1 Another fact that breaks the flat Earthers' minds: With a round Earth, we are able to perfectly predict the time of sunrise, sunset and the movement of the stars and planets. Flat Earthers cannot do any of this. posted 229 days ago by Eisenhorn 229 days ago by Eisenhorn +9 / -10 Flat Earth can predict and calculate nothing. 59 comments share 59 comments share save hide report block hide replies
This is much like the question you asked regarding the procedure you supplied that you thought measured the curvature of water when it didn't.
What eratosthenes (his slave, actually), apocryphally, measured was the angle/length of shadows. Obviously.
What he calculated was the circumference of the world IF it was spherical, sunlight rays are always parallel, and a few other unvalidated assumptions.
If the world is not spherical and/or any of the other underlying assumptions were wrong then what he calculated was just nonsense.