Obs. : 2010-12-15 Planet Ly alpha (photons/cm^2/sec) Mercury 3.715e+11 Venus 3.768e+11 Earth 3.796e+11 Mars 3.715e+11 Jupiter 3.770e+11 Saturn 3.810e+11 Uranus 3.770e+11 Neptune 3.757e+11 Pluto 3.715e+11