While dark matter may comprise 95% of the matter content of the universe, its actual density in the region of the Solar System is much less than the density of ordinary matter. That's because the ordinary matter is mostly in the galactic disk while the dark matter is spread out in a spherical halo larger than the galaxy.The other part I mentioned was that dark matter is weakly interacting. I think your comments about equipartition are what I was getting at, although I didn't understand what you were saying.
Not to belabor the point its simply the naive notion that if gravity controls everything on the astro scale and we start off w/an uniform distro of dark and normal matter (i.e. not on the scale of the cosmological anisotropy) why do we end up w/ the "halo" of dark matter surrounding normal matter (since gravity one would think is the only thing doing the "attraction" on this scale). That is what difference does the EM forces make on the scale of star formation? since stars are so big and even EM forces die out pretty quickly. i.e. how does weak/no coupling w/ the other forces make any difference on the scale of stars) The answer must be equipartition..
I dont know enough (anything to be honest) about particle physics but somewhat unsurprisingly Wilzcek likes axions as the primary dark matter candidate. Well this conversation has inspired me to read some of these review articles aka the High Energy Physics ones as somewhat nerdy incomphrensible bed time reading:)
Slashdot Mirror
While dark matter may comprise 95% of the matter content of the universe, its actual density in the region of the Solar System is much less than the density of ordinary matter. That's because the ordinary matter is mostly in the galactic disk while the dark matter is spread out in a spherical halo larger than the galaxy.The other part I mentioned was that dark matter is weakly interacting. I think your comments about equipartition are what I was getting at, although I didn't understand what you were saying.
Not to belabor the point its simply the naive notion that if gravity controls everything on the astro scale and we start off w/an uniform distro of dark and normal matter (i.e. not on the scale of the cosmological anisotropy) why do we end up w/ the "halo" of dark matter surrounding normal matter (since gravity one would think is the only thing doing the "attraction" on this scale). That is what difference does the EM forces make on the scale of star formation? since stars are so big and even EM forces die out pretty quickly. i.e. how does weak/no coupling w/ the other forces make any difference on the scale of stars) The answer must be equipartition..
I dont know enough (anything to be honest) about particle physics but somewhat unsurprisingly Wilzcek likes axions as the primary dark matter candidate. Well this conversation has inspired me to read some of these review articles aka the High Energy Physics ones as somewhat nerdy incomphrensible bed time reading
(posting from my gf's account)