I have heared people say that the universe has no size or shape. My problem with this is how can the universe be expanding or how did it come from an infinitaly small spot(Big Bang). If it is expanding because an infinitly large object can not expand from an infinitly small point. I think that the universe is like a 4 dimensional sphere. So if you go in any direction in space and keep going eventualy you will be back at your original spot. becaue even though you are going straight in 3 dimensions but the 4th dimension is slowly curving. Kind of like the earth even though you are going straight in 2dimensions you are slowly curving in the 3rd dimension.