Obs. : 2010-01-12 Planet Ly alpha (photons/cm^2/sec) Mercury 3.532e+11 Venus 3.604e+11 Earth 3.762e+11 Mars 3.743e+11 Jupiter 3.618e+11 Saturn 3.574e+11 Uranus 3.628e+11 Neptune 3.618e+11 Pluto 3.532e+11