the 2nd question is easy to recreate, in your own living room.
take a lamp with a bare lightbulb and position it a few feet above a floor.
Turn off all the lights. see that the floor is illuminated in a circle of light (similar to our sphercial sun)
now imagine the whole living room is the giant disc. If possible walk in a circle around the room, see how this circle of light moves with you. This is what cause day, night, time zones...ect.