  Being generated, the relic neutrino background contained equal fractions of
electron $\nu_e$, muon $\nu_\mu$, and taon $\nu_\tau$ neutrinos. We show that
the gravitational field of our Galaxy and other nearby cosmic objects changes
this composition near the Solar System, enriching it with the heaviest neutrino
$nu_3$. This mass state is almost free of the electron component (only $\sim
2\%$ of $\nu_e$) and contains more muon component than the tau one. As a
result, the relic background becomes enriched with taon and particularly muon
neutrinos. The electron relic neutrinos are the rarest for a terrestrial
observer: instead of $1/3$, the relic background may contain only $\gtrsim
20\%$ of them.
