What are the regions or zones of the Earth?
The regions north of the Arctic Circle and south of the Antarctic Circle are called the Polar Regions or frigid zones.
The region between the Tropic of Cancer and the Tropic of Capricorn is called the Torrid Zone. The regions between the Tropic of Cancer and the Arctic Circle and between the Tropic Capricorn and the Antarctic Circle are called the north and south temperate zones respectively.
What are the polar ice caps?
Extremely cold temperatures of the Polar Regions cause ice formation on land and sea, resulting in a permanent blanket of ice around the poles called the polar ice caps.
What is the astronomical definition of ‘Day’?
Almost every heavenly body (including the Sun, Earth and planets) spins around its ‘axis of rotation’, which is an imaginary line passing through the geographic poles, around which the body rotates. The time taken by the body to rotate once around its axis astronomically defined as a ‘Day’.
In the case of the Earth, the astronomical day also known as sidereal day is 23 hours 56 minutes and 4 seconds. The astronomical day does not differentiate ‘day’ and ‘night’ and is independent of the position of the Sun in the sky.