Obs. : 2009-01-14 Planet Ly alpha (photons/cm^2/sec) Mercury 3.541e+11 Venus 3.528e+11 Earth 3.493e+11 Mars 3.495e+11 Jupiter 3.541e+11 Saturn 3.446e+11 Uranus 3.528e+11 Neptune 3.554e+11 Pluto 3.446e+11