Nearly Forgotten Results in Development of Physical Cosmology

NICA is a tool to investigate the early Universe in laboratory. It would be reasonable to recall some essential issues in physical cosmology development. GR was created by A. Einstein in 1915. In 1917 Einstein proposed the first (static) cosmological model. Later A. Eddington proved that the model is unstable therefore it can not be realizable in nature. In 1922 and 1924 A.A. Friedmann found non-stationary solutions for cosmological equations written in the framework of GR. In 1927 G. Lemaître obtained very similar results and, in addition, he derived the Hubble law (E. Hubble obtained this law from observations). Unfortunately, G. Lemaître published his paper in not very popular Belgium journal. In 1931 Lemaître proposed the first version of hot Universe model (he called it hypothesis of the primeval atom). In his book “The Primeval Atom—An Essay on Cosmogony” Lemaître predicted even a background radiation as a signature of his model. At the end of 1940s G. Gamow and his students proposed their hot universe model where he explained primordial nucleosythesis of helium at the initial stage of the Universe evolution. One of the features of Lemaître–Gamow model was an existence of CMB radiation with a temperature around a few K. It was recalled that the discovery of CMB radiation was done by T. Shmaonov in 1956 and his paper was published in 1957 (several years before the discovery done by Penzias and Wilson). In 1965, 1970 E.B. Gliner proposed vacuum like equation of matter which could correspond to exponential explosion of the Universe which was later called inflation. For decades in USSR, A.A. Friedmann’s cosmologocal non-stationary models were treated as purely mathematical results without cosmological and astronomical applications. On September 16, 1925 Friedmann passed away untimely and it would be reasonable to remind today his great contribution in physical cosmology since the authors book on Friedmann wrote “Similarly to Copernicus who forced the Earth to move, Friedmann forced the Universe to expand.”