Obs. : 2014-05-20 Planet Ly alpha (photons/cm^2/sec) Mercury 4.066e+11 Venus 3.845e+11 Earth 3.934e+11 Mars 4.096e+11 Jupiter 4.240e+11 Saturn 3.987e+11 Uranus 3.764e+11 Neptune 3.786e+11 Pluto 3.937e+11