One is for analyzing data. The data flow from our instrumentation is far, far greater than it was before. In his own work as a theoretical astrophysicist, however, the role of computers is to simulate the evolution of the universe using relatively well-defined models for the growth and structure of the universe, which come from fundamental physics, along with the suspected initial conditions. Ultimately we take the results and compare them against nature, Ostriker says. There exist a variety of different theories cold dark matter, hot dark matter, etc.
Computational methods allow the consequences to be developed in a fair amount of detail.
On the basis of observation, astrophysicists conclude that the development of large-scale structure in the universe involved the formation of deep gravitational potential wells. In these wells, matter collapses to 1,000 times the mean density of the universe, in regions several million light-years in size. The question that needs to be answered is whether researchers would have predicted the existence of such objects from each of the competing cosmological models, Ostriker says. You can use the computer to put in the initial conditions, and follow the equations of hydrodynamics, which is essentially all from standard physics, to see whether you get the same number of clusters, the same temperatures, the same separations, the same correlations, as you see in the real sky, he says. On the basis of this comparison to observations, you can eliminate some of the physical models.