Canadian citizen scientist photographers spotted a fleeting type of aurora not seen before, dubbed “Steve,” and scientists have started working out what’s causing them.
While the northern and southern lights have dazzled watchers of the night sky for millennia, vigilant citizen scientist photographers found another type of aurora over the past few years: a short-lived shimmering purple ribbon of plasma. Their intriguing discovery drew the attention of space scientists, who have just begun to study them.
“Dedicated aurora chasers, especially from Alberta, Canada, were out in the middle of the night, looking north and taking beautiful photos. Then farther south they happened to see a faint narrow purple arc as well,” says Elizabeth MacDonald, a space physicist at NASA Goddard Space Flight Center in Greenbelt, Maryland. There’s different physics behind those purple aurora, she says.
MacDonald led a team who observed the aurora by sending one of the European Space Agency’s Swarm satellites through it. The results suggest they’re a manifestation of accelerated and heated charged particles coming from the sunthat interact with a particular part of the Earth’s magnetic field in the ionosphere. The team published their findings in Science Advances Wednesday.
The citizen scientists weren’t sure about what they’d seen, so they called the strange aurora structure “Steve.” The name caught on, and MacDonald and her team kept it, proposing the backronym Strong Thermal Emission Velocity Enhancement (STEVE). While scientists had known about lower-latitude currents of charged particles for decades, they had no idea that they could produce auroras visible to the eye. But now that people have smartphones and digital cameras more sensitive than what scientists had back then, they can pick out these rare aurora, which last only about an hour.