Sun pillars and light pillars are beams of light that extend vertically upward (or downward) from a bright light source, such as the sun or another bright light low on the horizon. They can be 5 to 10 degrees high and sometimes even higher. In fact, they might lengthen or brighten as you gaze at them.
They’re beautiful and wondrous. And they’re also the source of some UFO reports!
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 them?
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. However, you might even see a sun pillar when the sun is below the horizon. On the other hand, you can see light pillars at any time of night.
They’re called sun pillars when the sun helps make them. But the moon or even streetlights can create this light phenomenon, too, in which case the name light pillar is more appropriate.
UFO reports, and more resources
These pillars of light often prompt people to report sightings of UFOs. They can sometimes look strange! In fact, light pillars trigger a lot of UFO reports 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.
By the way, Les Cowley’s great website Atmospheric Optics is a wonderful place to go and learn more about sun pillars.
Bottom line: In the right conditions, you can see vertical shafts of light extending upward or downward from the sun or other bright light sources. These are called sun pillars or light pillars, and are caused by light reflecting from hexagonal ice crystals drifting in Earth’s atmosphere.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.
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