The rest-mass of neutrino and the cosmic clustering phenomena

During their contracting and clustering, massive neutrinos can carry ordinary matter through their gravitational coupling, contracting to form the object with mass just at the right order of cluster of galaxies. Hence, massive neutrinos may provide the clue to explain naturally the formation of clusters of galaxies. However, as is well known, the clustering of ordinary matter before the era of the recombination could make the microwave background radiation non-isotropic, so the observational fact that this radiation is highly isotropic has usually been regarded as the strong disproof for any clustering before the recombination. In this paper, the authors discuss the contracting process from the starting point of preferential clustering (T/sub 1/≅4x10/sup 4/ K) to the era of the recombination (T/sub 2/≅4x10/sup 3/ K), and prove the nonuniformity reached at T/sub 2/ to be too small to conflict with the observational fact in microwave background radiation