Since the earth is rotating (see the “ Foucault Pendulum” experiment for a definite proof, if you are doubtful), the consistent oval-shadow it produces in each and every lunar eclipse proves that the earth is not only round but spherical-absolutely, utterly, beyond a shadow of a doubt not flat. This shadow is the planet’s, and it’s a great piece of round-Earth evidence.

It was quite a mystery to the ancient Greeks, though, and in their quest for knowledge, they came up with a few insightful observations that helped humanity figure out the shape of our planet.Īristotle (who made quite a lot of observations about the spherical nature of the Earth) noticed that during lunar eclipses (when the Earth’s orbit places it directly between the sun and the moon, creating a shadow in the process), the silhouette on the satellite’s surface is round. Now that humanity knows quite positively that the moon is not a piece of cheese or a playful god, the phenomena that accompany it (from its monthly cycles to lunar eclipses) are well-explained. On we go, to the top 10 ways to unequivocally, absolutely, positively prove the Earth isn’t flat. You don’t need to denounce all science and knowledge and believe in a conspiracy theory to enjoy some historical factoids about humanity’s quest for space. But the history of our species’ intellectual pursuit is important and interesting. He claims it’s ridiculous to even bother rebutting the Flat Earth Society-and I tend to agree. I’ve had a few ideas on how to do that, but got an interesting incentive when Phil Plait, The Bad Astronomer, wrote about the the Flat Earth Society. Humanity has known the world is not flat for a few millennia, and I’ve been meaning to show more methods on how to prove the Earth is round. This article was originally posted on her Smarter Than That blog in 2008 and has been lightly edited for Popular Science.

Moriel Schottlender is a software engineer at Wikimedia Foundation.

Eratosthenes flat earth