A Phenomenon Called Steve: A Discovery for Citizen Science

Andrew May

Amateur photographers and “citizen scientists” had known about it for years, and they gave it the suitably proletarian name of Steve. It was the most exciting development in atmospheric physics for decades, yet mainstream researchers were the last to hear about it.

“Citizen science” is a relatively new term, but the basic concept—enthusiastic amateurs supplying data and observations to the formal scientific community—goes back a long way, particularly in aesthetically attractive fields like natural history and astronomy. The change in recent years has simply been one of scale. In today’s connected world of apps and social media, millions of people around the world can make valuable contributions through initiatives like iNaturalist, Galaxy Zoo, and Planet Hunters.

Less well known—unless you happen to live more than 60 degrees north—is Aurorasaurus, a NASA and NSF-funded project to collect and analyze sightings of the aurora borealis by the general public. One of the most spectacular and enthralling sights on the planet, the aurora is archetypal citizen science material. It’s scientifically important, too, because the visual display is caused by the interaction of fast-moving electrons ejected from the Sun—the solar wind—with the Earth’s upper atmosphere, and a bad solar storm can disrupt electronic communications. Fortunately, the Earth is protected most of the time by its magnetic field—except near the poles where the field emerges, allowing solar electrons to stream in and create auroras.

So the mechanics of auroras are well understood. That’s fine in the context of citizen science, where the aim is to amass large quantities of data for professional scientists who don’t have the time or resources to collect the data themselves. If they’re lucky, the citizen scientists might discover an unknown species of butterfly, or a previously uncharted comet—but that’s not “new science,” just an incremental addition to well understood science. It would be the same if the aurora enthusiasts had discovered a new form of aurora. But that’s not what happened with Steve, because it isn’t an aurora at all. It isn’t created by solar wind particles impinging on the atmosphere. What the citizen scientists discovered was a brand new, hitherto totally unsuspected phenomenon.

Enter Steve

Central to the Steve story is the contrast between the amateur and professional approaches to science. If you take astronomy, for example, amateurs tend to focus on the way celestial objects—planets, galaxies or whatever—look, while professional scientists are more interested in understanding how these things work. It’s the same with auroras.

Central to the Steve story is the contrast between the amateur and professional approaches to science. If you take astronomy, for example, amateurs tend to focus on the way celestial objects—planets, galaxies or whatever—look, while professional scientists are more interested in understanding how these things work. It’s the same with auroras.

Typical of academic aurora scientists—and one of the chief protagonists of our story—is Eric Donovan, an associate professor at the University of Calgary’s department of physics and astronomy. For the last 20 years he’s been using an array of cameras across Canada to photograph auroras. But he’s not interested in the images per se, or even auroras per se, so much as what they can tell him about the Earth’s otherwise invisible magnetosphere. As important as this work is scientifically, it’s hardly glamorous from an outsider’s point of view—a fact Donovan freely admits. “Unless you’re interested in something like how pitch angle diffusion of 10 keV electrons by lower band chorus near the inner edge of the plasma sheet causes patchy pulsating auroras,” he says, “then what I do is not very interesting.”¹

The turning point came in early 2016, when the Calgary scientists hosted a talk by the creator of the Aurorasaurus citizen science program, Liz MacDonald of NASA’s Goddard Space Flight Center. To Donovan’s surprise, the talk was attended by dozens of people he’d never seen before, who turned out to be members of a local Facebook group called the Alberta Aurora Chasers. They may never have heard of him, but they’d certainly heard of Liz MacDonald, who is something of a folk-hero in the amateur aurora-following community.

After the talk, the group showed Donovan some of their aurora photographs. Belying their “amateur” status, these were of stunning quality decidedly more beautiful than the images from Donovan’s own cameras, he admitted. Then one of the amateur photographers, Neil Zeller, happened to say “I took a picture of a proton arc last night.” This was no big deal for him—it was a sight the group had been photographing for years, and they always called it a proton arc. What they meant was an aurora caused, not by electrons from the Sun, but by protons.

“No, you didn’t,” Donovan replied, even before he’d seen the picture. His rationale was that everyone in the scientific community “knew” that proton auroras were much too faint to be visible. This sounds like the kind of blinkered dogmatism that mainstream scientists are often accused of, where they refuse to look at concrete evidence because it conflicts with an established theory. Donovan, however, did look at the evidence but it didn’t change his view. This wasn’t a proton aurora, or any other kind of aurora. It was something much more interesting than that.

An aurora is a wispy, shimmering curtain of light—often red or green—seen in the far north. The thing the amateur enthusiasts had been calling a proton arc was a thin band of light, pink or purple in color, stretching across the sky from east to west. Sometimes, but not always, it was accompanied by a more typical green “picket-fence” aurora. Most significantly, both these phenomena occurred further south than an aurora had any right to be. They could be seen high in the sky as far south as Calgary or London (both around 51 degrees latitude).

For Eric Donovan, it was an exciting moment. “I didn’t know what it was, but I knew it wasn’t a proton aurora,” he says. “This was fundamentally different from any phenomenon I had ever seen before in the night sky.”

If Donovan, as an expert in upper atmospheric physics, didn’t know what the photographs showed, then he was pretty sure no one else in the scientific community knew either. He did know one thing, however. There was no way the aurora chasers could go on calling this thing a proton arc, because it simply wasn’t one. He told them to think up a new name.

A week later, a post appeared on the Alberta Aurora Chasers Facebook page from one of the members, Chris Ratzlaff, saying “Why don’t we call it Steve?” This may sound pretty arbitrary, but there was a rationale behind it. As Donovan explains, “The reason why he suggested we call it Steve has to do with a children’s movie called Over the Hedge, where these animals wake up after hibernating and find the hedge. They’re scared of it, they don’t know what it is, but if they call it Steve it’s a little bit less scary.”

Steve the atmospheric phenomenon may not have been particularly scary, but it was certainly mysterious. Donovan was determined to uncover its secrets. As spectacular as the amateur photographs were, they only contained a limited amount of information. The data from Donovan’s scientific instruments potentially held more clues, but he wasn’t sure exactly what he was looking for. So he and his team spent hours scouring the data for hints of Steve. “We found this signature,” Donovan says, “this ethereal luminous feature that we thought was promising.”

Donovan’s plan was to wait for another night when this particular signature cropped up in his data, and then see if anyone spotted Steve that

night. The plan worked like a dream. Just a few weeks later, he spotted the telltale signature from a camera in Saskatchewan—and at exactly the same time one of the aurora chasers, Song Despins, snapped a photograph of Steve over Vimy, Alberta.

Donovan’s luck didn’t end there. A European Space Agency satellite—one of three, called Swarm, designed to monitor the Earth’s magnetic field—happened to fly right through the area at just that moment. It provided the strongest clue yet as to the true nature of Steve. As Donovan explains, “It corresponds to a river of very fast moving gas that’s moving at 7 kilometers per second from east to west, and it extends all the way from Hudson Bay in this instance all the way over to Alaska. If you were to look at this from space it would look like someone had reached in with a purple felt pen and drawn a line on the globe thousands of kilometers from east to west.”

In just a few months, the scientific community had gone from being blissfully unaware of Steve’s existence—despite the fact that amateur enthusiasts had photographed it for years—to having a reasonably complete physical description of it. “This was a revolution from my perspective,” Donovan says. “This represents the fact that we are in a fundamentally new era—enabled by this information technology explosion—but the new thing and the fundamentally different thing is the social media connection between these truly phenomenally talented amateur watchers of nature and scientists who tend to focus on things that we already know are there.”

Belatedly, Steve was added to the list of things scientists “already know are there.” They knew what it looked like, they knew where it appeared, they knew what it was composed of. But there was another crucial question they still needed to answer: what causes it?

From Steve to STEVE

It wasn’t until March 2018 that scientists felt the phenomenon was sufficiently well understood to publish a “discovery paper” on it, in the journal Science Advances. Like most such papers, it has a long string of authors, led by Liz MacDonald and Eric Donovan—and including, further down the list, a couple of members of the Alberta Aurora Chasers. The paper’s title doesn’t mince words about their contribution either. It’s called “New Science in Plain Sight: Citizen Scientists Lead to the Discovery of Optical Structure in the Upper Atmosphere.”

By this point, a link had been made with a previously postulated, but unobserved, phenomenon called sub-auroral ion drift (SAID). “Sub-auroral” means occurring at lower latitudes (not lower altitudes) than conventional auroras, while “drift” is something of an understatement, given that the speeds involved can reach several kilometers per second. Quoting from the paper itself:

Observations from the Swarm satellite as it crossed the arc have revealed an unusual level of electron temperature enhancement and density depletion, along with a strong westward ion flow, indicating that a pronounced sub-auroral ion drift (SAID) is associated with this structure. These early results suggest the arc is an optical manifestation of SAID, presenting new opportunities for investigation of the dynamic SAID signatures from the ground. On the basis of the measured ion properties and original citizen science name, we propose to identify this arc as a Strong Thermal Emission Velocity Enhancement (STEVE)._²

Actually, that metamorphosis of Steve into a more respectable- looking acronym wasn’t new. As early as December 2016, at a meeting of the American Geophysical Union, Eric Donovan suggested Steve needed a “backronym.” It was a member of the audience on that occasion, Robert Lysak of the University of Minnesota, who suggested “Strong Thermal Emission Velocity Enhancement.”

A second study, led by Toshi Nishimura of Boston University and published in April 2019, clarified the situation still further by delving into several years’ worth of data collected by various satellites. One of the study’s key findings—which helps explain why STEVE was overlooked for so many years—is that the green picket-fence feature commonly associated with it really is “just an aurora.” STEVE, on the other hand, is a separate phenomenon caused by different physical processes.

As one of the study’s co-authors, Bea Gallardo-Lacourt—a member of Eric Donovan’s team in Calgary—explains, “Auroras are defined by particle precipitation—electrons and protons actually falling into our atmosphere—whereas the STEVE atmospheric glow comes from heating without particle precipitation. The precipitating electrons that cause the green picket fence are an aurora—though this occurs outside the auroral zone, so it’s indeed unique.”³

The Nishimura paper also makes the point that, as fascinating as STEVE is to academics—and as alluring as it is to photographers—it has a solid practical value too. By helping scientists understand the movement of charged particles in the upper atmosphere, it casts light on the way disturbances in this region can interfere with radio communication and degrade GPS signals. As with STEVE’s original discovery, this insight won’t come from the academic community alone. Quoting Nishimura, “As commercial cameras become more sensitive, and increased excitement about the aurora spreads via social media, citizen scientists can act as a mobile sensor network, and we are grateful to them for giving us data to analyze.”

Bea Gallardo-Lacourt also acknowledges the value of amateur contributions. “Although scientists are doing the research for STEVE, this really is a discovery by the photographers,” she says. “For me, this is the most romantic way of doing science.”⁴

Was it there all along?

Back in 2018, when the first academic papers were appearing on the subject of STEVE, Gallardo-Lacourt remarked that “Right now, we know very little about it. And that’s the cool thing, because this has been known by photographers for decades. But for the scientists, it’s completely unknown.”⁵

This raises an interesting issue. It seems inconceivable that STEVE is a newly evolved phenomenon, even in the few decades that amateur enthusiasts have been photographing it. Surely—like the aurora itself—it must have been around since time immemorial? This thought prompted a group of researchers, led by Mark Bailey of the Armagh Planetarium, to scour a variety of historical records for sightings that might retrospectively be identified as STEVE. In the resulting paper, published in the journal The Observatory in October 2018, they write: “Some previously unidentified atmospheric, meteoric or auroral ‘anomalies’ can now be recognized as examples of STEVE, and therefore as part of a broad spectrum of occasional auroral features that may appear well below the region of magnetic latitudes represented by the traditional auroral oval. This highlights the contributions of ‘citizen scientists’ dating back hundreds of years.”⁶

In all, the paper lists over 50 observations, from antiquity to the early 20th century, that might, with varying degrees of certainty, be ascribed to STEVE. Here are just a few examples:

• England, March 1717: “Around 11 pm, a long, narrow streak of light extending east and west, initially shining very bright but fading after 8 or 9 minutes.”
• Eastern USA, March 1781: “Auroral arch stretching from nearly due east toward the west-north-west.”
• England, March 1847: “A brilliant band of light suddenly appeared, extending from the western horizon upwards across the zenith to at least 20 or 30 degrees beyond.”
• Ontario, Canada, August 1916: “Immense arc or ribbon of light.”

These reports, from the last few centuries, were made by amateur astronomers in relatively sober scientific terms. Going back to pre-scientific times, the language becomes more fanciful. Here are two examples from 12th century England: “A flying fire from the east toward the west, like no small city” (1101) and “A light shone from east to west … some affirmed they saw a fiery dragon at the same hour with a crisped head” (1177). And one from Italy, from as far back as 204 BC: “At Setia a torch was seen to be stretched out from the east to the west.”

Such accounts are reminiscent of the lists of strange things seen in the sky complied by Charles Fort—the 20th century’s notorious “prophet of the unexplained.” Yet with the benefit of hindsight, it’s possible to see how they might be garbled descriptions of STEVE. It leads one to wonder how many other anomalous sightings have perfectly natural explanations just waiting to be found—by citizen scientists if not by mainstream science itself.

ANDREW MAY has an MA from Cambridge University and a PhD in Astrophysics. His 30-year professional career spanned academia, the civil service, and the defense industry. He now works as a freelance author in the southwest of England. His most recent books are Astrobiology, in the Hot Science series from Icon Books, and Fake Physics, in the Science and Fiction series from Springer.