James Peebles, Canadian-born American physicist who was awarded the 2019 Nobel Prize for Physics for his work on physical cosmology. He received one half of the prize; the other half was awarded to Swiss astronomers Michel Mayor and Didier Queloz.

Peebles received a bachelor’s degree in 1958 from the University of Manitoba and a doctorate in 1962 from Princeton University. He remained at Princeton for the remainder of his career, becoming an assistant professor in 1965 and a full professor in 1972. He became the Albert Einstein Professor of Science in 1984 and a professor emeritus in 2000.

His book Physical Cosmology (1971) established the framework for a series of challenging new theoretical proposals that helped shape the field of cosmological studies.

Peebles has written many influential and provocative articles in addition to his important books. His contributions have been recognized with honorary degrees from the University of Toronto, University of Chicago, McMaster University, University of Manitoba, University of Newcastle-upon-Tyne, and the Université Catholique de Louvain. He has also received important awards, including the Eddington Medal of the Royal Astronomical Society (1981) and the Gold Medal of the Royal Astronomical Society (1998).