Sudbury Neutrino Observatory
Quick Summary
The Sudbury Neutrino Observatory (SNO) was a research center located deep underground in a mine near Sudbury, Ontario, Canada. Its primary mission was to investigate the "solar neutrino problem," a long-standing puzzle in astrophysics.123
Scientists expected a certain number of neutrinos, subatomic particles produced by nuclear reactions in the Sun, to reach Earth. However, early experiments detected far fewer than predicted. The SNO, utilizing 1,000 tons of heavy water, was designed to detect all three types of neutrinos (electron, muon, and tau).243
In 2002, SNO announced groundbreaking results: the observed number of electron-neutrinos was indeed lower than expected, but the total number of all neutrino types matched solar models. This provided the first direct evidence that electron-neutrinos were changing into other types (oscillating) during their journey from the Sun to Earth. This discovery proved that neutrinos have mass, a finding that significantly advanced particle physics and earned Nobel Prizes for researchers involved.2435
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