So the way time zones work is because the sun can only hit one side of the earth at a time. O <-sun | <-sunlight I guess? o <-earth This makes it dark one one side and light on the other. With a flat earth, we'd have O <-sun | <-sunlight __ <- a flat earth? Which would make it day all over at one time, then night all over at another time, instead of different times like there are. EXPLAIN THIS, FLAT EARTHERS P.S. Excuse my crappy diagrams. I don't draw very well. Update: these responses are hilarious. Also, I'm kinda trending. Kinda. Not really. A little bit.