When Ryota Suyama woke up around 4 a.m. on Tuesday, it looked as if an alien invasion had taken over the town of Canmore.
Columns of light shot into the night sky above residents’ rooftops, illuminating a backdrop of snow-capped mountains.
“It was a bit surreal,” Suyama said.
“We’ve seen northern lights a few times, but we’d never seen pillars of light… It almost felt like it was happening right in front of us, so it was absolutely amazing.”
Suyama is one of several Alberta residents who witnessed the spectacle this week, with columns of light from Spruce Grove to Calgary.
Pillars of light form on very cold, clear evenings when tiny ice crystals form in the atmosphere, according to Jeroen Stil, an associate professor in the Department of Physics and Astronomy at the University of Calgary.
On quiet evenings, the crystals are angled at just the right angle to act like little mirrors, reflecting any light beaming at them from below, like a street lamp or lighting on a commercial building.
“Even though it appears to be a pillar of light… that’s actually not true,” Stil said in a… interview on the Calgary Eye Opener.
“It’s actually an optical illusion that it looks like a beam of light is going straight into the sky.”
Like a rainbow, you could never get closer to or move through these columns of light, Stil says.
The ice crystals hang about halfway between your eyes and the so-called pillar, so as you move, the appearance of the illusion changes.
LISTENING | University of Calgary professor explains the science behind pillars of light:
You need temperatures below –20°C to form ice crystals, Stil says. But Roland Dechesne, former president of the Royal Astronomical Society of Canada’s Calgary center, says he saw them around 11 a.m.
He travels to the city for work from Vulcan County — about 50 miles southeast of Calgary — and says he sees the pillars of light at least a dozen, maybe two dozen times each winter.
A sign of garbage, light pollution
Because of the cold temperatures in the city, the rays are not uncommon, he says, but if… southern Alberta is known for windy conditionsthey are not a given.
While the beams can be beautiful, Dechesne says he actually sees them as a sign of waste.
In order for the light to bounce off the ice crystals, it must be pointed upwards.
“If you want to use a lamp, it’s usually because you want to illuminate the ground, so you want the light to shine below the horizontal,” he said.
“If you see a pillar of light, it’s because light shines above the horizon.”
Dechesne says those slanted lights are usually a waste of energy, but they can also affect wildlife.
“Most of our songbirds are actually nocturnal migrants, and some of them use visual cues from the night sky to navigate,” he said.
“These lights aren’t just on in the winter when we can see the pillars of light, they’re on all year round at night.”
Despite the light pollution, Stil says he doesn’t blame people who think they look spectacular, and the fact that people are interested in them will help raise awareness of the issue.
“The more people become aware, the easier it is to start a conversation about stray light and what it does to the environment.”