“equinox”的概念、定义、翻译、参考文献-科学参考

equinox

Physics

1. Either of the two points on the celestial sphere at which the ecliptic intersects the celestial equator. The sun appears to cross the celestial equator from south to north at the vernal equinox and from north to south at the autumnal equinox.

2. Either of the two instants at which the centre of the sun appears to cross the celestial equator. In the northern hemisphere the vernal equinox occurs on or about March 21 and the autumnal equinox on or about Sept. 23. In the southern hemisphere the dates are reversed. See precession of the equinoxes.

Astronomy

Either of the two points at which the Sun’s apparent yearly path (the ecliptic) intersects the celestial equator; or the dates on which this occurs—on March 20 (vernal equinox) and September 22 or 23 (autumnal equinox). These points are also known as the first point of Aries and the first point of Libra. When the term ‘equinox’ is used without qualification, the vernal (spring) equinox is meant. Around the time of the equinoxes, night and day are equal in length the world over. The equinox is not a fixed point, but moves because of precession and nutation. If only precession is taken into account, the resulting point is known as the mean equinox of date. If, however, nutation is also included, the point is known as the true equinox.

Geography

Equinoxes, those times when day and night are of equal length, occur twice a year. The spring, or vernal, equinox is on 21 March and the autumn equinox is on 22 September. On these dates, the sun is directly overhead at the equator. The changes in day length result from the changes in the tilt of the Earth with respect to its axis.

单词	equinox
释义	equinox Physics 1. Either of the two points on the celestial sphere at which the ecliptic intersects the celestial equator. The sun appears to cross the celestial equator from south to north at the vernal equinox and from north to south at the autumnal equinox. 2. Either of the two instants at which the centre of the sun appears to cross the celestial equator. In the northern hemisphere the vernal equinox occurs on or about March 21 and the autumnal equinox on or about Sept. 23. In the southern hemisphere the dates are reversed. See precession of the equinoxes. Astronomy Either of the two points at which the Sun’s apparent yearly path (the ecliptic) intersects the celestial equator; or the dates on which this occurs—on March 20 (vernal equinox) and September 22 or 23 (autumnal equinox). These points are also known as the first point of Aries and the first point of Libra. When the term ‘equinox’ is used without qualification, the vernal (spring) equinox is meant. Around the time of the equinoxes, night and day are equal in length the world over. The equinox is not a fixed point, but moves because of precession and nutation. If only precession is taken into account, the resulting point is known as the mean equinox of date. If, however, nutation is also included, the point is known as the true equinox. Geography Equinoxes, those times when day and night are of equal length, occur twice a year. The spring, or vernal, equinox is on 21 March and the autumn equinox is on 22 September. On these dates, the sun is directly overhead at the equator. The changes in day length result from the changes in the tilt of the Earth with respect to its axis.
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