Obs. : 2011-08-16 Planet Ly alpha (photons/cm^2/sec) Mercury 3.904e+11 Venus 3.939e+11 Earth 4.006e+11 Mars 3.873e+11 Jupiter 3.874e+11 Saturn 4.028e+11 Uranus 3.887e+11 Neptune 3.937e+11 Pluto 4.011e+11