1590s; see planet + -ary. Probably from Late Latin planetarius "pertaining to a planet or planets," but this is attested only as "an astrologer." Planetary nebula, so called for its shape, attested from 1785.
权威例句
1. Within our own galaxy there are probably tens of thousands of planetary systems.
在我们自己的星系里可能有数以万计的行星系。
2. These bands must introduce longitudinal asymmetry in the planetary albedo.
这些云带必定引起行星反照率的经向不对称性.
3. Very accurate predictious of planetary orbits require corrections to the central - field approximation.
想要非常准确地预言行星的轨道,就需要对中心场近似进行修正.
4. The sciences of planetary geology have benefited tremendously from these new finds.
行星地质科学从这些新发现中受益匪浅.
5. New discoveries about Uranus excited planetary astronomers in 1977.