At the same time, just south of Alexandria in Syene, no shadows were being cast by the Sun.
Eratosthenes determined the planet must be curved if the Sun was casting its light at the same angle but shadows were only present in one location.
The Earth’s shape can be easily proven with very simple experiments.
If you look at a ship sailing off in the horizon, it will not grow smaller and smaller until it disappears.
Instead, you will see it sink below the horizon ... Read even more
