Obs. : 2017-04-17 Planet Ly alpha (photons/cm^2/sec) Mercury 3.533e+11 Venus 3.629e+11 Earth 3.718e+11 Mars 3.506e+11 Jupiter 3.566e+11 Saturn 3.783e+11 Uranus 3.568e+11 Neptune 3.676e+11 Pluto 3.818e+11