what is the spinning of a planet of it's axis called
Earth's Rotation. Earth's Rotation and the Apparent Daily Motion of the Sky. The earth rotates about an imaginary line that passes through the North and South Poles of the planet. This line is called the axis of rotation. Earth rotates about this axis once each day (approximately 24 hours). Although you most likely already knew that fact, there is a slight complication most people are not aware of. More specifically, our rotation period (the time elapsed for one rotation) with respect to the stars is called a sidereal day. A sidereal day is 24 sidereal hours, or 23 hours and 56 minutes on a normal clock.