ABSTRACT
This chapter explores the relationship between particle energies, temperature and energy density. It discusses the inflationary universe, a hypothetical cosmological model which differs from standard conceptions and which could resolve many cosmological problems. It must however be stressed that the self-consistency of the model concepts presented by no means clear, and thus these concepts should only be viewed as a basic outline for a solution. The cosmological standard conception is that our universe was created in the so-called 'big bang' from a singular configuration of space and time. Another major problem of cosmology and elementary particle theory is baryon-antibaryon asymmetry or, more generally, matter-antimatter asymmetry. The chapter also discusses the heavy neutrinos predicted by the Grand Unification Theories (GUT) models. According to the standard conception, the enormously large particle energies, for which the GUT models predict startling new phenomena, existed as thermal energy for a very short time, at the birth of our universe.
