Obs. : 2009-11-21 Planet Ly alpha (photons/cm^2/sec) Mercury 3.554e+11 Venus 3.499e+11 Earth 3.676e+11 Mars 3.654e+11 Jupiter 3.555e+11 Saturn 3.496e+11 Uranus 3.577e+11 Neptune 3.555e+11 Pluto 3.566e+11