Update March 16, 2018: A study in Science Advances confirms that "Steve" is not a normal aurora. Scientists said that this phenomenon is an "optical manifestation" of a "subauroral ion drift," a fast-moving stream of extremely hot charged particles. In a press release, lead study author Liz Macdonald of NASA's Goddard Spcae Flight Center said, "Steve can help us understand how the chemical and physical processes in Earth's upper atmosphere can sometimes have local noticeable effects in lower parts of Earth's atmosphere. This provides good insight on how Earth's system works as a whole." Steve also now has an official name: Strong Thermal Emission Velocity Enhancement, or STEVE.
Facebook is a place to share dramas and dog pictures, hit “like” and watch weird events unfold live. But for a group of amateur skywatchers, the social network is also a place to share information about what people spy in the sky. And thanks to a group of Canadian aurora enthusiasts, an entirely new type of atmospheric phenomenon has been documented.
It’s called Steve, and its origins are a bit more exciting than its straightforward name would suggest. The Alberta Aurora Chasers Facebook group first spotted the phenomenon last year, reports Gizmodo’s George Dvorsky, and has been collecting photos of Steve sightings. The name Steve reflects their confusion about the phenomenon’s origins, Dvorsky writes, and reminded someone of the movie Over the Hedge “in which a character arbitrarily conjures up the name Steve to describe an object he’s not sure about.”
When they weren’t calling the purple, ribbon-like light Steve, the Facebook group referred to it as a “proton arc,” notes ABC News. But when a Canadian physicist and astronomer who studies aurorae looked at the photos, he suspected something more was afoot—especially since proton aurorae, which happen when protons from solar winds hit Earth's magnetic field, are usually too dark to be visible.
Eric Donovan and his colleagues at the University of Calgary turned to the big guns to figure out just what was going on. They used data from the European Space Agency’s Swarm mission, which comes from a constellation of satellites that measure the Earth’s magnetic field.
Donovan was able to pinpoint Swarm data taken while a satellite flew through the Steve phenomenon, according to an ESA press release. The data didn’t show a proton aurora. Instead, it showed something that had never been observed before: a temperature spike of over 5400 degrees Fahrenheit in a spot about 186 miles above Earth’s surface combined with a gas ribbon over 15 miles wide that was flowing west more slowly than the other gases that surrounded it.
The phenomenon may have been newly spotted, but it turns out it’s pretty common. And Donovan tells Dvorsky that he has an idea of how it gets its unique color and shape—but won’t spill the beans until an upcoming paper is published.
While you wait, why not share a picture of Steve on Facebook? You can find plenty in the Alberta Aurora Chasers’ group—or head to Canada to snap Steve for yourself. Just look for the like-worthy band of purple light.