TECHNOLOGY FOR CHANGE

WIMPs in Mines: A Glimpse into the Dark?

Dave Greenfield | Date: 01-13-10 | Comments

Researchers are hopeful that weakly interacting massive particles, or WIMPs, may have tripped detectors deep inside a Minnesota mine. If so, it may be the first actual observation of dark matter.

The stuff that makes up galaxies thousands of light-years away may have finally been discovered here at home.

In December, researchers think that half a mile below ground, in a Minnesota mine, weakly interacting massive particles, or WIMPs, may have tripped detectors placed by the Cryogenic Dark Matter Search Experiment. WIMPs are thought to be dark matter particles that can interact with normal atoms.

The mystery of dark matter has captivated the interest and imagination of everyone from physicists and astronomists to writers and philosophers. Far from being a void, researchers are finding that dark matter is actually quite structurally complex�and we may be one step closer to understanding it. Researchers at UC Berkeley constructed a computational model of the universe in 2003 that extended any work previously done.

�The currently favored cosmological model tells us that the universe is made of mainly two dark components�dark matter and dark energy,� says Berkeley astronomy professor Chung-Pei Ma. In fact, according to researchers, the dark forces, as it were, account for almost 99 percent of the universe�s mass. The stars, planets, moons and other visible objects make up only 1 percent. There is a lot more to the universe, and to dark matter, than we can see.

Yet until last December, dark matter largely remained theory with little actual observation. Hence the excitement over the WIMP incident. But even then, the

discovery has been shrouded in �may haves,� and �might bes.� Scientists simply cannot be sure what they detected was actually dark matter.

Dark matter cannot be measured per se, but its effect on the atoms around it can be. Scientists use a billiard analogy to explain: A WIMP particle is like a billiard ball. It hits another ball, an atom. Even if you can�t track the WIMP ball, the collision leaves evidence of the collision in the form of heat.

The Cryogenic Dark Matter Search Experiment declined to comment on the potential discovery, but it did announce it found �characteristics consistent with those expected from WIMPs.� It also said, however, that there is a 25 percent chance that what it detected wasn�t dark matter at all. They could be ordinary neurons or other subatomic particles.

The potential of the find is enormous: If confirmed, scientists could work on better techniques for detecting dark matter. They could begin working on determining the origin of the matter and understanding the cosmos in a way that has never been dreamed of.

�I regard this as interesting but very much an interim �progress report� on a promising technique. I hope they�ve detected [WIMPs]. It�s exciting if it�s true,� says University of Colorado at Boulder astrophysicist Mike Shull (who was not involved with the project).