Question? Could something like this explain "dark matter"? Like, is it possible that space is more full of matter than we think? Or is my understanding of dark matter just way off.
"Something like this" is one of the competing theories for what dark matter is, although I think the current consensus is that it cannot explain _all_ the dark matter effects, so there must be something else too.
My understanding is that at this point we're pretty sure that dark matter does not interact with the rest of the universe via anything but gravity: https://en.wikipedia.org/wiki/Bullet_Cluster
That's very unlikely to be the case (although I'm not a physicist). I think it's more likely that under "normal" conditions dark matter does not interact with the luminous matter except via gravity. However, under extraordinarily energetic conditions, it might have some interactions. I guess that's the hope behind people proposing larger and larger accelerators (like the successor to the LHC). The medium of a neutron star is probably more energetic than anything we can hope to create here on Earth in the next few hundred years. So, over there dark matter may interact with normal matter, and if we know what to look for we may be able to detect that. For example, maybe we see some unusual spectrum that cannot be explained with regular atoms from the regular periodic table. Who knows. From what I heard, what's going on inside a neutron star involves both quantum mechanics and generalized relativity, and we can't model that quite well, so it's very difficult to say if something weird being observed there is a result of dark matter interactions or simply a not yet understood effect of normal matter being subjected to very extreme conditions. Bottom line: being able to observe neutron stars could lead to a better understanding of matter.