Search results
Results From The WOW.Com Content Network
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. [1]
The maximum radius of this ellipse is the constant of nutation, approximately 9.2 arcseconds. Smaller effects also contribute to nutation. These are caused by the monthly motion of the Moon around the Earth and its orbital eccentricity, and similar terms caused by the annual motion of the Earth around the Sun.
A motion in which the second Euler angle changes is called nutation. In physics , there are two types of precession: torque -free and torque-induced. In astronomy, precession refers to any of several slow changes in an astronomical body's rotational or orbital parameters.
Earth's rotation axis moves with respect to the fixed stars (inertial space); the components of this motion are precession and nutation. It also moves with respect to Earth's crust; this is called polar motion. Precession is a rotation of Earth's rotation axis, caused primarily by external torques from the gravity of the Sun, Moon and other bodies.
The full explanation for the period also involves the fluid nature of the Earth's core and oceans—the wobble, in fact, produces a very small ocean tide with an amplitude of approximately 6 mm (1 ⁄ 4 in), called a pole tide, which is the only tide not caused by an extraterrestrial body.
Periodic motions of the Moon and of Earth in its orbit cause much smaller (9.2 arcseconds) short-period (about 18.6 years) oscillations of the rotation axis of Earth, known as nutation, which add a periodic component to Earth's obliquity. [22] [23] The true or instantaneous obliquity includes this nutation. [24]
Precessional movement of Earth. Earth rotates (white arrows) once a day around its rotational axis (red); this axis itself rotates slowly (white circle), completing a rotation in approximately 26,000 years [1] In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical body's rotational ...
The gravitational attraction of the Sun and Moon on the Earth's equatorial bulge cause the rotational axis of the Earth to precess in space similar to the action of a top. This is called precession. Nutation is the smaller amplitude shorter-period (< 18.6 years) wobble that is superposed on the precessional motion of the Celestial pole. It is ...