Parsec Wall光年长城
PARSEC CORPORATIONPARSEC公司
cubic parsec[天] 立方秒差距
mega-parsec百万秒差距
million-parsec百万秒差距
N(名词) a unit of astronomical distance equal to the distance from earth at which stellar parallax would be 1 second of arc; equivalent to 3.0857×1016 m or 3.262 light years 秒差距; 测量天体间距离的单位