lot of work.

• 35:54Neil deGrasse Tyson?

  So Nikita, it's been a delight to have you on StarTalk special edition. In our third and final segment, we're going to bring back our geek in chief, Charles Liu, up next on StarTalk.

• 36:24Neil deGrasse Tyson?

  All right. So we got to make sense out of all of this. And you know who I I've reached for when I want to make extra sense. I can make some sense, but to make real sense out of the physics of the universe, we bring in StarTalk's geek in chief, Charles Liu. Charles, welcome back.

• 36:39Charles Liu?

  Hey, great to see you, everybody. Neil, Chuck, Gary, you guys are awesome. These two athletes are amazing, Nikita and Rocks. I mean, I love it. And the physics, gotta say, is amazing, too. Can't wait to talk about it with you all.

• 36:55Neil deGrasse Tyson?

  Oh, let's do it. So there's things that are rotating, if not the body, then wheels. In addition to the wheels rotating, the the handlebars, the stuff. So where do we wish we start here?

• 37:07Chuck Nice?

  What's your spin on this, Charles? Oh.

• 37:13Chuck Nice?

  We went there so soon. I you know what? And I I'm so ashamed.

• 37:17Neil deGrasse Tyson?

  Now you got no joke left.

• 37:18Charles Liu?

  The world has turned.

• 37:19Chuck Nice?

  I'm so ashamed.

• 37:20Charles Liu?

  Oh, my gosh.

• 37:21Chuck Nice?

  Go ahead.

• 37:21Charles Liu?

  Uh, listen, these two sports are fundamentally about rigid body rotation. When you have things that are spinning around other things, systems of rotation, really, right? The human body, you think of, say, you're doing a head spin, or Rocks is doing a head spin, for example, you have your foot hinged to your leg, hinged to your hip, hinged to your torso, hinged to your arms, hinged to your head. And every one of those has got its own rotational thing going on. Hmm.

• 37:52Neil deGrasse Tyson?

  Charles, I have to clarify, you said rigid body rotation?

• 37:56Charles Liu?

  Yeah.

• 37:56Neil deGrasse Tyson?

  Some people are less rigid than others.

• 37:59Charles Liu?

  Oh, yes.

• 38:00Chuck Nice?

  When I turn over on the couch, is that rigid body?

• 38:04Charles Liu?

  Surprisingly, perhaps, yes. But it's not that your whole body is rigid, it's that you have numerous pieces that are rigid that are attached to things and together they create this net effect of rotation and motion, right? Now, in physics, the amount of motion we use loosely could be referred to as momentum, right?

• 38:26Neil deGrasse Tyson?

  That's a term we're all familiar with, even if we don't know it mathematically, we have an intuitive sense of momentum.

• 38:32Charles Liu?

  Sort of the amount of motion you have. Now, the amount of rotation you have, we kind of call angular momentum. And in the same way that force is a change in ordinary momentum, torque, like the thing you do on a wrench, right, is the analog when you change rotation.

• 38:52Neil deGrasse Tyson?

  So why don't they call it angular force?

• 38:54Charles Liu?

  They could. It wound up being called torque for some historical reason, which I do not know.

• 38:59Chuck Nice?

  Torque sounds, sounds much more cool and, you know, I gotta say, it's more superhero.

• 39:05Gary O'Reilly?

  It is, it's a superhero name.

• 39:07Chuck Nice?

  It's more superhero, like, you know what I mean?

• 39:09Charles Liu?

  Yeah, well, supervillain, perhaps. I shall torque you, ha ha, Spider-Man, you know, that kind of thing.

• 39:15Gary O'Reilly?

  There you go.

• 39:16Charles Liu?

  Torque is a French word. I wonder if it was developed after the Newtonian history. I don't know, Neil, you know much more about this.

• 39:23Neil deGrasse Tyson?

  It had to, the angular stuff all came after the linear stuff.

• 39:25Charles Liu?

  Right, right, so maybe Lagrange or Legendre had something to do with it. Well, Gary, you know much better than we do, as an athlete, you're always thinking where your joints are, where your arms are, your legs are, your head is, in relation to what you're about to do with the ball.

• 39:42Gary O'Reilly?

  You're always setting yourself up. For the next event that you're going to execute, whether it be on a bike or whether it be in your choreography. What I found really fascinating when we spoke to Rocks was they don't know which piece of music's coming up. Yes. It's not as if it's, you know, like ice skating where they know it's Revell's Bolero and they're going to do set certain moves all in a stream. These guys are feeling it.

• 40:09Charles Liu?

  There's a certain amount of improvisation.

• 40:11Gary O'Reilly?

  Totally. So intuitive and they've got to feel what move is about to go down correlates with the music. Once the music starts, they might know this piece of music, in which case they can drop a certain move in at a certain time. Right. They've got to get there. That was, that's the sort of intuitive athletic ability.

• 40:31Chuck Nice?

  That's why if I was the DJ, I would play a waltz.

• 40:34Charles Liu?

  Oh, breaking to three quarters time, I would love to see that.

• 40:43Charles Liu?

  But never mind you that, right? Gary, you hit the nail on the head.

• 40:46Chuck Nice?

  Yeah.

• 40:47Charles Liu?

  When we are talking about torque, what's really cool is you can generate a tremendous amount of torque with only a little bit of force.

• 40:56Chuck Nice?

  And how so?

• 40:57Charles Liu?

  Well, it has to do with the lever arm.

• 41:00Chuck Nice?

  Aha.

• 41:01Charles Liu?

  Right? What we call sometimes a lever arm, think about when you're trying to stop a door from slamming.

• 41:07Chuck Nice?

  Right.

• 41:07Charles Liu?

  If you put a little tiny bit of energy near the doorknob, a little bit of force will stop the door. But if you're near the hinge, you have to push a lot harder to keep that door from slamming.

• 41:17Chuck Nice?

  All right.

• 41:17Charles Liu?

  So by the same token, depending on whether it's your fingertips or your wrists or your elbows or your toes or whatever, you can exchange a tiny bit of force and put it into the system and bingo, you get a big effect. This is what Archimedes was referencing. When he said, Chuck, you got to, you surely know this quote. Give me a long enough lever and I shall move the world.

• 41:43Chuck Nice?

  Oh, I thought it was give me a long enough lever and I will bust a move.

• 41:50Charles Liu?

  Archimedes in the toga, right? Dancing the waltz.

• 41:54Neil deGrasse Tyson?

  No, no, that's Archimedes in the hood.

• 41:59Charles Liu?

  My goodness.

• 42:00Neil deGrasse Tyson?

  Wait, wait, I thought it was Charles instead. Give me a place to stand and I can move the world.

• 42:04Charles Liu?

  Yes, that's, that might be even more accurate. After the show, I'll call him. Yeah. We'll find out exactly what he said, yeah.

• 42:10Neil deGrasse Tyson?

  So he knew that with a long enough lever arm, even someone with the meager strength of a mere human, the torque can very much work in your favor, provided, you know, the physics as he certainly did.

• 42:21Charles Liu?

  That's right.

• 42:22Neil deGrasse Tyson?

  Okay.

• 42:22Charles Liu?

  So with the bikes.

• 42:24Chuck Nice?

  Oh, wait a minute. And so when you're talking about levers and you have the point where the lever is the fulcrum, whatever, is it always you have to have the shorter side, which is doing the work? And the longer side is where you're pulling? Like you can't have them be equal, right? You don't get torque that way, do you?

• 42:40Charles Liu?

  You do.

• 42:40Chuck Nice?

  I'm asking.

• 42:41Charles Liu?

  Great question. There are three different kinds of levers.

• 42:44Chuck Nice?

  Okay.

• 42:44Charles Liu?

  Okay. And in fact, each one of them is useful in a different way. So one kind where Archimedes is moving the world, you're way longer on your side of the fulcrum than the other.

• 42:55Chuck Nice?

  Okay.

• 42:56Charles Liu?

  When you have something equal, uh, that'd be like a pair of scissors, right? You don't need that much force, but you're pushing two wedges together, thus creating a cutting motion. If it's too long, then you don't gain any advantage.

• 43:08Chuck Nice?

  Got you.

• 43:09Charles Liu?

  Now then, the third kind of lever, which is super cool, right? Is where you actually have the fulcrum closer to you than to what you're doing. That's when you actually produce more force, but you want to spread it out more. An example is like a broom. If you want to sweep something, say a whole bunch of dust off of the ground, you don't need a lot of force, but you need area. So you use the lever in such a way, the broom, where the fulcrum is, you're holding it up in the corner.

• 43:38Chuck Nice?

  Right. The pushing starts way up top.

• 43:40Neil deGrasse Tyson?

  Right. Nobody brooms with their hand down near the sweeper because then you don't get any, any motion.

• 43:45Charles Liu?

  You don't get the advantage. So you're literally improving the sweeping effect by having that weird kind of lever that you don't think of when you're trying to move the world.

• 43:53Neil deGrasse Tyson?

  That was Archimedes, the janitor. Right.

• 43:57Gary O'Reilly?

  So Charles, are we looking at multiple axes of rotation here for either of these guys?

• 44:03Charles Liu?

  Absolutely. That's where the beauty and the athleticism come along, right? Nikita was talking about this amazing trick being worked on, right? Where you are backflipping with the bicycle, which is one axis of rotation, and throwing a handlebars, which is the other axis of rotation, at the same time. They actually affect each other in ways that are so complicated that she can't calculate them. She has to try it and try it and try it until it works by falling into the foam pit, right? This is true in our physics as well. As soon as you throw in a second and a third rotational axis, things start getting very complicated. I heard a story once, one of my colleagues, senior colleagues,

• 44:48Charles Liu?

  was working with the Chandra X-ray Observatory. And what he said was, the hardest thing for the flight engineers and the aeronautic engineers to work on is actually measuring things like the roll, pitch, and yaw of the telescope as it's orbiting the Earth while it's orbiting in this highly elliptical orbit, while it's doing this and that and spinning, actually to point it at the place you want it to point for seconds or minutes or hours at a time. And to stay pointed to the thing. That's right. It's very, very complicated. And so, doing it on this human microcosmic scale with no computer other than your brain, you're just simulating, you're redoing, you're practicing over and over again to get these kinds of things lined up.

• 45:33Charles Liu?

  You're literally calculating things like the tennis racket theorem and the moments of inertia in real time. What's the tennis racket theorem? Oh, oh, oh, yes, that's right. We should talk about this. But you can't just drop that on us and walk away. Exactly, yeah. All of you who are interested, go read about moments of inertia, okay? Think about momentum. When you are creating a momentum in physics, it's the mass times your velocity, right? Mass is like the amount of stuff that is moving when you're calculating a momentum. So moment of inertia is the thing that allows you to figure out like the characteristic

• 46:16Charles Liu?

  of your object or your bodily system with many parts that will react to rotation, what we call angular velocity, in the same way. So angular momentum is angular velocity times the moment of inertia. Okay, so that's the technical phrase.

• 46:35Neil deGrasse Tyson?

  But just to clarify, what we're saying here is, we have maths that we have an intuitive understanding of. The mass equivalent in rotation is the moment of inertia.

• 46:46Charles Liu?

  Well said.

• 46:47Neil deGrasse Tyson?

  Okay.

• 46:47Charles Liu?

  That's right. So conversationally speaking, we are always looking at objects with different strange shapes. Okay, they may be oblong, they may be multi-part, things like that. If you can calculate its moment of inertia in the same way that you can weigh an object and figure out its mass, then you will know how it will react, or how that part of your system will react when it gets spun. And, and so the tennis racket theorem is one of four really cool theorems about spinning and moments of inertia. You should try it yourself sometime. Take a tennis racket, and if you try to spin it in three different ways, you throw it up in the air, in one axis, it just comes right back to where it was, no problem.

• 47:31Charles Liu?

  You spin it in another axis, it also comes right back to where it was, no problem.

• 47:36Neil deGrasse Tyson?

  I did this with Chuck.

• 47:37Charles Liu?

  Yes.

• 47:37Neil deGrasse Tyson?

  Chuck, didn't I demonstrate this to you with a book?

• 47:39Charles Liu?

  That's right.

• 47:40Neil deGrasse Tyson?

  I didn't know, I didn't know there's a tennis racket.

• 47:42Charles Liu?

  Well, you could call it the book theorem if you want. It's technically called the intermediate axis theorem. But basically, you spin it in the third direction, in that intermediate direction, and it will always do a flip.

• 47:53Neil deGrasse Tyson?

  Charles, this blew my mind when we first did it in physics class.

• 47:56Charles Liu?

  Yeah.

• 47:56Neil deGrasse Tyson?

  When I was in high school.

• 47:57Charles Liu?

  Yeah, isn't it cool?

• 47:58Neil deGrasse Tyson?

  So let me, let me give a gander at it. So if you have an object that has three different axes of rotation, okay, so let's take a, just take a book, or, or like you said, a tennis racket. I think of books because they're like.

• 48:12Charles Liu?

  They're flat.

• 48:13Neil deGrasse Tyson?

  They're flat, thank you.

• 48:14Charles Liu?

  Each axis has its own moment of inertia.

• 48:16Neil deGrasse Tyson?

  Exactly. So you can spin it horizontally, that's easy.

• 48:19Charles Liu?

  Right.

• 48:20Neil deGrasse Tyson?

  You could spin it vertically, that's easy, but if you want to spin it top to front, that moment of inertia, the value of that moment of inertia is lower than one of the values and higher than the other.

• 48:37Neil deGrasse Tyson?

  And the system is unstable rotating around that axis. And it goes to the other axis all by itself.

• 48:45Charles Liu?

  That's right.

• 48:45Neil deGrasse Tyson?

  It's mind blowing.

• 48:46Chuck Nice?

  So we'll always flip.

• 48:48Charles Liu?

  No, we always flip.

• 48:49Neil deGrasse Tyson?

  Oh, yes. You could, by the way, you could do it with your cellphone, but you might drop it.

• 48:53Charles Liu?

  Yeah.

• 48:53Neil deGrasse Tyson?

  That's what I'm saying.

• 48:53Charles Liu?

  Do it over a foam pit.

• 48:55Neil deGrasse Tyson?

  So, so Charles, we have these athletes. So you're giving me much more appreciation of what they're doing.

• 49:00Charles Liu?

  Yeah.

• 49:00Chuck Nice?

  Yeah.

• 49:00Neil deGrasse Tyson?

  By, in the way you describe it, I'm thinking, what? A sprinter only has to move one leg in front of the other?

• 49:08Charles Liu?

  Kind of. Yeah.

• 49:09Neil deGrasse Tyson?

  Really? Like, that's all Usain Bolt is doing?

• 49:13Charles Liu?

  The athlete is not just doing singular directional motion, but the body as a whole moves in the singular direction. That's the key. When we're judging the BMX or we're judging the braking, you are judging motion in multiple dimensions, which makes it more complicated. In soccer, Gary, the obvious analog about rotating multiple times and trying to get something to move is the bicycle kick.

• 49:40Chuck Nice?

  Yeah.

• 49:40Charles Liu?

  Right. And when every time I see a bicycle kick, I'm, I'm just going, there's some moment of inertia change going on there.

• 49:46Gary O'Reilly?

  When you connect with it and it goes in, that's like the hundredth time you've tried it. Cause generally it's more likely that you miss, but honestly, it's true.

• 49:56Neil deGrasse Tyson?

  Right, Gary, are you speaking for yourself?

• 49:58Gary O'Reilly?

  Of course.

• 49:59Charles Liu?

  Yeah.

• 50:00Neil deGrasse Tyson?

  Have you ever done a bicycle kick, Gary?

• 50:02Gary O'Reilly?

  Yeah, yeah. So, and, and I've connected, but the thing is, you, hi, even a blind dog can find it both.

• 50:08Neil deGrasse Tyson?

  Wait, wait, Gary, is there video of you connecting?

• 50:10Gary O'Reilly?

  Of course not, no.

• 50:11Charles Liu?

  Oh, man.

• 50:14Chuck Nice?

  Well, in that case, I remember when I did a bicycle.

• 50:17Gary O'Reilly?

  Exactly.

• 50:20Gary O'Reilly?

  When we talk about muscle memory in athletes, right? And you practice, you practice, you practice, your memory has another neurological imprint. Where imagine Nikita's doing her double axis flip and all the rest of it. To be able to practice knowing where her head should be, knowing everything in the landscape around us, and learning and learning and learning, just like you would strengthen muscles to achieve certain, certain performances.

• 50:45Charles Liu?

  That's right.

• 50:46Neil deGrasse Tyson?

  What I want to bring from what Charles said into this is when you do a bicycle kick, not only is your body rotating, but when you are in the proper position.

• 50:57Neil deGrasse Tyson?

  Your leg not only moves forward, you then pivot at your knee. So that you get like three times the extra force on the ball. The rotation of your body, the movement up in your ball joint of your hip. And the movement of your knee joint. Am I right here, Charles? I think I'm right there.

• 51:16Gary O'Reilly?

  It's a series of levers.

• 51:18Charles Liu?

  That's right. Yeah. Each lever adds to the ultimate amount of acceleration you provide to the ball when you strike it. It's amazing.

• 51:27Neil deGrasse Tyson?

  It's so amazing how quickly the ball comes off the foot. In a bicycle, get faster than if you just ran up to the ball and kicked it. Cause you've got all this rotation going behind it.

• 51:36Charles Liu?

  Usually, yes, but it doesn't always have to happen that way, right? It also depends, uh, like Ronaldo had an amazing kick just right off the ground. Right? Because he is tall and lanky and he was able to snap those levers, those pieces of his body in such a way as to provide tremendous energy.

• 51:56Gary O'Reilly?

  You have to make a really clean contact as well on the ball. If you only get a grazing blow on it, then that kind of theory goes away.

• 52:03Neil deGrasse Tyson?

  And then it's embarrassing and you don't make the highlight reel.

• 52:05Gary O'Reilly?

  No, you don't. No ESPN for you.

• 52:08Neil deGrasse Tyson?

  Okay. So, so all their body parts are moving in all different ways that they're in control of. And we watch this in awe.

• 52:19Charles Liu?

  That's right.

• 52:19Neil deGrasse Tyson?

  Again, now I'm not impressed with, with Usain Bolt. You ruined the Olympic.

• 52:25Charles Liu?

  No, no, no, no. Usain is amazing. No, please. But just remember that this is three dimensional motion, right? It's the difference between enjoying watching something linearly and watching something going in all directions. I mean, you were talking about Rox being able to adapt instantaneously to the music that's available. Right? Uh, let's say, let's say Chuck puts on that waltz. Right? And Rox has got to break to the waltz. He already has in his brain, the muscle memory to do certain things in three quarter time. Right? And what do you do to make all those things come together? In the end, it's that beautiful artistry of body parts moving in concert, in sync,

• 53:10Charles Liu?

  together with what you have in your brain, what you've learned to do, what your muscles know how to do instinctively. That creates these amazing routines and amazing athletic activity.

• 53:20Neil deGrasse Tyson?

  Now that you mention this, I think we were, we've been primed. To receive this because of what we've already come to love in gymnastics.

• 53:29Charles Liu?

  Yeah.

• 53:30Neil deGrasse Tyson?

  Bodies twisting, turning, tumbling, the body's doing things more than one thing at a time. And so now you take the time honored uh displays in gymnastics and apply to these two new sports new to the Olympics. And I I now I'm looking forward to it because I was like indifferent at first, but.

• 53:50Charles Liu?

  No, no, no. And and think about skiing aerials or the skateboarding where you're in the pipe and you're doing rotations and moving at the same time. Think about diving where you're being accelerated constantly in one direction while you're twisting your body back and forth and back and forth. It's all there. We just never really think about it that much on the Greek statues, right? They they're only one directional most of the time.

• 54:16Chuck Nice?

  So let me ask you this, what is keeping you from the drift? So what is it about this motion that's keeping you on the line of your gravity? You're just falling straight down, but you don't see the person, they jump off, but they don't keep going to the left, out, out, out into the pool. They go straight down, even though there's twisting and turning and twisting and turning. When they do the same thing in gymnastics, the same thing in breakdancing, what is keeping you in place?

• 54:45Neil deGrasse Tyson?

  Gravity.

• 54:47Charles Liu?

  Your launch.

• 54:48Chuck Nice?

  Gravity.

• 54:49Charles Liu?

  Gravity. Your your initial launch, if if the diver jumps outward too far, they will go in a parabolic.

• 54:58Chuck Nice?

  Okay.

• 54:58Charles Liu?

  The diver must know how to jump pretty much exactly straight up and straight down.

• 55:03Chuck Nice?

  Yeah.

• 55:03Charles Liu?

  Right? Also, if there's a wind, they will drift.

• 55:06Chuck Nice?

  So it's as little lateral movement as possible is what you have to incorporate in order to get.

• 55:12Neil deGrasse Tyson?

  And I'll tell you something else. Unlike golf, we can slice or what's the other one? You slice or.

• 55:17Charles Liu?

  Hook, hook, hook.

• 55:18Neil deGrasse Tyson?

  Or hook. That's because there's a spin on the ball interacting with the air.

• 55:22Charles Liu?

  That's right.

• 55:22Neil deGrasse Tyson?

  Now, the gymnasts are not spinning that fast or moving through the air that fast.

• 55:27Chuck Nice?

  That'd be a ten.

• 55:28Neil deGrasse Tyson?

  They gotta worry worry about a spin deflection through the air.

• 55:32Charles Liu?

  That's right.

• 55:32Chuck Nice?

  That would impress the Russian judges, that's for sure.

• 55:34Neil deGrasse Tyson?

  Finally, I don't think there'll be Russian judges in this.

• 55:37Chuck Nice?

  Oh, that's right. There won't be Russian judges this year.

• 55:39Charles Liu?

  No.

• 55:40Neil deGrasse Tyson?

  So Charles, encapsulate this. What kind of, what's the physics we should pay attention to?

• 55:45Charles Liu?

  When you're looking at the BMX and the breaking sports, look for the combinations that show the most rotation in the most numbers of axes.

• 55:56Neil deGrasse Tyson?

  Ooh.

• 55:57Charles Liu?

  Right. Watch for the breaker's body as they are rotating maybe on their head in this direction clockwise, counterclockwise. Meanwhile, their other parts, their hips, for example, may be rotating in a different angle. And meanwhile, they're doing all these things together. The complexity of what they can do in different axes is what's gonna matter. Similarly, in the BMX, especially in the tricks, see if they are doing the combination of the backflip with some other twist. Are they doing another turn? The complexity, the more you put in, the cooler it is and the physics just pops out in this sort of beautiful display. For BMX, I might be looking for a Swiss gold, okay? Let me just say, I just might.

• 56:41Chuck Nice?

  Oh, look at you!

• 56:42Neil deGrasse Tyson?

  Okay, but, but how about breaking? You know, I'm from the Bronx, you know? You would tell me, like, no.

• 56:48Charles Liu?

  We all must love the art form, but just like you said, Neil, if you're thinking about the culture expanding.

• 56:58Neil deGrasse Tyson?

  Yeah.

• 56:58Charles Liu?

  Wouldn't it be amazing if a Swedish or a French or a Korean athlete won a breaking gold?

• 57:05Chuck Nice?

  No!

• 57:05Charles Liu?

  Right?

• 57:08Chuck Nice?

  The hell you talking about? No, it would not. It'd be good if they won silver, but not gold, no!

• 57:12Charles Liu?

  Okay, silver is fine. Imagine if it's gotten to that point, right? That means that America has overall, once again, been able to influence the world in a positive way.

• 57:26Neil deGrasse Tyson?

  Let me say that another way here. So Chuck, if America loses to a Scandinavian nation?

• 57:32Chuck Nice?

  Right.

• 57:33Neil deGrasse Tyson?

  America still wins because our influence has spread far and wide.

• 57:37Chuck Nice?

  Now, I want a double win. I don't care about none of that. That's Mark, man. Mark, I don't want no doggone, uh, uh, uh, what you call it, uh, uh?

• 57:45Charles Liu?

  A moral victory.

• 57:47Chuck Nice?

  A moral victory, we don't need that.

• 57:48Charles Liu?

  No, no, no.

• 57:49Chuck Nice?

  We're not here to touch the world, we're here to, we're here to win!

• 57:52Neil deGrasse Tyson?

  All right, we got to end it there. Charles, it's a delight always. As always. On these conversations, you ratchet it up with torque to another level every time you participate. Thank you, thank you so much. What a pleasure. And let me just end with a quick cosmic perspective. You know, I'm an Olympics purist. I kind of only want like the sports that ever appeared on the Grecian urns, but I can be warmed to other human exploits. You know, the whole world is not just the javelin and the discus. It's how the inventiveness of people, cultures, places, things come together. And reach for the aspirational goals established by the Olympics faster, higher, stronger.

• 58:37Neil deGrasse Tyson?

  And I've been softened in this conversation and in others I've had. For those who want to see the growth in all the ways people can express their own talents of mind and of body on a world stage. And that's a cosmic perspective. Again, Charles, good to have you. Pleasure. And Gary, Chuck, until next time. Neil deGrasse Tyson, as always, keep picking up.