atomic bomb: Quick Facts

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Facts

Also Known As	atom bomb • fission bomb

Photos and Videos

Diagram showing the sequence of uranium nucleus fission after being struck by a neutron: the nucleus absorbs the neutron, deforms, splits into fragments, releases more neutrons and gamma rays, and emits beta particles as the fragments decay. Labels identify neutrons, protons, beta particles, and gamma rays, with accompanying explanatory text.

Diagram showing three nuclear weapon designs: a gun-assembly fission bomb with uranium-235 and a conventional explosive, an implosion fission bomb with a plutonium-239 core surrounded by explosive lenses, and a boosted-fission bomb with a plutonium core, uranium tamper, and fusion fuel, all labeled with their main components inside cutaway metal casings.

Atomic bombing of Hiroshima

J. Robert Oppenheimer and Leslie R. Groves

Infographic titled The First Atomic Bombs, showing key facts about the first atomic bomb test in New Mexico and the bombings of Hiroshima and Nagasaki in Japan during World War II. Includes diagrams of bomb mechanisms, a map of Japan with target cities, and illustrations of the Little Boy and Fat Man bombs, along with details on deployment, explosive yield, and estimated casualties.

Infographic explaining the atomic bombing of Hiroshima on August 6, 1945, including a map of Japan, details about the Little Boy bomb, casualty statistics, symptoms of radiation injury, and information on Hiroshima's rebuilding and peace memorials. Key figures show about 140,000 deaths by year's end, symptoms such as hair loss and internal bleeding, and the city's postwar transformation into a peace symbol.

Hiroshima, Japan, after the atomic bomb strike

Hiroshima, Japan: August 1945

World War II: total destruction of Hiroshima, Japan

Split image showing Dr. J. Robert Oppenheimer at a chalkboard on the left and actor Cillian Murphy portraying Oppenheimer with a cigarette and hat on the right.

Fission of a uranium nucleus by a neutron

What is the difference between nuclear fission and fusion?

The environmental effects of nuclear radiation

Watch U.S. B-29 Superfortress Enola Gay decimate Hiroshima with a nuclear bomb in the Pacific War

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Topics

gun-assembly fission bomb The First Atomic Bombs Tested and Used During World War II Today in History—July 16: The Day the End of the World Began Atomic Bombing of Nagasaki: Infographic Atomic Bombing of Hiroshima: Infographic Timeline of the Manhattan Project 70 Years After Hiroshima atom Today in History—July 5: The Atomic Origins of the Bikini thermonuclear bomb neutron bomb

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Key People

Vannevar Bush with Differential Analyzer, c. 1935

Vannevar Bush

American engineer

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Igor Vasilyevich Kurchatov

Soviet physicist

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Theodore Hall

American-born physicist and spy

Luis Alvarez

Luis Alvarez

American physicist

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Klaus Fuchs

German physicist and spy

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Karl Taylor Compton

American physicist

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William Penney, Baron Penney

British physicist

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Yves-André Rocard

French mathematician and physicist

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William Penney

British scientist

J. Robert Oppenheimer

J. Robert Oppenheimer

American physicist

Abdul Qadeer Khan

Abdul Qadeer Khan

Pakistani scientist

Peierls, Sir Rudolf Ernst; Dirac, P.A.M.; Pauli, Wolfgang

Sir Rudolf Ernst Peierls

British physicist

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Stanislaw Ulam

American scientist

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Elda Emma Anderson

American physicist