Dark-matter detector seeks deeper site

BBC : Eighty-three percent of the matter in the universe is dark matter, an unknown substance whose only detectable property so far is its gravitational mass. Identifying dark matter’s true nature will depend on finding another detectable property. The BBC’s Paul Rincon reports on a proposal to do just that in a deep underground mine in Canada. The proposal depends on moving an existing dark-matter detector from its current, shallower site in a mine in Minnesota.