Alright my personal belief is that a 3d plane cannot be infinte because it has 3 defined dimensions. The 3d plane is the only one actually capable of being completely defined in size so the idea of it also being infinite doesn't sit well with me. Leading scientists will tell you that space has 10,11, or 26 dimensions but my argument against that is that you can make 3d models of everyone of their models (including the 26d one). If you can make a 3d model of something, I hate to break it to you but it is 3 dimensional. Stephen Hawking's idea of the graviton is the biggest pile of crap i've ever seen. Gravity is a result of mass, all mass not just specialized particles.

On to the big bang theory, It is completely impossible to begin with. If all the mass in the universe was in one spot to begin with, expansion would be completely impossible whether there was an explosion or not. Movement is only possible between 2 peices of mass. We can float around in space ships out in space because there's other bodies of mass out there making a very big curve for space. If all the mass was in one place, the cuve would be so sharp that you would not be able to expand outwards regardless of the power you were packing in that explosion. (some self promoting pat on the back bs) The distance between galaxies suggests that my theory of each galaxy being formed individually, instead of all coming from the same spot.

Imagine if you were the only thing in space: You would not be able to move (you wouldn't be able to survive but this helps understanding from the physics view). If there was a ball in your hand it would stay on your hand because movement outward away from your body is impossible because of inertia and the lack of space. That doesn't really make sense but once you have a single particle of mass in an unmeasureable void (this thing isn't big or small, it just IS because there's nothing to measure in it), the rules of that void completely change.