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Not all science is performed by people in white lab coats under the fluorescent lights of academic buildings. Sometimes the trajectory of the scientific record is altered forever inside a pub while drinking a pint of beer.
Such is the case of the broad violet and green lights that can float above the horizon in the northern hemisphere. The phenomenon looks like an aurora, but in reality it is something completely different.
His name is Steve.
The rare light show has caused a bit of a stir this year as the sun enters its most active period, increasing the number of dazzling natural phenomena appearing in the night sky and leading to new reports of people seeing Steve in areas where it does. They do not usually appear, like parts of the United Kingdom.
But about eight years ago, when Elizabeth MacDonald, a space physicist at NASA’s Goddard Space Flight Center, was in Calgary, Alberta, for a seminar, she had never seen the phenomenon in person. And she still didn’t have a name.
In fact, few scientists who actively study auroras and other night sky phenomena have witnessed a Steve, which appears closer to the equator than auroras and is characterized by a purplish-pink arc accompanied by green vertical stripes.
After MacDonald gave a talk at a nearby university, he met up with some citizen scientists (mostly photographers who spend their nights waiting to capture the next stunning image of colors dancing in the Canadian sky) at the Kilkenny Irish Pub.
“I had already been communicating with local Alberta aurora hunters (on) a Facebook group, which was pretty small at the time,” MacDonald said, “but very interested in sharing their observations and interacting with NASA.”
Photographers came with their photographs in hand, eager to show off the mysterious light show they had captured.
Naming the show
At the time, “we didn’t know exactly what it was,” MacDonald said of the phenomenon seen in the images.
Neil Zeller, a citizen scientist or photography subject matter expert, as photographers who chase auroras are sometimes called, was at that meeting.
“I started detecting what we used to call a proton arc in 2015,” Zeller said. “It had been photographed in the past, but misidentified, so when I attended that meeting at the Kilkenny Pub… we started a little discussion about (whether) I had seen a proton arc.”
Dr. Eric Donovan, a University of Calgary professor who was in the pub with MacDonald that day, assured Zeller that he had not seen a proton arc, which according to a paper Donovan later co-authored is “subvisual, broad and diffuse,” while Steve is “visually bright, tight and structured.”
“And the conclusion of that night was, well, we don’t know what this is,” Zeller said. “But can we stop calling it a proton arc?”
Shortly after that pub meeting, another aurora chaser, Chris Ratzlaff, suggested a name for the mysterious lights on the group’s Facebook page.
Group members were working to better understand the phenomenon, but “I propose we call him Steve until then,” Ratzlaff wrote in a February 2016 Facebook post.
The name was taken from “Over the Hedge,” the 2006 DreamWorks animated film in which a group of animals are frightened by a towering leafy bush and decide to refer to it as Steve. (“I’m a lot less afraid of Steve,” declares a porcupine.)
The name stuck. Even later the phenomenon could be better explained. Even after the explanations for Steve began to take shape in scientific papers.
Scientists later developed an acronym to go with the name: Strong Thermal Emission Velocity Enhancement.
And that meeting in a small Canadian pub was a turning point.
“That was the in-person meeting that was one of the pieces that gave him the most impetus to eventually collect more and more observations in an increasingly rigorous way so we could correlate them with our satellite,” MacDonald said.
What is Steve?
Finally, MacDonald said a satellite directly observed Steve, collecting crucial data and leading to a 2018 study that suggested the lights are a visual manifestation of something called subauroral ion drift, or SAID.
SAID refers to a narrow flow of charged particles in Earth’s upper atmosphere. Researchers already knew SAID existed, MacDonald said, but they didn’t know that it could occasionally be visible.
Steve is visually different from auroras, which are caused by electrically charged particles that glow when they interact with the atmosphere and appear as dancing ribbons of green, blue or red. Steve, if it is caused by SAID, it is made up of pretty much the same stuff. But he appears at lower latitudes and appears as a mauve streak of light accompanied by distinctive green bands, often called fences.
Steve can be frustratingly difficult to spot, appearing alongside the auroras with little regularity. Sometimes spotting Steve is a matter of luck, said Donna Lach, a photographer who lives in the Canadian province of Manitoba.
Lach has seen and photographed Steve approximately two dozen times, a rare achievement in the world of celestial photography. He said he uses the family farm on remote land in southern Manitoba where there is little to no light pollution.
She always checks the space weather before leaving. She’s looking for conditions to be at least Kp3, a space weather index that ranges from Kp0 to Kp9, with higher numbers indicating more activity.
It appears, Lach said, that the phenomenon begins with the SAR Arc, a stable red auroral arc, which appears near the auroral oval.
“It may eventually migrate south… toward the equatorial side of the aurora and form a Steve,” Lach said.
A Steve will always appear next to an aurora, Lach and Zeller said, but not all auroras include a Steve.
Where and how to see Steve
The Earth is entering a period of increased solar activity, or solar maximum, which occurs about every 11 years, MacDonald said.
During this time, viewers can expect more visible light shows in the sky and potentially the opportunity to witness Steve at low latitudes. Light phenomena have been observed as far south as Wyoming and Utah, he said.
“There have been recent storms that have been visible across the U.S., just a little bit, even as far as Death Valley,” MacDonald said. “And recently, the one in November… was visible at its southernmost point over Turkey, Greece and Slovakia, and even in China, which is very rare.”
However, Steve is best seen through the lens of a camera.
To the naked eye, it may appear to be nothing more than a faint contrail from an airplane crossing the sky, Zeller and Lach noted, and it can be easy to miss.
The cameras are much more sensitive to light and capture Steve’s vibrant colors through their lenses.
Even a phone camera can work, MacDonald added.
“This is the first solar maximum, I would say, where most people’s cell phones can take a good photo of the aurora,” he said.
According to Zeller and Lach, the Steve phenomenon is most likely to be captured around the spring and autumn equinoxes. (This year’s fall equinox occurred on September 23.)
“I don’t think it’s Steve that occurs more during the equinox, but it’s well known that larger auroral storms occur closer to the equinoxes,” MacDonald said. And because Steve tends to appear alongside the aurora, the phenomenon is most likely to be observed in March or September.
Zeller and Lach said they usually see Steve between the afternoon and midnight.
“It’s not something that lasts all night,” Zeller said. “The longest running time of Steve I’ve ever seen was an hour from start to finish.”
Zeller added that he waits for an aurora storm to begin to subside before turning his camera east (from his vantage point in Canada) or up, and then “you start to see this purple river.”
That’s Steve.
How to become a citizen scientist
MacDonald encourages anyone interested in photographing auroras (or a Steve) to participate in online communities. Aurorasaurus, a website that connects photographers with scientists, is a project he cares deeply about and highlighted its crucial role in helping scientists formally identify Steve.
Photographs contributed by the public constantly help scientists improve their understanding of these light shows, he said.
“Scientists are not as good aurora hunters as the passionate public,” he said. “We don’t stay up all night, nor are we photographers.”
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