Sudbury Neutrino Observatory (SNO)

The Sudbury Neutrino Observatory (SNO) was a scientific facility in Canada designed to study neutrinos—tiny, nearly massless particles produced by the Sun’s nuclear reactions. Using a large tank filled with heavy water (deuterium oxide), SNO could detect different types of neutrinos and determine their origins. Its key achievement was confirming that neutrinos change "flavor" (type) during their journey from the Sun to Earth, solving a long-standing puzzle about neutrino behavior. This discovery advanced our understanding of particle physics and solar processes, proving that neutrinos have mass and helping refine models of how the Sun produces energy.