Peebles was awarded half of theNobel Prize in Physics in 2019 for his theoretical discoveries inphysical cosmology.[3] He shared the prize withMichel Mayor andDidier Queloz for their discovery of an exoplanet orbiting a sun-like star.[4][5][6] 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."[7]
Peebles has described himself as a convincedagnostic.[8]
Peebles was born on April 25, 1935, in St. Vital in present-dayWinnipeg,Manitoba, Canada, the son of Ada Marion (Green), a homemaker, and Andrew Charles Peebles, who worked for theWinnipeg Grain Exchange.[9] He completed hisBachelor of Science at theUniversity of Manitoba. He then went on to pursue graduate studies atPrinceton University, where he received hisDoctor of Philosophy degree 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 ofRobert Dicke.[10] He remained at Princeton for his whole career. Peebles was a Member in the School of Natural Sciences at theInstitute for Advanced Study during the academic year 1977–78; he made subsequent visits during 1990–91 and 1998–99.[11]
Most of Peebles's work since 1964 has been in the field ofphysical 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.[12] Peebles has made many important contributions to theBig Bang model. In 1965, Peebles, with Dicke and two other Princeton physicists, connected thecosmic microwave background radiation discovered byArno Allan Penzias andRobert Woodrow Wilson to a plasma cooling event in the early universe. This connection created a sensation leading to wide acceptance of the Big Bang model among astronomers and physicists.[13]: 202 Peebles then used the temperature of that radiation, 3K, to compute the compute the first accurate estimate of primordial elemental abundance based on nuclear physics and cosmic expansion, a model calledBig Bang nucleosynthesis.[13]: 204
Along with making major contributions todark matter, anddark energy, he was the leading pioneer in the theory of cosmicstructure 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.[14] 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 (CMB) radiation that immediately attracted attention [...] both experimentalists interested in measuring the properties of this radiation and theorists, who joined in analyzing the implications".[15] 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."[16]
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 theprimordial isocurvature baryon model for the development of the early universe.[17] Similarly, Peebles contributed to establishing the dark matter problem in the early 1970s.[18][19][20] Peebles is also known for theOstriker–Peebles criterion, relating to the stability ofgalactic formation.[21]
Peebles's 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 withMichel Mayor andDidier Queloz who had been the first to discover anexoplanet around amain sequence star.[22]
^abKragh, Helge (2007).Conceptions of cosmos: from myths to the accelerating universe: a history of cosmology. Oxford ; New York: Oxford University Press.ISBN978-0-19-920916-3.
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