Figure 3: Neutrinos as Dark Matter Candidate: Contributions of different types to the cosmological matter density &aOmega; in units of the critical density (corrseponding to a flat universe). On the right side, shinig stars in galaxies and galaxy clusters, baryons from Big Bang Nucleosynthesis, unknown cold dark matter as well as the contribution from dark energy (Einstein´s cosmological constant Λ) are shown with as bands of relative contributions. On the left, a yet large range of hot dark matter from massive neutrinos could contribute as Ων to the universe´s mass distribution.