Obs. : 2012-08-14 Planet Ly alpha (photons/cm^2/sec) Mercury 4.556e+11 Venus 4.491e+11 Earth 3.862e+11 Mars 4.062e+11 Jupiter 4.468e+11 Saturn 4.062e+11 Uranus 4.058e+11 Neptune 3.910e+11 Pluto 3.847e+11