spacetoday.net: Astronomers take temperature of dark matter

Posted: Tue, Feb 7, 2006, 7:56 PM ET (0056 GMT)
Astronomers have measured the temperature of dark matter that predominates galaxies like the Milky Way, and found it to be much warmer than expected. Astronomers used the Very Large Telescope in Chile to observe 12 dwarf galaxies that orbit the Milky Way, studying their movements. Based on those observations, researchers concluded that the dark matter that surrounds the Milky Way consists of blocks at least 1,000 light-years across, and thus have a temperature of about 10,000 degrees C, nearly twice as warm as the surface of the Sun. That temperature was warmer than expected, since previous work suggested that dark matter was much colder. The nature of dark matter remains a mystery, although these observations suggest that dark matter may be made of weakly-interacting massive particles, or WIMPs.