Inhomogeneous nucleosynthesis and the cosmic-microwave-background isotropy

It has been known for some time that the standard big-bang nucleosynthesis (described by Yang et al.) puts strong limits on the amount of baryonic matter in the Universe. The recently proposed inhomogeneous nucleosynthesis could potentially invalidate that bound. In view of this possibility, we review the predictions of the cosmic-microwave-background anisotropy, which is expected to be overproduced in most pure baryonic universes when one tries to explain the formation of galaxies. We show that these predictions are not likely to be modified by hiding the baryons in ''lumps'' left over from the QCD phase transition