Leó Szilárd

Leó Szilárd (February 11, 1898 – May 30, 1964) was a Hungarian-American physicist who conceived the nuclear chain reaction and worked on the Manhattan Project. He was born in Budapest and died in La Jolla, California.

Personality

Szilárd was well known to his colleagues as an eccentric, lightning-quick thinker who "seemed fond of startling people" with strange, seemingly incongruous, yet extremely perceptive statements and questions. He was also extremely good at predicting political events. He is said to have predicted World War I as a boy, and when the Nazi party first appeared, he predicted that it would one day control Europe. In 1934, he foresaw the details of World War II. He then made a habit of residing in hotel rooms, with a packed suitcase always on hand. He often did a lot of his best thinking while taking a bath.

Early Life

Szilárd was born in Budapest at the time of the Austro-Hungarian monarchy before World War I as the son of a Jewish civil engineer. From 1908-1916 he attended Reáliskola in his home town. He was enrolled as an engineering student at Budapest Technical University in 1916 but had to join the Austro-Hungarian Army in 1917 as officer-candidate where he was honorably discharged at the end of the war. In 1919 he resumed engineering studies at Budapest Technical University but soon decided to leave Hungary because of the rising antisemitism under the Horthy regime which led to the introduction of a numerus clausus for Jewish students at Hungary's universities. He continued engineering studies at Technische Hochschule (Institute of Technology) in Berlin-Charlottenburg. He soon changed to physics there and took physics classes from Einstein, Planck, and von Laue. His dissertation on thermodynamics in 1922 was praised by Einstein and awarded the notation "eximia," the highest honor. In 1923 he received the doctorate in physics from the Humboldt University of Berlin. He was appointed as assistant to Max von Laue at the University of Berlin's Institute for Theoretical Physics in 1924. In 1927 he finished his habilitation and became a Privatdozent (instructor) in Physics at University of Berlin. During his time in Berlin he was working on numerous technical inventions (1928 German patent application on the linear accelerator, 1929 German patent application on the cyclotron, since 1926 work with Einstein on the construction of a refrigerator without moving parts (US patent number 1,781,541 on November 11, 1930)).

Developing the idea of the nuclear chain reaction

In 1933 Szilárd fled to London to escape Nazi persecution, where he read an article written by Ernest Rutherford in The Times which rejected the possibility of using atomic energy for practical purposes. Although nuclear fission had not yet been discovered, Szilárd was reportedly so annoyed at this dismissal that he conceived of the idea of the nuclear chain reaction while waiting for traffic lights to change on Southampton Row in Bloomsbury. The following year he filed for a patent on the concept.

Szilárd first attempted to create a chain reaction using beryllium and indium, but these elements did not produce a chain reaction. In 1936, he assigned the chain-reaction patent to the British Admiralty to ensure its secrecy (). Szilárd also was the co-holder, with Nobel Laureate Enrico Fermi, of the patent on the nuclear reactor ().

In 1938 Szilárd accepted an offer to conduct research at Columbia University in Manhattan, and moved to New York, and was soon joined by Fermi. After learning about nuclear fission in 1939, they concluded that uranium would be the element capable of sustaining a chain reaction.

The Manhattan Project

Szilárd was instrumental in the development of the Manhattan Project. It was his idea to send a confidential letter to Franklin D. Roosevelt explaining the possibility of nuclear weapons, and to encourage the development of a program which could lead to their creation. In August 1939 he obtained Albert Einstein's endorsement of this proposal, and the Einstein-Szilárd letter eventually led to the establishment of research into nuclear fission by the U.S. government. Later, he moved to the University of Chicago to continue work on the project. There, along with Fermi, he helped to construct the first "neutronic reactor", a uranium and graphite "atomic pile" in which the first self-sustaining nuclear chain reaction was achieved, in 1942.

As the war continued, Szilárd became increasingly dismayed that scientists were losing control over their research to the military, and clashed many times with General Leslie Groves, military head of the project. His resentment towards the U.S. government was exacerbated by his failed attempt to avoid the use of the atomic bomb in war.

Szilárd became a naturalized citizen of the United States in 1943.

Views on the use of nuclear weapons

In 1932 Szilárd had read about the fictional "atomic bombs" described in H. G. Wells's science fiction novel The World Set Free. This inspired him to be the first scientist to seriously examine the science behind the creation of nuclear weapons.

As a survivor of a devastated Hungary after World War I, and having witnessed the subsequent terror of the Reds and the Whites, Szilárd developed an enduring passion for the preservation of human life and freedom, especially freedom to communicate ideas.

He hoped that the U.S. government, which prior to World War II was staunchly opposed to the bombing of civilians, would not use nuclear weapons, because of their potential for use against civilian populations. Szilárd hoped that the mere threat of such weapons would force Germany and/or Japan to surrender. He drafted the Szilárd petition advocating demonstration of the atomic bomb. However, rather than threatening the Axis Powers, President Harry Truman sided with advisors who thought use of the weapons was the best solution, and chose to deploy the weapons over the protestations of Szilárd and many of the other top scientists in the project. (See also: Atomic bombings of Hiroshima and Nagasaki)

The atomic bombings of Japan resulted in the deaths of as many as 250,000 people, the total destruction of Hiroshima, the partial destruction of Nagasaki, and led within the week to the unconditional surrender of Imperial Japan. However, the use of the atomic bomb was considered by some to be humane in the sense that it halted the mass slaughter which had characterized modern industrial warfare. To wit, the firebombing of Dresden, Hamburg and Tokyo caused more deaths than even Hiroshima and Nagasaki. On the other hand, author James Carroll in his book The House of War maintains the obstacle in ending the war was the insistence on unconditional surrender. He writes that Japan was ready to surrender in July, 1945, on the condition that it could keep its Emperor, a condition that was later accepted. He writes the true purpose of the nuclear bombing was to intimidate Stalin.

Before the war, Szilárd had considered the U.S. the one truly humane government in the world; that is why he chose to assist the U.S. with the atomic bomb. He abandoned this view after the weapons use.

After the war

In 1947, Szilárd switched fields of study because of his horror of atomic weapons, moving from physics to molecular biology, working extensively with Aaron Novick. He proposed, in February of 1950, a new kind of nuclear weapon using cobalt as a tamper, a cobalt bomb, which he said might wipe out all life on the planet. U.S. News & World Report featured an interview with Szilárd in its August 15, 1960 issue, "President Truman Didn't Understand." His penchant to use language provocatively and say things which most readers would dismiss as absurd is well evidenced in this quote from that interview, "But again, I don't believe this staging a demonstration was the real issue, and in a sense it is just as immoral to force a sudden ending of a war by threatening violence as by using violence. My point is that violence would not have been necessary if we had been willing to negotiate." He spent his last years as a fellow at the Salk Institute in San Diego. The impact crater Szilárd on the lunar farside is named for him.

External links

Information

Leo Szilárd Online - an "Internet Historic Site" (first created March 30, 1995) maintained by Gene Dannen
Leo Szilárd's page at atomicarchive.com
Einstein's Letter to President Roosevelt - 1939
Annotated bibliography for Leo Szilárd from the Alsos Digital Library
Szilárd biography at Hungary.hu

Patents

-- Neutronic reactor -- E. Fermi, L. Szilárd, filed December 19, 1944, issued May 17, 1955