Obs. : 2010-09-18 Planet Ly alpha (photons/cm^2/sec) Mercury 3.701e+11 Venus 3.874e+11 Earth 3.892e+11 Mars 3.874e+11 Jupiter 3.869e+11 Saturn 3.793e+11 Uranus 3.869e+11 Neptune 3.892e+11 Pluto 3.939e+11