Thorium is a chemical element with symbol Th and atomic number 90. A
reactive actinide metal, its chemistry is dominated by the +4 oxidation
state; it is silvery and tarnishes black in air, forming the dioxide. It
is malleable and moderately hard, with a high melting point. Its most
stable isotope, 232Th, is weakly radioactive with a half-life of
14.05 billion years, roughly the age of the universe: it decays very
slowly to stable lead. Thorium and uranium are the only two
significantly radioactive primordial elements. Thorium is chiefly
refined from monazite sands as a byproduct of extracting rare earth
metals. It was discovered in 1829 by the Norwegian mineralogist Morten
Thrane Esmark and identified by the Swedish chemist Jöns Jacob
Berzelius, who named it after Thor, the Norse god of thunder.
Applications were found for the element in the 19th century, but after
its radioactivity was discovered in the early 20th century, its use
significantly declined. Thorium has been suggested as a replacement for
uranium in nuclear reactors.
Today’s selected anniversaries:
Roman emperor Julian and his army set out from Antioch to attack
the Sassanian Empire.
The First Anglo-Burmese War, the longest and most expensive war
in British Indian history, began.
The Gloster Meteor, the first operational jet fighter for the
Allied Powers, made its maiden flight.
Country music stars Patsy Cline, Cowboy Copas, and Hawkshaw
Hawkins were killed when their Piper PA-24 Comanche crashed shortly
after takeoff in Camden, Tennessee, U.S.
The ZX81, a pioneering British home computer, was launched by
Sinclair Research and went on to sell over 1.5 million units around the
Wiktionary’s word of the day:
1. (obsolete) Doomed; lost.
2. (archaic) Abandoned, forlorn, lonely.
Wikiquote quote of the day:
War unleashes — at the same time as the reactionary forces of
the capitalist world — the generating forces of social revolution
which ferment in its depths.
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