Obs. : 2011-03-19 Planet Ly alpha (photons/cm^2/sec) Mercury 4.444e+11 Venus 4.261e+11 Earth 3.749e+11 Mars 4.567e+11 Jupiter 4.553e+11 Saturn 3.728e+11 Uranus 4.553e+11 Neptune 4.435e+11 Pluto 3.866e+11