It likely is, we just can't detect it on such small scales. It would be a form of matter that interacts pretty much only via gravity, and since gravity is alrea

It likely is, we just can't detect it on such small scales. It would be a form of matter that interacts pretty much only via gravity, and since gravity is already 40 orders of magnitude weaker than the electromagnetic force we usually use to detect things, it's understandable that it is kinda hard to see.