This thread is seeking help in finding authoritative sources regarding questions about dark matter (DM). It is motivated by the discussion in two other threads: https://www.physicsforums.com/threads/is-dark-matter-cold-or-warm.893111/ https://www.physicsforums.com/threa...all-baryonic-matter-is-in-black-holes.899275/ Here is what I think is well known. If this is wrong, I would appreciate being corrected. 1. There is approximately four times as much DM in the universe as ordinary matter. 2. This was learned from three sources. (a) Velocity profiles from the stars in galaxies (b) Estimates of ordinary matter density from visible sources. (c) finding the best fit solution to Friedmann equation (below) that fits astronomical red-shift and brightness data from distant supernovas. 3. Over a decade of investigations regarding the possibility that DM consists of WIMPs has so far been unsuccessful. 4. Not much else is known with any high degree of certainty. Here are a few questions to get started. 1. What is known about the distribution of DM surrounding a galaxy, if any? 2. If there is such knowledge, is this knowledge obtained from only velocity profiles or also from other methods? 3. Is the distribution known to be (a) close to being uniform, (b) non-uniform, but spherically symmetric or nearly so, (c) something else, or (d) unknown? Any responses will be much appreciated.