Obs. : 2013-03-01 Planet Ly alpha (photons/cm^2/sec) Mercury 4.128e+11 Venus 3.947e+11 Earth 4.086e+11 Mars 4.128e+11 Jupiter 4.230e+11 Saturn 3.878e+11 Uranus 4.208e+11 Neptune 3.947e+11 Pluto 3.826e+11