Obs. : 2008-08-22 Planet Ly alpha (photons/cm^2/sec) Mercury 3.290e+11 Venus 3.290e+11 Earth 3.463e+11 Mars 3.365e+11 Jupiter 3.462e+11 Saturn 3.251e+11 Uranus 3.422e+11 Neptune 3.463e+11 Pluto 3.445e+11