Obs. : 2018-01-03 Planet Ly alpha (photons/cm^2/sec) Mercury 3.698e+11 Venus 3.763e+11 Earth 3.660e+11 Mars 3.604e+11 Jupiter 3.604e+11 Saturn 3.763e+11 Uranus 3.676e+11 Neptune 3.780e+11 Pluto 3.820e+11