Obs. : 2026-09-22 Planet Ly alpha (photons/cm^2/sec) Mercury 7.694e+08 Venus 7.557e+08 Earth 7.810e+08 Mars 8.175e+08 Jupiter 8.139e+08 Saturn 8.012e+08 Uranus 8.153e+08 Neptune 8.012e+08 Pluto 7.607e+08