N-body simulations
An N-body simulation computes how a group of bodies move when every body pulls every other body by gravity, like the planets of a solar system, the stars of a star cluster or the stars of colliding galaxies. With a few bodies, every pull can be computed exactly, and three bodies are already enough for chaos. With thousands of bodies, computing every pair becomes too slow, so the Barnes-Hut algorithm groups distant bodies in a tree, and the Fast Multipole Method goes further by grouping both sides of the interaction. The graphics card can also compute every pair directly for hundreds of thousands of bodies, with no approximation.
Below you can find all online tools with the tag: N-body simulations
