Congratulations Arthur McDonald, amazing stuff:

http://www.ctvnews.ca/sci-tech/eurek...very-1.2597096

McDonald led the research group in Canada, where he is the director of the Sudbury Neutrino Observatory, located in a northern Ontario nickel mine two kilometres underground.

McDonald said working 2,100 metres underground allowed scientists to avoid radiation.

"It's the same radioactivity that makes the northern lights glow. We didn’t want our detectors to glow," he said.

McDonald said, in that environment, scientists were able to observe neutrinos that are produced by same kind of nuclear reactions that power the sun. The scientists were able show that neutrinos change their type as they travel from the core of the sun to a detector in the mine, "which means they have mass – something that is beyond the standard model of elementary physics and a real contribution to science in that way."

Realizing neutrinos had mass was "a real eureka moment," McDonald said.
http://www.ctvnews.ca/sci-tech/eurek...very-1.2597096