Obs. : 2017-04-28 Planet Ly alpha (photons/cm^2/sec) Mercury 3.524e+11 Venus 3.495e+11 Earth 3.484e+11 Mars 3.581e+11 Jupiter 3.573e+11 Saturn 3.448e+11 Uranus 3.524e+11 Neptune 3.475e+11 Pluto 3.429e+11