Obs. : 2017-12-15 Planet Ly alpha (photons/cm^2/sec) Mercury 3.786e+11 Venus 3.786e+11 Earth 3.889e+11 Mars 3.656e+11 Jupiter 3.671e+11 Saturn 3.839e+11 Uranus 3.908e+11 Neptune 3.951e+11 Pluto 3.895e+11