2. One assumption that Eratosthenes made was that the earth was a perfect sphere. What are 5 other assumptions critical to this calculation?
Eratosthenes was a Greek mathematician who lived 276-194 BC. At summer solstice he waited until noon, when the sun was directly overhead in Aswan. He placed a gnomon (basically a stick) at the bottom of the well at 90° to the ground, and noticed that it cast no shadow. Then at the same time he had others place a gnomon in Alexandria. He found that the tip of the gnomon made an angle of 7° to the edge of the shadow, where the gnomon was again at 90° with the ground. Based on records at the Library of Alexandria, he knew that the distance from Aswan to Alexandria was 5,000 stadia.
2. One assumption that Eratosthenes made was that the earth was a perfect sphere. What are...
Eratosthenes was a Greek mathematician who lived 276-194 BC. At summer solstice he waited until noon, when the sun was directly overhead in Aswan. He placed a gnomon (basically a stick) at the bottom of the well at 90° to the ground, and noticed that it cast no shadow. Then at the same time he had others place a gnomon in Alexandria. He found that the tip of the gnomon made an angle of 7° to the edge of the...
Did Eratosthenes really do the measurement? Because the Great Library at Alexandria was an amazing firetrap (wood shelves, papyrus scrolls, etc.), it burned several times and many of the early Greek manuscripts were lost. All of the descriptions that we have of Eratosthenes are second-hand in what were essentially astronomy textbooks. As we will se later, the ancient Greeks often did thought experiments but did not always do the actual experiments. My opinion is that Eratosthenes las the right man...