Obs. : 2016-01-17 Planet Ly alpha (photons/cm^2/sec) Mercury 4.009e+11 Venus 4.039e+11 Earth 3.926e+11 Mars 3.985e+11 Jupiter 3.965e+11 Saturn 4.019e+11 Uranus 3.871e+11 Neptune 3.902e+11 Pluto 4.009e+11