Carl Sagan explained the thought process of the ancient Greek scientist Eratosthenes, who determined the circumference of the Earth.

A look at the evidence for the Earth being round or spherical. Aristotle’s reasoning is explained. The evidence includes a ship’s hull disappearing first over the horizon, the stars ...

A look at the evidence for the Earth being round or spherical. Aristotle’s reasoning is explained. The evidence includes a ship’s hull disappearing first over the horizon, the stars ...