Obs. : 2017-03-21 Planet Ly alpha (photons/cm^2/sec) Mercury 3.600e+11 Venus 3.600e+11 Earth 3.649e+11 Mars 3.573e+11 Jupiter 3.649e+11 Saturn 3.648e+11 Uranus 3.581e+11 Neptune 3.621e+11 Pluto 3.630e+11