Obs. : 2017-04-27 Planet Ly alpha (photons/cm^2/sec) Mercury 3.826e+11 Venus 3.798e+11 Earth 3.825e+11 Mars 3.827e+11 Jupiter 3.912e+11 Saturn 3.772e+11 Uranus 3.826e+11 Neptune 3.773e+11 Pluto 3.755e+11