  Cosmology yields the most restrictive limits on neutrino masses and
conversely, massive neutrinos would contribute to the cosmic dark-matter
density and would play an important role for the formation of structure in the
universe. Neutrino oscillations may well solve the solar neutrino problem and
can have a significant impact on supernova physics. The neutrino signal from a
future galactic supernova could provide evidence for cosmologically interesting
neutrino masses or set interesting limits.
