Freeman Dyson
Visionary theoretical physicist who explored the morality of science and examined the possibility of extraterrestrial civilisations
FREEMAN DYSON, the British-born mathematician and physicist who has died aged 96, brought a deep moral sensibility to his understanding of the possibilities and dangers of scientific advance, though he was best known to the general public for his speculative work on the possibility of extraterrestrial civilisations.
A small, energetic man with sharp features frequently softened by a smile, Dyson first rose to public notice at the age of 24 when he showed that a number of seemingly incompatible theories of quantum electrodynamics (proposed by Richard Feynman, Julian Schwinger and Sin-itiro Tomonaga) which attempt to explain the interaction of electromagnetic radiation with matter, were not only reconcilable, but were in fact identical.
Equally important was Dyson’s work as an interpreter of science for the general public. His books included the autobiographical Disturbing the Universe (1979); Weapons and Hope (1984), a meditation on nuclear disarmament; and The Sun, the Genome, and the Internet (1999), a forward-looking review of the potential for good and ill of the most important technologies of the 21st century.
In each of these books Dyson was concerned not just to communicate the aesthetic beauty of science, but to explain the moral and theoretical issues involved in scientific endeavours ranging from nuclear research and space travel to solar power and genetic engineering.
In Disturbing the Universe, for instance, he provided a sympathetic yet critical account of the motivations of the chief architects of the atomic and hydrogen bombs, Robert Oppenheimer and Edward Teller, both of whom he had worked with in the 1950s. Oppenheimer, he claimed, was driven to build atom bombs by fear that if he did not seize this power, Hitler would seize it first. Teller was driven to build hydrogen bombs by the fear that Stalin would use this power to rule the world.
Oppenheimer, being Jewish, had good reason to fear Hitler. Teller, being Hungarian, had good reason to fear Stalin. But each of them, having achieved his technical objective, became convinced that he must have the political power to ensure that the direction of the enterprise he had created should not fall into hands that he considered irresponsible.
Much of Dyson’s popular appeal stemmed from his embrace of populist and often controversial positions, and he was in the forefront in arguing that scientists should move away from developing elitist “toys for the rich” to addressing the problems of the poor. In Imagined Worlds (1997) he regretted that “the pure scientists have become more detached from the mundane needs of humanity, and the applied scientists have become more attached to immediate profitability”.
Dyson always applied his conscience to his own work. One of his specialities was the field of adaptive optics, work with mirrors that could, in theory, allow a ground-based telescope to see objects as clearly in the sky as a space-based telescope. Before beginning this work, Dyson studied both the peaceful and the potential military applications and determined that the suggestion that such systems could be used to transmit “death rays” was more the stuff of science fiction than reality.
Dyson was no pessimist about the possibilities of science, and his freewheeling imagination enabled him to suggest new avenues for scientific inquiry. In one paper, he observed that it was possible that a growing technological society would increasingly surround its native star so as to maximise the capture of available energy.
The end point of this process, he suggested, would be the complete enclosure of the star, all wavelength from visible light downwards being intercepted and waste heat being radiated outwards as infrared radiation. Therefore, one method of searching for extraterrestrial civilisations would be to look for suspiciously large objects radiating in the infrared area of the electromagnetic spectrum – a concept which has come to be known as the “Dyson sphere”.
He went on to imagine an artificial biosphere or environment in which life could exist – a vast structure built by dismantling a Jupiter-sized planet and using the raw material to provide a living area millions of times greater than that of any planet.
He further suggested that the powerful gravitational field of a white-dwarf binary star might serve as a super-slingshot to accelerate interstellar voyagers free of fuel costs, and that an army of self-reproducing automata could mine the ice of
Saturn’s moons and use it to make Mars a garden planet. His colleagues coined the term “Dysonian” to describe “ideas that crackle with originality”.
Freeman John Dyson was born at Crowthorne, Berkshire, on December 15 1923 into an intensely musical family. His father, the composer and conductor Sir George Dyson, eventually became the director of the Royal College of Music.
Dyson’s boyhood home lacked scientific influences until the family adopted one in the form of Sir Frank Dyson, Astronomer Royal. He was no relation to the Berkshire Dysons, but was from the same part of Yorkshire as Sir George. In his book From Eros to Gaia (1992), Freeman Dyson recalled that breakfast-table discussions about Sir Frank’s exploits influenced his early interest in astronomy and spurred him as an eight-year-old to write a novel based on him.
The unfinished manuscript of Sir Phillip Robert’s Erolunar Collision was at once a snapshot of the astronomical events of 1931 and an indicator of Dyson’s future interests. In 1931, the orbit of asteroid Eros was going to pass close to the Earth, providing an opportunity for astronomers to get an accurate reading of the distance between the Earth and the sun.
In Dyson’s novel, Sir Phillip, director of the British South African Astronomical Society, successfully predicts a collision between Eros and the moon by calculating the orbit of Eros 10 years and 285 days in advance. He decides to land astronomers on the moon’s surface to witness the collision. But, in the final pages, he is left struggling to raise funds and design a spacecraft.
Dyson went to Winchester, where his father was then director of music, and developed a passion for mathematics. His maths studies at Cambridge were interrupted in 1943 when he was called up to work in the operational research section of RAF Bomber Command, a role he took only after giving serious consideration to being a conscientious objector. Back at Cambridge, he took his degree in 1945.
In 1947 he won a Commonwealth Fund Fellowship to study physics in America and spent the next two years at Cornell University under Hans Bethe, a future Nobel laureate who had spent the war years working on the Manhattan Project.
Bethe brought other former Los Alamos scientists to Cornell, including Richard Feynman, a young professor of physics who would help influence the course of Dyson’s career. From Cornell, Dyson moved to Princeton, where he studied under Robert Oppenheimer.
It was during this time that he gained the attention of the scientific community by taking the various theories of quantum electrodynamics advanced by Feynman, Schwinger, and Tomonaga, and synthesising them into a single unified theory. The idea came to him, he said, while he was taking a Greyhound bus ride across Nebraska.
He returned to Britain in 1949 to become a research fellow at Birmingham University. But two years later he was appointed professor of physics at Cornell and left Britain for good. In 1953 he accepted a professorship of physics at the Institute for Advanced Study at Princeton.
In 1956 he moved to the General Atomic Division of the General Dynamics Corporation, working with Edward Teller, inventor of the hydrogen bomb, on developing a small nuclear reactor which would incorporate the highest possible safety features. Known as Triga, the reactor produces short-lived isotopes for diagnostic medicine, and continues in production today.
Dyson became an American citizen in 1957, the year the Soviet Union launched Sputnik and the space race. In 1958 Dyson joined the Orion Project as chief theoretician for propulsion systems for a nuclear-powered spaceship which, it was hoped, would send a man to Mars. A prototype was demonstrated using conventional explosives and Dyson went so far as to predict that man would reach Mars by 1965 and Saturn by 1970.
Unfortunately, Orion met the same fate as Sir Phillip Robert’s fictional mission to the moon, though Dyson himself was partly responsible. In the early 1960s he had become a staff member of the American Arms Control and Disarmament Agency, and took part in test ban negotiations; he also served as chairman of the Federation of American Scientists, an organisation founded in 1945 by former Manhattan Project scientists, in order to address the dangers and implications of the nuclear age. It was the 1963 Nuclear Test Ban Treaty which caused the Orion project to be abandoned in 1965.
From the mid-1960s Dyson turned to writing, first scientific texts such as Symmetry Groups in Nuclear and Particle Physics (1966) and Neutron Stars and Pulsars (1971). But in 1979, in Disturbing the Universe, he addressed the general public, winning an American Book Award nomination.
Weapons of Hope (1984), a study of ethical problems of war and peace, won the National Book Critics Circle award for general non-fiction; Infinite
in All Directions (1988) was a philosophical meditation based on a series of lectures on natural theology; Origins of Life (1985) discussed one of the major unsolved problems of science. The Sun, the Genome, and the Internet (1999) explored the question of whether new technologies could be used to narrow the gap between rich and poor.
Dyson won countless honours and awards for his scientific work and for his contributions to the public understanding of science. He was elected a Fellow of the Royal Society in 1952, winning the society’s Hughes Medal in 1968. He became a Fellow of the American National Academy of Sciences in 1964, and was awarded the Max Planck Medal of the German Physical Society in 1969, the J Robert Oppenheimer Memorial Prize in 1970, the Israeli Harvey and Wolf Prizes (1977 and 1981) and the Enrico Fermi Award given by the US Department of Energy in 1995. In 2000 he was awarded the Templeton Prize for progress in Religion.
Dyson’s first marriage, to the mathematician Verena Huber, was dissolved. He married, secondly, in 1958, Imme Jung. She and their four daughters, together with a son and daughter of his first marriage, survive him.
Freeman Dyson, born December 15 1923, died February 28 2020