Uhlig Nuclear Technological Development

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Source: National Archives

Test Ban Treaty

The Test Ban Treaty was created and signed to prevent the further environmental contamination by nuclear testing. The efforts for a treaty began in the Subcomittee of Five, consisting of the US, the UK, Canada, France, and the USSR. The Subcomittee was working under the UN disarmament Commission. Public interest was important and active, and the process itself was tumultuous. They had to reconcile different philosophies about arms control, defense, and security. The treaty prohibited testing anywhere on Earth, land or sea, or in space.

• An excerpt from the treaty

Batter my heart, three-person'd God

Source: OSTI

Trinity Test

The Trinity Test was the first nuclear weapon ever detonated by humanity. There were two designs/styles of nuclear weapon in development at Los Alamos: a gun-type uranium bomb, and a plutonium implosion device. The confidence in the uranium bomb was high, so "Little Boy" was shipped off to the Pacific without ever being tested. The plutonium implosion device in Trinity, "Gadget", was detonated in the morning of July 16, and marked the beginning of the Nuclear Age. Oppenheimer later wrote that the experience reminded him of a quote from the Hindu holy text, the Bhagavad-Gita, the famous quote "Now I am become Death, the destroyer of worlds." The explosive force caused by Gadget was four times as much as had been predicted by everyone at Los Alamos.

• The name of the test comes from Holy Sonnet XIV, by John Donne

Source: Nobel Prize

Otto Hahn

Co-Discoverer of Nuclear Fission

Otto Hahn was born in Frankfurt in 1879. He studied Chemistry at Marburg and Munich. His work and studies were interrupted by World War I, but soon after he collaborated with Dr. Lise Meitner on work relating with artificial radioactivity. His most important contribution to science was in 1938, when he, Dr. Meitner, and Dr. Fritz Strassman discovered nuclear fission.

• Co-discoverer of Radioactivity

Source: The Nobel Prize

Glenn T. Seaborg

Glenn Theodore Seaborg, born in 1912 in Michigan, moved to California as a child and excelled academically, becoming valedictorian of his high school class. Joining UC Berkeley's faculty in 1939, he rose to become a professor and directed nuclear chemical research at Lawrence Radiation Laboratory. Seaborg served on the AEC's General Advisory Committee and was appointed Chancellor of UC Berkeley in 1958. During WWII, Seaborg led plutonium research at the Manhattan Project's Metallurgical Laboratory. He co-discovered plutonium and subsequent transuranium elements up to element 102, expanding the understanding of the Periodic Table.

• Won the Nobel Prize in Chemistry in 1951

Source: OSTI

Development of Thermonuclear Weapons

A thermonuclear weapon differs from the previously developed nuclear fission based weapons. A thermonuclear weapon is based on the concept of fusion, where they would "fuse" lighter elements. The design was deemed too impractical during the second World War, so it was practically shelved in favor of the fission-based method. Edward Teller was the primary supporter behind the thermonuclear bomb, termed the "Super". Oppenheimer allowed Teller to theorize and work on concepts for the Super, but it did ultimately not contribute to the development and testing of the fission based designs. After the war, the Soviets developed their own bomb, putting them on the same level as America. Desperate for an edge, Truman decided to accelerate development of the Super, which was getting less practical by the day. A newer approach for the Super was proposed by Teller and Stanislaw Ulam in 1951, and the first thermonuclear device waws detonated on November 1, 1952, exploding with the force of 700 Little Boys, the bomb dropped on Hiroshima.

• Ivy Mike, the first thermonuclear weapon detonated.

Source: OSTI

Chicago Pile 1

Chicago Pile 1 was the world's first nuclear reactor. It was constructed under the guidance of Enrico Fermi and achieved criticality on December 2, 1942. The reactor consisted of stacks of graphite blocks with uranium and uranium oxide fuel. The existence of CP-1 proved the feasibility of controlled nuclear fission, with General Leslie R. Groves saying it was the single most important scientific event in the history of atomic power.

• A drawing of CP-1

Source: Académie des sciences

Discovery of Radioactivity

Changes the World Forever

Radiation before the discovery of nuclear radiation was just light radiation, which was not well understood but described well thanks to Maxwell's theory. X-Rays were still mysterious, hence their name. Henri Becquerel presented an idea, that X-Rays might be a result of the fluorescence of the glass of the Crookes tube in which cathode rays were produced at low pressure.Becquerel devised an experiment to test his idea, realizing that the radiation he was observing was not light based, as the materials were opaque.

• Hans Becqurel, the discoverer of radiation

Source: OSTI

Surrender of Japan

Due to the rapid succession in which the atomic bombs had been deployed, Japan was under the impression that America could continually drop these devices on them until they either surrendered or were dead. Following the bombing of Hiroshima, Japanese leadership met and decided they would hold out and hope that they could win something more than a surrender from the Allies if they caused significant casualties from a land invasion. They met again following the bombing of Nagasaki and tied 3-3 on whether or not to surrender, a tie which the Emperor himself historically broke. Surrender was offered on August 10. Truman personally suspended atomic bombings while surrender was being discussed, and on August 12, the Allies formally accepted the surrender of Japan so long as the role of Emperor was purely ceremonial. The Japanese people learned of the surrender when American bombers dropped leaflets containing a translated response of America to Japan's surrender. Emperor Hirohito instructed the government to accept the terms in their entirety, not wishing to see his people suffer any longer. Loyalty to the emperor and the culturally ingrained belief to not surrender clashed, causing various military leaders to kill themselves to avoid choosing. Japan and America signed the Instrument of Surrender aboard the USS Missouri on September 2, 1945. Following the bombings, Truman authorized the creation of the Atomic Bomb Casualty Commission, who sent doctors to Japan to study the effects of radiation on victims of the bomb.

• General Douglas MacArthur signs the Instrument of Surrender aboard the USS Missouri

Source: Atomic Heritage Foundation

Fritz Strassmann

Father of the Nuclear Reactor

Fridrich Wilhem "Fritz" Strassman was born in 1902 in Germany. He joined Otto Hahn and Lise Meitner in their investigation of neutron bombardment of uranium. His Chemistry expertise contributed to the discovery of lighter elements produced from neutron bombardment. Ultimately his expertise in that area lead to the discovery of nuclear fission, and that that process could be used to create a weapon of mass destruction.

• Was on the Alsos List, the Manhattan Project's effort to monitor the German atomic program
• Concealed a Jewish friend in his apartment

Source: OSTI

Hans Bethe

Head of the Theoretical Division

Hans Bethe was born in Germany in 1906. In 1932, he accepted a professorship at Germany's University of Tubingen, of which he would be forced out of a year later due to Hitler's purge of civil-service employees. After World War II broke out in Europe, he considered a nuclear bomb impractical, later changing his mind due to Oppenheimer. Oppenheimer thought highly of Bethe, and chose Bethe to lead the Theoretical Division (T Division). Following the war, Bethe returned to Cornell and served as an advisor on nuclear reactors and weapons. He headed a National Security Council in the late 1950s to consider the feasibility of a treaty banning futher nuclear testing.

• Vocally opposed the revocation of Oppenheimer's clearance
• Refused to participate in the development of the thermonuclear bomb

Source: Los Alamos National Laboratory

Los Alamos National Laboratory

Los Alamos National Laboratory was the site for the development and testing of the atomic bomb. J. Robert Oppenheimer was the head of Los Alamos, and under his direction, it took just 27 months for the atomic bomb to developed, tested, and used. Los Alamos contained housing and facilities for their workers. Their efforts culminated in the Trinity Test 200 miles south of the laboratory.

• Los Alamos during the War
• It was called Los Alamos Laboratory during the war, and was reorganized into Los Alamos National Laboratory following the war

Source: Académie des sciences

Discovery of Alpha, Beta, and Gamma Rays

Ernest Rutherford discovered the separation of radiation through an experiment with radioactive decay. Alpha particles are stopped by a few centimeters of air, and have an electric charge. Beta particles are smaller, but move faster, and are still electrically charged. Gamma particles carry no charge and move incredibly fast. It is important to note that Gamma rays are the most deadly of these particles, as they can damage DNA and other crucial biological components. Alpha and Beta particles rarely, if ever, penetrate skin.

• How radiation is separated

The Most Important Thing in the History of the World

Source: National Park Service

The Manhattan Project

The Manhattan Project was the United States' secret project for developing nuclear weapons. There were three centers for the project. Hanford in Washington and Oak Ridge in Tennessee were dedicated to refining and enriching uranium, and producing plutonium. Los Alamos in New Mexico designed the nuclear weapons, and later built them. These efforts culminated in the Trinity test, the world's first nuclear detonation, and later, the bombings of Hiroshima and Nagasaki, the first and only instances of nuclear weaponry in warfare. Each center had housing and facilities. The Manhattan Project was eventually dissolved and all components were folded into the Atomic Energy Commission in 1946.

• The University of Chicago, while not an official part of the Manhattan Project, contributed greatly to the development of the Atomic Bomb

(It all goes downhill from here)

Source: OSTI

Atomic Fission

Nuclear fission, the process of splitting the atom, was discovered in Nazi Germany in 1938. Otto Hahn, Lise Meitner, and Fritz Strassman discovered fission while bombarding elements with neutrons in Berlin. Rather than changing, uranium nuclei split almost evenly into two radioactive barium isotopes. The loss of mass from the split was converted into heat energy. Another, more crucial discovery was that the process of splitting the atom caused extra neutrons to fly off, which could in turn hit other uranium atoms and cause more atoms to split and more neutrons to fly off and hit other atoms causing a chain reaction. This forms the basis for most nuclear reaction-based technology.

• The laboratory where fission was discovered, the Kaiser Wilhelm Institute for Chemistry in Berlin

Ahhh, Bikini Bottom

Source: Nuclear Princeton

Operation Crossroads

Operation Crossroads was a series of nuclear tests at Bikini Atoll for the purpose of gathering information about the effects of radiation on both technology and people. Ultimately, 67 nuclear tests were conducted in the area, including the detonation of Castle Bravo, the largest, most destructive bomb the US ever built. The inhabitants of the nearby islands had to relocate multiple times, and the islands are still uninhabited today. The chance of cancer was reported to be greater than 1/3 if you were exposed to fallout.

• The mushrrom cloud generated by a nuclear detonation.

Source: Atomic Archive

Edward Teller

Leper of Los Alamos

Edward Teller, born in Budapest in 1908, overcame a leg amputation from a streetcar accident to become a pivotal figure in 20th-century physics. He earned his Ph.D. under Werner Heisenberg in 1930. Fleeing Nazi Germany, he settled in the U.S., teaching at George Washington University. Teller's interests shifted to nuclear physics during WWII, contributing significantly to the Manhattan Project. The contentious Oppenheimer hearings in 1954 highlighted Teller's divergence from his peers, namely the fact that he directly stated he didn't have confidence in Oppenheimer. Despite criticism, he remained an ardent supporter of nuclear testing and the development of anti-ballistic missile systems.

• Spoke against Oppenheimer in his security clearance hearings
• Left Los Alamos due to his pursuit of the thermonuclear bomb

A Written Harbinger

Source: Atomic Heritage Foundation

Einstein-Szilard Letter

The Einstein-Szilard Letter was a letter written jointly by Leo Szilard and Albert Einstein outlining the dangers of the nuclear bomb to Franklin D. Roosevelt and what might happen if Germany were to develop it before the Allies. It urged Roosevelt to start the development of America's own atomic bomb. It also emphasized that America should use their nuclear technology for peaceful purposes and to maintain a strategic advantage over nuclear weapons. It was the catalyst for the Manhattan Project, and a crucial point in history.

• Albert Einstein and Leo Szilard writing the letter to FDR.

Source: The Nobel Prize

Enrico Fermi

Father of the Nuclear Reactor

Enrico Fermi was born in 1901. He obtained his Doctorate in Physics at 21 in 1922. In 1926, he discovered the statistical laws, now called the Fermi Statistics. Fermi's experiments earned him the distinction of being referred to as the greatest expert on neutrons. Following the discovery of fission, he directed a series of experiments which ultimaetly led to the world's first atomic pile. He contributed greatly to the Manhattan Project.

• Created the world's first moderated nuclear reaction.
• Referred to as the world's greatest expert on neutrons.

Source: Primary Connections

Start of the Atomic Model

Ernest Rutherford first described electrons around a nucleus in his model in 1911. Rutherford described the atom as having a tiny, dense, positively charged core called the nucleus. The electrons were negatively charged and orbiting around the nucleus. This model was eventually replaced by the Bohr atomic model created by Niels Bohr. Bohr postulated that the electrons did orbit, but the energy of the electron depended on the size of it's orbit. Energy would only be emitted if an electron dropped to a lower orbit.

• Rutherford's Model of the atom

Source: Office of the Historian

Formation of the United Nations

During World War II, key conferences and diplomatic efforts laid the groundwork for the establishment of the United Nations (UN). At the Quebec Conference in 1943, Cordell Hull and Anthony Eden discussed creating an international organization based on sovereign equality. This idea progressed through subsequent meetings, including the Moscow and Tehran Conferences, where Franklin D. Roosevelt proposed a structure with an assembly and an executive committee of "the four policemen" – the US, UK, USSR, and China – to enforce peace. Task-oriented organizations like the Food and Agricultural Organization and the UN Relief and Rehabilitation Administration were established to address urgent postwar needs. At Dumbarton Oaks in 1944, representatives drafted a charter emphasizing collective security, later refined at the Yalta Conference. The San Francisco Conference in 1945 finalized the UN Charter, creating the General Assembly, Security Council, Economic and Social Council, International Court of Justice, Trusteeship Council, and Secretariat. The Senate ratified the charter in 1945.

• The signing of the UN Charter

Source: Office of the Historian

Nuclear Non-Proliferation Treaty

The Nuclear Non-Proliferation Treaty was an attempt at regulating the growth and proliferation of nuclear weapons. The treaty, while unsuccessful, set a precedent for international cooperation because both nuclear and non-nuclear states agreed to prevent proliferation. The treaty itself was unsuccessful beacuse the US was intending to share nuclear technology with less advanced NATO members and resistance from non-nuclear states to limit their development.

• A picture of dignitaries signing the NPT in Moscow, Russia

Source: Technical University of Munich

Discovery of the Neutron

James Chadwick experimented with bombarding beryllium with alpha particles obtained from the radioactive decay of polonium. The resulting radiation almost fully penetrated a lead shield, something which the known particles at the time could not explain. The concept of a neutrally charged paticle with the same mass of a proton removed his problems, and later experiments confirmed the existence of the neutron.

• James Chadwick, the discoverer of the neutron

Source: National WWII Museum

Source: National WWII Museum

Atomic Bombings of Japan

Source: Nobel Prize

Niels Bohr

Founder of the Bohr Nuclear Model

Niels Bohr was born in Copenhagen in 1885. In 1911, he stayed at Cambridge and followed the work at the Cavendish Laboratory under Sir J.J. Thompson. He worked at Ernest Rutherford's laboratory in Manchester. His most important contribution to science was an updated, but still partly wrong model of the atom, which was further expanded by Werner Heisenberg in 1925.

• Creator of the Bohr Model

Source: Atomic Heritage Foundation

Entry of the USSR into the Nuclear Club

The Soviet atomic program was rather lackluster during the war until they learned of the American and German nuclear programs. In 1943, the project gained actual government funding and importance, but only had about 20 researchers and a handful of staff. Following Trinity, however, the development of the Soviet atomic bomb quickly increased. At the Potsdam Conference, Truman told Stalin of a "new weapon of unusual destructive force". While appearing unmoved, Stalin told his staff to get Kurchatov to work faster. The bombings of Hiroshima and Nagasaki only further escalated the program, which caused the creation of their version of Los Alamos, called Arzamas-16 and nicknamed "Los Arzamas". Their first nuclear chain reaction was on December 25, 1946, and they tested their first device, RDS-1, or "First Lightning", on August 29, 1949.

• Igor Kurchatov, essentially the Russian Oppenheimer

Source: US Army Corps of Engineers.

SM -1

SM-1 was the first nuclear reactor providing power to the national grid. It proved the feasibility of a nuclear reactor for commercial power generation. It also provided insights into the operation and feasibility of pressurized-water reactors. The reactor was decomissioned in 1973, and the site remained as a training facility until 2020. Now, America has 93 nuclear reactors hooked up to the national grid, powering millions of homes.

• SM-1 during the late 1960s

Guess who's coming for dinner?

Source: National WWII Musuem

Bombing of Pearl Harbor

Following the end of Japan's of isolationism, Japan began to advance technologically and culturally. This caused a rivalry to develop between Japan and America in the Pacific, later escalating a considerable amount with the annexation of Hawaii. In 1940, Roosevelt ordered the US Pacific Fleet to transfer from San Diego, California, to Pearl Harbor, Hawaii. Japan wanted to invade the undefended Allied colonies in Asia, which the US would disapprove of and enter the war to defend the colonies. Japan decided to gamble and bomb the fleet at Pearl Harbor so they could not intervene. Following the attack on Pearl Harbor, Japan attacked both European and US holdings in Asia. The US quickly thereafter entered World War II.

• The USS Virginia sinks in Pearl Harbor
• Following the attack, the Enterprise sailed into Pearl Harbor, and refueled and rearmed in a record seven hours.

Source: Center for Arms Control and Non-Proliferation

1983 Soviet False Alarm Incident

In a period of heightened tensions in the Cold War, a Soviet monitoring station detected an apparent American missile launch, and started preparing for retaliation. The station started preparing for a retaliatory strike, but something was off to Stanislav Petrov, an officer there and a contributing officer in the development of the early-warning software. First, it only "detected" one missile incoming, a tactical blunder as one missile would hardly affect the responsive ability of the Soviet military. Two, Petrov knew it was prone to error. Rather than alerting the chain of command or following procedure, he waited to see if any more evidence would come. Almost two weeks later, NATO conducted military exercises, which due to the events at the Soviet monitoring station, Moscow thought was real to a degree. It is likely the closest the world has come to nuclear annhiliation since the Cuban Missile Crisis.

• Stanislav Petrov, the Soviet officer responsible for saving the world

Source: Atomic Heritage Foundation

J. Robert Oppenheimer

Death, the Destroyer of Worlds

J. Robert Oppenheimer was an American theoretical physicist and is commonly referred to as the "father of the atomic bomb". While he was at UC Berkeley, he became involved in a communist organization. Later in 1942, he assembled a study group to examine the principles of nuclear bomb design. In October of 1942, General Leslie R. Groves asked Oppenheimer to head up Project Y in spite of his communist ties. After the bombing of Hiroshima and Nagasaki and the end of the war, he resigns as the director of the Los Alamos Laboratory and accepts a post at CalTech. Due to opposing the new H-Bomb concept and his previous communist ties, Oppenheimer's security clearance is removed to remove him as a voice in politics.

• Project Y is an alternative name for the work and research done at Los Alamos, including Los Alamos itself before being incorporated
• Continued to be a voice in the scientific community following his loss of clearance, opposing nuclear proliferation

Source: Smithsonian Magazine

Potential Escalation of the Korean War

In an effort to end the Korean War, the US placed bombers in strategic locations as a bluff, an action which did not impress the Chinese, who entered the war in 1950. In a surprising show of force, nine fissile cores of the bombs were transported to Okinawa to be installed in the bomb casings. The war had ended by then, so no bombs were used, and the planes with the bombs flew home.

• B-29 Bombs had to be specially modified to carry the bombs.

Source: US Nuclear Regulatory Commission

Three Mile Island Accident

The Three Mile Island Accident was a minor meltdown of the Unit 2 Reactor at the The Misle Island nuclear power plant. While there was little to no effect on the health of people, it contributed to the public opinion of nuclear reactors, the opinion being that they are typically dangerous. The accident also contributed to better safety measures and procedures. The reactor itself is permanently shut down today.

• A picture of the facility at Three Misle Island

Source: Nobel Prize

Marie Curie

Proponent of Radioactivity

Marie Sklodowska, was born in Warsaw in 1867. She moved to Paris and studied at the Sorbonne, obtaining a Licenciateship in Physics and Mathematical Sciences, and meeting and later marrying Pierre Curie. After Henri Becquerel discovered radioactivity in 1896, this inspired both Pierre and Marie to investigate the potential for different materials to be radioactive, like radium.

• Furthered general understanding of radioactivity
• First woman to be Professor of General Physics at the Sorbonne.

Source: Live Science

Concept of Mutually Assured Destruction

Mutually assured destruction is a concept where should a nation launch nuclear missiles at another, that nation would launch their missiles as well, resulting in mutual annhiliation. In the context of the mid-20th century, mutually assured destruction was synonymous with the collapse of civilization, as even if one member of one side launched their missiles, one or more of the other side would, leading to the other members of the initial side launching their missiles, causing worldwide mutual destruction.

• A US nuclear missile in it's silo.

Russian Theoretical Physicist

Source: The Nobel Prize

Andrei Sakharov

Andrei Sakharov was born in Russia in 1921. He was talented in Theoretical Physics at an early age, and got a doctorate in 1945. Working under Igor Tamm, he worked on the Soviet Hydrogen Bomb program. Sakharov was deeply patriotic and wanted to break the monopoly the Americans had on nuclear weapons. He later changed his stance and expressed warnings against the arms race, and criticized Soviet society, leading to his awarding of the Peace Prize, which he could not attend due to the Soviet government prohibiting him from leaving the country. His wife attended in his stead.

• Won the Nobel Peace Prize in 1975, but was unable to travel due to the Soviet government.
• He and his wife were kept under strict surveilance until 1985

Source: National Park Service

Hanford Site

The Hanford site was constructed along the Columbia River due to access to cold water to cool the reactors, hydroelectric power, distance from population centers, and excellent transportation facilities. Hanford would produce the plutonium that was used in Trinity and the bomb dropped on Nagasaki.

• The Hanford Site under construction

It's the end of the world as we know it

Source: Office of the Historian

Cuban Missile Crisis

Following the failed US attempt to overthrow the Castro regime in Cuba, Khrushchev and Castro met and agreed to place Soviet nuclear missiles in Cuba as a deterrent from future intervention attempts. It wasn't a greatly kept secret as various recon flights discovered the presence of a Soviet arms build-up on Cuba. Kennedy issued a general warning against the introduction of weapons to Cuba. On October 14, a U-2 spyplane took aerial photographs of nuclear missile launch sites under construction. In response to the photographs, the US "quarantined" Cuba navally. A quarantine is separate from a blockade, which occurs during conflict, while a quarantine enables the US to recieve support from the Organization of American States. Kennedy sent Khrushchev a letter saying the US would not permit weapons to be delivered to Cuba, and demanded the dismantling of the missile bases. Further recon flights showed the sites were nearing completion, and US forces were placed at DEFCON 2. Eventually, an agreement was reached where the Soviet Union would remove the missiles from Cuba and the US would remove their missiles from Turkey. The latter stipulation was suggested by Khrushchev in a series of messages between him and Kennedy.

• A photograph from a spyplane showing a nuclear missile launch site under construction in Cuba

Source: Department of Energy

Formation of the Atomic Energy Commission

The Manhattan Project was dissolved and reintegrated into the Atomic Energy Commission, which was organized to control and regulate the atomic energy and weaponry of America. The Atomic Energy Act of 1954 led to the opening of atomic power for commercial use and gave the AEC authority to regulate the industry. The AEC was dedicated towards the development and use of atomic power for peaceful purposes, which was shown in the construction of the world's first full scale nuclear power plant in Pennsylvania.

• The Seal of the AEC

Source: National Archives

Intermediate-Range Nuclear Forces Treaty

The INF Treaty was an effort at reducing tensions between the US and the USSR at the height of the Cold War. Under the treaty, both sides agreed to dismantle their short to medium range weapons and stop producing those weapons. The treaty included provisions for monitoring and compliance with the treaty. It considerably reduced tensions in the Cold War and is commonly attributed as one of the primary causes of the end of the Cold War.

• Ronald Reagan and Mikhail Gorbachev sign the INF Treaty

Source: US Nuclear Regulatory Commission

Chernobyl Accident

The Chernobyl Accident is the single largest nuclear disaster in human history. It irradiated 30 kilometers in every direction from the plant and displaced 335,000 people, and affecting almost one million total people. It was caused due to worker error and design fault, both of which were easily preventable in the circumstances. There are long term effects both on the health of people affected and on the environment. A sarcophagus was built to contain the radiation still being emitted by the exposed core, with a newer containment building being built and finished in 2017. This incident is also likely a scare factor in the public opinion of nuclear reactors.

• A picture of Reactor #3 after the meltdown

Source: Gerald R. Ford Presidential Library and Museum

Strategic Arms Limitation Talks

The Strategic Arms Limitation Talks or SALT were treaties and conferences aimed at reducing the amount of long-range missiles that each side had in their arsenal. SALT 1 was signed in 1972 and was set to expire in five years. SALT 2 was created with the intent of being permanent and larger in it's scope of what it prevented. The stipulations of SALT 2 consisted of a ban on ICBMs and a limit on the amount of vehicles that could carry nuclear weapons as well as limiting the amount of missiles that could have more than one warhead. While the treaty was never ratified by the US Senate, both countries stood by the terms until it's expiration in 1985.

• A picture showing a meeting between Gerald R. Ford and his advisors over a note received from Leonid Brezhnev about SALT

Source: Famous Scientists

Henri Becquerel

Discoverer of Radioactivity

Antoine Henri Becquerel was born in Paris in 1852. Becqurel's family consisted of scholars and scientists of distinguished standing. He would begin an investigation into a potential connection between X-Rays and naturally occuring phosphorescence in 1892, leading to the discovery of radioactivity in 1896.

• Discoverer of Radioactivity
• Professor of Applied Physics at Paris Museum

Source: Atomic Heritage Foundation

Leslie R. Groves

They made him a General.

Leslie Groves was an officer of the US Army Corps of Engineers. He was appointed to lead the Manhattan Project as a temporary Brigadier General. He directed atomic research to be conducted at Columbia University and the University of Chicago. He selected J. Robert Oppenheimer personally, regardless of his Communist associations, also waiving the process for his security clearance. Groves was described as critical and stubborn, but was intellgent and driven to achieve the goals given to him at any cost. Colonel Kenneth D. Nichols describes him as abrasive, but ultimately states that Groves was the right choice for the job and would pick him again and again.

• Leader of the Manhattan Project

Source: Office of the Historian

Dissolution of the Soviet Union

The Dissolution of the USSR was not an overnight event but rather was built up to over the course of the 1980s-1990s. Gorbachev began a process of Democratization, such as loosening the hold the USSR had on the Eastern European countries, allowing for a multi-party system, and creating a presidency. These actions caused internal political dissention in the USSR. The Baltic states demanded independence, and a coup was attempted in August 1991. Following the coup, the Baltic states and Ukraine declared independence. Boris Yeltsin, the primary democracy-oriented political figure in the USSR, met with the seceeding states and formed the Commonwealth of Independent States, which signaled the end of the Soviet Union. On December 25, 1991, the Soviet flag was lowered above the Kremlin, and replaced by the current Russian flag. Gorbachev had resigned that day, leaving Yeltsin as the new president.

• Two pictures showing the change of the flag above the Kremlin, signaling the end of the USSR
• Gorbachev attributed the Chernobyl Accident as one of the causes of the collapse of the USSR