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Although myths and speculation about a '' Terra Australis '' ("Southern Land") go back to antiquity, the first sighting of the continent is commonly accepted to have occurred in 1821 by the Russia n expedition of Mikhail Lazarev and Fabian Gottlieb Von Bellingshausen . The continent was largely neglected in the 19th century because of its hostile environment, lack of resources, and isolated location. Antarctica is not under the political Sovereignty of any nation, although seven countries ( Argentina , Australia , Chile , France , New Zealand , Norway and the United Kingdom ) maintain Territorial Claims . Most other countries do not recognize these claims, and the claims of Argentina, Chile and the United Kingdom all overlap. Also, the United States and Russia reserve the right to territorial claims. Human activity on the continent is regulated by the Antarctic Treaty , which was signed in 1959 by 12 countries and prohibits any military activity, supports scientific research, and protects the continent's Ecozone . Ongoing experiments are conducted by more than 4000 scientists of many different nationalities and with many different research interests. Exploration Museum]] See Also: History of Antarctica Belief in the existence of a ''Terra Australis''—a vast continent located in the far south of the globe to "balance" the northern lands of Europe, Asia and north Africa—had existed since Ptolemy suggested the idea in order to preserve Symmetry of Landmass in the world. Depictions of a large southern landmass were common in maps such as the early 16th century Turkish Piri Reis Map . Even in the late 17th century, after explorers had found that South America and Australia were not part of "Antarctica," geographers believed that the continent was much larger than its actual size. However, as Antarctica has no indigenous population, it was mostly unknown and unexplored until the 19th Century . In 1841, explorer 2006 . 's Imperial Trans-Antarctic Expedition in 1914.]] During an 2006 . 2006 . Geography See Also: Geography of Antarctica The continent of Antarctica is located mostly south of the Antarctic Circle , surrounded by the Southern Ocean . It is the southernmost Land Mass and comprises more than 14 million km&2, making it the fifth-largest continent. The coastline measures 17 968 km (11,160 miles) and is mostly characterized by ice formations, as the following table shows: Physically, it is divided in two by the Transantarctic Mountains close to the neck between the Ross Sea and the Weddell Sea . The portion west of the Weddell Sea and east of the Ross Sea is called Western Antarctica and the remainder Eastern Antarctica , because they correspond roughly to the Eastern and Western Hemispheres relative to the Greenwich Meridian . About 98% of Antarctica is covered by the 2006 . Western Antarctica is covered by the West Antarctic Ice Sheet . The West Antarctic Ice Sheet has been of recent concern because of the possibility, real though small, of its collapse. If it does break down, Ocean Levels would rise by several meters in a relatively short period of time. Several Antarctic Ice Stream s, which account for about 10% of the ice sheet, flow to one of the many Antarctic Ice Shelves . , an active volcano on Ross Island .]] 2006 Antarctica is home to more than 70 2006 . See Also: Extreme points of Antarctica Antarctic territories Geology Geological history and paleontology More than 170 million years ago, Antarctica was part of the Supercontinent Gondwana . Over time Gondwana broke apart and Antarctica as we know it today was formed around 25 million years ago. Paleozoic era (540-250 Mya ) Mesozoic era (250-65 Mya) As a result of continued warming, the polar ice caps melted and much of Gondwana became a desert. In East Antarctica the Seed Fern became established, and large amounts of sandstones and shales were laid down at this time. The Antarctic Peninsula began to form during the Jurassic period (206-146 Mya), and islands gradually rose out of the ocean. Ginkgo trees and Cycad s were plentiful during this period, as were reptiles such as '' Lystrosaurus ''. In West Antarctica Conifer Forest s dominated through the entire Cretaceous period (146-65 Mya), though Southern Beech began to take over at the end of this period. Ammonite s were common in the seas around Antarctica, and dinosaurs were also present, though only two Antarctic dinosaur species ('' Cryolophosaurus '' and '' Antarctopelta '') have been described to date. It was during this period that Gondwana began to break up. Gondwana breakup (160-23 Mya) Geology of present-day Antarctica The geological study of Antarctica has been greatly hindered by the fact that nearly all of the continent is permanently covered with a thick layer of ice. However, newer techniques such as Remote Sensing have begun to reveal the structures beneath the ice. West Antarctica closely resembles the Andes of South America . The Antarctic Peninsula was formed by uplift and Metamorphism of sea-bed sediments during the late Paleozoic and the early Mesozoic eras. This sediment uplift was accompanied by Igneous intrusions and Volcanism . The most common rocks in West Antarctica are Andesite and Rhyolite volcanics formed during the Jurassic Period. There is also evidence of volcanic activity, even after the ice sheet had formed, in Marie Byrd Land and Alexander Island . The only anomalous area of West Antarctica is the Ellsworth Mountains region, where the Stratigraphy is more similar to the eastern part of the continent. East Antarctica is geologically very old, dating from the Precambrian era, with some rocks formed more than 3 billion years ago. It is composed of a Metamorphic and Igneous platform which is the basis of the Continental Shield . On top of this base are various more modern rocks, such as Sandstone s, Limestone s, coal and Shale s laid down during the Devonian and Jurassic periods to form the Transantarctic Mountains . In coastal areas some Faulting has occurred, for example in the Shackleton Range and in Victoria Land . The main Mineral resource known on the continent is Coal . It was first recorded near the Beardmore Glacier by Frank Wild on the Nimrod Expedition , and now low-grade coal is known across many parts of the Transantarctic Mountains. The Prince Charles Mountains contain significant deposits of Iron Ore . The most valuable resources of Antarctica lie offshore, namely the Oil and Natural Gas Field s found in the Ross Sea in 1973. Exploitation of all mineral resources is banned until 2048 by the Protocol On Environmental Protection To The Antarctic Treaty . Climate See Also: Climate of Antarctica covering Lake Fryxell , in the Transantarctic Mountains , comes from Glacial meltwater from the Canada Glacier and other smaller glaciers.]] Antarctica is the coldest place on Earth. It has little 2006 . Eastern Antarctica is colder than its western counterpart because of its higher elevation. Weather Front s rarely penetrate far into the continent, leaving the center cold and dry. Despite the lack of precipitation over the central portion of the continent, Ice there lasts for extended time periods. Heavy snowfalls are not uncommon on the coastal portion of the continent, where snowfalls of up to 1.22 meters (48 inches) in 48 hours have been recorded. At the edge of the continent, strong Katabatic Wind s off the polar plateau often blow at storm force. In the interior, however, wind speeds are often moderate. During summer more Solar Radiation reaches the surface at the South Pole than is received at the Equator in an equivalent period. Antarctica is colder than the Arctic for two reasons. First, much of the continent is more than 3 km above sea level, and temperature decreases with elevation. Second, the Arctic Ocean covers the north polar zone. The ocean's relative warmth is transferred through the icepack and prevents temperatures in the Arctic regions from reaching the extremes typical of the land surface of Antarctica. Depending on the latitude, long periods of constant darkness or constant sunlight mean that climates familiar to humans are not generally present on the continent. The Aurora Australis , commonly known as the southern lights, is a glow observed in the night sky near the South Pole. Another unique spectacle is Diamond Dust , a ground-level cloud composed of tiny ice crystals. It generally forms under otherwise clear or nearly clear skies, so people sometimes also refer to it as clear-sky precipitation. A Sundog , a frequent atmospheric Optical Phenomenon , is a bright "spot" beside the true Sun . s in Antarctica]] Population See Also: Demographics of Antarctica Although Antarctica has no permanent residents, a number of governments maintain permanent Research Station s throughout the continent. The population of persons doing and supporting science on the continent and its nearby islands varies from approximately 4000 in summer to 1000 in winter. Many of the stations are staffed around the year. through Microscope s.]] The first settlers of Antarctica (the world region situated south of the Antarctic Convergence ) were English and American sealers who used to spend a year or more on South Georgia , from 1786 onward. During the whaling era, which lasted until 1966, the population of that island varied from over 1000 in the summer (over 2000 in some years) to some 200 in the winter. Most of the whalers were Norwegian, with an increasing proportion of Britons. The settlements included Grytviken , Leith Harbour , King Edward Point , Stromness , Husvik , Prince Olav Harbour , Ocean Harbour and Godthul . Managers and other senior officers of the whaling stations often lived together with their families. Among them was the founder of Grytviken , Captain Carl Anton Larsen , a prominent Norwegian whaler and explorer who adopted British citizenship in 1910. His family included his wife, three daughters and two sons. The first child born in the southern polar region was Norwegian girl Solveig Gunbjörg Jacobsen , born in Grytviken on 8 October 1913 , and her birth registered by the resident British Magistrate of South Georgia . She was a daughter of Fridthjof Jacobsen, the assistant manager of the whaling station, and of Klara Olette Jacobsen. Jacobsen arrived on the island in 1904 to become the manager of Grytviken , serving from 1914 to 1921; two of his children were born on the islandR.K. Headland, The Island of South Georgia, Cambridge University Press, 1984.. 2006 . Flora and fauna See Also: Antarctic ecozone Flora s are known in Antarctica.]] See Also: Antarctic flora The climate of Antarctica does not allow much vegetation to exist. A combination of freezing temperatures, poor Soil quality, lack of moisture and sunlight limit the chances for plants to exist. As a result, plant life is limited to mostly Moss es and Liverwort s. The autotrophic community is made up of mostly Protist s. The Flora of the continent largely consists of Lichen s, Bryophyte s, Algae , and Fungi . Growth generally occurs in the summer, and only for a few weeks at most. There are more than 200 species of lichens and approximately 50 species of bryophytes, such as mosses. Seven hundred species of algae exist, most of which are 2006 . Fauna Land Fauna is completely Invertebrate . Such invertebrate life includes Microscopic Mite s, Lice , Nematode s, and Springtail s. The Midge , just 12 Mm in size, is the largest land animal in Antarctica (other than humans). The Snow Petrel is one of only three birds that breed exclusively in Antarctica and have been seen at the South Pole . s in Ross Sea , Antarctica.]] A variety of marine animals exists, and they rely, directly or indirectly, on the phytoplankton. Antarctic sea life includes 2006 . The passing of the 2006 . Politics As the only uninhabited continent, Antarctica has no government and belongs to no country. Various countries claim areas of it, but most other countries do not recognize those claims. The area between 90°W and 150°W is the only part of Antarctica not claimed by any country. Since 1959 , claims on Antarctica have been suspended and the continent is considered politically neutral. Its status is regulated by the 1959 Antarctic Treaty and other related agreements, collectively called the Antarctic Treaty System . For the purposes of the Treaty System, Antarctica is defined as all land and Ice Shelves south of 60°S. The treaty was signed by 12 countries, including the Soviet Union and the United States . It set aside Antarctica as a scientific preserve, established freedom of scientific investigation, environmental protection, and banned military activity on that continent. This was the first Arms Control agreement established during the Cold War . The Antarctic Treaty prohibits any military activity in Antarctica, such as the establishment of military bases and fortifications, the carrying out of military manoeuvres, or the testing of any type of weapon. Military personnel or equipment are only permitted for scientific research or for any other peaceful purposes.Scientific Committee on Antarctic Research. ''Antarctic Treaty'' Retrieved 2006 . The 2006 . Antarctic territories See Also: Antarctic territorial claims The Argentinean, British and Chilean claims all overlap. Germany also maintained a claim to Antarctica, known as New Swabia , between 1939 and 1945. It was situated from to , overlapping Norway's claim. Economy See Also: Economy of Antarctica has led to several arrests.]] Although coal, hydrocarbons, iron ore, platinum, copper, chromium, nickel, gold and other minerals have been found, they exist in quantities too small to exploit. The 1991 2006 . Small-scale 2006 . Antarctic sight seeing flights (which did not land) operated out of Australia and New Zealand until the fatal crash of Air New Zealand Flight 901 in 1979 on Mount Erebus . Research and 25-second exposure allowed sufficient light into this photo taken at Amundsen-Scott South Pole Station during the long Antarctic night. The new station can be seen at far left, Power Plant in the center and the old mechanic's garage in the lower right.]] See Also: List of research stations in Antarctica Each year, scientists from 27 different nations conduct Experiment s not reproducible in any other place in the world but the Antarctic. In the summer more than 4000 scientists operate Research Station s; this number decreases to nearly 1000 in the winter. The McMurdo Station is capable of housing more than 1000 scientists, visitors, and tourists. Researchers include biologists, geologists, oceanographers, physicists, astronomers, glaciologists, and meteorologists. 2006 . Since the 1970s an important focus of study has been the Ozone Layer in the Atmosphere above Antarctica. In 1985 3 British Scientests working on data they had gathered at Halley Station on the Brunt Ice Shelf discovered the existence of a hole in this layer. In 1998 NASA satellite data showed that the Antarctic Ozone Hole was the largest on record, covering 27 million square kilometers. In 2002 significant areas of ice shelves disintegrated in response to regional warming. , from Mars .]] 2006 . This large collection of meteorites allows a better understanding of the abundance of meteorite types in the solar system and how meteorites relate to asteroids and comets. New types of meteorites and rare meteorites have been found. Among these meteorites are pieces blasted off the moon, and probably Mars, by impacts. These specimens, particularly ALH84001 discovered by ANSMET , are at the center of the controversy about possible evidence of microbial life on Mars. Because meteorites in space absorb and record cosmic radiation, the time elapsed since the meteorite hit the Earth can be determined from laboratory studies. The elapsed time since fall, or terrestrial residence age, of a meteorite represents more information that might be useful in environmental studies of Antarctic ice sheets. See also
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