Atomic bomb

On April 14, 1932, John Cockcroft and E.T.S. Walton of Great Britain successfully split the atom, providing experimental proof for Einstein's Theory of Relativity.

In 1939, Robert Oppenheimer recognizes the potential military applications of nuclear fission, a crucial development in the field of atomic energy.

In September 1939, Albert Einstein contacts President Roosevelt to discuss the use of uranium as a new energy source, leading to the establishment of the Committee on Uranium.

In October 1939, a meeting took place between physicists Einstein and Szilard with President Roosevelt, where they discussed the possibility of Germany developing an atomic bomb. Einstein's letter emphasized the urgency for the U.S. Government to speed up experimental work on powerful bombs.

Plutonium was discovered on February 23, 1941, by Glenn Seaborg, Edwin McMillan, Joseph W. Kennedy, and Arthur Wahl, which played a crucial role in the development of nuclear weapons.

On June 15, 1941, the MAUD Committee approved a report stating the feasibility of building a uranium bomb.

On October 9, 1941, President Franklin D. Roosevelt gave the authorization for the development of an atomic weapon, marking a significant milestone in the Manhattan Project.

On January 19, 1942, President Roosevelt approved the development of an atomic bomb, leading to the establishment of the Metallurgical Laboratory at the University of Chicago under Arthur Compton. This decision had far-reaching consequences for the course of history.

On June 18, 1942, the Army Corps of Engineers formally established the Manhattan District, which played a crucial role in the development of the atomic bomb during the Manhattan Project. This marked a significant milestone in the history of nuclear weapons.

On July 27, 1942, the first batch of irradiated uranium is delivered to the Chicago Met Lab, marking a significant step in the Manhattan Project's efforts to develop the atomic bomb.

President Franklin D. Roosevelt gives approval for the development of an atomic weapon.

In August 1942, Glenn Seaborg successfully isolates pure plutonium through a separation process suitable for large-scale industrial use, a crucial development for the Manhattan Project.

On August 29, 1942, a positive status report on Oppenheimer's theoretical study group is delivered to the Secretary of War, highlighting the progress and concerns regarding project organization and leadership.

On September 13, 1942, the S-1 Executive Committee suggests constructing a pilot plant based on Ernest O. Lawrence's cyclotrons for the separation of uranium isotopes, a crucial step in the Manhattan Project.

On December 2, 1942, the first controlled nuclear chain reaction took place at the University of Chicago, marking a significant milestone in the development of nuclear technology.

General Leslie Groves selects Hanford, WA as a site for plutonium production.

Construction begins at Oak Ridge, TN on buildings for the Y-12 Plant, the electromagnetic U-235 separation plant.

Richard Tolman writes to Oppenheimer about using explosives to collapse a shell into a critical mass, an early reference to implosion.

J. Robert Oppenheimer suggests recruiting George Kistiakowsky, the leading explosives research director at The Office of Scientific Research and Development, to aid an expanded implosion effort.

DuPont engineers release reactor design drawings for the first Hanford, WA plutonium production pile, 100-B, allowing construction to begin.

Site preparation starts for the B-100 plutonium production reactor, B Reactor, at Hanford, WA.

First concrete is poured for the K-25 Plant building at Oak Ridge, TN.

The X-10 Graphite Reactor pile goes critical at Oak Ridge, TN, producing substantial amounts of plutonium for research purposes. Manhattan Project Governing Board approves an ambitious implosion research program.

The first B-29 modifications begin at Wright Field, Ohio to adapt it for carrying atomic bombs.

George Kistiakowsky takes over as the head of implosion research at Los Alamos, replacing Seth Neddermeyer. He becomes a full-time staff member, leading the efforts in developing implosion techniques for the atomic bomb project.

Experimental drop tests of dummy atomic bombs commence at Wendover, Utah, to simulate the behavior of the bombs during deployment. This testing phase is crucial for assessing the functionality and effectiveness of the atomic bomb designs.

The initial sample of reactor-generated plutonium is received at Los Alamos from Oak Ridge, Tennessee. Emilio Segre's analysis reveals a high spontaneous fission rate due to Pu-240 contamination, posing challenges for bomb assembly.

Geoffrey Taylor, a British scientist who joined Los Alamos in May 1944, identified issues with implosion instability, particularly the Rayleigh-Taylor instability. His observations led to a conservative design approach to minimize potential instability.

In May 1944, the first test of the exploding wire detonator took place at Los Alamos. This detonator was crucial for achieving precise and reliable simultaneous detonation for implosion experiments.

On June 18, 1944, General Leslie Groves initiated the construction of the S-50 Plant at Oak Ridge, Tennessee. This plant was intended for liquid thermal diffusion uranium enrichment and had to be completed in a tight timeframe of three months.

On July 4, 1944, J. Robert Oppenheimer reveals Emilio Segre’s spontaneous fission measurements to the Los Alamos staff. This discovery led to the abandonment of the planned plutonium gun and prioritization of implosion research, marking a significant turning point for the Manhattan Project.

The B Reactor at Hanford Site in Washington state achieves criticality, a crucial step towards full-scale plutonium production for the Manhattan Project's atomic bomb development.

Otto Frisch conducts the Dragon experiment, dropping a U-235 hydride slug through a barely subcritical U-235 hydride assembly, creating the world's first assembly critical through prompt neutrons alone.

Curtis LeMay takes command of the Twentieth Air Force in the Marianas, which contains 345 aircraft. The first stage of the K-25 Plant is charged with uranium hexafluoride and begins operation.

Robert Bacher reports to Oppenheimer that a Po-210/Be-9 implosion initiator is possible, although still to be designed.

Los Alamos, NM receives its first plutonium shipment from Hanford, WA.

In April 1945, the Military Policy Committee of the Manhattan Project designated Japan as the primary target for any future atomic bomb, setting the stage for the devastating events that would follow.

On June 16, 1945, the Scientific Panel of the Interim Committee, including Enrico Fermi and J. Robert Oppenheimer, concludes that there is no acceptable alternative to using an atomic weapon against Japan.

By June 21, 1945, the first implosion initiator is prepared, a crucial component in the development of the atomic bomb.

On June 24, 1945, Otto Frisch confirms the satisfactory design of the implosion core after criticality tests, marking a significant step in the atomic bomb development.

On July 11, 1945, the assembly of Gadget, the first atomic bomb, commences, marking a crucial stage in the preparation for the Trinity Test.

On July 12, 1945, the plutonium core and components of the Gadget, the first atomic bomb, departed from Los Alamos, New Mexico, for the test site separately.

At 1300 hours on July 13, 1945, the assembly of the Gadget, including its explosive lens, uranium reflector, and plutonium core, was completed at Ground Zero.

On July 14, 1945, the Gadget was lifted to the top of the 100-foot test tower for final preparations, including the installation of detonators.

The Gadget, the world's first atomic test device, was successfully detonated on July 16, 1945, at the Trinity Site in New Mexico, marking a significant milestone in the development of nuclear weapons.

On July 19, 1945, J. Robert Oppenheimer proposed reworking the U-235 from Little Boy into uranium/plutonium composite cores for making more implosion bombs, but General Leslie Groves rejected the idea.

The world's first atomic detonation occurred in the Trinity Test at Alamogordo, New Mexico.

President Truman gave the order for the use of atomic bombs.

On August 6, 1945, the United States dropped an atomic bomb on Hiroshima, leading to widespread destruction and loss of life, marking a turning point in World War II.

Three days after the bombing of Hiroshima, on August 9, 1945, the United States dropped a second atomic bomb on Nagasaki, further devastating the city and hastening Japan's surrender.

The United States distributes warning leaflets in Nagasaki regarding the potential of another atomic bomb being dropped, a day after the devastating atomic bomb was actually detonated in the city.

The UN General Assembly passes its first resolution urging for the total eradication of nuclear weapons and establishes a commission to tackle the issue.

Louis Slotin received a lethal dose of radiation while conducting an experiment with beryllium and plutonium, causing a criticality accident.

Louis Slotin succumbed to the effects of radiation exposure from the failed experiment he conducted at Los Alamos.

The U.S. conducted its first postwar nuclear test, Operation Crossroads, at Bikini Atoll to study the impact of nuclear weapons on naval warships.

The U.S. military detonated a 23 kiloton atomic bomb underwater at Bikini Atoll as part of Operation Crossroads, causing severe contamination to naval vessels.

On August 1, 1946, President Truman signed the Atomic Energy Act which established the Atomic Energy Commission.

On September 5, 1946, the FBI questioned U.S. scientist Robert Oppenheimer about his contacts with a Communist, Professor Haakon Chevalier.

On November 10, 1946, a team of Soviet scientists, headed by Igor Kurchatov, started the assembly of the first full-scale nuclear reactor.

On December 25, 1946, Soviet scientists achieved a nuclear chain reaction, marking one of the initial steps in building the atomic bomb.

On December 31, 1946, Soviet scientists reviewed espionage accounts of U.S. physicist Edward Teller's design for the hydrogen bomb known as 'classical super.'

On January 1, 1947, the Atomic Energy Commission assumed control of the Manhattan Engineer District, which was responsible for the development of the atomic bomb during World War II.

On August 25, 1947, the Manhattan Engineer District was officially abolished, marking the formal end of the Manhattan Project, which was a significant scientific and military undertaking during World War II.

The U.S. military conducted the first fission weapon test using a levitated core design in Operation Sandstone.

The Soviet Union conducts a successful test of its inaugural nuclear weapon named 'First Lightning' in Semipalatinsk, Kazakhstan, marking its entry as the second nation to possess and test a nuclear bomb.

The US military conducts the Dog Shot of Operation Buster, a 21 kiloton airdrop fission bomb with a composite plutonium-uranium core as part of Operation Desert Rock I.

The United States conducts the “Sugar” nuclear test on November 19, 1951 at the Nevada Test Site, yielding 1.2 kilotons, as part of Operation Buster-Jangle and Operation Desert Rock II.

The United States conducts the Shot Able nuclear test, the first in the Operation Tumbler Snapper series, on April 1, 1952, with a yield of 1 kiloton.

The United States conducts Shot Charlie, the third in the Operation Tumbler Snapper series, on April 22, 1952, yielding 31 kilotons, as part of the Desert Rock IV exercises.

The United States conducts Shot Dog, the fourth in the Operation Tumbler Snapper series, on May 1, 1952, yielding 19 kilotons, as part of the Desert Rock IV exercises.

On May 9, 1952, the U.S. conducted the 'George' test in the Pacific, which involved a large fission bomb triggering the first thermonuclear reaction.

In September 17, 1952, U.S. physicist Marshall Holloway was named the leader of the H-bomb project, while Edward Teller left Los Alamos shortly afterwards.

On September 24, 1952, the Soviet Union conducted its second nuclear test, involving an improved plutonium bomb.

The UK tests its first atomic bomb, known as Hurricane, on October 3, 1952.

The United States tests its first ever thermonuclear device, the Mike Shot, on November 1, 1952, at Eniwetok Atoll, yielding 10 megatons of TNT.

The United States detonates a 17-megaton hydrogen bomb, known as "Bravo", at Bikini Atoll in the Pacific Ocean. This event resulted in the contamination of a Japanese fishing boat, Lucky Dragon, and affected residents of Rongelap and Utirik.

The Soviet Union detonates the most powerful bomb ever, the Tsar Bomba, with a yield of 58 megatons over Novaya Zemlya in northern Russia.

On October 10, 1963, the Limited Nuclear Test Ban Treaty, which prohibits nuclear weapon tests in the atmosphere, outer space, and underwater, goes into effect.

China successfully detonates its first atomic bomb at the Lop Nor testing site in Xinjiang Province. This marks China's entry into the nuclear arms race.