Obs. : 2010-12-17 Planet Ly alpha (photons/cm^2/sec) Mercury 3.755e+11 Venus 3.802e+11 Earth 3.801e+11 Mars 3.755e+11 Jupiter 3.756e+11 Saturn 3.813e+11 Uranus 3.767e+11 Neptune 3.742e+11 Pluto 3.755e+11