Obs. : 2013-07-31 Planet Ly alpha (photons/cm^2/sec) Mercury 4.167e+11 Venus 4.119e+11 Earth 4.044e+11 Mars 4.167e+11 Jupiter 4.159e+11 Saturn 4.177e+11 Uranus 3.934e+11 Neptune 3.922e+11 Pluto 4.076e+11