The neutrino mass values extracted from the pioneering Nobel Prize winning measurements of Kajita and co-workers at Superkamiokande were used in the classical Newton-Laplace equation for computing the speed of propagation of acoustic waves in gases comprising neutrinos. It is found that, surprisingly, acoustic waves in the lightest neutrino environments proceed with the speed of light in vacuum, c. This allows for the computation of c in terms of the lightest neutrino mass within 1% and is consistent with the fact that gravitational waves have been recently found to propagate with the speed of light. It is also found that the rest energy, m1c2, of the lightest neutrinos coincides with the photon energy at the cosmic background radiation temperature (CMBR). These findings are discussed in terms of the dual nature of photons and its possible interrelation with the omnipresent neutrinos. The present results also confirm that neutrino gases behave as ideal gases with only one-half of a translational degree of freedom, consistent with their one-dimensional, and practically one-directional, degree of freedom.