Dark Matter Under A Rock

The quest for dark matter has been long and arduous, trying to find a shred of its faint traces anywhere they think it could have been which led scientists to look for the elusive evidence under the earth's crust.

For many decades, the favored candidates for dark matter particles have been hypothetical shy things called weakly interacting massive particles, or WIMPs. Many experiments search for them by looking for evidence that a WIMP has come by and knocked regular matter around. In this scenario, a WIMP would tap an atomic nucleus via the weak force.

After searching for these faint pings for decades, scientists have little hard evidence to show for it. Now a team of physicists in Poland, Sweden and the U.S. has another idea.

Look not to the germanium and the xenon and the scintillators in detectors buried beneath the earth’s crust, they argue: Look to the planet’s crust itself. In the rock record, where stories of our solar system’s past lay buried, we might find the fossilized recoil of startled atomic nuclei, the frozen footprints of a WIMP.

(Image credit: Shmahalo/Quanta Magazine)