1、Newton for years had been curious about the cause of the orbital motion of the moon and planets.
多年來，牛頓一直對月球和行星繞軌道運行的原因感到好奇。

2、For years Newton had been curious about the cause of the orbital motion of the moon and planets.
多年來，牛頓一直對月球和行星軌道運動的成因好奇。

3、Orbital motion about a point, especially as distinguished from axial rotation.
旋轉，繞轉：圍繞一個點的軌道運動，尤指區(qū)別于繞軸旋轉的。

4、orbital motion of lunar probe
月球探測器軌道運動

5、Here, the gravitational waves emitted from the orbital motion in the mHz range would be detectable.
在LISA上面，這些軌道運動所發(fā)出的兆赫茲范圍的引力波都可以被探測到。