The nuclear force (or nucleon-nucleon interaction or residual strong force) is the force between two or more nucleons. It is responsible for binding of protons and neutrons into atomic nuclei. The energy released causes the masses of nuclei to be less than the total mass of the protons and neutrons which form them.

The nuclear force is now understood as a residual effect of the even more powerful strong force, or strong interaction, which is the attractive force that binds particles called quarks together, to form the nucleons themselves. This more powerful force is mediated by particles called gluons. Gluons hold quarks together with a force like that of electric charge, but of far greater power.

The concept of a nuclear force was first quantitatively constructed in 1934, shortly after the discovery of the neutron revealed that atomic nuclei were made of protons and neutrons, held together by an attractive force. The nuclear force at that time was conceived to be transmitted by particles called mesons, which were predicted in theory before being discovered in 1947. In the 1970’s, further understanding revealed these mesons to be combinations of quarks and gluons, transmitted between nucleons that themselves were made of quarks and gluons. This new model allowed the strong forces that held nucleons together, to be felt in neighboring nucleons, as residual strong forces.

The nuclear forces arising between nucleons are now seen to be analogous to the forces in chemistry between neutral atoms called van der Waals forces. Such forces between atoms are much weaker than the electrical forces that hold the atoms themselves together, and their range is shorter, because they arise from spontaneous separation of charges inside the atom. Similarly, even though nucleons are made of quarks and gluons that are in combinations which cancel most gluon forces, some combinations of quarks and gluons nevertheless leak away from nucleons, in the form of short-range nuclear force fields that extend from one nucleon to another close by. These nuclear forces are very weak compared to direct gluon forces inside nucleons, and they extend only over a few nuclear diameters, falling exponentially with distance. Nevertheless, they are strong enough to bind neutrons and protons over short distances, and overcome the electrical repulsion between protons in the nucleus.

History

The nuclear force has been at the heart of nuclear physics ever since the field was born in 1932 with the discovery of the neutron by James Chadwick. The traditional goal of nuclear physics is to understand the properties of atomic nuclei in terms of the 'bare' interaction between pairs of nucleons, or nucleon-nucleon forces (''NN'' forces).

In 1934, Hideki Yukawa made the earliest attempt to explain the nature of the nuclear force. According to his theory, massive bosons (mesons) mediate the interaction between two nucleons. Although, in light of QCD, meson theory is no longer perceived as fundamental, the meson-exchange concept (where hadrons are treated as elementary particles) continues to represent the best working model for a quantitative ''NN'' potential.

Historically, it was a formidable task to describe the nuclear force phenomenologically, and the first semi-empirical quantitative models came in the mid-1950s. There has been substantial progress in experiment and theory related to the nuclear force. Most basic questions were settled in the 1960s and 1970s. In recent years, experimenters have concentrated on the subtleties of the nuclear force, such as its charge dependence, the precise value of the π''NN'' coupling constant, improved phase shift analysis, high-precision ''NN'' data, high-precision ''NN'' potentials, ''NN'' scattering at intermediate and high energies, and attempts to derive the nuclear force from QCD.

To a large extent, the nuclear force can be understood in terms of the exchange of virtual light mesons, such as the pions. Sometimes the nuclear force is called the residual strong force, in contrast to the strong interactions which are now understood to arise from quantum chromodynamics (QCD). This phrasing arose during the 1970s when QCD was being established. Before that time, the ''strong nuclear force'' referred to the inter-nucleon potential. After the verification of the quark model, ''strong interaction'' has come to mean QCD.

Basic properties of the nuclear force

The nuclear force is only felt among hadrons. At small separations between nucleons (less than ~ 0.5 fm between their centers) the force is very powerfully repulsive, which keeps the nucleons at a certain average separation, even if they are of different types. This repulsion is to be understood in terms of the Pauli exclusion force for identical nucleons (such as two neutrons or two protons), and also a Pauli exclusion between quarks of the same type within nucleons, when the nucleons are different (a proton and a neutron, for example). As will be discussed, the nuclear force also has a "tensor" component which depends on whether or not the spins of the nucleons are aligned or anti-aligned. Beyond about 1.7 femtometer (fm) separation, the force drops to negligibly small values.

At short distances, the nuclear force is stronger than the Coulomb force; it can overcome the Coulomb repulsion of protons inside the nucleus. However, the Coulomb force between protons has a much larger range and becomes the only significant force between protons when their separation exceeds about 2.5 fm.

To disassemble a nucleus into unbound protons and neutrons would require doing work against the nuclear force. Conversely, energy is released when a nucleus is created from other nucleons or nuclei: the nuclear binding energy. Because of mass–energy equivalence (i.e. Einstein's famous formula ''E'' = ''mc''²), releasing this energy causes the mass of the nucleus to be lower than the total mass of the individual nucleons, leading to the so-called "mass deficit".

The nuclear force is nearly independent of whether the nucleons are neutrons or protons. This property is called ''charge independence''. It depends on whether the spins of the nucleons are parallel or antiparallel, and has a noncentral or ''tensor'' component. This part of the force does not conserve orbital angular momentum, which is a constant of motion under central forces.

Since nucleons have no color charge, the nuclear force does not ''directly'' involve the force carriers of quantum chromodynamics, the gluons. However, just as electrically neutral atoms (each composed of cancelling charges) attract each other via the second-order effects of electrical polarization, via the van der Waals forces (London forces), so by analogy, "color-neutral" nucleons may attract each other by a type of polarization which allows some basically gluon-mediated effects to be carried from one color-neutral nucleon to another, via the virtual mesons which transmit the forces, and which themselves are held together by virtual gluons. It is this ''van der Waals-like'' nature which is responsible for the term "residual" in the term "residual strong force." The basic idea is that while the nucleons are "color-neutral," just as atoms are "charge-neutral," in both cases, polarization effects acting between near-by neutral particles allow a "residual" charge effect to cause net charge-mediated attraction between uncharged species, although it is necessarily of a much weaker and less direct nature than the basic forces which act internally within the particles.

Nucleon-nucleon potentials

Two-nucleon systems such as the deuteron, the nucleus of a deuterium atom, as well as proton-proton or neutron-proton scattering are ideal for studying the ''NN'' force. Such systems can be described by attributing a ''potential'' (such as the Yukawa potential) to the nucleons and using the potentials in a Schrödinger equation. The form of the potential is derived phenomenologically, although for the long-range interaction, meson-exchange theories help to construct the potential. The parameters of the potential are determined by fitting to experimental data such as the deuteron binding energy or ''NN'' elastic scattering cross sections (or, equivalently in this context, so-called ''NN'' phase shifts).

The most widely used ''NN'' potentials are the Paris potential, the Argonne AV18 potential, the CD-Bonn potential and the Nijmegen potentials.

A more recent approach is to develop effective field theories for a consistent description of nucleon-nucleon and three-nucleon forces. In particular, chiral symmetry breaking can be analysed in terms of an effective field theory (called chiral perturbation theory) which allows perturbative calculations of the interactions between nucleons with pions as exchange particles.

From nucleons to nuclei

The ultimate goal of nuclear physics would be to describe all nuclear interactions from the basic interactions between nucleons. This is called the ''microscopic'' or ''ab initio'' approach of nuclear physics. There are two major obstacles to overcome before this dream can become reality:

Calculations in many-body systems are difficult and require advanced computation techniques.

There is evidence that three-nucleon forces (and possibly higher multi-particle interactions) play a significant role. This means that three-nucleon potentials must be included into the model.

This is an active area of research with ongoing advances in computational techniques leading to better first-principles calculations of the nuclear shell structure. Two- and three-nucleon potentials have been implemented for nuclear masses up to A=12.

Nuclear potentials

A successful way of describing nuclear interactions is to construct one potential for the whole nucleus instead of considering all its nucleon components. This is called the ''macroscopic'' approach. For example, scattering of neutrons from nuclei can be described by considering a plane wave in the potential of the nucleus, which comprises a real part and an imaginary part. This model is often called the optical model since it resembles the case of light scattered by an opaque glass sphere.

Nuclear potentials can be ''local'' or ''global'': local potentials are limited to a narrow energy range and/or a narrow nuclear mass range, while global potentials, which have more parameters and are usually less accurate, are functions of the energy and the nuclear mass and can therefore be used in a wider range of applications.

References

Gerald Edward Brown and A. D. Jackson, ''The Nucleon-Nucleon Interaction'', (1976) North-Holland Publishing, Amsterdam ISBN 0-7204-0335-9

R. Machleidt and I. Slaus, "The nucleon-nucleon interaction", ''J. Phys.'' G 27 (2001) R69 ''(topical review)''.

Kenneth S. Krane, "Introductory Nuclear Physics", (1988) Wiley & Sons ISBN 0-471-80553-X

P. Navrátil and W.E. Ormand, "Ab initio shell model with a genuine three-nucleon force for the p-shell nuclei", Phys. Rev. C 68, 034305 (2003).

Category:Nuclear physics Category:Quantum chromodynamics

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name	Carl Sagan
birth date	November 09, 1934
birth place	Brooklyn, New York City, U.S.
residence	United States
nationality	American
death date	December 20, 1996
death place	Seattle, Washington, U.S.
death cause	Pneumonia
education	Rahway High School
alma mater	University of Chicago,Cornell University
field	Astronomy, Astrophysics, Cosmology, Astrobiology, Space science, Planetary science
work institutions	Cornell University Harvard University Smithsonian Astrophysical Observatory University of California, Berkeley
alma mater	University of Chicago (B.A.), (B.Sc.), (M.Sc.), (Ph.D.)
known for	Search for Extra-Terrestrial Intelligence (SETI) ''Cosmos: A Personal Voyage'' ''Cosmos'' Voyager Golden Record Pioneer plaque ''Contact'' ''Pale Blue Dot''
prizes	Oersted Medal (1990) NASA Distinguished Public Service Medal (twice) Pulitzer Prize for General Non-Fiction (1978) National Academy of Sciences Public Welfare Medal (1994) }}

Carl Edward Sagan () (November 9, 1934 December 20, 1996) was an American astronomer, astrophysicist, cosmologist, author, science popularizer, and science communicator in the space and natural sciences. During his lifetime, he published more than 600 scientific papers and popular articles and was author, co-author, or editor of more than 20 books. In his works, he advocated skeptical inquiry and the scientific method. He pioneered exobiology and promoted the Search for Extra-Terrestrial Intelligence (SETI).

Sagan became world-famous for his popular science books and for the award-winning 1980 television series ''Cosmos: A Personal Voyage'', which he narrated and co-wrote. A book to accompany the program was also published. Sagan also wrote the novel ''Contact'', the basis for the 1997 film of the same name.

Early life

Carl Sagan was born in Brooklyn, New York City, to a Ukrainian Jewish family. His father, Sam Sagan, was an immigrant garment worker from Kamenets-Podolsk, Ukraine; his mother, Rachel Molly Gruber, a housewife. Carl was named in honor of Rachel's biological mother, Chaiya Clara, in Sagan's words, "the mother she never knew." Sagan graduated from Rahway High School in Rahway, New Jersey, in 1951.

He had one sister, Carol, and the family lived in a modest apartment near the Atlantic Ocean, in Bensonhurst, a Brooklyn neighborhood. According to Sagan, they were Reform Jews, the most liberal of the three main Jewish groups. Both Sagan and his sister agree that their father was not especially religious, but that their mother "definitely believed in God, and was active in the temple ... and served only Kosher meat." During the height of the Depression, his father had to accept a job as a theater usher.

According to biographer Keay Davidson, Sagan's "inner war" was a result of his close relations with both his parents, who were in many ways "opposites." Sagan traced his later analytical urges to his mother, a woman who had known "extreme poverty as a child," and had grown up almost homeless in New York City during World War I and the 1920s. She had her own intellectual ambitions as a young woman, but they were blocked by social restrictions, because of her poverty, her being a woman and wife, and her Jewish religion. Davidson notes that she therefore "worshiped her only son, Carl. He would fulfill her unfulfilled dreams."

However, his "sense of wonder" came from his father, who was a "quiet and soft-hearted escapee from the Czar." In his free time, he gave apples to the poor, or helped soothe labor-management tensions within New York's "tumultuous" garment industry. Although he was "awed" by Carl's "brilliance, his boyish chatter about stars and dinosaurs," he took his son's inquisitiveness in stride, as part of his growing up. In his later years as a writer and scientist, Sagan would often draw on his childhood memories to illustrate scientific points, as he did in his book, ''Shadows of Forgotten Ancestors''. Sagan describes his parents' influence on his later thinking:

:''My parents were not scientists. They knew almost nothing about science. But in introducing me simultaneously to skepticism and to wonder, they taught me the two uneasily cohabiting modes of thought that are central to the scientific method.''

1939 World's Fair

Sagan recalls that one of his best experiences was when he was four or five years old, his parents took him to the 1939 New York World's Fair. The exhibits became a turning point in his life. He later recalled the moving map of the "America of Tomorrow" exhibit: "It showed beautiful highways and cloverleaves and little General Motors cars all carrying people to skyscrapers, buildings with lovely spires, flying buttresses — and it looked great!" At other exhibits, he remembered how a flashlight that shined on a photoelectric cell created a cracking sound, and how the sound from a tuning fork became a wave on an oscilloscope. He also witnessed the future media technology that would replace radio: television. Sagan wrote:

:''Plainly, the world held wonders of a kind I had never guessed. How could a tone become a picture and light become a noise?''

He also saw one of the Fair's most publicized events, the burial of a time capsule at Flushing Meadows, which contained mementos of the 1930s to be recovered by Earth's descendants in a future millennium. "The time capsule thrilled Carl," writes Davidson. As an adult, Sagan and his colleagues created similar time capsules, but ones that would be sent out into the galaxy. These were the Pioneer plaque and the ''Voyager Golden Record'' records, all of which were spinoffs of Sagan's memories of the World Fair.

World War II

During World War II, Sagan's family worried about the fate of their European relatives. Sagan, however, was generally unaware of the details of the ongoing war. He writes, "Sure, we had relatives who were caught up in the Holocaust. Hitler was not a popular fellow in our household ... But on the other hand, I was fairly insulated from the horrors of the war." His sister, Carol, said that their mother "above all wanted to protect Carl ... She had an extraordinarily difficult time dealing with World War II and the Holocaust." Sagan's book, ''The Demon-Haunted World'' (1996), included his memories of this conflicted period in his life, where his family dealt with the realities of the war in Europe, but tried to prevent it from undermining his optimistic spirit.

Inquisitiveness about nature

Soon after entering elementary school, he began to express a strong inquisitiveness about nature. Sagan recalled taking his first trips to the public library alone, at the age of five, when his mother got him a library card. He wanted to learn what stars were, since none of his friends or their parents could give him a clear answer: :''I went to the librarian and asked for a book about stars ... And the answer was stunning. It was that the Sun was a star but really close. The stars were suns, but so far away they were just little points of light ... The scale of the universe suddenly opened up to me. It was a kind of religious experience. There was a magnificence to it, a grandeur, a scale which has never left me. Never ever left me.''

About the time he was six or seven, he and a close friend took trips to the American Museum of Natural History in New York City. While there, they went to the Hayden Planetarium and walked around the museum's exhibits of space objects, such as meteorites, and displays of dinosaurs and animals in natural settings. Sagan writes about those visits: :''I was transfixed by the dioramas — lifelike representations of animals and their habitats all over the world. Penguins on the dimly lit Antarctic ice; ... a family of gorillas, the male beating his chest, ... an American grizzly bear standing on his hind legs, ten or twelve feet tall, and staring me right in the eye.''

His parents helped nurture his growing interest in science by buying him chemistry sets and reading materials. His interest in space, however, was his primary focus, especially after reading science fiction stories by writers such as Edgar Rice Burroughs, which stirred his imagination about life on other planets, such as Mars. According to biographer Ray Spangenburg, these early years as Sagan tried to understand the mysteries of the planets, became a "driving force in his life, a continual spark to his intellect, and a quest that would never be forgotten."

Education and scientific career

He attended the University of Chicago, where he participated in the Ryerson Astronomical Society, received a bachelor of arts with general and special honors in 1954, a bachelor of science in 1955, and a master of science in physics in 1956 before earning a PhD in astronomy and astrophysics in 1960. During his time as an undergraduate, Sagan worked in the laboratory of the geneticist H. J. Muller. From 1960 to 1962 Sagan was a Miller Fellow at the University of California, Berkeley. From 1962 to 1968, he worked at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts.

Sagan lectured and did research at Harvard University until 1968, when he moved to Cornell University in Ithaca, New York. He became a full Professor at Cornell in 1971, and he directed the Laboratory for Planetary Studies there. From 1972 to 1981, Sagan was the Associate Director of the Center for Radio Physics and Space Research at Cornell.

Sagan was associated with the American space program from its inception. From the 1950s onward, he worked as an advisor to NASA, where one of his duties included briefing the Apollo astronauts before their flights to the Moon. Sagan contributed to many of the robotic spacecraft missions that explored the solar system, arranging experiments on many of the expeditions. He conceived the idea of adding an unalterable and universal message on spacecraft destined to leave the solar system that could potentially be understood by any extraterrestrial intelligence that might find it. Sagan assembled the first physical message that was sent into space: a gold-anodized plaque, attached to the space probe Pioneer 10, launched in 1972. Pioneer 11, also carrying another copy of the plaque, was launched the following year. He continued to refine his designs; the most elaborate message he helped to develop and assemble was the Voyager Golden Record that was sent out with the Voyager space probes in 1977. Sagan often challenged the decisions to fund the Space Shuttle and Space Station at the expense of further robotic missions.

Sagan taught a course on critical thinking at Cornell University until he died in 1996 from pneumonia, a few months after finding that he was in remission of myelodysplastic syndrome.

Scientific achievements

Sagan's contributions were central to the discovery of the high surface temperatures of the planet Venus. In the early 1960s no one knew for certain the basic conditions of that planet's surface, and Sagan listed the possibilities in a report later depicted for popularization in a Time-Life book, ''Planets''. His own view was that Venus was dry and very hot as opposed to the balmy paradise others had imagined. He had investigated radio emissions from Venus and concluded that there was a surface temperature of . As a visiting scientist to NASA's Jet Propulsion Laboratory, he contributed to the first Mariner missions to Venus, working on the design and management of the project. Mariner 2 confirmed his conclusions on the surface conditions of Venus in 1962.

Sagan was among the first to hypothesize that Saturn's moon Titan might possess oceans of liquid compounds on its surface and that Jupiter's moon Europa might possess subsurface oceans of water. This would make Europa potentially habitable for life. Europa's subsurface ocean of water was later indirectly confirmed by the spacecraft Galileo. Sagan also helped solve the mystery of the reddish haze seen on Titan, revealing that it is composed of complex organic molecules constantly raining down onto the moon's surface.

He further contributed insights regarding the atmospheres of Venus and Jupiter as well as seasonal changes on Mars. Sagan established that the atmosphere of Venus is extremely hot and dense with pressures increasing steadily all the way down to the surface. He also perceived global warming as a growing, man-made danger and likened it to the natural development of Venus into a hot, life-hostile planet through a kind of runaway greenhouse effect. Sagan and his Cornell colleague Edwin Ernest Salpeter speculated about life in Jupiter's clouds, given the planet's dense atmospheric composition rich in organic molecules. He studied the observed color variations on Mars' surface and concluded that they were not seasonal or vegetational changes as most believed but shifts in surface dust caused by windstorms.

Sagan is best known, however, for his research on the possibilities of extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation.

He is also the 1994 recipient of the Public Welfare Medal, the highest award of the National Academy of Sciences for "distinguished contributions in the application of science to the public welfare." He was denied membership in the Academy, reportedly because his media activities made him unpopular with many other scientists.

Sagan's ability to convey his ideas allowed many people to better understand the cosmos — simultaneously emphasizing the value and worthiness of the human race, and the relative insignificance of the Earth in comparison to the universe. He delivered the 1977 series of Royal Institution Christmas Lectures in London. He hosted and, with Ann Druyan, co-wrote and co-produced the highly popular thirteen-part PBS television series ''Cosmos: A Personal Voyage'' modeled on Jacob Bronowski's ''The Ascent of Man''.

Sagan was a proponent of the search for extraterrestrial life. He urged the scientific community to listen with radio telescopes for signals from intelligent extraterrestrial life-forms. So persuasive was he that by 1982 he was able to get a petition advocating SETI published in the journal ''Science'' and signed by 70 scientists including seven Nobel Prize winners. This was a tremendous turnaround in the respectability of this controversial field. Sagan also helped Dr. Frank Drake write the Arecibo message, a radio message beamed into space from the Arecibo radio telescope on November 16, 1974, aimed at informing extraterrestrials about Earth.

Sagan was chief technology officer of the professional planetary research journal ''Icarus'' for twelve years. He co-founded the ''Planetary Society'', the largest space-interest group in the world, with over 100,000 members in more than 149 countries, and was a member of the SETI Institute Board of Trustees. Sagan served as Chairman of the Division for Planetary Science of the American Astronomical Society, as President of the Planetology Section of the American Geophysical Union, and as Chairman of the Astronomy Section of the American Association for the Advancement of Science.

At the height of the Cold War, Sagan became involved in public awareness efforts for the effects of nuclear war when a mathematical climate model suggested that a substantial nuclear exchange could upset the delicate balance of life on Earth. He was one of five authors — the "S" of the "TTAPS" report as the research paper came to be known. He eventually co-authored the scientific paper hypothesizing a global nuclear winter following nuclear war. He also co-authored the book ''A Path Where No Man Thought: Nuclear Winter and the End of the Arms Race'', a comprehensive examination of the phenomenon of nuclear winter.

''Cosmos'' covered a wide range of scientific subjects including the origin of life and a perspective of our place in the universe. The series was first broadcast by the Public Broadcasting Service in 1980, winning an Emmy and a Peabody Award. It has been broadcast in more than 60 countries and seen by over 500 million people, making it the most widely watched PBS program in history. In addition, ''Time'' magazine ran a cover story about Sagan soon after the show broadcast, referring to him as "creator, chief writer and host-narrator of the new public television series Cosmos, [and] takes the controls of his fantasy spaceship."

Sagan also wrote books to popularize science, such as ''Cosmos'', which reflected and expanded upon some of the themes of ''A Personal Voyage'', and became the best-selling science book ever published in English; ''The Dragons of Eden: Speculations on the Evolution of Human Intelligence'', which won a Pulitzer Prize; and ''Broca's Brain: Reflections on the Romance of Science''. Sagan also wrote the best-selling science fiction novel ''Contact'' in 1985, based on a film treatment he wrote with his wife in 1979, but he did not live to see the book's 1997 motion picture adaptation, which starred Jodie Foster and won the 1998 Hugo Award for Best Dramatic Adaption.

thumb|left|Pale Blue Dot: Earth is a bright pixel when photographed from "Voyager 1" six billion kilometers out (past Pluto). Sagan encouraged NASA to generate this image. He wrote a sequel to ''Cosmos,'' ''Pale Blue Dot: A Vision of the Human Future in Space'', which was selected as a notable book of 1995 by ''The New York Times''. He appeared on PBS' Charlie Rose program in January 1995. Sagan also wrote an introduction for the bestselling book by Stephen Hawking, ''A Brief History of Time''. Sagan was also known for his popularization of science, his efforts to increase scientific understanding among the general public, and his positions in favor of scientific skepticism and against pseudoscience, such as his debunking of the Betty and Barney Hill abduction. To mark the tenth anniversary of Sagan's passing, David Morrison, a former student of Sagan, recalled "Sagan's immense contributions to planetary research, the public understanding of science, and the skeptical movement" in ''Skeptical Inquirer''.

Sagan hypothesized in January 1991 that enough smoke from the 1991 Kuwaiti oil fires "might get so high as to disrupt agriculture in much of South Asia ..." He later conceded in ''The Demon-Haunted World'' that this prediction did not turn out to be correct: "it ''was'' pitch black at noon and temperatures dropped 4°–6°C over the Persian Gulf, but not much smoke reached stratospheric altitudes and Asia was spared." A 2007 study noted that modern computer models have been applied to the Kuwait oil fires, finding that individual smoke plumes are not able to loft smoke into the stratosphere, but that smoke from fires covering a large area, like some forest fires or the burning of cities that would be expected to follow a nuclear strike, would loft significant amounts of smoke into the stratosphere.

In his later years Sagan advocated the creation of an organized search for near Earth objects that might impact the Earth. When others suggested creating large nuclear bombs that could be used to alter the orbit of a NEO that was predicted to hit the Earth, Sagan proposed the Deflection Dilemma: If we create the ability to deflect an asteroid away from the Earth, then we also create the ability to deflect an asteroid towards the Earth — providing an evil power with a true doomsday bomb.

Billions and billions

From ''Cosmos'' and his frequent appearances on ''The Tonight Show Starring Johnny Carson'', Sagan became associated with the catchphrase "billions and billions". Sagan stated that he never actually used the phrase in the ''Cosmos'' series. The closest that he ever came was in the book ''Cosmos'', where he talked of "billions ''upon'' billions": }}

However, his frequent use of the word ''billions'', and distinctive delivery emphasizing the "b" (which he did intentionally, in place of more cumbersome alternatives such as "billions with a 'b'", in order to distinguish the word from "millions" in viewers' minds), made him a favorite target of comic performers, including Johnny Carson, Gary Kroeger, Mike Myers, Bronson Pinchot, Penn Jillette, Harry Shearer, and others. Frank Zappa satirized the line in the song "Be In My Video", noting as well "atomic light". Sagan took this all in good humor, and his final book was entitled ''Billions and Billions'' which opened with a tongue-in-cheek discussion of this catchphrase, observing that Carson himself was an amateur astronomer and that Carson's comic caricature often included real science.

The popular perception of his characterization of large cosmic quantities continued to be a sense of wonderment at the vastness of space and time, as in his phrase "The total number of stars in the Universe is larger than all the grains of sand on all the beaches of the planet Earth." However, this famous saying was widely misunderstood, as he was in fact referring to the world being at a "critical branch point in history" as in the following quote from ''Cosmos: A Personal Voyage'', Episode 8: "Journeys in Space and Time":

"Those worlds in space are as countless as all the grains of sand on all the beaches of the earth. Each of those worlds is as real as ours and every one of them is a succession of incidents, events, occurrences which influence its future. Countless worlds, numberless moments, an immensity of space and time. And our small planet at this moment, here we face a critical branch point in history: what we do with our world, right now, will propagate down through the centuries and powerfully affect the destiny of our descendants. It is well within our power to destroy our civilization and perhaps our species as well."

Sagan units

As a humorous tribute to him, a ''sagan'' has been defined as a unit of measurement equal to at least four billion, since the lower bound of a number conforming to the constraint of ''billions and billions'' must be two billion plus two billion.

Social concerns

Sagan believed that the Drake equation, on substitution of reasonable estimates, suggested that a large number of extraterrestrial civilizations would form, but that the lack of evidence of such civilizations highlighted by the Fermi paradox suggests technological civilizations tend to destroy themselves rather quickly. This stimulated his interest in identifying and publicizing ways that humanity could destroy itself, with the hope of avoiding such a cataclysm and eventually becoming a spacefaring species. Sagan's deep concern regarding the potential destruction of human civilization in a nuclear holocaust was conveyed in a memorable cinematic sequence in the final episode of ''Cosmos'', called "Who Speaks for Earth?" Sagan had already resigned from the Air Force Scientific Advisory Board and voluntarily surrendered his top secret clearance in protest over the Vietnam War. Following his marriage to his third wife (novelist Ann Druyan) in June 1981, Sagan became more politically active — particularly in opposing escalation of the nuclear arms race under President Ronald Reagan.

In March 1983, Reagan announced the Strategic Defense Initiative — a multi-billion dollar project to develop a comprehensive defense against attack by nuclear missiles, which was quickly dubbed the "Star Wars" program. Sagan spoke out against the project, arguing that it was technically impossible to develop a system with the level of perfection required, and far more expensive to build than for an enemy to defeat through decoys and other means — and that its construction would seriously destabilize the nuclear balance between the United States and the Soviet Union, making further progress toward nuclear disarmament impossible.

When Soviet leader Mikhail Gorbachev declared a unilateral moratorium on the testing of nuclear weapons, which would begin on August 6, 1985 — the 40th anniversary of the atomic bombing of Hiroshima — the Reagan administration dismissed the dramatic move as nothing more than propaganda, and refused to follow suit. In response, American anti-nuclear and peace activists staged a series of protest actions at the Nevada Test Site, beginning on Easter Sunday in 1986 and continuing through 1987. Hundreds of people were arrested, including Sagan, who was arrested on two separate occasions as he climbed over a chain-link fence at the test site.

Personal life and beliefs

Sagan was married three times — in 1957, to biologist Lynn Margulis, mother of Dorion Sagan and Jeremy Sagan; in 1968, to artist Linda Salzman, mother of Nick Sagan; and in 1981, to author Ann Druyan, mother of Alexandra Rachel (Sasha) Sagan and Samuel Democritus Sagan. His marriage to Druyan continued until his death in 1996.

Isaac Asimov described Sagan as one of only two people he ever met whose intellect surpassed his own. The other, he claimed, was the computer scientist and artificial intelligence expert Marvin Minsky.

Sagan wrote frequently about religion and the relationship between religion and science, expressing his skepticism about the conventional conceptualization of God as a sapient being. For example:

Some people think God is an outsized, light-skinned male with a long white beard, sitting on a throne somewhere up there in the sky, busily tallying the fall of every sparrow. Others — for example Baruch Spinoza and Albert Einstein — considered God to be essentially the sum total of the physical laws which describe the universe. I do not know of any compelling evidence for anthropomorphic patriarchs controlling human destiny from some hidden celestial vantage point, but it would be madness to deny the existence of physical laws.

In another description of his view of God, Sagan emphatically writes:

The idea that God is an oversized white male with a flowing beard who sits in the sky and tallies the fall of every sparrow is ludicrous. But if by God one means the set of physical laws that govern the universe, then clearly there is such a God. This God is emotionally unsatisfying... it does not make much sense to pray to the law of gravity.

Despite his criticism of religion, Sagan denied that he was an atheist, saying "An atheist has to know a lot more than I know. An atheist is someone who knows there is no god. By some definitions atheism is very stupid." In reply to a question in 1996 about his religious beliefs, Sagan answered, "I'm agnostic." Sagan maintained that the idea of a creator of the universe was difficult to prove or disprove and that the only conceivable scientific discovery that could challenge it would be an infinitely old universe. According to his last wife, Ann Druyan, he was not a believer: }}

In 2006, Ann Druyan edited Sagan's 1985 Glasgow ''Gifford Lectures in Natural Theology'' into a book, ''The Varieties of Scientific Experience: A Personal View of the Search for God'', in which he elaborates on his views of divinity in the natural world. Sagan is also widely regarded as a freethinker or skeptic; one of his most famous quotations, in ''Cosmos'', was, "Extraordinary claims require extraordinary evidence" (called the "Sagan Standard" by some). This was based on a nearly identical statement by fellow founder of the Committee for the Scientific Investigation of Claims of the Paranormal, Marcello Truzzi, "An extraordinary claim requires extraordinary proof." This idea originated with Pierre-Simon Laplace (1749–1827), a French mathematician and astronomer who said, "The weight of evidence for an extraordinary claim must be proportioned to its strangeness."

Late in his life, Sagan's books elaborated on his skeptical, naturalistic view of the world. In ''The Demon-Haunted World: Science as a Candle in the Dark'', he presented tools for testing arguments and detecting fallacious or fraudulent ones, essentially advocating wide use of critical thinking and the scientific method. The compilation ''Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium'', published in 1997 after Sagan's death, contains essays written by Sagan, such as his views on abortion, and his widow Ann Druyan's account of his death as a skeptic, agnostic, and freethinker.

Sagan warned against humans' tendency towards anthropocentrism. He was the faculty adviser for the Cornell Students for the Ethical Treatment of Animals. In the ''Cosmos'' chapter "Blues For a Red Planet", Sagan wrote, "If there is life on Mars, I believe we should do nothing with Mars. Mars then belongs to the Martians, even if the Martians are only microbes."

Sagan was a user and advocate of marijuana. Under the pseudonym "Mr. X", he contributed an essay about smoking cannabis to the 1971 book ''Marihuana Reconsidered''. The essay explained that marijuana use had helped to inspire some of Sagan's works and enhance sensual and intellectual experiences. After Sagan's death, his friend Lester Grinspoon disclosed this information to Sagan's biographer, Keay Davidson. The publishing of the biography, ''Carl Sagan: A Life'', in 1999 brought media attention to this aspect of Sagan's life. Not long after his death, widow Ann Druyan had gone on to preside over the board of directors of NORML, a foundation dedicated to reforming cannabis laws.

In 1994, engineers at Apple Computer code-named the Power Macintosh 7100 "Carl Sagan" in the hope that Apple would make "billions and billions" with the sale of the PowerMac 7100. The name was only used internally, but Sagan was concerned that it would become a product endorsement and sent Apple a cease and desist letter. Apple complied, but engineers retaliated by changing the internal codename to "BHA" for "Butt-Head Astronomer". Sagan then sued Apple for libel, a form of defamation, in federal court. The court granted Apple's motion to dismiss Sagan's claims and opined in dicta that a reader aware of the context would understand Apple was "clearly attempting to retaliate in a humorous and satirical way", and that "It strains reason to conclude that Defendant was attempting to criticize Plaintiff's reputation or competency as an astronomer. One does not seriously attack the expertise of a scientist using the undefined phrase 'butt-head'." Sagan then sued for Apple's original use of his name and likeness, but again lost. Sagan appealed the ruling. In November 1995, an out of court settlement was reached and Apple's office of trademarks and patents released a conciliatory statement that "Apple has always had great respect for Dr. Sagan. It was never Apple's intention to cause Dr. Sagan or his family any embarrassment or concern."

Sagan briefly served as an adviser on Stanley Kubrick's film ''2001: A Space Odyssey''. Sagan proposed that the film would suggest, rather than depict, extraterrestrial superintelligence.

Sagan and UFOs

Sagan had some interest in UFO reports from at least 1964 when he had several conversations on the subject with Jacques Vallee. Though quite skeptical of any extraordinary answer to the UFO question, Sagan thought scientists should study the phenomenon, at least because there was widespread public interest in UFO reports.

Stuart Appelle notes that Sagan "wrote frequently on what he perceived as the logical and empirical fallacies regarding UFOs and the abduction experience. Sagan rejected an extraterrestrial explanation for the phenomenon but felt there were both empirical and pedagogical benefits for examining UFO reports and that the subject was, therefore, a legitimate topic of study."

In 1966, Sagan was a member of the Ad Hoc Committee to Review Project Blue Book, the U.S. Air Force's UFO investigation project. The committee concluded Blue Book had been lacking as a scientific study, and recommended a university-based project to give the UFO phenomenon closer scientific scrutiny. The result was the Condon Committee (1966–1968), led by physicist Edward Condon, and in their final report they formally concluded that UFOs, regardless of what any of them actually were, did not behave in a manner consistent with a threat to national security.

Ron Westrum writes that "The high point of Sagan's treatment of the UFO question was the AAAS's symposium in 1969. A wide range of educated opinions on the subject were offered by participants, including not only proponents such as James McDonald and J. Allen Hynek but also skeptics like astronomers William Hartmann and Donald Menzel. The roster of speakers was balanced, and it is to Sagan's credit that this event was presented in spite of pressure from Edward Condon". With physicist Thornton Page, Sagan edited the lectures and discussions given at the symposium; these were published in 1972 as ''UFOs: A Scientific Debate''. Some of Sagan's many books examine UFOs (as did one episode of ''Cosmos'') and he claimed a religious undercurrent to the phenomenon.

Sagan again revealed his views on interstellar travel in his 1980 ''Cosmos'' series. In one of his last written works, Sagan argued that the chances of extraterrestrial spacecraft visiting Earth are vanishingly small. However, Sagan did think it plausible that Cold War concerns contributed to governments misleading their citizens about UFOs, and that "some UFO reports and analyses, and perhaps voluminous files, have been made inaccessible to the public which pays the bills ... It's time for the files to be declassified and made generally available." He cautioned against jumping to conclusions about suppressed UFO data and stressed that there was no strong evidence that aliens were visiting the Earth either in the past or present.

Death

After a long and difficult fight with myelodysplasia, which included three bone marrow transplants, Sagan died of pneumonia at the age of 62 at the Fred Hutchinson Cancer Research Center in Seattle, Washington, on December 20, 1996. He was buried at Lakeview Cemetery in Ithaca, New York.

Posthumous recognition

The 1997 movie ''Contact'', based on Sagan's novel of the same name and finished after his death, ends with the dedication "For Carl".

In 1997, the Sagan Planet Walk was opened in Ithaca New York. It is a walking scale model of the solar system, extending 1.2 km from the center of The Commons in downtown Ithaca, NY, to the Sciencenter, a hands-on museum. The exhibition was created in memory of Carl Sagan, who was an Ithaca resident and Cornell Professor. Professor Sagan had been a founding member of the museum's advisory board.

The landing site of the unmanned Mars Pathfinder spacecraft was renamed the ''Carl Sagan Memorial Station'' on July 5, 1997.

Sagan's son, Nick Sagan, wrote several episodes in the ''Star Trek'' franchise. In an episode of ''Star Trek: Enterprise'' entitled "Terra Prime", a quick shot is shown of the relic rover Sojourner, part of the Mars Pathfinder mission, placed by a historical marker at Carl Sagan Memorial Station on the Martian surface. The marker displays a quote from Sagan: "Whatever the reason you're on Mars, I'm glad you're there, and I wish I was with you." Sagan's student Steve Squyres led the team that landed the Spirit Rover and Opportunity Rover successfully on Mars in 2004.

Asteroid 2709 Sagan is also named in his honor.

On November 9, 2001, on what would have been Sagan's 67th birthday, the NASA Ames Research Center dedicated the site for the Carl Sagan Center for the Study of Life in the Cosmos. "Carl was an incredible visionary, and now his legacy can be preserved and advanced by a 21st century research and education laboratory committed to enhancing our understanding of life in the universe and furthering the cause of space exploration for all time", said NASA Administrator Daniel Goldin. Ann Druyan was at the Center as it opened its doors on October 22, 2006.

Sagan has at least three awards named in his honor:

The Carl Sagan Memorial Award presented jointly since 1997 by the American Astronomical Society (AAS) and the Planetary Society,

The Carl Sagan Medal for Excellence in Public Communication in Planetary Science presented since 1998 by the American Astronomical Society's Division for Planetary Sciences (AAS/DPS) for outstanding communication by an active planetary scientist to the general public — Carl Sagan was one of the original organizing committee members of the DPS, and

The Carl Sagan Award for Public Understanding of Science presented by the Council of Scientific Society Presidents (CSSP) — Sagan himself was the first recipient of the CSSP award in 1993. In 2006, the Carl Sagan Medal was awarded to astrobiologist and author David Grinspoon, the son of Sagan's friend Lester Grinspoon.

On December 20, 2006, the tenth anniversary of Sagan's death, a blogger, Joel Schlosberg, organized a Carl Sagan "blog-a-thon" to commemorate Sagan's death, and the idea was supported by Nick Sagan. Many members of the blogging community participated.

August 2007 the Independent Investigative Group IIG awarded Sagan posthumously a Lifetime Achievement Award. This honor has also been awarded to Harry Houdini and James Randi.

In 2008, Benn Jordan, also known as "The Flashbulb", released the album ''Pale Blue Dot: A Tribute to Carl Sagan''.

In 2009, clips from Carl Sagan's ''Cosmos'' were used as the basis for ''A Glorious Dawn'', the first video produced for the Symphony of Science, an educational music video production by composer John Boswell. Musician Jack White later released this song as a vinyl single under his record label Third Man Records. Additional clips were used in several followup videos which featured Sagan alongside other noted scientists and proponents of rational thinking, such as Richard Dawkins, Richard Feynman, Brian Greene, Lawrence M. Krauss, Bill Nye, and Neil deGrasse Tyson.

In 2010, the 76th anniversary of Carl Sagan's birth, the second "Carl Sagan Day" was celebrated on November 6.

Awards and honors

Annual Award for Television Excellence — 1981 — The Ohio State University — PBS series ''Cosmos''

Apollo Achievement Award — National Aeronautics and Space Administration

NASA Distinguished Public Service Medal — National Aeronautics and Space Administration (twice)

Emmy — Outstanding Individual Achievement — 1981 — PBS series ''Cosmos''

Emmy — Outstanding Informational Series — 1981 — PBS series ''Cosmos''

Exceptional Scientific Achievement Medal — National Aeronautics and Space Administration

Helen Caldicott Leadership Award — Women's Action for Nuclear Disarmament

Hugo Award — 1981 — ''Cosmos''

Humanist of the Year — 1981 — Awarded by the American Humanist Association

In Praise of Reason Award — 1987 — Committee for the Scientific Investigation of Claims of the Paranormal

Isaac Asimov Award — 1994 — Committee for the Scientific Investigation of Claims of the Paranormal

John F. Kennedy Astronautics Award — American Astronautical Society

John W. Campbell Memorial Award — 1974 — ''Cosmic Connection: An Extraterrestrial Perspective''

Joseph Priestley Award — "For distinguished contributions to the welfare of mankind"

Klumpke-Roberts Award of the Astronomical Society of the Pacific — 1974

Konstantin Tsiolkovsky Medal — Awarded by the Soviet Cosmonauts Federation

Locus Award 1986 — ''Contact''

Lowell Thomas Award — Explorers Club — 75th Anniversary

Masursky Award — American Astronomical Society

Miller Research Fellowship — Miller Institute (1960–1962)

Oersted Medal — 1990 — American Association of Physics Teachers

Peabody Award — 1980 — PBS series ''Cosmos''

Prix Galbert — The international prize of Astronautics

Public Welfare Medal — 1994 — National Academy of Sciences

Pulitzer Prize for General Non-Fiction — 1978 — ''The Dragons of Eden''

SF Chronicle Award — 1998 — ''Contact''

Named the "99th Greatest American" on the June 5, 2005, ''Greatest American'' show on the Discovery Channel

Publications

''Planets'' (LIFE Science Library), Sagan, Carl, Jonathan Norton Leonard and editors of Life, Time, Inc., 1966

''Intelligent Life in the Universe'', I.S. Shklovskii coauthor, Random House, 1966, ISBN 1-892803-02-X, 509 pgs (note: republished in 1998 by Emerson-Adams Press)

''UFOs: A Scientific Debate'', Thornton Page coauthor, Cornell University Press, 1972, 310 pgs

''Communication with Extraterrestrial Intelligence''. MIT Press, 1973, 428 pgs

''Mars and the Mind of Man'', Sagan, Carl, et al., Harper & Row, 1973, 143 pgs

''Cosmic Connection: An Extraterrestrial Perspective'', Jerome Agel coauthor, Anchor Press, 1973, ISBN 0-521-78303-8, 301 pgs

''Other Worlds''. Bantam Books, 1975

''Murmurs of Earth: The Voyager Interstellar Record'', Sagan, Carl, et al., Random House, ISBN 0-394-41047-5, 1978

''The Dragons of Eden: Speculations on the Evolution of Human Intelligence''. Ballantine Books, 1978, ISBN 0-345-34629-7, 288 pgs

''Broca's Brain: Reflections on the Romance of Science''. Ballantine Books, 1979, ISBN 0-345-33689-5, 416 pgs

''Cosmos''. Random house, 1980. Random House New Edition, May 7, 2002, ISBN 0-375-50832-5, 384 pgs

''The Cold and the Dark: The World after Nuclear War'', Sagan, Carl et al., Sidgwick & Jackson, 1985

''Comet'', Ann Druyan coauthor, Ballantine Books, 1985, ISBN 0-345-41222-2, 496 pgs

''Contact''. Simon and Schuster, 1985; Reissued August 1997 by Doubleday Books, ISBN 1-56865-424-3, 352 pgs

''A Path Where No Man Thought: Nuclear Winter and the End of the Arms Race'', Richard Turco coauthor, Random House, 1990, ISBN 0-394-58307-8, 499 pgs

''Shadows of Forgotten Ancestors: A Search for Who We Are'', Ann Druyan coauthor, Ballantine Books, October 1993, ISBN 0-345-38472-5, 528 pgs

''Pale Blue Dot: A Vision of the Human Future in Space''. Random House, November 1994, ISBN 0-679-43841-6, 429 pgs

''The Demon-Haunted World: Science as a Candle in the Dark''. Ballantine Books, March 1996, ISBN 0-345-40946-9, 480 pgs (note: the book was first published and copyrighted in 1995 with an errata slip inserted)

''Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium'', Ann Druyan coauthor, Ballantine Books, June 1997, ISBN 0-345-37918-7, 320 pgs

''The Varieties of Scientific Experience: A Personal View of the Search for God'', Carl Sagan (writer) & Ann Druyan (editor), 1985 Gifford lectures, Penguin Press HC, November 2006, ISBN 1-59420-107-2, 304 pgs

References

Further reading

External links

The Carl Sagan Portal

BBC Radio program "Great Lives" on Carl Sagan's life

A Man whose time Has come — Interview with Carl Sagan by Ian Ridpath, New Scientist 1974 July 4

Carl Sagan Prize for Science Popularization

Carl Sagan Medal for Excellence in Public Communication in Planetary Science, presented by the American Astronomical Society's Division for Planetary Sciences (AAS/DPS)

Carl Sagan Center for the Study of Life in the Universe, SETI Institute

Carl Sagan's Life and Legacy as Scientist, Teacher, and Skeptic, Committee for Skeptical Inquiry

Cosmos — Full Episodes and Clips streaming online for free — Hulu, Cosmos online for free

A Tribute to Carl Sagan: Our Place in the Universe, The Skeptics Society

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Name	Richard Feynman
Birth date	May 11, 1918
Birth place	Far Rockaway, Queens, New York, U.S.
Death date	February 15, 1988
Death place	Los Angeles, California, U.S.
Residence	United States
Nationality	American
Fields	Physics
Workplaces	Manhattan ProjectCornell UniversityCalifornia Institute of Technology
Alma mater	Massachusetts Institute of Technology (B.S.),Princeton University (Ph.D.)
Doctoral advisor	John Archibald Wheeler
Academic advisors	Manuel Sandoval Vallarta
Doctoral students	F. L. Vernon, Jr.Willard H. WellsAl HibbsGeorge ZweigGiovanni Rossi LomanitzThomas Curtright
Notable students	Douglas D. OsheroffRobert BarroW. Daniel Hillis
Known for	Feynman diagramsFeynman pointFeynman–Kac formulaFeynman sprinklerFeynman Long Division PuzzlesHellmann–Feynman theoremFeynman slash notationFeynman parametrizationSticky bead argumentOne-electron universeQuantum cellular automata
Influences	Paul Dirac
Spouse	Arline Greenbaum (1941-1945)Mary Lou Bell (1952-1954)Gweneth Howarth (1960-1989)
Awards	Albert Einstein Award (1954) Nobel Prize in Physics (1965)Oersted Medal (1972)
Religion	Atheist
Signature	Richard Feynman signature.svg
Footnotes	He was the father of Carl Feynman and adoptive father of Michelle Feynman. He was the brother of Joan Feynman. }}

Richard Phillips Feynman (; May 11, 1918 – February 15, 1988) was an American physicist known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics (he proposed the parton model). For his contributions to the development of quantum electrodynamics, Feynman, jointly with Julian Schwinger and Sin-Itiro Tomonaga, received the Nobel Prize in Physics in 1965. He 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, Feynman became one of the best-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. He held the Richard Chace Tolman professorship in theoretical physics at the California Institute of Technology.

Feynman was a keen popularizer of physics through both 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 also became known through his semi-autobiographical books (''Surely You're Joking, Mr. Feynman!'' and ''What Do You Care What Other People Think?'') and books written about him, such as ''Tuva or Bust!''

Feynman also had a deep interest in biology, and was a friend of the geneticist and microbiologist Esther Lederberg, who developed replica plating and discovered bacteriophage lambda. They had several mutual physicist friends who, after beginning their careers in nuclear research, moved for moral reasons into genetics, among them Max Delbruck, Leó Szilárd, Guido Pontecorvo, and Aaron Novick.

Biography

Early life

Richard Phillips Feynman was born on May 11, 1918, in Far Rockaway, Queens, New York. His family originated from Russia and Poland; both of his parents were Jewish. They were not religious and by his youth Feynman described himself as an "avowed atheist". Feynman (in common with the famous physicist Edward Teller) was a late talker; by his third birthday he had yet to utter a single word. The young Feynman was heavily influenced by his father, Melville, who encouraged him to ask questions to challenge orthodox thinking. From his mother, Lucille, he gained the sense of humor that he had throughout his life. As a child, he delighted in repairing radios and had a talent for engineering. His younger sister Joan also became a professional physicist.

Education

In high school, his IQ was determined to be 125—high, but "merely respectable" according to biographer James Gleick. Feynman later scoffed at psychometric testing. By 15, he had learned differential and integral calculus. Before entering college, he was experimenting with and re-creating mathematical topics, such as the half-derivative, utilizing his own notation. In high school, he was developing the mathematical intuition behind his Taylor series of mathematical operators. A member of the Arista Honor Society, in his last year in high school, Feynman won the New York University Math Championship; the large difference between his score and those of his closest competitors shocked the judges.

He applied to Columbia University, but was not accepted. Instead he attended the Massachusetts Institute of Technology, where he received a bachelor's degree in 1939, and in the same year was named a Putnam Fellow. While there, Feynman took every physics course offered, including a graduate course on theoretical physics while only in his second year.

He obtained a perfect score on the graduate school entrance exams to Princeton University in mathematics and physics—an unprecedented feat—but did rather poorly on the history and English portions. Attendees at Feynman's first seminar included Albert Einstein, Wolfgang Pauli, and John von Neumann. He received a Ph.D. from Princeton in 1942; his thesis advisor was John Archibald Wheeler. Feynman's thesis applied the principle of stationary action to problems of quantum mechanics, inspired by a desire to quantize the Wheeler–Feynman absorber theory of electrodynamics, laying the groundwork for the "path integral" approach and Feynman diagrams, and was entitled "The Principle of Least Action in Quantum Mechanics".

The Manhattan Project

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 developed their own bomb.

He was assigned to Hans Bethe's theoretical division, and impressed Bethe enough to be made a group leader. He and Bethe 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 or welder's lenses 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, later went on to co-write the computer language BASIC). Later, with Nicholas Metropolis, he assisted in establishing the system for using IBM punched 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.

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 devising safety procedures for material storage so that criticality accidents (for example, due to sub-critical amounts of fissile material inadvertently stored 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 not to be feasible.

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 Feynman's own words, "There wasn't anything to ''do'' there". Bored, he 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 a real spy for the Soviets, transporting nuclear secrets in his car to Santa Fe.

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 after the war to work at the University of California, Berkeley.

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 US. 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."

Early academic career

Following the completion of his Ph.D. in 1942, Feynman held an appointment at the University of Wisconsin–Madison as an assistant professor of physics. The appointment was spent on leave for his involvement in the Manhattan project. In 1945, he received a letter from Dean Mark Ingraham of the College of Letters and Science requesting his return to UW to teach in the coming academic year. His appointment was not extended when he did not commit to return. In a talk given several years later at UW, Feynman quipped, "It's great to be back at the only university that ever had the good sense to fire me".

After the war, Feynman declined an offer from the Institute for Advanced Study in Princeton, New Jersey, despite the presence there of such distinguished faculty members as Albert Einstein, Kurt Gödel, and John von Neumann. Feynman followed Hans Bethe, instead, to Cornell University, where Feynman taught theoretical physics from 1945 to 1950. During a temporary depression following the destruction of Hiroshima by the bomb produced by the Manhattan Project, he focused on complex physics problems, not for utility, but for self-satisfaction. One of these was analyzing the physics of a twirling, nutating dish as it is moving through the air. His work during this period, which used equations of rotation to express various spinning speeds, soon proved important to his Nobel Prize-winning work. Yet because he felt burned out, and had turned his attention to less immediately practical but more entertaining problems, he felt surprised by the offers of professorships from renowned universities. He gained a reputation for taking great care when giving explanations to his students and for making it 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, for 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.

Caltech years

Feynman did significant work while at Caltech, including research in:

Quantum electrodynamics. The theory for which Feynman won his Nobel Prize is known for its accurate predictions. This theory was begun in the earlier years during Feynman's work at Princeton as a graduate student and continued while he was at Cornell. This work consisted of two distinct formulations, and it is a common error to confuse them or to merge them into one. The first is his path integral formulation, and the second is his Feynman diagrams. Both formulations contained his sum over histories method in which every possible path from one state to the next is considered, the final path being a ''sum'' over the possibilities (also referred to as sum-over-paths.) For a number of years he lectured to students at Caltech on his path integral formulation of quantum theory. The lecture notes have recently and very lovingly been reedited by Daniel F. Styer and published as a Dover paperback. Not only did Styer correct several hundred typographical and other minor errors, but he included many footnotes explaining, for example, several places where the author used heuristic or plausible reasoning. The second formulation of quantum electrodynamics (using Feynman diagrams) was specifically mentioned by the Nobel committee. The logical connection with the path integral formulation is interesting. Feynman did not prove that the rules for his diagrams followed mathematically from the path integral formulation. Some special cases were later proved by other people, but only in the real case, so the proofs don't work when spin is involved. The second formulation should be thought of as starting anew, but guided by the intuitive insight provided by the first formulation. Freeman Dyson published a paper in 1949 which, among many other things, added new rules to Feynman's which told how to actually implement Renormalization. Students everywhere learned and used the powerful new tool that Feynman had created. Eventually computer programs were written to compute Feynman diagrams, providing a tool of unprecedented power. It is possible to write such programs because the Feynman diagrams constitute a Formal language with a grammar.

Physics of the superfluidity of supercooled liquid helium, where helium seems to display a complete lack of viscosity when flowing. Applying the Schrödinger equation to the question showed that the superfluid was displaying quantum mechanical behavior observable on a macroscopic scale. This helped with the problem of superconductivity; however, the solution eluded Feynman. It was solved with the BCS theory of superconductivity, proposed by John Bardeen, Leon Neil Cooper, and John Robert Schrieffer.

A model of weak decay, which showed that the current coupling in the process is a combination of vector and axial currents (an example of weak decay is the decay of a neutron into an electron, a proton, and an anti-neutrino). Although E. C. George Sudarshan and Robert Marshak developed the theory nearly simultaneously, Feynman's collaboration with Murray Gell-Mann was seen as seminal because the weak interaction was neatly described by the vector and axial currents. It thus combined the 1933 beta decay theory of Enrico Fermi with an explanation of parity violation.

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'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. Feynman famously painted Feynman diagrams on the exterior of his van.

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". In the mid 1960s, physicists believed that quarks were just a bookkeeping device for symmetry numbers, not real particles, as the statistics of the Omega-minus particle, if it were interpreted as three identical strange quarks bound together, seemed impossible if quarks were real. The Stanford linear accelerator deep inelastic scattering experiments of the late 1960s showed, analogously to Ernest Rutherford's experiment of scattering alpha particles on gold nuclei in 1911, that nucleons (protons and neutrons) contained point-like particles which scattered electrons. It was natural to identify these with quarks, but Feynman's parton model attempted to interpret the experimental data in a way which did not introduce additional hypotheses. For example, the data showed that some 45% of the energy momentum was carried by electrically neutral particles in the nucleon. These electrically neutral particles are now seen to be the gluons which carry the forces between the quarks and carry also the three-valued color quantum number which solves the Omega-minus problem. Feynman did not dispute the quark model; for example, when the fifth quark was discovered in 1977, 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. However, the computational device that Feynman discovered then for gravity, "ghosts", which are "particles" in the interior of his diagrams which have the "wrong" connection between spin and statistics, have proved invaluable in explaining the quantum particle behavior of the Yang–Mills theories, for example QCD and the electro-weak theory.

In 1965, Feynman was appointed a foreign member of the Royal Society. At this time in the early 1960s, Feynman exhausted himself by working on multiple major projects at the same time, including a request, while at Caltech, to "spruce up" the teaching of undergraduates. After three years devoted to the task, he produced a series of lectures that eventually became 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 could be made 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 1984–86, he developed a variational method for the approximate calculation of path integrals which has led to a powerful method of converting divergent perturbation expansions into convergent strong-coupling expansions (variational perturbation theory) and, as a consequence, to the most accurate determination of critical exponents measured in satellite experiments.

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.

Feynman diagrams are now fundamental for string theory and M-theory, and have even been extended topologically. The ''world-lines'' of the diagrams have developed to become ''tubes'' to allow better modeling of more complicated objects such as ''strings'' and ''membranes''. However, 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.

Challenger disaster

Feynman played an important role on the Presidential Rogers Commission, which investigated the ''Challenger'' disaster. 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. He concluded that the NASA management's space shuttle reliability estimate was fantastically unrealistic. He warned in his appendix to the commission's report, "For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." He also rebuked some mathematicians for their exclusivity, saying "I have great suspicion that [mathematicians] don't know, that this stuff is wrong, and that they're intimidating people."

Personal life

While researching for his Ph.D., Feynman married his first wife, Arline Greenbaum (often spelled ''Arlene''). She was diagnosed with tuberculosis, but she and Feynman were careful, and he never contracted it. She succumbed to the disease in 1945. This portion of Feynman's life was portrayed in the 1996 film ''Infinity'', which featured Feynman's daughter Michelle in a cameo role.

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, who shared his enthusiasm for life and spirited adventure. Besides their home in Altadena, California, they had a beach house in Baja California, purchased with the prize money from Feynman's Nobel Prize, his one third share of $55,000. They remained married until Feynman's death. They had a son, Carl, in 1962, and adopted a daughter, Michelle, in 1968. 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 co-worker characterized Feynman as akin to Don Quixote at his desk, rather than at a computer workstation, ready to do battle with the windmills.

Feynman traveled a great deal, notably to Brazil, where he gave courses at the CBPF (Brazilian Center for Physics Research) and near the end of his life schemed to visit the Russian land of Tuva, a dream that, because of 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. 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 successful journey there by his friends.

Responding to Hubert Humphrey's congratulation for his Nobel Prize, Feynman admitted to a long admiration for the then vice president. In a letter to an MIT professor dated December 6, 1966, Feynman expressed interest in running for the governor of California.

Feynman 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 a metal percussion instrument (''frigideira'') in a samba style in Brazil, and participated in a samba school.

In addition, he had some degree of synesthesia for equations, explaining that the letters in certain mathematical functions appeared in color for him, even though invariably printed in standard black-and-white.

According to ''Genius'', the James Gleick–authored biography, Feynman tried LSD during his professorship at Caltech. Somewhat embarrassed by his actions, Feynman largely sidestepped the issue when dictating his anecdotes; he mentions it in passing in the "O Americano, Outra Vez" section, while 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.

Death

Feynman developed two rare forms of cancer, Liposarcoma and Waldenström's macroglobulinemia, dying shortly after a final attempt at surgery for the former on February 15, 1988, aged 69. His last recorded words are noted as "I'd hate to die twice. It's so boring."

Popular legacy

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 stamps were designed by artist Victor Stabin under the direction of U.S. Postal Service art director Carl T. Herrman.

The main building for the Computing Division at Fermilab is named the "Feynman Computing Center" in his honor.

The principal character in Thomas A. McMahon's well-regarded 1970 novel, ''Principles of American Nuclear Chemistry: A Novel'', is modeled on Feynman.

Real Time Opera premiered its opera ''Feynman'' at the Norfolk (CT) Chamber Music Festival in June 2005.

On the 20th anniversary of Feynman's death, composer Edward Manukyan dedicated a piece for solo clarinet to his memory. It was premiered by Doug Storey, the principal clarinetist of the Amarillo Symphony.

In 2009 and 2010, respectively, clips of an interview with Feynman were used by composer John Boswell as part of the Symphony of Science project in the second and fifth installment of his science educational videos, "We Are All Connected" and "The Poetry of Reality".

In 1998, a photo of Richard Feynman giving a lecture was part of the poster series commissioned by Apple Computer for their "Think Different" advertising campaign.

Bibliography

Selected scientific works

Textbooks and lecture notes

''The Feynman Lectures on Physics'' is perhaps his most accessible work for anyone with an interest in physics, compiled from lectures to Caltech undergraduates in 1961–64. As news of the lectures' lucidity grew, a number of professional physicists and graduate students began to drop in to listen. Co-authors Robert B. Leighton and Matthew Sands, colleagues of Feynman, edited and illustrated them into book form. The work has endured, and is useful to this day. They were edited and supplemented in 2005 with "Feynman's Tips on Physics: A Problem-Solving Supplement to the Feynman Lectures on Physics" by Michael Gottlieb and Ralph Leighton (Robert Leighton's son), with support from Kip Thorne and other physicists.

Includes ''Feynman's Tips on Physics'' (with Michael Gottlieb and Ralph Leighton), which includes four previously unreleased lectures on problem solving, exercises by Robert Leighton and Rochus Vogt, and a historical essay by Matthew Sands.

Popular works

''Surely You're Joking, Mr. Feynman!'': Adventures of a Curious Character, with contributions by Ralph Leighton, W. W. Norton & Co, 1985, ISBN 0-393-01921-7.

''What Do You Care What Other People Think?'': Further Adventures of a Curious Character, with contributions by Ralph Leighton, W. W. Norton & Co, 1988, ISBN 0-393-02659-0.

''No Ordinary Genius: The Illustrated Richard Feynman'', ed. Christopher Sykes, W. W. Norton & Co, 1996, ISBN 039331393X.

''Six Easy Pieces: Essentials of Physics Explained by Its Most Brilliant Teacher'', Perseus Books, 1994, ISBN 0-201-40955-0.

''Six Not So Easy Pieces: Einstein's Relativity, Symmetry and Space-Time'', Addison Wesley, 1997, ISBN 0-201-15026-3.

''The Meaning of It All: Thoughts of a Citizen Scientist'', Perseus Publishing, 1999, ISBN 0738201669.

''The Pleasure of Finding Things Out: The Best Short Works of Richard P. Feynman'', edited by Jeffrey Robbins, Perseus Books, 1999, ISBN 0738201081.

''Classic Feynman: All the Adventures of a Curious Character'', edited by Ralph Leighton, W. W. Norton & Co, 2005, ISBN 0-393-06132-9. Chronologically reordered omnibus volume of ''Surely You're Joking, Mr. Feynman!'' and ''What Do You Care What Other People Think?'', with a bundled CD containing one of Feynman's signature lectures.

Audio and video recordings

''Safecracker Suite'' (a collection of drum pieces interspersed with Feynman telling anecdotes)

''Los Alamos From Below'' (talk given by Feynman at Santa Barbara on February 6, 1975)

''Six Easy Pieces'' (original lectures upon which the book is based)

''Six Not So Easy Pieces'' (original lectures upon which the book is based)

The Feynman Lectures on Physics: The Complete Audio Collection

Samples of Feynman's drumming, chanting and speech are included in the songs "Tuva Groove (Bolur Daa-Bol, Bolbas Daa-Bol)" and "Kargyraa Rap (Dürgen Chugaa)" on the album ''Back Tuva Future, The Adventure Continues'' by Kongar-ool Ondar. The hidden track on this album also includes excerpts from lectures without musical background.

The Messenger Lectures, given at Cornell in 1964, in which he explains basic topics in physics. Available on Project Tuva for free (See also the book ''The Character of Physical Law'')

Take the world from another point of view [videorecording] / with Richard Feynman; Films for the Hu (1972)

The Douglas Robb Memorial Lectures Four public lectures of which the four chapters of the book QED: The Strange Theory of Light and Matter are transcripts. (1979)

The Pleasure of Finding Things Out (1981) (not to be confused with the later published book of same title)

Richard Feynman: Fun to Imagine Collection, BBC Archive of 6 short films of Feynman talking in a style that is accessible to all about the physics behind common to all experiences. (1983)

''Elementary Particles and the Laws of Physics'' (1986)

''The Last Journey of a Genius'', a BBC TV production in association with WGBH Boston (1989)

See also

Feynman diagram

Feynman checkerboard

Flexagon

Foresight Nanotech Institute Feynman Prize

List of physicists

List of theoretical physicists

Negative probability

One-electron universe

Stückelberg–Feynman interpretation

Wheeler–Feynman absorber theory

Notes

References

, foreword by Timothy Ferris. (Published in the UK under the title: ''Don't You Have Time to Think?'', with additional commentary by Michelle Feynman, Allen Lane, 2005, ISBN 0-7139-9847-4.)

Further reading

Articles

''Physics Today'', American Institute of Physics magazine, February 1989 Issue. (Vol.42, No.2.) Special Feynman memorial issue containing non-technical articles on Feynman's life and work in physics.

Books

Brown, Laurie M. and Rigden, John S. (editors) (1993) ''Most of the Good Stuff: Memories of Richard Feynman'' Simon and Schuster, New York, ISBN 0883188708. Commentary by Joan Feynman, John Wheeler, Hans Bethe, Julian Schwinger, Murray Gell-Mann, Daniel Hillis, David Goodstein, Freeman Dyson, and Laurie Brown

Dyson, Freeman (1979) ''Disturbing the Universe''. Harper and Row. ISBN 0-06-011108-9. Dyson's autobiography. The chapters "A Scientific Apprenticeship" and "A Ride to Albuquerque" describe his impressions of Feynman in the period 1947–48 when Dyson was a graduate student at Cornell

Gleick, James (1992) ''Genius: The Life and Science of Richard Feynman''. Pantheon. ISBN 0679747044

Krauss, Lawrence M. (2011) ''Quantum Man: Richard Feynman's Life in Science''. W.W. Norton & Company. 350 pages, biography. ISBN 0393064719,

LeVine, Harry, III (2009) ''The Great Explainer: The Story of Richard Feynman'' (''Profiles in Science'' series) Morgan Reynolds, Greensboro, North Carolina, ISBN 978-1-59935-113-1; for high school readers

Mehra, Jagdish (1994) ''The Beat of a Different Drum: The Life and Science of Richard Feynman''. Oxford University Press. ISBN 0-19-853948-7

Gribbin, John and Gribbin, Mary (1997) ''Richard Feynman: A Life in Science''. Dutton, New York, ISBN 052594124X

Milburn, Gerard J. (1998) ''The Feynman Processor: Quantum Entanglement and the Computing Revolution'' Perseus Books, ISBN 0-7382-0173-1

Mlodinow, Leonard (2003) ''Feynman's Rainbow: A Search For Beauty In Physics And In Life'' Warner Books. ISBN 0-446-69251-4 Published in the United Kingdom as ''Some Time With Feynman''

Schweber, Silvan S. (1994) "Chapter 8: Richard Feynman and the Visualization of Space-Time Processes" ''QED and the Men Who Made It: Dyson, Feynman, Schwinger, and Tomonaga'' (Princeton Series in Physics) Princeton University Press, Princeton, New Jersey, pp. 373–473, ISBN 0691036853

Sykes, Christopher, ed., (1994) ''No Ordinary Genius: The Illustrated Richard Feynman''. W W Norton & Co. Inc. ISBN 0393036219

Films and plays

''Infinity'', a movie directed by Matthew Broderick and starring Matthew Broderick as Feynman, depicting Feynman's love affair with his first wife and ending with the Trinity test. 1996.

Parnell, Peter (2002) "QED" Applause Books, ISBN 978-1557835925, (play).

Whittell, Crispin (2006) "Clever Dick" Oberon Books, (play)

"The Pleasure of Finding Things Out" A film documentary autobiography of Richard Feynman, Nobel laureate and theoretical physicist extraordinary. 1982, BBC TV 'Horizon' and PBS 'Nova' (50 mins film). See Christopher Sykes Productions http://www.sykes.easynet.co.uk/

"The Quest for Tannu Tuva", with Richard Feynman and Ralph Leighton. 1987, BBC TV 'Horizon' and PBS 'Nova' (under the title "Last Journey of a Genius") (50 mins film)

"No Ordinary Genius" A two-part documentary about Feynman's life and work, with contributions from colleagues, friends and family. 1993, BBC TV 'Horizon' and PBS 'Nova' (a one-hour version, under the title "The Best Mind Since Einstein") (2 x 50 mins films)

External links

About Richard Feynman

Leonard Susskind">14 minute talk about Dick Feynman by his friend Leonard Susskind

Gallery of Drawings by Richard P. Feynman

Biography and Bibliographic Resources, from the Office of Scientific and Technical Information, United States Department of Energy

MIT OpenCourseWare STS.042J / 8.225J : Einstein, Oppenheimer, Feynman: Physics in the 20th Century Free, independent study course that explores the changing roles of physics and physicists during the 20th century.

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