Wonders As Full Moon Turns Bloody

A "blood moon" was seen rising in the evening sky across eastern Japan on April 15. The eerie copper red hue was due to a partial lunar eclipse, in which the Earth casts some of its shadow upon the moon. "Blood moons" occur because red light travels further and scatters less than other colors.

When the sun shines from behind the Earth and the moon during an eclipse, the sunlight is refracted by the Earth's atmosphere, dimly illuminating the shadow cast onto the moon.

Since blue light is easily scattered by particles in the atmosphere such as dust, the red light becomes the most prominent source of color for the refracted sunlight.

Though the partial eclipse seen in Japan lasted for only 20 minutes or so after the moonrise, the moon appeared at an altitude low enough for red light to travel easily.