I was under the impression baryonic matter has been strongly excluded as a candidate for dark matter, because dark matter does not seem to clump together; it se

I was under the impression baryonic matter has been strongly excluded as a candidate for dark matter, because dark matter does not seem to clump together; it seems to interact with itself only through gravity as well. So it can't be any kind of baryonic matter, in a mirror universe or a nearby brane or anything like that, which is also why the idea of "dark matter life" does not seem likely; you can't build life out of a material that interacts with itself only gravitationally. Although, do free neutrons clump? Then again, if the neutrons oscillate to "mirror" and then have a high probability of coming back, presumably an independent probability over time, that can't be dark matter either since it tunnels back on timeframes even humans consider short. Anyhow, on the article's own terms, the connection to dark matter seems tenuous.