Obs. : 2013-04-05 Planet Ly alpha (photons/cm^2/sec) Mercury 3.845e+11 Venus 4.032e+11 Earth 4.606e+11 Mars 4.032e+11 Jupiter 4.198e+11 Saturn 4.447e+11 Uranus 3.940e+11 Neptune 3.881e+11 Pluto 4.120e+11