北极星[North Star] - 达人(其实～我是卧底，来自外星)

2005/08/13 | 北极星[North Star]
类别(¤〖天文〗) | 评论(0) | 阅读(36) | 发表于 15:22: The North Star is a star located close to the North Pole of the celestial sphere, i.e., the projection of the North Pole onto the sky. The North Star is current Polaris (right ascension [img]http://scienceworld.wolfram.com/astronomy/nimg21.gif[img], declination ) since it is closest to the north celestial pole. However, due to precession of the equinoxes, the pole rotates through the sky with a period of about 26,000 years. Consequently, Vega (,) will become the North Star in ten to twelve thousand years.; 0