OUR COSMOS

Earth on the 'Wimp highway'

Earth would be sitting in this stream of Wimps (Image by David Low)
Mysterious sub-atomic particles from another galaxy could be raining down on planet Earth, according to a collaboration of astronomers. If so, it could explain controversial results from a particle-detection experiment deep inside mountains to the east of Rome.
The story concerns Wimps - weakly interacting massive particles - which astronomers think may make up the bulk of the Universe. For every kg of material made up from atoms like the ones we have in our bodies, or which make up the stars, there are up to 20kg of something completely different, whose principal quality is that it has never been actually observed directly by scientists.
Which is why they call it dark matter. But they know it is there because its effect on the movements of galaxies can be weighed.
If Wimps exist, they would fill the spaces between the stars, and would interact with normal matter so weakly that they would pass right the way through the Earth.