Can the space (or else measurable) be actually infinite?

[Alex K]

Yea, I'm not saying it's true, but it is a theoretical possibility that doesn't contradict any observations...

But why reduce 3d spaces to 2d-manifolds? Can it not be 3d modeled in a way that does not contradict observation?

The 2d was just for simplicity, of course you would do it in 3d in reality, e.g. the cube with opposite faces identified.

[Arkilogue]

But space is not cubic...? Sorry, I'm not trying to be deliberately obtuse.

[Alex K]

But space is not cubic...? Sorry, I'm not trying to be deliberately obtuse.

Space *might* have the topology of a three-dimensional torus, and one way to construct this mathematically is to start with a cube and then identify opposing faces as identical as if glued together, i.e. you go out one you come in the other. This is impossible to visualize as a shape because you'd need 4 or 5 dimensions for that, just like you need three dimensions to show a 2-dimensional torus surface.