Helium Production in the Different Cosmological Models

Abstract

The aim of the present report is to emphasize the role of the helium problem as the key one for different aspects of cosmological speculations. This is not surprising, because the processes which produce the helium and other elements in primordial matter take place during the first stages of the cosmological expansion of the Universe.The theory gives three critical values of the He4 abundance in pre-stellar matter, depending on assumptions about the behaviour of the Universe near the singularity. The three critical values are:(1) practically no He4 at all;(2) about 25% of He4 by mass;(3) practically entirely He4.Although intermediate values of He4 are in principle possible, the cosmological models permitting such values are highly improbable. It is obvious that the helium abundance is less than 100%, and that even rough estimates of whether the stellar matter consists almost entirely of hydrogen, or if it has a significant part of He4, are of tremendous importance. The much-more-difficult determination of traces of primeval He3, D, Li6, would be of great help in making definite cosmological conclusions.