There are reasons, increasing in number and quality, to believe that the masses of ordinary galaxies may have been underestimated by a factor of 10 or more.
Jeremiah P. OstrikerThere's no observational evidence that I know of that indicates electric and magnetic forces are important on cosmological scales.
Jeremiah P. OstrikerIf you take a galaxy and try to make it bigger, it becomes a cluster of galaxies, not a galaxy. If you try to make it smaller than that, it seems to blow itself apart.
Jeremiah P. Ostriker