Obs. : 2012-02-03 Planet Ly alpha (photons/cm^2/sec) Mercury 4.393e+11 Venus 4.413e+11 Earth 4.276e+11 Mars 4.387e+11 Jupiter 4.240e+11 Saturn 4.408e+11 Uranus 4.362e+11 Neptune 4.449e+11 Pluto 4.327e+11