Wednesday, 28 February, 2001
Earthlink's Advertisement Rewrites History
EarthLink has recently been running television advertisements that say (I'm paraphrasing) "People used to think the world was flat. Then along came Magellan, who set sail in one direction and came back the other way." The ad ends with the line: "You can settle for someone else's version of the world. Or you can bravely embark on a journey of your own."
The first "journey" I'd suggest to people who sign up with EarthLink is some historical research. They'll find that Magellan didn't come back. He was killed in the Philippine islands. Any 7th grader knows that. If they dig a little further they'll find that the ancient Greeks knew the earth was round. In Aristotle's time (350 B.C.) the estimate of the Earth's circumference was about 40,000 miles—about 60% larger than the real value. About 80 years later, Eratosthenes used the technique described here to calculate a value of about 24,000 miles, which is very nearly correct.
History credits Magellan (and one of his captains, Elcano) with supplying the first "practical proof" that the Earth is round. By that reasoning, I guess we don't yet have practical proof that the Earth circles the sun.