Obs. : 2009-05-29 Planet Ly alpha (photons/cm^2/sec) Mercury 3.615e+11 Venus 3.567e+11 Earth 3.471e+11 Mars 3.582e+11 Jupiter 3.456e+11 Saturn 3.659e+11 Uranus 3.516e+11 Neptune 3.456e+11 Pluto 3.471e+11