system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 Why are different galaxies different colors?

I understand how different stars are different colors, and planets, and so-forth. But my thought process assumes the “law of averages” would make most galaxies at least close to the same overall color…..why aren’t they?
gpt
Redshift and blueshift factor in, too. Galaxies are all in motion. Some galaxies are coming towards us, some away from us, some at incredibly fast speeds. These relative motions compress or elongate the frequencies of the light coming from them, so they get pushed up the spectrum to red or down the spectrum to blue and violet, and everywhere in between.

Since this more or less applies to each given galaxy as a whole, for the most part, it would give lots of galaxies different apparent colors from our perspective on earth.