Obs. : 2013-09-28 Planet Ly alpha (photons/cm^2/sec) Mercury 3.950e+11 Venus 3.964e+11 Earth 3.897e+11 Mars 3.976e+11 Jupiter 4.015e+11 Saturn 3.964e+11 Uranus 3.897e+11 Neptune 3.706e+11 Pluto 3.780e+11