03/05/2013
On the map shown, and for that matter on all other maps, the Arctic Circle, Antarctic Circle, Equator, Prime Meridian, Tropic of Cancer and Tropic of Capricorn are imaginary lines.
ARCTIC CIRCLE: It is one of the five major circles of latitude that mark maps of the Earth. Its exact location varies slightly each year, and currently it's positioned at 66° 33′ 44″ (or 66.5622°) north of the Equator.
NOTE: The position of the Arctic and Antarctic Circles are not fixed, as their exact location depends on the Earth's axial tilt, which fluctuates within a margin of 2° over a 40,000 year period, mainly due to tidal forces resulting from the orbit of the Moon.
EQUATOR: Located at zero degrees latitude (North or South,) is 24,901.55 miles long and divides the Planet Earth into the Northern and Southern Hemispheres.
TROPICS OF CANCER AND CAPRICORN: Located at 23.5 degrees North and 23.5 degrees South of the Equator, this area of Planet Earth (between those two lines) is known as the "Tropics," and is colored with a lighter blue color on the globe. This area experiences no dramatic change in season because the sun is consistently high in the sky throughout the year.
PRIME MERIDIAN: Located at zero degrees longitude (East or West), it divides the Planet Earth into the Eastern and Western Hemispheres,and is the line from which all other lines of longitude are measured.
