KnowraCosmic neutrino backgroundLinked fromLinked fromThe 5 pages that link to Cosmic neutrino background, each with the reason it gives.All 5Related 4Compared with 1Cosmic microwave backgroundCompared with: It is a parallel cosmic relic, but neutrinos are far harder to detect directly.Neutrino massRelated: Massive relic neutrinos influence cosmic expansion and the growth of structure.Planck satelliteRelated: Planck’s data constrained the effective number of relativistic species, including any contribution from relic neutrinos.Observational cosmologyRelated: Detecting its effects would test early-universe physics beyond the microwave background.Photon epochRelated: Relativistic neutrinos contributed substantially to radiation density alongside photons.