So, the calculations we came up with for the big bang theory?

Is it based on speed divergence alone, essentially in one direction? There isn't any defined central point, right? Is it thought to be that somewhere on the other side of the universe, there is a point in space moving in the exact opposite direction than space is moving where we are? If the theory of exploding from a single point is true, wouldn't it make sense that space is expanding in all directions from that point? If not, couldn't we just say that we are measuring a small blip of time in space that could be moving at different velocities for any given reasons that we haven't yet discovered? I've just been thinking about this in the sense that no central point from which the universe expands has been defined, and that something else could be at play. I obviously don't know much about theoretical astrophysics, so if you could explain this so it makes sense, that would be great.