Key points are not available for this paper at this time.
Modern cosmological theories imply that the universe is filled with a shallow degenerate Fermi sea of neutrinos. In the steady state and oscillating models (and perhaps also the "big bang" theories) it can be shown rigorously that the proportion of filled neutrino levels (plus the proportion of filled antineutrino levels) is precisely one up to a finite Fermi energy E₅. The proof takes into account both absorption and the repressive effects of already filled levels on neutrino emission. Experiment shows that E₅200 eV for antineutrinos and E₅1000 eV for neutrinos. The degenerate neutrinos could be observed (if E₅>10 eV) by looking for apparent violations of energy conservation in ^- decay. In the steady state and evolutionary cosmologies E₅ is much too low to ever be observed, but in the oscillating cosmologies E₅5R₂ MeV, where R₂ is the minimum radius of the universe in units of its present radius; thus experiment already shows that the universe will contract by a factor over 10^3, if at all. Astronomical evidence plus Einstein's field equation (without cosmological constant) require in an oscillating cosmology that E₅<210^-3 eV (so R₂<10^-9) and suggest that higher energy neutrinos may represent the bulk of the energy of the universe. A model universe incorporating this idea is constructed.
Steven Weinberg (Thu,) studied this question.