Neutrinos and the Sun: How the Sudbury Neutrino Observatory Solved the Solar Neutrino Problem.

The idea of using Canada'sunique stockpile of heavy water in an excellent site, deep underground at INCO's Creighton Mine near Sudbury, to look at neutrinos from the Sun, was developed into a Canada- United States-Great Britain proposal to build the Sudbury Neutrino Observatory in the late 1980's. The laboratory was funded by the three countries in 1990 and constructed over the next 8 years. In April 2002, SNO scientists provided proof positive form the analysis of more than two years of neutrino data, that neutrinos change from one species to another as they travel from the Sun, thus solving a 30 year puzzle of missing solar neutrinos. In the presentation, the construction and operation of SNO will be reviewed, and the SNO results and their astrophysical and particle physics implications will be described. An expansion of the underground facilities, to accommodate new neutrino and Dark Matter experiments has just been funded, and some plans for the new SNOLAB facility will also be outlined.