BIG DATA
Computer simulations unlock the mysteries of the Universe
As part of the "Horizon Project", a team of French scientists, led by Romain Teyssier, Astrophysicist at CEA, has completed the largest simulation ever carried out of structure formation in the Universe. This simulation, which used the new Bull supercomputer at the Research and Technology Computing Center (CCRT), will enable astrophysicists to compare their models with astronomical observations with unprecedented realism. 
The great advances achieved recently in computer science imply ever-greater leaps in scientific progress. In Astrophysics, solving the equations of fluid mechanics using more effective algorithms and increasingly more powerful supercomputers helps us to understand how structures form in the universe. "Starting from the initial conditions of our universe, that can be observed directly on the Cosmic Microwave Background, it is possible to compute individual trajectories of a large numbers of particles in order to describe the cosmological fluid," explained Romain Teyssier. With nearly 70 billion particles and over 140 billion meshes, the computation performed at the CCRT is an absolute record for a simulated N-body system. For the first time in the history of high performance computing, it is possible to simulate half the observable universe, while being able to resolve a galaxy like the Milky Way with more than hundred particles! To simulate such volumes in such detail, the Horizon team ran the "RAMSES" code on the 6144 Intel Itanium2 processors of the Bull NovaScale 3045 supercomputer recently installed at CCRT. This code, developed at CEA in conjunction with astrophysicists of the Horizon Project, makes use of an adaptive gridV that provides unprecedented spatial resolution (equivalent to a cubic grid with side length of 262,144 grid points!). Thanks to experts of Bull and CCRT, the program took full advantage of the computer resources for nearly two months, using over 18 Terabytes of RAM and generating approximately 50 Terabytes of data to disk. The same project, performed on a personal computer, would have required more than thousand years to complete! "With this new simulation, we will be able to predict how matter is distributed in the Universe with great precision and realism," continued Romain Teyssier. "We will soon be in a position to compare our model with full-sky observations, such as the one that will be shortly available thanks to the Planck space mission that will be launched by the European Space Agency in 2008. We will also be able to prepare future experiments on gravitational lensingVI, such as the "Dark UNiverse Explorer", a new project for determining the nature of dark energy."
The great advances achieved recently in computer science imply ever-greater leaps in scientific progress. In Astrophysics, solving the equations of fluid mechanics using more effective algorithms and increasingly more powerful supercomputers helps us to understand how structures form in the universe. "Starting from the initial conditions of our universe, that can be observed directly on the Cosmic Microwave Background, it is possible to compute individual trajectories of a large numbers of particles in order to describe the cosmological fluid," explained Romain Teyssier. With nearly 70 billion particles and over 140 billion meshes, the computation performed at the CCRT is an absolute record for a simulated N-body system. For the first time in the history of high performance computing, it is possible to simulate half the observable universe, while being able to resolve a galaxy like the Milky Way with more than hundred particles! To simulate such volumes in such detail, the Horizon team ran the "RAMSES" code on the 6144 Intel Itanium2 processors of the Bull NovaScale 3045 supercomputer recently installed at CCRT. This code, developed at CEA in conjunction with astrophysicists of the Horizon Project, makes use of an adaptive gridV that provides unprecedented spatial resolution (equivalent to a cubic grid with side length of 262,144 grid points!). Thanks to experts of Bull and CCRT, the program took full advantage of the computer resources for nearly two months, using over 18 Terabytes of RAM and generating approximately 50 Terabytes of data to disk. The same project, performed on a personal computer, would have required more than thousand years to complete! "With this new simulation, we will be able to predict how matter is distributed in the Universe with great precision and realism," continued Romain Teyssier. "We will soon be in a position to compare our model with full-sky observations, such as the one that will be shortly available thanks to the Planck space mission that will be launched by the European Space Agency in 2008. We will also be able to prepare future experiments on gravitational lensingVI, such as the "Dark UNiverse Explorer", a new project for determining the nature of dark energy."