These days everybody knows the earth is round. This idea wasn’t always commonly accepted. It wasn’t even an idea to begin with. Most believe that the Western civilization started progressing intellectually only after the dark ages. The Middle Ages were actualy an intulectual downfall. Most of our knowlegde has gone lost throughout this period of destruction, death and disease.
Today there are still numerous misconceptions about the earth being round. We always asumed that Galileo Galilei discovered that the earth is round in 1610. Actualy this discovery was made about 1800 years earlier by a Greek high intulectual, named Eratosthenes.
Ersatosthenes learned of an interesting phenomenon in the town of Cyrene, in southern Egypt. At precisely noon at every 21th of June, which was the longest day of the year, the sun stood directly overhead in Cyrene. Vertical pillars would cast no shadow and the well would be elumminated al the way to the bottom. This never happend in Alexandria several kilometres to the North. Ersatosthenes believed that this was due to the curveture of the earth. He could use this to measure the size of the earth.
By his calculations the circumference of the earth was about 39.500 km. Today we know by various scientific calculations that the actual circumference of the earth is 40.070 km. The estimation of Eratosthenes is remarkably accurate, knowing that he didn’t have the ability to use precise measuring instruments.