Ancient astronomers knew that the stars move across the sky keeping together in the same fixed patterns. We call these patterns constellations. In the course of a twenty-four hour period, the constellations return to approximately their original place.
These astronomers were also aware that there were some stars that did not stay in fixed positions relative to the other stars. Instead, from night to night, they seemed to wander about the sky, following peculiar loop-the-loop paths of their own, while the rest of the stars formed a fixed background to their dancing.
The word for these wandering stars that we use now came to us from the Ancient Greeks, who used their own word for wanderer,
(planetes)
or planet.
And that’s why planets are called planets.
