Supercomputers shed new light on dark matter
The simulation of an evolving galaxy by an international team of astrophysicists has provided new clues on where researchers should look to see dark matter. Dark matter is believed to make up 85 per cent of the Universe's mass. Its gravitational effects gave away its existence, but attempts to see dark matter with a telescope have so far failed. A new NASA apparatus - the Fermi Telescope - has been mapping the sky for several months. Its developers are hopeful that it will be able to detect dark matter, and this new simulation could increase its chances of doing so. The Virgo consortium - a team of scientists from Germany, the Netherlands, the UK and Canada - used some of Europe's largest supercomputers to create the simulation. It showed that the 'dark matter halo' surrounding our Milky Way expanded following a succession of violent collisions between smaller clumps of dark matter that were created by the Big Bang. The particles making up dark matter are an unknown substance. It is however believed that in the right conditions, they could produce gamma rays, and this is what could reveal them to the Fermi telescope. Gamma rays are produced when particles collide in areas where dark matter density is high. Scientists have previously argued that Fermi should search for gamma rays from the Milky Way's satellites, as the satellites' centres should be very dense. The Virgo team's findings contradict this line of thought, showing that it will be easiest to detect gamma rays away from the centre of the Milky Way. Focusing on the centre could lead to confusion as the gamma rays coming from other sources, such as the gas clouds where stars form, could be mistaken for the puffs of radiation emitted by dark matter. 'These calculations finally allow us to 'see' what the dark matter distribution should look like near the Sun, where we might stand a chance of detecting it,' said Professor Simon White, director of participating research centre the Max Planck Institute. The simulations were carried out at the Leibniz-Rechenzentrum in Munich, Germany, the University of Durham in the UK and the Netherlands' University of Groningen. 'Solving the dark matter riddle would be one of the greatest scientific achievements of our time. It is striking that even theoretical advances on such major scientific problems are now made by international collaborations such as ours,' said Professor Carlos Frenk, director of Durham University's Institute for Computational Cosmology. The findings have been published in the journal Nature.
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