Obs. : 2017-12-11 Planet Ly alpha (photons/cm^2/sec) Mercury 3.652e+11 Venus 3.517e+11 Earth 3.550e+11 Mars 3.313e+11 Jupiter 3.339e+11 Saturn 3.652e+11 Uranus 3.608e+11 Neptune 3.737e+11 Pluto 3.744e+11