Obs. : 2013-11-18 Planet Ly alpha (photons/cm^2/sec) Mercury 4.160e+11 Venus 4.242e+11 Earth 4.354e+11 Mars 4.100e+11 Jupiter 4.245e+11 Saturn 4.187e+11 Uranus 4.473e+11 Neptune 4.420e+11 Pluto 4.218e+11