precession

Precession is the gradual wobbling or tilting of an object's rotational axis over time. Think of a spinning top: as it slows down, its axis tilts and circles around, creating a slow, conical motion. In Earth’s case, precession causes the North Star to change over thousands of years, as Earth's axis slowly wobbles in a circle. This occurs because of gravitational forces from the Sun and Moon acting on Earth's equatorial bulge, leading to a slow rotation of the axis. Precession affects climate cycles and astronomical observations over long periods.