Auroras in southern Canada a possibility after 'intense' solar flare: astronomers

Toronto -

After a massive solar flare emerged from the sun on Thursday, astronomers say auroras could dazzle the skies as far south as Toronto during the Halloween weekend.

Thursday's solar flare was accompanied by a large eruption of plasma, which astronomers call a "coronal mass ejection," aimed in our planet's direction.

"(A coronal mass ejection) is basically a lot of particulate radiation being forced away from the sun at a couple of thousand kilometers a second. There's this huge wave of particulate radiation, protons and electrons primarily, heading towards Earth," York University astronomer Paul Delaney told CTVNews.ca over the phone on Friday.

NASA says the flare peaked at 11:35 a.m. EDT on Thursday and categorized it as an "X1" flare. This flare is at the lowest end of the X-class flares, the class of flares that are the most intense.

Delaney says it takes around 48 hours for the coronal mass ejection to reach Earth. By the time these particles reach our planet, most of them get deflected by the Earth's magnetic field. However, some of these particles can get caught within the poles.

"These energetic particles interact with the particles in the Earth's atmosphere, the atoms and molecules there, and cause the northern lights," said Ilana MacDonald, an astronomer with the University of Toronto's Dunlap Institute for Astronomy and Astrophysics.

The northern lights are typically only visible around the Arctic. But a strong solar flare could result in the auroras being visible in southern Canada.

"It's hard to tell because these solar flares are very unpredictable and how they actually will interact with the earth," MacDonald told CTVNews.ca over the phone on Friday. "But if it directly hits the earth, then yes, certainly, you'd be able to see northern lights from southern Canada."

Delaney says the auroras "might be visible" as far south as Toronto on Saturday or Sunday. NASA also says the auroras may be visible as low as Pennsylvania, Iowa and Oregon.

The frequency of strong solar flares has also been increasing as we head towards what astronomers call a "solar maximum," which is the highest point of the sun's 11-year cycle and has the greatest amount of activity inside the sun, Delaney says.

If you're hoping to catch the northern lights this weekend, MacDonald recommends seeking an area with low light pollution.

"The northern lights tend to be very diffuse and cloudy looking. If you're somewhere like Toronto that has a lot of light pollution, then there's a much smaller chance that you'd be able to see it," she said.

Strong solar flares also carry the risk of knocking out electrical power grids and the internet. However, Delaney says that's unlikely with this solar flare, given its strength.

"It certainly is possible, but not likely with and X1 flare. An X3, X4 or X5 flare? Sure, if we were in the crosshairs of the coronal mass ejections."