Lisa Peterson --- how do you conceive of the edge?  Flat earthers don't have all the answers, they don't pretend to!  They are STUDYING the topic, and have found that the earth CANNOT AT ALL BE A SPINNING BALL.  This is easily and thoroughly proven, in endless ways (see the videos and books and blogs etc to find the proofs and research).  As to the edge, many of the flat earth working models/theories involve an ice wall "at the edge", so there really IS no edge to fall off of.  The waters are contained (thus the oceans lay "flat") by the ice walls of Antartica.  Search youtube "flat earth edge ice walls" if you want to explore this.  No scientific study has show the spin of the earth.  It is stationary.  No curve of the BALL/SPHERE earth has been observed.  Nothing works on a ball earth:  even our eyes, ears, bodies.  Humans don't build structures "to the ball", we don't travel "to the ball".  It all sounds bat crud crazy, I know.  I thought so too.  But I decided to look into it.  :-)