  At the early stage of the Universe-evolution there were no stars and no
galaxies, but only a uniform hot plasma consisting of free electrons and free
nuclei. The Universe temperature was determined by the Stefan-Boltzmann law of
thermodynamics and the general relativistic cosmological theory. At the present
time one has the background cosmic radiation with the temperature of 2.73K. We
calculate how much of the early Universe energy has gone to matter and other
forms of energy, so as to leave us with a background radiation of only 2.73K.
