The Universe is constantly expanding. It changes, creating new structures that merge. But how does our Universe evolve? Physicists at the University of Geneva (UNIGE), Switzerland, have developed a new code of numerical simulations that offers a glimpse of the complex process of the formation of structures in the Universe. Based on Einstein's equations, they were able to integrate the rotation of space-time into their calculations and calculate the amplitude of gravitational waves, whose existence was confirmed for the first time on February 12, 2016. The study is published in the journal Nature Physics.
Until now, scientists studied the formation of large-scale cosmological structures based numerical simulations of Newtonian gravitation. These codes postulate that space itself does not change, it is said to be static, while time goes on. The simulations that it allows are very precise if the matter in the Universe moves slowly (i.e., about 300 km per second). However, when the matter particles move at high speed, this code only allows approximate calculations. Furthermore, it does not describe the fluctuations of dark energy. Constituting 70% of the total energy of the Universe (the remaining 30% is made of dark matter and ordinary matter), it is responsible for the accelerated expansion of the Universe. Therefore, it was necessary to find a new way to simulate the formation of cosmological structures and allow the study of these two phenomena.
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