Obs. : 2011-02-09 Planet Ly alpha (photons/cm^2/sec) Mercury 3.721e+11 Venus 3.755e+11 Earth 3.848e+11 Mars 3.721e+11 Jupiter 3.771e+11 Saturn 3.897e+11 Uranus 3.771e+11 Neptune 3.723e+11 Pluto 3.784e+11