Obs. : 2026-07-02 Planet Ly alpha (photons/cm^2/sec) Mercury 8.506e+08 Venus 8.818e+08 Earth 8.095e+08 Mars 7.921e+08 Jupiter 8.712e+08 Saturn 7.723e+08 Uranus 7.921e+08 Neptune 7.748e+08 Pluto 8.095e+08