Obs. : 2010-09-08 Planet Ly alpha (photons/cm^2/sec) Mercury 3.601e+11 Venus 3.766e+11 Earth 3.725e+11 Mars 3.766e+11 Jupiter 3.643e+11 Saturn 3.748e+11 Uranus 3.643e+11 Neptune 3.725e+11 Pluto 3.779e+11