Getting to grips with dark matter: simulating the entire universe!
French researchers have performed the first-ever computer model simulation of the structuring of the entire observable universe, starting at the Big Bang and continuing right up to the present day. These simulation efforts make it possible to see how 550 billion particles have evolved. The researchers involved in the simulation are based at the Observatoire de Paris, the National Centre for Scientific Research (CNRS) and the Université Paris Diderot. This first simulation of the standard model of the universe with a cosmological constant is the first part of a three-part project titled DEUS ('Dark Energy Universe Simulation'), which is being carried out using the Grand Equipement National de Calcul Intensif's (GENCI) new supercomputer called CURIE, housed at the CEA's (Commissariat à L'énergie Atomique et aux Energies Alternatives) 'Très Grand Centre de Calcul' (TGCC). The supercomputer CURIE can perform 2 million billion operations per second. The aim of the project is to shed light on the nature of dark energy and its effects on cosmic structure formation, and hence on the distribution of dark matter and galaxies in the universe. The next two stages of the simulation will focus on cosmological evolution of models with dark energy, the mysterious component introduced to account for the accelerated expansion of the universe. The aim is to go some way to finding out what imprint dark energy leaves on cosmic structure, and how the nature of dark energy can be inferred from observing the distribution of matter in the universe. Their work so far on the simulation of the standard cosmological model has already shed light on a number of important properties concerning the distribution of matter in the universe. The team has successfully estimated the total number of galaxy clusters with a mass larger than a hundred thousand billion solar masses. These clusters currently amount to 144 million. The researchers have also found that the first galaxy cluster of this type formed when the universe was only 2 billion years old and the most massive cluster in the observable universe today weighs 15 quadrillion (or 15 thousand trillion) solar masses. The data generated by the run has also allowed the scientists to evaluate spatial distribution of dark matter density fluctuations in the universe. These fluctuations have the same origin as those found in the Cosmic Microwave Background radiation, resulting from the Big Bang and observed by the WMAP and Planck satellites. These measurements were obtained in a simulation covering the entire evolutionary history of the universe with previously unattained precision and on a much wider range of scales, from a few millionths to the size of the entire observable universe. The entire DEUS project will use more than 30 million hours (about 3,500 years) of computing time on nearly all the central processing units (CPUs) of CURIE. More than 150 PBytes of data (the equivalent of 30 million DVDs) are generated throughout the computing runs. Thanks to an advanced and innovative data reduction process developed by the researchers, the amount of useful stored data can now be reduced to 1 PByte. The final results from the DEUS researchers' voyages across the full observable universe are expected at the end of May.For more information, please visit:National Centre for Scientific Research (CNRS), Délégation Paris Michel-Ange:http://www.cnrs.fr/paris-michel-ange/
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