Chronology of Atomic Age:
- 1896 — Henri Becquerel notices that uranium gives off an unknown radiation which fogs photographic film.
- 1898 — Marie Curie discovers thorium gives off a similar radiation. She calls it radioactivity.
- 1903 — Ernest Rutherford begins to speak of the possibility of atomic energy.
- 1905 — Albert Einstein formulates the special theory of relativity which explains the phenomenon of radioactivity as mass-energy equivalence.
- 1911 — Ernest Rutherford formulates a theory about the structure of the atomic nucleus based on his experiments with alpha particles.
- 1932 — James Chadwick discovers the neutron.
- 1934 — Enrico Fermi begins bombarding uranium with slow neutrons; Ida Noddack predicts that uranium nuclei will break up under bombardment by fast neutrons (Fermi does not pursue this because his theoretical mathematical predictions do not predict this result.).
- 17 December 1938 – Based on detailed theoretical predictions by Lise Meitner, Otto Hahn and Fritz Strassmann experimentally confirm nuclear fission (a term coined by Meitner’s associate Otto Robert Frisch) by bombarding uranium with fast neutrons.
- 11 October 1939 — The Einstein–Szilárd letter, suggesting that the United States construct an atomic bomb, is delivered to President Franklin Delano Roosevelt. Roosevelt signs the order to build an atomic bomb on 6 December 1941.
- 26 February 1941 — Discovery of plutonium by Glenn Seaborg and Arthur Wahl.
- September 1942 — General Leslie Groves takes charge of the Manhattan Project.
- 2 December 1942 — The first self-sustaining nuclear chain reaction takes place in Chicago, United States, at the Chicago pile - 1.
- 16 July 1945 — The first atomic bomb is tested near Alamogordo, New Mexico, United States in the successful Trinity test.
- 6 August 1945 — The atomic bomb is first deployed as a military weapon (by the United States) in the bombing of Hiroshima, Empire of Japan.
- 5 September 1951 — The U.S. Air Force announces the awarding of a contract for the development of an "atomic-powered airplane".
- 1 November 1952 — The first hydrogen bomb, largely designed by Edward Teller, is tested at Eniwetok Atoll.
- 8 December 1953 — U.S. President Dwight D. Eisenhower, in a speech before the UN General Assembly, announces the Atoms for Peace program to provide nuclear power to developing countries.
- 21 January 1954 — The first nuclear submarine, the USS Nautilus (SSN-571), is launched into the Thames River near New London, Connecticut, United States.
- 27 June 1954 — The first nuclear power plant begins operation near Obninsk, USSR.
- 17 September 1954 — Lewis L. Strauss, chairman of the U.S. Atomic Energy Commission, states that nuclear energy will be “too cheap to meter”.
- 29 September 1957 — 200+ people die as a result of the Mayak nuclear waste storage tank explosion in Chelyabinsk, Soviet Union. 270,000 people were exposed to dangerous radiation levels.
- 1957 to 1959 — The Soviet Union and the United States both begin deployment of ICBMs.
- 1958 — The neutron bomb, a special type of tactical nuclear weapon developed specifically to release a relatively large portion of its energy as energetic neutron radiation, is invented by Samuel Cohen of the Lawrence Livermore National Laboratory.
- 1960 — Herman Kahn publishes the book On Thermonuclear War.
- November 1961 — In Fortune magazine, an article by Gilbert Burck appears outlining the plans of Nelson Rockefeller, Edward Teller, Herman Kahn, and Chet Holifield for the construction of an enormous network of concrete lined underground fallout shelters throughout the United States sufficient to shelter millions of people to serve as a refuge in case of nuclear war.
- 12 October 1962 to 28 October 1962 — The Cuban Missile Crisis brings Earth to the brink of nuclear war.
- 10 October 1963 — The Partial Test Ban Treaty goes into effect, banning above ground nuclear testing.
- 26 August 1966 — The first pebble bed reactor goes on line in Julich, West Germany (some nuclear engineers think that the pebble bed reactor design can be adapted for atomic powered vehicles).
- 28 March 1979 — The Three Mile Island accident occurs at the Three Mile Island Nuclear Generating Station near Harrisburg, Pennsylvania, dampening the enthusiasm of many in the United States for nuclear power.
- 26 April 1986 — The Chernobyl disaster occurs at the Chernobyl Nuclear Power Plant near Pripyat, Ukraine, USSR, reducing the enthusiasm for nuclear power among many people in the world.
- 8 December 1987 — The Intermediate-Range Nuclear Forces Treaty is signed in Washington 1987. Ronald Reagan and Mikhail Gorbachev agreed after negotiations following the October 11–12 1986 Reykjavík Summit to go farther than a nuclear freeze — they agreed to reduce nuclear arsenals. IRBMs and SRBMs were eliminated.
- 1990–Present — Nuclear power is the primary source of electricity in France. Throughout the 90's and 00's, France produces over three quarters of its power from nuclear sources (78.8%), the highest percentage in the world during these 2 decades.
- 31 July 1991 — As the Cold War ends, the Start I treaty is signed by the United States and the Soviet Union, reducing the deployed nuclear warheads of each side to no more than 6,000 each.
- 2006 — Patrick Moore, a founder of Greenpeace and other environmentalists such as Stewart Brand suggest the deployment of more advanced nuclear power technology for electric power generation such as pebble bed reactors, to combat global warming.
- 21 November 2006 — Implementation of the ITER fusion power reactor project near Cadarache, France is begun. Construction is to be completed in 2016 with the hope that the research conducted there will allow the introduction of practical commercial fusion power plants by 2050.
- 2006-2009 — A number of nuclear engineers begin to suggest that, to combat global warming, it would be more efficient to build nuclear reactors that operate on the thorium cycle.
- 11 March 2011 — A tsunami resulting from the Tōhoku earthquake causes severe damage to the Fukushima I Nuclear Power Plant in Japan, causing partial nuclear meltdowns in several of the reactors. Many international leaders express concerns about the accidents and some countries re-evaluate existing nuclear energy programs. On 11 April 2011 this event was rated level 7 on the International Nuclear Event Scale by the Japanese government's nuclear safety agency. Other than the Chernobyl disaster, it is the only nuclear accident to be rated at level 7, the highest level on the scale.