Ker Than
for National Geographic News
December 18, 2009

Dark matter may have been "felt" for the first time deep in a Minnesota mine, physicists say.

Detectors in the mine, part of the Cryogenic Dark Matter Search experiment, were tripped recently by what might be weakly interacting massive particles, or WIMPs.
WIMPs are among the most popular candidates for dark matter, the invisible material that scientists think makes up more than 80 percent of the mass in the universe.

Recently detectors in the mine recorded two hits with "characteristics consistent with those expected from WIMPs," according to a statement posted on the Cryogenic Dark Matter Search Web site.

There is a one-in-four chance, however, that the particles detected are not dark matter but ordinary subatomic particles such as neutrons, the team cautions. (Related: "Dark Matter Proof Found Over Antarctica?")

Mike Shull, an astrophysicist at the University of Colorado at Boulder, also urged restraint in interpreting the results.

"I regard this as interesting but very much an interim 'progress report' on a promising technique," said Shull, who did not participate in the research.

"I hope they've detected [WIMPs]," he added, "It's exciting if it's true."