system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How did ancient astronomers distinguish planets from stars?
gpt
The word "planet" means wanderer. When ancient astronomers looked at the night sky they noticed that most of the points of light were fixed in relation to each other. Each night the stars would all be in the same place as they moved across the sky. But, a few of the points of light would move from night to night. 

Over the course of weeks and months they would be in completely different positions. Sometimes, near this constellation, sometimes near that one. Sometimes they would rise just after dark, sometimes not until just before dawn.

Through these observations they realized these wanderers were a different type of object from the fixed stars.