Obs. : 2017-01-10 Planet Ly alpha (photons/cm^2/sec) Mercury 2.657e+11 Venus 2.787e+11 Earth 2.655e+11 Mars 2.787e+11 Jupiter 2.600e+11 Saturn 2.657e+11 Uranus 2.712e+11 Neptune 2.787e+11 Pluto 2.718e+11