Neil Tyson Demonstrates Absurdity of "Flat Earth"

so tell me Mele is the earth flat we have video from space of the rotating spherical earth the earth is round thank you for joining us on this episode [Music] what's what's odd is they're people who think earth is flat right but recognize that the moon is round Mercury Venus Mars Jupiter Saturn Uranus Neptune and the Sun are all spheres but earth is flat that's not something doesn't square that's a job right okay plus in my latest book hmm your latest book is called astrophysics for people in a hurry well I swear we didn't plant the book I have an entire chapter titled on being round and it's an exploration of how all the laws of physics and the accounting of energy as processes unfold in the universe how that conspire to make things round so it favors the sphere favors a sphere yes and if something is not a sphere it's a little bit flattened you can ask what's landed and you find out oh it's rotating real fast right so then it gets a little flattened because of that right and so almost everything in the universe is either spheres or slight distortions of a sphere for some other thing that's happening to it I mean we can just see how the the universe favor spheres so its nature right basic nature universe it is fairness to the people who want a flatter yes let's be fair to those in Columbus's day there was surely a flat earth contingent yes columbus predates the era of experimental checking of any idea you might have not a lot of peer-reviewed study found just like just say whatever yourself you know what I believe that elephant poop will cure cancer there you go that's right wrote a paper about it like to read it here it is good right right so it was a tool to Francis Bacon Galileo 1600s where the idea that if you're gonna say something and you think what you're saying is true then no matter how obvious you think it is that it's true you should still test it gotcha there could be something fooling you in one way or another so if you want to say earth is flat then for example lunar eclipses what's a lunar eclipse if your face is the brilliant Sun thank you and this is Earth and the moon is over here the Sun is always casting Earth's shadow into space it's always there no matter what right obviously okay it's such a shadow it's a shadow the moon is shining on blackness yeah a shadow in darkest shadow and so so the moon occasionally passes through that shadow and if you see the shape of Earth's shadow on the moon it is always round always round if earth were flat sometimes you get like a flat shadow all right we've never seen a flat shadow right in fact it is a segment of a arc of a circle no matter the orientation of the moon and the Sun and the only thing that makes a perfectly circular shadow would be something that's perfectly circular perfectly spherical yes so the only thing that makes a perfect circle shadow every single time is a perfect sphere right okay no matter what angle and where as a disc it would only make a perfect circle if you lined it that way and then they have to look at the face of the disc in order to get the circle Greeks knew this right all the lunar eclipses had they said oh my gosh we must be in around earth this is thousands of years before Columbus exactly so now if the earth is round how big is earth you might want to check for that there's a famous experiment conducted by Eratosthenes Tufton Eve ever touched the knees the two cities in the old world and one of them they knew that at 12:00 noon on a particular day of the year that the Sun was directly overhead and you can see the bottom of a well okay you don't run around looking at the bottoms of wells no do you net because the light doesn't take it's just that doesn't get down it doesn't get down it how can we use this observation to see if Earth's surface is curved we needed another well turns out we can't see the bottom of both wells at the same time what might explain this they're two possible explanations first we could have a flat earth with the Sun that's small and close by so that the light hits the second well at an angle or a second we could have a curved earth with a Sun that's big and far away so that all the light comes in parallel but only one well at a time is lit all the way to the bottom turns out with just two wells there's enough wiggle room for both explanations to fit our observations Eratosthenes only had two wells but what if he had added a third with a third well it doesn't matter where the Sun is no flat earth model can explain the angles of all three shadows but the spherical model explains it all all three angles with ease and to do this experiment you got to measure the angles Greeks had the angles yeah okay in fact geometry translates to earth measurement so one last thing which should be obvious okay if you pay attention and think about it if you send a ship straight to the horizon eventually it begins to disappear until it's no longer visible beyond your horizon right and you should ask yourself what kind of surface would produce that result if it's con Ocean has a ramp just like going down seafarers knew this right and so what however flat they would have imagined the earth to be they couldn't they couldn't have accepted to be completely flat because otherwise you would never not see the ship okay also if I just tell you chuck walk due east okay right and don't ever stop right I just turn around my chair and face this way and eventually you're gonna come back right and you'll probably be about a hundred and fifty years old cuz I'm no Forrest Gump that is that long that would take me to run the earth for me the fact that there's a rise of flat earthers there's evidence of two things okay long one we live in a country that protects free speech that's actually kind of Awesome and two we live in a country where they failed education system whoo that one hurt our system needs to train you not only what to know but how to think about information and knowledge and and and and evidence if we don't have that kind of training you'd run around believe anything anything anything and if you're interested in learning more about the earth the Sun and how the fact that we're rolling through space at what do I what is it 17,000 miles per hour is that what we're going to pull that number out of your you know what I pulled it from so you should consider all of this and consider chucking out brilliant whether you are an adamant defender of the Earth's curves mmm-hmm or a professional scientist or a lifelong learner brilliant helps you master concepts of math science and engineering through solving fun challenging problems and you can sign up for free to get access to weekly challenges and as a bonus to Startalk viewers anyone up to the 19th prime number that goes to brilliant dot org slash star talk will get 20% off the annual subscription which helps you think like a scientist through god of course material and the ability to track progress with stats and extra practice if you like what you see and you want to watch more videos from star talk hit the subscribe our and click the little button that gets you notifications every time that we put up a video and don't forget to like and comment below with the topic of your own that you've been dying to get to the bottom of all right so hey for those of you who are flat earthers we say it's ok as long as you don't run NASA and for those of you who are Greek philosophers and mathematicians Neil will tell you what they would tell you which would be I don't know Greek but if you could translate ancient Greek into English they would say keep looking up [Music]

Channel: StarTalk

Views: 4,622,672

Rating: 4.7484579 out of 5

Keywords: earth, flat earth, round, neil degrasse tyson, chuck nice, comedian, comic, science, podcast, startalk, startalk radio, brilliant

Id: hLPPE3_DVCw

Length: 9min 0sec (540 seconds)

Published: Fri Mar 09 2018

Reddit Comments

[u/[deleted]]

I'm an avid listener of StarTalk and I've never seen Chuck Nice until now. I expected him to be older.

[u/Truthoverdogma]

This video gas turned me into an unpaid shill for Brilliant.org, the website and app are amazing

[u/Jungle_jooce]

If we stopped giving so much attention to flat-earthers they would go away.