Obs. : 2009-11-27 Planet Ly alpha (photons/cm^2/sec) Mercury 3.602e+11 Venus 3.574e+11 Earth 3.528e+11 Mars 3.543e+11 Jupiter 3.539e+11 Saturn 3.549e+11 Uranus 3.479e+11 Neptune 3.521e+11 Pluto 3.593e+11