Obs. : 2009-06-01 Planet Ly alpha (photons/cm^2/sec) Mercury 3.625e+11 Venus 3.583e+11 Earth 3.528e+11 Mars 3.587e+11 Jupiter 3.464e+11 Saturn 3.828e+11 Uranus 3.478e+11 Neptune 3.464e+11 Pluto 3.528e+11