Obs. : 2012-08-31 Planet Ly alpha (photons/cm^2/sec) Mercury 3.827e+11 Venus 4.220e+11 Earth 4.680e+11 Mars 4.191e+11 Jupiter 4.376e+11 Saturn 4.191e+11 Uranus 4.584e+11 Neptune 4.642e+11 Pluto 4.626e+11