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On Freeman Dyson

Freeman Dyson’s response to the perplexity of our existence was not purely scientific. A polymath by nature, he responded deeply to art and literature and often framed life’s dilemmas through their lens. Always thinking of himself as a mathematician first, he unified quantum electrodynamics and saw the Nobel Prize go to the three who had formulated, in different ways, its structure, but he would cast himself as the Ben Jonson to Richard Feynman’s Shakespeare, a fact noted by Gregory Benford in his review of Phillip F. Schewe’s recent biography. That would be a typical allusion for a man whose restless intellect chafed at smug over-specialization, something neither he nor Feynman could ever be accused of.

Feynman, Julian Schwinger and Shinichiro Tomonaga each came up with ways to describe how electrons and photons interrelate, but it was Dyson, on one of his long cross-continental bus trips, who worked out the equivalence of their theories, giving us QED. He would publish the unifying paper in Physical Review in 1949. A year later, he met Tomonaga at Princeton, describing him in a June 24, 1950 letter to his parents as “a charming man, like so many of the really good ones. He talked with me for three hours with much humour and common sense… I have the impression that he is an exceptionally unselfish person.”

Which is exactly the impression I had of Dyson in the one interaction (other than email) I had with him, back in 2003 while I was pulling together material for Centauri Dreams and called the Institute for Advanced Study, his scholarly home since 1953, to schedule an interview. It was a spring day and, unfortunately for my purposes, a loud lawn mower was moving up and down outside Dyson’s window. I was having to shout to be heard, a nuisance, and I had trouble hearing him, but we persisted with much repetition and his good humor.

Always associated with Project Orion, the dramatic concept to propel a spacecraft by exploding nuclear charges behind it, Dyson had moved away from the idea, and indeed from nuclear energy entirely. He wanted to talk about microwave and laser propulsion, and expressed an interest in Clifford Singer’s ideas on pellet streams, an idea he liked because of the lack of diffraction. Over a close pass by the outside lawnmower, I heard him clearly: “Nuclear energy doesn’t cut it! Nuclear energy is too small. You’re using less than one percent of the mass with any kind of nuclear reaction so you’re limited to less than a tenth of lightspeed. Nuclear is great inside the Solar System, but not very interesting outside of it.”

If you would know something of this man, of his values and his conception of life, I direct you to the splendid Maker of Patterns: An Autobiography Through Letters, published in 2018. The concept is daring, for by eschewing standard autobiography to present himself largely through letters he wrote at the time, Dyson gives up the opportunity to edit his persona. None of us can point to a lifetime without contradiction, which is just another way of describing growth. Dyson was willing for that growth to be in full view. Thus the Dyson of 1958, writing about the Project Orion work he would later discount:

The basic idea is absurdly simple. One is amazed that nobody thought of it before. But the only man who could think of it was somebody who had been working and thinking for years with bombs, so that he could know exactly what a bomb of a given size will do. It was not an accident that this man happened to be Ted [Taylor]. The problem is to convince oneself that one can sit on top of a bomb without being fried… Ted’s genius led him to question the obvious impossibility. For the last six months Ted has spent his time talking to people in the government and trying to convince them that this idea is not crazy. He has had a hard time. But it seems we have now a lot of influential people on our side… Ted and I will fly to Los Alamos this evening. We travel like Paul and Barnabas.

Nothing would come of these travels, of course, because of the signing of the Limited Nuclear Test Ban Treaty of 1963, though Dyson would later support the treaty amid his deep concern over nuclear destruction. The idea of Orion still tantalizes many interstellar advocates today.

The lack of self-justifying ego — so rare in all too many quarters — that informs Dyson’s writings informs his wide reach into non-scientific markets, where he became the eloquent explainer of concepts he worked with in the course of his long life. I doubt there are many Centauri Dreams readers who do not have at least a few of his titles, books like Disturbing the Universe (1981) and Infinite in All Directions (1988). So many concepts sprang from his insistence on seeing things from a cosmological perspective, including for our interstellar purposes the Dyson sphere and the biological, self-replicating probe called ‘astrochicken’ that was enabled by artificial intelligence.

Image: Around the table clockwise are Dyson, Gregory Benford, Jim Benford and David Brin. Taken Jan. 30, 2019, before a discussion between Greg and Dyson at the Clarke Center (available here on YouTube).

All of these concepts he could relate to the general public through a style that was at once clear and enabling, so that the reader would, like this one, often look up from his or her reading to take in the audacity of ideas that were as logical as they were innovative. The archives of this site are awash with references to Dyson’s contributions, a tribute to his range and his reach. Remarkably, that intellect never deserted him even as his physical strength began to fail. Jim Benford, who has known Dyson since the 1960s, told me on the day of Dyson’s death that he had continued his yearly trips across the country to his La Jolla (CA) residence up until last year. This time around, at 96, he told Jim his doctors had argued against it. He would die a week later, a loss as deep to this field as his contribution was rich.

We shall know what we go to Mars for only after we get there. The study of whatever forms of life exist on Mars is likely to lead to better understanding of life in general. This may well be of more benefit to humanity than irrigating ten Saharas. But that is only one of many reasons for going. The main purpose is a general enlargement of human horizons.

Thus Dyson in a letter from La Jolla in 1958. Really, you must read Maker of Patterns. And from my 2003 interview with him:

Look at how people spread around the Earth. It’s not clear why we want to travel so much, but we do. It seems to be characteristic of humans from the time we left Africa. Why do people leave Africa to spread out to all these desolate places, to Siberia and across the Pacific? We know that people just do this. It’s part of human nature…

I think of him foremost as a deeply sane man, one who saw both the aspirations of the human mind as well as its limitations and took on the challenge of explaining life’s mysteries with a fierce joy. No one who reads, and re-reads, his essays and papers can miss this affirmation of mind at work, always building in new directions, unifying, shaping, questioning. It would be superfluous to try to summarize his many accomplishments in one post, for we will, inevitably, be turning his ideas over in our discussions for the rest of the lifetime of Centauri Dreams.


Comments on this entry are closed.

  • James Benford March 2, 2020, 15:27

    The photo of the four of us was taken last year, Jan. 30, 2019, before the discussion between Greg & Freeman at the Clarke Center, which is on YouTube.

    • Paul Gilster March 2, 2020, 17:12

      Now corrected, and I’ve added the YouTube link to the talk. Thanks!

  • Gregory Benford March 2, 2020, 15:44

    Dyson spheres came from this:
    Resolved to pursue the adventure of life and of spirit in the cosmical, the widest of all spheres, it was in constant telepathic communication with its fellows; and at the same time, conceiving all kinds of strange practical ambitions, it began to avail itself of the energies of its stars upon a scale hitherto unimagined. Not only was every solar system now surrounded by a gauze of light traps, which focused the escaping solar energy for intelligent use, so that the whole galaxy was dimmed…
    From Star Maker, by Olaf Stapledon.
    Published by Methuen in 1937

  • James Jason Wentworth March 3, 2020, 2:18

    As a person, I found Freeman Dyson’s emotional intensity to be, like Baby Bear’s porridge, “just right.” In a 1993 television discussion titled “A Glorious Accident” (the whole ~3-1/2 hour get-together of several scientists—with fine food and wine served, too!—as well as excerpts of it, can be seen here: https://www.youtube.com/results?search_query=Rupert+Sheldrake+Stephen+J.+Gould+Freeman+Dyson ), Freeman Dyson made an important point with a wordless gaze of just the right type and force–sufficient for the purpose, but no stronger:

    At one point Rupert Sheldrake, another member of the gathering, was being ridiculed for his ideas about homing pigeons and morphic resonance. While this was happening, Freeman Dyson did something that I found very morally admirable—he looked at the “ridiculer” with an expression of disapproval (but not anger) that said, “Do you ^have^ to belittle those you disagree with, and disagree so disagreeably?” He could have looked away or looked down, but he didn’t, and I was so gratified to see him do that, as I’m sure the whole audience noticed it.

  • ljk March 3, 2020, 15:00

    Freeman Dyson remembered by people who knew him: “an unusual visionary”

    Colleagues reflect on the life and work of the renowned physicist, who died last week.

    by Edward Witten, Dwight Neuenschwander, Harold Feiveson, Arthur Jaffe, and Elliott Lieb

    March 2, 2020

    Freeman Dyson, who died on Feb 28 at the age of 96, was an intellectual giant and well-regarded as a physicist, mathematician and public intellectual—and also as a mentor, grandfather and friend. Technology Review asked a number of his colleagues to reflect on his life and work. These are some of the responses; more will be added in coming days.


  • Harold Shaw March 3, 2020, 22:33

    What would Freeman Dyson have done with all the power of a star? I won’t make a case for heaven, but if it is so I hope he gets the chance. Even if his visions of mega-structures doesn’t prove “true” or optimal, he showed us how to think about navigating Deep Time.

  • wdk March 3, 2020, 22:40

    Whether it is within the aerospace, astrophysics or physics community, there is widespread feeling to observe the passing of Freeman Dyson. While living and speaking rather quietly, it is remarkable how much of an impression he made on so many of us.

    Maybe a year or two ago, at one of the neighborhood used book store, I couldn’t resist purchasing an old Dover paperback that I knew I would never be able to read or comprehend, but just had to have. Perhaps it was a premonition.
    “Selected Papers on Quantum Electrodynamics”, Edited by Julian Schwinger , Nobel Laureate.
    34 selected papers by…
    …Fermi, Heisenberg, Dirac, Oppenheimer, Rutherford, …Pauli, Bethe, Schwinger, Tomonaga, Feynmann, Wigner…
    On the cover it ran out of space before it mentioned the two papers by F. J. Dyson in the table of contents:
    24. The Radiation Theories of Tomonaga, Schwinger and Feynmann
    25. The S Matrix in Quantum Electrodynamics.
    The editor made some notes about the chronological order of the papers.
    The 24th paper was submitted to Physical Review in 1948 began with the following abstract.

    “A unified development of the subject of quantum electrodynamics is outlined, embodying the main features both of the Tomonaga-Schwinger and of the Feynmann radiation on higher order radiative reaction s and vacuum polarization phenomena. However, the theory of these higher order processes is a program rather than a definite theory, since no general proof of the convergence of these effects is attempted.

    “The chief results obtained are (a) a demonstration of the equivalence of the Feynmann and Schwinger theories , and (b) a considerable simplification of the procedure involved in applying the Schwinger theory to particular problems, the simplification being the greater the more complicated the problem.

    Supposedly, this paper was the result of reflections occuring on a bus trip, hitting him around Omaha in his twenties. They would alter his life and many others. Maybe even the people he mentioned.

    From time to time a few decades back, would read excerpts of Dyson’s forthcoming books in the New Yorker – and then bought a couple. His books were always worth the read, illuminating about his life or significant events of the 1940s in England, New Mexico and the Manhattan project; eventually life at Princeton within its physics community. And before that there was the book about him and his son, “The Starship and the Canoe”, recounting Dyson’s years pursuing a nuclear powered spaceship design in San Diego – and his son’s adventures in British Columbia with a treehouse aloft in a Douglas fir and building a canoe as correspondingly ambitious as his father’s plans for space. In between, Dyson’s speculations about civilizations over our heads or beyond our telescopic view were like nothing seen in science fiction befo;re e.g., about neutron stars he would go so far as to conjecture how life could exist on their surfaces; fast, furious and tiny. Flat, at any rate.
    Finally, after the 1970s and 80s, I did get to meet him a couple of times. Attended a couple of the Space Studies Institute conferences at Princeton back in 96 and 97 or something like that – and gave a couple of papers the second time. The Space Studies Institute was based at Princeton and Freeman Dyson headed that institute as well as being a member of the Institute for Advanced Studies staff. One of my papers was about using the External Tank on orbit, and how it could be stabilized with a magnetic damper. ET discussions always brought out enthusiasts, so there was a lot of discussion later. But a highlight for me was the fact that Freeman Dyson was out there in the audience in a front row. As far as I know, the most distinguished individual to whom I ever had the opportunity to give a talk. Outside the auditorium we only talked briefly while I was there during the cocktail party portion. Mostly he was telling me about some features of various star systems or stars – but I can’t recall now what that was about, even if I had a ginger ale. What was easier to remember was his faith that the New Jersey skunk cabbage was bound to be a boon for Martian settlers. Growing up in NJ, sometimes I would walk a shortcut to school, down a railroad track back in a woods that was full of them. Skunk cabbage sprouted before winter was over and were resistant to freezing.
    Off the book shelves I located “Infinite in All Directions”, but I haven’t yet located “Disturbing the Universe”, which is where, I believe, his accounts of the 1940s are. More recently, Dyson had published much of his correspondence in lieu of an autobiography.
    It was Saturday when I discovered that Freeman Dyson had passed away. I had picked up the NYT at a news rack.
    “After finishing high school at Winchester College where his father taught music, he entered the University of Cambridge, Trinity College, and excelled in mathematics.
    “Looking for a way to serve the war effort while satisfying his pacifist leanings, he took leave in 1943 to work as a civilian scientist for the Royal Air Force Bomber Command…”

    I recall his writing in “Disturbing the Universe” and elsewhere that he did have misgivings about those years: for both the crews dispatched on those missions and the terrible costs it had on people below them. After the war, he did return to Cambridge and concentrated on becoming a physicist. He then came to the United States and entered graduate study at Cornell, studying with Hans Bethe – and working with Richard Feynmann. His accounts of people associated with the Manhattan Project seemed to suggest to me that he spent much time in New Mexico. Probably it was while he was working closely with Bethe and Feynmann after the war.
    As the article goes on to say, Feynmann, Julian Schwinger at Stanford and Sinitoro Tomonaga in Japan were all working on descriptions of the behavior of electron – photon and positron interactions – and Dyson found a way to describe their theories in a mathematically integrated manner, showing that they were equivalent, consistent even with the constraints imposed by relativity and quantum mechanics (quantum electrodynamics), publishing his results in 1949. Perhaps ironically, the three aforesaid physicists were awarded the Nobel Prize in 1965. Dyson moved on to the Princeton Institute of Advanced Study in 1953, remaining on staff. Freeman Dyson was also a regular adviser to the US government on science matters, often with a group known as the Jasons, a group which has even become involved in propellantless propulsion studies.

    In the space community, Dyson was known for his speculations about extra terrestrial civilizations and their possible mark, e.g., the Dyson sphere. Of late, thanks to the Kepler mission and other observations, at least one star was named as a suspect site, ( “Tabitha’s”), likely something for another story.

    Several times, evidently, Dyson has delivered wide ranging lectures which were published later in book form. The NYT obituary mentions the Templeton lecture. “Infinite in All Directions” is another example, the Gifford lectures in Aberdeen, Scotland, delivered in 1985.

    Freeman Dyson was very individual in the scientific community. It might be on account of differences from country to country that Dyson never bothered with obtaining a doctoral degree. He found comfort in both cosmology and his religious convictions. In other words, that despite what others might perceive as randomness or no purpose, he conveyed a message that there was purpose in the universe, if you will, in its genesis; and it was good.

  • Kelvin F Long March 9, 2020, 11:34

    Hi all,
    So awful to hear this news. He was a massive loss to this field and physics in general. My own memories of him are captured in my short article here:


    Kelvin F Long

  • wdk March 9, 2020, 19:55

    Thank you for that link. Very much appreciated.

  • ljk July 1, 2020, 14:18


    [Submitted on 30 Jun 2020]

    Dyson Spheres

    Jason T. Wright

    I review the origins and development of the idea of Dyson spheres, their purpose, their engineering, and their detectability. I explicate the ways in which the popular imagining of them as monolithic objects would make them dynamically unstable under gravity and radiation pressure, and mechanically unstable to buckling.

    I develop a model for the radiative coupling between a star and large amounts of material orbiting it, and connect the observational features of a star plus Dyson sphere system to the gross radiative properties of the sphere itself. I discuss the still-unexplored problem of the effects of radiative feedback on the central star’s structure and luminosity.

    Finally, I discuss the optimal sizes of Dyson spheres under various assumptions about their purpose as sources of low-entropy emission, dissipative work, or computation.

    Comments: Invited review. 21pp, 1 figure

    Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

    Journal reference: Serbian Astronomical Journal 200 (2020) 1-18

    DOI: 10.2298/SAJ2000001W

    Cite as: arXiv:2006.16734 [astro-ph.EP]
    (or arXiv:2006.16734v1 [astro-ph.EP] for this version)

    Bibliographic data

    [Enable Bibex (What is Bibex?)]

    Submission history

    From: Jason Wright [view email]

    [v1] Tue, 30 Jun 2020 12:45:18 UTC (157 KB)