Obs. : 2010-04-20 Planet Ly alpha (photons/cm^2/sec) Mercury 3.755e+11 Venus 3.746e+11 Earth 3.690e+11 Mars 3.763e+11 Jupiter 3.596e+11 Saturn 3.741e+11 Uranus 3.596e+11 Neptune 3.554e+11 Pluto 3.554e+11