Obs. : 2009-10-06 Planet Ly alpha (photons/cm^2/sec) Mercury 3.450e+11 Venus 3.450e+11 Earth 3.459e+11 Mars 3.463e+11 Jupiter 3.480e+11 Saturn 3.450e+11 Uranus 3.459e+11 Neptune 3.480e+11 Pluto 3.612e+11