news sciences: What causes sun pillars or light pillars?

Red sunrise with yellowish to red thick column of light extending straight up from forested hills.

View at EarthSky Community Photos. | Nicholas Holshouser captured this photo from the Blue Ridge Parkway Milepost 412 in North Carolina, in the early morning of December 1, 2020. He wrote: “The first cold front of the season dropped temps into the teens (a bit below zero degrees C) along the Blue Ridge Parkway. As the fog rolled over the ridge behind me, sunlight (from below the horizon) began illuminating the cold air and created a beautiful sun pillar. The sun pillar extended even above the clouds. Easily the most perfect example of a sun pillar I’ve ever witnessed.” Thank you, Nicholas!

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 5 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!

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Orange sun rising over the ocean, with tall sun pillar above, brghter and dimmer as it passes through horizontal clouds.

View at EarthSky Community Photos. | Nancy Ricigliano at Jones Beach, New York, caught this sun pillar on March 3, 2019.

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.

2 photo, each of large sun in clouds with wide column of light above and below respectively.

Michael Busch captured this pair of photos on December 12, 2018, and wrote: “Incredible sun pillar above and then below the sun. Fire Island, New York.” Wow! Thanks, Michael.

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.

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.

Bottom view of bright orange corrugated clouds with vertical column of light.

December 7, 2018, sunrise from Independence, Oregon, via Kathryn M. Bennett. Notice the sun pillar! Kathryn said she literally ran outside to get images before having to leave for work. “As I was photographing, I noticed the sun pillar.”

Pillar of light coming up from dark clouds against a yellow sunset.

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

Yellow and red horizontal sunset clouds with narrow vertical light pillar from top edge of sun at horizon.

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

Red and yellow clouds above crashing waves on rocky coast with pillar of light on horizon.

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!

Drawing of two thick, flat blue hexagons.

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.

Two light pillars fading into dark sky over divided highway streaked with white and red lights.

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.

Two big, blurry birds flying under orange sunset clouds with light pillar in background over a lake.

Canada geese look like ghosts as they fly though a sun pillar – January 28, 2017 – in Quakertown, Pennsylvania.

White, blue, and red sky with vertical pillar of light coming straight up from behind bare trees.

View larger. | Sun pillar seen by EarthSky Facebook friend Colin Chatfield on November 6, 2012, in Saskatoon, Saskatchewan, Canada. Thank you, Colin.

Short, wide verical column of light in open blue sky between red-orange clouds.

View larger. | Sun pillar seen by EarthSky Facebook friend Shanna Dennis. Thank you, Shanna.

Vertical column of light amid majestic orange sunset clouds.

Photo via EarthSky Facebook friend Kim Smith, taken in February 2013. She wrote: “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 in the right conditions can be seen extending upwards or downwards from the sun or other bright light sources. They’re caused by light reflection from hexagonal ice crystals drifting in Earth’s atmosphere.

from EarthSky https://ift.tt/2QDAIdz