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Antarctica

Antarctica

:For the Kim Stanley Robinson novel, see Antarctica (novel) Antarctica (from Greek ἀνταρκτικός, "opposite the Arctic") is a continent surrounding the Earth's South Pole. It is the coldest place on Earth and is almost entirely covered by ice; however, it is also the world's largest desert. Although myths and speculation about a Terra Australis ("Southern Land") go back to antiquity, the first commonly accepted sighting of the continent occurred in 1820 and the first verified landing in 1821 by the Russian expedition of Mikhail Lazarev and Fabian Gottlieb von Bellingshausen. (See also History of Antarctica.) With an area of 13,200,000 km², Antarctica is the fifth largest continent, after Asia, Africa, North America, and South America. However, it is by far the smallest in population: indeed, it has no permanent population at all. It is also the continent with the highest average altitude, and the lowest average humidity of any continent on Earth, as well as the lowest average temperature. It has been assigned the Internet ccTLD .aq.

Antarctic climate

.aq Antarctica is the coldest place on earth. Temperatures reach a minimum of between -85 and -90 degrees Celsius in the winter and about 30 degrees higher in the summer months. Weather fronts rarely penetrate far into the continent, leaving the center cold and dry. There is little precipitation over the central portion of the continent, but ice there can last for extended time periods. However, heavy snowfalls are not uncommon on the costal portion of the continent, where snowfalls of up to 48 inches in 48 hours have been recorded. Nearly all of Antarctica is covered by an ice sheet that is, on average, 2.5 kilometers thick. At the edge of the continent, strong katabatic winds off the polar plateau often blow at storm force. In the interior, however, windspeeds are often moderate. Depending on the latitude, long periods of constant darkness, or constant sunlight, mean that climates familiar to humans are not generally available on the continent.

Geography

katabatic wind The continent of Antarctica is located mostly south of the Antarctic Circle, surrounded by the Southern Ocean. Physically Antarctica is divided in two by mountains close to the neck between the Ross Sea and the Weddell Sea. The portion of the continent west of the Weddell Sea and east of the Ross Sea is called Western Antarctica and the remainder Eastern Antarctica, since they correspond roughly to the eastern and western hemispheres relative to the Greenwich meridian. Western Antarctica is covered by the West Antarctic Ice Sheet. See also: Extreme points of Antarctica, Antarctic territories.

Population

It is usually estimated that at a given time there are at least 1,000 people living in Antarctica. This varies considerably with season. Generally, stations use their home country's time zone, but not always; where known, a base's UTC offset is listed. Although Antarctica has no permanent residents, a number of governments maintain permanent research stations throughout the continent. Many of the stations are staffed around the year. These include: staffed
- Akademik Vernadsky Station, Galindez Island, (), ( UKR)
- Amundsen-Scott South Pole Station, South Pole United States Antarctic Program
- Belgrano II, () Laboratory and meteorological station Argentine southernmost base (since 1979).
- Bellingshausen Station, King George Island ()
- Bernardo O'Higgins Station, Antarctic Peninsula, Chilean Army.
- Casey, Vincennes Bay ( Australian Antarctic Division) (UTC+8)
- Comandante Ferraz Station, King George Island ()
- Concordia Research Station, (75° S 123° E),
- Dakshin Gangotri Station, Indian Antarctic Program
- Davis, Princess Elizabeth Land ( Australian Antarctic Division) (UTC+7)
- Dumont d'Urville Station () (UTC+10)
- Eduardo Frei Montalva Station and Villa Las Estrellas, King George Island, Chilean Air Force.
- Esperanza () Laboratory and meteorological station (since 1952). Radio LRA Arcángel, School #38 Julio A. Roca (since 1978), tourist facilities.
- General Artigas Station ()
- Georg von Neumayer Station, () (Atka-Bay) (Alfred Wegener Institute )
- Great Wall Station (), King George Island ()
- Halley Research Station () British Antarctic Survey
- Henryk Arctowski Polish Antarctic Station (), King George Island
- Jubany, (), since 1953 ()
- King Sejong Station (), King George Island, since 1988 ()
- Machu Picchu Research Station, Admiralty Bay, King George Island, summer base established in 1989.
- Macquarie Island ( Australian Antarctic Division)
- Maitri Station, () near Schirmacher Region ( Indian Antarctic Program)
- Marambio Base, () Seymour-Marambio Island. Laboratory, meteorological station, 1.2 km long, 30 m wide landing track (since 1969) () [http://www.marambio.aq website]
- Mawson Station, Mac Robertson Land ( Australian Antarctic Division) (UTC+6)
- McMurdo Station, Ross Island () (UTC+12, follows New Zealand DST)
- Mirny Station () ()
- Mizuho Station () (National Institute of Polar Research )
- Molodezhnaya Station () ()
- Novolazarevskaya Station, Dronning Maud Land () ()
- Orcadas () Orcadas Islands (since 1904)()
- Palmer Station, Anvers Island () (UTC-4, follows Chilean DST)
- Professor Julio Escudero base, King George Island.
- Progress Station () ()
- Rothera Research Station () British Antarctic Survey (UTC-3)
- San Martín Station () (since 1951) Laboratory and Meteorological measurements ()
- SANAE (South African National Antarctic Expeditions), on the Fimbul Coastal Ice Shelf in Queen Maud Land
- Saint Climent Ohridski () (since 1988) Biology Research, Laboratory and Meteorological measurements. First Orthodox Church - St. Ivan Rilski ()
- Scott Base, () Ross Island () (UTC+12, follows New Zealand DST)
- Showa Station () (National Institute of Polar Research ) (GMT+3)
- Troll Station (Norwegian Polar Institute), () Queen Maud Land ()
- Vostok, Antarctica () () (UTC+6)
- Zhongshan (Sun Yet-Sen) Station () () Emilio Marcos Palma was the first person born in Antarctica (Base Esperanza) in 1978, his parents being sent there along with seven other families. Emilio Marcos Palma

Communications

The international dialing code for Antarctica is +672. Antarctica has wireless telephone services. There is a single cell tower using AMPS technology at Argentina's Marambio Base and an Entel Chile GSM tower on King George Island. Communications are otherwise limited to satellite connections. Radio frequencies that can be used are FM2 and shortwave 1.

Military

The Antarctic Treaty prohibits any measures of a military nature in Antarctica, such as the establishment of military bases and fortifications, the carrying out of military maneuvers, or the testing of any type of weapon. It permits the use of military personnel or equipment for scientific research or for any other peaceful purposes. The United States military issues the Antarctica Service Medal to those members of the military or civilians who perform research duty on the Antarctica continent. The medal, including the winter-over bar issued to those who remain on the continent for two complete, six-month seasons, is properly awarded by the United States Congress. The only documented large-scale land military maneuver was "Operación 90," undertaken 10 years before the Antarctic Treaty by the Argentinian military.

External links

- [http://www.70south.com 70South]
- [http://www.ats.org.ar Antarctic Treaty Secretariat]
- [http://www.anetstation.com ANetStation]
- [http://www.add.scar.org The Antarctic Digital Database - a source of digital topographic map data for Antarctica]
- [http://www.ejercito.mil.ar/antartico/historia/antarti_hist.htm Argentine Antarctic history]
- [http://www.aad.gov.au/ Australian Antarctic Division]
- [http://www.antarctica.ac.uk British Antarctic Survey]
- [http://www.comnap.aq/ Council of Managers of National Antarctic Programs (COMNAP)], official homepage.
- [http://www.awi-bremerhaven.de/Polar/index.html German Antarctic Ships and Stations]
- [http://www.loc.gov/rr/international/frd/antarctica/antarctica.html Portals on the World - Antarctica] from the Library of Congress
- [http://www.polarmuseum.sp.ru/Eng/ The Russian State Museum of Arctic and Antarctic]
- [http://www.scar.org The Scientific Committee for Antarctic Research - coordinating body for Antarctic Science]
- [http://members.eunet.at/castaway/stations/aa-bases.html Antarctic Research Stations]
- [http://www.cia.gov/cia/publications/factbook/geos/ay.html The World Factbook – Antarctica] from the U.S. Central Intelligence Agency
- [http://www.70south.com Latest Antarctic news and information by 70South]
- [http://www.planetavivo.org/english/ResearchPrograms/Antarctica/SlideShows/ArdleyIsland/ArdleyIsland1.html Biodiversity at Ardley Island, South Shetland archipelago, Antarctica]
- [http://www.iaato.org International Association of Antarctic Tour Operators (IAATO)] Category:Continents Category:Antarctica Category:Special territories Category:Lists of coordinates ja:南極大陸 ko:남극 ms:Antartika simple:Antarctica th:ทวีปแอนตาร์กติกา zh-min-nan:Lâm-ke̍k-tāi-lio̍k

Kim Stanley Robinson

, August 2005]] Kim Stanley Robinson (born March 23, 1952) is an American science fiction writer, probably best known for his award-winning Mars trilogy. He has been widely acclaimed by readers and critics since the beginning of his career, and is considered by many to be one of the finest living writers of science fiction or of any genre. His work delves into ecological and sociological themes regularly, and many of his novels appear to be the direct result of his own scientific fascinations, such as the 15 years of research and lifelong fascination with Mars which culminated in his most famous work. Robinson's work has been labelled by critics as "literary science fiction"; however he has always rejected such labels — he simply calls it science fiction. Robinson proudly defends the genre for which he is a passionate advocate. Indeed, the quality of his characterization, a common failing in science fiction, has resulted in notice from far broader communities than science fiction generally receives.

Biography

Kim Stanley Robinson was born in Waukegan, Illinois. He studied in California. In 1974 he received a B.A. in literature (University of California, San Diego). At Boston University he gained a M.A. in English in 1975. Robinson received a Ph.D. in English from the University of California, San Diego in 1982. His doctoral thesis The Novels of Philip K. Dick was published in 1984. Robinson is an enthusiastic mountain climber, and this has clearly had a strong influence over several of his works, most notably Antarctica, Mars trilogy, Green Mars (a short story found in The Martians) and Forty Signs of Rain. In 1982 he married Lisa Howland Nowell, an environmental chemist. They have two sons. Robinson has lived in California, Washington, DC, and Switzerland (during the 1980s). He now lives in Davis, California.

Important works

Three Californias trilogy

Davis, California Main article: Three Californias Trilogy This trilogy is also referred to as the Orange County trilogy, and is the first of Robinson's important works. The component books are titled The Wild Shore (1984), The Gold Coast (1988) and Pacific Edge (1990). It is not a trilogy in the traditional sense; rather than telling a single story, the books present three very different yet equally possible future worlds. All three are set in California in the near future. The Wild Shore portrays a California struggling to return to civilisation after having been crippled, along with the rest of America, by a nuclear war. The Gold Coast portrays an overindustralised California increasingly obsessed with and dependent on technology and torn apart by the struggles between arms manufacturers and terrorists, while Pacific Edge presents a California in which ecologically sane, manageable practices have become the norm and the scars of the past are slowly being healed. Though they initially appear unconnected, the three books actually work together to present a unified statement. The first shows humanity crippled by a lack of technology, the second humanity swamped and almost completely dehumanised by too much technology (along with the attendant environmental damage) and the third a workable, livable compromise between the two.

The Mars trilogy

Three Californias Trilogy Main article: Mars trilogy This trilogy is Robinson's most well known work. It is an extended work of hard science fiction dealing with the first settlement of Mars by a group of scientists and engineers. Its three volumes are Red Mars, Green Mars, and Blue Mars, the titles of which mark the changes which the planet undergoes over the course of the story. The tale begins with the first colonists leaving Earth for Mars in 2027, and covers the next 200 years of future history. By the conclusion of the story Mars is heavily populated and terraformed, with a flourishing and complex political and social dimension. There are many threads woven together in the Mars Trilogy. Science, sociology and politics are all covered in great detail, evolving realistically over the course of the narrative. Robinson's fascination with science and technology is clear, though he balances this skillfully with a strong streak of humanity. The characters are rich and engaging, a rare feat in science fiction, hard science fiction especially. Robinson's personal interests, including ecological sustainability, sexual dimorphism and scientific method come through strongly, though never taking on the form of didactic lecturing. His passion for mountain climbing also shows through clearly, though it is worked into the narrative much more elegantly than in some of his later novels.

Antarctica

Main article: Antarctica Antarctica (1997) follows very heavily in the footsteps of the Mars trilogy, and covers much of the same ground despite the differences in setting. It is set on the icy continent of the title, much closer to the present day, but evokes many of the same themes, dealing as it does with scientists in an isolated environment, the effect which this has on their personalities and interactions. It even evokes the same sense of beauty and wonder at a bleak, hostile environment. As with all of Robinson's latter work, ecological sustainability is a major theme in Antarctica. Much of the action is catalysed by the recent expiration of the Antarctic Treaty and the threat of invasion and despoiling of the near-pristine environment by corporate interests.

The Martians

Main article: Mars trilogy The Martians is a collection of short stories set in the same world as the Mars Trilogy. They occur before, during and after the events of the book, some expanding on existing characters and others introducing new ones. It also includes the Constitution of Mars and poetry written 'in character' by a citizen of Mars. It is a useful companion piece to the original trilogy, though some have criticised it as an attempt by Robinson to capitalise or 'cash in' on previous success.

The Years of Rice and Salt

Mars trilogy Main article: The Years of Rice and Salt The Years of Rice and Salt is an epic work of alternate history dealing with a world in which the Black Plague wiped out Europe entirely, leaving the world free for Asian expansion. It covers ten generations of history, focusing on the successive reincarnations of the same few characters as they pass through varying genders, social classes and (in one notable example) species. The Years of Rice and Salt features Muslim, Chinese and Hindu culture and philosophy. Not only because of the long time scale, but because of its realistic-utopian elements, and the frequent reflections about human nature The Years of Rice and Salt resembles the Mars books, brought to Earth. This is a sweeping, epic tale, a bold attempt to contain the entire history of a world into a single volume. At times the reader may find the format frustrating, as they are permitted only a brief glimpse at each stage of the world before the narrative sweeps them on to the next. Nevertheless, the scope alone makes this novel a powerful and important achievement.

Science in the Capital series

Two volumes of a near-future trilogy known as the "Science in the Capital" series have been published to-date: Forty Signs of Rain (2004) and Fifty Degrees Below (2005). This series explores the consequences of global warming, both on a global level, and as it affects the main characters: several employees of the National Science Foundation and those close to them. A recurring theme of Robinson's that returns in this series is that of Buddhist philosophy, this is represented in the series by the agency of ambasadors from Khembalung, a fictional Buddhist state located on an offshore island in the Ganges delta. Their state is threatened by rising sea levels, and the reaction of the Khembalis is compared to that of that of the Washingtonians.

Other novels

- Icehenge (1984) tells the story of the discovery of a monument in the style of Stonehenge found carved from ice on Pluto, and the subsequent investigation into its origin. The setting of this novel bears strong resemblances to that of the Mars trilogy, albeit with darker, more dystopian undertones.
- The Memory of Whiteness (1985) deals with a fantastic, unique musical instrument, and the trials faced by its newest master as he tours the solar system.
- A Short, Sharp Shock (1990) one of Robinson's few fantasy stories, dealing with an amnesiac man travelling through a mysterious land in pursuit of a woman who features in his first memories.

Short stories

His first short stories began appearing in 1976. Most are collected in The Planet on the Table (1986), Remaking History (1991) and Vinland the Dream (2001). Three longer, humorous stories featuring American expatriates in Nepal are collected in Escape from Kathmandu (1989). The Martians (1999) (discussed above) further explores the world of The Mars Trilogy. Complete list:
- "A History of the Twentieth Century, with Illustrations" (in: Vinland the Dream, originally published in Isaac Asimov's Science Fiction Magazine, 1991, revised for Remaking History),
- "A Martian Childhood",
- "A Martian Romance" (in: The Martians),
- "A Sensitive Dependence on Initial Conditions" (in: Vinland the Dream),
- "A Short, Sharp Shock",
- "A Transect",
- "An Argument for the Deployment of All Safe Terraforming Technologies" (in: The Martians),
- "Arthur Sternbach Brings the Curveball to Mars" (in: The Martians),
- "Before I Wake",
- "Big Man in Love" (in: The Martians),
- "Black Air" (in: Vinland the Dream, originally published in The Magazine of Fantasy and Science Fiction, 1983),
- "Coming Back to Dixieland" (in: Vinland the Dream, originally published in Orbit, 18),
- "Coyote Makes Trouble" (in: The Martians),
- "Coyote Remembers" (in: The Martians),
- "Discovering Life" (in: Vinland the Dream and in: The Martians),
- "Down and Out in the Year 2000",
- "Enough is as Good as a Feast" (in: The Martians),
- "Escape from Kathmandu" (in: Escape from Kathmandu),
- "Exploring Fossil Canyon" (in: The Martians),
- "Festival Night",
- "Four Teleological Trails" (in: The Martians),
- "Glacier",
- "Green Mars" (in: The Martians),
- "If Wang Wei Lived on Mars and Other Poems" (in: The Martians),
- "Jackie on Zo" (in: The Martians),
- "Keeping the Flame" (in: The Martians),
- "Maya and Desmond" (in: The Martians),
- "Mercurial" (in: Vinland the Dream, originally published in Universe, 15),
- "Michel in Antarctica" (in: The Martians),
- "Michel in Provence" (in: The Martians),
- "Mother Goddess of the World" (in: Escape from Kathmandu),
- "Muir on Shasta" (in: Vinland the Dream),
- "Odessa" (in: The Martians),
- "On the North Pole of Pluto",
- "Our Town",
- "Purple Mars" (in: The Martians),
- "Remaking History" (in: Remaking History and Vinland the Dream, originally published in Gregory Benford/Martin H. Greenberg What Might Have Been),
- "Ridge Running" (in: Vinland the Dream, originally published in The Magazine of Fantasy and Science Fiction, 1984),
- "Salt and Fresh" (in: The Martians),
- "Saving Noctis Dam" (in: The Martians),
- "Sax Moments" (in: The Martians),
- "Selected Abstracts from The Journal of Aerological Studies" (in: The Martians),
- "Sexual Dimorphism" (in: The Martians),
- "Some Worknotes and Commentary on the Constitution, by Charlotte Dorsa Brevia" (in: The Martians),
- "Stone Eggs" (in: Vinland the Dream, originally published in Universe, 13),
- "The Archaeae Plot" (in: The Martians),
- "The Blind Geometer",
- "The Constitution of Mars" (in: The Martians),
- "The Disguise" (in: Vinland the Dream, originally published in Orbit, 19),
- "The Kingdom Underground" (in: Escape from Kathmandu),
- "The Lucky Strike" (in: Vinland the Dream, originally published in Universe, 14),
- "The Lunatics",
- "The Memorial",
- "The Part of Us That Loves",
- "The Return from Rainbow Bridge",
- "The Translator",
- "The True Nature of Shangri-La" (in: Escape from Kathmandu),
- "The Way the Land Spoke to Us" (in: The Martians),
- "To Leave a Mark",
- "Venice Drowned" (in: Vinland the Dream, originally published in Universe, 11),
- "Vinland the Dream" (in: Vinland the Dream, originally published in Remaking History),
- "What Matters" (in: The Martians),
- "Whose 'Failure of Scholarship'?",
- "Zürich".

Non-fiction

Robinson's doctoral thesis was on the novels of Philip K Dick (1984). A hardcover version was published by UMI Research Press. Robinson edited and wrote the introduction to the anthology Future Primitive: The New Ecotopias (1994).

Major themes

Ecological sustainability

Virtually all of Robinson's novels have an ecological component; it is undoubtedly his primary theme. The Orange County Trilogy is about the way in which the technological intersects with the natural, highlighting the importance of keeping the two in balance. In the Mars Trilogy, one of the principal divisions among the population of Mars is based upon dissenting views on terraforming; whether or not the seemingly barren Martian landscape has the same ecological or spiritual value of a living ecosphere like Earth's is heavily debated. Forty Signs of Rain is entirely ecologically themed, taking as it does global warming for its principal theme.

Economic and social justice

Robinson's work often explores alternatives to modern capitalist society. In the Mars Trilogy, it is argued that capitalism is an outgrowth of feudalism which could be replaced in the future by a more democratic economic system. Worker-ownership and cooperatives figure prominently in Green Mars and Blue Mars as a replacement for traditional corporations. The Orange County Trilogy explores similar arrangements; Pacific Edge includes the idea of attacking the legal framework behind corporate domination to promote social egalitarianism. The environmental and economic/social themes in Robinson's books stand in marked contrast to the Libertarian streak prevalent in much of science fiction (Robert A. Heinlein, Poul Anderson, Larry Niven, and Jerry Pournelle being prominent examples) and his work has been called "the most successful attempt to reach a mass audience with an anti-capitalist utopian vision since Ursula K. Le Guin's 1974 novel, The Dispossessed." [http://www.raintaxi.com/online/2001summer/robinson.shtml] In this sense, Robinson could be said to work within the paradigm of Green politics.

Criticisms

Robinson's writings explore political ideas which contain many elements of socialism and green politics, as well as many alternative lifestyles (including ones where non-monogamous relationships are commonplace). Some reviewers (including, for instance, some readers at Amazon.com) have criticized these aspects of the books by claiming that they represent "Marxist and Green propaganda". However, it can be argued that the Mars trilogy reflects a theme common in most SF: "What if?". It throws many different cultures and beliefs into one harsh space, and watches as they react to their environment, to each other and to the new technologies that infuse their everyday lives. The books suggest that there is not any one theme, one ideology, one belief nor one culture that can shape the colonisation of Mars — instead, it is a new fusion of all of the above which can make a human Mars work.

Prizes

Robinson won Hugos for Green Mars and Blue Mars, Nebulas for Red Mars and "The Blind Geometer" (1986), a World Fantasy Award for "Black Air" (1983), and a John W. Campbell Memorial Award for Pacific Edge. The Memory of Whiteness was awarded the Locus Award.

External links

-
- [http://www.sfsite.com/lists/ksr.htm Short descriptions of K.S. Robinson's novels]
- [http://www.newmars.com/archives/000013.shtml An interview with K.S. Robinson]
- [http://p084.ezboard.com/bthedemimonde The Demimonde: discussion forum]
- [http://www.iblist.com/author508.htm Author's IBList.com Entry]
- [http://books.guardian.co.uk/departments/sciencefiction/story/0,6000,1569830,00.html Guardian interview with K.S. Robinson]
- Robinson, Kim Stanley Robinson, Kim Stanley Robinson, Kim Stanley Robinson, Kim Stanley Robinson, Kim Stanley Robinson, Kim Stanley

Greek language

Greek (Greek Ελληνικά, IPA – "Hellenic") is an Indo-European language with a documented history of 3,500 years. Today, it is spoken by 15 million people in Greece, Cyprus, the former Yugoslavia, particularly The Former Yugoslav Republic of Macedonia, Bulgaria, Albania and Turkey. There are also many Greek emigrant communities around the world, such as those in Melbourne, Australia which is the third-largest Greek-populated city in the world, after Athens and Thessaloniki. Greek has been written in the Greek alphabet, the first true alphabet, since the 9th century B.C. and before that, in Linear B and the Cypriot syllabaries. Greek literature has a long and rich tradition.

History

This article does not cover the reconstructed history of Greek prior to the use of writing. For more information, see main article on Proto-Greek language. Greek has been spoken in the Balkan Peninsula since the 2nd millennium BC. The earliest evidence of this is found in the Linear B tablets dating from 1500 BC. The later Greek alphabet (q.v.) is unrelated to Linear B, and was derived from the Phoenician alphabet (abjad); with minor modifications, it is still used today. Greek is conventionally divided into the following periods:
- Mycenean Greek: the language of the Mycenean civilisation. It is recorded in the Linear B script on tablets dating from the 16th century BC onwards.
- Classical Greek (also known as Ancient Greek): In its various dialects was the language of the Archaic and Classical periods of Greek civilisation. It was widely known throughout the Roman empire. Classical Greek fell into disuse in western Europe in the Middle Ages, but remained known in the Byzantine world, and was reintroduced to the rest of Europe with the Fall of Constantinople and Greek migration to Italy.
- Hellenistic Greek (also known as Koine Greek): The fusion of various ancient Greek dialects with Attic (the dialect of Athens) resulted in the creation of the first common Greek dialect, which gradually turned into one of the world's first international languages. Koine Greek can be initially traced within the armies and conquered territories of Alexander the Great, but after the Hellenistic colonisation of the known world, it was spoken from Egypt to the fringes of India. After the Roman conquest of Greece, an unofficial diglossy of Greek and Latin was established in the city of Rome and Koine Greek became a first or second language in the Roman Empire. Through Koine Greek it is also traced the origin of Christianity, as the Apostles used it to preach in Greece and the Greek-speaking world. It is also known as the Alexandrian dialect, Post-Classical Greek or even New Testament Greek (after its most famous work of literature).
- Medieval Greek: The continuation of Hellenistic Greek during medieval Greek history as the official and vernacular (if not the literary nor the ecclesiastic) language of the Byzantine Empire, and continued to be used until, and after the fall of that Empire in the 15th century. Also known as Byzantine Greek.
- Modern Greek: Stemming independently from Koine Greek, Modern Greek usages can be traced in the late Byzantine period (as early as 11th century). Two main forms of the language have been in use since the end of the medieval Greek period: Dhimotikí (Δημοτική), the Demotic (vernacular) language, and Katharévousa (Καθαρεύουσα), an imitation of classical Greek, which was used for literary, juridic, and scientific purposes during the 19th and early 20th centuries. Demotic Greek is now the official language of the modern Greek state, and the most widely spoken by Greeks today. It has been claimed that an "educated" speaker of the modern language can understand an ancient text, but this is surely as much a function of education as of the similarity of the languages. Still, Koinē , the version of Greek used to write the New Testament and the Septuagint, is relatively easy to understand for modern speakers. Greek words have been widely borrowed into the European languages: astronomy, democracy, philosophy, thespian, etc. Moreover, Greek words and word elements continue to be productive as a basis for coinages: anthropology, photography, isomer, biomechanics etc. and form, with Latin words, the foundation of international scientific and technical vocabulary. See English words of Greek origin, and List of Greek words with English derivatives.

Classification

Greek is an independent branch of the Indo-European language family. The ancient languages which were probably most closely related to it, Ancient Macedonian language (which may be regarded as a dialect of Greek) and Phrygian, are not well enough documented to permit detailed comparison. Among living languages, Armenian seems to be the most closely related to it.

Geographic distribution

Modern Greek is spoken by about 15 million people mainly in Greece and Cyprus. There are also Greek-speaking populations in Georgia, Ukraine, Egypt, Turkey, Albania, Former Yugoslav Republic of Macedonia and Southern Italy. The language is spoken also in many other countries where Greeks have settled, including Armenia, Australia, Austria, Belgium, Bulgaria, Canada, Denmark, France, Germany, Netherlands, Sweden, United Kingdom, and the United States.

Official status

Greek is the official language of Greece where it is spoken by about 99.5% of the population. It is also, alongside Turkish, the official language of Cyprus. Due to the membership of Greece and Cyprus, Greek is one of the 20 official languages of the European Union.

Phonology

This section generally describes the post-Classic phonology of the Greek language. :All phonetic transcriptions in this section use the International Phonetic Alphabet

Vowel sounds

Greek has 5 vowel sounds, all phonemic:

Arctic

The Arctic is the area around the Earth's North Pole. The Arctic includes parts of Russia, Alaska (United States), Canada, Greenland (a territory of Denmark), Iceland, and Scandinavia (Norway, Sweden, and Finland), as well as the Arctic Ocean. There are numerous definitions for the Arctic region. The boundary is generally considered to be north of the Arctic Circle (66° 33’N), which is the limit of the midnight sun and the polar night. Other definitions are based on climate and ecology, such as the 10°C (50°F) July isotherm, which also roughly corresponds to the tree line in most of the Arctic. Socially and politically, the Arctic region includes the northern territories of the eight Arctic states, including Lapland, although by natural science definitions much of this territory is considered subarctic. The Arctic is mostly a vast, ice-covered ocean, surrounded by tree-less, frozen ground, that teems with life, including organisms living in the ice, fish and marine mammals, birds, land animals and human societies. The Arctic region is by its nature a unique area. The cultures in the region and the Arctic indigenous peoples have adapted to its cold and extreme conditions. From the perspective of the physical, chemical and biological balance in the world, the Arctic region is in a key position. It reacts sensitively particularly to changes in the climate, which reflect extensively back on the global state of the environment. From the perspective of research into climatic change, the Arctic region is considered a so-called-early warning system. The Arctic is also known as the Land of the Midnight Sun as it is within the Arctic Circle. The name Arctic comes from the ancient Greek αρκτος, meaning 'bear', and is a reference to the constellations of the Great Bear and Little Bear, which are located near the North Star (which is actually part of the Little Bear).

Nature and natural resources

Nature in the Arctic is comparatively clean although there are certain ecologically difficult localized pollution problems that present a serious threat to people’s health living around these pollution sources. Due to the prevailing worldwide sea and air currents, the Arctic area is the fall out region for long-range transport pollutants and in some places the concentrations exceed the levels of densely populated urban areas. The Arctic region includes sizeable potential natural resources (oil, gas, minerals, forest and fish) to which modern technology and the opening up of Russia have given significant new opportunities. The interest of the tourism industry in the cold and exotic Arctic is also on the increase. This is for example, seen in the rise in international tourism as a significant opportunity but also as a threat. The Arctic region is one of the last and most extensive continuous wilderness areas in the world and its significance in preserving biodiversity and genotypes is considerable. The increasing presence of people fragments vital habitats. The Arctic is particularly susceptible to the abrasion of groundcover and to the disturbance of the rare reproduction places of the animals that are characteristic to the region. External link: [http://amap.no/ AMAP - the Arctic Monitoring and Assessment Programme]

Arctic cultures

Also noteworthy is the fact that a significant proportion of the population in the region are indigenous peoples (e.g. the Nenets, Koms, Khants and Sami) who practice subsistence livelihoods such as reindeer husbandry and fishing and whose rights are many times in jeopardy due to "development".
- Aleut
- Athabaskan
- Chukchi
- Inuit
- Inupiaq
- Nenets
- Pomor
- Saami
- Yup'ik External link: [http://www.allthingsarctic.com/people/index.aspx Native peoples]

The changing Arctic

Along with increasing utilization, it is likely that in the coming decades, new investments, industry and building an infrastructure as well as the increasing mobility of goods, services, people and capital are to be expected. These will all have an effect on the environment of the region and on the local conditions of the population and indigenous peoples. The above-described global change is expected to have the overwhelmingly large impact in the near future on the diversity of nature and cultures in the arctic and northern regions and on the recreational value of the Arctic and its natural resources. The impacts from the changes will reflect in many ways on the ecosystems of the region, its biodiversity, livelihoods, social and legal structures and indirectly on almost all life in the region. The Arctic Climate Impact Assessment (ACIA), released in November 2004, details some of the future scenarios for long-term climate change that are already beginning to be seen in the Arctic region today. NOAA tracks the [http://www.arctic.noaa.gov/detect/overview.shtml current state of the Arctic ecosystems and climate] on the near-realtime [http://www.arctic.noaa.gov/detect/ Arctic Change website]. A narrative style is used to highlight land and marine ecosystems, the cryosphere, Arctic and sub-Arctic human impacts, and an overall [http://www.arctic.noaa.gov/detect/indicators.shtml summary] evaluates recent reports against historical information. External links:
- [http://www.acia.uaf.edu/ ACIA Report]
- [http://www.arctic.noaa.gov/detect/ Arctic Change website] - NOAA website provides up-to-date information on the current state of Arctic ecosystems and climate in historical context.

Environmental impact assessment

From the perspective of positive development in the Arctic region, an environmental impact assessment (EIA) is in a key position. In the Arctic region, it is important that in a process, special attention is given to assessing social impacts. It is generally known that scientific information focused on the Arctic region is insufficient, so the actors conducting an EIA do not get sufficient material in order to compile a precise assessment. Developing a dialogue between new actors in the region, business life and the local population is important so that mutual understanding and often conflicting needs for development can be improved. Improving access to information by local inhabitants, well functioning participatory planning and ensuring the optimum use of its results are part of this activity. The horizontal processing of administration by different sectors in society that is required for an EIA necessitates for its support the production of strong multidisciplinary information. Managing and analyzing the above-mentioned multidimensional and demanding process requires combining many scientific fields and methods and further scientific analysis and development of functional models.

International cooperation and politics

The Arctic region is one of the important focuses of international political interest. International Arctic cooperation got underway on a broad scale well over ten years ago. The International Arctic Science Committee (IASC), hundreds of scientists and specialists of the Arctic Council, the Barents Council and its regional cooperation have compiled high quality information

A strategic military region

The Arctic has never been under the political control of any nation although some nations' militaries have attached a strategic importance to the region. In the 1950s and 1960s, the arctic was often used by submarines to test new weapons, sonar equipment, and depth testing. During the Cold War, the Arctic region was extensively monitored by the United States military, since it was the opinion of the said military that the first warnings of a Soviet Union nuclear strike would have been indicated by ICBMs launched over the North Pole towards the United States. The United States placed such importance on the region that two military decorations, the Arctic Service Ribbon and Coast Guard Arctic Service Medal, were established for military duty performed within the arctic circle.

References

- [http://www.arcticcentre.org Arctic Centre, Rovaniemi] Arctic research
- [http://www.wordreference.com/english/definition.asp?en=arctic WordReference.com Dictionary] Etymology
- [http://www.cia.gov/cia/publications/factbook/reference_maps/pdf/arctic.pdf CIA World Factbook 2002 - Arctic Region] Large version of the arctic region map
- [http://www.arctic.noaa.gov Arctic Theme Page] Comprehensive Arctic Resource from NOAA.
- [http://www.beringclimate.noaa.gov Bering Sea Climate and Ecosystem] Current state of the Bering Sea Climate and Ecosystem. Comprehensive resource on the Bering Sea with viewable oceanographic, atmospheric, climatic, biological and fisheries data with ecosystem relevance, recent trends, essays on key Bering Sea issues, maps, photos, animals and more. From NOAA.
- [http://www.unaami.noaa.gov Arctic time series: The Unaami Data collection] Viewable interdisciplinary, diverse collection of Arctic variables from different geographic regions and data types.
- [http://www.allthingsarctic.com/exploration/index.aspx Arctic exploration and history]
- [http://www.allthingsarctic.com/science/index.aspx Arctic research]

External links

- [http://www.arctic-council.org Arctic Council]
- [http://www.arctic.noaa.gov Arctic]
- [http://www.arctic.noaa.gov/detect/ Near-Realtime Arctic Change Indictors]
- [http://maps.grida.no/arctic Arctic Environmental Atlas] Circum-Arctic interactive map, with multiple layers of information
- [http://www.globio.info/region/polar/#arctic GLOBIO Human Impact maps] How does humans influence one of the last remaining wild places on the globe
- [http://www.vitalgraphics.net/arctic.cfm Vital Arctic Graphics] Overview and case studies of the Arctic environment and the Arctic Indigenous Peoples.
- [http://www.canadiangeographic.ca/atlas/themes.aspx?id=artic&lang=En Arctic and Taiga Canadian Atlas]

Continent

shows land mass with minimal distortion as only one continuous continent]] A continent (Latin continere, "to hold together") is a large continuous land mass. There are several conceptions of what a continent is, geographic, geologic, and tectonic.

Geographic continents

Because geography is defined by local convention, there are several conceptions as to which landmasses qualify as continents. There are names for six, but America is often divided, and Europe is often united with Asia. Ignoring cases where Antarctica is omitted, there are half a dozen lists. tectonic The 7-continent model is usually taught in Western Europe, the United States, Australia, and much of Asia. In Canada, the government-approved [http://atlas.gc.ca/site/english/maps/reference/international/world/referencemap_image_view Atlas of Canada] names 7 continents and teaches Oceania instead of Australia. The 6-continent combined-America model is taught in Iran, and Latin America. The 6-continent Eurasia model is preferred by the scientific community, and as such is commonly found in all parts of the world, but is especially used in Russia and other countries of Eastern Europe, and in Japan. Historians may use the 5-continent model in which North Africa is separated from Sub-Saharan Africa and attached to Eurasia (Jared Diamond) or the 4-continent Afro-Eurasian model (Andre Gunder Frank). In its original sense, "continent" meant (and still means) mainland. In the Greco-Roman world, there was but one known, the Continent, which we today call the Old World. In the mid 1600s Peter Heylin wrote in his Cosmographie that "A Continent is a great quantity of Land, not separated by any Sea from the rest of the World, as the whole Continent of Europe, Asia, Africa." As late as 1727 Ephraim Chambers wrote in his Cyclopædia, "The world is ordinarily divided into two grand continents: the old and the new." However, since Classical times this Continent was divided into "peninsulas" which also came to be called continents, since they were great land masses themselves. Through the Middle Ages, there were three such continents in the Western conception: Europe, Africa, and Asia. The European discovery of America in 1492 made four; and Australia in 1606 would make five, though not right away: as late as 1813 geographers wrote of Australia as "New Holland, an immense Island, which some geographers dignify with the appellation of another continent". However, dividing America in two was commonplace by this time, and would also produce a fifth continent. The idea of the Five Continents is still strong in Europe and Asia, and is represented by the five rings on the Olympic flag. Antarctica was sighted in 1820, for the sixth and last continent to be given a separate name, though a great "antarctic" (antipodean) landmass had been anticipated for millennia. Dividing the Americas now made seven continents, nicely symmetrical with the magical number of the Seven Seas, Seven Heavens, and the seven heavenly bodies that gave their names to the seven days of the week. However, this division never appealed to Latin America, which saw itself spanning America as a single landmass, and there the conception of six continents remains, as it does in scattered other countries such as Japan. From a modern perspective, the continent with the least reason for separate recognition is Europe, and in scientific circles people generally prefer to subsume Europe and Asia into Eurasia. This appealed to Russia, which spans Eurasia, and in Russia and (at least formerly) in Eastern Europe, Eurasia is or was taught as being one of six continents. Geographers and historians often find it useful to define larger land masses connected by land bridges: # Africa-Eurasia (also called Eurafrasia): the combined land mass of Africa and Eurasia; # America (or the Americas): the combined land mass of North America and South America; # Laurasia: the combined land mass of Eurasia and North America, which were connected by Beringia during the Ice Age; # Sahul: the combined land mass of Australia, New Guinea, and Tasmania during the Ice Age. That is, during the last Ice Age, there were three large landmasses: Africa-Eurasia + America (which has no name), Sahul, and Antarctica. These larger land masses are usually considered supercontinents rather than continents, however. In the last century it has also become conventional to subdivide Eurasia into the regions of Europe, Asia, and the Middle East. America is often divided into the regions of North America, Central America, and South America. Continents are also sometimes subdivided into subcontinents that are isolated by geological features. The prototype of this is the Indian subcontinent. Islands are usually considered to belong geographically to the continent they are closest to. The Coral Sea and South Pacific islands may be associated with Australia/Australasia to form the "continent" of Oceania (though the Pacific islands without Australia are also called Oceania). The British Isles have always been considered part of Europe, and Greenland is considered part of North America. When the Continent is referred to without clarification by a speaker of British English, it is usually presumed to mean Continental Europe, that is Europe, explicitly excluding Great Britain and Ireland. The Continental United States excludes Hawaii. Contiguous or Co(n)terminous United States means the United States without Alaska or Hawaii (the "Lower 48"), but it is very common for people to say continental for contiguous. See also List of countries by continent, Satellite Images of Continents.

Geologic continents

Geologically, the surface of Earth consists of many tectonic plates, consisting of rigid lithospheric mantle and crust moving together over the much less viscous asthenosphere. Continental crust is primarily granitic in composition, overlain by sedimentary and metamorphic rocks. Much of the continental crust extends above sea level as dry land. Oceanic crust is basaltic in composition, and much thinner than continental crust, thus generally lying below sea level. Although from a human perspective shallow inland seas such as the Bering Sea appear to divide up land masses into continents, such ephemeral features do not define continents geologically. For instance, many times over the past few million years, the continents of Eurasia and America were connected by dry land. A geologic continent, therefore, is a continuous piece of continental crust, whether wet or dry at a particular time. As such, Laurasia and Africa-Arabia are one continent, which for the past three million years has also been linked to South America. This world-spanning land mass has no name except for the Classical meaning of "The Continent". The other large geologic continents are Sahul and Antarctica, but there are many so-called microcontinents as well: Madagascar, the Seychelles (the northern Mascarene Plateau), New Zealand, New Caledonia, etc., which are splinters of the ancient supercontinent of Gondwana. Note that volcanic Iceland is an exposed bit of oceanic crust at the mid-ocean ridge, and therefore not a microcontinent. Likewise, the British Isles, Sri Lanka, Borneo, and Newfoundland are integral parts of the Laurasian continent which happen to be separated by shallow (and temporary) inland seas flooding its margins.

Tectonic plates

During the 20th century, it became accepted by geologists that continents move location on the face of the planet over the geologic timescale, a process known as continental drift, explained by the theory of plate tectonics. It is the tectonic plates that have drifted, broken apart and joined together over time to give rise to the continents we now recognize. Consequently, in the geological past and prior to the present continents, other continents existed - see :Category:Historical continents. Occasionally there are calls for the continents to be defined by the tectonic plates that carry them. However, not only would this make Arabia on the Arabian plate and India on the Indian plate continents, but also Central America on the Caribbean plate and California on the Pacific plate, and this definition has never been widely accepted.

South Pole

The South Pole is the southernmost point on the Earth, as defined in any of several ways.

Geographic South Pole

The Geographic South Pole is the one of two points where the earth's axis of rotation intersects the surface (the other being the Geographic North Pole). This is the point usually meant when an unspecified "south pole" is mentioned. The first humans to reach the Geographic South Pole were Norwegian Roald Amundsen and his party on December 14, 1911. Amundsen named his camp Polheim. Amundsen's main competitor Robert Falcon Scott reached the Pole a month later. On the return trip Scott and his party of four all died of hunger and extreme cold. There have been many expeditions to arrive at the South Pole by surface transportation. The leaders of some of the first of these are, in order: Amundsen, Scott, Hillary, Fuchs, Havola, Crary, Fiennes. US Admiral Richard Byrd on November 29, 1929 became by the assistance of his first pilot Bernt Balchen the first person to fly over the South Pole. The fastest unsupported walking journey to the Geographic South Pole from the ocean is 47 days and was set in 1999 by explorers Tim Jarvis and Peter Treseder, who manhauled 200 kg sleds containing food and cooking fuel. At present, Antarctica is located over the South Pole, although this has not been the case for all of Earth's history because of continental drift. The Amundsen-Scott South Pole Station was established during the International Geophysical Year in 1958 and is permanently staffed by research and support personnel. The projection of the south geographic pole onto the celestial sphere gives the south celestial pole. The land at the South Pole is located near sea level. However, the ice cap is 3000 metres thick and consequently the Amundsen-Scott Base is a high altitude location.

Ceremonial South Pole

celestial pole celestial pole The Ceremonial South Pole is an area set aside for photo opportunities at Amundsen-Scott South Pole Station. It consists of a metallic sphere on a plinth, surrounded by the flags of the Antarctic Treaty signatories. It is located a few hundred metres from the Geographic South Pole (see above), which is marked only by a small sign and a stake. The dome seen in the pictures is partially buried due to snow storms. The entrance to the dome has to be regularly bulldozed to uncover it. More recent buildings are now built on stilts so that the snow does not build up against the side of them.

Geomagnetic South Pole

The South Magnetic Pole is one of the two magnetic poles of the Earth's magnetic field. It lies near the Geographic South Pole, but its exact location is gradually shifting. The South Magnetic Pole is named after its proximity to the Geographic South Pole; in a strict magnetic sense, it is a north pole. The south pole of a magnet is attracted to the north poles of other magnets, hence the south pole of a freely suspended magnet (as in a compass) will point towards the Geomagnetic South Pole.

Magnetic South Pole

The Magnetic South Pole is the point nearest the Geographic South Pole where the field lines of Earth's magnetic field point directly into the ground. It does not coincide with the Geomagnetic South Pole. On 16 January, 1909 three men (Douglas Mawson, Edgeworth David, and Alistair Mackay) from an expedition led by Sir Ernest Shackleton, found the Magnetic South Pole [http://www.antarctica.ac.uk/About_Antarctica/FAQs/faq_05.html].

The Pole of Relative Inaccessibility

It is located at on the surface of the Antarctic continent and is the most distant point from the Southern Ocean. It was reached on December 14 1958 by the 3rd Soviet Antarctic Expedition, lead by Yevgeny Tolstikov. At that point they established a temporary station Polyus Nedostupnosti. On the road to the Pole, at another station, Sovetskaya, was established by the expedition, which existed between February 16 1958 and January 3 1959.

External links

- [http://www.70south.com/resources/bases/amundsen South Pole Station info on 70South]
- [http://www.phys.unsw.edu.au/southpolediaries/webcam.html South Pole Webcam]
- [http://astro.uchicago.edu/cara/vtour/pole/ Virtual tour of the South Pole]
-
- [http://www.cmdl.noaa.gov/gallery/SPO South Pole Photo Gallery]
- [http://www.wunderground.com/global/stations/89009.html Current weather conditions at the South Pole (Amundsen-Scott Station)]
- [http://spadventure.blogspot.com/ "A south pole adventure"] - blog of a scientist at the station Category:Geography of Antarctica Category:Antarctica Category:Poles ko:남극점 ja:南極点 simple:South Pole

Ice

] Ice is the solid form of water. The phase transition occurs when liquid water is cooled below 0 °C (273.15 K, 32 °F) at standard atmospheric pressure. An unusual feature of ice frozen at a pressure of one atmosphere is that the solid is some 8% less dense than liquid water. Ice has a density of 0.917 g/cm³ at 0 °C, whereas water has a density of 0.9998 g/cm³ at the same temperature. Liquid water is most dense, essentially 1.00 g/cm³, at 4 °C and becomes less dense as the water molecules begin to form the hexagonal crystals of ice as the temperature drops to 0 °C. (In fact, the word "crystal" derives from the Greek word for frost.) This is due to hydrogen bonds forming between the water molecules, which line up molecules less efficiently (in terms of volume) when water is frozen. The result of this is that ice floats on liquid water, an important factor in Earth's climate. When ice melts, it absorbs as much heat energy (the heat of fusion) as it would take to heat an equivalent mass of water by 80 °C, while its temperature remains a constant 0 °C. As a crystalline solid, ice is considered a mineral.

Types of ice

mineral Everyday ice and snow is hexagonal ice (ice I_h). Subjected to higher pressures and varying temperatures, ice can form in roughly a dozen different phases. Only a little less stable (metastable) than I_h is cubic structure ice (I_c). But cooling I_h causes a different arrangement to form in which the protons move, XI. With both cooling and pressure more types exist, each being created depending on the phase diagram of ice. These are II, III, V, VI, VII, VIII, IX, and X. With care all these types can be recovered at ambient pressure. The types are differentiated by their crystalline structure, ordering and density. There are also two metastable phases of ice under pressure, both fully hydrogen disordered, these are IV and XII. Ice XII was discovered in 1996. As well as crystalline forms solid water can exist in amorphous states as amorphous solid water (ASW), low density amorphous ice (LDA), high density amorphous ice (HDA), very high density amorphous ice (VHDA) and hyperquenched glassy water (HGW). Kurt Vonnegut's novel Cat's Cradle features Ice IX as a central element of the plot, although real Ice IX does not have the properties of Vonnegut's fictional ice-nine (i.e. the ability to freeze all water on Earth with the introduction of one granule). Rime is a type of ice formed by fog freezing on cold objects. It contains a high proportion of trapped air, making it appear white rather than transparent, and giving it a density about one quarter of that of pure ice. Ice can also form icicles, similar to stalactites in appearance, as water drips and re-freezes. Clathrate hydrates are forms of ice that contain gas molecules trapped within its crystal lattice. Pancake ice is a formation of ice generally created in areas with less calm conditions. Some other substances (particularly solid forms of those usually found as fluids) are also called "ice": dry ice, for instance, is a popular term for solid carbon dioxide. carbon dioxide, circa 1905.]]

Human relationship with ice

carbon dioxide, Iran, built during the Middle Ages for storing harvested ice.]] Ice has long been valued as a means of cooling. Until recently, the Hungarian Parliament building used ice harvested in the winter from Lake Balaton as its primary source of energy for air conditioning. Icehouses were used to store ice during the winter so as to preserve perishables during the summer, and early refrigerators were known as iceboxes because they had a block of ice in them. In many cities it was not unusual to have a regular ice delivery service during the summer. The advent of artificial refrigeration technology has since made delivery of ice obsolete. In 400 BC Iran, Persian engineers had already mastered the technique of storing ice in the middle of summer in the desert. The ice was brought in during the winters from nearby mountains in bulk amounts, and stored in specially designed, naturally cooled refrigerators, called yakhchal (meaning ice storage). This was a large underground space (up to 5000 m³) that had thick walls (at least two meters at the base) made out of a special mortar called sārooj, composed of sand, clay, egg whites, lime, goat hair, and ash in specific proportions, and which was resistant to heat transfer. This mixture was thought to be completely water impenetrable. The space often had access to a Qanat, and often contained a system of windcatchers that could easily bring temperatures inside the space down to frigid levels in summer days. The ice was then used to chill treats for royalty during hot summer days.

Sports on ice

Ice also plays a role in winter recreation, in sports such as ice skating, ice hockey, ice fishing, ice climbing and sled racing on bobsled and luge. The human quest for excitement has even led to ice racing, where drivers must go fast on lake ice while also controlling the skid of their vehicle (this is similar in some ways to dirt track racing). The sport has even been modified to work on ice rinks.

Ice travel

ice rink, February 2002.]] Ice can also be an obstacle; for harbors near the poles, being ice-free is an important advantage, ideally all-year round. Examples are Murmansk (Russia), Petsamo (Russia, formerly Finland) and Vardø. Harbors that are not ice-free are opened up using icebreakers. Ice forming on roads is a dangerous winter hazard. Black ice is very difficult to see because it lacks the expected glossy surface. Whenever there is freezing rain or snow that occurs at a temperature near the melting point, it is common for ice to build up on the windows of vehicles. Driving safely requires the removal of the ice build-up. Ice scrapers are tools designed to break the ice free and clear the windows, though removing the ice can be a long, labor-intensive, and stressful process—especially when a driver ends up running late for work as a result. Far enough below the freezing point, a thin layer of ice crystals can form on the inside surface of windows. This usually happens when a vehicle has been left alone after being driven for a while, but can happen while driving if the outside temperature is low enough. Moisture from the driver's breath is the source of water for the crystals. It is troublesome to remove this form of ice, so people often open their windows slightly when the vehicle is parked in order to let the moisture dissipate, and it is now common for cars to have rear-window defrosters to combat the problem. A similar problem can happen in homes, which is why many colder regions require double-pane windows for insulation. When the outdoor temperature stays below freezing for extended periods, very thick layers of ice can form on lakes and other bodies of water (although places with flowing water require much colder temperatures). The ice can become thick enough to drive onto with automobiles and trucks. Doing this safely requires a thickness of at least 30 centimeters (one foot).

Other uses of ice

- The manufacture and use of ice cubes or crushed ice is common for drinks.
- Pagophagia, a type of pica eating disorder, is the compulsive consumption of ice.
- Structures are built out of large chunks of ice. They are mostly ornamental (as in the case with ice castles) and not practical for long-term habitation. Ice hotels exist on a seasonal basis in a few cold areas. Igloos are another example of a temporary structure.

Ice at different pressures

Ice can be formed at higher temperatures in pressurized environments, and water will remain a liquid or gas until -30 °C at lower pressures. Ice formed at high pressure has a different crystal structure and density than ordinary ice. Ice, water, and water vapor can coexist at the triple point, which is 273.16 K at a pressure of 611.73 Pa.

Related terms

- A rusticle is a rust formation similar to an icicle.
- Isaz is the Proto-Germanic rune for "ice".

External links

- [http://www.its.caltech.edu/~atomic/snowcrystals/ice/ice.htm The phase diagram of water, including the ice variants]
- [http://www.webmineral.com/data/Ice.shtml Webmineral listing for Ice]
- [http://www.mindat.org/min-2001.html MinDat.org listing and location data for Ice]
- [http://www-2.cs.cmu.edu/~dst/ATG/ice.html The physics of ice]
- [http://www.martin.chaplin.btinternet.co.uk/phase.html The phase diagrams of water with some high pressure diagrams]
- [http://www.livescience.com/forcesofnature/050630_melting_discovery.html A recent discovery about how ice melts] Category:Forms of water Category:Water ice Category:Glaciology Category:Minerals als:Eis ja:氷 simple:Ice

Desert

In geography, a desert is a landscape form or region that receives little precipitation - less than 250 mm per year. Deserts have a reputation for supporting very little life. Compared to wetter regions this may be true, although upon closer examination, deserts often harbor a wealth of life that usually remains hidden (especially during the daylight) to preserve moisture. Approximately one-third of Earth's land surface is desert. (See a map of the world's non-polar deserts, http://pubs.usgs.gov/gip/deserts/what/world.html.) Desert landscapes have certain common features. Desert soil is often composed mostly of rocky surfaces called regs. Sand dunes called ergs and stony or hamada surfaces compose the minority of desert surfaces. Exposures of rocky terrain are typical, and reflect minimal soil development and sparseness of vegetation. Bottom lands may be salt-covered flats. Eolian (wind-driven) processes are major factors in shaping desert landscapes. Deserts sometimes contain valuable mineral deposits that were formed in the arid environment or that were exposed by erosion. Because deserts are dry, they are ideal places for human artifacts and fossils to be preserved. In the Köppen climate classification system, they are classed as (BW).

Types of desert

Most classifications rely on some combination of the number of days of rainfall, the total amount of annual rainfall, temperature, humidity, or other factors. In 1953, Peveril Meigs divided desert regions on Earth into three categories according to the amount of precipitation they received. In this now widely accepted system, extremely arid lands have at least 12 consecutive months without rainfall, arid lands have less than 250 millimeters of annual rainfall, and semiarid lands have a mean annual precipitation of between 250 and 500 millimeters. Arid and extremely arid land are deserts, and semiarid grasslands generally are referred to as steppes. However, lack of rainfall alone can't provide an accurate description of what a desert is. For example, Phoenix, Arizona receives less than 250 millimeters, (10 inches), of precipitation per year, and is immediately recognized as being located in a desert. The North Slope of Alaska's Brooks Range also receives less than 250 millimeters of precipitation per year, but is not generally recognized as a desert region. The difference lies in something termed "potential evapotranspiration." The water budget of an area can be calculated using the formula P-PE+/-S, whereby P is precipitation, PE is potential evapotranspiration rates and S is amount of surface storage of water. Evapotranspiration is the combination of water loss through atmospheric evaporation, coupled with the evaporative loss of water through the life processes of plants. Potential evapotranspiration, then, is the amount of water that could evaporate in any given region. Tucson, Arizona receives about 300 millimeters, (12 inches), of rain per year, however about 2500 millimeters, (100 inches), of water could evaporate over the course of a year. In other words, about 8 times more water could evaporate from the region than actually falls. Rates of evapotranspiration in other regions such as Alaska are much lower, so while these regions receive minimal precipitation, they should be designated as specifically different from the simple definition of a desert: a place where evaporation exceeds precipitation. That said, there are different forms of deserts. Cold deserts can be covered in snow; such locations don't receive much precipitation, and what does fall remains frozen as snow pack; these are more commonly referred to as tundra if a short season of above-freezing temperatures is experienced, or as an ice cap if the temperature remains below freezing year-round, rendering the land almost completely lifeless. Most non-polar deserts are hot because they have little water. Water tends to have a cooling, or at least a moderating, effect in environments where it is plentiful. In some parts of the world deserts are created by a rain shadow effect in which air masses lose much of their moisture as they move over a mountain range; other areas are arid by virtue of being very far from the nearest available sources of moisture (this is true in some middle-latitude landmass interior locations, particularly in Asia). Deserts are also classified by their geographical location and dominant weather pattern as trade wind, midlatitude, rain shadow, coastal, monsoon, or polar deserts. Former desert areas presently in nonarid environments are paleodeserts, and extraterrestrial deserts exist on other planets.

Montane deserts

Montane deserts are arid places with a very high altitude; the most prominent example is found north of the Himalaya, in parts of the Kunlun Mountains and the Tibetan Plateau. Many locations within this category have elevations exceeding 3,000 meters (9,843 feet) and the thermal regime can be hemiboreal. These places owe their profound aridity (the average annual precipitation is often less than 40mm) to being very far from the nearest available sources of moisture.

Desert features

hemiboreal] Sand covers only about 20 percent of Earth's deserts. Most of the sand is in sand sheets and sand seas—vast regions of undulating dunes resembling ocean waves "frozen" in an instant of time. In general, there are 6 forms of deserts: i.Mountain and basin deserts, ii. Hamada deserts, which comprise of a plateaux landforms, iii. Regs which consist of rock pavements, iv. Ergs which are formed by sand seas, v. Intermontane Basins, and vi. Badlands which are located at the margins of arid lands comprising of clay-rich soil. Nearly 100 percent of desert surfaces are plains where eolian deflation—removal of fine-grained material by the wind—has exposed loose gravels consisting predominantly of pebbles but with occasional cobbles. The remaining surfaces of arid lands are composed of exposed bedrock outcrops, desert soils, and fluvial deposits including alluvial fans, playas, desert lakes, and oases/oasis. Bedrock outcrops commonly occur as small mountains surrounded by extensive erosional plains. There are several different types of dunes. Barchan dunes are produced by strong winds blowing across a level surface and are crescent shaped. Longitudinal or seif dunes are dunes that are parallel to a strong wind that blows in one general direction. Transverse dunes run are a right angle to the constant wind direction. Star dunes are star-shaped and have several ridges that spread out around a point. Oases are vegetated areas moistened by springs, wells, or by irrigation. Many are artificial. Oases are often the only places in deserts that support crops and permanent habitation.

Soils

irrigation Soils that form in arid climates are predominantly mineral soils (classified as Aridisols) with low organic content such as salt. The repeated accumulation of water in some soils causes distinct salt layers to form. Calcium carbonate precipitated from solution may cement sand and gravel into hard layers called "calcrete" that form layers up to 50 meters thick. Caliche is a reddish-brown to white layer found in many desert soils. Caliche commonly occurs as nodules or as coatings on mineral grains formed by the complicated interaction between water and carbon dioxide released by plant roots or by decaying organic material.

Vegetation

Most desert plants are drought- or salt-tolerant, such as xerophytes. Some store water in their leaves, roots, and stems. Other desert plants have long tap roots that penetrate the water table, anchor the soil, and control erosion. The stems and leaves of some plants lower the surface velocity of sand-carrying winds and protect the ground from erosion. Deserts typically have a plant cover that is sparse but enormously diverse. The Sonoran Desert of the American Southwest has the most complex desert vegetation on Earth. The giant saguaro cacti provide nests for desert birds and serve as "trees" of the desert. Saguaro grow slowly but may live 200 years. When 9 years old, they are about 15 centimeters high. After about 75 years, the cacti develop their first branches. When fully grown, saguaro are 15 meters tall and weigh as much as 10 tons. They dot the Sonoran and reinforce the general impression of deserts as cacti-rich land. Although cacti are often thought of as characteristic desert plants, other types of plants have adapted well to the arid environment. They include the pea family and sunflower family. Cold deserts have grasses and shrubs as dominant vegetation.

Water

sunflower Rain does fall occasionally in deserts, and desert storms are often violent. A record 44 millimeters of rain once fell within 3 hours in the Sahara. Large Saharan storms may deliver up to 1 millimeter per minute. Normally dry stream channels, called arroyos or wadis, can quickly fill after heavy rains, and flash floods make these channels dangerous. Though little rain falls in deserts, deserts receive runoff from ephemeral, or short-lived, streams fed by rain and snow from adjacent highlands. These streams fill the channel with a slurry of mud and commonly transport considerable quantities of sediment for a day or two. Although most deserts are in basins with closed, or interior drainage, a few deserts are crossed by 'exotic' rivers that derive their water from outside the desert. Such rivers infiltrate soils and evaporate large amounts of water on their journeys through the deserts, but their volumes are such that they maintain their continuity. The Nile River, the Colorado River, and the Yellow River are exotic rivers that flow through deserts to deliver their sediments to the sea. Lakes form where rainfall or meltwater in interior drainage basins is sufficient. Desert lakes are generally shallow, temporary, and salty. Because these lakes are shallow and have a low bottom gradient, wind stress may cause the lake waters to move over many square kilometers. When small lakes dry up, they leave a salt crust or hardpan. The flat area of clay, silt, or sand encrusted with salt that forms is known as a playa. There are more than a hundred playas in North American deserts. Most are relics of large lakes that existed during the last ice age about 12,000 years ago. Lake Bonneville was a 52,000-square-kilometer lake almost 300 meters deep in Utah, Nevada, and Idaho during the Ice Age. Today the remnants of Lake Bonneville include Utah's Great Salt Lake, Utah Lake, and Sevier Lake. Because playas are arid land forms from a wetter past, they contain useful clues to climatic change. When the occassional preticipation does occur, it erodes the desert rocks quickly and powerfully. Wind is the other factor that erodes deserts- they are constant yet slow. The flat terrains of hardpans and playas make them excellent race tracks and natural runways for airplanes and spacecraft. Ground-vehicle speed records are commonly established on Bonneville Speedway, a race track on the Great Salt Lake hardpan. Space shuttles land on Rogers Lake Playa at Edwards Air Force Base, California.

Mineral resources

Some mineral deposits are formed, improved, or preserved by geologic processes that occur in arid lands as a consequence of climate. Ground water leaches ore minerals and redeposits them in zones near the water table. This leaching process concentrates these minerals as ore that can be mined. Evaporation in arid lands enriches mineral accumulation in their lakes. Playas may be sources of mineral deposits formed by evaporation. Water evaporating in closed basins precipitates minerals such as gypsum, salts (including sodium nitrate and sodium chloride), and borates. The minerals formed in these evaporite deposits depend on the composition and temperature of the saline waters at the time of deposition. Significant evaporite resources occur in the Great Basin Desert of the United States, mineral deposits made forever famous by the "20-mule teams" that once hauled borax-laden wagons from Death Valley to the railroad. Boron, from borax and borate evaporites, is an essential ingredient in the manufacture of glass, ceramics, enamel, agricultural chemicals, water softeners, and pharmaceuticals. Borates are mined from evaporite deposits at Searles Lake, California, and other desert locations. The total value of chemicals that have been produced from Searles Lake substantially exceeds US$1 billion. The Atacama Desert of South America is unique among the deserts of the world in its great abundance of saline minerals. Sodium nitrate has been mined for explosives and