摘要: Production spectra of high-energy neutrinos from galactic cosmic-ray interactions with interstellar gas and extragalactic ultrahigh-energy microwave blackbody photons are presented discussed. These production processes involve the decay charged pions thus related to cosmic ..gamma..-rays neutral pions. Estimates neutrino fluxes various diffuse sources then made, reasons for significant differences previous estimates Small predicted event rates a DUMAND type detection system, combined possible flux prompt atmosphere above 50 TeV, may make study extraterrestrial more difficult than previously thought.