Obs. : 2016-04-17 Planet Ly alpha (photons/cm^2/sec) Mercury 4.203e+11 Venus 4.196e+11 Earth 4.007e+11 Mars 3.991e+11 Jupiter 4.159e+11 Saturn 3.989e+11 Uranus 4.196e+11 Neptune 4.124e+11 Pluto 4.016e+11