Obs. : 2010-01-21 Planet Ly alpha (photons/cm^2/sec) Mercury 3.654e+11 Venus 3.670e+11 Earth 3.597e+11 Mars 3.597e+11 Jupiter 3.647e+11 Saturn 3.581e+11 Uranus 3.592e+11 Neptune 3.647e+11 Pluto 3.654e+11