Obs. : 2010-02-07 Planet Ly alpha (photons/cm^2/sec) Mercury 3.717e+11 Venus 3.814e+11 Earth 3.806e+11 Mars 3.806e+11 Jupiter 3.844e+11 Saturn 3.816e+11 Uranus 3.876e+11 Neptune 3.814e+11 Pluto 3.561e+11