Material Detail

The Round Earth and Christopher Columbus

The Round Earth and Christopher Columbus

This web page, created by David P. Stern, describes observations that show the earth is a sphere and the history of these observations. The round shape of the Earth may be inferred from the existence of a horizon at sea. Ancient Greeks deduced it from the shape of the Earth's shadow when the Moon is eclipsed and from stars visible only in southern countries. Eratosthenes accurately estimated the size of the Earth, but Columbus based his plans on an incorrect value, by which India would be much closer to Spain. This is part of a large web site, "From Stargazers to Starships" the presents physics concepts using space science and an historical perspective. Spanish, French, and Italian translations are available, as well as links to lesson plans for teachers.


  • User Rating
  • Comments
  • Learning Exercises
  • Bookmark Collections
  • Course ePortfolios
  • Accessibility Info

More about this material


Log in to participate in the discussions or sign up if you are not already a MERLOT member.