East central Iowa | If you want to see the video of Sagan explaining how the ancient Greeks discovered the earth was round and even correctly calculated it's circumference this is it:https://youtu.be/8hZl3arO7SY
However I don't understand one little part of the explanation. Given that the two locations were 800 kilometers apart and they didn't have TV, radio, or telephones, how did he determine that the two locations had different length shadows at the same time? |
so, how did he know the shadows were different?
