1Foundations of the New Cosmology
Cosmology is the study of the origin and evolution of the Universe as a whole. Nowadays, this is a subject with immense popular appeal. Hardly a day seems to go by without the media announcing a new discovery by astronomers using one of the bewildering array of high-tech instruments now at their disposal. This popular appeal has at least partly to do with the universal desire to understand where we came from, what the Universe is all about and why we are here. These are questions traditionally addressed by religions, and it may be that the amazing growth of interest in cosmology is related in some way to the decline of the religious tradition, at least in the Western world. But in any case, the task of unravelling the nature of the Universe using both sensitive observations of impossibly distant objects and complex, obscure mathematical theories is an ambitious goal indeed. And even those who do not understand the technicalities of the work being done can hardly fail to be impressed by the achievements of the 1990s. Cosmologists themselves often describe the current era as the ‘Golden Age’ of cosmology, with developments in instrumental technology making possible observations that could scarcely have been imagined in the previous decade. And significant breakthroughs in fundamental physics have led to important changes in the way we think about the Universe and how we interpret the new observational data.