As particles of sun plasma hurtled through space and toward the earth Tuesday night, southern Canadians had the best view to catch a rare glimpse of the impact - the tangle of red and green light called aurora borealis, which is usually reserved for northerners.
"We have the front seat on the aurora," said Eric Donovan, a Calgary physics and astronomy professor who tracks and captures images of Canada's Northern Lights.
The Northern Lights are caused by charged particles from the sun meeting with the earth's magnetic field. Canada is optimally located within the auroral oval - a ring of electric activity that stretches across most of Canada's North, parts of northern Europe and the uppermost regions of Russia. Although the Northern Lights are always present, Canadians have the best chance of seeing them because of the oval's proximity to places like Yellowknife, Fort McMurray and Moose Factory.
And for the first time in years, the Northern Lights were expected to be clearly visible farther south - as far as the northern U.S. - due to an explosion on the surface of the sun on Sunday that blasted ionized atoms into space. Although these coronal mass ejections happen regularly, the sun has been fairly inactive since 2001, when it last reached a period scientists call "solar maximum." The sun runs on a cycle that usually lasts 11 years.
Prof. Donovan said the sun is coming out of the longest period of "solar minimum" in recent history. Without many solar events like Sunday's explosion, the Northern Lights have largely only been visible in the Far North.
"I used to ride home from and I'd see the aurora every fourth or fifth night," he said. "And I haven't seen the aurora with my own eyes in two years."
Leon Golub, an astrophysicist with the Harvard-Smithsonian Center for Astrophysics, has been tracking the sun's particles in space. He said the frequency of eruptions will likely increase over the next few years as the sun reaches its next maximum. But while the result on earth is more frequent viewings of the dancing aurorae, the radiation is a safety problem for those in space.
"These events are a major problem up there," Dr. Golub said.
When these eruptions occur, a satellite 1.6 million kilometres between the sun and the earth tracks the movement and size of the plasma. When a measurement indicates danger, controllers alert any astronauts within the dangerous area. The astronauts then have to shut themselves into protective lockers until the danger passes.
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