Why Eratosthenes got it wrong.

Yep, Erathosthenes, that greek scholar who invented the leap year and measured the earth’s circumference, all in 200BC from Alexandria. I have discovered he systemically was set up to have errors based on his assumptions.

He was off by about 15%, and today I figured out part of why he was wrong.  The premise is Erathosthenes read in a book about a well in what is now the town of Aswan. He read this well cast no shadow on a particular day of the year. If you look at the image on wikipedia, it shows the suns rays directly overhead. This is impossible as Aswan is north of the Tropic of Capricorn by 50 miles. It would be approximate, but not truly directly overhead at solar noon on the summer solstice.  The sun can only be directly over head in the band south of the Tropic of Cancer to the Tropic of Capricorn.


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