Thermodynamics of the Early Universe in the Classical Hot-Big-Bang Picture

Abstract

The hot-big-bang picture emerges from a FL model, where the expansion factor R (t) approaches zero towards the limit (t → 0) of the cosmic time t. The presence of a uniform radiation field implies a “hot” singularity, i.e. an ever-increasing temperature as t → 0. (This is true as long as the constituent particles of the radiation background can be treated as non-interacting. There are model theories of elementary particles where the interactions limit the temperature to a maximum, finite value, which is, however, large when compared with the energy scales discussed in this chapter; cf. also Chap. 7.)

“The present universe is something like the old professor nearing retirement with his brilliant future behind him.”

A. Sandage (1984)