Mercury the planet moves pretty quickly, visibly changing its position relative to the background stars even after a single night.

水星的移动速度非常快，甚至一个晚上就可以看到它和背景星系的相对位置发生了明显的变化。

A lot of other phenomena could masquerade as planets, like starspots, or pulsating stars, or background stars messing up the measurements.

许多其他的天文现象也可能伪装成行星，比如恒星黑子，或脉动的恒星，或隐藏恒星扰乱了测量。