In 1977, [[Stephen Weinberg]] observed that "the theory of the formation of galaxies is one of the great outstanding problems of astrophysics, a problem that today seems far from solution". Although the past two decades have seen considerable progress, many questions remain. <ref>http://www.nature.com/nature/journal/v400/n6741/full/400220a0.html</ref> | In 1977, [[Stephen Weinberg]] observed that "the theory of the formation of galaxies is one of the great outstanding problems of astrophysics, a problem that today seems far from solution". Although the past two decades have seen considerable progress, many questions remain. <ref>http://www.nature.com/nature/journal/v400/n6741/full/400220a0.html</ref> |