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Published on Aug 29, 2012
Did you ever wonder why there are nights and days, sunrise and sunsets? Why the moon disappears during the day and Sun during the night? To understand this, one has to first understand the different motions of the earth. Earth has two types of motion - rotation and revolution. Rotation is the circular motion of the object around its center. Revolution is the motion of a body around a fixed point or a line. Earth rotates around its axis and also revolves around the Sun. Rotation is the motion that causes day and night. Earth completes one full rotation every 24 hours. The part of the Earth that faces the Sun has day and the other part has night. It takes 365 and one fourth of a day to complete one revolution around the Sun. The rest of the 6 hours of one fourth of a day are added to the month of February. which has 29 days instead of 28 days during the Leap year.