Cosmology Solved?

Abstract

For two decades the hot big-bang model as been referred to as the standard cosmology -- and for good reason. For just as long cosmologists have known that there are fundamental questions that are not answered by the standard cosmology and point to a grander theory. The best candidate for that grander theory is inflation + cold dark matter; it can extend our understanding of the Universe back to 10^-32 sec. There is now prima facie evidence for the two basic tenets of this new paradigm: flat Universe and scale-invariant spectrum of Gaussian density perturbations, and an avalanche of telling cosmological observations is coming. If inflation + cold dark matter is correct, then there are new, fundamental questions to be answered, most notably the nature of the dark energy that seems to account for 60% of the critical density and how inflation fits into a unified theory of the forces and particles. These are exciting times in cosmology!