Obs. : 2009-06-02 Planet Ly alpha (photons/cm^2/sec) Mercury 3.647e+11 Venus 3.555e+11 Earth 3.564e+11 Mars 3.614e+11 Jupiter 3.475e+11 Saturn 3.831e+11 Uranus 3.483e+11 Neptune 3.475e+11 Pluto 3.564e+11