Nutation - Wikipedia
Nutation (from Latin nūtātiō 'nodding, swaying') is a rocking, swaying, or nodding motion in the axis of rotation of a largely axially symmetric object, such as a gyroscope, planet, or bullet in flight, or as an intended behaviour of a mechanism.
Astronomical nutation - Wikipedia
Astronomical nutation is a phenomenon which causes the orientation of the axis of rotation of a spinning astronomical object to vary over time. It is caused by the gravitational forces of other nearby bodies acting upon the spinning object.
Nutation | Definition, Causes, Period, & Facts | Britannica
Nutation (Latin nutare, “to nod”) superimposes a small oscillation, with a period of 18.6 years and an amplitude of 9.2 seconds of arc, upon this great slow movement. The cause of nutation lies chiefly in the fact that the plane of the Moon’s orbit around Earth is tilted by 5.15° from the plane of Earth’s orbit around the Sun .
5.9: Precession and Nutation - Physics LibreTexts
2020年12月30日 · Due to the action of a second force (with associated torque), the angle between the angular momentum vector and the fixed axis (which we’ll call the z-axis) may also change, a process known as nutation.
6.8: Nutation - Physics LibreTexts
The nutation in longitude has an amplitude of \(17^{\prime \prime}.2\), and the nutation in the obliquity has an amplitude of \(9^{\prime \prime} .2\). In addition, planetary perturbations cause a secular (i.e. not periodic) decrease in the obliquity of about \(0^{\prime \prime}.47\) per year.
Nutation and Precession - NASA
2018年12月14日 · Nutation and precession are the periodic and long-term motion of the Earth's spin axis in space. The direction of the Earth's axis in space, shown in orange, changes over time with respect to extremely distant objects, such as quasars.
The motion consists of two parts, general precession and nutation. General precession carries the mean pole of the equator around the pole of the ecliptic in about 26,000 years and nutation carries the true pole around the mean pole in about 18.6 years. Thus the effect of precession is secular and the effect of nuta- tion is periodic.