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.
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Today's selected anniversaries:
British authorities arrested the conspirators of the Cato Street
Conspiracy, an attempt to murder Prime Minister Lord Liverpool and all
the British cabinet ministers.
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.
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.
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.
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repealed less than one year later.
Wiktionary's word of the day:
A tropical Indian fig tree, Ficus bengalensis, that has many aerial
Wikiquote quote of the day:
There is but one coward on earth, and that is the coward that dare not
--W. E. B. Du Bois
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