Nuclear Museum Logo
Nuclear Museum Logo

National Museum of Nuclear Science & History

Joseph Weinberg

PhysicistUniversity of California, Berkeley

Scientist

Joseph “Joe” Weinberg (1917-2002) was an American physicist.

Weinberg was a precocious young scientist who began his educational career at the age of 15 at the City College of New York. After receiving his M.S. from the University of Wisconsin, Madison, he arrived at the Radiation Lab at the University of California, Berkeley, in 1938. J. Robert Oppenheimer quickly took to the sharp young physicist, and Weinberg became part of an intimate group of Berkeley graduate students who worked with Oppenheimer at the Rad Lab. 

Many of those same students would receive opportunities to work at Los Alamos on the Manhattan Project. Weinberg, however, would not be given the chance, after it was discovered that he had ties to the Communist Party. In fact, in 1943, the FBI illegally recorded Weinberg discussing details about an atomic bomb–and the work being done at Berkeley to create one–with local Communist Party leader Steve Nelson.

In 1949, the House Un-American Activities Committee (HUAC) launched an investigation into Weinberg. At his hearing, he flatly denied ever having met Nelson. Despite this, HUAC branded him as “Scientist X” and accused him of spying for the Soviet government. Sensationalist media stories ran with the “Scientist X” moniker. One even accused Weinberg of hand-delivering uranium-235 to the Soviets.

The charges weighed heavily on Weinberg, and he was indicted for perjury in 1952. Even though he would eventually be acquitted less than a year later, he lost his professorship at the University of Minnesota and his career trajectory was negatively impacted. It would take him several years to restore his legitimacy in the field. He eventually became a distinguished professor at Syracuse University. 

Joseph Weinberg's Timeline
1917 Jan 19th Born in Queens, NY.
1938 Arrived at the Radiation Lab at the University of California, Berkeley.
1943 Illegally recorded by the FBI talking to Steve Nelson about the process of creating an atomic bomb.
1949 Apr 26th Denied ever having met Nelson during a HUAC hearing.
1952 May 23rd Indicted for committing perjury during his 1949 hearing.
1953 Mar 5th Acquitted of his perjury charges.
2002 Oct 22nd Died in Syracuse, NY.

Related Profiles

Robert Holmberg

Oak Ridge, TN

Robert Holmberg was born in Fort Dodge, Iowa, and began working on the Manhattan Project at the Chicago Met Lab and at Ames Laboratory in Iowa.

Gilbert Plass

Chicago, IL

Gilbert Plass was a Canadian physicist. Plass was born in 1922 in Toronto. He received a B.S. in physics from Harvard University before being hired to work on the Manhattan Project at the Chicago Met Lab, where he worked as an associate physicist.

Jane Hall

Hanford, WA

Jane Hamilton Hall (1915-1981) was an American physicist. Shortly after receiving her Ph.D. in physics from the University of Chicago in 1942, Hall became a research assistant at the Chicago Metallurgical Laboratory.

Norman H. Nachtrieb

Chicago, IL

Norman Harry Nachtrieb was an American chemist who worked on the Manhattan Project at the University of Chicago and Los Alamos.