Sudbury Neutrino Observatory

The Sudbury Neutrino Observatory (SNO) is a scientific facility in Canada designed to study neutrinos, tiny, nearly massless particles produced by the sun. Neutrinos are extremely difficult to detect because they rarely interact with matter. SNO uses a large tank of heavy water surrounded by sensitive detectors to observe neutrinos as they pass through. The observatory has provided important insights into the properties of neutrinos, including their ability to change types (or "flavors") as they travel, which has implications for our understanding of the sun and fundamental physics. It played a key role in solving the solar neutrino problem.