ABSTRACT

According to Chambers's Dictionary, cosmology is 'the science of the universe as a whole'. Again, it is customary to divide a subject into neatly-separated sections, even though this can obscure the richness of their interconnections. Nevertheless, it does help to distinguish three main aspects of cosmology. Firstly, it has cosmography: cataloguing the objects in the universe and charting their positions and motions. Secondly, there is theoretical cosmology, where it searches for a frame-work within which to comprehend the information from cosmography. The third aspect of cosmology is cosmogony; this is the study of the origin of the universe. Theoretical cosmology employs the physical laws established on and near the Earth, and makes the outrageous extrapolation that they apply throughout the universe. In simple terms, the cosmological principle says: 'There is nothing special, cosmologically, about the Earth; therefore our large-scale observations are the same as those which would be made by observers anywhere else in the universe'.