Optical Emission Lines from Warm Interstellar Clouds: A Decisive Test of the Decaying Neutrino Theory

Recently developed instruments such as the Taurus Tunable Filter and the Wisconsin Hα Mapper should be able to detect some or all of the optical emission lines Hα, [O I] λ6300, [S II] λ6717, [N I] λ5200, and [N II] λ6584 from warm interstellar clouds, such as those observed by Spitzer & Fitzpatrick along the line of sight to the halo star HD 93521. The strengths of these lines should resolve the debate as to whether the free electrons, which Spitzer & Fitzpatrick held responsible for the observed excitation of C II in the clouds, are located mainly in the skins of the clouds or in their interiors. If the free electrons are indeed mainly located in the cloud interiors, then the substantial electron density derived by Spitzer & Fitzpatrick and its constancy from cloud to cloud for the slow-moving clouds, when combined with their opacity to Lyman continuum radiation, lend strong support to the decaying neutrino theory for the ionization of the interstellar medium (Sciama). If the [O I] and [N I] lines are relatively strong but the [N II] line is weak, then this would lend further, decisive, support to this theory, since decay photons are unable to ionize N, although its ionization potential is only 0.9 eV greater than that of H.