Explanation: Eratosthenes was a Greek polymath who lived in North Africa in the 3rd century BCE. An immensely accomplished and intelligent man, one of his most resounding achievements was to measure the size of the earth. While Greek philosophy already considered the world to be spherical, Eratosthenes managed to use extremely simple tools, with an understanding of mathematical principles, light, shadow, and geometry, to calculate the size of the earth to within ~10% of its actual value, as measured by modern tools!

Flat Earther lunatics in the modern day have attempted to re-perform his experiment, expecting a different result from the OBVIOUS flatness of the earth. It never works out for them. Curiously, it rarely changes their minds, either.

i think there was a greek(?) guy who made a map of all known locations on earth in the 3rd century AD, and in the preamble he stated that the earth was a sphere, and he almost got the diameter correctly, he only estimated it to be 25% less than it actually is (same order of magnitude though).

1200 years later columbus read that stuff and thought "huh, okay, based on this diameter i can sail to india no problem". even though it was known at the time that the diameter would have to be higher, columbus kinda willfully ignored it (wishful thinking). and got lucky.

Well if you won't accept the evidence of two sticks and math, the alternative for me is to shove the sticks up your ass.

In my head, I only ever hear Erastothones’ name in Carl Sagan’s voice as he recounts the story in the original Cosmos series. ❤️