Obs. : 2008-05-05 Planet Ly alpha (photons/cm^2/sec) Mercury 3.572e+11 Venus 3.594e+11 Earth 3.441e+11 Mars 3.489e+11 Jupiter 3.386e+11 Saturn 3.481e+11 Uranus 3.492e+11 Neptune 3.409e+11 Pluto 3.404e+11