Obs. : 2013-09-06 Planet Ly alpha (photons/cm^2/sec) Mercury 3.559e+11 Venus 3.735e+11 Earth 3.648e+11 Mars 3.666e+11 Jupiter 3.709e+11 Saturn 3.867e+11 Uranus 3.555e+11 Neptune 3.602e+11 Pluto 3.857e+11