2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/13898"Power Law Cosmologies" are defined by their growth of the cosmological scale factor as $ t^α$ regardless of the matter content or cosmological epoch. Constraints from the current age of the Universe and from the high redshift supernovae data require ``large'' $α$ ($\approx 1$). We reinforce this by latest available observations. Such a large $α$ is also consistent with the right amount of helium and the lowest observed metallicity in the universe for a model with the baryon entropy ratio $\approx 8.1\times 10^{-9}$.Plain Tex File, 4 postscript figuresAstrophysicstext