by eldavojohnWhy did you take a fellowship at Cornell and stay in the United States? There's plenty of world renowned institutions in the United Kingdom and you were a pilot in the RAF -- what appealed to you about the United States? Do you have any comments or opinions on H1-Bs and the United States' current stance on immigration?During world war II I made plans to go to Russia after the war. I had fallen in love with the Russian language, and I knew that physics and mathematics in Russia were first-rate. So I planned to stay several years in Russia to study the Russian culture as well as science. Then soon after the war Stalin made it clear that he did not welcome foreign students. So my second choice was the USA. The main reason was that money was available from the Commonwealth Fund (now the Harkness Fund) for student fellowships in the USA. It was then easier to cross the Atlantic than to cross the Channel. I applied for a Commonwealth Fellowship and got generous support for two years in the USA. I went to Cornell because I happened by chance to meet G.I.Taylor who had been at Los Alamos with the British team during the war. He said, ``Go to Cornell, that is where all the bright people from Los Alamos went after the war.'' He was right. At Cornell I worked with Bethe and Feynman who were at the cutting edge of physics at that time.I was never a pilot in the RAF, only a humble statistician collecting data about operations. The US is always schizophrenic about immigration. In those days the situation was generally worse than today, with strict immigration quotas. I benefited because I was British and we had the biggest quota. Now the situation is still bad but not so unfair as it was then. The quotas were overtly racist and designed to keep America for the WASPs (White Anglo-Saxon Protestants).by floggerHow has your education helped or hindered you? You are the "ideal" educated man. In our (American) culture, we don;t seem to be producing people devoted to learning, discovering, thinking, inventing, etc. What in your opinion can an educational system do to foster what you've become?I was extremely lucky because I came through the British education system during the war when everything was screwed up. The whole system depended on written examinations and we did not have enough ships to import paper. So there was no paper and no exams. Also there was a high shortage of teachers since all the young people were away fighting the war. As a result, I was in class only seven hours a week. A wonderful time to get an education. We had maximum freedom, and the kids learned more from one another than we would have learned from teachers.The kids today spend far too much time in class and as a result are turned off from the things they are supposed to be learning. That is true not only in the USA but also in other countries.by doomIn your article The Question of Global Warming , you make the point that the Earth's vegetation acts as a big carbon sink, and suggest that genetically engineered plants might do an even better job -- thus becoming the first person in history to make environmentalists angry by suggesting that top soil management is important. I have a few questions about this: (1) you mention the fanciful-sounding notion of "carbon-eating trees", but aren't there technologies that already exist that might do the job? There are claims that "no till" agriculture via the dreaded "roundup ready" plants reduce greenhouse gas emissions substantially. (2) A big part of the argument against immediate reductions in CO2 emissions is economic. Do the analyses you've seen really make an effort to capture all the costs and benefits associated with a move like banning coal burning completely? The annual deaths estimated from coal pollution seem big enough to make it worth doing even before you put global warming on the table.This is a complicated subject and I only discuss it in general terms. What you say about carbon-eating trees is true. Trees eat carbon almost as fast as we can burn it. No-till farming also eats carbon. The question I raised is whether we could eat more carbon by genetically engineering trees.I did not answer the question. We cannot answer it until the science of tree genetics is much better understood. The same thing is true of the effects of carbon on climate. We cannot predict the effects of carbon on climate until we understand the science of climate much better than we do now.The shale-gas revolution has changed the economics of energy production drastically. Shale-gas is a greenhouse gas, but it is otherwise clean, doing far less damage than coal to the environment and to human health. Shale-gas is cheap and well distributed over the planet. The replacement of coal by shale-gas is by far the most practical way to get rid of coal and clean up the planet.by smaddoxI am of the opinion that without economical fusion, humanity will not last more than a few thousand years. I am also of the opinion that most fusion research funding is targeted at projects with little or no application to economical fusion (I see no evidence that tokamaks or inertial confinement will ever be economical. In fact, all evidence seems to suggest they will never be economical). What are your views on the current state of fusion research? Is funding misplaced? Disproportionately allocated?I am not an expert on plasma physics. I know only that plasma physics is very difficult and poorly understood. In my opinion the governments of the world, not only the USA, made a wrong choice about forty years ago when they stopped exploring the science of fusion with small-scale experiments and put their money into high engineering projects. The big engineering projects such as ITER are absurdly expensive and can never lead to economic fusion power. I agree with your opinions about this. I consider the funding to be misplaced. The only hope of economically useful fusion power is a radically different design which might emerge from better understanding of the basic science of plasma physics.I do not agree that humanity needs economical fusion power in order to survive, unless you include the sun as a fusion power source. The sun is a splendid fusion reactor that will continue running for several billion years. All we need is to learn how to use sunlight economically. There are probably many ways to achieve this.by rotenberryProfessor Dyson,I had the pleasure of listening to you speak at Caltech in the 1980s about the Nuclear Freeze Movement. You were a supporter even though you indicated that since the number of nuclear weapons was decreasing (at that time), keeping the current number of nuclear weapons was not desirable. Thirty years have passed. Do you think this movement accomplished any of their goals?The biggest reduction of nuclear weapons was done by George Bush Senior in 1989. He removed all tactical nukes from the US army and the surface navy. This was done quietly and unilaterally without any international negotiations. He got rid of about half of all our nuclear weapons, and these were the most dangerous weapons, deployed all over the world and likely to be involved in local fighting. As a result of his action, the world is much safer.I believe we could go much further in the same direction. Unilateral action is much quicker and more effective than negotiating treaties. The next obvious step would be to get rid of nuclear bombs on airplanes. After that, land-based nuclear missiles, leaving the nuclear missile submarines till last. I think there is a good chance that the military will support such unilateral moves. The military knows that our nuclear weapons are essentially useless for fighting real wars. The problem is to educate the politicians.by manonthemoonGiven that we finally seem to have a vital and growing private space industry, what do you think the likeliest successful target for long term space industrialization/exploitation/habitation is? The Moon, near earth asteroids, Mars?I think it is absurd and illusory to guess what kind of space activities will be profitable. I think of the Virginia colonists who came to America to mine gold and finally got rich by growing tobacco. This is a situation where the market will decide and the market is unpredictable. They began with about a hundred years of fishing and trading operations off the coast before settlements became profitable. Things may go faster than this in space, or things may go slower. I see no point in guessing.by SixDimensionalArrayIn my understanding, the concepts of nuclear pulse propulsion that were investigated in the Orion Project had the highest real potential for generating enormous energies required for "faster" travel in space than anything we have, even today. I have always felt that it is a tragedy that this research couldn't be taken further into our modern realities of exploration.Today, we have NASA exploring the potential (on a very small scale) of faster than light (FTL) travel using ideas such as the Alcubierre drive . In common discussion, we now hear about things such as: dark matter, quantum teleportation, FTL particles in the form of cosmic rays, the likely discovery of the Higgs Boson, spacetime, etc. These appear, to the layman like myself, to be serious discussions, with new realities and new possibilities being discovered every day.The entirety of the NASA space program as we know it has developed within the last 60 years.Given the advances in technology we have made in such a short time, the laws of physics, and the realities of the politics of our world, do you think it is feasible that we will develop the ability for very fast, near or faster-than-light travel in the next 60 years, and which direction seems the most feasible to you?Thank you for your contributions to science, I am humbled to be able to ask this question of you!I disagree with almost everything here. There are two NASAs, the real NASA which is intensely conservative and likes to use safe and reliable technology, and the paper NASA which pretends to support radical ideas but never does anything real. The paper NASA will generate a lot of hype but will certainly not lead to anything real. Faster-than-light travel is rubbish. The Orion project was designed to travel only within the solar system and is far too slow for interesting interstellar voyages. In the next 60 years we may see a public highway system started which will bring down the costs of space operations substantially, but it will not be increasing the speed of travel substantially. The important barrier to space operations is cost, not speed.by gestalt_n_pepperWhile space travel is important for human survival in the long term, the more I think about it, the more it seems that developing a human style, scalable, artificial intelligence has for more potential to provide humans with rapid access to a much larger set of useful answers in the general domain of practical, solvable problems.The investment should be, relatively speaking, trivial, and we already have 7 billion or so working models, so I think it's fairly certain that this can be done. Given a choice, would you advocate more resources be allocated to space travel, or AI?You ask whether, given a choice, I would put more resources into space or AI. My answer is that either choice would be stupid. Politicians always want to make such choices too soon, because they imagine they can pick winners. Usually they pick losers. The only way to improve the chances for finding winners is to keep all the choices open and try them all. That is particularly true for space and AI, which are not really competing with each other. They are done by different kinds of people in different kinds of enterprise. Both can and should be supported. It would be totally stupid to starve one and over-feed the other.My own opinion is that AI has failed to fulfill its promise because we are using the wrong kind of computers. We are using digital computers, and the human brain is probably analog rather than digital. So my guess is that AI will succeed only after we move from digital to analog computing. This is a tough intellectual problem that cannot be solved just by spending a lot of money.by BorisSkratchunkovPerhaps this has been asked already (throughout the various interviews, engagements, etc that you have had hitherto), but what are your general thoughts on the Singularity movement, transhumanism, and Ray Kurzweil's overall philosophy on human progress? Are these folks realistic, optimistic, or pessimistic? What are your beliefs about the current state of human advancement, and what we must work on as we careen toward the future?I do not believe in any kind of ism. I believe we understand very little about human nature, about psychology or about economics. I do not take seriously any of the people who claim to predict the future. I believe them even less when they claim to be accurate predictors.by werepantsThe early to mid 20th century was one of the most dynamic times to ever happen in physics, with massive shifts in thinking and incredible applications of science that led to some of the greatest achievements of mankind. For a variety of reasons, it seems as though progress recently has been more incremental, collective, and focused on confirming the big ideas of previous thinkers. What attribute do you think is most needed in the upcoming generation of physicists to usher in the next era of scientific progress?Scientific progress happens in two ways, either driven by new ideas or by new tools. The first half of the twentieth century was the time of new ideas, the second half was the time of new tools.New ideas are more exciting but new tools are often more important. For the twenty-first century, it seems that the most important contribution of physicists is to build new tools for other sciences. Examples, chemistry and biology and astronomy and computer-technology, all driven by new tools supplied by physics. This is not so exciting as discovering the Dirac equation, but probably more useful. There is plenty of good stuff for physicists to do.by eldavojohnWhen weighted against population, it appears that there are fewer "Renaissance men/women" than there have been historically. I've heard many regular people opine about how fields require more depth and learning to make progress in them but, as a polymath yourself, what is your opinion on it?It is undoubtedly true that we are today drowning in information. Each of us knows a smaller fraction of the total information than earlier generations knew. Our skills have become more specialized. But I do not see any decrease in breadth of interest. The young people today are still interested in as wide a variety of subjects as we old ones were. Tools of knowledge such as the internet and Wikipedia make it easier for young people today to spread their minds over many subjects.by ideonexusYou're daughter Esther is one of the most incredibly inspiring women role models alive today . Do you have any parenting advice for those of out here with kids of our own who would like them to become similarly active, positive, and brilliant adults?Thank you for your compliment to Esther and to her parents. We do not claim credit for her achievements. She was lucky to be the oldest of six, so we had little time for her and gave her little of our attention. She befitted from our benign neglect. She learned from a young age to choose her own path through life. She chose for her motto: "Always make new mistakes." I believe that is the key to her happy and productive life.