People in northern climes have long gazed at the wonder that is the aurora borealis: the northern lights.
Those celestial streaks of light and color are often seen on clear nights in Finland, where they’re so admired that a Finnish-language Facebook group dedicated to finding and photographing them has more than 11,000 members.
There aurora aficionados gather to discuss subjects like space weather forecasts and the best equipment to capture the northern lights.
Among its members is Minna Palmroth. She’s a physicist and professor at the University of Helsinki, where she leads a research group that studies the space weather that causes auroral emissions.
When members of the group posted photos of the auroras they’d seen and wanting to learn more, Palmroth would often reply with the aurora’s type and the scientific explanation for its form. The discussions led Palmroth and two collaborators to publish a field guide to the northern lights.
But even after the book came out, some questions remained unanswered. A few of the citizens’ photos showed a form of aurora that didn’t fit into any of the known categories. It had green, horizontal waves running in parallel. Its undulations reminding some observers of sand formations, and it was christened “the dunes.”…
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