Obs. : 2013-07-12 Planet Ly alpha (photons/cm^2/sec) Mercury 4.172e+11 Venus 4.210e+11 Earth 4.343e+11 Mars 4.255e+11 Jupiter 4.255e+11 Saturn 4.500e+11 Uranus 4.370e+11 Neptune 4.332e+11 Pluto 4.343e+11