Just today I heard a talk about people looking at stellar motions in ultra faint dwarf galaxies, because standard dark-model theories predict they should have centrally cusped dark-matter density profiles -- and fuzzy dark-matter models predict different profiles, which they could potentially discriminate between.
However, it is very much true that different galaxies have different amounts and distributions of dark matter. There are many broad categories, and certain models about galaxy formation try to predict these, but not all galaxies fit these models. This has two effects: for one, for any galaxy with unexpected dynamics, you can fit a dark matter distribution to explain the dynamics (but! This is not unbounded, it still has to match certain other observations). The other effect is actually in favor of a dark matter approach: it means modifying parameters of our theories in a general way has little chance to reproduce the same properties, as each different galaxy is different.
> Then again, almost no one with a formal education in cosmology or partical physics at the PhD level does.
This is also just wrong. I think we're seeing a number of established voices starting to question the underpinnings of dark matter as a theory.
As for
>Which additional complexity has been added to dark matter?
Let's start with the fucking article we're discussing, where we now need to have "self-interacting" dark matter, as a new spin on the theory to account for the forces needed to explain what we're observing...
The article is also not adding complexity. We didn't get new evidence that required modification of DM. We got a phenomenon which has many potential explanations as the "fucking" article points out, one of which could be a subset of all DM theories. The final parsec problem isn't challenging DM at all, instead one particular flavor of DM could help explain the observation. If anything, it could constrain DM. Why wouldn't you explore this possibility?
We didn't get any new evidence that required modification of epicycles! We got a phenomenon which constrains the epicycle theory by adding more circles! <-- you.
> If anything, it could constrain DM. Why wouldn't you explore this possibility?
You're the only one suggesting that we throw out DM as a model right now... at no point have I even hinted at not exploring it. You are bashing someone who is simply suggesting that this model might not be correct (how fucking dare I...).
But the thing about models... no model is correct, but some models are useful.
Again - I'm not contesting that DM is currently a useful model for explaining some of things we're seeing. I'm suggesting that it might also be worth considering alternatives (how fucking dare I...).
Go back to trying to burn Galileo alive. It's the same energy.