Background

Leo Szilard was born on February 11, 1898, in Budapest, Kingdom of Hungary (present-day Budapest, Hungary) into a family of middle-class Jewish parents — Louis Spitz, a civil engineer and architect, and Thekla (Vidor) Szilard. Leo had a brother, named Béla, and a sister, named Rózsi (Rose).

On October 4, 1900, the family changed its surname from the German "Spitz" to the Hungarian "Szilárd", a name, that means "solid" in Hungarian.

Education

Leo was a sickly child, and for a number of years, his mother taught him at home. During the period from 1908 to 1916, he attended Reáliskola high school in his home town.

In the fall of 1916, Szilard entered the Budapest Institute of Technology (present-day Budapest University of Technology and Economics), intending to major in electrical engineering. At the end of his first year at the institute, in 1917, he was called to service in the Austro-Hungarian army and assigned to officer training school. Leo became very ill with influenza, and was returned home for hospitalization. Later, Leo was informed, that his regiment had been nearly annihilated in battle, so the illness probably saved his life. In November 1918, after the Armistice, Szilard was honorably discharged.

The same year, in 1918, he returned to the Budapest Institute of Technology for just a year before transferring to the Technische Hochschule at Berlin-Charlottenburg (present-day Technical University of Berlin) in 1919.

In Berlin, Szilard’s career outlook underwent a significant change. He came into contact with some of the finest physicists in the world, including Albert Einstein, Max Planck and Max von Laue, the last of whom was to become Szilard’s own doctoral advisor. Szilard decided, that his real interests lay in the field of physics, rather than engineering, and in 1922, he received a Doctor of Philosophy degree in that field from the present-day Technical University of Berlin.

Leo's doctoral thesis, written under the supervision of von Laue, dealt with the statistical implications of the second law of thermodynamics. His work on this topic continued for a number of years, culminating in a paper, published in 1929, "On the Decrease of Entropy in a Thermodynamic System by the Intervention of Intelligent Beings", in which he investigated the application of thermodynamical laws to information theory. That paper is regarded as an important precursor to modern cybernetic theories.

Career

In 1922, Szilard was appointed a research assistant at the Institute for Theoretical Physics, University of Berlin, a post he held till 1925, when he was made a Privatdozent (private lecturer) in physics at the same institut, the director of which at the time was Max von Laue, his former advisor. In addition to his continuing work on thermodynamics during that period, Szilard also originated a series of studies on X-ray crystallography, a field, in which von Laue was a world leader. Szilard also worked closely with Albert Einstein on the development of a pump for liquid metals, for which he eventually obtained a patent. In addition, he became interested in the problem of particle accelerators and invented a number of devices, that were later to be incorporated into early cyclotrons.

In 1933, the rise of Adolf Hitler convinced Szilard, who was Jewish, that he should leave Germany. Fearing for both his career and his life, he fled first to Vienna and then, six weeks later, to England. The same year, in 1933, he joined the physics department at St. Bartholomew’s Hospital in London. In 1935, he moved to the Clarendon Laboratory in Oxford, where Leo worked as a researcher until 1938.

It was during the period in Oxford, that Szilard received news of Frederic and Irene Joliot-Curie’s discovery of artificial radioactivity. He began to think about the possibility of a nuclear chain reaction, in which the nuclear decay of one atom, brought about by some type of particle, would result in the production of a new atom with the release of more particles of the kind, needed to start the reaction. In such a case, the reaction, once initiated, would be self-sustaining over many, many episodes of decay. The value of such a reaction, Szilard knew, was that energy would be released in each step of the process. After countless repetitions of the reaction, huge amounts of energy — sufficient, for instance, to make a powerful bomb — would be released.

Szilard first explored the possibility of using beryllium in such a chain reaction. He and a colleague, T. A. Chalmers, found, that gamma rays, directed at a beryllium target, would cause the emission of a neutron from the beryllium nucleus. The two hoped, that this reaction could act as the first step in a chain reaction, in which beryllium atoms would break apart to form helium atoms and more neutrons. The neutrons, thus formed, would, they hoped, cause more beryllium atoms to break apart into helium atoms with the release of more neutrons, and so on. More detailed studies showed, however, that such a reaction could not be sustained.

At that time, in addition to his research, Szilard continued his efforts to find new jobs for scientists, fleeing the Nazi purges on the continent. These efforts were characteristic of Szilard’s life-long commitment to helping others. He once said, that this humanitarian impulse was largely the result of reading, at the age of ten, Hungarian author Imre Madach’s "The Tragedy of Man".

Toward the end of 1938, Szilard decided to move to the United States. In 1938, he was appointed a researcher at Columbia University. During his stint at the university, he received startling news from Europe, that Otto Hahn and Fritz Strassman had produced the first fission of an atomic nucleus, an event, that was fully understood and explained by Lise Meitner in January, 1939. Szilard immediately recognized the significance of this discovery. It held the potential for making possible the very kind of nuclear chain reaction, on which he had been working in London.

With a colleague, Walter Zinn, Szilard set up a replica of the Hahn-Strassman experiment at Columbia University. Their goal was to find out whether the fission of the uranium nucleus would result in the formation of at least one neutron, a condition, necessary for the maintenance of a chain reaction. On March 3, the experiment was ready. A few flashes of light on an oscilloscope gave Szilard and Zinn the answer they sought: neutrons were being released during the fission of uranium. A nuclear chain reaction was possible. Szilard would later say he knew immediately, that this discovery would cause the world great sorrow.

News of the discovery of nuclear fission swept through the physics community like wildfire. Few failed to grasp the military potential of the discovery. A group of physicists in the United States, who were particularly concerned about this potential, became convinced, that the United States government must take fast and aggressive action to see whether nuclear fission could really be used in the development of weapons. Szilard composed a letter, which Albert Einstein signed, presenting their arguments to President Franklin D. Roosevelt. Roosevelt responded by appointing an Advisory Committee on Uranium to investigate the issue. After some initial hesitation, the committee produced a favorable recommendation, and the Manhattan Engineering District Project was created to pursue the development of the world’s first atomic bombs. The first contract, let under the Manhattan Project, was to a group of scientists at Columbia, that included Szilard.

In 1942, Leo left Columbia University to become a part of the Manhattan Project’s Metallurgical Laboratory at the University of Chicago. Working there with Enrico Fermi, he witnessed the first controlled nuclear reaction on December 2, 1942, when the world’s first atomic pile (nuclear reactor) was put into operation. The hopes and dreams, as well as the fears, that Szilard had long held for nuclear chain reactions, became a reality.

Shortly thereafter, Szilard began to argue for a cessation of research on nuclear weapons. A number of factors influenced his position. First, he was convinced, that the tide of war had turned in favor of the Allies, and he thought the war could soon be ended with conventional weapons. Second, he feared, that the successful development of nuclear weapons would lead to an all-out arms race with the Soviet Union after the war. Finally, he recognized the horrible human tragedies, that would result from the use of an atomic bomb. His suggestions for a demonstration test of nuclear weapons in an uninhabited area, to which the Japanese government would be invited, fell on deaf ears, however. Instead, on August 6 and 9, 1945, the first atomic bombs were dropped on Hiroshima and Nagasaki in Japan. The war ended a week later.

In the post-war years, Szilard spent a major portion of his time, working for the control of the "demon" he had helped release — atomic energy. He joined a large number of his fellow nuclear scientists in forming the Federation of Atomic Scientists, which worked to keep control of atomic energy out of the hands of the military and within a civilian department. He also made efforts to encourage mutual disarmament and the reduction of tensions between the United States and the Soviet Union. To this end, he was active in the formation and planning of the Pugwash Conferences on Science and World Affairs, a series of conferences on nuclear safety, that met in the late 1950's and early 1960's. In 1962, Leo helped to found the Council for a Livable World, a Washington, D.C.-based lobby for nuclear arms control, in which he sought the cooperation between American and Soviet scientists and politicians.

In the late 1940's, Szilard once again turned to scientific research, but this time in the field of biology. In 1946, he accepted an appointment as a professor of biophysics at the University of Chicago. One of his first accomplishments was the development of the chemostat, an instrument, that aids in the study of bacteria and viruses by making it possible to regulate various growth factors. Also, Szilard took part in the first cloning of a human cell.

Later, Leo became interested in the biology of aging. Another topic, in which Szilard became interested, namely memory and recall, was the subject of his final scientific paper, published after his death.

In his last years, Leo helped to found Salk Institute for Biological Studies in La Jolla, California. 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.

Achievements

• Leo Szilard was known as a physicist, who helped to conduct the first sustained nuclear chain reaction and was instrumental in initiating the Manhattan Project for the development of the atomic bomb. He was the first to patent the idea of a nuclear reactor, working together with Enrico Fermi. In addition to the nuclear reactor, Szilard submitted patent applications for a linear accelerator in 1928, and a cyclotron in 1929.
  
  Also, Leo worked with Albert Einstein on the development of the famous Einstein refrigerator and conceived the first idea of an electron microscope. Moreover, Szilard was the first to recognize the connection between thermodynamics and information theory.
  
  In biology, he invented the chemostat, discovered feedback inhibition and was involved in the first cloning of a human cell.
  
  His other important achievements include a cobalt bomb; an absorption refrigerator and others.
  
  During his lifetime, Szilard also worked hard to stimulate mutual disarmament and the reduction of tensions between the United States and the Soviet Union.
  
  He received several awards, including Einstein Gold Medal in 1958, Atoms for Peace Award in 1959 and others. In 1960, Szilard was made an American Humanist Association's Humanist of the Year. Later, in 1970, a crater Szilard on the dark side of the Moon was named after him.

Works

More photos

• book

  • Toward a Livable World: Leo Szilard and the Crusade for Nuclear Arms Control

    (This book documents Szilard's energetic attempts to influ...)

    1987
  • The Voice of the Dolphins and Other Stories

    (This work represents a classic pulp fiction by one of the...)

    1961
  • Collected Works of Leo Szilard

    (Scientific papers.)

    1972
  • Leo Szilard: His Version of the Facts: Selected Recollections and Correspondence 1978

Religion

Despite having a religious background, Szilard was an agnostic.

Politics

During his early years, in the late 1910's - early 1920's, 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. Leo 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.

In his lifetime, Leo publicly stated his opposition to using the bomb in war, though he wanted to develop weapons before Nazi Germany. He attempted to avert the use of the bomb against Japan in a petition, meant to go to President Truman, though it never reached him. After World War II, Szilard continued his political activism, calling for international arms control, peaceful uses of nuclear energy and improved United States-Soviet relations. Also, he founded the Council for a Livable World, warning of the threat of nuclear war.

Views

Quotations: "A scientist's aim in a discussion with his colleagues is not to persuade, but to clarify."

"I'm all in favor of the democratic principle, that one idiot is as good as one genius, but I draw the line, when someone takes the next step and concludes, that two idiots are better, than one genius."

"If you want to succeed in the world, you don't have to be much cleverer, than other people. You just have to be one day earlier."

"Don't lie if you don't have to."

"If one knows only what one is told, one does not know enough to be able to arrive at a well-balanced decision."

"Do your work for six years; but in the seventh, go into solitude or among strangers, so that the memory of your friends does not hinder you from being what you have become."

"Pronouncement of experts to the effect, that something cannot be done, has always irritated me."

"We turned the switch, saw the flashes, watched for ten minutes, then switched everything off and went home. That night I knew the world was headed for sorrow."

Membership

Szilard was a member of the Federation of Atomic Scientists.

• 

  member

  National Academy of Sciences , United States

  1961

Personality

Leo was a true believer in science and its potential to save the world. Always a visionary, Szilard, sacrificing many years of his career and having no permanent post for himself, worked tirelessly to find suitable positions for many of the other scientists, fleeing Germany. Often working by himself, at the detriment of his own safety and career, Szilard was responsible for numerous colleagues being offered positions.

Quotes from others about the person

• As recalled by Bernard Feld, Szilard was "an indispensable factor in the successful achievement of the first man-made nuclear chain reaction and in the vast wartime enterprise, known as the Manhattan Project, which culminated in the first man-made nuclear explosion".
  
  On Szilard's influence, Edward Teller said: "He was the most stimulating of all the people I have known. In a world, in which conformity is almost a duty, Szilard remained a dedicated nonconformist". And further: "He (Szilard) played a unique role in American history. His ideas about atomic energy were ridiculed by Ernest Rutherford and doubted by Niels Bohr and Enrico Fermi, but accepted and acted upon by Albert Einstein and President Roosevelt".
  
  As noted by Teller: "Szilard was the originator of many ideas, ranging from information theory to the sexual life of bacteria, from how to release atomic energy to a proposal, that people, who inform about violations of disarmament treaties, ought to receive international awards".

Connections

On October 13, 1951, Leo married Gertrud (Trude) Weiss, whom he had first met in 1933 in Vienna, where Weiss was a medical student. The couple had no children.

Father:

Louis Spitz

Mother:

Thekla (Vidor) Szilard

Brother:

Béla Spitz

Sister:

Rózsi (Rose) Spitz

Wife:

Gertrud (Trude) Weiss

mentor:

Max von Laue

colleague:

Enrico Fermi

colleague:

Walter Zinn

colleague:

Albert Einstein

colleague:

Eugene Wigner

colleague:

Edward Teller

References

• Genius in the Shadows: A Biography of Leo Szilard, the Man Behind the Bomb This work represents a biography of Leo Szilard, known in scientific circles as "father of the atom bomb".
  1992
• The Making of the Atomic Bomb Reading like a character-driven suspense novel, the book introduces the players in the saga of physics, politics and human psychology, from Franklin D. Roosevelt and Einstein, to the visionary scientists, who pioneered quantum theory and the application of thermonuclear fission, including Planck, Szilard, Bohr, Oppenheimer, Fermi, Teller, Meitner, von Neumann and Lawrence.
  1986
• Leo Szilard: Science as a Mode of Being This intellectual biography of Szilard captures the visionary centerpoint of his passion for science and public activism. This work will be of interest to historians of science, physicists and biologists.
  1996