Niels Bohr presents his “Open Letter to the United Nations.” As early as 1944, Bohr had recognized that the creation of atomic weapons would completely change the nature of future warfare. Bohr stressed the free exchange of scientific and technological information as critical to creating the basis for peaceful cooperation between nations, and reflected on the "hopes and the dangers" of the Atomic Age.
1950 to 1959: The Two Superpowers
1950 to 1959: The Two Superpowers
The United States conducts the Shot Dona Ana nuclear test at the Nevada Test Site on October 16, 1958. It was part of the Operation Hardtack II series, in which the United States conducted 37 nuclear tests. It which yielded a relatively small 37 tons.
The "Oak" nuclear test is conducted by the United States on June 28, 1958 at Enewetak Atoll in the Marshall Islands. It was part of the Operation Hardtack I series. The Oak Shot, conducted on a barge, yielded nearly 9 megatons, making it the 6th largest U.S. nuclear test.
The United States conducts the Coulomb-C Shot safety test on December 6, 1957 at the Nevada Test Site. The test yielded an unexpectedly high amount of 500 tons, leading to public concern over nuclear fallout.
The United States conducts the Coulomb-B Shot safety test during Operation Plumbbob, a controversial series of 29 nuclear tests held at the Nevada Test Site. Detonated on September 6, 1957, Coulomb-B was intended to make sure that an accidental detonation of conventional high explosives in a nuclear device would not cause a nuclear reaction.
The United States conducts the Shot Kepler nuclear test on July 24, 1957. It was the seventh of 29 nuclear tests conducted at the Nevada Test Site in 1957 as part of Operation Plumbbob. "Kepler" yielded 10 kilotons and was intended to test a ICBM warhead.
The United States conducts Shot Priscilla on June 24, 1957. It was the third of 29 nuclear tests conducted at the Nevada Test Site in 1957 as part of Operation Plumbbob. "Priscilla" yielded 37 kilotons. Operation Plumbbob was the longest, most comprehensive test series in the continental United States and became controversial after much of the operation was declassified. Plumbbob released approximately 58,300 kilocuries of radioiodine (I-131) into the atmosphere over a four month period, producing about 32% of all civilian exposure due to continental nuclear tests.
The United States conducts Shot Hornet at the Nevada Test Site on March 12, 1955. It was the fifth of 14 tests in the Operation Teapot nuclear test series. Operation Teapot was designed to test new kinds of fission devices. This test yielded 4 kilotons.
The United States conducts the "Simon" test on April 25, 1953. It was the 7th nuclear detonation in the Operation Upshot-Knothole test series at the Nevada Test Site. It yielded 43 kilotons.
The United States conducts the "Harry" test on May 19, 1953. It was the 9th nuclear detonation in the Operation Upshot-Knothole test series at the Nevada Test Site. Shot Harry yielded 32 kilotons, and was the most efficient pure fission device ever detonated with a yield under 100 kt. Due to an unexpected change in the wind, "Harry" caused the highest amount of radioactive fallout of any test in the continental United States, contaminating the city of St. George, Utah. The test was later called "Dirty Harry."