GALACTIC PERIODICITY AND THE OSCILLATING G-MODEL

We consider the model involving the oscillation of the effective gravi tational constant that has been put forward in an attempt to reconcile the observed periodicity in the galaxy number distribution with the s tandard cosmological models. This model involves a highly nonlinear dy namics which we analyze numerically. We carry out a detailed study of the bound that nucleosynthesis imposes on this model. The analysis sho ws that for any assumed value for Ohm (the total energy density) one c an fix the value of Ohm(bar) (the baryonic energy density) in such a w ay as to accommodate the observational constraints coming from the He- 4 primordial abundance. In particular, if we impose the inflationary v alue Ohm=1 the resulting baryonic energy density turns out to be Ohm(b ar)similar to 0.021. This result lies in the very narrow range 0.016 l ess than or equal to Ohm(bar)less than or equal to 0.026 allowed by th e observed values of the primordial abundances of the other light elem ents. The remaining fraction of Ohm corresponds to dark matter represe nted by a scalar field.