- published: 26 May 2015
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The explosive yield of a nuclear weapon is the amount of energy discharged when a nuclear weapon is detonated, expressed usually in the equivalent mass of trinitrotoluene (TNT), either in kilotons (thousands of tons of TNT) or megatons (millions of tons of TNT), but sometimes also in terajoules (1 kiloton of TNT = 4.184 TJ). Because the precise amount of energy released by TNT is and was subject to measurement uncertainties, especially at the dawn of the nuclear age, the accepted convention is that one kt of TNT is simply defined to be 1012calories equivalent, this being very roughly equal to the energy yield of 1,000 tons of TNT.
The yield-to-weight ratio is the amount of weapon yield compared to the mass of the weapon. The theoretical maximum yield-to-weight ratio for fission weapons (thermonuclear weapons) is 6 megatons of TNT per metric ton of bomb mass (25 TJ/kg). Yields of 5.2 megatons/ton and higher have been reported for large weapons constructed for single-warhead use in the early 1960s. Since this time, the smaller warheads needed to achieve the increased net damage efficiency (bomb damage/bomb weight) of multiple warhead systems, has resulted in decreases in the yield/weight ratio for single modern warheads.
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission ("atomic") bomb test released the same amount of energy as approximately 20,000 tons of TNT. The first thermonuclear ("hydrogen") bomb test released the same amount of energy as approximately 10,000,000 tons of TNT.
A modern thermonuclear weapon weighing little more than 2,400 pounds (1,100 kg) can produce an explosive force comparable to the detonation of more than 1.2 million tons (1.1 million tonnes) of TNT. Thus, even a small nuclear device no larger than traditional bombs can devastate an entire city by blast, fire and radiation. Nuclear weapons are considered weapons of mass destruction, and their use and control have been a major focus of international relations policy since their debut.
Only two nuclear weapons have been used in the course of warfare, both by the United States near the end of World War II. On 6 August 1945, a uranium gun-type device code-named "Little Boy" was detonated over the Japanese city of Hiroshima. Three days later, on 9 August, a plutonium implosion-type device code-named "Fat Man" was exploded over Nagasaki, Japan. These two bombings resulted in the deaths of approximately 200,000 Japanese people—mostly civilians—from acute injuries sustained from the explosions. The role of the bombings in Japan's surrender, and their ethical status, remain the subject of scholarly and popular debate.
David "Davy" Crockett (August 17, 1786 – March 6, 1836) was a celebrated 19th century American folk hero, frontiersman, soldier and politician. He is commonly referred to in popular culture by the epithet "King of the Wild Frontier". He represented Tennessee in the U.S. House of Representatives, served in the Texas Revolution, and died at the Battle of the Alamo.
Crockett grew up in East Tennessee, where he gained a reputation for hunting and storytelling. After being elected to the rank of colonel in the militia of Lawrence County, Tennessee, he was elected to the Tennessee state legislature in 1821. In 1826, Crockett was elected to the U.S. House of Representatives. Congressman Crockett vehemently opposed many of the policies of President Andrew Jackson, most notably the Indian Removal Act. Crockett's opposition to Jackson's policies led to his defeat in the 1834 elections, prompting his angry departure to Texas shortly thereafter. In early 1836, Crockett took part in the Texas Revolution and was killed at the Battle of the Alamo in March.