A Nuclear Physicist Who Hated the Bomb Is Born

Joseph Rotblat would become the only conscientious objector to walk off the Manhattan Project, once he learned what America really wanted the bomb for.

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Joseph Rotblat's Los Alamos badge, from 1944, on the backdrop of a picture of an anti-nuclear protest in Nantes, inspired by the nuclear disasters in Japan.
Joseph Rotblat's Los Alamos badge, from 1944, on the backdrop of a picture of an anti-nuclear protest in Nantes, inspired by the nuclear disasters in Japan.Credit: Nantes: AFP, Rotblat: FoliesTrévise, Wikimedia Commons

November 4, 1908, is the birthdate of Joseph Rotblat, the Polish-born nuclear physicist, an early pioneer of nuclear fission, who walked away from the Manhattan Project, and devoted much of the rest of his life to the cause of nuclear disarmament. For those latter efforts, Rotblat, together with the Pugwash Conferences on Science and World Affairs, of which he was co-founder, won the Nobel Peace Prize in 1995.

Jozef Rotblat was born in Warsaw to Zygmunt Rotblat and the former Sonja Krajtman. Zygmunt was an importer and distributor of newsprint, and a breeder of horses. Following World War I, however, the family went from being well-off to impoverishment, and Joseph, whose parents had dreamt of his becoming a rabbi, left school at 12 to work as an electrician’s assistant.  

Rotblat continued to study independently, however, with sufficient success that in about 1923, he was accepted into the physics department at the Free University of Poland. In 1938 he received his doctorate in physics at the Radiological Laboratory of the Scientific Society of Warsaw.

Escaped the Nazis by a whisker

In the years preceding World War II, Rotblat worked on nuclear fission, doing research that suggested that the release of neutrons from the splitting of an atomic nucleus could lead to a chain reaction and massive explosion. 

In early 1939, he traveled to Liverpool, to work in the lab of James Chadwick, winner of the 1935 Nobel Prize for Physics for his discovery of the neutron. That summer, he returned to Warsaw to arrange for his wife, the former Tola Gryn, to join him in England.

Tola was unwell, however, on the day of Joseph’s departure, and they agreed that she would travel when she could. That never happened because two days later, on September 1, Germany invaded Poland, and, despite his best efforts, Rotblat was unsuccessful in getting Tola, a Jew, out of Poland. After the war, he learned that she had died in Majdanek concentration camp, probably in 1942. He never married again.

Though he had misgivings about the military potential of nuclear fission, Rotblat knew that the Germans were rushing to harness the power of the atom, and so continued his work after the start of the war. In 1944, though still a Polish national, he was part of the British team invited to New Mexico to participate in the Manhattan Project to develop an atomic bomb.

But later that year, he was shocked to hear Maj.-Gen. Leslie Groves, director of the project, declare that the real purpose for developing the bomb was to deter the Soviet Union. And, when it became clear by the end of 1944 that the Germans had abandoned their bomb-building effort, Rotblat resigned from the Manhattan Project, making him the only scientist to leave for reasons of conscience.

Manhattan Project leader, U.S. Major General Leslie Groves, conferring with James Chadwick, the head of the British Mission, c. 1945.Credit: Los Alamos National Laboratory, Wikimedia Commons

Back in the United Kingdom, Rotblat rechanneled his work to peaceful uses of nuclear energy, not only on medical applications but also on research on the dangers of nuclear fallout.

Enemy of thermonuclear war

In 1955, Rotblat was a signatory to the manifesto drafted by Bertrand Russell and Albert Einstein, after the detonation of the first hydrogen bomb, warning of the dangers of thermonuclear warfare. Two years later, he was one of organizers of the first conference, held in Pugwash, Nova Scotia, in Canada, of scientists from around the world, for the purpose of discussing, in an off-the-record setting, nuclear weapons and similar issues related to the future of humanity.

Though there was suspicion at the political level about the annual Pugwash meetings, especially during the height of the Cold War, the conferences offered a singular opportunity for scientists from all sides to converse, and sometimes even to carry important messages between their respective nations.

In its obituary for Rotblat, The New York Times noted that historians credit the Pugwash endeavor with “laying the groundwork for the Partial Test Ban Treaty of 1963, the Nonproliferation Treaty of 1968, the Anti-Ballistic Missile Treaty of 1972, the Biological Weapons Convention of 1972 and the Chemical Weapons Convention of 1993.”  

For their efforts, both the Pugwash Conferences and Rotblat individually, as the founder of Pugwash, were awarded with the Nobel Peace Prize, in 1995.

Joseph Rotblat died on August 31, 2005, at the age of 96.