Deep in an Australian Gold Mine, Dark Matter's Last Stand

What’s the Latest?

About 80 percent of all the mass in the universe is missing, or least we can’t detect it with our scientific instruments. Strange, but true, at least according to our current conception of certain physical laws. Among other functions, this missing mass, which scientists have dubbed dark matter, is what keeps galaxies spiraling instead of being flung apart. So where is the missing stuff? Scientists are looking for it everywhere, including at the bottom of an Australian gold mine. At the bottom of a mine, they figure, all the cosmic rays shooting through the Earth will have been diffused, allowing their new class of instruments to pick up traces of the elusive dark matter.

What’s the Big Idea?

The going theory is that dark matter is composed of “weakly interacting massive particles, or WIMPs, which should occasionally collide with ordinary atoms and create a telltale signal.” That signal is what physicists hope to find in Australia. To date, only two instruments (of the many scientists have placed around the globe) have measured WIMPs directly. If the current experiment doesn’t yield positive results, scientists say they will be forced to go back to the drawing board. Project leader Elisabetta Barberio of the University of Melbourne said: “If we don’t see anything, those experiments [which failed to detect WIMPs] will be right.”