Cosmology

Abstract

It is arguable that the most important scientific discovery of the 20^th century is that one can discuss the whole universe in a rational way. After all, what could be more important than understanding everything that there is? The key technical tool which permits such a rational discussion is Einstein’s general theory of relativity. For the first time this theory provides us with the means to represent the layout of the universe in space and time in a manner which is also dynamically self consistent. Newtonian theory, with its emphasis on the fundamental role of world-wide inertial frames of reference, cannot do this. It is true that in the 1930’s so-called Newtonian models were constructed, bearing a close similarity to the relativistic models, but this was only possible if it was permitted for inertial frames centred on different points to be accelerating relative to one another. This is not strictly part of the Newtonian concept. Moreover, it was not possible to give a satisfactory discussion of the propagation of light in these Newtonian models, and since light (and radio waves) is the main tool of the astronomer in exploring the universe, this defect is catastrophic.