
Yesterday, the Dark Matter collaboration made an announcement in Venice, Italy that claimed dark matter, the elusive particle that theoretically accounts for 90% of the universe, had been detected on Earth.
The DAMA experiment has looked more directly for dark matter particles hitting the Earth. The experiment takes place in an underground laboratorythat lies beneath 1.4 kilometers of rock, inside the Gran Sasso mountain in Italy. The team looks for flashes of light in a sodium iodide detector.
The flashes mainly come from background “noise”, such as ordinary neutrons from radioactivity in the surrounding rock. But some might also come from dark matter particles, and, if so, the scientists expect to see seasonal variations in the signal because the Earth’s speed through our galaxy changes depending on its direction of motion.
All is not settled though, as the method used in Italy has not been successfully reproduced anywhere else.
But Halzen is wary. “The discussion about whether this is some unknown systematic effect remains,” he says.
Richard Gaitskell from Brown University at Providence, Rhode Island, US, and a member of two dark matter experiments – the Cyrogenic Dark Matter Search(CDMS) and the Xenon project – also remains skeptical, because no other experiment has seen signs of dark matter.
“Right now, it is very difficult to reconcile theoretically what they are seeing and what we are seeing,” says Gaitskell.
Fight! Fight!