Obs. : 2010-08-17 Planet Ly alpha (photons/cm^2/sec) Mercury 3.722e+11 Venus 3.779e+11 Earth 3.734e+11 Mars 3.779e+11 Jupiter 3.757e+11 Saturn 3.730e+11 Uranus 3.757e+11 Neptune 3.724e+11 Pluto 3.766e+11