Arctic_Circle

{{for|the fast food restaurant chain|Arctic Circle Restaurants}}
[[Image:World map with arctic circle.jpg|thumb|350px|World map showing the Arctic Circle in red]]
[[Image:Arctic Circle sign.jpg|thumb|right|200px|A sign along the [[Dalton Highway]] marking the location of the Arctic Circle in Alaska.]]
The '''Arctic Circle''' is one of the five major [[circle of latitude|circles of latitude]] that mark maps of the [[Earth]]. It is the parallel of [[latitude]] that (as of 2000) runs 66[[degree (angle)|°]] 33′ 39″ (or 66.56083[[degree (angle)|°]]) north of the [[Equator]]. The region north of this circle is known as the [[Arctic]], and the zone just to the south is called the [[temperate|Northern Temperate Zone]]. The equivalent latitude in the southern hemisphere is called the [[Antarctic Circle]].

The Arctic Circle marks the southern extremity of the [[midnight sun|polar day]] (24 hour sunlit day, often referred to as the "midnight sun") and [[polar night]] (24 hour sunless night). North of the Arctic Circle, the [[sun]] is above the [[horizon]] for 24 continuous [[hour]]s at least once per [[year]], and below the horizon for 24 continuous hours at least once per year. On the Arctic Circle these events occur, in principle, exactly once per year, at the June and December [[solstice]]s respectively. It is called the Arctic because it is corresponds to the southernmost point of the Constellation [[Ursa Major]] (the Great Bear or ''Megale Arktos'' in Greek).

In fact, because of [[atmospheric refraction]] and because the sun appears as a disk and not a point, part of the midnight sun may be seen on the night of the summer solstice up to about 50[[Minute|′]] (90 km) south of the Arctic Circle; similarly, on the day of the winter solstice part of the sun may be seen up to about 50′ north of the Arctic Circle. This is true at sea level; these limits increase with elevation above sea level, although in mountainous regions there is often no direct view of the horizon.

The position of the Arctic Circle is not fixed, but varies in a complex manner over time; see [[circle of latitude#Movement of the Tropics and the Arctic and Antarctic circles|''circles of latitude'']] for information.

==Geography and demographics==
The geography north of the Arctic Circle is predominantly [[Arctic Ocean|ocean]], mostly [[Sea ice|ice-covered]], but a great deal of land falls within the Circle as well. The Circle itself in fact passes through eight countries. From the [[Prime Meridian]] heading eastwards these are:

* [[Norway]]
* [[Sweden]]
* [[Finland]]
* [[Russia]]
* [[United States]] – [[Alaska]]
* [[Canada]]
* [[Greenland]], a territory of [[Denmark]]
* [[Iceland]] – crosses the island of [[Grímsey]]

Very few people live north of the Arctic Circle due to the cold conditions. The three largest towns above the Arctic Circle are situated in Russia; [[Murmansk]] (population 325,100), [[Norilsk]] (135,000), and [[Vorkuta]] (85,000). [[Tromsø]] in Norway has about 62,000 inhabitants, whereas [[Rovaniemi]] in Finland — which lies slightly south of the line — has slightly fewer than 58,000.

Recently the region north of the Arctic Circle has gained significant international attention due primarily to the perceived threat of [[global warming]]. Initial attention came as a result of the fact that the [[Geographical pole|earth's poles]] are the points at which the planet tends to warm the fastest thereby acting as harbingers of what is to come. The melting of the ice in the Circle is making the [[Northwest Passage]], the shipping routes through the northern-most latitudes, more navigable, raising the possibility that some day the Arctic region could become a prime trade route.<ref>''Will ice melt open fabled Northwest Passage?'', CNN.com, 29 Aug, 2002[http://archives.cnn.com/2002/TECH/science/08/29/northwest.passage/]</ref> In addition it is believed that the Arctic seabed may contain substantial [[oil field]]s which may become accessible if the ice covering them melts.<ref>''The great Arctic Circle oil rush'', CNN.com, 8 Aug, 2007[http://money.cnn.com/2007/08/07/news/international/arctic_oil.fortune/index.htm?postversion=2007080810]</ref> These factors have led to recent international debates as to which nations can claim sovereignty or ownership over the waters north of the Circle.<ref>''Russia stakes its claim on North Pole in underwater search for oil'', Times Online, 28 July, 2007[http://www.timesonline.co.uk/tol/news/world/europe/article2155477.ece]</ref>

==See also==
*[[Antarctic Circle]]
*[[Arctic haze]]
*[[Arctic Ocean]]
*[[Axial tilt]]
*[[Equator]]
*[[Northern Sea Route]]
*[[Solstice]]
*[[Territorial claims in the Arctic]]
*[[Tropic of Cancer]]
*[[Tropic of Capricorn]]

==References==

{{reflist}}
{{refimprove|date=December 2006}}

==External links==
{{Wiktionary}}
*[http://www.bugbog.com/images/maps/arctic_circle_map.jpg Topographical map of Arctic Circle, centered about North Pole]
*[http://www.world-maps.co.uk/maps/600-arctic.jpg Map of Arctic Circle (dotted line), showing major population areas]
*[http://www.mccord-museum.qc.ca/en/keys/webtours/GE_P3_5_EN.html Terra Incognita: Exploration of the Canadian Arctic] — Historical essay about early expeditions to the Canadian Arctic, illustrated with maps, photographs and drawings
*[http://foto.mail.ru/mail/dalm2000/arctic/ Collection of Arctic Circle borders ]

[[Category:Arctic]]
[[Category:Geography of Nunavut]]
[[Category:Geography of the Northwest Territories]]
[[Category:Lines of latitude]]
[[Category:Arctic Ocean]]

[[br:Kelc'h Arktika]]
[[bg:Северен полярен кръг]]
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[[es:Círculo polar ártico]]
[[eo:Arkta Cirklo]]
[[eu:Zirkulu Polar Artikoa]]
[[fr:Cercle Arctique]]
[[gl:Círculo Polar Ártico]]
[[hr:Polarni krugovi]]
[[he:חוג הקוטב]]
[[nl:Noordpoolcirkel]]
[[ja:北極圏]]
[[no:Nordlige polarsirkel]]
[[pl:Koło podbiegunowe]]
[[pt:Círculo Polar Ártico]]
[[ru:Полярный круг]]
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