On Origins Galaxies, Stars, Life

Abstract

This chapter shows application of a consistent set of clear physical principles to describe the beginnings of the universe by the (hot) Big Bang model. The ultimate beginning presents difficulties for the physicist, particularly when it comes to explaining why we find a very inhomogeneous cosmos, instead of a uniform, radiating gas. Stars, globular clusters, galaxies, and clusters of galaxies dot space, but we cannot at present explain their presence without invoking a “deus ex machina.” We expect ultimately to rationalize the existence of these local inhomogeneities through gravitational contractions of regions of higher than average mass density that in turn arise out of fluctuations, but the case cannot yet be made completely. Meanwhile, the Big Bang (incomplete) model deals with cosmic evolution in the large, as a balance between gravitational attraction and cosmic expansion. Its relationships are described by two simple equations derived from Einstein’s theory of general relativity via local conservations of mass-energy and of momentum. Unfortunately, this model does not by itself produce the observed inhomogeneities. Neither the assumption of thermodynamic fluctuations following a “smooth” beginning nor that of a chaotic beginning can itself account for stars and galaxies. A mystery remains. —The Editor