Obs. : 2015-01-17 Planet Ly alpha (photons/cm^2/sec) Mercury 3.956e+11 Venus 3.956e+11 Earth 3.937e+11 Mars 3.898e+11 Jupiter 4.172e+11 Saturn 4.219e+11 Uranus 3.812e+11 Neptune 3.898e+11 Pluto 4.074e+11