Obs. : 2013-04-27 Planet Ly alpha (photons/cm^2/sec) Mercury 4.396e+11 Venus 4.524e+11 Earth 4.307e+11 Mars 4.396e+11 Jupiter 4.731e+11 Saturn 4.375e+11 Uranus 4.346e+11 Neptune 4.099e+11 Pluto 4.101e+11