Leo Szilard (/ˈsɪlɑːrd/; Hungarian: Szilárd Leó [ˈsilaːrd ˈlɛoː]; born Leó Spitz; February 11, 1898 – May 30, 1964) was a Hungarian-German-American physicist and inventor. He conceived the nuclear chain reaction in 1933, patented the idea of a nuclear reactor with Enrico Fermi in 1934, and in late 1939 wrote the letter for Albert Einstein's signature that resulted in the Manhattan Project that built the atomic bomb.
Szilard initially attended Palatine Joseph Technical University in Budapest, but his engineering studies were interrupted by service in the Austro-Hungarian Army during World War I. He left Hungary for Germany in 1919, enrolling at Technische Hochschule (Institute of Technology) in Berlin-Charlottenburg, but became bored with engineering and transferred to Friedrich Wilhelm University, where he studied physics. He wrote his doctoral thesis on Maxwell's demon, a long-standing puzzle in the philosophy of thermal and statistical physics. Szilard was the first to recognize the connection between thermodynamics and information theory.
In addition to the nuclear reactor, Szilard submitted patent applications for a linear accelerator in 1928, and a cyclotron in 1929. He also conceived the idea of an electron microscope. Between 1926 and 1930, he worked with Einstein on the development of the Einstein refrigerator. After Adolf Hitler became chancellor of Germany in 1933, Szilard urged his family and friends to flee Europe while they still could. He moved to England, where he helped found the Academic Assistance Council, an organization dedicated to helping refugee scholars find new jobs. While in England he discovered a means of isotope separation known as the Szilard–Chalmers effect.
Foreseeing another war in Europe, Szilard moved to the United States in 1938, where he worked with Enrico Fermi and Walter Zinn on means of creating a nuclear chain reaction. He was present when this was achieved on December 2, 1942. He worked for the Manhattan Project's Metallurgical Laboratory on aspects of nuclear reactor design. He drafted the Szilard petition advocating a demonstration of the atomic bomb, but the Interim Committee chose to use them against cities without warning.
After the war, Szilard switched to biology. He invented the chemostat, discovered feedback inhibition, and was involved in the first cloning of a human cell. He publicly sounded the alarm against the possible development of salted thermonuclear bombs, a new kind of nuclear weapon that might annihilate mankind. Diagnosed with bladder cancer in 1960, he underwent a cobalt-60 treatment that he had designed. He helped found the Salk Institute for Biological Studies, where he became a resident fellow. Szilard founded Council for a Livable World in 1962 to deliver "the sweet voice of reason" about nuclear weapons to Congress, the White House, and the American public. He died in his sleep of a heart attack in 1964. According to György Marx he was one of The Martians.
Szilard, c. 1960
|Born||February 11, 1898|
|Died||May 30, 1964 (aged 66)|
La Jolla, California, United States
|Residence||Hungary, Germany, United Kingdom, United States|
|Awards||Atoms for Peace Award (1959)|
Albert Einstein Award (1960)
|Thesis||Über die thermodynamischen Schwankungserscheinungen (1923)|
|Doctoral advisor||Max von Laue|
|Other academic advisors||Albert Einstein|
Born as Leó Spitz in Budapest, Kingdom of Hungary, on February 11, 1898. His middle-class Jewish parents, Louis Spitz, a civil engineer, and Tekla Vidor, raised Leó on the Városligeti Fasor in Pest. He had two younger siblings, a brother, Béla, born in 1900, and a sister, Rózsi (Rose), born in 1901. On October 4, 1900, the family changed its surname from the German "Spitz" to the Hungarian "Szilárd", a name that means "solid" in Hungarian. Despite having a religious background, Szilard became an agnostic. From 1908 to 1916 he attended Reáliskola high school in his home town. Showing an early interest in physics and a proficiency in mathematics, in 1916 he won the Eötvös Prize, a national prize for mathematics.
With World War I raging in Europe, Szilard received notice on January 22, 1916, that he had been drafted into the 5th Fortress Regiment, but he was able to continue his studies. He enrolled as an engineering student at the Palatine Joseph Technical University, which he entered in September 1916. The following year he joined the Austro-Hungarian Army's 4th Mountain Artillery Regiment, but immediately was sent to Budapest as an officer candidate. He rejoined his regiment in May 1918 but in September, before being sent to the front, he fell ill with Spanish Influenza and was returned home for hospitalization. Later he was informed that his regiment had been nearly annihilated in battle, so the illness probably saved his life. He was discharged honorably in November 1918, after the Armistice.
In January 1919, Szilard resumed his engineering studies, but Hungary was in a chaotic political situation with the rise of the Hungarian Soviet Republic under Béla Kun. Szilard and his brother Béla founded their own political group, the Hungarian Association of Socialist Students, with a platform based on a scheme of Szilard's for taxation reform. He was convinced that socialism was the answer to Hungary's post-war problems, but not that of Kun's Hungarian Socialist Party, which had close ties to the Soviet Union. When Kun's government tottered, the brothers officially changed their religion from "Israelite" to "Calvinist", but when they attempted to re-enroll in what was now the Budapest University of Technology, they were prevented from doing so by nationalist students because they were Jews.
Convinced that there was no future for him in Hungary, Szilard left for Berlin via Austria on December 25, 1919, and enrolled at the Technische Hochschule (Institute of Technology) in Berlin-Charlottenburg. He was soon joined by his brother Béla. Szilard became bored with engineering, and his attention turned to physics. This was not taught at the Technische Hochschule, so he transferred to Friedrich Wilhelm University, where he attended lectures given by Albert Einstein, Max Planck, Walter Nernst, James Franck and Max von Laue. He also met fellow Hungarian students Eugene Wigner, John von Neumann and Dennis Gabor. His doctoral dissertation on thermodynamics Über die thermodynamischen Schwankungserscheinungen (On The Manifestation of Thermodynamic Fluctuations), praised by Einstein, won top honors in 1922. It involved a long-standing puzzle in the philosophy of thermal and statistical physics known as Maxwell's demon, a thought experiment originated by the physicist James Clerk Maxwell. The problem was thought to be insoluble, but in tackling it Szilard recognized the connection between thermodynamics and information theory.
Szilard was appointed as assistant to von Laue at the Institute for Theoretical Physics in 1924. In 1927 he finished his habilitation and became a Privatdozent (private lecturer) in physics. For his habilitation lecture, he produced a second paper on Maxwell's Demon, Über die Entropieverminderung in einem thermodynamischen System bei Eingriffen intelligenter Wesen (On the reduction of entropy in a thermodynamic system by the intervention of intelligent beings), that had actually been written soon after the first. This introduced the thought experiment now called the Szilard engine and became important in the history of attempts to understand Maxwell's demon. The paper is also the first equation of negative entropy and information. As such, it established Szilard as one of the founders of information theory, but he did not publish it until 1929, and did not pursue it further. Claude E. Shannon, who took it up in the 1950s, acknowledged Szilard's paper as his starting point.
Throughout his time in Berlin, Szilard worked on numerous technical inventions. In 1928 he submitted a patent application for the linear accelerator, not knowing of Gustav Ising's prior 1924 journal article and Rolf Widerøe's operational device, and in 1929 applied for one for the cyclotron. He also conceived the electron microscope. Between 1926 and 1930, he worked with Einstein to develop the Einstein refrigerator, notable because it had no moving parts. He did not build all of these devices, or publish these ideas in scientific journals, and so credit for them often went to others. As a result, Szilard never received the Nobel Prize, but Ernest Lawrence was awarded it for the cyclotron in 1939 and Ernst Ruska for the electron microscope in 1986.
Szilard received German citizenship in 1930, but was already uneasy about the political situation in Europe. When Adolf Hitler became chancellor of Germany on January 30, 1933, Szilard urged his family and friends to flee Europe while they still could. He moved to England, and transferred his savings of £1,595 (£111,200 today) from his bank in Zurich to one in London. He lived in hotels where lodging and meals cost about £5/5 a week. For those less fortunate, he helped found the Academic Assistance Council, an organization dedicated to helping refugee scholars find new jobs, and persuaded the Royal Society to provide accommodation for it at Burlington House. He enlisted the help of academics such as Harald Bohr, G. H. Hardy, Archibald Hill and Frederick G. Donnan. By the outbreak of World War II in 1939, it had helped to find places for over 2,500 refugee scholars.
On the morning of September 12, 1933, Szilard read an article in The Times summarizing a speech given by Lord Rutherford in which Rutherford rejected the feasibility of using atomic energy for practical purposes. The speech remarked specifically on the recent 1932 work of his students, John Cockcroft and Ernest Walton, in "splitting" lithium into alpha particles, by bombardment with protons from a particle accelerator they had constructed. Rutherford went on to say:
We might in these processes obtain very much more energy than the proton supplied, but on the average we could not expect to obtain energy in this way. It was a very poor and inefficient way of producing energy, and anyone who looked for a source of power in the transformation of the atoms was talking moonshine. But the subject was scientifically interesting because it gave insight into the atoms. 
Szilard was so annoyed at Rutherford's dismissal that, on the same day, he conceived of the idea of nuclear chain reaction (analogous to a chemical chain reaction), using recently discovered neutrons. The idea did not use the mechanism of nuclear fission, which was not yet discovered, but Szilard realized that if neutrons could initiate any sort of energy-producing nuclear reaction, such as the one that had occurred in lithium, and could be produced themselves by the same reaction, energy might be obtained with little input, since the reaction would be self-sustaining. The following year he filed for a patent on the concept of the neutron-induced nuclear chain reaction. Richard Rhodes described Szilard's moment of inspiration:
In London, where Southampton Row passes Russell Square, across from the British Museum in Bloomsbury, Leo Szilard waited irritably one gray Depression morning for the stoplight to change. A trace of rain had fallen during the night; Tuesday, September 12, 1933, dawned cool, humid and dull. Drizzling rain would begin again in early afternoon. When Szilard told the story later he never mentioned his destination that morning. He may have had none; he often walked to think. In any case another destination intervened. The stoplight changed to green. Szilard stepped off the curb. As he crossed the street time cracked open before him and he saw a way to the future, death into the world and all our woes, the shape of things to come.
In early 1934, Szilard began working at St Bartholomew's Hospital in London. Working with a young physicist on the hospital staff, Thomas A. Chalmers, he began studying radioactive isotopes for medical purposes. It was known that bombarding elements with neutrons could produce either heavier isotopes of an element, or a heavier element, a phenomenon known as the Fermi Effect after its discoverer, the Italian physicist Enrico Fermi. When they bombarded ethyl iodide with neutrons produced by a radon–beryllium source, they found that the heavier radioactive isotopes of iodine separated from the compound. Thus, they had discovered a means of isotope separation. This method became known as the Szilard–Chalmers effect, and was widely used in the preparation of medical isotopes. He also attempted unsuccessfully to create a nuclear chain reaction using beryllium by bombarding it with X-rays. In 1936, Szilard assigned his chain-reaction patent to the British Admiralty to ensure its secrecy.
Szilard visited Béla and Rose and her husband Roland (Lorand) Detre, in Switzerland in September 1937. After a rainstorm, he and his siblings spent an afternoon in an unsuccessful attempt to build a prototype collapsible umbrella. One reason for the visit was that he had decided to emigrate to the United States, as he believed that another war in Europe was inevitable and imminent. He reached New York on the liner RMS Franconia on January 2, 1938. Over the next few months he moved from place to place, conducting research with Maurice Goldhaber at the University of Illinois at Urbana–Champaign, and then the University of Chicago, University of Michigan and the University of Rochester, where he undertook experiments with indium but again failed to initiate a chain reaction.
In November 1938, Szilard moved to New York City, taking a room at the King's Crown Hotel near Columbia University. He encountered John R. Dunning, who invited him to speak about his research at an afternoon seminar in January 1939. That month, Niels Bohr brought news to New York of the discovery of nuclear fission in Germany by Otto Hahn and Fritz Strassmann, and its theoretical explanation by Lise Meitner, and Otto Frisch. When Szilard found out about it on a visit to Wigner at Princeton University, he immediately realized that uranium might be the element capable of sustaining a chain reaction.
Unable to convince Fermi that this was the case, Szilard set out on his own. He obtained permission from the head of the Physics Department at Columbia, George B. Pegram, to use a laboratory for three months. To fund his experiment, he borrowed $2,000 from a fellow inventor, Benjamin Liebowitz. He wired Frederick Lindemann at Oxford and asked him to send a beryllium cylinder. He convinced Walter Zinn to become his collaborator, and hired Semyon Krewer to investigate processes for manufacturing pure uranium and graphite.
Szilard and Zinn conducted a simple experiment on the seventh floor of Pupin Hall at Columbia, using a radium–beryllium source to bombard uranium with neutrons. Initially nothing registered on the oscilloscope, but then Zinn realized that it was not plugged in. On doing so, they discovered significant neutron multiplication in natural uranium, proving that a chain reaction might be possible. Szilard later described the event: "We turned the switch and saw the flashes. We watched them for a little while and then we switched everything off and went home." He understood the implications and consequences of this discovery, though. "That night, there was very little doubt in my mind that the world was headed for grief".
While they had demonstrated that the fission of uranium produced more neutrons than it consumed, this was still not a chain reaction. Szilard persuaded Fermi and Herbert L. Anderson to try a larger experiment using 500 pounds (230 kg) of uranium. To maximize the chance of fission, they needed a neutron moderator to slow the neutrons down. Hydrogen was a known moderator, so they used water. The results were disappointing. It became apparent that hydrogen slowed neutrons down, but also absorbed them, leaving fewer for the chain reaction. Szilard then suggested Fermi use carbon, in the form of graphite. He felt he would need about 50 tonnes (49 long tons; 55 short tons) of graphite and 5 tonnes (4.9 long tons; 5.5 short tons) of uranium. As a back-up plan, Szilard also considered where he might find a few tons of heavy water; deuterium would not absorb neutrons like ordinary hydrogen, but would have the similar value as a moderator. Such quantities of materiel would require a lot of money.
Szilard drafted a confidential letter to the President, Franklin D. Roosevelt, explaining the possibility of nuclear weapons, warning of the German nuclear weapon project, and encouraging the development of a program that could result in their creation. With the help of Wigner and Edward Teller, he approached his old friend and collaborator Einstein in August 1939, and convinced him to sign the letter, lending his fame to the proposal. The Einstein–Szilárd letter resulted in the establishment of research into nuclear fission by the U.S. government, and ultimately to the creation of the Manhattan Project. Roosevelt gave the letter to his aide, Brigadier General Edwin M. "Pa" Watson with the instruction: "Pa, this requires action!"
An Advisory Committee on Uranium was formed under Lyman J. Briggs, a scientist and the director of the National Bureau of Standards. Its first meeting on October 21, 1939, was attended by Szilard, Teller, and Wigner, who persuaded the Army and Navy to provide $6,000 for Szilard to purchase supplies for experiments—in particular, more graphite. A 1940 Army intelligence report on Fermi and Szilard, prepared when the United States had not yet entered World War II, expressed reservations about both. While it contained some errors of fact about Szilard, it correctly noted his dire prediction that Germany would win the war.
Fermi and Szilard met with representatives of National Carbon Company, who manufactured graphite, and Szilard made another important discovery. He asked about impurities in graphite, and learned that it usually contained boron, a neutron absorber. He then had special boron-free graphite produced. Had he not done so, they might have concluded, as the German nuclear researchers did, that graphite was unsuitable for use as a neutron moderator. Like the German researchers, Fermi and Szilard still believed that enormous quantities of uranium would be required for an atomic bomb, and therefore concentrated on producing a controlled chain reaction. Fermi determined that a fissioning uranium atom produced 1.73 neutrons on average. It was enough, but a careful design was called for to minimize losses. Szilard worked up various designs for a nuclear reactor. "If the uranium project could have been run on ideas alone," Wigner later remarked, "no one but Leo Szilard would have been needed."
The December 6, 1941, meeting of the National Defense Research Committee resolved to proceed with an all-out effort to produce atomic bombs, a decision given urgency by the Japanese attack on Pearl Harbor the following day that brought the United States into World War II, and then formal approval by Roosevelt in January 1942. Arthur H. Compton from the University of Chicago was appointed head of research and development. Against Szilard's wishes, Compton concentrated all the groups working on reactors and plutonium at the Metallurgical Laboratory of the University of Chicago. Compton laid out an ambitious plan to achieve a chain reaction by January 1943, start manufacturing plutonium in nuclear reactors by January 1944, and produce an atomic bomb by January 1945.
In January 1942, Szilard joined the Metallurgical Laboratory in Chicago as a research associate, and later the chief physicist. Alvin Weinberg noted that Szilard served as the project "gadfly", asking all the embarrassing questions. Szilard provided important insights. While uranium-238 did not fission readily with slow, moderated neutrons, it might still fission with the fast neutrons produced by fission. This effect was small but crucial. Szilard made suggestions that improved the uranium canning process, and worked with David Gurinsky and Ed Creutz on a method for recovering uranium from its salts.
A vexing question at the time was how a production reactor should be cooled. Taking a conservative view that every possible neutron must be preserved, the majority opinion initially favored cooling with helium, which would absorb very few neutrons. Szilard argued that if this was a concern, then liquid bismuth would be a better choice. He supervised experiments with it, but the practical difficulties turned out to be too great. In the end, Wigner's plan to use ordinary water as a coolant won out. When the coolant issue became too heated, Compton and the director of the Manhattan Project, Brigadier General Leslie R. Groves, Jr., moved to dismiss Szilard, who was still a German citizen, but the Secretary of War, Henry L. Stimson, refused to do so. Szilard was therefore present on December 2, 1942, when the first man-made self-sustaining nuclear chain reaction was achieved in the first nuclear reactor under viewing stands of Stagg Field, and shook Fermi's hand.
Szilard became a naturalized citizen of the United States in March 1943. The Army offered Szilard $25,000 for his inventions before November 1940, when he officially joined the project. He refused. He was the co-holder, with Fermi, of the patent on the nuclear reactor. In the end he sold his patent to the government for reimbursement of his expenses, some $15,416, plus the standard $1 fee. He continued to work with Fermi and Wigner on nuclear reactor design, and is credited with coining the term "breeder reactor".
With an enduring passion for the preservation of human life and political freedom, Szilard hoped that the U.S. government would not use nuclear weapons, but that the mere threat of such weapons would force Germany and Japan to surrender. He also worried about the long-term implications of nuclear weapons, predicting that their use by the United States would start a nuclear arms race with Russia. He drafted the Szilard petition advocating demonstration of the atomic bomb. The Interim Committee instead chose to use atomic bombs against cities over the protests of Szilard and other scientists. Afterwards, he lobbied for amendments to the Atomic Energy Act of 1946 that placed nuclear energy under civilian control.
In 1946, Szilard secured a research professorship at the University of Chicago that allowed him to research in biology and the social sciences. He teamed up with Aaron Novick, a chemist who had worked at the Metallurgical Laboratory during the war. The two men saw biology as a field that had not been explored as much as physics, and was ready for scientific breakthroughs. It was a field that Szilard had been working on in 1933 before he had become subsumed in the quest for a nuclear chain reaction. The duo made considerable advances. They invented the chemostat, a device for regulating the growth rate of the microorganisms in a bioreactor, and developed methods for measuring the growth rate of bacteria. They discovered feedback inhibition, an important factor in processes such as growth and metabolism. Szilard gave essential advice to Theodore Puck and Philip I. Marcus for their first cloning of a human cell in 1955.
Before relation with his later wife Gertrud Weiss, Leo Szilard's life partner in the period 1927 – 1934 was kindergarten teacher and opera singer Gerda Philipsborn, who also worked as a volunteer in a Berlin asylum organization for refugee children and in 1932 moved to India to continue in this work. Szilard married Gertrud (Trude) Weiss, a physician, in a civil ceremony in New York on October 13, 1951. They had known each other since 1929, and had frequently corresponded and visited each other ever since. Weiss took up a teaching position at the University of Colorado in April 1950, and Szilard began staying with her in Denver for weeks at a time when they had never been together for more than a few days before. Single people living together was frowned upon in the conservative United States at the time, and after they were discovered by one of her students, Szilard began to worry that she might lose her job. Their relationship remained a long-distance one, and they kept news of their marriage quiet. Many of his friends were shocked when they found out, as it was widely believed that Szilard was a born bachelor.
In 1949 Szilard wrote a short story titled "My Trial as a War Criminal" in which he imagined himself on trial for crimes against humanity after the United States lost a war with the Soviet Union. He publicly sounded the alarm against the possible development of salted thermonuclear bombs, explaining in radio talk on February 26, 1950, that sufficiently big thermonuclear bomb rigged with specific but common materials, might annihilate mankind. While Time magazine compared him to Chicken Little, and the Atomic Energy Commission dismissed the idea, scientists debated whether it was feasible or not. The Bulletin of the Atomic Scientists commissioned a study by James R. Arnold that concluded that it was.
Szilard published a book of short stories, The Voice of the Dolphins (1961), in which he dealt with the moral and ethical issues raised by the Cold War and his own role in the development of atomic weapons. The title story described an international biology research laboratory in Central Europe. This became reality after a meeting in 1962 with Victor F. Weisskopf, James Watson and John Kendrew. When the European Molecular Biology Laboratory was established, the library was named The Szilard Library and the library stamp features dolphins. Other honors that he received included the Atoms for Peace Award in 1959, and the Humanist of the Year in 1960. A lunar crater on the far side of the Moon was named after him in 1970. The Leo Szilard Lectureship Award, established in 1974, is given in his honor by the American Physical Society.
In 1960, Szilard was diagnosed with bladder cancer. He underwent cobalt therapy at New York's Memorial Sloan-Kettering Hospital using a cobalt 60 treatment regimen that he designed himself. A second round of treatment with an increased dose followed in 1962. The doctors tried to tell him that the increased radiation dose would kill him, but he said it wouldn't, and that anyway he would die without it. The higher dose did its job and his cancer never returned. This treatment became standard for many cancers and is still used.
Szilard spent his last years as a fellow of the Salk Institute for Biological Studies in La Jolla, California, which he had helped to create. He was appointed a non-resident fellow there in July 1963, and became a resident fellow on April 1, 1964, after moving to La Jolla in February. With Trude, he lived in a bungalow on the property of the Hotel del Charro. On May 30, 1964, he died there in his sleep of a heart attack; when Trude awoke, she was unable to revive him. His remains were cremated.
His papers are in the library at the University of California in San Diego. In February 2014, the library announced that they received funding from the National Historical Publications and Records Commission to digitize its collection of his papers, extending from 1938 to 1998.
The Atoms for Peace Award was established in 1955 through a grant of $1,000,000 by the Ford Motor Company Fund. An independent nonprofit corporation was set up to administer the award for the development or application of peaceful nuclear technology. It was created in response to U.S. President Dwight D. Eisenhower's Atoms for Peace speech to the United Nations.
The 23 recipients were:
1957 - Niels Bohr
1958 - George C. de Hevesy
1959 - Leó Szilárd and Eugene Paul Wigner
1960 - Alvin M. Weinberg and Walter Henry Zinn
1961 - Sir John Cockcroft
1963 - Edwin M. McMillan and Vladimir I. Veksler
1967 - Isidor I. Rabi, W. Bennett Lewis and Bertrand Goldschmidt
1968 - Sigvard Eklund, Abdus Salam, and Henry DeWolf Smyth
1969 - Aage Bohr, Ben R. Mottelson, Floyd L. Culler, Jr., Henry S. Kaplan, Anthony L. Turkevich, M. S. Ioffe and Compton A. Rennie
1969 - Dwight D. EisenhowerCouncil for a Livable World
Council for a Livable World is a Washington, D.C.-based non-profit, advocacy organization dedicated to eliminating the U.S. arsenal of nuclear weapons. Its stated aim is for "progressive national security policies and helping elect congressional candidates who support them." The Council was founded in 1962 as the Council for Abolishing War by Hungarian nuclear physicist Leó Szilárd. Its research arm, the Center for Arms Control and Non-Proliferation, provides research to members of Congress and their staff. In February, 2016, John F. Tierney was appointed the executive director of the Council for a Livable World and the Center for Arms Control and Non-Proliferation, the council’s affiliated education and research organization. For more than 50 years, the Council for a Livable World has been advocating for a more principled approach to U.S. national security and foreign policy.Day One (1989 film)
Day One is a made-for-TV documentary-drama movie about The Manhattan Project, the research and development of the atomic bomb during World War II. It is based on the book by Peter Wyden. The movie was written by David W. Rintels and directed by Joseph Sargent. It starred Brian Dennehy as General Leslie Groves, David Strathairn as Dr. J. Robert Oppenheimer and Michael Tucker as Dr. Leo Szilard. It premiered in the United States on March 5, 1989 on the CBS network. It won the 1989 Emmy award for Outstanding Drama/Comedy Special. The movie received critical acclaim for its historical accuracy despite being a drama.Einstein refrigerator
The Einstein–Szilard or Einstein refrigerator is an absorption refrigerator which has no moving parts, operates at constant pressure, and requires only a heat source to operate. It was jointly invented in 1926 by Albert Einstein and his former student Leó Szilárd, who patented it in the U.S. on November 11, 1930 (U.S. Patent 1,781,541).
This is an alternative design from the original invention of 1922 by the Swedish inventors Baltzar von Platen and Carl Munters.Einstein–Szilárd letter
The Einstein–Szilárd letter was a letter written by Leó Szilárd and signed by Albert Einstein that was sent to the United States President Franklin D. Roosevelt on August 2, 1939. Written by Szilárd in consultation with fellow Hungarian physicists Edward Teller and Eugene Wigner, the letter warned that Germany might develop atomic bombs and suggested that the United States should start its own nuclear program. It prompted action by Roosevelt, which eventually resulted in the Manhattan Project developing the first atomic bombs.Emergency Committee of Atomic Scientists
The Emergency Committee of Atomic Scientists (ECAS) was founded by Albert Einstein and Leó Szilárd in 1946. Its aims were to warn the public of the dangers associated with the development of nuclear weapons, promote the peaceful use of nuclear energy, and ultimately work towards world peace, which was seen as the only way that nuclear weapons would not be used again.
The Committee was established in the wake of the "Szilárd petition" (July 1945) to United States president Harry S. Truman opposing the use of the atomic bomb on moral grounds, which was signed by 68 scientists who had worked on the Manhattan Project. A majority of scientists working on the Manhattan Project did not know entirely what they were creating at the time.
The Committee only ever consisted of the eight members of the Board of Trustees, who were:
Albert Einstein Chairman
Harold C. Urey Vice-Chairman
Philip M. Morse
Victor WeisskopfHalf the members had worked directly on the Manhattan Project and all had been indirectly involved or consulted on the production of the first atomic bomb.
Several members of the committee gave lecture tours to promote the committee's message of peace.
They produced supporting promotional materials, including one of the first films to illustrate what a full nuclear war might be like. ECAS was also very vocal in its opposition of the development of the first hydrogen bomb.
ECAS was active for four years, until 1950 when it was gradually disbanded, although most of the members continued to campaign against nuclear war, and participated in the Pugwash Conferences on Science and World Affairs.Eugene Rabinowitch
Eugene Rabinowitch (1901–1973) was a Russian-born American biophysicist who is best known for his work in relation to nuclear weapons, especially as a co-author of the Franck Report and a co-founder in 1945 of the Bulletin of the Atomic Scientists, a global security and public policy magazine, which he edited until his death.When Rabinowitch arrived in New York City, he was assisted by Selig Hecht,
a man whose spontaneous sympathy, friendship and assistance were so generously given to me when I first came to America and felt lost in the human sea of New York.During World War II, Rabinowitch worked in the Metallurgical Laboratory (or "Met Lab"), the Manhattan Project's division at the University of Chicago. At that time he was a member of the Committee on Political and Social Problems, chaired by James Franck. Rabinowitch wrote (with help from Leó Szilárd) what became known as the Franck Report. The report recommended that nuclear energy be brought under civilian rather than military control and argued that the United States should demonstrate the atomic bomb to world leaders in an uninhabited desert or barren island before using it in combat.
The social and ethical concerns expressed in the Franck Report translated into the guiding principles of the Bulletin of the Atomic Scientists, founded by Rabinowitch and fellow physicist Hyman Goldsmith. In the twenty-fifth anniversary issue of the Bulletin, Rabinowitch wrote that the magazine's purpose "was to awaken the public to full understanding of the horrendous reality of nuclear weapons and of their far-reaching implications for the future of mankind; to warn of the inevitability of other nations acquiring nuclear weapons within a few years, and of the futility of relying on America's possession of the 'secret' of the bomb." Over the years, Rabinowitch wrote more than 100 articles for the magazine, most of them editorials.
Before the war, Rabinowitch passionately pursued research in photosynthesis, a field in which he was to become a leader. After World War II, Rabinowitch taught and researched botany as a professor at the University of Illinois at Urbana-Champaign, continuing his photosynthesis work and publishing the three-volume Photosynthesis and Related Processes, as well as many other books.
A bibliography of Rabinowitch's publications was compiled by Govindjee at the Department of Botany, University of Illinois. The papers of Rabinowitch are held in the Special Collections at the University of Chicago Library.James L. Tuck
James Leslie Tuck OBE, (9 January 1910 – 15 December 1980) was a British physicist. He was born in Manchester, England, and educated at the Victoria University of Manchester. Because of his involvement with the Manhattan Project, he was unable to submit his thesis on time and never received his doctoral degree.
In 1937 he was offered an appointment as a Salter Research Fellow at Oxford University, where he worked with Leó Szilárd on particle accelerators.
At the outbreak of World War II, he was appointed as the scientific advisor to Frederick Alexander Lindemann, who was on the private staff of Winston Churchill. His research included work on shaped charges, used in anti-tank weapons. For this work he received the Order of the British Empire from King George VI.Leo Szilard Lectureship Award
The Leo Szilard Lectureship Award (originally called the Leo Szilard Award) is given annually by the American Physical Society (APS) for "outstanding accomplishments by physicists in promoting the use of physics for the benefit of society". It is given internationally in commemoration of physicist Leo Szilard.
"In the year's of Szilard's life and activity it became clearer than ever before how great the responsibility of scientists is to the society. And, to a large extent, it is due to Szilard that this awareness began to spread in the scientific community." - Andrei Sakharov
It is often awarded to physicists early in their careers who are active in areas such as environmental issues, arms control, or science policy. As of 2015 the recipient is given $3,000 plus $2,000 travel expenses and is expected to lecture at an APS meeting and at educational or research laboratories, to promote awareness of their activities.Leószilárdite
Leószilárdite is a mineral discovered by Travis Olds of the University of Notre Dame and colleagues in the Markey Mine in Utah, USA. They named the mineral in honor of Leó Szilárd, Hungarian-born physicist and inventor. Leószilárdite is the first naturally occurring sodium- and magnesium-containing uranyl carbonate. It is rare and water-soluble, and was discovered on a seam of carbon-rich material deposited by an ancient stream. Groundwater reacted with the uraninite ore to create leószilárdite and other minerals.M. V. Ramana
M. V. Ramana is a physicist who works at the Nuclear Futures Laboratory and the Program on Science and Global Security, both at Princeton University, on the future of nuclear power in the context of climate change and nuclear disarmament. Ramana is a member of the International Panel on Fissile Materials and the Bulletin of the Atomic Scientists’ Science and Security Board.Ramana has written many papers and is the author of The Power of Promise: Examining Nuclear Energy in India (Penguin Books, 2012). He is co-editor of Prisoners of the Nuclear Dream (New Delhi: Orient Longman, 2003) and author of Bombing Bombay? Effects of Nuclear Weapons and a Case Study of a Hypothetical Explosion (Cambridge, MA: International Physicians for the Prevention of Nuclear War, 1999).M. V. Ramana obtained his Ph.D. in Physics from Boston University in 1994 and was a post-doctoral fellow at the Department of Physics, University of Toronto and the Center for International Studies, Massachusetts Institute of Technology. In 2014, Ramana received the Leo Szilard Award of the American Physical Society.Salted bomb
A salted bomb is a nuclear weapon designed to function as a radiological weapon, producing enhanced quantities of radioactive fallout, rendering a large area uninhabitable. The term is derived both from the means of their manufacture, which involves the incorporation of additional elements to a standard atomic weapon, and from the expression "to salt the earth", meaning to render an area uninhabitable for generations. The idea originated with Hungarian-American physicist Leo Szilard, in February 1950. His intent was not to propose that such a weapon be built, but to show that nuclear weapon technology would soon reach the point where it could end human life on Earth. No intentionally salted bomb has ever been atmospherically tested, and as far as is publicly known, none have ever been built. However, the UK tested a 1 kiloton bomb incorporating a small amount of cobalt as an experimental radiochemical tracer at their Tadje testing site in Maralinga range, Australia, on September 14, 1957. The triple "taiga" nuclear salvo test, as part of the preliminary March 1971 Pechora–Kama Canal project, produced substantial amounts of Co-60, with this fusion generated neutron activation product being responsible for about half of the gamma dose now (2011) at the test site.A salted bomb should not be confused with a dirty bomb, which is an ordinary explosive bomb containing radioactive material which is spread over the area when the bomb explodes. A salted bomb is able to contaminate a much larger area than a dirty bomb.Spencer R. Weart
Spencer R. Weart (born 1942) was the director of the Center for History of Physics of the American Institute of Physics (AIP) from 1971 until his retirement in 2009.Spitz (surname)
Spitz is a German surname. Notable people with the surname include:
Armand Spitz (1904–1971), American planetarium designer
Bob Spitz, American journalist and author
Carl Spitz (1894–1976), Hollywood dog trainer
Chantal Spitz (born 1954), French Polynesian writer
Dan Spitz (born 1963), American guitarist
Dave Spitz (born 1955), American bassist
Donald Spitz, American anti-abortion activist
Elisa Spitz, American figure skater
Fannie S. Spitz (1873–1943), American inventor
Gerald J. Spitz, American politician
Hanneliese Spitz (born 1941), Austrian sprint canoeist
Herman H. Spitz, American psychologist
Jacques Spitz (1896–1963), French writer
Jason Spitz (born 1982), American football player
Leó Szilárd, born Leó Spitz, Hungarian scientist
Lewis Spitz (born 1939), South African paediatric surgeon
Malte Spitz (born 1984), German politician
Marc Spitz (1969–2017), American writer and music journalist
Mark Spitz (born 1950), American swimmer
René Spitz (1887–1974), Austrian-American psychoanalyst
Sabine Spitz (born 1971), German cross-country cyclist
Sophie Spitz (1910–1956), American pathologist
Tibor Spitz, American artist and Holocaust survivor
Vivien Spitz, American journalistSzilard (crater)
Szilard is a damaged lunar impact crater that lies to the east-northeast of the crater Richardson. It is named after Leó Szilárd, the scientist who theorised nuclear chain reactions and famously worked on the atomic bomb during World War II. About a half-crater-diameter to the northwest is the large walled plain Harkhebi. Between Harkhebi and Szilard is the small Giordano Bruno. The ray system from this impact forms streaks across the rim and interior of Szilard.
The rim of Szilard is heavily eroded and has been reshaped by subsequent impacts. The worn satellite crater Szilard H lies across the southeast rim of Szilard. The interior floor of Szilard is somewhat uneven in the western half, while the eastern side is more level and featureless.
Szilard lies on the far side of the Moon and cannot be seen directly from the Earth.
Prior to formal naming in 1970 by the IAU, this crater was known as Crater 116.Szilárd petition
The Szilárd petition, drafted by scientist Leo Szilard, was signed by 70 scientists working on the Manhattan Project in Oak Ridge, Tennessee, and the Metallurgical Laboratory in Chicago, Illinois. It was circulated in July 1945 and asked President Harry S. Truman to inform Japan of the terms of surrender demanded by the allies, and allow Japan to either accept or refuse these terms, before America used atomic weapons. However, the petition never made it through the chain of command to President Truman. It also was not declassified and made public until 1961.
Later, in 1946, Szilard jointly with Albert Einstein, created the Emergency Committee of Atomic Scientists that counted among its board, Linus Pauling (Nobel Peace Prize in 1962).The Martians (scientists)
"The Martians" was a term used to refer to a group of prominent Hungarian scientists (mostly, but not exclusively, physicists and mathematicians) who emigrated to the United States in the early half of the 20th century. Leó Szilárd, who jokingly suggested that Hungary was a front for aliens from Mars, used this term. In an answer to the question of why there is no evidence of intelligent life beyond earth despite the high probability of it existing, Szilárd responded: "They are already here among us – they just call themselves Hungarians." This account is featured in György Marx's book The Martians.
Paul Erdős, Paul Halmos, Theodore von Kármán, John G. Kemeny, John von Neumann, George Pólya, Leó Szilárd, Edward Teller, and Eugene Wigner are included in this group. Dennis Gabor (Gábor Dénes), Ervin Bauer, Róbert Bárány, George de Hevesy (Hevesy György Károly), Nicholas Kurti (Kürti Miklós), George Klein, Eva Klein, Michael Polanyi (Polányi Mihály) and Marcel Riesz are also sometimes named, though they did not emigrate to the United States.
Loránd Eötvös, Kálmán Tihanyi, Zoltán Lajos Bay, Victor Szebehely, Albert Szent-Györgyi, Georg von Békésy and Maria Telkes are often mentioned in connection.
Elizabeth Róna was a Hungarian nuclear chemist who emigrated to the United States in 1941 to work on the Manhattan Project and discovered Uranium-Y is not often included.William R. Kanne
William R. Kanne worked on Chicago Pile One along with Enrico Fermi and Leó Szilárd. He invented the Kanne Chamber (patent no. 2,599,922), a way of monitoring gas for radioactivity. The patent was filed on 12 October 1944.Wolfgang K. H. Panofsky
Wolfgang Kurt Hermann "Pief" Panofsky (April 24, 1919 – September 24, 2007), was a German-American physicist who won many awards including the National Medal of Science.