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Untrue -- we've been simulating particle trajectories over large areas for nuclear weapons for decades now on supercomputers



Weapons simulations *never* follow individual particle trajectories and never have. There are far too many particles and thing happen much too fast. Instead it's simulated very finely as a (strange) fluid, in as much detail as possible, but orders of magnitude beyond particle-level.

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and also to a lesser (and less serious) degree, weather. Climate simulations exist -- you don't need to simulate to infinite depth to get approximate results.



Weather prediction is *chaotic*. See work of Edward Lorenz. Since it is chaotic you really do need to simulate to fine detail to get results of any precision (or accuracy depending on the simulation.

Lorenz wrote a paper on this topic using one my favorite titles of all time for a serious academic paper: Predictability: Does the Flap of a Butterfly's Wings in Brazil Set Off a Tornado in Texas?"
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