Obs. : 2010-03-20 Planet Ly alpha (photons/cm^2/sec) Mercury 3.778e+11 Venus 3.753e+11 Earth 3.780e+11 Mars 3.770e+11 Jupiter 3.808e+11 Saturn 3.731e+11 Uranus 3.826e+11 Neptune 3.809e+11 Pluto 3.720e+11