Could dark matter be invisible bound states of ordinary matter or ehm, aliens?
I've thought about dark matter and I'm wondering if it could possible be made up invisible bouond states of ordinary matter? Wikipedia says "According to consensus among cosmologists, dark matter is composed primarily of a new, not yet characterized, type of subatomic particle." But why a totally new particle? Maybe some selection of known fundamental particles can arrange themselves in an undiscovered way such that they are bound to eachother but do not emit or absorb light. Has this possibility been considered? If so, what were the results?
Also when thinking about this, I realized that the invisible bound states (or IBS as I would name them hehe) could pair up with other IBS much like atoms pair up with other atoms to form molecules. So there might be a totally different class of matter and maybe even life in deep space.
This is of course very exotic and speculative and I'm actually expecting someone to come and explain why it's all rubbish. But I would be interested in knowing if anyone else has sugested such an explanation and if there are any articles or something about it.