Obs. : 2012-08-27 Planet Ly alpha (photons/cm^2/sec) Mercury 3.916e+11 Venus 3.989e+11 Earth 4.442e+11 Mars 4.370e+11 Jupiter 4.124e+11 Saturn 4.370e+11 Uranus 4.312e+11 Neptune 4.431e+11 Pluto 4.463e+11