The would be an interesting neutrino surmizing. Neutrinos cannot be directly detected so it is speculation and observation of effects. And since neutrinos carry no charge, the only detection or observation must rely upon the neutrino to carry some minimum level of energy, which kinda goes against the definition of neutrino... Kind of like catching a breeze with a salmon net.
Solar neutrino flux, which most of it is here on earth, is readily calculated from the observable reactions taking place in the sun. Mostly the proton-proton reaction, each of which yields one electron neutrino.