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Antarctica (US English , UK English or and or ) is Earth's southernmost continent, containing the geographic South Pole. It is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At , it is the fifth-largest continent in area after Asia, Africa, North America, and South America. For comparison, Antarctica is nearly twice the size of Australia. About 98% of Antarctica is covered by ice that averages in thickness, which extends to all but the northernmost reaches of the Antarctic Peninsula. Antarctica, on average, is the coldest, driest, and windiest continent, and has the highest average elevation of all the continents. Antarctica is considered a desert, with annual precipitation of only 200 mm (8 in) along the coast and far less inland. The temperature in Antarctica has reached −89 °C (−129 °F), though the average for the third quarter (the coldest part of the year) is −63 °C (−81 °F). There are no permanent human residents, but anywhere from 1,000 to 5,000 people reside throughout the year at the research stations scattered across the continent. Organisms native to Antarctica include many types of algae, bacteria, fungi, plants, protista, and certain animals, such as mites, nematodes, penguins, seals and tardigrades. Vegetation, where it occurs, is tundra. Although myths and speculation about a ''Terra Australis'' ("Southern Land") date back to antiquity, the Russian expedition of Fabian Gottlieb von Bellingshausen and Mikhail Lazarev on ''Vostok'' and ''Mirny'' first sighted a continental ice shelf in 1820. The continent, however, remained largely neglected for the rest of the 19th century because of its hostile environment, lack of resources, and isolation. Antarctica is a ''de facto'' condominium, governed by parties to the Antarctic Treaty System that have consulting status. Twelve countries signed the Antarctic Treaty in 1959, and thirty-eight have signed it since then. The treaty prohibits military activities and mineral mining, prohibits nuclear explosions and nuclear waste disposal, supports scientific research, and protects the continent's ecozone. Ongoing experiments are conducted by more than 4,000 scientists from many nations. ==Etymology== The name ''Antarctica'' is the romanized version of the Greek compound word ''ἀνταρκτική'' (''antarktiké''), feminine of ''ἀνταρκτικός'' (''antarktikos''), meaning "opposite to the Arctic", "opposite to the north". Aristotle wrote in his book ''Meteorology'' about an ''Antarctic region'' in c. 350 B.C.〔Aristotle. (Meteorologica. ) Book II, Part 5. 350 BC. Translated by E. Webster. Oxford: Clarendon Press, 1923. 140 pp.〕 Marinus of Tyre reportedly used the name in his unpreserved world map from the 2nd century A.D. The Roman authors Hyginus and Apuleius (1-2 centuries A.D.) used for the South Pole the romanized Greek name ''polus antarcticus,''〔Hyginus. (De astronomia. ) Ed. G. Viré. Stuttgart: Teubner, 1992. 176 pp.〕〔Apuleii. (Opera omnia. ) Volumen tertium. London: Valpy, 1825. 544 pp.〕 from which derived the Old French ''pole antartike'' (modern ''pôle antarctique'') attested in 1270, and from there the Middle English ''pol antartik'' in a 1391 technical treatise by Geoffrey Chaucer (modern ''Antarctic Pole'').〔G. Chaucer. (A Treatise on the Astrolabe. ) Approx. 1391. Ed. W. Skeat. London: N. Trübner, 1872. 188 pp.〕 Before acquiring its present geographical connotations, the term was used for other locations that could be defined as "opposite to the north". For example, the short-lived French colony established in Brazil in the 16th century was called "France Antarctique". The first formal use of the name "Antarctica" as a continental name in the 1890s is attributed to the Scottish cartographer John George Bartholomew.〔John George Bartholomew and the naming of Antarctica, CAIRT Issue 13, National Library of Scotland, July 2008, ISSN 1477-4186, and also 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Antarctica」の詳細全文を読む スポンサード リンク
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