“precession”的概念、定义、翻译、参考文献-科学参考

precession

Astronomy

The wobbling motion of a spinning top or gyroscope in which the axis of rotation gradually sweeps out a conical shape. The spinning Earth undergoes a slow precession, due to the combined gravitational attractions of the Sun, Moon, and planets. The Earth’s pole takes about 25 800 years to describe one complete circle on the celestial sphere; this circle has a radius of approximately 23°.5, i.e. the inclination of the Earth’s axis. The equinoxes make one circuit of the ecliptic in the same time. As a result of precession, the right ascension and declination of stars change with time, so the date or epoch for which these coordinates apply must always be stated. See also lunisolar precession; planetary precession; precession of the equinoxes.

Geology and Earth Sciences

The action of a couple whose axis is perpendicular to the rotational axis (a torque) on a rotating body causing its axis of rotation to trace out a path about an average position, instead of having a constant alignment, i.e. the axis of rotation itself revolves conically about a central point. The Earth’s axis of rotation precesses as a result of several forces, e.g. changes in mass distribution on its surface, changes in the gravitational field due to changes in the relative positions of the Moon, Sun, and planets, etc.

Geography

The wobbling of the Earth on its polar axis, which has a return period of 26000 years. This change in movement and orientation alters the amount and location of solar radiation reaching the Earth.

单词	precession
释义	precession Astronomy The wobbling motion of a spinning top or gyroscope in which the axis of rotation gradually sweeps out a conical shape. The spinning Earth undergoes a slow precession, due to the combined gravitational attractions of the Sun, Moon, and planets. The Earth’s pole takes about 25 800 years to describe one complete circle on the celestial sphere; this circle has a radius of approximately 23°.5, i.e. the inclination of the Earth’s axis. The equinoxes make one circuit of the ecliptic in the same time. As a result of precession, the right ascension and declination of stars change with time, so the date or epoch for which these coordinates apply must always be stated. See also lunisolar precession; planetary precession; precession of the equinoxes. Geology and Earth Sciences The action of a couple whose axis is perpendicular to the rotational axis (a torque) on a rotating body causing its axis of rotation to trace out a path about an average position, instead of having a constant alignment, i.e. the axis of rotation itself revolves conically about a central point. The Earth’s axis of rotation precesses as a result of several forces, e.g. changes in mass distribution on its surface, changes in the gravitational field due to changes in the relative positions of the Moon, Sun, and planets, etc. Geography The wobbling of the Earth on its polar axis, which has a return period of 26000 years. This change in movement and orientation alters the amount and location of solar radiation reaching the Earth.
随便看	tail, cometary tail end tail gas tailgating tailings tailings dam taille tailrace tails Taiping Rebellion (1850–64) Taitai Taiwan Taiyuan Launch Centre Taizong (596–649) Tajikistan takahe Takamine, Jokichi Takayama test take-off takeover takeover bid take-up rate talc anneal annealing