Leo Szilard


Leo Szilard was born in Budapest in the Austro-Hungarian Empire in 1898. He was the son of a civil engineer and also
started showing skill and interest in physics and mathematics. He attended a technical school for engineering in 1916
but he was drafted into the army the following year. He was not there for long since he caught the Spanish flu and was
sent home to be hospitalized. He went back to school in 1919 but he left Hungary upon the rising anti-Semitic feelings, since he himself was Jewish. Szilard ended up getting a degree in Physics from Humboldt University of Berlin, where he had famous scientists such as Einstein as professors.

Upon reading an article by Earnest Rutherford about it not being possible to use atomic energy for practical use, Szilard became irritated and went on to discover the idea of nuclear chain reaction. He is said to have realized this on the day that he had read the article and while he was on his way to work. He went on to research which elements would produce a chain reaction. In 1938 he began doing research at Columbia University in Manhattan. He and another scientist Fermi found that the element that would work best to sustain a chain reaction is uranium. In 1942 Szilard was responsible for the first ever human controlled chain reaction by having boron-free graphite produced.

The Manhattan Project

Leo Szilard’s next big project was helping with the creation of the atomic bomb. In fact Szilard was responsible for starting the Manhattan Project by writing a letter to President Roosevelt that explained the possibility of other countries gaining nuclear power and encouraging the president to develop a program that would keep the United States in the nuclear weapons race. In 1939 Szilard sent this letter along with his old friend Albert Einstein’s signature on it, in order to use his famous name to secure his proposal. This letter led to the creation of the Manhattan project. Szilard along with Fermi created the first neutronic reactor and his greatest contribution was the cotrolled nuclear chain reaction that could be used as a power source for an atomic bomb. As the project began to be more and more controlled by the government, Szilard become more resentful. He was especially upset that he could not prevent the destructive use of the atomic bomb through possibly having a test explosion that would be viewed by the Japanese and encourage them to surrender but that would not kill any one. He was very outspoken and criticized the way the project was being run by military officials who did not know enough about science to understand the implications of atomic weapons that way that he and his fellow scientists did. He believed that as a scientist who helped create this bomb he was morally responsible for its use.

After the Manhattan Project

After the project, Leo Szilard had suffered through a long war and became passionate about protecting human life and freedoms. He did not support the use of the atomic weapons, due to the fact that they could easily hurt civilian populations. President Truman did not listen to the protests of Szilard and other scientists and instead chose to use atomic bombs on Hiroshima and Nagasaki.

After the War

Szilard became fearful of the power of atomic bombs getting into the wrong hands, even into the hands of our own government. He decided therefore to switch from researching physics to molecular biology. In 1950 though Szilard came up with the Cobalt bomb, which was a type of nuclear weapon that he said could destroy all life on earth. He then went on to have several interviews about his work and the war. One such interview was titled “President Truman Didn’t Understand”. He discussed the fact that it would not have been necessary to use the bomb if he had just tried to negotiate with them. Szilard went on to marry Gertrud Weiss in 1951 but was diagnosed with bladder cancer soon after in 1960. He spent his last few years still trying to warn people of the threat of a nuclear war through groups such as the Council for a Livable World. Leo Szilard passed away in 1964 from a heart attack at the age of sixty-six.


Szilard was awarded many honors for his work during his lifetime. These included the Atoms for Peace Award which he received in 1959, a spot in the National Inventors Hall of Fame, and the Humanist of the year award in 1960. He even had a crater on the moon named after him.