(Fiction warning): Riffing off that a bit, I think back to this illustration of spacetime - https://simple.wikipedia.org/wiki/Space-time#/media/File:GPB_circli

(Fiction warning): Riffing off that a bit, I think back to this illustration of spacetime - https://simple.wikipedia.org/wiki/Space-time#/media/File:GPB_circling_earth.jpg https://simple.wikipedia.org/wiki/Space-time#/media/File:GPB... - and imagine a black hole being a place where that fabric is punched through. as if spacetime is just resting on another universe. Where things get massive enough, they punch through and the matter begins to drain away. We don't know what the rate of flow is, though. I like this because referring back to the comment about not being able to see enough matter - we know black holes aren't massive enough to account for all the dark matter - but, what if the discrepancy of observation vs expectation gave us some idea of what the flow rate through black holes might be?