http://www.smh.com.au/world/scientists-believe-they-may-have-detected-dark-matter-20091220-l7jn.html
Scientists believe they may have detected dark matter RICHARD ALLEYNE December 21, 2009 THE hunt for dark matter - the mysterious substance thought to account for a quarter of the mass of the universe - may be over. An international team of physicists believe they may have detected two particles of the elusive substance for the first time at the bottom of a US mine shaft. Scientists working on the Cryogenic Dark Matter Search, in a disused iron ore mine in Minnesota, say they have detected two weakly interacting massive particles (WIMPs), thought to make up dark matter, which was first hypothesised 80 years ago. If they are confirmed by observations next year, they would rank as one of the most important recent advances in physics and understanding of the cosmos. Dark matter, along with the equally elusive dark energy, is believed to make up about 90 per cent of the mass of the universe. We cannot see it but scientists think it is there due to the gravitational force it exerts. It could help account for the ''missing mass'' in the universe that would explain why galaxies stay together and rotate at their current speeds. The particles showed as two tiny pulses of heat deposited over the course of two years in chunks of germanium and silicon that had been cooled to a temperature near absolute zero (minus 273.15 degrees). The detectors are placed about a kilometre down to avoid them being affected by background radiation. But the scientists still said there was more than a 20 per cent chance that the pulses were caused by fluctuations in background radioactivity, so the results were tantalising, but not definitive. Craig Hogan, of the University of Chicago, said the finds were ''potentially very exciting''. He said three or four more WIMP-like interactions recorded over the next few years by the experiment would constitute proof of dark matter. ''That would be a huge transformation in how we do science,'' Dr Hogan said. ''We would have a new form of matter to study.'' Telegraph, London [Non-text portions of this message have been removed]
