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The entire evolution of the cosmos, covering the 13.7 billion years since the Big Bang, has been accurately simulated by a supercomputer.
Describing this leviathan achievement in the Monthly Notices of the Royal Astronomical Society, researchers say that the model accurately positions the galaxies and other structures in our local universe, thereby indicating that our understanding of the forces that drive the evolution of the universe is correct.
According to the accepted model of cosmology, all astronomical events can be explained by the behavior of dark matter, which condenses into clumps known as haloes. Referred to as the Cold Dark Matter (CDM) model, this paradigm assumes that the accumulation of gases and other material around these haloes eventually leads to the formation of stars and galaxies, and has been used to explain several properties of the observable universe.
However, the study authors point out that most previous simulations using the CDM hypothesis have focused on random patches of sky rather than our own cosmic neighborhood – so they set out to determine whether or not the model could be used to accurately recreate the area of space surrounding the Milky Way galaxy.
They fed the complex physical equations that underpin the CDM model into a supercomputer called DiRAC COSmology MAchine (COSMA), located at Durham University. Based on these equations, the machine then proceeded to simulate the entire history of a patch of sky extending 600 million lightyears from our Solar System, represented by over 130 billion simulated particles.
Included in this region are the Virgo, Coma, and Perseus galaxy clusters, plus the Milky Way and Andromeda galaxies and other features such as the Local Void and the Great Wall. After meticulously checking the positioning of these simulated features against actual astronomical observations, the study authors determined the model to be accurate.
Commenting on this incredible feat, study author Matthieu Schaller explained in a statement that "these simulations demonstrate that the standard Cold Dark Matter Model can produce all the galaxies we see in our neighborhood. This is a very important test for the model to pass."
At the very center of the simulation (and our own Universe) is the Milky Way galaxy, and our nearest massive neighbor, the Andromeda galaxy (known as M31). Image Credit: Dr Stuart McAlpine
Co-author Carlos Frenk added that “the simulations simply reveal the consequences of the laws of physics acting on the dark matter and cosmic gas throughout the 13.7 billion years that our universe has been around.”
“The fact that we have been able to reproduce these familiar structures provides impressive support for the standard Cold Dark Matter model and tells us that we are on the right track to understand the evolution of the entire Universe."
Known as the SIBELIUS-DARK simulation, the model also revealed that our local patch of universe is somewhat anomalous, in that it contains an “underdensity” of dark matter in relation to the cosmic average. Despite this, the researchers say that their findings do not challenge or undermine the CDM model.
"This project provides an important bridge between decades of theory and astronomical observations," said study author Stuart McAlpine. “By simulating our Universe, as we see it, we are one step closer to understanding the nature of our cosmos.”
