Obs. : 2012-01-27 Planet Ly alpha (photons/cm^2/sec) Mercury 3.913e+11 Venus 4.269e+11 Earth 4.345e+11 Mars 3.931e+11 Jupiter 4.486e+11 Saturn 3.797e+11 Uranus 4.336e+11 Neptune 4.218e+11 Pluto 3.841e+11