Thread: Re: The end of inflation View Single Post


In message , ebunn@lfa221051.richmond.edu writes >In article , >Jasper Stein wrote: > >>??? I thought the neutrino background $+has+$ been observed (and is about >>1.7K)? > > >Not that I've heard. I'd be utterly shocked if this were the case. >The neutrinos in the cosmic neutrino background have energies less >than an meV (m for "milli-"). Neutrinos that we can actually detect >are in the MeV range (or at least hundreds of keV). > >There is strong indirect evidence that the cosmic neutrino background >exists, or at least that it existed when the Universe was about a >second old. If it weren't there, then the amounts of various light >elements produced in big-bang nucleosynthesis would be all wrong. But >while that's strong evidence for the CNB, I wouldn't count it as a >"detection." > You gave a figure for energy in neutrinos, which I assume was based on the neutrino having zero mass, but do we have any idea how much missing matter there may be in cold neutrinos if neutrinos have mass? Regards -- Charles Francis