Matter and Dark matter particles: What forcefields/addons should I use?

I’ve been trying to make something to simulate the big bang with particle systems for a while now, but I constantly find problems, such as the universe collapsing in on itself, galaxys failing to form, and having it give very even distributions of particles.

I have realized that the one, perfect solution would be dark matter/energy, but that would require forcefield systems which I have no idea how to create, and may be impossible without addons. What I need is something that simulates the properties of dark matter, which I believe is “Negative gravity on matter, normal on self” and I basically need to do that with forcefields. Anyone know how I might do this, or any addons effecting forcefields?

Way, hey, hold it. What are you looking trying to illustrate? Big bang? Galaxy formation? Interstellar clouds? Expanding Universe? No one really knows the precise mechanism of how those things are happening. They came up with this crazy idea of Dark matter / energy because universe is doing some strange things which mathematically cannot be explained. Man, they don’t even know how planet forms! According to the equations we have, matter simply will not collapse to make a planet. We don’t have the simulation to model any of those things. If you can come up with algorithm to simulate those things with computer you will be the next Nobel Price Winner!