Hi, we're here from curiosity.com to help you get smarter in just a few minutes.

I'm Cody Gough.

And I'm Ashley Hamer.

Today you learn about how the ancient Greeks knew the earth was round, why being passionate about your job can backfire,

and why you shouldn't worry if you find a hair in your food.

What satisfy some curiosity.

Did you know that even the ancient Greeks

knew the earth was round? Yeah, this is actually a thing we've been

aware of for more than 2,000 years. And the story of how they knew it was round is a

good one, so let's get into it. The philosopher and mathematician Pythagoras is credited as the first to propose a spherical earth back in 500 BC, though he did so on aesthetic grounds. He believed the sphere was the most perfect shape. A century later, the philosopher

Plato suggested the same thing, which boosted the idea's popularity. But when it comes to

proving the Earth is round, Aristotle was the first Greek

philosopher to put his money where his mouth was. When he was writing his book

On the Heavens in 350 BC, he laid out several pieces of evidence for the Earth having a spherical shape.

For one thing, he pointed out, you can see the shadow of the Earth on the Moon during a lunar

eclipse, and since that shadow is always round regardless of where the Earth is in its rotation,

you know the Earth is a sphere.

For another thing, the stars are in different positions depending on where you are on Earth. There were stars in Egypt that couldn't be seen in Cyprus hundreds of miles away.

He wrote that that proved, quote, not only that the Earth is circular in shape, but also that it is a sphere of no great size, for otherwise

the effect of so slight a change of place would not be quickly apparent."

Later, another scholar named Eratosthenes did Aristotle one better.

He didn't just prove the Earth was a sphere.

...