Antarctica

The name given to the continent originates from the word antarctic, which comes from Middle French antartique or antarctique ('opposite to the Arctic') and, in turn, the Latin antarcticus ('opposite to the north'). Antarcticus is derived from the Greek ἀντι- ('anti-') and ἀρκτικός (arktikos, 'of the Bear [Ursa Major], northern'). The Greek philosopher Aristotle wrote in Meteorology about an "Antarctic region" in c. 350 BC. The Greek geographer Marinus of Tyre reportedly used the name in his world map from the second century AD, now lost. The Roman authors Gaius Julius Hyginus and Apuleius used for the South Pole the romanised Greek name polus antarcticus, from which derived the Old French pole antartike (modern pôle antarctique) attested in 1270, and from there the Middle English pol antartik, found first in a treatise written by the English author Geoffrey Chaucer. …

From the end of the Neoproterozoic era to the Cretaceous, Antarctica was part of the supercontinent Gondwana. Modern Antarctica was formed as Gondwana gradually broke apart beginning around 183 Ma. For a large proportion of the Phanerozoic, Antarctica had a tropical or temperate climate, and it was covered in forests. During the Cambrian period, Gondwana had a mild climate. West Antarctica was partially in the Northern Hemisphere, and during the time, large amounts of sandstones, limestones, and shales were deposited. East Antarctica was at the equator, where seafloor invertebrates and trilobites flourished in the tropical seas. By the start of the Devonian period (416 Ma), Gondwana was in more southern latitudes, and the climate was cooler, though fossils of land plants are known from then. Sand and silts were laid down in what is now the Ellsworth, Horlick, and Pensacola Mountains. …

Positioned asymmetrically around the South Pole and largely south of the Antarctic Circle (one of the five major circles of latitude that mark maps of the world), Antarctica is surrounded by the Southern Ocean. Rivers exist in Antarctica; the longest is the Onyx. Antarctica covers more than 14.2 million km2 (5,500,000 sq mi), almost double the area of Australia, making it the fifth-largest continent, and comparable to the surface area of Pluto. Its coastline is almost 18,000 km (11,200 mi) long: as of 1983, of the four coastal types, 44% of the coast is floating ice in the form of an ice shelf, 38% consists of ice walls that rest on rock, 13% is ice streams or the edge of glaciers, and the remaining 5% is exposed rock. The lakes that lie at the base of the continental ice sheet occur mainly in the McMurdo Dry Valleys or various oases. …