Planetary astronomy is no longer just one branch of astronomy, but has spilled over other fields . 行星天文学已不再是天文学的一个分支，而是与其他学科结合在一起了。
Planetary nebulae are a type of isolated gaseous nebulae possessing a fair degree of bilateral symmetry . 行星状星云是一类孤立的气体星云，具有相当程度的双侧对称性。
Finding planets orbiting barnards star would increase our confidence that planetary systems are common . 对环绕巴纳德里旋转的行星的发现将会增强我们认为行星系是普遍存在的信念。
These tiny regions may be condensations in the interstellar gas where stars and planetary systems could be forming . 这些很小的区域可能是能够形成恒星或行星系统的星际气体中的一些凝聚体。
If one-third of the stars are single stars with planets, then planetary systems are born, on the average, every three years . 如果这些恒星中有三分之一是拥有行星的单星，那么平均每三年就会诞生一个行星系。
These monuments are on major planetary grid points 这些纪念碑是行星的主网格点。
. . . and some kind of shit is gonna hit the planetary fan 这星球就会有大麻烦了
Planetary terminator games - 4455 miniclip games 行星终结者小游戏- 4399小游戏
Design of composite material wheel of planetary rover 复合材料深空探测车车轮的设计
It is , after all , a planetary emergency 毕竟，这是一个事关星球的紧急情况。
