system
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human
If dark matter generates a gravitational field, and dark matter can 'clump' like ordinary matter, can dark matter collapse under its own weight like regular matter to make a dark-black hole?

Sorry if the question is poorly formed. I was just recalling something about dark matter; something about a 6:1 relationship to regular matter, and was wondering whether dark matter amasses like regular matter does; capable of making 'dark-planets', 'dark-stars' or even 'dark-black holes', if such a thing is even intelligible by the lights of modern physics.
gpt
> dark matter can 'clump' like ordinary matter

No, it cannot.

Regular matter - there's gravitational attraction, and then there's friction (collisions) between particles. Gravity pulls everything together, and then friction slows particles down (relative speed decreases) so that they can "clump" together. This is how you get planets, asteroids, etc.

Dark matter - truth be told, we don't know much about it, but it does not appear to experience friction as far as we can tell, either with itself or with regular matter. For that reason, it will probably never make "clumps". Particles of dark matter (if they exist as such) will be drawn together by gravity, but then they will just zoom right past each other.

I did some numeric simulations for particle collectives under mutual attraction, years ago. Without friction, it's just a big swarm that keeps roiling over and over. Kind of fun to watch, but it doesn't really do anything.

With dark matter, you may get such swarms arbitrarily big, maybe as big as a galaxy. This is because the only significant interaction that DM seems capable of is gravity; there might be exceptions, but those are probably exceedingly rare (some experiments are being worked on to hunt for such rare occurrences).

If DM falls into an existing black hole, it's likely that the BH won't treat it any different from regular matter. It gets swallowed up, and its mass is added to the BH. But this is a bit speculative, since we haven't seen DM from up close.

TLDR: It doesn't clump.