Ronn K. answered • 06/15/20
Staff member of the Department of Physics & Astronomy at WKU
Though we now know the Earth is spherical in shape, for a long time many people were convinced it was flat. It just looked like it. The size of a human being, compared to the Earth’s radius, is miniscule. Surprisingly, however, there are some who still insist to this day that the Earth is flat. Type “flat Earth theory” into a search engine if you want a good laugh.
All that having been said, there is much evidence that the Earth is a sphere. By now we have seen it from space. Our satellites and our astronauts have seen and photographed it. And it’s a sphere. Additionally, our high-powered telescopes have viewed other planets in our Solar System, and they are all spheres. It seems that by the laws of physics, once a spinning body achieves a certain size, the momentum of spinning forces it into the shape of a sphere.
But even the ancients suspected it was not flat. Observing lunar eclipses, they noted that the Earth’s shadow as it began to spread across the Moon was curved.
They noted that as ships sailed off across the horizon the last thing that disappeared was the top of the mast. If the Earth were flat, the entire ship would remain in view, and just get smaller and smaller. But if the Earth were round, then the ship’s hull would dip below the horizon first. And that is what they saw.
If you travel to a different latitude, you will notice that the star patterns change. If, for instance, you moved across the surface of a flat Earth, you would always be able to see the North Star, Polaris. However, such is not the case. When you travel below the equator, Polaris is no longer visible.
