Obs. : 2012-09-09 Planet Ly alpha (photons/cm^2/sec) Mercury 4.520e+11 Venus 4.622e+11 Earth 4.043e+11 Mars 4.078e+11 Jupiter 4.553e+11 Saturn 4.214e+11 Uranus 4.210e+11 Neptune 4.043e+11 Pluto 3.897e+11