And that's not all (reposting, after logging in) (Score 1)

The Three-body problem in classical mechanics is known to not have any analytical solutions at all, let alone computable. Generalized, this means that as the number of material objects, moving under the action of their own gravitational fields, increases above 3, it becomes harder and harder to find out how they would be moving. That in no way implies that these bodies will become exasperated with computational complexity of their "n-body problem" and decide to simply fly apart.