Obs. : 2017-04-18 Planet Ly alpha (photons/cm^2/sec) Mercury 3.521e+11 Venus 3.602e+11 Earth 3.745e+11 Mars 3.501e+11 Jupiter 3.630e+11 Saturn 3.824e+11 Uranus 3.553e+11 Neptune 3.636e+11 Pluto 3.820e+11