there are periods of regular day/night cycles and polar day as well. what doesn't make sense to me about the flat earth is the fact that antarctica and the arctic are usually opposite in the day/night cycle, but looking at a flat earth model, i see that it should be completely different from that. if the sun is in a rotation above the earth, then the arctic should always be sunny and only certain parts of the arctic should be dark/light. that doesn't make sense, because antarctica is usually entirely day or night. i think the time zone is pretty much universal there. and with the arctic, it has a day/night cycle, a sophisticated one, but it isn't always sunny or dark, and the flat earth model implies that it would be.