Definition of nutation 1 archaic : the act of nodding the head. 2 : oscillatory movement of the axis of a rotating body (such as the earth) : wobble. 3 : a spontaneous usually spiral movement of a growing plant part.

Does Earth undergo nutation?

In the case of Earth, the principal sources of tidal force are the Sun and Moon, which continuously change location relative to each other and thus cause nutation in Earth’s axis. The largest component of Earth’s nutation has a period of 18.6 years, the same as that of the precession of the Moon’s orbital nodes.

How often does nutation occur on Earth?

As the relative positions and distances from the earth to the sun, moon, and planets vary, so does the rate of precession. The only variation of importance in navigation is nutation. Nutation is a nodding of the poles, one oscillation occurring in about 18.6 years.