Irreversible Thermodynamics of Cosmological Matter Creation

In this paper, we derive the expression of the internal energy of the universe, and we then study the physics of the very early universe from a thermodynamic point of view. In the process, we obtain interesting new physics about the actual time frames of the known key stages of the evolution of the universe in relation to the entropy of the universe. This then has the implication for the understanding of cosmology as we know it, and in particular the time frame of the large-scale structure formation as pointed out in the recent results from the James Webb Space Telescope (JWST). We complete the paper by studying the isothermal irreversible expansion of the universe and thus obtain the relation between irreversible particle creation and the Hubble parameter.