Pillar Punctuating a Purple Sky
March 12, 2004
Early last month, I noticed an eye-catching sunset near my home in New Carlisle, Ohio and decided to take a picture of it. When I returned with my camera, a minute or two later, this extraordinary, pink pillar greeted me -- talking about being at the right place and at the right time. Pillars are caused by refraction and reflection of sunlight off of ice crystals (plate shaped hexagonal crystals ) in the cloud layer above the Sun. Light is refracted through the underside of the plate crystal and then reflected off of the upperside before exiting the way it entered, through the underside. The brightest beams result when the crystals are all nearly perfectly aligned and are of similar size.