Obs. : 2010-01-20 Planet Ly alpha (photons/cm^2/sec) Mercury 3.605e+11 Venus 3.652e+11 Earth 3.581e+11 Mars 3.581e+11 Jupiter 3.631e+11 Saturn 3.576e+11 Uranus 3.598e+11 Neptune 3.631e+11 Pluto 3.605e+11