Shafts of glittering light in the skies over New England this weekend had some people wondering if they were optical illusions. Others likened the lights to beams cast from an alien spaceship.
Known as “light pillars,” the atmospheric optical phenomenon is caused “when light is refracted by ice crystals,” according to AccuWeather. Conditions have to be just right for the spectacle to occur.
The columns of light were visible across New England on Saturday night — appearing in parts of New Hampshire, Vermont, and Massachusetts.
For ice crystals to form, the conditions need to be calm and extremely cold, according to AccuWeather. The rays of light are visible when the ice crystals are close to the ground.
The source of the beams is usually man-made, such as “street lights and other ground light,” according to AccuWeather. The beams tend to take on the color of the light sources, AccuWeather said.
People marveled over the unusual sight and were quick to share photos and videos on social media.
“Light pillars! This was the coolest thing I’ve seen in NH (to date),” Christian Hammond wrote on Facebook. “I tried to capture the mystical beauty of the glittery ice falling everywhere. It was magical!”
Light pillars typically occur farther north, according to AccuWeather, and vary significantly from auroras. While auroras cover a much larger area, pillars happen close to the ground.
Because conditions have to be just right for the light pillars to appear, they are relatively uncommon, Justin Anderson, a Northern Lights photographer, told CTV News Winnipeg last year after the beams appeared in Manitoba.
“It looks like hundreds of feet for us, but really it’s going miles in the air and it looks incredible,” Anderson said. “It’s one of the coolest things you can see underneath the night sky besides the Northern Lights.”
Below are some of the photos posted over the weekend.
Shannon Larson can be reached at shannon.larson@globe.com. Follow her @shannonlarson98.