An Italian experiment is tantalizingly close to detecting dark matter

In the history of physics, there are occasional metaphorical shouts from the void that are observed once and never again. Now, an experiment underway in Italy to detect dark matter particles, the gravitationally attractive substance that makes up much of the universe, continues to produce tantalizing and positive results. The experiments to detect dark matter use different materials but similar principles: create a very still environment and then listen for the particle’s footsteps. 8,000 feet underground in an abandoned South Dakota mine, the LUX experiment also uses xenon to listen for dark matter’s faint beck. DAMA/LIBRA, beneath the Gran Sasso mountain in L’Aquila, uses crystals made of sodium iodide and thallium; the crystal lattice should, ideally, vibrate throughout if it is touched by a dark matter particle.