Obs. : 2009-10-03 Planet Ly alpha (photons/cm^2/sec) Mercury 3.366e+11 Venus 3.366e+11 Earth 3.499e+11 Mars 3.410e+11 Jupiter 3.488e+11 Saturn 3.350e+11 Uranus 3.499e+11 Neptune 3.488e+11 Pluto 3.548e+11