Pictured here is a partial lunar eclipse that seems to swirl with different hues on Aug. 16, 2008. Why does a lunar eclipse involve so many color changes? The moon does not generate any light of its own, instead reflecting light off the sun. So when the Earth blocks the sun, it influences the lunar colors. You’ll notice that the moon does not entirely black out during a total lunar eclipse. This is because some refracted light from the sun still reaches the moon, as it is simply being bent around the Earth by our atmosphere.
So why does the moon look red? “Only red light can penetrate through the gas and dust in the Earth’s atmosphere to reach the moon” during an eclipse. When there is less dust in the Earth’s atmosphere, the moon can appear grey or yellow. When there is more dust, it can turn “tobacco” color. A blood red moon happens when the Earth’s atmosphere contains a huge amount of dust mixed in with the Earth’s natural gases. A volcanic eruption may bring on a blood red moon.