Obs. : 2011-02-22 Planet Ly alpha (photons/cm^2/sec) Mercury 3.970e+11 Venus 3.928e+11 Earth 3.678e+11 Mars 3.970e+11 Jupiter 3.949e+11 Saturn 3.728e+11 Uranus 3.989e+11 Neptune 3.970e+11 Pluto 3.906e+11