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Arctic Circle

The Arctic Circle is one of the two polar circles, and the most northerly of the five major circles of latitude as shown on maps of Earth at about 66° 34' N.[1] Its southern equivalent is the Antarctic Circle.

This article is about one of the five major circles of latitude. For other uses, see Arctic Circle (disambiguation).

The Arctic Circle marks the southernmost latitude at which, on the Northern Hemisphere's winter solstice (which is the shortest day of the year), the Sun will not rise all day, and on the Northern Hemisphere's summer solstice (which is the longest day of the year), the Sun will not set. These phenomena are referred to as polar night and midnight sun respectively, and the further north one progresses, the more pronounced these effects become. For example, in the Russian port city of Murmansk, three degrees above the Arctic Circle, the Sun does not rise above the horizon for 40 successive days in midwinter.[2][3][4]


The position of the Arctic Circle is not fixed and currently runs 66°33′49.9″ north of the Equator.[5] Its latitude depends on the Earth's axial tilt, which fluctuates within a margin of more than 2° over a 41,000-year period, owing to tidal forces resulting from the orbit of the Moon.[6] Consequently, the Arctic Circle is currently drifting northwards at a speed of about 14.5 m (48 ft) per year.

Etymology[edit]

The word arctic comes from the Greek word ἀρκτικός (arktikos: "near the Bear, northern")[7] and that from the word ἄρκτος (arktos: "bear").[8]

Northern Polar Circle Globe on Vikingen island marking the Arctic Circle in Norway

Northern Polar Circle Globe on Vikingen island marking the Arctic Circle in Norway

Arctic Circle sign by the Inland Line railway, Sweden

Arctic Circle sign by the Inland Line railway, Sweden

The white borderline of the Arctic Circle at the Santa Claus Village in Rovaniemi, Finland

The white borderline of the Arctic Circle at the Santa Claus Village in Rovaniemi, Finland

Arctic Circle sign in the Republic of Karelia, Russia

Arctic Circle sign in the Republic of Karelia, Russia

Arctic Circle sign by the Yamalo-Nenets Autonomous Okrug, Russia

Arctic Circle sign by the Yamalo-Nenets Autonomous Okrug, Russia

A sign in the Sakha Republic (Yakutia), Russia

A sign in the Sakha Republic (Yakutia), Russia

Arctic Circle marker on island of Grímsey in Iceland

Arctic Circle marker on island of Grímsey in Iceland

—Historical essay about early expeditions to the Canadian Arctic, illustrated with maps, photographs and drawings

Terra Incognita: Exploration of the Canadian Arctic

Download: Epoch v2009.xls (modify D4)

Temporal Epoch Calculations ©2006 by James Q. Jacobs

See: Obliquity of the ecliptic

Useful constants"