Arthur B. McDonald 1943–

At a young age, I was curious about how the world and the Universe worked. This curiosity led me to a career in physics, and I began working as a researcher at the Chalk River Nuclear Laboratories. In 1982, I became a professor at Princeton University, returning to Queen’s University in Kingston, Ontario in 1989 to lead the Sudbury Neutrino Observatory (SNO).

SNO is a giant neutrino detector built two kilometres beneath Earth’s surface in a mine in Sudbury, Ontario. My team and I captured and studied neutrinos: tiny particles emitted by the Sun. Although minute, these neutrinos were the key to understanding something as large as the Sun. All of our hard work paid off, and our research was very successful.

We showed that neutrinos have mass: something which was previously assumed impossible. Furthermore, our studies demonstrated that neutrinos change from one type to another on their way from the Sun to Earth. This discovery proved to astrophysicists that their model of the Sun was accurate.

I am proud to have led one of the most important physics experiments of the twentieth century. Our findings changed the laws of physics, and allowed us to look into the structure of the Universe.