Obs. : 2015-09-18 Planet Ly alpha (photons/cm^2/sec) Mercury 4.239e+11 Venus 4.259e+11 Earth 4.252e+11 Mars 4.250e+11 Jupiter 4.250e+11 Saturn 4.194e+11 Uranus 4.231e+11 Neptune 4.267e+11 Pluto 4.245e+11