Things You Thought You Knew – Your Zodiac is Wrong

Star Trek Intro

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Episode Introduction

1:33Hello, StarTalkians. Coming up, we've got another Things You Thought You Knew episode. This time, Chuck and I riff on Einsteinian time dilation, the mysterious gravity assist that space probes get, and the North Star. Spoiler alert, it's not all it's cracked up to be. Coming up on StarTalk.

1:58Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now.

Time Dilation Discussion

2:12I still lose sleep over this fact. Okay. I still lose sleep over it, and I want you to lose sleep, too. I don't want to be the only one staring at the ceiling at night. I've got to tell you, a lot of things already beat you to that. Oh, sure. You mean the asteroid strike that could happen? Yeah, exactly. Or the global warming? Yeah, yeah. So, here it is. You may remember, or you may have heard, that Einstein's relativity, more specifically,

2:44you learn this in Special Theory of Relativity, where the faster you move, the slower time ticks for you as others view it. Relative to the observer. Relative to the observer. Correct. You don't know anything's happening. Right. Your clock still ticks as far, you've still got your heartbeat, all of this. Okay. So, this is not a physiological thing. It's an actual property of the fabric of space and time under those conditions.

3:17Wow. Okay. That is fascinating. It is. It's completely fascinating. It's completely. So, I watch you fly by, and the faster you go, the slower time ticks for you. Okay? But my time stays the same. To you. To me. Right. To you. So, not only does speed do this, also the strength of a gravitational field will have the same effect on you. Oh. The stronger the gravitational field is, the slower time ticks for you. Oh. And that wasn't formulated until his general theory of relativity, 10 years later.

3:50That took a lot more math and deeper insights into the universe. So, once again, it makes sense because you're dealing with the fabric of space-time. It's a fabric of space-time. Correct. Wow. Okay. But initially, when formulated, you're thinking it's just because you're moving. Right.

Gravity Assist Explanation

4:05But it's actually way deeper than that. Yeah. And that's why that one. Oh, by the way, his original special theory of relativity was not called that. The title of the research paper was On the Electrodynamics of Moving Bodies. What? Okay. That was the title. We would later call it the special theory of relativity because it was a special case of what would later then be called the general theory of relativity. Okay. Right. So, the geosynchronous satellites are like middle orbit. That is far enough away from Earth's source of gravity for them to have a difference, a

4:36measurably different space-time condition. Oh. So, that their clocks tick faster than our clocks on Earth's surface because they're farther away. And so, remember I said the more intense the gravitational force, the slower time ticks. So, they're farther away. Their time ticks faster relative to us. But we get precise timings from geosynchronous satellites.

5:06So, how does this work? We pre-correct the time signal from the GPS satellites to compensate for Einstein's general theory of relativity so that by the time the time reaches us, where it's been properly corrected and it matters to us and our space-time continuum, not the one that's in middle Earth orbit. Oh, my goodness. So, GPS couldn't work as accurately as it does. However, wait a minute.

5:36What? I'm sorry. Just for me. You would have to have a standard in order to pre-correct something. You know the rate at which its time is speeding up because you can calculate what the gravitational field is up there. There you go. There you go. Okay. Okay. And once you calculate that, then you do and you say, oh, my gosh, the formula works. Einstein was right. Right. This is not just something on high theory, hypothesized that may or may not be true.

6:09It is true. I just want to be there when that phrase is uttered. Oh, my God. Einstein was right.

6:21Yeah. These aren't just cult heroes that we wish they were right. Right. These are real. This is real. Okay. This is the real universe we're talking about here. Okay. So, now watch. Let's keep going faster and faster. Let's go half the speed of light, three quarters of speed, 90% the speed of light, 99% the speed of light. Time is ticking slower and slower and slower. For you, you will watch the whole future history of the universe unfold in front of your eyes as fractions of a second go by for you.

6:53As you go 99, there's a formula for this, of course, but 99, 99.9, 99.99% the speed of light. Because you're the observer of that. Of that. But for you, your time has slowed to the point where as you observe the things that are not moving at the speed of light, you see them- Speeding up, correct. Basically, you see them unfold. Correct. Boom. God. Correct. That is insane. So, now watch. Oh, my God.

7:24Wait. No watch. Okay. Wow. So, I didn't even get to the part where I lose sleep. Okay. Okay. That's what happens. By the way, by the way, there are particles that decay. You've heard of like radioactivity, right? Yes. Right. One part, it decays and becomes another part. It releases often deadly energy. Yes. Okay. Radioactivity. All right. Some particles. Let's take, for example, the proton or the muon.

7:55One of these decays in like six minutes when it's left out in the wild. Okay. When it's not part of an atom. Okay. When it's not in captivity. I forgot which of these. It doesn't matter for my example. Decays in like six minutes. Okay. Okay. What happens if you take that particle and speed it up in a particle accelerator? So, you take a community of these particles, speed them up, calculate. Wait a minute. The internal wristwatch on these clocks says they should live longer. And sure enough, their decay time takes longer.

8:27Wow. That's. Oh, my God. Yes. Yes. Oh, wow. Yes. And that becomes living proof of what Einstein said. Yes. Because we can't go half the speed of light. Right. But you can accelerate a particle to do that. Yes. And it has an internal built-in clock that decays after a certain amount of time. And there they are taking longer to decay in the exact amount that Einstein predicts. That is genius. So, we don't make this stuff up. Okay. Yes. It is genius. It's like triple genius. All right.

Cosmic Drafting

8:58Now, let's take this to an extreme level. Right. Let's go so fast that we're going the speed of light itself. Right. Well, we can't do that because we're made of material substance. And there's no way to do that. But there are things that travel at the speed of light. And what is that? Uh, those would be photons. Yes. Thank you.

9:23Those would be, like, your finger gesture. That would be, I would say, what travels at the speed of light? Light does. Yeah. Okay. I was about to say light. So, if photons had a clock, the clock would never tick. Nice. Which means, when I go to a mountaintop, as I did in graduate school, to observe the center of the Milky Way galaxy for stars that emitted their light 30,000 years ago, traveling through

10:01the gaps of interstellar space, and they move through space, come through Earth's atmosphere, they come down into the telescope, they reflect, go back to my detector, and land on my CCD chip,

10:15that photon, when it was born, at the star that emitted it, was detected at my telescope in the same instant, according to the photon itself.

10:34Live fast, die hard. The photon has no knowledge of that trip. Right. Because time did not exist for it. Oh, that's great. And I'm saddened that many of these photons, like, hit people's tanning on the beach, you know? And imagine traveling 30,000 years and land on someone's buttocks. Yeah, very sad. With the telescopes I collected, I'm now decoding the nature of the universe. And some photons go right on by Earth and are still moving.

11:05But they have no internal time clock. Wow. And they're just traveling through, like, I hope when I'm born, I hit a telescope. Bam! You're born and you're hitting a telescope.

11:18Yeah, that would be an interesting, what do I want to be when I grow up? You know, or the instant I am emitted, where am I going to be absorbed? Where would I like to be? Right, right, right. And so just the idea that light can move across the universe and have no, and not age. This is a fascinating fact to me. Wow. So, yeah. That is more than fascinating. Yeah, yeah. I mean, that's mind-boggling. Yeah, yeah. So, that is light, the age of light. It's like, it doesn't age at all. I am convinced that all of you guys secretly microdose and smoke weed.

11:55I'm just, I'm- That's another episode. That's what I'm saying. Another episode.

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Patreon Support

16:04This is StarTalk with Neil deGrasse Tyson. Do you like these, these explainer? Of course.

16:21One, because Neil-splaining has always been good for me. Neil-splaining, that's the thing. Neil-splaining has always been good for me. Okay. You know? All other splainings are not good. Man-splaining. Yeah, you know, that's exactly. Man-splaining ain't good. You know what I mean? Black-splaining, white-splaining ain't good. But Neil-splaining, it works. That's a whole other thing. Yeah. Thank you for that, those words of encouragement. So I'll just continue.

Gravity Assist Details

16:45Cool. And what do you got? So I got today, we've all heard of gravity assists for a spacecraft. Yes, that was in Space Jam, right? It's a gravity assist. Oh, that was, oh, that's it, people. I just retired. It's over. Because that was the worst I've ever done in my life. Jesus. So a gravity assist, the way people typically think about it is you send out a spacecraft and you want it to give it more speed than it currently has.

17:16Right. And so you find some planet that it sort of falls towards. And of course, it'll speed up as it does that. Right. And we think of it as kind of a slingshot. Obviously, it falls not towards it, but towards the side of it. Yes. Otherwise, it's not a gravity assist. It's a gravity crash. Exactly. So you want it to sort of swing by, and it picks up speed in so doing, and it flings out the other side. And if you angle it right and position it right, you could head towards your next destination.

17:48And as a result, you can have multiple destinations in the same voyage. So famously, Voyager 1 and 2, this is back in the 1970s when it was launched, they had trajectories that, well, let me say that differently. The solar system's planets were configured in such a way that it could get multiple planetary assists, multiple gravitational assists. And by the time it was done, it had so many gravitational assists, it had enough energy to leave the solar system entirely.

18:24Wow. And you could end up doing that without using a very big rocket to begin with. Right. So you're basically exploiting the gravitational attraction of planets for your speed rather than spending money on fuel. So it's the poor man's way to get out of the solar system. It's basically cosmic drafting. Drafting. Oh, I like that. Cosmic drafting. It's just like, why should I pedal? Let this sucker pedal for me. Think about this. Because as you approach a planet and its gravity attracts you, everyone has said and it believes and thinks that it pulls you in and then flings you out the other side.

19:04But wait a minute. Yeah. Just like there used to be for me with women at a nightclub. Oh, is that how that worked for you? Yeah, man. There was an attraction. Pull me in. And they'd be like, oh, no, no, no, no, no. You got it. Nuh-uh. Out the other side. See you. Out the other side. See you, bro. Completely symmetric picture there, right? Exactly. So the problem with thinking of it that way is the same gravity that's pulling you in is also preventing you from leaving.

19:35Right. Okay, so you'll speed up as you fall in. But now as you try to escape, the gravity's saying, no, I'm pulling you back. Right. So it turns out if you look at the pure gravity picture, it is exactly symmetric to the planet. Right. Okay. The planet pulls you in. You gain speed. You have maximum speed right when you're passing the planet. Now you want to exit the planet. The planet starts pulling you back.

20:05Right. Every time I try to get out. Your speed falling in and your speed going back is an exact mirror image of your motion. Okay, so then the question is, how do I end up getting all this damn speed? Where are the sleet shot effect? Okay, this is something that's hardly ever explained. And that's why we have these explainer videos. Cool. So here's the answer. It turns out, if you approach a planet from behind.

20:40Okay. Okay. There it is orbiting the sun. Right. And you approach it from behind in its orbit. Right. Not only will the gravity pull you in, but you will gain speed just to catch up with the planet in its orbit. That makes sense. Yes. Right. How are we going to catch up? How are we going to hit the planet, come near the planet, unless you have the planet's orbital speed? Right. The planet's orbital speed has nothing to do-

21:13With the planet. With the planet's gravity. Correct. Okay. So even though the gravity is symmetric, all the speed and energy you gain falling in, the planet takes back away from you. That's symmetric. Right. But the speed you get from catching up with the planet in the orbit is not symmetric. Oh, look at that. Okay. And so what actually happened is you were tugging on the planet, okay, as the planet was moving and you were speeding up because of this.

21:47But what it means is you stole some of the planet's orbital energy to do this. Wow. They don't tell you about that. No, they don't. So you, basically, you approach the planet from behind and you just like- Don't make a ghetto mugging out of this.

22:04Yo, give me some of that speed. Don't turn around. Don't look at my face. Don't look at my face. Just give me the speed. Nobody needs to get hurt here. And then you take it and you keep going and you got the thing and it doesn't. And it doesn't have it and you have it. So this, these are, this is the art of the, of the slingshot. Dude, that is, that's pretty amazing.

22:35That would make sense. Yeah. You can slingshot off of anything. Right. We've had planets orbit the sun launched from earth and then slingshot around earth twice. Right. Wow. Okay. On two, now it takes longer, right? It's, that's if you're not in a hurry, you do this and use earth to slingshot. You could slingshot off the moon. You could slingshot off of Mars. Okay. It doesn't matter what planet you want to slingshot from. Right. In the case of Voyager, Voyager one, I think it was, it's slingshot.

23:09What's past tense of two slingshot? It's slingshotted. Slingshot. Yeah, yeah. Slingshot. Slingshot. It was slingshot. It's slang shit off of, off of Jupiter. Right. And so people think, well, Jupiter has big gravity. It'll get a huge speed. It's only getting Jupiter's orbital speed. Right. Doesn't make that clear. Look at that. And Jupiter's traveling slower than planets that orbit closer in. So the gravitational pull cancels out, but the orbital speed is what's left over.

23:41And that's what you ended up stealing in order to get the speed to go. And if you want an inverse mugging, which no one will actually want to do in space. If you, you can fall towards the planet. Right. Opposite the direction it's traveling. Oh, wow. Okay. And if you do that, then you have sped up the planet. It eats some of your, or your, your, uh, uh, trajectories energy.

24:13And you'll come out the other side moving slower than you did before. Oh, so you could actually use it as a break. As a break. That's correct. Oh, wow. Okay. This is, that's fascinating stuff. That's cool. If you want, if you need it to break in space, that's a way. And it takes a long time to like line up and make it all happen. So there you have it. Wow. Look at that cosmic drafting and space breaking. That's amazing. And so the more, the more times you do this, the more energy you have, the more speed you accumulate. And that's how we leave the solar system.

24:43Cool. Yeah. And you might ask, but you didn't, uh, if you, if you, if you, if you slingshot off of Mars, like 20 times, like what happens to the Mars orbit itself? If you're taking away its energy, you haven't asked that. No, I don't, I don't, cause you don't care. I was going to say, you know, I'm not worried about Mars. Okay. I think Mars is going to be okay. But anyway, what does happen? Let's say over, over, over, over, over.

25:14I mean, you're, you're, you're basically siphoning off a tiny little bit of energy. Siphoning off a tiny little bit of energy. So, okay. So here's the thing. Uh, you know, maybe in a trillion years, if you did this every day, it would matter. But the mass of these objects relative to the mass of our measly probes, okay, that ratio is so huge that it's like a gnat flying full speed ahead into an elephant. The elephant doesn't say, you know, watch out, quit your shoving this, the mass difference

25:47is so huge that it's not relevant. It's not important in what's going on in the solar system. But in addition, take earth, for example, in any given day, we plow through a hundred tons of meteors every single day. Wow. Tons. So this stuff fallen and, and, and this stuff, so it's, don't worry about it. We have other things we should be worrying about, like climate change. Yes.

26:14Tell me about it. You know, it's, if you're worried about, oh my gosh, what, how about Mars? Worry about your own damn planet. How about that? I'm all about that. Speaking of Mars, you said, worry about your own planet. Don't worry about Mars. And so I got both of them in one. I got a Mars pad from the out of this world, uh, collection from soul guard. Right. And check this out. Every single suitcase that they make pulls about 229 bottles of plastic out of the environment.

26:49So here we, yes. So here we are with Mars and we worried about our own planet at the same time. Boom. Wait, wait. So you're saying I should drink more plastic bottles. No. You can make more of those, that luggage. No. Is that the takeaway? No. No. I'm saying for the idiots that drink plastic bottles, this is part of the solution. And for the smart people who want to buy this and help, that's what they should do. Okay. So, so it's not only gets the bottles out. Uh, if you like the universe, if you love the universe, you got one that looks like Mars.

27:23Yep. That's right. That's right. Very cool. 12 million plastic bottles pulled in 2021. Right. See, that's what we're doing here. Wait, Chuck. Do I recognize Valles Marineris on that? Really?

27:38Don't pretend like. I'm like, cause here's what I'm saying. Do you?

27:45No, it looks like a high resolution image of Martian surface. It's not just like red, right? No. Pretending to be Mars. It is Mars. It's got very good detail on the surface. So. Highly recognizable if you're Mars fluent, which apparently you're not. No. Okay. I don't speak Martian. I'm sorry.

28:04Valles Marineris is basically the Mars Valley. And it's a huge canyon, way bigger than the Grand Canyon here on Earth. Okay. And it's a very striking scar in the Martian surface. Clearly, Mars has had a whole lot of activity long ago, shaping and forming and reshaping its surface. And that's one of the bits of evidence of it. So that, that, that adds to the authenticity of what you got in your hands there. Very cool. I'm just going to let you talk while I sit here and play Black Van of White.

28:35Is that how that goes?

28:42But I need a vowel though.

28:46I got a, I got a few of them right here. Oh yeah. There you go. I can, I can tell you this, that there's nothing more boring than people's luggage. Think about it. You're absolutely right. By the way, speaking of that. So now there's a piece of luggage that like, that's good. I want one. There's some exciting looks. By the way, the cool thing about this, not only is it like it's Mars right here, which means that when it comes down. Can't argue with Mars. When it comes down the chute, right? Okay. Mars down the conveyor belt. Mars is coming down the conveyor belt.

29:16You'll be able to recognize yours. And as a matter of fact, you can turn to somebody and go, get your ass to Mars. And, but don't take my luggage while you do.

29:31Okay. Very cool. I'm glad y'all are working on good stuff. That'll love this company. Soul guard. All right. All right, Chuck. So that's all we have. That was great. I love it. So now, you know, and I never thought to analogize a gravity assist with a mugging.

29:49I'm glad I could be observed. Yeah. Thank you, Chuck. As always.

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Brightest Star Discussion

32:04What's the brightest star in the nighttime sky? Are we talking my career here, Neil? Well, I'm just saying, I've been waiting for us to get around to this.

32:17How bright is your star, Chuck?

32:21Yeah, no, if it were me up in the sky, I would just be a dim spot in the Milky Way. It is funny that a fundamental word in all of Hollywood is derived from my profession, astrophysics. It is the most fundamental word of all of Hollywood. It is. Are you a star? Meaning, are you burning thermonuclear fuel in your core? Exactly. Right. And the Walk of Fame? It's a star. It's a star. That's all astro. Yeah. Well, it's said that from everything I've ever heard, that's the North Star.

32:54That's what people say. Well, that's the North Star. You can always find your way home because it's the brightest star in the sky. Just follow the North Star. Yeah, so in my experience, nine out of ten people will say that. Yeah, okay. They'll see the first bright star after sunset and then assert that it's the North Star. When in 100% of those cases, they're looking at a planet. Well, that makes sense because a planet is right there. Yeah, well.

33:26The planet's right in front of our noses. The planets are right here, man. But for me, the funny part is they'll make a wish on the, you know, star bright, star bright, first star I see tonight. First star tonight. Right. And then they make a wish. And, of course, the wishes don't come true because they're wishing on planets. That's why. You never knew that. That. Okay. I want to explain that to any kid now. And then if you're not wishing on the star and because you know that they're planets, it means you know enough science not to be wishing on stars.

34:01That's pretty cool. It all balances out. And it's so funny that you say that. It just popped into my head what a culturally entrenched sentiment that is. Wishing on a star. I mean, there's songs about it. It transcends, you know, geography and culture. You know, you have it in pretty much all kinds of writings. Wishing on a star. That's pretty wild. Yeah, and I'm honored that my field supplies this level of cultural referencing to all that we do.

34:39So, yeah, so the North Star is not the brightest star in the night sky. Okay. I just want to make that clear. Okay, now, so now here's the thing. Yeah. Because what is the North Star, then? Like, what is the North Star and why is it of any significance if it's not the brightest star? There you go. So, we'll get to the brightest star in a minute. So, the North Star is the star in the sky that's closest to where Earth's axis points on the sky.

35:17So, you have a rotating Earth, and it's just sort of rotating. Right. And the axis is just sort of sitting there as Earth spins around it. That axis is pointing to a spot in space. Okay? In the sky. Gotcha. So, we say, is there a star near to that spot? Because then we'd always be pointing in that direction. Right. So, the star closest to that spot is the North Star. And the North Star has a name. Did you know this?

35:48I want to guess, because the only star that I hear the name of all the time is the Dog Star. Yeah. No, that's not correct. Okay. Well, there you go. I said it was a guess. It's not serious. It's not serious, the Dog Star. Okay. Yeah. Yeah. The Dog Star is serious. Serious is the Dog Star. Not the North Star. So, the name of this star is sensibly Polaris. Oh! For the pole or the axis. Polaris. Polaris.

36:19And, in fact, that was the name, I think, of America's first nuclear submarine, Polaris, that could launch intercontinental ballistic missiles. We're about to drop a star on you.

36:31So American. I know. That is so American. Okay? We're about to drop a star on you. That produces energy to vaporize you just the way the centers of stars do. Yeah. All right. Right. It's the same thermonuclear mechanisms going on. So, anyhow. So, it's got a name, Polaris. Now, the Big Dipper, okay? The lip of the Big Dipper, this part right here, okay? The lip. So, there's a handle, and then there's the cup, and the lip is the front edge of that

37:04cup. Right. That points to the North Star. Okay. Okay? That's how you can always find the North Star. Got it. Because the Big Dipper is very obvious in the Northern Hemisphere. Absolutely. Absolutely. So, and then it points, and you go, like, four segments up, and then, boom, there it is. Okay. So, there are a couple of issues with this. First, the North Star is not exactly above the pole. Okay? You can fit two full moon widths between it and the exact spot over the North Pole.

37:43Gotcha. All right, which means if you took a camera and a long exposure photo centered on the North Star, the North Star will not be pegged in the middle. You'll see it make a circle.

38:01Interesting. So, it is not exactly above the North Star. And the reason why you're seeing it make a circle is because you have the long exposure and the Earth is rotating where your camera is? Yes, exactly. Okay. And so, otherwise, if you just take snapshots, you just get the stars where they are. Right. But if you take a long exposure, you get the stars blurring, basically, but they blur with the rotation of the Earth. Gotcha. Gotcha. And so, you'll see that it actually would trace a circle around the actual North Pole. Because people are saying, isn't it amazing that we have a star exactly over the North Pole?

38:35Oh, what are the odds? Well, it's not exactly. The odds would be zero.

38:42That's a bad bet. Don't take the stars. It's not exactly over the North Pole. Not only that, the lip of the Big Dipper kind of misses the North Star. If you did an exact line, it's off. So, there's a lot of fakery going on. Not bad fakery, but just people want the sky to have more meaning than it actually does. Wow. And so, you say things that are sort of partly true just because you feel better about what it is you're talking about. Okay. So, the North Star is kind of like, directionally, it's kind of like getting directions in the

39:17hood.

39:19It's kind of over there. Yeah. Yeah, man. So, what you want to do, you want to keep on down there, you want to keep going and going, right? Right? You're going to come to, so it's a car, right? But one of the wheels is up on a crate? Yeah. Make it right there. Make it right there. All right? You're going to keep going, right? Just keep going and going, right? That's right. Directions on the sky from the stars are exactly like that. So, now let me tell you how bright the North Star is. It's not the brightest, but let me tell you.

39:51Take a guess.

39:56I'm going to say it's a B student bright.

40:01Okay. It's not in the top. First of all, how do you measure brightness in the night sky? I really don't even know that. But we have meters that do this. This is science. You don't have to worry about that. We got this. All right.

40:16And even if you didn't have meters, you can say, yeah, that's brighter than that. And that's dimmer than that. Yeah, we got this. Okay. We've had this even since before there were telescopes. Okay. So, it is not in the top 10. Oh, no. It is not in the top 20. Oh, goodness. It is not in the top 30. Dad, North Star. What are you doing? It is not even in the top 40.

40:46Oh, my God. The North Star is like the United States with respect to math and science. We say we're number one, but we're 47th. The North Star is the 49th brightest star in the night sky. Oh, my gosh. It is completely uninteresting. It is easily missable. Right. It is does not call attention to yourself. That's why you need the lip of the Big Dipper to find it.

41:16To find it. Because you actually need a pointer because it really isn't remarkable at all. It is not remarkable. Not remarkable. Wow. It kind of reminds me of somebody I know. You sound like you should have your own TV show, reminiscences of everyone you grew up with.

41:38The stories. So, yeah. So, the North Star is just lame. I mean, it's just embarrassing. And meanwhile, people think it's the brightest star in the night sky. And that's what's weird about it to me. I just, because they've never checked. And so, this is the lore overriding people's curiosity. I wonder how Venus feels about that. You know? Venus is the most mistaken object for the North Star because it's the brightest in the night sky, the morning sky. Venus is sitting around like, ah, just like a man.

42:10Just like a man. Here I am, just as bright as I can be. Every single night, I come out. Is that what Venus sounds like? Look at me. And you know what they say? Oh, my God. Look at the North Star. Once again, a man just taking my credit for the hard work that I do. Okay. And no, there doesn't happen to be a star in the South Pole. It's just a big empty spot. There is a star closer to the South Pole than the North Star is to the North Pole. But it's even dimmer. And we don't call that the South Star? You can, but it has a name.

42:42It's called Sigma Octens. And it's very unassuming and nobody cares. I don't believe. You know why nobody cares? Because its name is Sigma Octens. It's like, don't nobody want to talk about Sigma Octens? Sigma Octens. Because there's a constellation called Octens, which is an octant, which is an early version of a sextant. And there's a lot of navigational instruments among the constellations of the Southern Hemisphere. You know why? Ah, because when Europeans got to the Southern Hemisphere and decided to map the stars, we

43:18had already begun the Industrial Revolution. And so they weren't thinking centaurs and Greek mythology. They were thinking, oh my gosh, I'm going to put some badass equipment here. So there's an architect's table. There's a telescope, a microscope, a sextant, and an octant. Wow. It's all there. These are all constellations of the 88 in the night sky. Wow. So one last thing about the North Star. So you can picture this. If you are Santa Claus looking straight up, what star do you see?

43:51Looking straight up, you see a dead spot. Well, yes, because we just learned that. Right. But- Oh, I thought it was a trick question. No, that's not true. No, you look up. Santa Claus will look up and see the North Star. See the North Star, right. Okay, so how many degrees up is that from the horizon? Yeah. From the horizon. Well, no, that should be nothing. He's already there. No, no. Degrees from the horizon to straight overhead for Santa Claus. Oh, that's- Let me see. Because he's at the top of the world. So the degrees on the horizon-

44:21No, forget the- It doesn't matter. Just- Yeah, Santa Claus is on the, quote, top of the world. Sure. But now he wants to know how high up is the North Star for him, above the horizon. So how many degrees is that? Oh, that's straight up. That's 90 degrees. 90 degrees. 90 degrees. What is the latitude of the North Pole?

44:43360 degrees.

44:46What is the latitude of the North Pole? It's 90 degrees. 90 degrees. Thank you. I just love- No, I said that because I wanted to see. This is what I love. This is what I love you being, the educator that you are. Because I'll do that, and I'm just waiting for the reaction. Because if it were me, I'd be like, man, what the hell is wrong with you? You dumb. What's with you? Hey, you do this. This is what you do. I gave you a second chance. I gave you a second chance. You always do this. You're like- I said, my boy knows better than this.

45:17I'm going to give him a second chance. I'm not going to say a damn thing. He's going to fix his own damn mistake. Exactly. Right. But I love it. I love it. Go ahead. The North Star is 90 degrees up when you're at the North Pole, which is at a latitude of 90 degrees. That is not a coincidence. Okay? If Santa Claus marches south, the North Star will get lower and lower and lower in the sky. Santa Claus gets to the equator. Mm-hmm. The North Star is on the horizon. The latitude of the equator is zero.

45:47Zero. The elevation of something on the horizon is zero.

45:53So, the elevation in degrees of the North Star above your horizon is your latitude on Earth. Oh, because it follows all the way down. It follows all the way down. It follows all the way down. That, well, that's pretty interesting. Yes, very interesting. And so, this was an important navigational tool. That makes sense. For everybody. Right. Right. Right. And, of course, the Underground Railroad, follow the North Star, because if you just walk towards the North Star, you'll eventually reach Santa Claus. But Ohio is good enough.

46:24Oh, yeah. Tell me. Who knew that the North Star was such a poser? Very much a poser. Actually, it's not its fault. It's people want it to be so special, and it just isn't. So, I have more to tell you about how unspecial it is.

North Star Facts

46:48Oh, awesome.

North Star Facts

46:49We're at 49th. We're at 49th. We're at 49th. Yes, for those who missed it, the North Star is the 49th brightest star in the night sky. Right. And in the night sky, it's not saying, here I am. Right. It is not doing that. All right. So, but wait, there's more. Earth's spinning on its axis, and it's at its North Pole, points upwards, close-ish to where the North Star is on the sky. All right, all right, what I didn't tell you is, I don't know, no one has them anymore.

47:21Do you ever play with tops as a kid? I did. That's how old I am. Of course. You play with the top, and it spins, and then eventually begins to wobble? Right. Okay? Right. Okay, we have an official term for that. It's called precession. Precession. It's wobbling. Precession. That's an official term. So, Earth wobbles. Okay. Do we spin once in how often? How long does it take to spin once? 24 hours, I guess. Thank you. Yeah.