Richard Phillips Feynman (May 11, 1918 – February 15, 1988) was an American physicist known for the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of the superfluidity of supercooled liquid helium, as well as work in particle physics (the parton model was proposed by him). For his contributions to the development of quantum electrodynamics, Feynman was a joint recipient of the Nobel Prize in Physics in 1965, together with Julian Schwinger and Sin-Itiro Tomonaga. Feynman developed a widely-used pictorial representation scheme for the mathematical expressions governing the behavior of subatomic particles, which later became known as Feynman diagrams. During his lifetime and after his death, Feynman became one of the most publicly known scientists in the world.
He assisted in the development of the atomic bomb and was a member of the panel that investigated the Space Shuttle Challenger disaster. In addition to his work in theoretical physics, Feynman has been credited with pioneering the field of quantum computing, and introducing the concept of nanotechnology (creation of devices at the molecular scale). He held the Richard Chace Tolman professorship in theoretical physics at Caltech.
Feynman was a keen popularizer of physics in both his books and lectures, notably a 1959 talk on top-down nanotechnology called There's Plenty of Room at the Bottom, and The Feynman Lectures on Physics. Feynman is also known for his semi-autobiographical books Surely You're Joking, Mr. Feynman! and What Do You Care What Other People Think?, and through books about him, such as Tuva or Bust! He was also known as a prankster, juggler, a proud amateur painter, and a bongo player. Richard Feynman was regarded as an eccentric and a free spirit. He liked to pursue multiple seemingly independent paths, such as biology, art, percussion, Maya hieroglyphs, and lock picking.
Richard Feynman's interest in biology was more than casual. He was a friend of Esther Lederberg, the geneticist and microbiologist who developed replica plating and discovered bacteriophage lambda (though often others received credit for her work). It is not surprising that both these engaging people should be friends, as they also shared other scientists as friends. These included physicists in nuclear research who for moral reasons switched to genetics (such as Leó Szilárd, Guido Pontecorvo, Aaron Novick, and Carl Sagan).
At Princeton, the physicist Robert R. Wilson encouraged Feynman to participate in the Manhattan Project—the wartime U.S. Army project at Los Alamos developing the atomic bomb. Feynman said he was persuaded to join this effort to build it before Nazi Germany. He was assigned to Hans Bethe's theoretical division, and impressed Bethe enough to be made a group leader. Together with Bethe, he developed the Bethe-Feynman formula for calculating the yield of a fission bomb, which built upon previous work by Robert Serber. He immersed himself in work on the project, and was present at the Trinity bomb test. Feynman claimed to be the only person to see the explosion without the very dark glasses provided, reasoning that it was safe to look through a truck windshield, as it would screen out the harmful ultraviolet radiation.
As a junior physicist, he was not central to the project. The greater part of his work was administering the computation group of human computers in the Theoretical division (one of his students there, John G. Kemeny, would later go on to co-write the computer language BASIC). Later, with Nicholas Metropolis, he assisted in establishing the system for using IBM punch cards for computation. Feynman succeeded in solving one of the equations for the project that were posted on the blackboards. However, they did not "do the physics right" and Feynman's solution was not used in the project.
Feynman's other work at Los Alamos included calculating neutron equations for the Los Alamos "Water Boiler", a small nuclear reactor, to measure how close an assembly of fissile material was to criticality. On completing this work he was transferred to the Oak Ridge facility, where he aided engineers in calculating safety procedures for material storage, so that inadvertent criticality accidents (for example, storing subcritical amounts of fissile material in proximity on opposite sides of a wall) could be avoided. He also did theoretical work and calculations on the proposed uranium-hydride bomb, which later proved to be infeasible.
Feynman was sought out by physicist Niels Bohr for one-on-one discussions. He later discovered the reason: most physicists were too in awe of Bohr to argue with him. Feynman had no such inhibitions, vigorously pointing out anything he considered to be flawed in Bohr's thinking. Feynman said he felt as much respect for Bohr as anyone else, but once anyone got him talking about physics, he would become so focused he forgot about social niceties.
Due to the top secret nature of the work, Los Alamos was isolated. In his own words, "There wasn't anything to do there". Bored, Feynman indulged his curiosity by learning to pick the combination locks on cabinets and desks used to secure papers. Feynman played many jokes on colleagues. In one case he found the combination to a locked filing cabinet by trying the numbers a physicist would use (it proved to be 27-18-28 after the base of natural logarithms, e = 2.71828...), and found that the three filing cabinets where a colleague kept a set of atomic bomb research notes all had the same combination. He left a series of notes as a prank, which initially spooked his colleague, Frederic de Hoffman, into thinking a spy or saboteur had gained access to atomic bomb secrets. On several occasions Feynman drove to Albuquerque to see his ailing wife in a car borrowed from Klaus Fuchs, who was later discovered to be transporting nuclear secrets in his car to Albuquerque for the Soviets.
On occasion, Feynman would find an isolated section of the mesa to drum in the style of American natives; "and maybe I would dance and chant, a little". These antics did not go unnoticed, and rumors spread about a mysterious Indian drummer called "Injun Joe". He also became a friend of laboratory head J. Robert Oppenheimer, who unsuccessfully tried to court him away from his other commitments to work at the University of California, Berkeley, after the war.
Feynman alludes to his thoughts on the justification for getting involved in the Manhattan project in The Pleasure of Finding Things Out. As mentioned earlier, he felt the possibility of Nazi Germany developing the bomb before the Allies was a compelling reason to help with its development for the U.S. However, he goes on to say that it was an error on his part not to reconsider the situation when Germany was defeated. In the same publication Feynman also talks about his worries in the atomic bomb age, feeling for some considerable time that there was a high risk that the bomb would be used again soon so that it was pointless to build for the future. Later he describes this period as a 'depression.'
Although his professorship at Princeton would have included teaching duties along with a position at the Institute for Advanced Study, Feynman opted for Caltech. Feynman noted in his book, "Surely You're Joking Mr. Feynman!" that his decision was influenced by a desire to live in a mild climate, a goal he chose while having to put tire chains on his car in the middle of a snowstorm in Ithaca, New York.
Feynman has been called the "Great Explainer". He gained a reputation for taking great care when giving explanations to his students and for assigning himself a moral duty to make the topic accessible. His guiding principle was that if a topic could not be explained in a freshman lecture it was not yet fully understood. Feynman gained great pleasure from coming up with such a "freshman-level" explanation, for example, of the connection between spin and statistics. What he said was that groups of particles with spin 1/2 "repel", whereas groups with integer spin "clump". This was a brilliantly simplified way of demonstrating how Fermi-Dirac statistics and Bose-Einstein statistics evolved as a consequence of studying how fermions and bosons behave under a rotation of 360°. This was also a question he pondered in his more advanced lectures and to which he demonstrated the solution in the 1986 Dirac memorial lecture. In the same lecture he further explained that antiparticles must exist since if particles only had positive energies they would not be restricted to a so-called "light cone". He opposed rote learning or unthinking memorization and other teaching methods that emphasized form over function. He put these opinions into action whenever he could, from a conference on education in Brazil to a State Commission on school textbook selection. Clear thinking and clear presentation were fundamental prerequisites for his attention. It could be perilous even to approach him when unprepared, and he did not forget the fools or pretenders.
During one sabbatical year, he returned to Newton's Principia Mathematica to study it anew; what he learned from Newton, he passed along to his students, such as Newton's attempted explanation of diffraction.
Feynman did significant work while at Caltech, including research in:
He also developed Feynman diagrams, a bookkeeping device which helps in conceptualizing and calculating interactions between particles in spacetime, notably the interactions between electrons and their antimatter counterparts, positrons. This device allowed him, and later others, to approach time reversibility and other fundamental processes. Feynman famously painted Feynman diagrams on the exterior of his van.
Feynman diagrams are now fundamental for string theory and M-theory, and have even been extended topologically. Feynman's mental picture for these diagrams started with the hard sphere approximation, and the interactions could be thought of as collisions at first. It was not until decades later that physicists thought of analyzing the nodes of the Feynman diagrams more closely. The world-lines of the diagrams have developed to become tubes to allow better modelling of more complicated objects such as strings and membranes.
From his diagrams of a small number of particles interacting in spacetime, Feynman could then model all of physics in terms of those particles' spins and the range of coupling of the fundamental forces. Feynman attempted an explanation of the strong interactions governing nucleons scattering called the parton model. The parton model emerged as a complement to the quark model developed by his Caltech colleague Murray Gell-Mann. The relationship between the two models was murky; Gell-Mann referred to Feynman's partons derisively as "put-ons". Feynman did not dispute the quark model; for example, when the fifth quark was discovered, Feynman immediately pointed out to his students that the discovery implied the existence of a sixth quark, which was duly discovered in the decade after his death.
After the success of quantum electrodynamics, Feynman turned to quantum gravity. By analogy with the photon, which has spin 1, he investigated the consequences of a free massless spin 2 field, and was able to derive the Einstein field equation of general relativity, but little more.
At this time, in the early 1960s Feynman exhausted himself by working on multiple major projects at the same time, including his Feynman Lectures on Physics: while at Caltech, Feynman was asked to "spruce up" the teaching of undergraduates. After three years devoted to the task, he produced a series of lectures that would eventually become the Feynman Lectures on Physics, one reason that Feynman is still regarded as one of the greatest teachers of physics. He wanted a picture of a drumhead sprinkled with powder to show the modes of vibration at the beginning of the book. Outraged by many rock and roll and drug connections that one could make from the image, the publishers changed the cover to plain red, though they included a picture of him playing drums in the foreword. Feynman later won the Oersted Medal for teaching, of which he seemed especially proud. His students competed keenly for his attention; he was once awakened when a student solved a problem and dropped it in his mailbox; glimpsing the student sneaking across his lawn, he could not go back to sleep, and he read the student's solution. The next morning his breakfast was interrupted by another triumphant student, but Feynman informed him that he was too late.
Partly as a way to bring publicity to progress in physics, Feynman offered $1000 prizes for two of his challenges in nanotechnology, claimed by William McLellan and Tom Newman, respectively. He was also one of the first scientists to conceive the possibility of quantum computers. Many of his lectures and other miscellaneous talks were turned into books, including The Character of Physical Law and QED: The Strange Theory of Light and Matter. He gave lectures which his students annotated into books, such as Statistical Mechanics and Lectures on Gravity. The Feynman Lectures on Physics occupied two physicists, Robert B. Leighton and Matthew Sands as part-time co-authors for several years. Even though they were not adopted by most universities as textbooks, the books continue to be bestsellers because they provide a deep understanding of physics. As of 2005, The Feynman Lectures on Physics has sold over 1.5 million copies in English, an estimated 1 million copies in Russian, and an estimated half million copies in other languages.
In 1974 Feynman delivered the Caltech commencement address on the topic of cargo cult science, which has the semblance of science but is only pseudoscience due to a lack of "a kind of scientific integrity, a principle of scientific thought that corresponds to a kind of utter honesty" on the part of the scientist. He instructed the graduating class that "The first principle is that you must not fool yourself—and you are the easiest person to fool. So you have to be very careful about that. After you've not fooled yourself, it's easy not to fool other scientists. You just have to be honest in a conventional way after that.
In the late 1980s, according to "Richard Feynman and the Connection Machine", Feynman played a crucial role in developing the first massively parallel computer, and in finding innovative uses for it in numerical computations, in building neural networks, as well as physical simulations using cellular automata (such as turbulent fluid flow), working with Stephen Wolfram at Caltech. His son, Carl, also played a role in the development of the original Connection Machine engineering; Feynman influencing the interconnects while his son worked on the software.
Shortly before his death, Feynman criticized string theory in an interview: "I don't like that they're not calculating anything," he said. "I don't like that they don't check their ideas. I don't like that for anything that disagrees with an experiment, they cook up an explanation—a fix-up to say, 'Well, it still might be true.'" These words have since been much-quoted by opponents of the string-theoretic direction for particle physics.
He was married a second time in June 1952, to Mary Louise Bell of Neodesha, Kansas; this marriage was brief and unsuccessful. He later married Gweneth Howarth from Ripponden, Yorkshire,United Kingdom, who shared his enthusiasm for life and spirited adventure. Besides their home in Altadena, California, they had a beach house in Baja California, the latter of which was purchased with the prize money from Feynman's Nobel Prize, at that time $55,000 (of which Feynman was entitled to a third). They remained married until Feynman's death. They had a son, Carl, in 1962, and adopted a daughter, Michelle, in 1968.
Feynman had a great deal of success teaching Carl using discussions about ants and Martians as a device for gaining perspective on problems and issues; he was surprised to learn that the same teaching devices were not useful with Michelle. Mathematics was a common interest for father and son; they both entered the computer field as consultants and were involved in advancing a new method of using multiple computers to solve complex problems—later known as parallel computing. The Jet Propulsion Laboratory retained Feynman as a computational consultant during critical missions. One coworker characterized Feynman as akin to Don Quixote at his desk, rather than at a computer workstation, ready to do battle with the windmills.
According to his colleague, Professor Steven Frautschi, Feynman was the only person in the Altadena region to buy flood insurance after the massive 1978 fire, predicting correctly that the fire's destruction would lead to land erosion, causing mudslides and flooding. The flood occurred in 1979 after winter rains and destroyed multiple houses in the neighborhood. Feynman's use of insurance, an inherently future-looking device, was not only fortunate but ironic in light of his depiction of his outlook following the Manhattan Project. Feynman wrote that in the years following the development and use of the atomic bomb, whenever seeing the construction of a bridge or a new building, he was unavoidably struck by the thought that the labor was futile and in vain, as the human race would soon be undone by the bomb.
Feynman traveled a great deal, notably to Brazil, and near the end of his life schemed to visit the Russian land of Tuva, a dream that, due to Cold War bureaucratic problems, never became reality. The day after he died, a letter arrived for him from the Soviet government giving him authorization to travel to Tuva. During this period he discovered that he had a form of cancer, but, thanks to surgery, he managed to hold it off. Out of his enthusiastic interest in reaching Tuva came the phrase "Tuva or Bust" (also the title of a book about his efforts to get there), which was tossed about frequently amongst his circle of friends in hope that they, one day, could see it firsthand. The documentary movie Genghis Blues mentions some of his attempts to communicate with Tuva and chronicles the journey when some of his friends did make it there. His attempts to circumvent the complex Soviet bureaucratic system which kept Tuva sealed, and also his attempts to write and send a letter using an English-Russian and Russian-Tuvan dictionary, as well as his earlier efforts to translate Mayan hieroglyphics, all demonstrate his life-long addiction to solving puzzles, locks, and cyphers. At the time, they also earned him a reputation of eccentricity.
Feynman did not work only on physics, and had a large circle of friends from all walks of life, including the arts. He took up drawing at one time and enjoyed some success under the pseudonym "Ofey", culminating in an exhibition dedicated to his work. He learned to play drums (frigideira) in a samba style in Brazil by dint of persistence and practice, and participated in a samba school. Apparently Feynman did not much appreciate orchestral music, but he had a keen sense of rhythm and timing which extended to a personal timekeeping center in his brain which let him operate without ever needing a watch. In 1979 he participated as a session musician in Led Zeppelin's "Fool in the Rain". In addition, he had some degree of synesthesia for equations, explaining that the letters in certain mathematic functions appeared in color for him, even though invariably printed in standard black-and-white.
According to Genius, the James Gleick biography, Feynman experimented with LSD during his professorship at Caltech. Somewhat embarrassed by his actions, Feynman sidestepped the issue when dictating his anecdotes; consequently, the "Altered States" chapter in Surely You're Joking, Mr. Feynman! describes only marijuana and ketamine experiences at John Lilly's famed sensory deprivation tanks, as a way of studying consciousness. Feynman gave up alcohol when he began to show early signs of alcoholism, as he did not want to do anything that could damage his brain.
Feynman also had very liberal views on sexuality and was not ashamed of admitting it. In Surely You're Joking, Mr. Feynman!, he gives advice on the best way to pick up a girl in a hostess bar. At Caltech, he used a nude/topless bar as an office away from his usual office, making sketches or writing physics equations on paper placemats. When the county officials tried to close the locale, all visitors except Feynman refused to testify in favor of the bar, fearing that their families or patrons would learn about their visits. Only Feynman accepted, and in court, he affirmed that the bar was a public need, stating that craftsmen, technicians, engineers, common workers "and a physics professor" frequented the establishment. While the bar lost the court case, it was allowed to remain open as a similar case was pending appeal.
He was unfortunate in developing two rare forms of cancer, namely Liposarcoma and Waldenström macroglobulinemia, dying shortly after a final attempt at surgery for the former. His last recorded words are noted as "I'd hate to die twice. It's so boring."
Feynman was requested to serve on the Presidential Rogers Commission which investigated the Challenger disaster of 1986. Feynman devoted the latter half of his book What Do You Care What Other People Think? to his experience on the Rogers Commission, straying from his usual convention of brief, light-hearted anecdotes to deliver an extended and sober narrative. Feynman's account reveals a disconnect between NASA's engineers and executives that was far more striking than he expected. His interviews of NASA's high-ranking managers revealed startling misunderstandings of elementary concepts.
In one example, early tests resulted in some of the booster rocket's o-rings burning a third of the way through. These o-rings provided the gas-tight seal needed between the vertically stacked cylindrical sections that made up the solid fuel booster. NASA managers recorded this result as demonstrating that the o-rings had a "safety factor" of 3. Feynman incredulously explains the magnitude of this error: a "safety factor" refers to the practice of building an object to be capable of withstanding more force than it will ever conceivably be subjected to. To paraphrase Feynman's example, if engineers built a bridge that could bear 3,000 pounds without any damage, even though it was never expected to bear more than 1,000 pounds in practice, the safety factor would be 3. If, however, a 1,000 pound truck drove across the bridge and it cracked at all, the safety factor is now zero: the bridge is defective.
Feynman was clearly disturbed by the fact that NASA management not only misunderstood this concept, but in fact inverted it by using a term denoting an extra level of safety to describe a part that was actually defective and unsafe. Feynman continued to investigate the lack of communication between NASA's management and its engineers and was struck by the management's claim that the risk of catastrophic malfunction on the shuttle was 1 in 105; i.e., 1 in 100,000. Feynman immediately realized that this claim was risible on its face; as he described, this assessment of risk would entail that NASA could expect to launch a shuttle every day for the next 274 years without an accident. Investigating the claim further, Feynman discovered that the 1 in 105 figure was stating what they claimed that the failure rate ought to be, given that it was a manned vehicle, and working backwards to generate the failure rate of components.
Feynman was disturbed by two aspects of this practice. First, NASA management assigned a probability of failure to each individual bolt, sometimes claiming a probability of 1 in 108; that is, one in one hundred million. Feynman pointed out that it is impossible to calculate such a remote possibility with any scientific rigor. Secondly, Feynman was bothered not just by this sloppy science but by the fact that NASA claimed that the risk of catastrophic failure was "necessarily" 1 in 105. As the figure itself was beyond belief, Feynman questioned exactly what "necessarily" meant in this context—did it mean that the figure followed logically from other calculations, or did it reflect NASA management's desire to make the numbers fit?
Feynman suspected that the 1/100,000 figure was wildly fantastical, and made a rough estimate that the true likelihood of shuttle disaster was closer to 1 in 100. He then decided to poll the engineers themselves, asking them to write down an anonymous estimate of the odds of shuttle explosion. Feynman found that the bulk of the engineers' estimates fell between 1 in 50 and 1 in 100. Not only did this confirm that NASA management had clearly failed to communicate with their own engineers, but the disparity engaged Feynman's emotions. When describing these wildly differing estimates, Feynman briefly lapses from his damaging but dispassionate detailing of NASA's flaws to recognize the moral failing that resulted from a scientific failing: he was clearly upset that NASA presented its clearly fantastical figures as fact to convince a member of the public, schoolteacher Christa McAuliffe, to join the crew. Feynman was not uncomfortable with the concept of a 1/100 risk factor, but felt strongly that the recruitment of laypeople required an honest portrayal of the real risk involved.
Feynman's investigation eventually suggested to him that the cause of the Challenger explosion was the very part to which NASA management so mistakenly assigned a safety factor. The o-rings were rubber rings designed to form a seal in the shuttle's solid rocket boosters, preventing the rockets' super-heated gas from escaping and damaging other parts of the vehicle. Feynman suspected that despite NASA's claims, the o-rings were unsuitable at low temperatures and lost their resilience when cold, thus failing to expand and maintain a tight seal when rocket pressure distorted the structure of the solid fuel booster. Feynman's suspicions were corroborated by General Kutyna, also on the commission, who cunningly provided Feynman with a broad hint by asking about the effect of cold on o-ring seals after mentioning that the temperature on the day of the launch was far lower than had been the case with previous launches: below freezing at 28 or 29 Fahrenheit (-2.2 to -1.6 °C); previously, the coldest launch had been at 53 °F (12 °C).
Feynman obtained samples of the seals used on the Challenger by dismantling a model supplied to the commission, intending to test the resilience of the seals at low temperature in front of the TV cameras, but in an act that he claims to have been ashamed of, ran the test first in private to ensure that it was indeed the case that low temperature reduced the resilience of the rubber as he suspected.
When testifying before Congress, Feynman questioned a NASA manager with seeming innocence, focusing on the cold temperatures that the o-rings could be subjected to while remaining resilient (i.e., effective). The NASA manager insisted that o-rings would retain their resilience even in extreme cold. But Feynman managed to obtain a glass of iced water, and used it to cool a section of o-ring seal clamped flat with a small clamp he had purchased earlier at a hardware store.
After receiving repeated assurances that the o-rings would remain resilient at subzero temperatures, and at an opportune moment selected by Kutyna during a particular NASA slide-show, Feynman took the o-ring out of the water and removed the vise, revealing that the o-ring remained flattened, demonstrating a lack of resilience at 32 °F (0 °C), which was warmer than the launch temperature. While Feynman worried that the audience did not realize the importance of his action, The New York Times picked the story up, crediting Feynman for his ruse, and earning him a small measure of fame.
Feynman's investigations also revealed that there had been many serious doubts raised about the o-ring seals by engineers at Morton Thiokol, which made the solid fuel boosters, but communication failures had led to their concerns being ignored by NASA management. He found similar failures in procedure in many other areas at NASA, but singled out its software development for praise due to its rigorous and highly effective quality control procedures which were under threat from NASA management which wished to reduce testing to save money since the tests were always passed.
Based on his experiences with NASA's management and engineers, Feynman concluded that the serious deficiencies in NASA management's scientific understanding, the lack of communication between the two camps, and the gross misrepresentation of the shuttle's dangers, required that NASA take a hiatus from shuttle launches until it could resolve its internal inconsistencies and present an honest picture of the shuttle's reliability. Feynman soon found that, while he respected the intellects of his fellow Commission members, they universally finished their criticisms of NASA with clear affirmations that the Challenger disaster should be addressed by NASA internally, but that there was no need for NASA to suspend its operations or to receive less funding. Feynman felt that the Commission's conclusions were not compatible with its findings, and could not in good conscience recommend that such a deeply flawed organization should continue without a suspension of operations and a major overhaul. His fellow commission members were alarmed by Feynman's dissension, and it was only after much petitioning that Feynman's minority report was included at all: as an appendix to the official document.
Feynman's book What Do You Care What Other People Think? included a copyedited version of the appendix in addition to his narrative account.
M8 Entertainment Inc. announced in May 2006 that a movie would be made about the disaster. Challenger (2008) is to be directed by Philip Kaufman—whose 1983 film The Right Stuff chronicled the early history of the space program—and would focus on the role of Feynman in the ensuing investigation. David Strathairn will play Feynman.
On May 4, 2005 the United States Postal Service issued the American Scientists commemorative set of four 37-cent self-adhesive stamps in several configurations. The scientists depicted were Richard Feynman, John von Neumann, Barbara McClintock, and Josiah Willard Gibbs. Feynman's stamp, sepia-toned, features a photograph of a 30-something Feynman and eight small Feynman diagrams.
The main building for the Computing Division at Fermilab, the FCC, is named in his honor: The "Feynman Computing Center".