There is a group at the U. of Tokyo which developed a "GRAPE" ("gravity pipeline", I'm glad you asked) processor for doing massively parallel processing on these types of problems. See Supercomputer Conference from 2002 for more details (http://www.supercomp.org/sc2002/). They simulated 1.8 million particles/protoplanets in the vicinity of Jupiter, Uranus & Neptune to try to understand where comets come from. Apparently, large-scale simulations of this sort are on the "cutting edge" of parallel processing, because there are no known good methods for doing such large scale simulations. Barnes-Hut, Greengard, etc., are good theoretical results, but don't parallelize readily. There are quite a few PhD theses available in this area. At 06:12 PM 6/27/03 EDT, asimovd@aol.com wrote:

I am curious whether anyone has done large-scale simulations of point masses in 3-space with random initial positions and velocities, under Newtonian mechanics & gravity.

I'm especially curious whether that's enough for galaxy-shaped objects to appear.

--Dan