February 18, 2009--Light pillars scrape the night sky over Victor, Idaho, on January 26. Typically seen in polar regions, the vertical columns of light have been appearing along with frigid temperatures at lower latitudes this winter.
February 18, 2009--A light pillar rises over the setting sun at Lake Tahoe, California, in February 2000.
Though light pillars are often caused by artificial light, sun pillars, as in the above picture, occur when sunlight reflects off the facets of millions of flat ice crystals in very cold air.
The vertical light streaks, which often lengthen and brighten after sunset, can take on the reds, yellows, and purples of the sun and clouds surrounding them, according to the Web site Atmospheric Optics.
Unlike similar-looking lens flares--optical effects caused by camera lenses--light pillars can be seen with the naked eye.
February 18, 2009--Oddly extraterrestrial-looking, "broken" light pillars glow over Ath, Belgium, on November 20, 2006.
Here the ice crystals have clumped into layers in an ice fog rather than spreading out evenly--according to physicist Les Cowley on his Web site Atmospheric Optics. As a result, light shining up from artificial sources, such as streetlights, is turned into dotted lines in the sky.
February 18, 2009--Remarkably tall artificial light pillars are seen in Ontario, Canada, in January 2004 in this composite panoramic photo.
When the photographs were taken, the temperature hovered around -11 degrees Fahrenheit (-24 degrees Celsius), and the air was very still, with a gentle drizzle of ice crystals falling from the sky, according to photographer Lauri Kangas.
Extreme cold contributes to the formation of light pillars, which can be caused even by light from car headlights.
February 18, 2009--"The aliens are coming!" photographer Aigar Truhins's son exclaimed upon seeing these multicolored "trumpets" of light in Sigulda, Latvia, on December 28, 2008.
