In Reply to: Falling off the face of the earth posted by RRC on October 02, 2008 at 05:37:
: : : : What is the origin and meaning of the phrase "falling off the face of the earth"?
: : : A guess. Some people used to think the world was flat, a plane, and that a ship could literally sail to the edge and fall off. (
: : : https://en.wikipedia.org/wiki/Flat_Earth ) So the phrase is used when someone hasn't been seen for a while -- has dropped out of sight.
: : That's a bit of a myth. No one has ever (a few of the the very strange 'Flat Earth Society' members aside)really believed the earth is flat. In the 4th Century BC Aristotle was drawing the earth as a sphere for example.
: : And anyone who has ever been on a ship would know that the world is not flat.
: : DFG
: It is a myth that all people in the Middle Ages believed the Earth was flat, but "no one" and "ever" is an incredible overstatement.
The Wikipedia article covers all of the above.