# A NEW MODEL OF THE BIG BANG AND THE UNIVERSE EXPANSION. A COMPARISON WITH MODERN OBSERVATIONAL DATA AND COSMOLOGICAL THEORIES

A. Einstein, trying to describe the stationary Universe within the general theory of relativity (GRT), has introduced in GRT a constant \(\Lambda\), called "a cosmological constant". Regardless to the Universe A. Friedman has constructed in 1922 the non-stationary solution within GRT with \(\Lambda = 0\). Scalar parameters of the medium and certain "a scale factor" in this solution are functions only of time, and speed **u** in co-moving coordinates is zero. In 1929 E. Hubble, measuring Doppler shift of light of the remote galaxies, has formulated the law according to which far galaxies move away from us with speed of **u** proportional to radius vector **r** to them: **u** = *H*(*t*)**r**. Time-dependent *t* function *H*(*t*) is called "Hubble's constant". If galaxies scatter, then if we have the suitable solution, it is possible to define, when they were together, i.e. when they (more exactly, gas particles from which galaxies were created then) "have scattered from a point or almost from a point". Friedman solution has been taken as suitable after Hubble discovery. In it the singularity moment, when the density is infinite everywhere, is taken for the always boundless Universe expansion beginning, and the scale factor is equal to zero. Time *t*_{0}, which is read from this moment, is the Universe "life" time. Possibility of Universe expansion description with A. Friedman's solution did not cause doubts till 1998, when two groups of American astronomers have discovwered its discrepancy to observational data. For elimination of the discovered discrepancy A. Friedman's solution has been generalized on nonzero \(\Lambda\), which choice has allowed to conform observations with this solution. Like A. Einstein approach, the computed values of \(\Lambda\) lead to effect of antigravitation. Three representatives of the mentioned groups have received Nobel Prize in 2011 for such antigravitation discovery and accompanying it accelerated Universe expansion. Unknown for the present carrier of anti-gravitation, connected with \(\Lambda\), is called "dark energy".

In 2015 authors of the report have solved in classical and in relativistic statements a problem on dispersion in a void of the gas compressed in a point or in its small vicinity (further - "a problem on dispersion") [1]. Comparisons of the simple solution obtained (in both statements speed of u = r/t, i.e. H (t) = 1/t) with the same observational data surprisingly have shown, that it without attraction of any empirical constants describes the data not worse than any modern cosmological theory (\(\Lambda CDM\)) with dark energy (\(\Lambda\)) and matter (CDM - Cold Dark Matter). In the solution obtained (at *\(t = +0\)* and \(0 \leq r/(ct) \leq 1\), *c* is the speed of light) the pressure *p*, the specific (units of volume) enthalpy *w* and the internal energy e = *w – p* instantly vanish, i.e. e instantly transforms to the kinetic energy of the gas. Validity of the told confirms figure with more than two hundreds NASA variants of four most reliable observational data sets processing with tens modern cosmological theories [2] which form area, covered with grey crosses (vertical and horizontal parts of crosses give errors of Hubble constant *H* definition and the Universe lifetime *t*_{0}). A curve *1*, defined by a formula *H* = 978/*t*_{0} which is the sequence of the solution **u** = **r**/*t*, passes through the area, here *H* in km / (s×Mpc), *t*_{0} in Gyrs.

Grey crosses are the reliable observational data processed with modern

cosmological theories (\(\Lambda CDM\)) [2]; curve 1 corresponds to the formula *H* = 978/*t*_{0},

curve 2 – to the formula *H* = 652/*t*_{0},which is a consequence of Friedman solution with \(\Lambda = 0\)

The formula **u** = **r**/*t* at the description of the extending Universe is used throughout almost all E. Milne's monograph [3]. Milne has obtained it, however, not from the solution of a problem on dispersion of the gas compressed in a point, but on the basis of cosmological principle formulated by him and additional, sometimes not enough reasonable assumptions. Milne finishes with a formula **u** = (2/3)**r**/*t*, which is a consequence of Friedman solution with \(\Lambda = 0\) for Universe expansion from thermodynamically nonrelativistic gas. For the reasons specified, after Milne the formula **u** = **r**/*t*, entered by him, was not involved in the description of the Universe expansion. In the figure the curve *2* corresponds to the solution **u** = (2/3)**r**/*t*, which is lying much lower than covered with crosses area.

Due to the dark energy which has appeared with introduction \(\Lambda \neq 0\), we read [4]: "The discovery of dark energy dotted the i's and crossed the t's in observational cosmology. The standard cosmological model (\(\Lambda CDM\)) fitting the whole set of observational data arose for the first time in the development of science. Nowadays, it has no serious rivals". Comparison of the covered with crosses area in the figure with the curve 1 testifies to appearance of such competitor without any uniform empirical constant, without dark energy and a matter. If the dark matter can be necessary for the description of Universe expansion slowdown, in the light of the solution constructed above, there is no need of dark energy.

REFERENCES

- Valyiev Kh.F., Kraiko A.N. The dispersion of an ideal gas from a point into a void. A new model of the Big Bang and the expansion of the Universe // Prikl. Mat. Mech. 2015. V. 79. No. 6. P. 793-807.
- WMAP Cosmological parameters Model/Data Set Matrix. NASA; http://lambda.gsfc.nasa.gov/product/map/current/ parameters.cfm.
- Milne E.A. Relativity, Gravitation and World-structure // Oxford: Clarendon Press, 1935. 365 p.
- Lukash V.N., Rubakov V.A. Dark energy: myths and reality // Physics – Uspekhi. 2008. V. 51. No. 3. P. 283-289.