Edwin Ernest Salpeter Kurt Gottfried, Saul Teukolsky, and Ira Wasserman

Citation: Physics Today 62, 3, 65 (2009); doi: 10.1063/1.3099585 View online: https://doi.org/10.1063/1.3099585 View Table of Contents: http://physicstoday.scitation.org/toc/pto/62/3 Published by the American Institute of Physics

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Testing relativity from the 1919 eclipse—a question of bias Physics Today 62, 37 (2009); 10.1063/1.3099578 Ed paid close attention to phenome- nology and often predicted new phe- obituaries nomena. The most famous such predic- tion, also made independently by To notify the community about a colleague’s death, subscribers can visit Yakov Zel’dovich, was that black holes http://www.physicstoday.org/obits, where they can submit obituaries (up to 750 could be revealed by the radiation emit- words), comments, and reminiscences. Each month recently posted material will be ted by accreting gas; that knowledge summarized here, in print. Select online obituaries will later appear in print. has become a standard way of identify- ing black holes. The range of Ed’s contributions to as- Edwin Ernest trophysics was due to his mastery of a broad array of physics concepts and to Salpeter his intuitive ability to identify the critical variables in any problem and to see Edwin Ernest Salpeter, among the most scaling relations among them. Once he influential, prescient, and innovative had that arsenal in hand, the rest was, astrophysicists of the past half century, to him, just details. died of leukemia at his home in Ithaca, Ed’s influence on astrophysics went New York, on 26 November 2008. well beyond his discoveries and publica- Ed was born in Vienna on 3 Decem- tions. He trained many gifted graduate ber 1924. He and his family emigrated students and postdocs who hold posi- to Australia in 1938 following the Nazi tions in leading institutions across the takeover of Austria. After he earned a globe. BSc in 1944 and an MSc in 1945, both Ed’s reach extended beyond the from the University of Sydney, a presti- physical sciences. His wife Miriam was gious scholarship allowed him to be- a professor of neurobiology at Cornell come a doctoral student of Rudolf University, and in his later years Ed Peierls at the University of Birmingham contributed mathematical models to in the UK; he received his PhD in quan- her research on the interaction of nerves tum electrodynamics in 1948. Peierls and muscle fibers. After she died in and his old friend Hans Bethe often sent Edwin Ernest Salpeter 2000, he ran her laboratory for a time, outstanding students to each other to then became a partner with his daugh- get postdoctoral experience, so in 1949 a regular visitor, Ed realized that beryl- ter Shelley, a physician at Stanford Uni- Ed went to Cornell University, where he lium-8, formed by fusion of two alphas, versity, in the statistical study of clinical stayed for almost 60 years. was metastable and would persist in trials; they were later joined by his With the publication in 1951 of the sufficient quantity to lead to carbon-12 grandson Nicholas Buckley. Bethe–Salpeter equation, which governs by fusion with a third alpha. Fred Hoyle After his participation in 1987 in the two-particle bound states in quantum then predicted that a resonance in 12C American Physical Society’s study of di- field theory, “Salpeter” became well rected energy missile defense technolo- known in theoretical physics. For most greatly enhances the probability of that final step. That work led the Royal gies, Ed became an outspoken critic of scientists, such early success would set the Strategic Defense Initiative. Re- the trajectory of their careers. Not Ed. He Swedish Academy of Sciences to award the Crafoord Prize to Hoyle and cently, with his second wife, Antonia soon decided that his talents and tem- Shouse, he fervently opposed the Bush perament were not well suited to quan- Salpeter in 1997. Among Ed’s many other critical con- administration’s use of torture. tum electrodynamics but rather to some At age 24, Ed had gone to Cornell, field, as he put it, “more controversial, tributions to astrophysics was his “initial mass function,” a simple power law where Bethe had assembled one of the more open-ended and new.” Thanks to world’s greatest physics departments, his interactions with Bethe, he came to that describes the number of stars of a given mass born from interstellar gas. with young members who would be- realize that nuclear astrophysics was come famous in popular culture. Within what he had been looking for. That concept has played a key role in numerous scientific areas; an interna- a few years, Ed demonstrated compara- For a while Ed pursued two paths: as ble intellectual powers. But he was a tional conference celebrated the func- an authority on high-precision atomic modest man who did not display his tion’s 50th ”birthday” in 2005. spectroscopy, including as coauthor depth and brilliance at first meeting. His While Ed was proudest of his 1955 with Bethe of a classic monograph, and amazing productivity always seemed paper on the initial mass function, dur- as an innovator in the “open-ended” incompatible with his relaxed de- ing his remarkably productive and ver- field of astrophysics. meanor, his role as the engaged father of satile career he had many other path- His first astrophysics paper, pub- a large extended family, his friendships lished in 1952, solved the great puzzle breaking accomplishments. He showed worldwide, and his endless zest for of what fueled red giants, stars that how electron screening affects thermo - travel, grand opera, and skiing. We have completed their burning of hydro- nuclear reaction rates and the equation count ourselves among the many who gen into helium. It was known that no of state of dense matter. Starting in the had the good fortune to be touched by stable nuclei would, via a sequence of 1960s, he turned from stars to ever- the truly remarkable life of Ed Salpeter. two-body reactions, lead from helium larger-scale phenomena: the physical Kurt Gottfried to carbon, and the probability of a direct chemistry of interstellar gas, galaxy ro- Saul Teukolsky three-alpha encounter was far too low. tational velocities and dark matter, and Ira Wasserman Using new data from William Fowler’s the development of galaxy clusters and Cornell University group at Caltech, where he had become superclusters. Ithaca, New York ᭿