Takaaki Kajita of the University of Tokyo and Arthur B. McDonald of Queen’s University in Canada were awarded the Nobel Prize in Physics on Tuesday for their discovery of neutrino oscillations, which show that neutrinos — a kind of subatomic particle — have mass.
Neutrinos are the second most abundant subatomic particles in the universe. Their existence was predicted in 1930, but for decades, they remained some of the most enigmatic elements of astrophysics.
Dr. Kajita was part of a team of researchers who in 1998 announced that they had found the existence of mass in the notoriously elusive particles. In 1999, Dr. McDonald, the director of the Sudbury Neutrino Observatory, showed that neutrinos, which can be found in three “flavors,” could oscillate from one flavor to another, demonstrating that they do not lack mass.
The universe is swamped in neutrinos that are left over from the Big Bang, and many more are created in nuclear reactions on earth and in the thermonuclear reactions that power the sun.
Once thought to be massless and to travel at the speed of light, they drift through the earth and our own bodies like moonlight through a window. Knowing that they can change identities means that they have mass, and that has helped cosmologists understand how the universe has evolved and how the sun works and perhaps will help them improve their attempts to create fusion reactors on earth.
Dr. Kajita and Dr. McDonald will share 8 million Swedish kronor, or about $960,000. They joined 199 laureates, including Albert Einstein, Niels Bohr and Marie Curie, who have been honored with the prize since 1901.
The announcement of the prize was made in Stockholm by Goran K. Hansson, permanent secretary of the Royal Swedish Academy of Sciences, which appoints the prize committee.
(via New York Times)
