But the surface of a mobius strip is not infinite. It is indeed finite, But it is not bounded. The surface of a sphere (like earth) is finite but unbounded - there is no edge. Continuing in one direction on the surface of a mobius strip or the surface of a sphere will ultimately bring you back to where you started, yet you met no edge.
If the Big Bang was the start of our universe, then that was where time and space and matter/energy was created. There is no sense in asking what came before the big bang since there was no time until spacetime exapanded into existence. I believe our universe could be finite but unbounded (no edge) in the same manner as the surface of a sphere. Except that our universe (and the 4 dimensions we are aware of - spacetime, 3 spatial and 1 time dimension) may be the surface of a hypersphere for example. In my view, our universe does not have to be expanding Into Anything. Mainstream theory posits that space itself is expanding. Like the surface of a balloon being blown up. The surface of a balloon does not expand "Into" anything - the surface material (space) is simply stretching/expanding. Now we are not talking about the 3D sphere of the balloon expanding into surrounding 3D space, we are simply talking about the "surface" expanding. So, If our "surface", our universe, is expanding it does not need extra dimensions to expand into. A flat, 2D piece of rubber can be stretched or expanded without needing a 3rd dimension. And it can also be stretched/expanded if that flat piece of rubber becomes curved back on itself to form the surface of a sphere. We are not talking about forming a sphere - we are talking about changing the geometry of the rubber to form the "Surface" of what we, in our 3D world, would call a sphere.
Whew! Hope I haven't lost myself. That's just my 2 cents and admittedly most probably flawed idea of things.
