To reproduce this process on a computer, they changed Newton's laws of gravity. The galaxies that were created in computer computing are similar to those in existence today. According to scientists, their assumptions could solve many of the mysteries of modern cosmology.
Cosmologists suggest that after the Big Bang, matter was not evenly distributed. Denser places attracted more material from the environment due to stronger gravitational forces. Over several billion years, these gas clusters eventually formed the galaxies we see today.
An important component of this theory is dark matter. On the one hand, it is believed to be responsible for the initial uneven distribution that led to the accumulation of gas clouds. This also explains some of the surprising observations. For example, stars in rotating galaxies often move so fast that they have to fly out of them. It appears that galaxies have an additional source of gravity that prevents this from happening that cannot be seen with telescopes: dark matter. But there is still no direct evidence of its existence.
“Perhaps the gravitational forces themselves do not behave as previously thought,” explains Professor Pavel Krupa. This theory is called Modified Newtonian Dynamics (MOND). It was discovered by the Israeli physicist Mordechai Milgrom. According to the theory, the attraction between two masses obeys Newton's laws only up to a certain point. At very low accelerations, as in the case of galaxies, it becomes much stronger. This is why galaxies do not disintegrate due to the speed of rotation.
In the simulation, the scientists used a computer program for complex gravity calculations developed by Krupa's group. In MOND, the attraction of a body depends not only on its own mass, but also on whether other objects are in its vicinity.
The scientists then used the software to simulate the formation of stars and galaxies, starting with a gas cloud several hundred thousand years after the Big Bang. “In many ways, our results are surprisingly close to what we actually observe with telescopes,” explains Krupa. For example, the distribution and speed of stars in computer-generated galaxies follow the same pattern as seen in the night sky. “In addition, our simulations have led mainly to the formation of rotating disk galaxies, such as the Milky Way, and almost all other large galaxies that we know,” says the scientist. "Dark matter simulations, on the other hand, basically create galaxies without separate material disks - a discrepancy with observations that are difficult to explain."
Calculations based on the existence of dark matter are also very sensitive to changes in parameters such as the frequency of supernovae and their effect on the distribution of matter in galaxies. However, in the modeling of MOND, these factors hardly played a role.
However, the recently published results from Bonn, Prague and Strasbourg are untrue in every way. “Our modeling is only the first step,” emphasizes Krupa. For example, scientists have so far made very simple assumptions about the original distribution of matter and conditions in the young universe. “Now we have to repeat the calculations and include more complex influencing factors. Then we'll see if the MOND theory really explains reality."
The results are published in the Astrophysical Journal.