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Discovery of Radioactivity
• Physicist Antoine Henri Becquerel discovers natural radioactivity.
• Marie and Pierre Curie further study radioactive elements, leading to the understanding of atomic decay.
• These early studies lay the groundwork for nuclear science and atomic energy. -
Discovery of the Neutron
• James Chadwick discovers the neutron, a subatomic particle with no electric charge.
• This discovery allows scientists to understand nuclear fission.
• Neutrons become essential in triggering nuclear reactions for bombs. -
Einstein’s Letter to President Roosevelt
• Physicists Leo Szilard and Albert Einstein were deeply concerned about the potential for Nazi Germany to develop an atomic bomb.
• Albert Einstein and physicist Leo Szilard warn Roosevelt about the potential of a German atomic bomb through a letter.
• This letter leads to the establishment of the Manhattan Project. -
The Manhattan Project Begins
• The U.S. government starts a top-secret program, known as the Manhattan Project, with the goal of developing the world’s first atomic bomb before Nazi Germany could make one. The project is kept highly confidential, with only a small group of people aware of its true purpose.
• Headed by physicist J. Robert Oppenheimer, the project gathers top scientists.
• The government set up secret facilities established in Los Alamos, Oak Ridge, and Hanford to keep the research hidden and secure. -
First Nuclear Chain Reaction
• The first human-made self-sustaining nuclear chain reaction was initiated in Chicago Pile-1 (CP-1) during an experiment led by Physicist Enrico Fermi. CP-1 was the world's first artificial nuclear reactor.
• This experiment proves that atomic energy can be harnessed.
• The success pushes forward the development of a nuclear bomb. -
Bombing of Hiroshima and Nagasaki
• The U.S. drops the atomic bomb “Little Boy” on Hiroshima, Japan - August 6, 1945.
• It's estimated that 140,000 people died instantly, with 78,000 injured.
• Many of the survivors faced terrible side effects from the radiation and long term health issues.
• A second bomb, “Fat Man,” is dropped on Nagasaki - August 9, 1945.
• It's estimated that 74,000 people died instantly, with 75,000 injured.
• This bombing, along with Hiroshima, leads to Japan’s surrender and the end of World War II. -
Trinity Test
• The first atomic bomb is tested in the New Mexico desert.
• The explosion, nicknamed "Trinity," produces an intense flash and a mushroom cloud.
• This successful test confirms the bomb’s destructive power and readiness for wartime use. -
Nuclear Arms Race Begins
• The Soviet Union successfully tests its first atomic bomb, nicknamed "First Lightning," in Kazakhstan. This surprises the U.S., as they didn’t expect the Soviet Union to develop nuclear weapons so quickly. With this test, the Soviet Union becomes the second country in the world to have an atomic bomb, ending the U.S.'s monopoly on nuclear weapons.
• The U.S. and Soviet Union build up nuclear arsenals during the Cold War.
• Competition increases global tension and leads to more nuclear tests. -
Treaty on the Non-Proliferation of Nuclear Weapons (NPT)
• The NPT is signed by multiple countries to prevent the spread of nuclear weapons beyond the few countries that already have it, like the U.S., the Soviet Union, the U.K., France, and China.
• It aims to promote peaceful nuclear energy and disarmament.
• The treaty is considered one of the most important agreements for global security and aims to reduce the risk of nuclear war by limiting who can develop nuclear weapons.
• Signed on July 1, 1968 - effective March 5, 1970 -
Modern Nuclear Disarmament Efforts (2000's-present)
• Various nations and organizations work to reduce nuclear arsenals.
• Global summits and treaties, like the Treaty on the Prohibition of Nuclear Weapons, focus on total disarmament.
• Despite progress, concerns remain over nuclear tensions and the risk of proliferation.