Antarctica is the Earth's southernmost continent, underlying the 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 14.0 million km2 (5.4 million sq mi), it is the fifth-largest continent in area after Asia, Africa, North America, and South America. About 98% of Antarctica is covered by ice, which averages at least 1.6 kilometres (1.0 mi) in thickness.
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 inches) along the coast and far less inland. 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. Only cold-adapted plants and animals survive there, including penguins, seals, nematodes, tardigrades, mites, many types of algae and other microorganisms, and tundra vegetation.
Although myths and speculation about a Terra Australis ("Southern Land") date back to antiquity, the first confirmed sighting of the continent is commonly accepted to have occurred in 1820 by the Russian expedition of Mikhail Lazarev and Fabian Gottlieb von Bellingshausen. The continent, however, remained largely neglected for the rest of the 19th century because of its hostile environment, lack of resources, and isolation. The first formal use of the name "Antarctica" as a continental name in the 1890s is attributed to the Scottish cartographer John George Bartholomew.
The Antarctic Treaty was signed in 1959 by twelve countries. To date, forty-six countries have signed the treaty. The treaty prohibits military activities and mineral mining, supports scientific research, and protects the continent's ecozone. Ongoing experiments are conducted by more than 4,000 scientists of many nationalities and with various research interests.
Antarctica’s native land animals are all small invertebrates. They include mites, lice, springtails, midges and fleas, many of which are parasites of seals and birds. The largest animal that permanently dwells on land in Antarctica is a wingless midge that grows to just over 1cm long.Only a few bird species breed in Antarctica, among them are penguin specie, snow petrels, Antarctic petrels and South Polar skuas. Approximately 45 species of birds breed south of the Antarctic Convergence.Compared to Antarctica’s relative barrenness, the Southern Ocean teems with life. With krill as the basis of its food web, the Southern Ocean supports a wealth of fish, seal, whale and seabird species. Of greatest interest among Antarctica’s marine life are the marine mammals: whales and seals.While wildlife may not seem to be concerned about your presence you may in fact be causing it considerable stress. A single thoughtless gesture can cause the loss of an egg or chick to a predator, or the crushing of a seal pup by a frightened adult.
Around 200 million years ago, Antarctica was joined with Australia, Africa, South America, India and New Zealand in the supercontinent Gondwana. Ten million years later, the continents, subcontinent and islands began moving into their present positions. By about 70 million years ago, the continents were becoming widely separated and what is now known as the Drake Passage opened. After making its final detachment from the Australian continent, about 40 million years ago, Antarctica settled into its present polar position and began to cool dramatically.
November is early summer: the spring pack ice is breaking up, and birds – especially penguins – are courting and mating. December and January, when penguins are hatching eggs and feeding chicks, are the height of the austral summer, bringing warmer temperatures and up to 20 hours of sunlight every day. In the late summer months of February and March, whale-watching is at its best, penguin chicks are beginning to fledge and adult penguins are ashore molting.During winter the pack ice extends its frozen mantle for 1000km around most of the continent. It is extremely cold with temperatures plummeting to -50°C and near round-the-clock darkness.
Antarctica is surrounded by the Southern Ocean which is formed by the southern parts of the Atlantic, Indian and Pacific Oceans. The geography of Antarctica is dominated by its south polar location and, thus, by ice. The Antarctic continent is centered asymmetrically around the South Pole and largely south of the Antarctic Circle. Some 98% of Antarctica is covered by the Antarctic ice sheet, the world's largest ice sheet and also its largest reservoir of fresh water.There are four volcanoes on the mainland of Antarctica: Mt. Melbourne, Mt. Berlin, Mt. Kauffman and Mt. Hampton.