What causes the green flash at sunset?
There were a series of articles in “Scientific American” magazine on the Green Flash back in the 1960s. People were not sure they were really seeing something real or just experiencing color fatigue in their eyes from looking at the sun set. It was determined by using photography that it was a real event although rare. Most people have never seen it. I’ve never seen it. It is caused by the sun light bending through a very humid layer of air, which increases the index of refraction, and as the sun sets you see a rapid shift through the rainbow colors. It only last for a split second, which is why it is called a flash.
