It’s a scientific accomplishment that would make headlines even if amateurs had not taken part—or if it had received a less remarkable name. Scientists have not discovered a new aurora-related phenomenon since the early 1990s, said Lawrence Lyons, a professor of physics at UCLA who was not connected with the paper.

“I’ve never seen something this new discovered by citizen scientists in the aurora before,” he told me. “Finding something you can identify as a new structure in the aurora is relatively unusual. The last major thing was poleward boundary intensification, and you can find that name used back over 20 years ago.”

The discovery is all the more remarkable because Steve’s pioneers did not intend to find a new phenomenon: They just wanted to admire nature. Take Chris Ratzlaff, for instance. Four years ago, he went out one night to watch and photograph the aurora near his home in Calgary, Alberta.

By itself, this was nothing unusual. Though Ratzlaff is a software developer by day, he helps run a Facebook group for aurora watchers in his province, and he has traveled around the country to see the lights. “I don’t make any income from it, but it’s certainly more than a hobby,” he told me, of his aurora watching. “So it’s more accurate to call it an obsession than a profession.”

Nor did that particular night seem unusual at first. Ratzlaff was entranced by a brilliant display of dancing green ovals far to the north. When the lights lulled, he looked around to admire the stars for a moment.

“And there was this streak against the sky,” he told me. “It was pretty dim, it wasn’t very bright, but it was noticeable.” At first, he thought the streak was an airplane contrail: Calgary sits under several passenger-jet routes. But when he pointed his camera at it and took a long-exposure photo, the streak seemed to glow in the image. “It was clear the thing was emanating light, which contrails obviously don’t do,” he said.

The next day, back at home, he shared the image with a few other aurora-watching Facebook groups around Canada. Other people had seen the purple streak too, some as early as 2010. (Later, researchers would find descriptions and images of the streak from much earlier, though these had gone unnoticed by the scientific community.) One seasoned sky watcher told Ratzlaff that the streak was called a “proton arc.” Ratzlaff brought this name back to his local Facebook group, and soon photographers around Alberta were capturing images of the “proton arc” of their own.

It was not, in fact, a “proton arc”—but Ratzlaff would not learn this for another two years.

In the fall of 2014, Elizabeth MacDonald, a physicist at NASA, launched a new online project called Aurorasaurus. She and her colleagues aimed to capture social-media descriptions of the aurora, including geo-tagged photos or videos, in order to help researchers better understand the aurora. The idea came to her when she first searched Twitter during a major aurora storm in 2011.