Obs. : 2009-05-25 Planet Ly alpha (photons/cm^2/sec) Mercury 3.604e+11 Venus 3.567e+11 Earth 3.482e+11 Mars 3.581e+11 Jupiter 3.471e+11 Saturn 3.563e+11 Uranus 3.515e+11 Neptune 3.471e+11 Pluto 3.482e+11