Obs. : 2012-10-26 Planet Ly alpha (photons/cm^2/sec) Mercury 3.887e+11 Venus 4.232e+11 Earth 4.435e+11 Mars 3.825e+11 Jupiter 4.519e+11 Saturn 4.114e+11 Uranus 4.059e+11 Neptune 3.807e+11 Pluto 3.789e+11