Obs. : 2013-09-15 Planet Ly alpha (photons/cm^2/sec) Mercury 3.923e+11 Venus 4.003e+11 Earth 3.802e+11 Mars 3.654e+11 Jupiter 3.743e+11 Saturn 4.003e+11 Uranus 3.771e+11 Neptune 3.756e+11 Pluto 3.832e+11