Obs. : 2014-04-20 Planet Ly alpha (photons/cm^2/sec) Mercury 4.148e+11 Venus 4.141e+11 Earth 4.361e+11 Mars 4.487e+11 Jupiter 4.289e+11 Saturn 4.361e+11 Uranus 4.139e+11 Neptune 4.135e+11 Pluto 4.214e+11