Plutonium is a rare transuranic radioactive element. It is a radiological poison that accumulates in bone marrow, although its overall toxicity is sometimes overstated. The most important isotope of plutonium is plutonium-239, which is fissile, meaning Pu-239 atoms inside a critical mass of the isotope can break apart relatively easily and release a great deal of energy and more neutrons to sustain a nuclear chain reaction. This property makes it useful in nuclear weapons and in some nuclear reactors. The discovery of plutonium by a team led by Glenn T. Seaborg in 1940 became a classified part of the Manhattan Project to build an atomic bomb during World War II. The first nuclear test, "Trinity" (July 1945) and the atomic bomb used to destroy Nagasaki, Japan in August 1945, "Fat Man", both had cores of Pu-239. Disposal of plutonium waste from nuclear power plants and dismantled nuclear weapons built during the Cold War is a major concern. Most plutonium in the environment is from the fallout from above-ground nuclear tests and from several nuclear accidents.
Read the rest of this article: http://en.wikipedia.org/wiki/Plutonium
_______________________________ Today's selected anniversaries:
1820:
British authorities arrested the conspirators of the Cato Street Conspiracy, an attempt to murder Prime Minister Lord Liverpool and all the British cabinet ministers. http://en.wikipedia.org/wiki/Cato_Street_Conspiracy
1903:
The Cuban-American Treaty was finalized, allowing the United States to perpetually lease Guantánamo Bay from Cuba for the purposes of operating coaling and naval stations. http://en.wikipedia.org/wiki/Guant%C3%A1namo_Bay
1909:
The Silver Dart was flown off the ice of Baddeck Bay, a sub-basin of Bras d'Or Lake on Cape Breton Island, making it the first controlled powered flight in Canada and the British Empire. http://en.wikipedia.org/wiki/AEA_Silver_Dart
1945:
American photographer Joe Rosenthal took the Pulitzer Prize-winning photograph Raising the Flag on Iwo Jima during the Battle of Iwo Jima in World War II, an image that was later reproduced as the U.S. Marine Corps War Memorial. http://en.wikipedia.org/wiki/Raising_the_Flag_on_Iwo_Jima
2005:
The controversial French law on colonialism, requiring lycée teachers to teach their students "the positive role" of French colonialism, was passed, creating so much public uproar and opposition that it was repealed less than one year later. http://en.wikipedia.org/wiki/French_law_on_colonialism
_____________________________ Wiktionary's word of the day:
banyan (n): A tropical Indian fig tree, Ficus bengalensis, that has many aerial roots http://en.wiktionary.org/wiki/banyan
___________________________ Wikiquote quote of the day:
There is but one coward on earth, and that is the coward that dare not know. --W. E. B. Du Bois http://en.wikiquote.org/wiki/W._E._B._Du_Bois