Within our own galaxy there are probably tens of thousands of planetary systems.在我们所处的银河系中, 大概有数万个行星系。

satellite photographs of planetary surfaces卫星拍摄的行星表面照片

Marjorie Orr takes a look at the planetary influences likely to affect our lives in August.玛乔丽•奥尔看了看可能会在八月影响我们生活的星座运程。

The electrons moved in planetary orbits.电子在绕原子核轨道上运动。