"Could dark matter be made up of all those undiscovered black holes?" IANAP(I am not a physicist). I have a pet theory relating to this that goes something lik

"Could dark matter be made up of all those undiscovered black holes?" IANAP(I am not a physicist). I have a pet theory relating to this that goes something like this, and please forgive the simplification: normal matter is "seeking" to return to its original state in the other/dark universe membrane which can only be done through black holes, so dark matter wouldn't be made of black holes, but black holes are the portal through which matter becomes dark matter. In my theory Gravity is actually only a second teir side effect of normal matter seeking to return to dark matter to some degree. I would guess a way to test this would be to measure dark matter emittance near black holes. I suspect it will be highly concentrated in the area.