Where Did the Sun Go?

This morning when I was getting Roo and Love Bug ready to go and we were walking out the door, Roo asked me where the sun had gone.  It occurred to me that he, as far as he can remember, hasn't actually been outside in the morning when it's dark out.  I told him that the sun went night night and that when he and Love Bug go to bed time that the sun goes to bed time too.  My response was logical enough that he was satisfied with the answer.