Is the Earth round?

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Speaker 1: Hey, Daniel, how do you feel about skepticism. I don't know, I'm a little skeptical of it. Well, I mean, do you think it's always a good thing to be asking questions? I'm always in favor of questions. I mean, that's definitely how we got where we are, and that's how we learned so much about this incredible universe. But you know there are caveats. Okay, so I got a good one for you. Do you believe the Earth is round? Actually know that Earth is not round? What? Are you one of those flat earthers? No? No, No, those people are crazy. There are a lot of them out there. I know there are flat earthers all around the globe, all around the globe, not on top or below the globe exactly. Well, what's your take from a physicist? The official answer is Earth round or flat? It's a false choice. The answer is neither. Stay tuned and find out. Hi. I'm Jorge, I'm a cartoonists and the creator of PhD Comics. Hi, I'm Daniel Whiteson. I'm a particle physicist by day and a podcaster by any other time. And welcome to our podcast. Daniel and Jorge explain the Universe, a production of I Heart Radio, in which we try to explain crazy things about the universe, sometimes things really far away, sometimes things in our neighborhood, sometimes things right under our feet. I'm sorry. We try to tackle big questions, small questions, Questions you think you know the answer to, but maybe the universe has a way to surprise you. That's right. Round questions, flat questions, square questions, squiggly questions, and squishy questions. We love all the questions. Questions are our business. Who I like that as our company? Mottel, that's right. Do we have a company, Daniel, Um, we should make one. Yes, We're in a good company. All right. Well, so today we're tackling a question that obviously humans have been um had been struggling with for a long time, and I think for pretty much the last couple of centuries, people think we know that the answer to right. That's right. This is the kind of question people ask, and it's a kind of question it can be hard to answer immediately just by looking at what's around you. But it's a fun question because it's the kind of question that you know, sort of the beginning of cosmology. It's like, let's try to get a larger scale understanding. Let's try to understand not just the world I live in every day when I walk to my friend's house or go to the river and wash my food, but like the larger context where we find ourselves and how it all works. So the beginning of that intellectual struggle, yeah, kind of asking like what's beyond what we can see and touch? Right? That's right? How does it all fit in? Right? Like, you know the picture frame that my life lives in. Am I a tiny little dust mode in the corner? Am I in the center of it? Um? How big is that picture frame? You know? This? These are interesting questions, and I wonder sometimes like who were the first people to think of those questions? You know, as humanity emerge from you know, pre humans into an intelligence, Like when did people post humans? When did people first start to ask these kinds of questions? You know, how big is the earth? What is its shape? Um? You know, where is the sun? All these kind of questions about our basic cosmology? Yeah, Like who do you think was the first sentient being? That just kind of wondered, like if I keep going in that direction, what's going to happen? Or if I shoot straight up, what's going to happen? Or straight down? I don't know, but I think the answer would probably um make you happy, because I think that a lot of anthropologists imagine that humans have been intelligent for tens of thousands of years, and the major evidence of that is basically cartoons. Oh yeah, that's I always say, that's a sure sign of intelligence to draw them, to be able to draw them, or the sign of the society is about to crumble, that's right, and good extinct like those ancient civilizations. No, but it's cave paintings, right, I mean we can see which are basically cartoons like people doing symbolic thinking and describing dogs and buffalo and all sorts of things on the walls of caves describing them. I think that's the first sign of intelligence. So probably around then people started to have thoughts about, you know, their situation and how it works and what's the bigger what's the bigger situation that their life is in, and so I think that's what led them to ask this question. So yeah, that's kind of the question is, uh, you know, what did humans think about when they asked themselves? What happens if I keep going in one direction. And so today on the program, we'll be taggling the question is the Earth round? That's right? What shape is this crazy rock that we're living on? And you know, you can look at a lot of things that people describe early on, you know, drawings from hundreds or thousands of years ago, people trying to draw maps and what the Earth looked like, and there's some pretty crazy ideas out there. But if you just sort of look around you, or if you're just like born in the world and you look around, the world looks pretty flat, right, Like, as far as you can see, the ground is pretty flat. You think that we're sort of on a on a flat surface, right, because you your immediate surface around you is flat, and kind of you look out a little bit further, it's still flat. Yeah, And it seems simple, right, And if you're the goal is to understand around you, well, what's around you, then the first thing you're gonna do is think of the simplest thing. And the world looks kind of flat, and you can't see that far away, and you know, many surfaces, if you're only looking a small portion of them, look flat. I mean, the Earth could be all sorts of crazy shapes, and if you only look in your neighborhood, it might look flat in the vicinity. Yeah. So, and I imagine most of our listeners, um probably think or know that the Earth is not flat. But we're wondering if people actually know the real answer to the question, is the Earth round? Yeah? Or what is the shape of the Earth? That's a different Russian What shape is it in? That's right? What shape it is it? Politically fitness wise, I think we should not be judgmental the Earth. I think we should be Earth positive, you know, I think, um, this is the one only one we have. And he gets depressed and you know, decides to end itself and plumbing into the sun. You'll be sorry. That's right, the Earth is round and proud? That's right? Exactly. Who wants to be on a slender planet anyway? You know? All right? So, as usual, Dad, we were wondering what people how people out there in the street would answer this question. And so Daniel went out there into the street and accosted innocent bystanders and asked them a very basic question. That's right. And not only did I ask them if they believe the Earth was round, but I asked them how they knew, which I thought. Let's some of the more fascinating answers. Well, let's see what people had to say. Do you believe the Earth is round? Yes? Why what evidence do you have that the Earth is round? I think it is best answered by astronomy is like, of the Earth is round, we go. If the Earth is not round, you go. You start from a point and you keep going and you learn reach to this to your first place. Do you agree with me? Says one reason? And there are I'm pretty sure there are like lots of proofs about it. Yes. Why whateverence do you have the Earth is round? Because the idea that satellites are free fall and that they free fall around the Earth. So if you throw a ball, it goes, it has a curve, and so that kind of goes ahead improves that like we're falling innocence, and so that can go ahead and explain how satellites can fall around the Earth constantly cool orbits. Okay, good answers around, Yes, why what everything is do you found? Well, based on what everyone else has said, I don't know, there's some evidence, but I do believe the Earth is around. Do you believe that the Earth is round. What evidence do you have inund airplanes? I don't know, pictures of like from the I like that, all right, pictures from space other other astronomical objects are also around, so good point other points around. I do believe there is around. Why is that? Whatever you want? I believe this is around because just what I've learned in my education growing up middle school to high school to college, it's just what I'm familiar with. So yes, why whatever pictures NASA? Al right, pretty no flat earther is you couldn't find any flat earthers out there in Irvine. That's right, good job you see, irline. I was really relieved to not run into any flat earthers. I mean I was a tiny bit curious, like, what would I do if I met a flat earther, Would I like engage them in debate on the spot and be able to persuade them. Anybody who believes the Earth is flat is probably not really open to actual scientific dialogue on the subject um. But I was also sort of relieved that, like in this educational community, at least we've succeeded at that level that everybody understands the basics of the world around them. I think the flat earthers only exist on the Internet. Sometimes I wonder if the flat earthers are all just trolls, you know, if they're just being ridiculous to make everybody mad because they get their kicks by pissing people off. But I did some research, and there's a pretty hardcore group of people out there that really, honestly, sincerely believe the Earth is flat. So you got pretty much everyone said yes, uh, and they all had all pretty good reasons for believing that the Earth is around. Yeah, I'll be great. Some of the reasons as excellent, and some of the reasons is a little weak, like the weaker ones are like, well, everybody says so, you know, and that's okay. Like you, you know, you should be a skeptical person. You should try to think about these things for yourself. On the other hand, like if there's something that everybody is believing, probably it's true. I mean, there's probably a good reason why, you know, scientists and experts and everybody are saying X, y Z is true. So while you should be skeptical, you shouldn't just toss out everything that experts are saying just because you can't prove it yourself. Well, it gets a little bit philosophical, because I mean, it's impossible to know everything and to be aware of all the evidence for every single thing out there in the world, and so at some point you do sort of have to be like, all right, most scientists believe this. I guess it's probably true. That's right. Yes, sometimes you have to talk to an expert. And you know, what's the point of talking to experts if you're not going to believe what they say? Right? Like you ask me physics questions. You don't go off and double check every single thing I say? Or do you a triple check it? Daniel? Does that mean you have to other physicists on the line who are like giving the thumbs up of the thumbs down in your secret Daniels in my pocket? Man, I'd like some secret Daniels in my pocket. Do some of that work for me? That'd be awesome. I have a Daniel Grayson and a Daniel and defeat green Sun, different shades of Daniel, all the colors of Daniel, different fifty shades of Daniel. You know there's a fascilating book. I don't know what that book is about. I have to be the fan fiction version of this podcast, they're not safe for persion. Um. The other answer is that I really liked were the one people who have their own reasons, you know, who had thought about it. They're like, well, that's impossible, and here's why they could actually make an argument, you know, like, um, everything else out there is round, or we know that things are in orbit, right, these are good reasons, um. Or you know, people who don't think that the government is lying to them about everything. They believe the pictures. They believe that, they believe the you know, they believe the pictures of other I mean, and I guess you can see other planets, right, you can see the moon, and with the telescope you can see other planets. Yeah, you certainly can. You can see other planets, and they're all around. Pretty much everything out there in space above a certain size is round, and for good reason, right, it's or round dish at least. And the reason is just gravity. You know. Any if if you have a big enough object, it's gonna have a lot of gravity. And then if it's not around, that means that some part is further from the center than another part, and eventually it's just going to break and roll downhill like all mountains on Earth. All mountains on Earth will event actually crumble, right due to rain and gravity and other forces. Now, a quick word from our sponsor if we're going to answer this question, is the Earth round? Let's let's start kind of where humans started, right, And so let's start first of all with how do we know the Earth is not flat? Because that's kind of what your intuition would tell you if you never traveled or seen pictures from space. Right. Okay, so if you haven't seen pictures from space and you're like, you know, natural science kind of person a few thousand years ago, how might you figure out that the Earth is not flat? Well, the you know, the history of it is that people did things like they did experiments where they stuck sticks in the ground and they look to the shadows. Now, if the Earth is flat and the sun is just like above us, then every stick is going to have a shadow the same length. But if the Earth is round, then those shadows is going to be different lengths at different places. And so this is like what a Greek guy did. He put tall sticks in different towns in Greece, and he knew how far away those towns were from each other, and he measured the angles of those sticks and the length of the shadows, and from that he could estimate he could prove that the Earth was round and estimated size to pretty good accuracy. What is this a like a apocryphal story or for real? Hey? You know everything about ancient Greece could be apocryphal, right, The whole thing could just be invented as far as as far as we know. Um, But you know this is um as far as we understand it, This really happened, you agree, Greece. Let's talk about whether Greece really happened? Right? Is Grease just a conspiracy man? No? But you know, the thing about ancient Greece is that we know so little of what happened because the Dark Ages and so much of what they did was destroyed. And you know, we have like a tiny trickle of the vibrant intellectual product of that civilization. So we really don't know what was going on in ancient Greece. We know a tiny little slipper, which is such a tragedy. It breaks my heart to think about all those great ideas that were just like lost, you know. Um. But anyway, all those big wine parties. No, it's just to me. It's it breaks my heart when I when I think about you know, um, progress that's been made, Things have been figured out, mathematics has been developed, and then just just discarded or lost, you know, like in huge fires of ancient libraries and destructions of civilization. Anyway, we do have some clues about what happened in ancient Greece, and there are stories about the about folks measuring the size of the Earth using basically just two sticks in the ground. Okay, and so the ideas that he planted a stick in one town and then it's kind of like if you plant the stick in California and then you run over to Florida and plant another stick there. At any given time of the day, the shadows are might be different. Yeah, there will be different lengths, right, because those two sticks have a different angle with respect to the sun. They're seeing the sun at different points in the sky. Yeah, exactly. And if the earth, but if the Earth was flat, the shadows would be identical. That's right, that's right, Yeah, that's that's the point. Yeah. Um No, they wouldn't be the same, would they, But there would be the same length there might be a different angle, but there would be the same length. Pretty sure, Pretty sure. I mean it depends on your particular flat earth model, right, But on a sphere, it's definitely true that there are different lengths and angles and that you can use that to measure the size of the sphere. And another key element, of course, is knowing that the Sun is really really far away, so that the light that comes from it is basically always parallel, because otherwise you could try to explain the different angles that you get from sticks to different places and make it consistent with a flat earth. You could try to do that by saying, oh, well, maybe the Sun is really close to the Earth and that's why we get different angles right over a flat earth. But that's silly. We know the Sun is far away. If the Sun was that close to the Earth, you could see it's apparent size like change as you move around the Earth, and we don't see that. So that's an important part of the argument. Interesting, but wouldn't that require you to have like a walkie talkie between the two places, you know, to say, all right, right now, measure the length of the shadow. But if you don't have that instant communication, how would you like coordinated and know that it was measured at the same time. That's a good question. I don't know how they managed it. Maybe they had walkie talkies in ancient Greece increase, They definitely didn't. We don't know anything they could have burned with the labrary. I mean that the power of the test is greater the further the sticks are apart. But I don't know how far apart they have to be for you to have a measurable effect. It might not have to be very far, you know, so you might be able to say, like, all right, we'll both walk for an hour and then plant a stick and then measure the length, and it might be enough, Oh I see, or maybe like a smoke signals or something like if it's several miles and you can still do it, yeah, smoke signals exactly. Um, you'd be good at inventing physics experiments in ancient Greece. Yeah, I definitely want to around. Um. But there are also other ways. You don't have to do two sticks in the ground, Like, there are other ways to figure out that the Earth is round, even even without technology. All right, what are those ways? Well, you can just look at the stars. Right, travel the Earth and look at the stars. You see different stars from different parts of the Earth. Right. If the Earth is flat, then everybody should be seeing the same sky. I mean, you'll be seeing it from a slightly different point of view if you're in a different spot on the Earth. But some stars are blocked by the earth. Right you walk from you walk from North America to South America, you're gonna see different stars in the sky. Right, the northern stars you can't see them because the Earth's curvatures in the way. Oh I see. So if you assuming you can remember the sky right, or you can draw it for example, Yeah, you heard of that drawing only in caves. I only know that kind. And you can't see the stars when you're in a cave, so you can sort of you chisel along the side of you join on the side of the cave. You walk to South America, you draw another cave, and they're like, hmmmm, I should have brought my cave with me. That's how they invented the portable cave, probably otherwise known as the tent. Okay. So that's another way you would tell, right, is you would uh notice that the stars are different in different parts of the Earth, which means that the Earth can't be flat. That's right, that's another reason. Another way you can tell, again without really much technology, is just seasons. Like how do you get seasons on a flat earth? Right? I mean different parts of the earth have difference. You might say, okay, we can get north, we can get winter the sun goes further away, we can get summer when the sun gets closer. But we have different seasons and different part of the earth. Right, we have summer in the northern hemisphere when we have during the southern hemisphere. How do you account for that? Well, I mean if I if I live thousands of years ago, I mean I wouldn't know. I wouldn't know anything, right for all? For all I know there are gods and weird you know, magical beings that make it winter here, and some are there, yes, absolutely, And there is always another explanation that's like ridiculously complicated, involves magic and gods are like crazy trajectories that can explain all the data. But we prefer the simplest, right, If the simplest explanation is that the Earth is a body just like all the other ones we see, and it looks just like them, and it's also circular. It's also basically spherical, and that explains everything we see. And so it's like, by far the explanation we prefer to, there's some crazy magic aliens out there doing some crazy tricks on us, or here on Earth? Are you here on Earth? Exactly? Okay? Cool? And then what's the last last experiment you as a Greek scientist can do. Well? The simplest one is that you can see hints of the curvature. I mean you can look at ships, for example, coming over the horizon from far away, like what's blocking them? Right? Ships? Um? Coming over the horizon, You're seeing them come over the curvature of the Earth. Right, that's pretty direct right there. Um. And in a similar way, you can see further when you get higher up, Like if the Earth was flat, then you couldn't see any further by getting any higher up, or you can see at a different angle, right, but you couldn't see any further. But on a spherical Earth or nearly spherical earth, the higher you go, the less the Earth's curvature blocks you, the larger your field of view. And that's exactly what you experience. You go to a skyscraper. At the top of a mountain, you can see much further. Okay, so I guess the idea is that is that if the Earth was flat and you were standing at the beach and you saw a ship go off and away from you, it would just get smaller and smaller and smaller and smaller and smaller and smaller and smaller. It wouldn't ever disappear from view, that's right, and you could eventually see it like doc in Japan or something. Right, if you had a super duper telescope. Oh, it would just look really really really small. But you could technically see Japan if the Earth was flat, I mean, Japan is close. You'd be limited by basically the air, right, the air wiggles makes things fuzzy. But yeah, technically you'd be able to see all the way across the ocean. If the Earth was flat. Oh wow, that would be cool. Yeah, that would be pretty cool, wouldn't it. It would be cool was flat, But I guess it'd be nighttime in Japan. That would be awesome. Actually, you could like see different time zones. Oh, I see, but even if I take a telescope and I look out into the ocean with a telescope, I would just at some point see nothing because my line aside would just go off into space. That's right. And if you're on a boat in the middle of the ocean, all you can see is water because everything else is around the curve of the Earth, right, Okay, And then you have one more last um Greek experiment you can do right involving sunsets. Yeah. I mean there's a long list of reasons, some that we believe the Earth is round, but another one is, yeah, sunsets, Like how do you explain sunsets on a flat earth? You know the models I've seen a flat earth to have, Like, I mean, it's kind of ridiculous. But you have this flat plane and then you have the Sun which is really small compared to the Earth, and it's sort of moving around the circular Earth, right for the flat earth like a lamb, because like a lamb just going around around it. Yeah, and it's like shining like a spotlight, like it's directional or something. So you know, I don't understand how you get day or night because the Sun is a sphere. We can see that it's a sphere, right, It's definitely it would shine on the whole surface of the Earth all the time. I mean, if you had a flat Earth with the sun above it, then you would have never had night time unless the sun went below the flat Earth, in which case every part of the Earth would see sunset at the same time, which definitely doesn't happen. Okay. So I think the point is that even if you are super skeptical of scientists and you don't believe anything anyone ever tells you or believe any pictures you see, there are still ways that you could be convinced yourself that the Earth is not flat. That's right. And people did these things and they figured them out, and that's why people believe the Earth is round, even well before we had technology. But now that we have amazing technology, it's pretty easy to discover that the Earth is round. So the because you know, I grew up in um in Panama, and for us, you know, Christopher Columbus was like a big deal, and so you know, as a kid, you just like you always hear like, oh, he proved that the Earth was round. But that's um, that's a little bit of historical Bologna're right, Yeah, I think it was widely spread among anybody who had any education. Uh, the belief that the Earth was round was already widely spread by then, but I guess he was the first or one of the first to really kind of connected physically. I mean, I never really understood that argument because Christopher Columbus was trying to use the fact that the Earth was round to get to India, right, and so he thought he got to India. He's like, okay, look, I got to India, and therefore the Earth is round. But the problem is he didn't get to India, so he didn't prove anything, right. He just proved that if you get in the in the boat and sail, you get to some more land. He didn't really prove anything at all. I mean, Christopher Columbus, Like, there's so much trouble with Christopher Columbus, you know, on top of genocide and miss miss naming Americans as Indians and all that sort of stuff, but he didn't he didn't really prove the Earth is round at all. Okay, but I guess, um, I guess we won't get into the politics of it. It's pretty dark. But yeah, so alright, so then, um, that's how we know that Earth is not flat. And so let's let's get into whether the Earth is actually round or not. But first let's take a quick break. All right, So we talked about how if you were a Greek scientist back in the day, you might be able to figure out that the Earth is not flat. But yeah, how about today, like you know, we we as citizens have every day sittings, have access to a little bit more technology. Um, so how would how could a scientists today without if they didn't believe pictures or other scientists, how could we um find out? How can we be be scientists and conclude that the Earth is not flat? You mean without being Elon Musk and having our own spaceship company and going into space ourselves with that being billionaires, let's say you just have like, you know, a hundred dollars ten dollars in your pocket. Because the billionaire the billionaire demographic of our listeners is probably pretty small, right, but if we have one, hey, give us a call. Please send us an email. All the billionaires out there, please send us an email. We want to record an episode from space that's right, featuring you. Well, first I want to comment on like should you disbelieve other scientists? And again it's healthy to be skeptical. There are times when people everybody's wrong about something, But let's remember that everybody out there doing science is trying to be right, you know, they want to figure it out. They're not out there trying to convince people of things that are not true. Like NASA is not lying to people. There's no crazy agenda, and it's impossible for that to even be Um, it's not practical for that to happen because NASA is filled with a bunch of scientists who all want to figure out the right answer and share it. So if there was some absurd conspiracy to like lie to the public for ridiculous reasons about the shape of the Earth, somebody out there would just prove it. Somebody out there and be like ha ha, look I'm um, I have proof, and somebody would would get the credit for that. So science is filled with people who want the truth and want to share the truth, and sometimes they make honest mistakes. But it's it's impossible to imagine a widespread scientific conspiracy. I think also, even if you don't believe in the altruism of scientists, I always like to think and sit tell people that you know, like if you ever meet a scientist, each one of them, and maybe you can prove me wrong. But like I think, each one each scientists out there would love nothing more than to be the guy that disproves everybody else. Yeah, exactly, even from a cynical point of view, right, they all want the glory that I would love to reveal that all of science has misunderstood something. I mean, I think I've said that on this podcast before. That's my personal scientific fantasies to discover something which forces us to rethink foundational ideas. Right, that's fantastic. Everybody would love to be in that position. And so to prove that the Earth is a different shape than everybody thought, Wow, that would be fantastic. So, yeah, you're right, from a purely selfish point of view, if scientists say something and you know that they're all trying to prove each other wrong, you know the fact that they agree is like extra extra validity, exactly exactly. But imagine that, you know you want to check her for yourself. You want to be the scientist to disprove everybody. How could you do that? That was your question, And these days it's actually not that hard because of the ubiquity of basically high resolution cameras. Um, all you need to do is take a picture from high enough that you can see the curvature of the Earth. And to get high enough to like really see the curvature in an indisputable way, you need to be like thirty five forty forty feet up above the ground to see the curvature of the Earth. I guess, you know, um, it's not immediately clear what that means. So I guess if you go out really really far, like to the moon, you would definitely see the Earth is round, right, that's right, and but down here it looks flat. And so as you keep going up and out, you're going to see kind of more more of the rounded shape of the Earth. Exactly. So, as you imagine you're floating up from the Earth, right first it seems flat, and then you get higher and higher up, you're, like you know, at airplane levels, it still seems mostly flat. But as you zoom out you see it more as a planet, unless it's just a surface, right, You're zooming away from it to get more perspective on the overall shape of it, and then you can start to see the overall shape. You can see this curvature, and you know, above forty feet or so, it becomes pretty clear and you might be thinking, well, how do I get about forty feet? And the only way to do that through an airplane and those windows are weird and have curves and whatever, how do I really believe that? Well, all you need to do is send your phone up there, and folks have done this. You can. You can just build a weather balloon, which is basically just a big bag of helium or hydrogen, and attach a phone to it and it'll go up really really high, you know, eighty thou ft a hundred thousand feet basically up to near space. And high schoolers have done this. You know, you can google for pictures of it. Wait, what what do you do? Though? You do? You start like a FaceTime conversation and then send it up. There's no service up there, but you you know, you start recording and you send it up. And then the trick of course, is recovering it. Right where does it come down? So you just have it like take pictures. Every couple of seconds it goes up, the balloon, balloon pops, it falls down, and then you recover it and you get the pictures. Yeah, exactly. You have a little parachute, right, so it doesn't just plummet to earth and burn up and re entry and smash. And then you get the pictures and they're pretty fantastic pictures and it's very clear, and those pictures the curvature of the Earth, and they're gorgeous too. I mean, they're beautiful pictures. It wouldn't be like an effect of the fish eyelands or anything. No, absolutely not. I mean you can see it increasing with altitude, right, So it's not an artifact. So if you have an iPhone to spare and a weather balloon, you could you could discover that the Earth is round or or are they right? That's kind of the question that we post at the beginning, right, is the Earth actually round or not? That's right? And so we're pretty sure that is not flat. And if you look at pictures some space, you're like, okay, the Earth is round, right, it looks pretty round, But let's get precise, like do we really mean the Earth is like round? Is it a perfect sphere? Well, the key is that the Earth is spinning, right, and spinning things have extra complications, like if the Earth was not spinning it would, it would be perfectly round. You think, if the Earth is not spinning, would be much closer to perfectly round. Now, perfectly perfectly round is impossible. I mean, even if you like sanded the Earth down microscopically, there's no way to get all the atoms exactly the same distance from the center of the Earth, you know, and microscopic level level, perfectly round is impossible, even perfectly around it like the you know, the one mile level is pretty tough because you've got mountains, right, mountains and valleys and all sorts of stuff, um, and eventually those will you know, roll down into rubble. But then thanks to play technoics, you'll get new mountains. So the one two mile level, you know, the level even of like Mount Everest, it's pretty hard to have it be perfectly flat. But there's an even bigger effect, which is because the Earth is spinning, and so it's it's not perfectly symmetric anymore. Right, the Earth is round, it seems you might think like every direction should be the same, but it's not, because the Earth is spinning on a specific axis, and that spinning has this effect of pushing things away from that axis. The north, south axis. It's like if you're on a merry go round and somebody spins it, you feel this this effect that's trying to throw you off the merry go round, right, unless you're holding on. And so the same way if you if you spin up, if you take a planet that's not spinning and you spin it, it's gonna make it a little bit flatter and a little bit of sort of blobbier. Right, It's gonna make things further away from the center at the equator and a little closer in at the polls. Is it that it's pushing the stuff out in the on the equator outwards or is it that maybe the stuff on the equator doesn't feel as much gravity as the stuff in the north and South pole. No, it's an effect of the rotation. It's like if you take um, you know, pizza, you're spinning to take a pizza and you spin it, right, it gets bigger. Why does it get bigger? Right? Because it's the spinning. The spinning has this effective forces centrifugal force um that pushes things out and it's an artifact of the spinning. So like if if I'm feeling a little bit round and padded in my middle section here. It could be because I've been spinning too much. There are other explanations, but the has really simpler explanations. Too many banana cream pies, don't know. Yeah, but if you take something, you know, take like a ball of dough, and you spin it, then it will flatten, right, it will flatten, and it'll get um wider and in the middle and and uh and shorter on the top, oh, get shorter. And so that's what's happened to the Earth. That's what happened to Earth. Yeah, but you know, don't be alarmed as it formed or after it formed, do you know what I mean? Or like it's always been oblong, it's always been not round. That's a great question. It's definitely true as long as the Earth has been spinning. And I'm pretty sure the Earth has been spinning since it was formed, because it's been angular momentum um. But that must have changed, like for example, on the planet Uranus. Right, Urinus was hit by something really big that knocked it off at spinning in a different direction. That probably changed the shape of Urinus also, so that's a cool question. Yeah, yes, So if you change the spin of a planet, it will change its shape. And aren't their theories that say that our moon. We had a whole podcast about it, by the way, you guys can look at it, look for it in the arch in the archive. But it isn't there a theory that maybe we were hit by a giant rock and that's how the moon form, and so maybe our ax has also changed. Yeah, it could be. It could be we were spending a faster or slower before that massive collision and that would change the shape of the Earth. But you know, taking a moon size chunk also changes the shape of the Earth. So that was a big event in terms of shape of the Earth. Um. But people might be wondering out there, like how big an effect is this is, like, you know, because if you look at the pictures from the from space, the Earth looks pretty round. I mean maybe people haven't done like precise measurements of those photographs, but it does look pretty round, and it is pretty round. The answer is that the at the equator, the distance to the center is about thirteen miles more than it is at the polls. So the Earth is wider than it is taller by thirteen miles by thirteen miles and on one hand, that's a big difference in each direction. Each direction. Yeah, from radius. On one hand, that's a big difference because like some of the biggest features on Earth, like Mount Everest, are only a few miles high, so this is like two or three times bigger than that. Right. On the other hand, it's pretty tiny because you know, the radius of the Earth is thousands of miles, so it's a really pretty small effect. Like if you were holding the Earth in your hand, could you tell this difference if you like roll the Earth against a um along a smooth surface, when you notice it not rolling perfectly smoothly. I'm not sure. I think we would, we who live on the surface of Earth would notice it for sure. I'm trying to be that cosmic alien that's playing games with us, right, it's playing tricks. Imagine the galactus, your galactus just there. Um yeah, thanks. From from that point of view, I think it'd be pretty hard to tell. You know, I don't know. For example, like a very high quality poolball, you know, like billiard ball, Um, what's the level of sphericity of that and how does it compare to the Earth. That's a good question. Like a professional great billiard ball ball. Is it actually also even a sphere? Yeah, I don't even know. It might be more spherical mirath, or it might be spherical within the same tolerance, right, because thirteen miles is a small fraction of the radius of the Earth. And you're talking about kind of like the average distance to the center of the Earth, right, because there are sort of dips and valleys and oceans and stuff, but like the average that's right. Yeah, Well, I guess the question is why isn't it more oblong? You know what I mean? Like the Earth is speling pretty fast at least once a day that I know of, and that's a lot of earth to move around. Why is it it more like opal shaped? Yeah? Well that depends on sort of the internal strength of the earth. Right. If the Earth was made out of like, I don't know, cotton candy or something, and you spun it this fast, then probably a bunch of the cotton candy would get flung out in the space. Um, but it holds itself together, right, depends on the strength of the material. Like if the Earth was made out of pizza dough, we would be much flatter, that's right. And also there's gravity, right, Gravity does like to keep things together. So there's a bunch of things at play there. But you have the Earth is made out of pizza dough, it would have a different shape than it does today. Let's do that experience. Let's build a planet sized blob of pizza, just just to find out that's right. Let's make a piece of shop for the galactuses of the universe. Any listening billionaires, that's where you should send your funds, and then also send us into space to go eat some of this pizza. That's right. That's gonna take a lot of sauce. Al right. Well, so that that's the answer to the question. Is the Earth round? The answer is no, right, it's around dead right, round dish, but almost sort around. It's rounded, more rounded in the middle of the Earth is definitely not flat, but I mean it's definitely not flat, that's right, Like many of us, the Earth is definitely not flat. Definitely not flat. So not flat, oh my god, definitely not flat. Um, it's almost perfectly spherical. And that well. The other way you can just test that the Earth is round is just go off in one direction, right and just get on a plane and keep going. That's right, you know. The flat earthers have an answer to that. They say, well, the Earth is flat, um, and if you move in a circle, you're actually moving in a circle on that surface, which is crazy. It doesn't make any sense because if I see, there's an answer for you, well, but then you know, no, those answers make sense. Like if the Earth was flat, they put the north pole at the center and the South pole is like this wall of ice around the circular flat Earth. But if that were true, then that would really stretch out distances between stuff in the southern hemisphere because the sun the hemisphere would become huge. In the northern hemisphere would be compressed, and so you would definitely notice, like if you try to sail on a ship from you know, Chile to China, you would notice that it took you way longer than it should. Shipping captains and airplane pilots would definitely notice if the Earth was flat, all right, Well, and there's then then there's a whole totally different question, which is is space flat? Right? Like we could be a rounded Earth on a flat on flat space, right, or a rounded Earth on a round space. That's right, And I'm definitely a flat spacer. Were a round earther put a flat space. That's right, No space seems to be flat, and that's really weird, right, we don't understand why space is flat. For those of you who don't even know what that means, check out our podcast on the shape and size of space. Space is a weird, crazy thing and do all sorts of stuff you never imagined, including being curved or not being curved. And you might be able to send your iPhone out into the universe to find out that's right, leave the round Earth and go into flat space and learn some things. Um. But this is what I love about these questions, you know, they tell us so much about where we are in the world. And to discover that the Earth is round and it looks just like all those other planets must have been a huge shock to the people who discovered that, right, to understand something so deep about this, this situation we find ourselves in. Those are the wonderful moments in science, right when you get these flashes of insight and reveal something about the context of the human experience. Yeah, or like challenges everyday conceptions or ideas that you might have right exactly. The first guid figure out the Earth was round. Probably everybody scoffed at him and thought, oh, he's crazy. He's one of those round earthers. Right. The Internet, the Greek Internet, the Marble net, I think that a marble net back in Asian Greece. Yeah, they're all just talking under walkie talkies, posting trolling comments. It's too bad we lost. I mean, the Greeks developed the walkie talkie technology and then we lost in the Dark Ages. We had to reinvent it. Oh my gosh. Yeah, man, we had to reinvent the walkie talkie. Yeah, exactly. So much of human civilization was lost. Um no, but I think it's it's wonderful when we have those moments when we understand something deep about the human experience. All right, well, if you are a flat earther, um, we're sorry that this podcast disappointed you, And if you were around Earth, we're also sorry. Sorry that you're disappointed that the Earth is not round. But if you're a pizza ball earther, then congratulations, you're right, the Earth is a pizza ball. And if you were a flat there and you listen to this podcast and you were convinced link, congratulations for having an open mind. We'll hope you guys enjoyed that. Thank you for listening, See you next time. If you still have a question after listening to all these explanations, please drop us a line. We'd love to hear from you. You can find us at Facebook, Twitter, and Instagram at Daniel and Jorge That's one Word, or email us at Feedback at Daniel and Jorge dot com. Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of I Heart Radio. For more podcast from my Heart Radio, visit the i heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.