Obs. : 2018-05-21 Planet Ly alpha (photons/cm^2/sec) Mercury 3.257e+11 Venus 3.215e+11 Earth 3.195e+11 Mars 3.187e+11 Jupiter 3.195e+11 Saturn 3.197e+11 Uranus 3.247e+11 Neptune 3.201e+11 Pluto 3.176e+11