Nutation is a small, periodic oscillation in the orientation of an astronomical body, such as the Earth. It occurs due to gravitational forces exerted by the Moon and the Sun on the Earth's equatorial bulge. This motion causes the axis of the Earth to wobble slightly, leading to variations in the position of celestial objects over time. The nutation cycle lasts about 18.6 years and is superimposed on the longer-term precession of the Earth's axis. This phenomenon affects the timing of seasons and can influence astronomical observations. Understanding nutation is essential for precise navigation and satellite positioning.