Obs. : 2026-06-18 Planet Ly alpha (photons/cm^2/sec) Mercury 7.561e+08 Venus 7.546e+08 Earth 7.811e+08 Mars 7.696e+08 Jupiter 7.561e+08 Saturn 7.922e+08 Uranus 7.668e+08 Neptune 8.075e+08 Pluto 7.949e+08