Northern lights go south: Effect might last several more years, expert says

Sun is at its maximum activity so aurora borealis is extending to more areas

This public beach in Ottawa is where hundreds of people viewed the northern lights on Oct. 10. The aurora borealis has been uncharacteristically active in southern parts of Canada in October. (Photo by Christine Mastroianni, special to Nunatsiaq News)

By Arty Sarkisian

The northern lights seem to be getting a little less northern lately.

The spectacle is usually only visible in the Arctic regions of the world. However, images of the lights taken from southern regions have filled social media feeds across North America in the past weeks, most recently on the evening of Oct. 10.

In fact, the Arctic will share the lights with the south more often in the coming months and even years, says Kathryn McWilliams, one of Canada’s leading aurora experts.

That’s because the sun is going through the most active phase of its 11-year solar cycle, said McWilliams, a professor at the University of Saskatchewan. She’s also director of SuperDARN Canada, or Super Dual Auroral Radar Network, which measures space weather, including the aurora.

McWilliams is Canada’s only honorary fellow of the UK’s Royal Astronomical Society for her work in the field.

The northern lights visibility forecast for Oct. 17. (Screenshot courtesy of Space Weather Prediction Centre)

In an interview, she explained the sun has a magnetic field which, like the Earth, has south and north poles. Once every 11 years the poles flip, making the sun a “big giant mess” during which time it produces more energy than it normally would.

“We’ve probably got a couple of years of high activity ahead,” she said.

Northern and southern lights are caused by energized particles from the sun — the solar wind — hitting the atmosphere near the Earth’s poles.

The solar wind energizes oxygen and nitrogen atoms in the upper atmosphere, causing them to glow in various colours, from green to red.

“We used to have a really good analogy for this,” McWilliams said.

“A big old tube TV, with the electron gun in the back, is like a miniature version of how the aurora works.”

In tube TVs — which stopped being produced nearly 15 years ago — charged particles come out of the tube and in the back hit the screen to make it glow.

In the case of the northern lights, the atmosphere plays the role of the screen and the glow happens somewhere between 100 and 300 kilometres above ground.

Many Canadians won’t need to wait long for their next chance to view the northern lights. The U.S. Space Weather Prediction Centre forecasts high visibility of northern lights across Canada for the nights of Oct. 17 and 18, mostly over the prairies all the way down to the U.S. border.

Solar cycles recorded since 1749. (Screenshot courtesy of Space Weather Prediction Centre)

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(1) Comment:

  1. Posted by S on

    In the late Seventies and early Eighties the Northern Lights were spectacular and frequent in Edmonton

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