Obs. : 2015-02-20 Planet Ly alpha (photons/cm^2/sec) Mercury 5.108e+11 Venus 4.856e+11 Earth 4.674e+11 Mars 4.856e+11 Jupiter 4.674e+11 Saturn 4.689e+11 Uranus 4.811e+11 Neptune 4.920e+11 Pluto 4.945e+11