Enjoying EarthSky? Subscribe.

231,652 subscribers and counting ...

What is a sun pillar, or light pillar?

Sun pillars, or light pillars, are shafts of light extending from the sun or other bright light source. They’re caused by ice crystals drifting in Earth’s air.

EarthSky Facebook friends occasionally post beautiful photos of sun pillars, or light pillars. For example, there was a beautiful one seen from the U.S. West Coast on March 20, 2016 … a beautiful prelude to the first full night of spring. Sun pillars are vertical shafts of light that extend upward (or downward) from a bright light source, such as the sun or other bright light low on the horizon. They can be five to 10 degrees tall and sometimes even higher. They might lengthen or brighten as you gaze at them.

They’re beautiful and wondrous. They’re also the source of some UFO reports!

Joe C. Tabb and his wife caught this amazing sun pillar at sunset on May 10, 2016. A storm had recently passed.

Joe C. Tabb and Dawn Tabb caught this amazing sun pillar at sunset on May 10, 2016. A storm had recently passed.

U.S. West Coast got an amazing sun pillar on the first evening of spring. Thanks, Lyle Evans

The U.S. West Coast got an amazing sun pillar on the first evening of spring, 2016. Photo by Lyle Evans in Highland, California.

Another shot of the beautiful sun pillar seen on March 20, 2016, from the U.S. West Coast.  This one is from Chris Levitan Photography.  Thanks, Chris!

Another shot of the beautiful sun pillar seen on March 20, 2016, from the U.S. West Coast. This one is from Chris Levitan Photography. Thanks, Chris!

Sun pillars or light pillars are formed by reflection from hexagonal plate-like ice crystals in Earth’s air. These crystals drift through the atmosphere with a horizontal orientation, gently rocking from side to side as they fall. Diagram via University of Illinois.

Sun pillars or light pillars form when sunlight (or another bright light source) reflects off the surfaces of millions of falling ice crystals associated with thin, high-level clouds, for example, cirrostratus clouds. The ice crystals have roughly horizontal faces. They are falling through Earth’s atmosphere, rocking slightly from side to side.

When is the best time to see a sun pillar or light pillar? You’ll most often see sun pillars when the sun is low in the western sky before sunset, or low in the east just after the breaking of dawn. You might even see a sun pillar when the sun is below the horizon. Light pillars can be seen at any time of night.

View larger. | Wesley Liikane in Severn Bridge, Ontario captured these light pillars on December 23, 2013.   See more photos by Wesley at Cowboy with a Camera on Facebook.

View larger. | Wesley Liikane in Severn Bridge, Ontario captured these light pillars on December 23, 2013. See more photos by Wesley at Cowboy with a Camera on Facebook.

They’re called sun pillars when the sun helps make them. But this the moon or even streetlights can create this light phenomenon, too, in which case the name light pillar is more appropriate.

These pillars of light often prompt people to report sightings of UFOs. They can sometimes look strange! There are said to be a lot of UFO reports caused by light pillars over Niagara Falls, where the mist from the rush of descending water interacts with the city’s many upward facing spotlights. Light pillars do appear frequently over Niagara Falls, especially during the winter.

As always, the great website Atmospheric Optics is a wonderful place to go and learn more about sun pillars.

Sun pillar seen by EarthSky Facebook friend Colin Chatfield on November 6, 2012 in Saskatoon, Saskatchewan, Canada. Thank you, Colin. Click here to expand image.

Sun pillar seen by EarthSky Facebook friend Shanna Dennis. Thank you, Shanna. Click here to expand.

Photo credit: EarthSky Facebook friend Kim Smith, taken February 2013. She says “My first ever sun pillar! We don’t often see them here in Walker Creek, Arkansas. I am glad I was out to photograph the sunset today when this occurred.” Thanks Kim!

Bottom line: Sun pillars, or light pillars, are vertical shafts of light that can sometimes be seen extending upwards or downwards from the sun or other bright light source. They’re caused by light reflection from hexagonal ice crystals drifting in Earth’s atmosphere.

Deborah Byrd

MORE ARTICLES