Obs. : 2011-05-15 Planet Ly alpha (photons/cm^2/sec) Mercury 4.072e+11 Venus 4.072e+11 Earth 3.897e+11 Mars 4.072e+11 Jupiter 4.072e+11 Saturn 3.936e+11 Uranus 4.118e+11 Neptune 4.048e+11 Pluto 3.920e+11