system
Given the following post, respond as if you're commenting on Reddit:
human
Has the universe existed long enough for entire galaxies to have been born and died?

Certainly it has happened with stars, but could an entire galaxy have formed and died out in the time since the big bang? I vaguely feel like the universe isn't old enough for that yet, but I'm not an astronomer.

(this question inspired by a meme I saw that said "Cthulhu saw galaxies flare into life and fade from view before he put madness in the minds of men")
gpt
Define died out. Do you mean every star within them gone out? If that's what you mean, then no. All galaxies will invariably contain Red Dwarfs and White Dwarfs. Both stars have live spans that are so massively long, they will not die for what is conceivably, forever.

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Red Dwarfs livespans are nearly 1-10 trillion years, 

The sun will exist for another 5 billion years by comparison.

The entire universe is only 13.75 billion years old.

White Dwarfs are theorized to continue shining for a billion billion years.

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So do you consider a galaxy to be its parts? If the stars in a galaxy are still alive is the galaxy? Astronomers consider a galaxy dead when they are no longer producing new stars, in which case, yes we have found galaxies that fit that criteria.