Obs. : 2014-04-21 Planet Ly alpha (photons/cm^2/sec) Mercury 4.167e+11 Venus 4.164e+11 Earth 4.314e+11 Mars 4.468e+11 Jupiter 4.406e+11 Saturn 4.314e+11 Uranus 4.158e+11 Neptune 4.159e+11 Pluto 4.230e+11