Obs. : 2012-06-17 Planet Ly alpha (photons/cm^2/sec) Mercury 4.213e+11 Venus 4.421e+11 Earth 4.262e+11 Mars 4.028e+11 Jupiter 4.421e+11 Saturn 4.026e+11 Uranus 4.551e+11 Neptune 4.440e+11 Pluto 4.262e+11