This is the name that an imaginary line of the parallel of the Earth receives, it is located in the arctic region of the same, specifically in latitude 66 ° 33´ 44´´, this line is crossing different countries, such as Canada, Russia, Finland, Denmark, Finland, Norway and Sweden, in the northern region of the Arctic Circle during the summer the sun does not set for at least one day and during the winter the opposite effect occurs, this phenomenon can be seen increased in quantity days as you go further from this line.
The Arctic Circle is the limit in the extreme south between the polar days of the summer solstice and the polar nights of the winter solstice, within this imaginary line on the day of the summer solstice the Sun does not set for a period of 24 consecutive hours, while on the winter solstice the sun will not rise for the same period of time.
The latitude of this region is established by the inclination of the axis of rotation of the planet earth with respect to the ecliptic (curved line where the Sun travels around the planet). Its angle is not consistent, since on the contrary it has a somewhat complicated movement which is related to several periods ranging from short to very long, an example of this is one of the cycles that has the longest period of duration and it consists of an approximate time of 41 years, with an extension of 2.4 ° which is equal to 267 kilometers in the most superficial part.
For its part, nutation (the name given to the oscillation movement of the terrestrial pole in relation to its location with the celestial sphere) is very similar to the movement made by the tops when they lose their power and therefore they are about to brake, said Oscillation causes the Earth's poles to move approximately 9 arc seconds every so often (18 and a half years) for this reason and due to this oscillation the inclination can be modified by approximately 280 meters in the crust during that period of time.
