Aurora phenomenon named Steve explained

A unique light formation in the aurora borealis, discovered last year and named "STEVE," is beginning to be understood by scientists as it is studied more.

STEVE is a violet-mauve arc of light with touches of green. While auroras usually resemble large folds of light that move horizontally across the sky, STEVE is a vertical streak that appears at much lower latitudes than the northern lights usually do.

STEVE works differently from the auroras that we usually picture when we think of the northern lights. These auroras form when charged particles from the sun accumulate at Earth's magnetic poles. The charged particles interact with neutral particles in Earth's atmosphere to produce colors. Scientists once thought streaklike phenomena like STEVE were caused by proton activity and called them "proton arcs," but the auroras created by proton activity are invisible to the human eye. They now say that STEVE is caused by a very hot, fast-flowing stream of ions, in a study published in March.

The name STEVE is a "backronym" — it now stands for "Strong Thermal Emission Velocity Enhancement," a name given by the scientists that studied it, which didn't originally stand for anything. STEVE's discoverers, citizen scientists in Alberta, Canada, were inspired by the animated movie Over the Hedge, in which forest animals discover a hedge and decide to call it "Steve," never having seen it before or knowing what it is.

Thanks to coordinated photography efforts from citizen scientists in a Facebook group called “Alberta Aurora Chasers,” as well as data from scientific instruments, scientists have been able to document and study this phenomenon with a thoroughness not possible until very recently.

"In 1997, we had just one all-sky imager in North America to observe the aurora borealis from the ground," said Eric Donovan, a researcher at the University of Calgary in Canada.

"Back then, we would be lucky if we got one photograph a night of the aurora taken from the ground that coincides with an observation from a satellite. Now, we have many more all-sky imagers and satellite missions like Swarm, so we get more than 100 [observations] a night."

Phenomena like STEVE are neither new nor rare, but the ability to investigate them so thoroughly from all fronts is only possible with the information age.

“[The research was possible] thanks to ground-based observations, satellites, today's explosion of access to data, and an army of citizen scientists joining forces to document it,” said Donovan. “We really are in a truly new era.”