Obs. : 2015-10-15 Planet Ly alpha (photons/cm^2/sec) Mercury 3.965e+11 Venus 4.252e+11 Earth 4.318e+11 Mars 4.105e+11 Jupiter 4.105e+11 Saturn 3.788e+11 Uranus 4.096e+11 Neptune 4.025e+11 Pluto 3.885e+11