Obs. : 2010-02-19 Planet Ly alpha (photons/cm^2/sec) Mercury 3.889e+11 Venus 3.829e+11 Earth 3.750e+11 Mars 3.750e+11 Jupiter 3.829e+11 Saturn 3.737e+11 Uranus 3.767e+11 Neptune 3.901e+11 Pluto 3.848e+11