Obs. : 2009-12-05 Planet Ly alpha (photons/cm^2/sec) Mercury 3.696e+11 Venus 3.583e+11 Earth 3.448e+11 Mars 3.414e+11 Jupiter 3.629e+11 Saturn 3.404e+11 Uranus 3.552e+11 Neptune 3.629e+11 Pluto 3.696e+11