Obs. : 2018-01-17 Planet Ly alpha (photons/cm^2/sec) Mercury 3.409e+11 Venus 3.462e+11 Earth 3.491e+11 Mars 3.420e+11 Jupiter 3.420e+11 Saturn 3.409e+11 Uranus 3.417e+11 Neptune 3.444e+11 Pluto 3.427e+11