Obs. : 2009-12-26 Planet Ly alpha (photons/cm^2/sec) Mercury 3.678e+11 Venus 3.665e+11 Earth 3.560e+11 Mars 3.565e+11 Jupiter 3.582e+11 Saturn 3.617e+11 Uranus 3.530e+11 Neptune 3.582e+11 Pluto 3.665e+11