Obs. : 2013-01-19 Planet Ly alpha (photons/cm^2/sec) Mercury 4.495e+11 Venus 4.501e+11 Earth 4.137e+11 Mars 4.444e+11 Jupiter 4.219e+11 Saturn 4.395e+11 Uranus 4.354e+11 Neptune 4.418e+11 Pluto 4.501e+11