Did Columbus Prove the World was Round?

Ancient Greek Astronomy and Cosmology | Modeling the Cosmos | Articles and Essays | Finding Our Place in the Cosmos: From Galileo to Sagan and Beyond | Digital Collections 

Selin, Helaine, ed. Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures. Berlin: Springer, 2008. Print.

Who figured out the Earth is round? | StarChild Question of the Month | NASA  

A very short history of astronomy - The Earth - MATC Ecampus 

Christopher Columbus Never Set Out to Prove the Earth was Round | HISTORY 

Myth of the Flat Earth - Jeffery Burton Russell 

(8) The Round Earth and Christopher Columbus - NASA's Polar, Wind and Geotail Site 

Tzeela: Hi I'm Tzeela and I'm 16

Rina: Hi I'm Rina and I'm 14

Dalia: Hey, I'm Dalia and I'm 10

All: And this is Things You Thought You Knew About History! 

Tzeela: Where we tell you the real story behind historical misconceptions.

Rina: You’ve probably heard that people a long time ago thought the world was flat. You know, Columbus wanted to prove it was round by traveling all around the world to get to the Indies in the east. You may have even heard that people refused because they were scared he’d fall off the edge of the earth. That’s all true, right?

Tzeela: Not exactly. This is what really happened: 

Columbus: Your highness I would like to propose a plan to you and your council.

King John II of Portugal: Yes Columbus, I’ve heard you've found a faster way to the Indies, one that doesn’t require going all the way around Africa.

Columbus: That’s right King John II! We will sail west, around the world, all the way to the Indies. I believe it won’t be such a long journey, just 3,000 nautical miles.  Once we are there we can get spices and so much more and I- I mean you- will be rich!

King John II of Portugal: That would be quite a feat if it were true. Councilmen, what do you think?

Council: That’s absurd! It’ll take way longer! Your Highness, I suggest we don’t use our money on this. It would be a waste. Columbus has underestimated the length of the trip and I just don’t think his plan makes sense, I don’t believe it’ll be possible. 

King John II of Portugal: I’m sorry Columbus but we don’t want to risk losing this much money on a nearly impossible journey.

Columbus: Fine, good day your highness. I will try somewhere else:

Tzeela: So then he went to Spain and at first there too they rejected his plan. They also didn’t oppose it because they thought the world was flat but because they couldn’t finance the journey and because they didn’t want to anger the Portuguese who they just recently settled a dispute with. Eventually, the Spanish would end up agreeing and would be the ones to sponsor Columbus's journey to the Americans.

Columbus: King Ferdinand I know you’ve been refusing my plan for years but now I have funding from my supporters and Luis de Santangel, the royal treasurer.

King Ferdinand of Spain: I see…

Queen Isabella of Spain: I think we should do it. This is such an opportunity! A faster, cheaper way to the Indies! Think about it Ferdinand dear.

Ferdinand: Well I suppose you’re right. And my council agrees? Yes. Alright Columbus, we approve.

Columbus: Woohoo, I did! Oh yeah, go me! I mean thank you your highness I won’t disappoint.

Dalia: Wait, So if they already knew during Columbus’s time that the world was round who figured it out? And when?

Rina: A Greek astronomer and mathematician named Pythagoras was the first one who concluded that the Earth was spherical when he noticed that the Moon was. He could tell by the way the Moon reflects sunlight. There is always a curve between the dark and light sides of the Moon never a straight line, this happens on spheres. Knowing the Moon was round, he thought all heavenly bodies and the Earth were too. This was around 500 B.C.E.

Dalia: Well soon they had more proof, when a little while after that Anaxagoras and Empedocles, other Greek astronomers, studied the shadow Earth cast on the Moon during a lunar eclipse. The shadow was always curved, proving the Earth was a sphere. 

In about 350 B.C.E. Aristotle used the pattern of the stars to once again prove the Earth’s shape, but by his time it was already a well-known fact.

Rina: In 240 B.C.E. a Greek mathematician Eratosthenes calculated the polar circumference, the measurement around the Earth through the poles, and his result was relatively accurate 

So they clearly knew that earth was round, and they also knew more than that 

Tzeela: So the Greeks knew the earth was a sphere but what about everyone else?

Dalia: Well the Romans proposed the idea of traveling west to get to China long before Columbus’s time but never actually did it. 

And some of the foundations for Islamic astronomy were adopted from the Greeks so the Muslims also knew the world was round

Rina: Many Indians also believed the Earth was round.

We know this because we have descriptions of armillary spheres, a special type of globe. These were written between 500 and 1300 CE. In these descriptions it describes the earth as a sphere.

However, some people a long time actually did think the Earth was flat.

The Chinese astronomers had a theory that the earth was flat and the sky formed a dome over the top

Dalia: But then why do people think that around Columbus’s time people thought the world was flat if its clearly not true? Where did this myth start?

Rina: It can be traced back to two different authors who each came up with this story by themselves 

One was a French author Antoine-Jean Letronne who wrote that medieval Christians thought the Earth was flat in his book On the Cosmographical Ideas of the Church Fathers. This may have been anti-Christian or anti-religious. 

Tzeela: The other was an American author Washington Irving who wrote fantasized or exaggerated history stories and used this story to make Columbus seem more daring, heroic, and forward-thinking.

Rina: Here are some quick cool ways you can tell the earth is actually round 

Dalia: Well you can watch a  lunar eclipse like the Greek astronomers Anaxagoras and Empedocles did. If the world was flat the Earth's shadow would be a straight line but it's not. 

Rina: Or measure the shadow of two objects of the same height in locations 100 feet away from one another. If Earth was flat, these shadows would be the same length, but they aren’t since the curvature of the earth makes different parts of Earth have shadow hit at different angles even at the same time of day.

Tzeela: You can also look at the pictures NASA has of the Earth from space. I think the pictures are super cool you should definitely check this out!

Rina: You can even see that the earth is round by watching a ship sail off to sea. If you watch the mast and flag of the ship as it sails into the distance it doesn’t fade into the horizon like it would if the earth is round, rather it looks like it is sinking.

We found a video of this and it wasn't super clear but we definitely saw it. 

Dalia: And it was super cool.

Tzeela: We hope you enjoyed learning all about when we discovered the earth is round. Be sure to subscribe to the podcast so you can see when our next episode comes out. We will hopefully have a new episode every month. Also, you can email us at thingsyouthoughtyouknewhistory@gmail.com. Boy, that was a mouth full!  And let us know what you liked, didn't like, and if there are any topics you want to know more about or changes you want us to make. We want and love your feedback so we can improve and make the podcast better for YOU. Please feel free to email us with any feedback or if you have a question about anything we mentioned! 

Dalia: Talk to you in a month! 

Rina: I hear it's going to be really interesting and maybe related to... Mickey Mouse!