Obs. : 2012-08-11 Planet Ly alpha (photons/cm^2/sec) Mercury 4.568e+11 Venus 4.607e+11 Earth 4.177e+11 Mars 3.933e+11 Jupiter 4.601e+11 Saturn 3.933e+11 Uranus 4.490e+11 Neptune 4.278e+11 Pluto 4.104e+11