Obs. : 2013-02-27 Planet Ly alpha (photons/cm^2/sec) Mercury 4.310e+11 Venus 4.120e+11 Earth 4.013e+11 Mars 4.310e+11 Jupiter 4.253e+11 Saturn 3.943e+11 Uranus 4.341e+11 Neptune 4.120e+11 Pluto 3.965e+11