What is simulated universe theory

Mystery of "cold dark matter catastrophe" solved

Zurich - According to its own statements, an international research group has managed to resolve a contradiction in the model of cold dark matter (the so-called "cold dark matter catastrophe") when simulating the formation of disk-shaped dwarf galaxies. This model explains the distribution of galaxies and standard matter in the universe. When used in very large dimensions - on the order of billions of light years - model predictions and astronomical observations are in harmony, the University of Zurich announced in a broadcast.

mystery

In the order of magnitude of individual galaxies - that is, in dimensions of a hundred to a thousand light years - the model fails and leads to a contradiction with the measured reality. According to the model forecast, the center of a galaxy would have to rotate faster than the astronomical measurements actually indicate. In addition, there would have to be a much higher density of cold dark matter in the center of a galaxy than can be the case.

For almost two decades, researchers have been trying to find an explanatory model for the different behavior of dark matter in different orders of magnitude. Now an international research group, including Lucio Mayer from the University of Zurich as one of the three scientific directors, describes the solution to the riddle in the science journal "Nature".

Solution thanks to simulation

The researchers simulated the formation of disk-shaped dwarf galaxies and for the first time modeled not the behavior of the cold dark matter, which is controlled solely by gravity, but also took into account the complex influence of normal, visible matter (baryonic matter). Dark matter makes up the lion's share of 83 percent in a galaxy, but, as the scientists were able to show in their publication, it is also influenced by baryonic matter.

With the help of various supercomputers, it was demonstrated in the model that not only gases but also cold dark matter are flung out of the center of the galaxy in a supernova explosion. Supernova explosions remove large amounts of normal, visible matter from the center of the galaxy in one fell swoop. This leads to the fact that the dark matter expands more, its density decreases and consequently the rotation speed of the dwarf galaxy decreases. This resolved the apparent contradiction to the model and made the "cold dark matter catastrophe" explainable, according to the researchers. (red)