Phillip James Edwin Peebles is a Canadian-American astrophysicist, astronomer, and theoretical cosmologist who is currently the Albert Einstein Professor of Science, Emeritus, at Princeton University. He is widely regarded as one of the world's leading theoretical cosmologists in the period since 1970, with major theoretical contributions to primordial nucleosynthesis, dark matter, the cosmic microwave background, and structure formation. Peebles was awarded half of the Nobel Prize in Physics in 2019 for his theoretical discoveries in physical cosmology. He shared the prize with Michel Mayor and Didier Queloz for their discovery of an exoplanet orbiting a sun-like star. In his award presentation, Peebles noted that he does not prefer the term "Big Bang Theory", since "it connotes the notion of an event and a position, both of which are quite wrong." While much of his work relates to the development of the universe from its first few seconds, he is more skeptical about what we can know about the very beginning, and stated, "It's very unfortunate that one thinks of the beginning whereas in fact, we have no good theory of such a thing as the beginning." Peebles has described himself as a convinced agnostic.
Early life
Peebles was born on April 25, 1935 in St. Boniface, in present-day Winnipeg, Manitoba, Canada, the son of Ada Marion, a homemaker, and Andrew Charles Peebles, who worked for the Winnipeg Grain Exchange. He completed his bachelor of science at the University of Manitoba. He then went on to pursue graduate studies at Princeton University, where he received his Ph.D. in physics in 1962, completing a doctoral dissertation titled "Observational Tests and Theoretical Problems Relating to the Conjecture That the Strength of the Electromagnetic Interaction May Be Variable" under the supervision of Robert Dicke. He remained at Princeton for his whole career. Peebles was a Member in the School of Natural Sciences at the Institute for Advanced Study during the academic year 1977–78; he made subsequent visits during 1990–91 and 1998–99.
Academic career
Most of Peebles' work since 1964 has been in the field of physical cosmology to determine the origins of the universe. In 1964, there was very little interest in this field and it was considered a "dead end" but Peebles remained committed to studying it. Peebles has made many important contributions to the Big Bang model. With Dicke and others, Peebles predicted the cosmic microwave background radiation. Along with making major contributions to Big Bang nucleosynthesis, dark matter, and dark energy, he was the leading pioneer in the theory of cosmic structure formation in the 1970s. Long before it was considered a serious, quantitative branch of physics, Peebles was studying physical cosmology and has done much to establish its respectability. Peebles said, "It was not a single step, some critical discovery that suddenly made cosmology relevant but the field gradually emerged through a number of experimental observations. Clearly one of the most important during my career was the detection of the cosmic microwave background radiation that immediately attracted attention both experimentalists interested in measuring the properties of this radiation and theorists, who joined in analyzing the implications". His Shaw Prize citation states "He laid the foundations for almost all modern investigations in cosmology, both theoretical and observational, transforming a highly speculative field into a precision science." Peebles has a long record of innovating the basic ideas, which would be extensively studied later by other scientists. For instance, in 1987, he proposed the primordial isocurvature baryon model for the development of the early universe. Similarly, Peebles contributed to establishing the dark matter problem in the early 1970s. Peebles is also known for the Ostriker–Peebles criterion, relating to the stability of galactic formation. Peebles' body of work was recognized with him being named a 2019 Nobel Laureate in Physics, "for theoretical discoveries in physical cosmology"; Peebles shared half the prize with Michel Mayor and Didier Queloz who had been the first to discover an exoplanet around a main sequence star. Peebles was elected as a member of the American Academy of Arts and Sciences in 1977 and a member of the National Academy of Sciences in 1988.
