How Eratosthenes Estimated the Circumference of the Earth Over 2,000 Years Ago

Posted on August 25, 2016  Comments (4)

In this video Carl Sagan explains how Greek astronomer Eratosthenes, in 200 BC, was able to deduce and calculate the earth was a sphere about 40,000 km in circumference.

It is wonderful to see how a bit of thought and curiosity have lead mankind to learn so much.

Related: How do Plants Grow Into the Sunlight?Why is it Colder at Higher Elevations?Great Webcast Explaining the Digestive SystemBiology: How Wounds to Our Skin Heal