How did Eratosthenes measure the size of the earth?
1 Answer
Mar 14, 2016
From the shadow angle of a tower in Alexandria at Summer Solstice noon and identifying the angle it with the angle subtended by the Earth's arc between Alexandria and Syene, in the year 240 BC.
Explanation:
The angle identified was about 360/5 = 72 deg.
The circumference was approximated by Eratosthenes, with an error of about 1% against the current precision.
History speaks of computational ability in humans, over millenniums.
I am glad that the questioner brought this to Socratic notice.
My reference: www.windows2.universetoday.org/.../eratosthenes-calc-earth-size.html
