Scenario of a constantly pulsating universe

It is shown that in certain physical conditions the complete system of gravitation equations leads to a scenario of the periodically pulsating Universe between states with maximal $\sim10^{66}$ g/sm$^3$ and minimal $\sim 5\cdot 10^{-30}$ g/sm$^3$ ) energy density of matter. The total energy density of all the matter in the Universe is always equal to zero. In Riemannian space, the evolution of the Universe amounts to constant alteration of its stages of "expansion" and "contraction". The period of each stage is estimated at (15-16)X10$^9$ years. "Acceleration" in the last third of an "expansion" stage is positive and increases with time. The temperature regime in such a universe is also investigated. Within the framework of the proposed concept, an explanation of the cosmological red shift is given. Finally, a theoretical explanation is given for the observed effect of the non-Faraday cosmological rotation of the polarization plane of the electromagnetic radiation emitted by distant radio galaxies.