Obs. : 2009-11-10 Planet Ly alpha (photons/cm^2/sec) Mercury 3.827e+11 Venus 3.552e+11 Earth 3.512e+11 Mars 3.514e+11 Jupiter 3.704e+11 Saturn 3.475e+11 Uranus 3.613e+11 Neptune 3.663e+11 Pluto 3.809e+11