Northern lights to continue despite lessening sun activity
With solar cycle entering 11-year decline, president of Astronomy North says show will go on
Joseph Tunney
Northern News Services
Thursday, September 1, 2016
SOMBA K'E/YELLOWKNIFE
Predictions that solar activity is on the decline might depress aurora enthusiasts but have no fear, the dancing lights that keep Yellowknife's skies beautiful aren't going anywhere.
The aurora borealis during a sub-storm Aug 25, 2016, approximately 20 minutes after midnight. James Pugsley, president of Astronomy North, said the time the hours around midnight are typically the best times to see the northern lights. - photo courtesy of James Pugsley
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"There's this common belief that during periods of low solar activities there are no auroras," said Astronomy North president James Pugsley. "That's not true."
With it being the beginning of another aurora viewing season, Pugsley wants people to know that Yellowknife's position on the 62nd parallel gives people the perfect vantage point to enjoy the aurora on almost every night of the year - as long as it's dark and the skies are clear.
Northern lights are created when solar winds interact with particles in the earth's atmosphere. The type of particles the wind interacts with determines the colour of the aurora. While solar winds are pretty well constant, sunspot activity sends large bursts of electro-magnetic energy outwards from the sun, which in turn causes geo-magnetic storms in the Earth's atmosphere. These storms are what cause nights of extremely bright, active Northern lights.
The sun goes through 11-year cycles of sunspot activity, with periods of increased or reduced activity referred to as the solar maximum and solar minimum, respectively.
The last solar maximum was in 2013, meaning the amount of intense solar activity should be trending towards the cycle's low in 2019 or 2020.
While exact predictions are difficult, Pugsley said usually it's only the intensity, not the frequency, of aurora that decreases.
"You can't say anything for certain when it comes to the aurora," he said, describing it during the minimum as tending to be more "diffuse."
Furthermore, he said spectators can still potentially see some intense, bright and active aurora during the minimum - it's just that such displays become less common.
This is because Yellowknife is located in a good spot on the aurora oval. The aurora oval refers to the region of Earth that experiences auroras - it moves and stretches depending on conditions. However, Yellowknife is located under a dominate magnetic field line, meaning while the aurora may move south or north, it's still visible here "regardless of whether the sun is active or not," said Pugsley.
While solar winds are gently grazing Earth all the time, sub-storms - natural cycles of a build-up and release of energy caused by this constant bombardment - happen approximately every four hours.
These sub-storms can cause aurora so bright it's possible to read a book under the Northern lights for a few minutes, according to Pugsley.
He said misconceptions about how solar cycles influence aurora could hurt Yellowknife tourism. If people think there won't be any aurora, tourists may decide it's not worth visiting the North during the minimum, he said, which is why he believes educating people both locally and abroad about the aurora is important.
"It's just taking advantage of what's best described as Niagara Falls in the sky," he said. "Yellowknife is extremely well positioned to benefit from this opportunity."
