1. The Greek mathematician, Eratosthenes, had accurately deduced that the world was approximately 25, 000 miles in diameter.

2. Eratosthenes calculated the distance to the sun in 200BC, having already deduced the circumference of the Earth.

3. It was there, 18 centuries before the Copernican revolution, that Aristarchus posited a heliocentric solar system and Eratosthenes calculated the circumference of the Earth.

4. BC - Trojan War: Troy was sacked and burned, according to the calculations of Eratosthenes.

5. The best of the early measurements of the earth's circumference was made by Eratosthenes.