Formation of the Tropic and Arctic Circle

The formation of the tropic and polar circles is related to the inclination of the earth's axis.

The emergence of the tropics

• The earth is known to move around the sun and rotate in the process. However, it is not perpendicular to its orbit, but is inclined at 23 ° 26'16 "to it.
• The tropics are at 23 ° 26'16 "north and south latitudes. They designate the outermost circles of latitude on which the vertical position of the sun above the earth is possible, namely on the two days of the solstice. At the (European) summer solstice, the sun is at its zenith on the tropic in the north, at the (European) winter solstice on the south. Of course, the sun can also be vertical in the area between the two tropics.
• In fact, the tropics change very slowly due to the change in the earth's axis and are currently approaching the equator.

This creates an arctic circle

The formation of the polar circles is also related to the sun and the earth's axis.

• The polar circles are the same distance from the poles as the tropics are from the equator. They are each located at 66 ° 34 'north or north. southern latitude.
• The polar circles describe the latitude at which the sun does not rise or does not rise for a whole day at the winter solstice. at the summer solstice it just doesn't go down for a whole day.
• The further you go from the polar circles towards the Pole, the longer the time of nightless resp. dayless days. Finally, on the poles, there is half a year of darkness and half a year of light.
• Since the change in the earth's axis also affects the polar circles, these are currently slowly moving towards the poles.