The Moon appears to be reddish because of Rayleigh scattering (the same effect that causes sunsets to appear reddish) and the refraction of that light by the Earth's atmosphere into its umbra.[2] The following simulation shows the approximate appearance of the Moon passing through the earth's shadow. The Moon's brightness is exaggerated within the umbral shadow. The southern portion of the Moon was closest to the center of the shadow, making it darkest, and most red in appearance.