The Earth has two motions – it spins on its axis and it moves in an orbit around the Sun.
The period of rotation through 360 degrees (that is one complete turn of the earth) takes 23 hours, 56 minutes and 4.091 seconds.
It was believed that the speed of rotation never changes. But, it has been found that there are tiny variations.
Because of the friction of ocean tides and changes in the earth’s crust, our day may be getting longer at the rate of about one thousandth’s of a seconds per century.
Earth’s orbit around the Sun is Elliptical and not Circular. A planet moves faster when it is closed to the sun and since the Sun doesn’t stay the same at all times, the orbital speed is constantly changing.
