Millennium Run

The Millennium Simulation is a project of the Virgo Consortium, a group of cosmologists from Germany, Great Britain, Canada, Japan and the United States under the leadership of the Max Planck Institute for Astrophysics in Garching near Munich. The aim is to produce a computer simulation to clarify the cosmological highly interesting question of how could form the present-day galaxies and stars from the structureless directly after the Big Bang universe. In summer 2005 results to be presented, which show the emergence of large-scale irregularities of small incorporated manipulations.

The simulation

Basis of the simulation is not ordinary matter, but dark matter, which accounts for about 80 percent of the mass of the universe according to the common opinion of experts. This kind of matter could not be driven by the strong electromagnetic radiation from the hot early universe apart and clumped so earlier than the "normal " matter obviously. Therefore, dark matter for the structure formation of the universe probably played the most important role.

Even with today's best supercomputers, it is not possible to model the processes in the entire known universe. Therefore, this was limited to a cube- shaped cutout 500 MPC / h edge length, z = 0 corresponds to the period length of 685 million parsecs or 2.2 billion light years. In this section dark matter of 10 trillion solar masses to 10 billion virtual particles was introduced evenly distributed. To start the simulation of the distribution of the dark matter density fluctuations were tiny impressed. Also, in reality such irregularities must have been present, as is known from the observation of the cosmic background radiation. The strength of the irregularities of the simulation corresponds approximately to the real universe in 10 million years after the Big Bang. The program now calculated the motion of each particle due to gravity with a stride length of about one million years. As the real universe was laid an expanding space also based on the simulation. The simulation ended after about 11,000 time steps, which corresponds to a period of 14 billion years ago, which is the age of the universe today. The simulation took 28 days for 512 processors were needed.

In a second simulation step into normal matter was modeled in the simulation according to the distribution of dark matter, which illuminated stars and galaxies forms could be visualized.

The result

The simulation shows how the introduced density fluctuations gradually increase so that eventually creates a lumpy structure as that of the present-day universe, because clumped areas exert a greater attraction to other particles. At the end of the simulation, mass gatherings had formed in the size of galaxies and clusters of galaxies. It was overall a net-like structure with fractal properties emerged.

The simulation results agree very well with the observations of reality, thereby providing a model of the whole universe has been created for the first time. The Millennium Simulation was also confirmed that the first quasars have already formed shortly after the Big Bang, which until then was a contentious issue among scientists, and that these objects are found in galaxy centers.

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