Mathematics? It's all just life.

[Carbonated_Brains]

I worded that wrong, methinks.

What I mean to say is, the main variables you mentioned are a direct result of things like atom configurations and on which side of the fridge you store the marmalade, etc.

Each major variable is an amalagamation of the exact positions and states of trillions of tiny components, an error in measurement of any one of those components can propogate and exponentially increase.

So if some football player in Kansas jumps into the air right when you're trying to do your calculation, the infinitesimally small amount of force he exerts to jump, and the resultant gravitational pull which brings the two bodies (him and the earth) together again, resulting in a tiny change in acceleration of the Earth, resulting in a temporary change of initial conditions...that could be enough to throw off the calculation.

I doubt I'm explaining this any better than before.