Freeman Dyson’s Advice to a College Freshman
Anyone who ever had the pleasure of talking to Freeman Dyson knows that he was a gracious man deeply committed to helping others. My own all too few exchanges with him were on the phone or via email, but he always gave of his time no matter how busy his schedule. In the article below, Colin Warn offers an example, one I asked him for permission to publish so as to preserve these Dysonian nuggets for a wider audience. Colin is an Associate Propulsion Component Engineer at Maxar, with a Bachelor of Science in mechanical engineering from Washington State University. His research interests dip into in everything from electric spacecraft propulsion to small satellite development, machine learning and machine vision applications for microrobotics. Thus far in his young career, he has published two papers on the topics of nuclear gas core rockets and interstellar braking mechanisms in the Journal of the British Interplanetary Society. He tells me that when he’s not working on interstellar research, he can be found teaching music production classes or practicing martial arts.
by Colin Warn
Three years ago, I decided to make a switch from being a part time dance music ghost producer to study something that would help advance humanity’s knowledge of the stars. Eventually, I decided that something would be mechanical engineering, a switch which was in no small part due to space podcasts that introduced me to cool technologies such as Nuclear Pulsed Propulsion (NPP): Rockets propelled by small mini-nuclear explosions. The man behind this technology? Freeman Dyson.
Dyson worked on Project Orion for four years, deeply involved in studies that produced the world’s first and only prototype spacecraft powered by NPP. Due to the 1963 Partial Test Ban Treaty, which he supported, humanity’s best bet for interstellar travel was filed away. Yet, something about the audacity of this project resonated with me decades later when I uncovered it, especially when I found out that Dyson was in charge of this project despite not being a PhD.
So, as a bright-eyed and optimistic freshman entering his first year of college, figuring that out of anyone in the world he would have the best insights on what technology would lead humanity to the stars, I decided to send him this email:
Hello Professor Dyson,
My name is Colin Warn, and I’m a freshman pursuing a degree in mechanical engineering/physics.
Had a few questions for you regarding how I should structure my career path. My ambitions are to work on interstellar propulsion technologies, and I figured you might know a thing or two about the skill set required.
If you have the time, here’s what I’d love to hear your opinion on:
1. What research/internships would you suggest I focus on as an undergraduate to learn the skills that will be needed for working on advanced propulsion technologies? Especially in my freshman and sophomore years?
2. For my initial undergrad years, would you suggest that I focus more on taking physics or engineering courses initially?
Thank you so much in advance for your time. Been reading the book your son wrote about Orion. Let’s just say the reactions I’ve been getting from my friends when I tell them what I’m reading about is already quite fun to observe.
Regards,
-Colin
I sent it to his Princeton email, as I’ve sent many emails in the past to fairly high-caliber people, without a hope of getting anything in return.
Two days later, I woke up to find this email in my inbox.
Dear Colin Warn,
I will try to answer your two questions and then go on to more general remarks.
1. So far as I know, the only techniques for interstellar propulsion that are likely to be cost-effective are laser-propelled sails and microwave-propelled sails. Yuri Milner has put some real money into his Starshot project using a high-powered laser beam. Bob Forward many years ago proposed the Starwisp spacecraft using a microwave beam. Either way, the power of the beam has to be tens of Megawatts for a miniature instrument payload of the order of a gram, or tens of Terawatts for a human payload of the order of a ton. My conclusion, the manned mission is not feasible for the next century, the instrument mission might be feasible.
For the instrument mission, the propulsion system is the easy part, and the miniaturization of the payload is the difficult part. Therefore, you should aim to join a group working on miniaturization of instruments, optical sensors, transmitters and receivers, navigation and information handling systems. These are all the technologies that were developed to make cell-phones and surveillance drones. An interstellar mission is basically a glorified surveillance drone. You should go where the action is in the development of micro-drones. I do not know where that is. Probably a commercial business attached to a technical university.
2. For undergraduate courses, I would prefer engineering to physics. Some general background in physics is necessary, but specialized physics courses are not. More important is computer science, applied mathematics, electrical engineering and optics, chemistry of optical and electronic materials, microchip engineering. I would add some courses in molecular biology and neurology, with the possibility in mind that these sciences may be the basis for big future advances in miniaturization. We still have a lot to learn by studying how Nature does miniaturization in living cells and brains.
This email contained more detailed insights to my questions than I could have ever hoped for. Then to top it all off, he still had one more piece of advice for me to a question I hadn’t even asked.
General remarks. In my own career I never made long-range plans. I would advise you not to stick to plans. Always be prepared to grab at unexpected opportunities as they arise.Be prepared to switch fields whenever you have the chance to work with somebody who is doing exciting stuff. My daughter Esther, who is a successful venture capitalist running her own business, puts at the bottom of every E-mail her motto, “Always make new mistakes”. That is a good rule if you want to have an interesting life.
With all good wishes for you and your career, yours sincerely,
Freeman Dyson.
Upon reading this email in 2018, I promised myself that one day I’d put myself in a position to thank him in person. Sadly I’ll never get the opportunity. I discovered watching an old YouTube video featuring him that he died in February of 2020.
So this article is my way of saying thank you to him. For creating literal star-shot projects to inspire a new generation. For being someone who always questioned the status quo. But most of all, for still being down to earth enough to email some amazingly insightful answers to a freshman’s cold-email. I hope one day I’m in a position where I can pass on the favor.
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.
Freeman Dyson: Reasons for Optimism
Centauri Dreams believes profoundly in what I might call ‘realistic optimism.’ While an aggressive belief in the human future can be overstated, it’s important to remember that intellectual fashions come and go, leaving many a futurist trying to explain another failed prediction. The view here is that the vast problems that face our species are solvable through common sense and technology, and that somehow we will engage our tools to get us off-planet before we annihilate ourselves.
Playing into this notion is the work of David Haussler, cited recently by Freeman Dyson as one reason for his own deeply optimistic view of the future. Studying the human genome, Haussler and team at UC Santa Cruz discovered a section of DNA called Human Accelerated Region 1. HAR1 evidently shows up in the genomes of a wide range of species, from mouse to chicken to chimpanzee. It was apparently unchanged for about three hundred million years, as Dyson told Benny Peiser in a recent interview (see this New Scientist story for more on HAR1).
Dyson notes that this unusual patch of DNA is considerably modified in the human genome, with eighteen known mutations. That means that as we move from the common ancestor of chimpanzees and humans to our species today, HAR1 seems to represent a key difference between humans and other mammals. Dyson sees it as wrapped up in the evolution of the human brain, and that’s good news because the more we understand what drives us, the more we can do about it.
Listen to Dyson relating HAR1 to the work of a man he deeply admired:
I am optimistic because I see the discovery of HAR1 as a seminal event in the history of science, marking the beginning of a new understanding of human evolution and human nature. I see it as a big step toward the fulfilment of the dream described in 1929 by Desmond Bernal, one of the pioneers of molecular biology, in his little book, The World, the Flesh and the Devil: An Enquiry into the Future of the Three Enemies of the Rational Soul. Bernal saw science as our best tool for defeating the three enemies. The World means floods and famines and climate changes. The Flesh means diseases and senile infirmities. The Devil means the dark irrational passions that lead otherwise rational beings into strife and destruction. I am optimistic because I see HAR1 as a new tool leading us toward a deep understanding of human nature and toward the ultimate defeat of our last enemy.
My own optimism holds that we will develop the technologies to maintain a large human presence in space in a variety of habitats. And of course the hope is that we will gradually expand outwards — either as humans adapting to living in the vacuum (Dyson sees this happening) or through highly developed artificial intelligence — to the stars themselves. With more than enough external threats from our own environment and nearby space to keep us busy, losing the fear of annihilation from our flawed human nature would be a major step in this direction. If Dyson is right, such a goal may emerge from our studies of the genome.
On Retrieving Dyson
One of the pleasures of writing and editing Centauri Dreams is connecting with people I’ve been writing about. A case in point is my recent article on Freeman Dyson’s “Gravitational Machines” paper, which has only lately again come to light thanks to the indefatigable efforts of David Derbes (University of Chicago Laboratory Schools, now retired). See Freeman Dyson’s Gravitational Machines for more, as well as the follow-up, Building the Gravitational Machine. I was delighted to begin an email exchange with Dr. Derbes following the Centauri Dreams articles, out of which emerges today’s post, which presents elements of that exchange.
I run this particularly because of my continued fascination with the work and personality of Freeman Dyson, who is one of those rare individuals who seems to grow in stature every time I read or hear about his contributions to physics. It was fascinating to receive from Dr. Derbes not only the background on how this manuscript hunter goes about his craft, thereby illuminating some of the more hidden corners of physics history, but also to learn of his recollections of the interactions between Dyson and Peter Higgs, whose ‘Higgs mechanism’ has revolutionized our understanding of mass and contributed a key factor to the Standard Model of particle physics. I’m also pleased to make the acquaintance of a kindred spirit, who shares my fascination with how today’s physics came to be, and the great figures who shaped its growth.
by David Derbes
I have a lifelong interest in the history of physics, particularly the history of physicists. Somehow I got through graduate school (in the UK; but I’m American) with only a very shaky acquaintance with Feynman diagrams and calculations in QED [quantum electrodynamics, the relativistic quantum theory of electrically charged particles, mutually interacting by exchange of photons]. This led me to a program of self-study (resulting in “Feynman’s derivation of the Schrödiinger equation”, Amer. Jour. Phys. 64 (1996) 881-884, two editions of Dyson’s AQM [Advanced Quantum Mechanics], and, with Richard Sohn, David J. Griffiths, and a cast of thousands, Sidney Coleman’s Lectures on Quantum Field Theory).
Along the way I stumbled onto David Kaiser’s Drawing Theories Apart, a sociological study of Feynman’s diagrams. Kaiser, who is now a friend, is a very remarkable fellow; he has two PhD’s, one in physics ostensibly under Coleman but actually under Alan Guth, and another in the history and philosophy of science). Kaiser mentioned the Cornell AQM notes of Dyson, never published, and I thought, hmmm… I found scans of them online at MIT, and (deleting a few side trips here) contacted Dyson about LaTeX’ing them for the arXiv (where they may be found today).
Image: Physicist, writer and teacher David Derbes, recently retired from University of Chicago Laboratory Schools. Credit: Maria Shaughnessy.
Dyson was quite enthusiastic. It probably helped that I had been a grad student of Higgs’ under Nick Kemmer at Edinburgh; Kemmer had steered Dyson towards physics and away from mathematics at Cambridge after the war. Ultimately (in my opinion) it is Dyson who was (very quietly) responsible for the recognition of Higgs’s work, and its incorporation by Weinberg into the Standard Model. Dyson had seen Higgs’s short pieces from 1964, learned (maybe from Kemmer) that he was at UNC Chapel Hill for 1965-66, wrote Higgs to give a talk at the IAS, which led to his giving a talk to Harvard (with Coleman, Glashow, and maybe Weinberg, then at MIT, in the audience).
Typing up Dyson’s Cornell lectures killed two birds: I learned more about QED, and I learned LaTeX from scratch. In retirement, “manuscript salvage” is my main hobby. (There are at least a couple of other oddballs who are doing much the same thing: David Delphenich, and there’s a guy in Australia, Ian Bruce, who has done a bunch of stuff from the 17th and 18th century, among other things a new translation of the Principia.)
Flash forward to shortly after LIGO’s results were announced. A letter in Physics Today drew attention to Dyson’s “Gravitational Machines”, so I went looking for it in the Cameron collection. I have a copy of Dyson’s Selected Works, and as you report the paper is not there. Couldn’t find it anywhere else, either. Cameron’s collection was mostly published in ephemeral paperback (I think there were a small number of hardbacks for libraries, but the U of Chicago’s copy is in paper covers).
So I wrote Dyson, with whom I had developed a very friendly relationship (there is a second edition of AQM, and it was more work than the first, due to the ~200 Feynman diagrams in the supplement), and asked if he would consent to my retyping (and redrawing the illustration for) his article for the arXiv. He was pleased by this. I very much regret that I couldn’t get it done before he died. The reason for that was copyright problems.
I’m going to give you only bullet points for that. Cameron died in 2005. His Interstellar Communication was published by W. A. Benjamin, then purchased by Cummings, Cummings was purchased by Addison-Wesley, and most of A-W’s assets purchased by Pearson; some by Taylor & Francis (UK). Took about four years to unravel. Neither Pearson (totally unhelpful) nor T&F (much better) had any record of the Cameron collection. As this may be helpful to you down the road, here was the resolution:
A work which was in copyright prior to January 1, 1964 had to have its copyright renewed in the 28th year after original copyright or lose its US copyright protection forever. Cameron’s collection was copyrighted in 1963. It took hours, but by scouring the online catalog at the US Copyright Office (you can do it in person near the Library of Congress) I was able to convince myself that the copyright had never been renewed. As far as US copyright goes, “Gravitational Engines” is in the public domain, and so I was clear of corporate entanglements (more to the point, so is the arXiv).
However, as I learned from Dyson’s Selected Papers, the article had originally been entered into an annual contest by the Gravity Research Foundation. The contributors to this contest read historically like a Who’s Who of astrophysics, general relativists and astronomers. So I got in touch with that organization’s director, George Rideout Jr. Rideout’s father had been appointed director by Roger W. Babson. who made a pile of money and set the foundation up. The story behind this is very sad: His beloved older sister drowned, and he blamed gravity. So he thought, well, if people could only invent anti-gravity, that might prevent future disasters. So he set up the foundation. (I think they also provided some funding for GR1 [Conference on the Role of Gravitation in Physics], the first international general relativity conference, Chapel Hill, 1957.)
I quickly obtained permission from George Rideout, satisfied the arXiv officials that they were free and clear to post “Gravitational Engines,” and here we are. (As I mentioned in the arXiv posting, the abstract comes from the original Gravity Research Foundation submission; it is absent in the Cameron collection.)
Incidentally, in chasing down other things, I found something I’d been seeking for a long time, the report from the Chapel Hill conference:
https://edition-open-sources.org/publications/#sources
https://edition-open-sources.org/sources/5/index.html
(So as you can see, there are several of us oddball manuscript hunters out there.)
Theoretical physics was not that large a community in 1965, and the British community even smaller. The physicists of Dyson’s generation typically went to Cambridge (which remains the main training ground for math and physics in the UK), with smaller spillover at Oxford, Imperial College London, and Edinburgh.
Kemmer hired Higgs at Edinburgh (Peter had been in the same department as Maurice Wilkins and Rosalind Franklin at King’s College, London. He was an expert at the time on crystal structure via group theory. He did not have any direct involvement with the DNA work, though subsequently he wrote an article that had a lot to do post facto with explaining the helical structure. The big boss at the lab (not Wilkins) was apparently quite annoyed with Higgs that he didn’t want to work on DNA.) Higgs wrote a Kemmer obit for the University of Edinburgh bulletin. He had been at Edinburgh for a couple of years in the 1950s in a junior position before he returned for good in 1960 (I think).
If I recall correctly, as Peter tells the story, Sheldon Glashow (who Higgs had known since a Scottish Summer School (conference) in Physics, 1960, I think) told Higgs that if he were ever planning to be in the Northeast, Glashow would arrange for Peter to give a talk at Harvard on whatever he liked. Independently of Glashow, Dyson wrote Peter to give a talk on what is now famously the Higgs mechanism at IAS, and Peter called Glashow to say something like, “Well, I’m driving from Chapel Hill to Princeton, and I see that Cambridge is only another few hours, so…” and that led to Higgs giving pretty much the same talk at Harvard, a really important event. But if Dyson hadn’t asked Peter to come to Princeton, he would not have gone to Harvard.
[Thus the contingencies of history, always telling a fascinating tale, in this case of a concept that rocked the world of physics, and wouldn’t you know Freeman Dyson would be in the middle of it.- PG]
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