Obs. : 2013-05-04 Planet Ly alpha (photons/cm^2/sec) Mercury 4.228e+11 Venus 4.226e+11 Earth 4.638e+11 Mars 4.228e+11 Jupiter 4.224e+11 Saturn 4.723e+11 Uranus 4.312e+11 Neptune 4.363e+11 Pluto 4.551e+11