Henry Baker (10 June 2011) wanted to know about rigorous N-body simulations. Answer: You lose: There is no algorithm for simulating the N-body problem with rigorous results, as was proven by me in 1993, see paper #21 http://rangevoting.org/WarrenSmithPages/homepage/works.html Warren D. Smith: "Church's Thesis Meets the N-body Problem" ------- I also have papers about the computational complexity of other theoretical physics, for example I proved in paper #49 that N body problem in "garden variety quantum mechanics" is simulable (quantum mechanics is "easier" than classical mechanics?!) and in paper #58 that hydrodynamics is unsimulable, except that in this result I had to "cheat" by showing either that or 2 other alternatives which also would be devastating. It would be nice to go further to address, e.g. general relativity, standard model, but I put a lot of time into those with nothing coming out.