Obs. : 2011-05-30 Planet Ly alpha (photons/cm^2/sec) Mercury 4.016e+11 Venus 4.006e+11 Earth 4.168e+11 Mars 4.006e+11 Jupiter 4.054e+11 Saturn 4.450e+11 Uranus 4.032e+11 Neptune 4.042e+11 Pluto 4.168e+11