Obs. : 2011-10-15 Planet Ly alpha (photons/cm^2/sec) Mercury 4.372e+11 Venus 4.446e+11 Earth 4.476e+11 Mars 4.527e+11 Jupiter 4.501e+11 Saturn 4.368e+11 Uranus 4.480e+11 Neptune 4.469e+11 Pluto 4.481e+11