Grand unified theories, galaxy formation and the large-scale structure of the universe

This paper reports on quantitative astronomical data which can only be explained using ideas from particle physics. In a class of theoretical models - those in which cosmic strings seed the density perturbations - there is observational evidence for new physics at the scale of grand unification, 1016 GeV. In cosmic string models (which are often based on grand unified theories) it is now possible to calculate many of the functions which can be measured observationally. Particular attention is drawn to the fact that neutrinos can be resurrected as a viable dark matter candidate provided the energy density perturbations are induced by cosmic strings