Obs. : 2010-07-15 Planet Ly alpha (photons/cm^2/sec) Mercury 3.868e+11 Venus 3.841e+11 Earth 3.904e+11 Mars 3.894e+11 Jupiter 3.843e+11 Saturn 3.926e+11 Uranus 3.843e+11 Neptune 3.875e+11 Pluto 3.929e+11