A new computer simulation called Illustris takes into account everything from the large-scale filamentary structure of the universe all the way down to the level of star-forming gas clouds in individual galaxies.
Dark matter, dark energy and normal matter are all simulated in a cube 350 million light-years across, containing 41,416 realistic model galaxies.
To simulate the formation of galaxies, one must model the universe at three scales simultaneously: first, the large-scale structure of the universe; second, the galaxies themselves; and finally, the nebulas from which stars are born.
Galaxies are classified as elliptical, disk or irregular. Previous simulations of the universe had trouble producing disk galaxies like the Milky Way. Unlike previous attempts, the Illustris simulation naturally produces disk galaxies. One weakness of the simulation is that it still has trouble producing accurate low-mass galaxies.
The largest structures in the known universe are the galaxy filaments, or “great walls” of galaxy superclusters. The filaments form the boundaries between great voids in space. It is thought that the galaxy filaments form along a web-like distribution of dark matter, the dominant form of matter in the universe.