Obs. : 2010-07-08 Planet Ly alpha (photons/cm^2/sec) Mercury 3.741e+11 Venus 3.770e+11 Earth 3.763e+11 Mars 3.909e+11 Jupiter 3.752e+11 Saturn 3.909e+11 Uranus 3.733e+11 Neptune 3.722e+11 Pluto 3.822e+11