
Eratosthenes
Happy Columbus Day to those in the United States and Happy Thanksgiving to those in Canada.
On Columbus Day, it seems appropriate to consider the role of error in discovery. While many of us were taught in school that Columbus proved that the world was round, that is a rather shoddy myth. The ancient Greeks understood that the world was round by the 6 century BCE. Indeed the Libyan mathematician, Eratosthenes, calculated the circumference of the globe to be 250,000 stadia. Let’s put aside the fact that no one agrees on the length of a stadia, literally the length of a stadium. If one uses the Egyptian stadia, Eratosthenes’ estimate of 25,000 miles came within just 100 miles over the actual circumference at the equator (24,901 miles). Eratosthenes, in fact, made several mathematical errors but they cancelled out.
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