Obs. : 2010-02-13 Planet Ly alpha (photons/cm^2/sec) Mercury 3.677e+11 Venus 3.667e+11 Earth 3.797e+11 Mars 3.795e+11 Jupiter 3.667e+11 Saturn 3.801e+11 Uranus 3.683e+11 Neptune 3.667e+11 Pluto 3.674e+11