How did Aristole Prove the World was spherical?

Answer 1

He didn't. Gallileo proved the earth was round. Eratosthenes of Cyrene first put the motion forward and even calculated the diameter, but Nicholas Copernicus and Galileo Galilei first put the idea into the public eye.

Answer 2

Shreds of evidence kept piling up that seemed to suggest it:

1). As a ship sailed away from port, people left on shore lost sight of its hull first, then its deck, and finally the masts, just as would be expected if it were sailing away around a sphere.

2). Travelers reported that at the same time that the sun was directly overhead here in central Egypt, the sun had been lower in the sky in the places to which they had traveled, just as would be expected if they had traveled some distance around a sphere.

3). Over the space of many many years, historical records showed that every time there was a lunar eclipse, the edge of the earth's shadow on the moon was round ... regardless of what time of night it occurred, meaning regardless of which way the earth was turned. The sphere is the only shape that could cast a round-edged shadow no matter which way it was turned.

Answer 3

Aristotle never proves the Earth was spherical but he did observe "there are stars seen in Egypt and [...] Cyprus which are not seen in the northerly regions." Since this could only happen on a curved surface, he believed Earth was a sphere.

A few decades after Aristole around 240 BC, Eratosthenes (276-194 BC) accurately estimated Earth's circumference. He had heard that in Syene (now called Aswan) the Sun was directly overhead at the summer solstice whereas in Alexandria it still cast a shadow. Using the differing angles (1/50 of a circle) the shadows made as the basis of his trigonometric calculations he estimated a circumference of around 250,000 stades, it being 5000 stades between Alexandria and Syene.

Answer 4

Pythagorus discovered the Earth was a sphere when he witnessed a Solar eclipse. He realised that the Earths shadow was reflected onto the moon so it must have sphereical.