The North is known for its dazzling aurora displays where ribbons of colour can be seen dancing across the sky on clear winter nights. A recent study from the University of Alberta is revealing more about the science behind that phenomenon and how the northern lights may differ from their southern cousins.
Aurora borealis – the northern lights – and aurora australis – the southern lights – are both caused by gas in the Earth’s atmosphere colliding with electrically charged particles from the sun.
Ivan Pakhotin, a postdoctoral researcher and lead author of the study, explained the sun sends out streams of charged particles through what’s called solar wind. While the Earth’s magnetic field shields it from most of those particles, some get trapped and are funnelled to the magnetic poles.
Until recently, it was believed that electromagnetic energy from space was distributed evenly among the Earth’s north and south poles, but researchers have found space weather actually favours the North.
“It’s interesting. It’s unexpected,” Pakhotin said. “Plasma is a fickle beast full of surprises … It’s great that we have this natural laboratory in near-Earth space to study plasma behaviour – even though it still manages to surprise us in many ways.”
Pakhotin said researchers believe more space weather energy is distributed to the North because the north pole is closer to the Earth’s rotational axis than the south pole.
While scientists see a link between this discovery and the aurora, Pakhotin said it’s unclear how exactly it’s affecting the lights in the North compared to the south.
“It’s possible that there may be more auroras in the North or it’s also possible that we might just be seeing kind-of the residual energy that’s left over after the auroral acceleration has taken place,” he said. “So it might actually mean, at least on the night side, there’s more auroras in the south.”
“In general, we’re very lucky to live here in Canada,” he continued. “You can see auroras even as far south as Edmonton. You just don’t get that kind-of coverage in Eurasia at similar latitudes.”
Beyond beautiful light shows, space weather can also negatively impact communication networks, navigation systems, and satellites. In serious cases, it can even cause transformer failures and power outages like the 12-hour blackout in Quebec in 1989.
“That’s why we study space weather. It’s obviously very important to us here on Earth,” Pakhotin said.
“Canada is a big country with long stretches of power lines running through hundreds of kilometres … This country takes space weather pretty seriously.”
Researchers made the discovery using data from an electric field instrument developed at the University of Calgary, along with the European Space Agency’s Swarm satellite constellation.
Pakhotin said the study “puts Canadian technology on the map across the world” and has potential implications for previous research that relied on the assumption that electromagnetic energy is evenly distributed among the magnetic poles.