Obs. : 2014-04-18 Planet Ly alpha (photons/cm^2/sec) Mercury 4.190e+11 Venus 4.189e+11 Earth 4.477e+11 Mars 4.511e+11 Jupiter 4.131e+11 Saturn 4.477e+11 Uranus 4.187e+11 Neptune 4.185e+11 Pluto 4.276e+11