Obs. : 2016-04-20 Planet Ly alpha (photons/cm^2/sec) Mercury 4.067e+11 Venus 4.050e+11 Earth 3.811e+11 Mars 3.840e+11 Jupiter 3.845e+11 Saturn 3.840e+11 Uranus 4.050e+11 Neptune 3.972e+11 Pluto 3.923e+11