A persistent claim to have detected dark matter looks wrong

NEGATIVE RESULTS are rarely reported widely. But they can be important. And this week sees one such--the possible demolition of what had been thought to be a sign of dark matter. Twenty years ago results from DAMA, a particle detector housed under a central-Italian mountain, suggested that this mysterious stuff, thought to make up 85% of all matter in the universe, had been detected. DAMA's operators saw an oscillating signal, peaking in June and at its lowest ebb in December, which was consiste...