Overview
A basic scientific tool to test theories in cosmology is to evaluate their consequences for the observable parts of the universe. One piece of observational evidence is the distribution of matter, including galaxies and intergalactic gas, which are observed today. Light emitted from more distant matter must travel longer in order to reach Earth, meaning looking at distant objects is like looking further back in time. This means the evolution in time of the matter distribution in the Universe can be observed.
The Millennium Simulation was run in 2005 by the Virgo Consortium, an international group of astrophysicists from Germany, the United Kingdom, Canada, Japan and the United States. It starts at the epoch when the cosmic background radiation was emitted, about 379,000 years after the universe began. The cosmic background radiation has been studied by satellite experiments, and the observed inhomogeneities in the cosmic background serve as the starting point for the corresponding matter distribution. Using the physical laws expected to hold in the currently known cosmologies, the initial distribution of matter is allowed to evolve, and the formation of galaxies and black holes in the simulation are recorded.
Read more about this topic: Millennium Run