| 1. | According to the equatorial coodinate position of the galactic centre being observed by astronomist , it is determined that the position of solar system on galactic orbit plane , the time of the solar system and the earth revolution around the galactic centre for a circle , may be 220 ma 以目前太阳系在银道面上的位置为起点,按照时间倒退,顺时针逆转做图,确定过去不同地质年代太阳系在银道面上的位置。 |