Obs. : 2012-07-28 Planet Ly alpha (photons/cm^2/sec) Mercury 3.812e+11 Venus 3.710e+11 Earth 4.294e+11 Mars 4.348e+11 Jupiter 3.710e+11 Saturn 4.406e+11 Uranus 3.817e+11 Neptune 4.129e+11 Pluto 4.294e+11