Axial precession

Axial precession, also known simply as precession, refers to the gradual shift or change in the orientation of an astronomical body's rotational axis. For Earth, this means the slow movement of its rotational axis in a circular or elliptical path, which affects the position of the celestial poles over time. The main causes of axial precession are gravitational forces exerted by the Sun and the Moon on Earth's equatorial bulge.