What is a sun pillar, or light pillar?

What are sun pillars, and light pillars?

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!

Available now! 2023 EarthSky lunar calendar. A unique and beautiful poster-sized calendar showing phases of the moon every night of the year! And it makes a great gift.

What makes them?

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.

Sun pillar photos from the EarthSky community

Submit your recent photo here.

More sun pillar photos from the EarthSky community

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.