neutrinos cannot interact with anything easily as that of other elementary particles. The interaction cross section (area normal to the neutrino flux) is found by experiment to have very small value.
http://prola.aps.org/abstract/PRD/v59/i11/e113005
and the detected number for solar neutrinos is only 1/3 of the predicted value. Scientists theorize this as due to neutrino oscillations between the three types: electron, muon, and tau neutrinos.