Freeman Dyson (1923–2020)

Obituary Freeman Dyson (1923–2020)

Nuclear physicist, polymath, disarmament pioneer and government adviser.

reeman Dyson’s influence spanned creation of energy-capturing solar arrays physics, nuclear disarmament, poli- stationed around distant stars (F. J. Dyson tics, culture and even science fiction. Science 131, 1667–1668; 1960). These ‘Dyson While still a student, he provided the spheres’ became fuel for dozens of sci- mathematical grounds for quantum ence-fiction stories, and featured in an episode Felectrodynamics, or QED, to explain the of the television show Star Trek. interactions of elementary particles. In 1963, Dyson introduced field theory into the study as chairman of the Federation of American of condensed-matter physics in the mid-1950s. Scientists, he helped to craft the Partial Test In the 1960s, he helped to pioneer the use of Ban Treaty, which has largely kept nuclear matrices of random variables to describe a detonation debris out of the air and ocean. system’s condition in nuclear and solid-state In 1967, he and fellow members of JASON, an physics; mathematically proved the stability independent consortium of scientists advis- of solid matter; and studied the possibility that ing the US government, successfully argued fundamental constants of nature change over against the use of tactical nuclear weapons in time. He was the first to provide a detailed sci- the Vietnam War. The report was one of many entific description of the very late Universe he co-authored over his 50 years as a JASON. and he argued that metabolism and replication Dyson died on 28 February, aged 96. might have evolved separately in primitive liv- Dyson was born in Berkshire, UK, and his ing organisms. mathematical skills saw him advance quickly at In his first book for the public, Disturbing the school and later at the University of Cambridge Universe (1979), he stressed the need for both and in Bomber Command during the Second science and the sublime. Scientific models SAURO/NYT/REDUX/EYEVINE World War. In 1947, he became a graduate were just part of humanity’s way of viewing the

student of the nuclear physicist Hans Bethe cosmos and understanding the complexities WILLIAM E. at Cornell University in Ithaca, New York. applications. Its fuel elements contained a of our own species. Art, religion and historical There, he advanced understanding of the temperature-dependent component; if the study were all vitally important, too, he argued. subtle interactions between electrons and core got too hot, neutron absorption would His most conspicuously contrarian views the electromagnetic field. drop, cutting off fission reactions. This design were on climate change. Although not denying He spent the spring semester in almost daily proved to be one of the most popular reactor that rising atmospheric levels of carbon diox- contact with Richard Feynman, and studied for types ever devised. At General Atomic, Dyson ide would alter global temperature and vege- six weeks with Julian Schwinger at a summer later helped to design a nuclear-bomb-powered tation, he thought that many of the changes school in Michigan. Feynman and Schwinger space rocket: the Orion propulsion system. For would be beneficial. Furthermore, he argued went on to share a Nobel prize for their work that models were not sufficiently precise to on QED. Dyson’s QED work brought together “He stressed the need for both justify multi-billion-dollar technology ‘fixes’, Feynman’s diagrams and Schwinger’s field such as the elimination of fossil fuels. The model. In 1948, too prodigious to continue science and the sublime.” money would be better spent, he contended, as a student, Dyson moved to the Institute combating hunger, illiteracy and disease. for Advanced Study (IAS) at Princeton in New a very brief period (and perhaps never seri- He was supreme at two things, he said: Jersey. There, bombarded by the caustic com- ously), it was a rival for the chemical-based mathematical calculations and writing. Others ments of director J. Robert Oppenheimer, who rockets being developed by the nascent NASA. would add to those his graciousness and tol- disliked the new theory, Dyson worked out the In the early 1970s, he and his collaborators erance. He was a frequent speaker and book final touches of his QED model. He won over proposed ways to reduce the blurring effect reviewer, notably for the New York Review of Oppenheimer and published his results, and of atmospheric turbulence while tracking Books, but avoided collaboration, saying that job offers poured in. missiles (and eventually galaxies), by quickly he needed the freedom to vary his interests. Dyson spent most of the rest of his career at adjusting mirror facets. This system, now All his views, the ortho- and the heterodox, the IAS. When he was unable to extend QED to called adaptive optics, is a feature of most were concerned with the future of the human explain the forces in the nucleus, he realized large optical telescopes. species. He felt that humans would eventually that his curiosity and abilities would be better Dyson was one of the first proponents of a migrate to permanent colonies in space — for deployed across a variety of topics. This intel- scientific approach to the search for extrater- him an exciting prospect. This long view of lectual restlessness resulted in a blizzard of restrial intelligence. In a paper published in humanity might be Dyson’s most lasting legacy. cross-disciplinary accomplishments. 1960, he proposed scanning infrared rather In 1956, working with physicist Edward than radio wavelengths, because heat emis- Phillip F. Schewe is a physicist and author Teller at the private company General Atomic sions would be a more likely indicator of life. of Maverick Genius, a biography of near San Diego, California, Dyson designed an As one example of how an advanced civiliza- Freeman Dyson. ‘intrinsically safe’ nuclear reactor for research tion could operate, this paper described the e-mail: [email protected]