  It is shown how high energy neutrino beams from very distant sources can be
utilised to learn about some properties of neutrinos such as lifetimes, mass
hierarchy etc. Furthemore, even mixing elements such as U_e3 and the CPV phase
in the neutrino mixing matrix can be measured in principle. Pseudo-Dirac mass
differences as small as 10^-18 eV^2 can be probed as well.
