Obs. : 2014-04-17 Planet Ly alpha (photons/cm^2/sec) Mercury 3.941e+11 Venus 3.920e+11 Earth 4.229e+11 Mars 4.181e+11 Jupiter 3.793e+11 Saturn 4.229e+11 Uranus 3.941e+11 Neptune 3.920e+11 Pluto 3.970e+11