Eli5: How could humans tell the difference between a planet and a star in the nightsky, before telescopes where invented?
In: Planetary Science
Planets were called “wandering stars” by the Greeks, who were among the cultures that noticed them move a little bit between the motionless stars night after night.
If you have for example Leo, and you notice a bright red star in it, a week later you can see it has changed positions compared to everything else in the layout of the stars, and you’re gonna consider it a different type of star altogether.
Also, planets don’t twinkle… not nearly as much as stars do, anyway.
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