Obs. : 2017-04-06 Planet Ly alpha (photons/cm^2/sec) Mercury 4.009e+11 Venus 3.950e+11 Earth 3.686e+11 Mars 3.971e+11 Jupiter 3.672e+11 Saturn 3.769e+11 Uranus 4.020e+11 Neptune 3.894e+11 Pluto 3.765e+11