Physicist Leo Szilard, with Eleanor Roosevelt at his side, at a meeting in Washington, D.C.
Physicist Leo Szilard, with Eleanor Roosevelt at his side, at a meeting in Washington, D.C. — Courtesy of Mandeville Special Collections, UC San Diego

The physicist known as the “genius in the shadows” is being drawn into the spotlight a half-century after his death.

On Wednesday, UC San Diego will present a retrospective on the late Leo Szilard of La Jolla, who came up with the idea for the nuclear chain reaction. The breakthrough helped lead to the Manhattan Project, America’s successful effort to build the first atomic bombs.

Szilard played a key role in the project. But he was a behind-the-scenes operator, ceding attention to other scientists. He took the same approach years later while advising General Atomics of San Diego on nuclear reactors, and when he helped to create the Salk Institute for Biological Studies in La Jolla.

Author William Lanouette— K.C. Alfred
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Szilard’s story will be brought to life this week by historian William Lanouette of North Park, author of the acclaimed book “Genius in the Shadows: A Biography of Leo Szilard, the Man Behind the Bomb.” Lanouette will give a public talk about the physicist at UC San Diego’s Faculty Club, starting at 11 a.m.

The following is an edited version of his recent interview with U-T San Diego.

Q: Why do you call Szilard a genius, and how could someone like this have fallen into the shadows?

A: He made surprising discoveries in many scientific fields, thanks in part to his freewheeling approach to knowledge and his lateral thinking across different disciplines.

In nuclear physics, he conceived the nuclear chain reaction and the critical mass to sustain it, and with Enrico Fermi co-designed the world’s first nuclear reactor. He thought of and named the breeder reactor that makes more fuel than it consumes. And he devised the Szilard-Chalmers effect for isotope separation.

In biology, he devised a way to clone living cells, and he saw that enzymes control their growth by an on-off process called negative feedback. This insight gained others the Nobel Prize, for which they credited Szilard. His studies of cancer and of memory are praised today for their early insights.

Szilard remained in the shadows by choice, enjoying the thrill of discovery for its own sake and eagerly sharing ideas with those who could follow them to completion. He rarely taught and never stayed at an academic institution long enough to make a name in a specialized field.

Francois Jacob, one of the biologists who owes his 1965 Nobel Prize to Szilard, called him an “intellectual bumblebee” for nurturing and enriching science freely and broadly. As Jonas Salk said, “Leo cared not to carry the torch, but simply to light it ...”

Q: You say he had a tremendously creative mind. What made him so pragmatic yet freewheeling?

A: Until Szilard went to high school, he studied at home with tutors and a governess and was encouraged to think creatively on his own. But his daydreams often had a practical purpose — to solve some household problem, because early on he wanted to be an engineer like his dad.

He developed intense powers of concentration, then applied them to fun projects such as making a camera from items found around the house, building a crystal-radio telegraph or wiring an antique tea kettle to boil water. In a sense, his mind was always at play.

Q: How did his work turn away from such things as cameras and telegraphs to developing weapons?

A: Science fiction. He met H.G. Wells in London in 1929, and in 1932 read Wells’ “The World Set Free,” written in 1913 about a worldwide atomic war in the 1950s. Wells and Szilard also speculated that the only way for humans to escape Earth to visit other planets was if they were powered by atomic energy. But neither knew how that could happen.

Q: There are few “aha!” moments in science, and Szilard had one with the nuclear chain reaction. How did that moment come to him?

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A: Szilard knew that the neutron, a subatomic particle with no electrical charge, had been discovered in 1932. In 1933, on a street corner waiting for a traffic light to change, it hit him: perhaps by the way the bulbs blend one into another, red to amber to green. If a neutron could penetrate and split an atom’s nucleus or core, then release two neutrons, it might set off a chain reaction releasing energy for making electricity and for making bombs. Within months, Szilard patented the chain reaction.

Q: Working with Albert Einstein, Szilard proposed and drafted a letter to President Franklin D. Roosevelt that pointed to the possibilities of developing an atomic bomb. That led to the Manhattan Project. Did Szilard agonize about the horrific nature of what they were proposing?

A: He never agonized, and after the war said it was the only rational thing to do at the time, given a possible German A-bomb. But just after Einstein’s letter was ready for delivery, Szilard was moved to write his own version of the Ten Commandments. He knew the world would never be the same again, scientifically or morally.

Q: Ten Commandments?

A: Szilard and Einstein enjoyed talking about religion and ethics, so the grave implications of sending off the Einstein letter to FDR in 1939 may have rekindled some of their speculations. But, as always, Szilard was contrary. Instead of “Honor thy father and thy mother,” Szilard commanded, “Honor children. Listen reverently to their words and speak to them with infinite love.” Instead of “Thou shalt not kill,” he wrote: “Do not destroy what you cannot create.” And for desiring forbidden things, he wrote: “Touch no dish, except that you are hungry.”

UC San Diego to digitize Leo Szilard's papers

Q: When did Szilard first visit La Jolla?

A: Szilard first came here in 1957 to consult on novel ideas for nuclear-reactor designs at General Atomics. He and Enrico Fermi had designed the world’s first nuclear reactor in 1939, and Szilard was a recognized pioneer in the field.

Clearly, he loved the weather, spent little time at General Atomics’ office and worked outdoors at his hotel. ... He returned the next summer.

Q: So he must have become friends with the people who founded General Atomics?

A: Friends and former colleagues. General Atomics was founded by Manhattan Project physicist Frederick de Hoffman, and Szilard was invited to work there by Edward Creutz, a colleague on the project.

Q: How did Szilard come to know Jonas Salk?

A: At various biology conferences, beginning in 1957, Szilard tried to interest Salk in the idea of creating a research institute that combined hard science with the study of the social consequences. At first Salk wasn’t interested, but Szilard persisted. He enlisted several American and British scientists in his scheme, and said Salk could be an affiliate member.

Q: Szilard was a man of strong convictions. Did this put him at odds with Salk when they were discussing the creation of the institute?

A: Definitely. Salk wanted a study center in Pittsburgh, where he had conducted his polio virus research. But Szilard insisted that no first-class scientists would want to move there, then conspired with colleagues to locate a new institute in La Jolla, near the new UC San Diego campus and the Scripps Institution of Oceanography.

Q: Were his final years difficult?

A: Szilard always maintained “a narrow margin of hope” for everything he did, and once the radiation treatment he devised in 1960 eradicated his bladder cancer, he enjoyed being the center of attention from friends and the news media. That year in New York, he even met Soviet Premier Nikita Khrushchev and gained from him agreement to install a Moscow-Washington “hotline.”

Q: What was Szilard’s state of mind in the final year or two of his life?

A: Szilard was frustrated by the Kennedy administration’s policies, and moved to a hotel near the White House to lobby for arms control. In 1962, he founded the Council for a Livable World, the first political action committee for arms control and disarmament.

Q: You spent years studying Leo Szilard’s life. Is there something odd or unusual that sticks in your mind about him?

A: His sense of humor. Szilard saw the world as a frightful place, and when striving to make it safer and saner he dealt with his fears by jokes and jests. Humor freed him to see the world as a place alive with meaning and with mirth.