April 30, 2012
"The average human body gets hit by a particle of dark matter about once a minute, according to new calculations based on several dark matter detection efforts."
Excerpted from the article in the National Geographic Daily News by Jason Major:
Dark matter is an invisible form of material that's thought to exist because scientists have observed its apparent gravitational effects on galaxies and galaxy clusters. Scientists estimate that the mysterious substance makes up almost 80 percent of the matter in the universe.
So far no one's been able to pinpoint the particles that make up dark matter. But a leading candidate is a theoretical group known as Weakly Interacting Massive Particles, or WIMPs.
As the name implies, these hypothetical particles would have only a weak effect on regular, or baryonic, matter—they typically zip straight through most of the stuff in the universe, including people.
But WIMPs of certain masses can collide with atomic nuclei on occasion—and now it appears such collisions might happen more often than previously thought.
"Before we did this work, I thought a WIMP collided with one of your nuclei once in your lifetime," said Katherine Freese, a professor with the Michigan Center for Theoretical Physics at the University of Michigan.
"Turns out it's more likely to be one a minute."
» Return to the front page of The Hub