Researchers find elusive dark matter
Scientists working in a 2,000-mile deep copper mine in Minnesota think they have identified the never-before-seen substance.
Wed, Feb 17, 2010 at 08:05 PM
Closeup of a CDMS detector, made of crystal germanium. (Credit: DOE/Fermi National Accelerator Laboratory)
Dark matter is one of the most mysterious substances in the universe. It neither reflects nor absorbs light but yet makes up as much as 23 percent of the universe. It is believed to be the extremely powerful force that makes galaxies spin more rapidly, a phenomenon that cannot be explained by gravity. Despite plentiful evidence of its influence, no one has ever found physical evidence of dark matter — until now.
ScienceDaily.com reports that physicists working 2,000 miles underground in a former Minnesota mine believe they have witnessed dark matter. Working under the shield of the Earth’s crust, scientists don’t have to screen out all the cosmic rays that bounce around the Earth’s surface. The findings are part of a nine-year search. The experiment, called the Cryogenic Dark Matter Search II, has yielded two possible detections of dark matter.
The research has zeroed in on weakly interacting massive particles, or WIMPs. WIMPs are what scientists consider comparable to the masses of standard atomic nuclei. They are thought to have little or no effect on ordinary matter. However, when they bounce off standard atomic nuclei, they apparently leave behind a small amount of energy that should be possible to detect. The scientists used 30 hockey-puck-sized germanium and silicon detectors cryogenically frozen to negative 459.58 Fahrenheit. They were arranged to "kick" or "bounce" away dark-matter particles.
Researchers are quick to point out that nothing is confirmed at this point. Durdana Balakishiyeva is a postdoctoral associate in physics at University of Florida who has participated in dark matter studies. As the physicist told Science Daily, "Up until now, not only us, but everybody was operating without statistics: we were blind in that sense. But now we can speak of statistics in some way."
This possible discovery has energized scientists across the globe to search for dark matter confirmation. Tarek Saab is another University of Florida researcher on the task. As Saab proposes, "It is expected or certainly hoped that in the next five years or so, someone will see a clear signal."
For further reading: