Aristotle's hypothesis was that:

the Sun lay at the center of the planet orbits.

the Moon orbited the Earth.

lunar eclipses were created by our shadow.

only a spherical Earth would always cast a circular shadow on the Moon.

lunar eclipses would have to happen every full moon.

only a spherical Earth would always cast a circular shadow on the Moon.

Explanation:

Around 340 B. C., Aristotle states that the Earth is round, not flat, and gives three arguments in favor of this thesis:

- In lunar eclipses it is always observed that the shadow of the Earth on the Moon is shaped like an arc of circumference.

- The difference in the apparent position of the Polar star between Greece and Egypt, which even allows it to calculate the size of the Earth in 400,000 stadiums, approximately 80000 km. of circumference (double the actual size).

- In the sea when a ship appears on the horizon the sails are seen first and then the ship's hull.

It also states that the Earth is still and the Sun, the Moon, the planets and the stars move in circular orbits and with uniform velocity around it, since the circular movement, being the most perfect that exists, is the one that should rule the heavens.