ERATOSTHENES MEASURED THE EARTH OVER 2,200 YEARS AGO#History #Science #AncientGreece

Added: 2026-05-17

[00:00:00]More than 2,200 years ago, Eratosthenes set out to measure the exact size of the Earth. He knew that in Aswan, the sun cast no shadow at noon on the summer solstice, but on that same day in Alexandria, a vertical column did cast a shadow. He measured the angle >> [music] >> and found that it was about 7.2°.

[00:00:21]That angle represented 1/50 of a full circle. He multiplied [music] the distance between the two cities by 50 and calculated the size of the Earth with astonishing accuracy.