  An electron motion in a dense neutrino flux is investigated. The Dirac
equation exact solutions for the electron energy and wave function in this
external environment are obtained. On this basis we predict the existence of an
electromagnetic radiation that can be emitted by electrons in dense neutrino
fluxes. We term this phenomenon "the spin light of electron in dense neutrino
flux" ($SLe_{\nu}$). The main properties of the $SLe_{\nu}$ are studied. We
argue that the $SLe_{\nu}$ in dense neutrino fluxes should have important
consequences in astrophysics and for supernovae processes in particular.
