By Maria Temming. February 22, at am. Zeller was on a family vacation in British Columbia, Canada. One August night, he glimpsed something strange while photographing the northern lights. A band of purple light ran east to west across the sky. This was south of the auroras that made up the northern lights. The purplish-white streak looked almost like the vapor trail of an airplane β yet not quite. Intrigued, Zeller swiveled his camera toward the mystery light. Later, he found that other aurora chasers online had seen similar purple streaks.
They called them proton arcs. The term referred to known features of the northern and southern lights. But a couple of years later, Zeller and his fellow photographers would learn that they actually had been documenting a natural light show that was yet unknown to science. The revelation took place in a pub in Calgary, Canada.
A group of aurora-chasers were hanging out with researchers from the University of Calgary. Donovan replied that this was impossible. Since no one had a clue what this ribbon of purple could be, aurora chasers started calling it Steve.
Scientists later turned that name into an acronym. And recently, citizen-science photos have raised questions about how STEVE might be related to another non-aurora light show known as a stable auroral red arc. The auroras that make up the northern and southern lights drape the sky with green, blue and red hues. They form when charged particles rain down into the atmosphere from the magnetic bubble around Earth β our magnetosphere.
This causes those oxygen and nitrogen atoms to glow green, red and blue. STEVE, on the other hand, paints the sky with a brush of purple. And it shows up closer to the equator. Satellite data have shown that STEVE is likely powered by a river of charged particles rushing through the atmosphere.
