Signs in the Heavens: An Aurora Called 'Steve'? Strange Sky Phenomenon Investigated
Eric Donovan, a researcher at University of Calgary in Canada, first heard of "Steve" while talking to members of a Facebook group called the Alberta Aurora Chasers, who coordinate to track and photograph the northern lights in the Canadian sky (Alberta is a province in western Canada). While the colorful lights of an aurora normally ripple horizontally across the sky, Steve formed a distinctive purplish or greenish vertical streak.
To learn more about it, Donovan coordinated with the Facebook group to match sightings of the feature with data from the Swarm satellites, which measure Earth's magnetic field, and ground-based scientific cameras that monitor the sky. [Paragliding Through Aurora Borealis' Beauty (Video)]
Photographer Dave Markel caught
this view of a strange aurora-like feature that appears in the skies of
northern Canada. Based on data from European Space Agency's Swarm
satellites, it appears to be a 16-mile-wide (25 km) ribbon of flowing
gas in an area whose temperature is 5,500 degrees Fahrenheit (3,000
degrees Celsius) higher than the surroundings; the gas flows at 3.5
miles per second (6 km/s) compared to a speed of 33 feet/second (10 m/s)
on either side of the ribbon. They're calling the feature "Steve."
Credit: Dave Markel Photography
Auroras are generated when charged particles ejected from the sun are drawn to Earth's north and south poles by the planet's magnetic field. There, they hit neutral particles in the upper atmosphere and let off splashes of color and light in the sky.
Astrophotographer Paul Zizka
shared this photo of the aurora phenomenon "Steve" — then called a
potential proton arc — with Space.com in October 2015. He took the photo
in Banff National Park in the Canadian Rockies on May 10, 2015.
Credit: Paul Zizka/zizka.ca
In fact, protons hitting the atmosphere produce only diffuse visible light (as researchers discussed in the Spaceweather.com article), so Donovan said he knew the phenomenon must have another cause and insisted on a new name. The aurora photographers chose to go with "Steve," Donovan said in a recent talk at a Swarm science meeting in Canada.
Within a few weeks of searching, Donovan identified signs in the ground-based data that could match a Steve-like feature, and asked the Facebook group whether anyone had spotted it — sure enough, there were photos of Steve from that very location. And better yet, one of the Swarm satellites had flown through the feature.
"As the satellite flew straight through Steve, data from the electric field instrument showed very clear changes," Donovan said in the statement. "The temperature 300 kilometers [200 miles] above Earth's surface jumped by 3,000 degrees Celsius [5,500 degrees Fahrenheit], and the data revealed a 25-km-wide [16 miles] ribbon of gas flowing westwards at about 6 km/s [3.5 miles per second] compared to a speed of about 10 m/s [33 feet/s] either side of the ribbon."
The phenomenon called Steve had never been captured with those scientific tools before, even though it is "remarkably common," Donovan added. "It's thanks to ground-based observations, satellites, today's explosion of access to data and an army of citizen scientists joining forces to document it."
And going forward, data from Swarm and other scientific tools can begin to narrow down where this kind of aurora comes from. Crowdsourcing tools like Aurorasaurus use Twitter and submitted observations to track the aurora's appearance, and social networks of photographers, like Alberta Aurora Chasers, provide additional data that's crucial to tracking these features down more precisely than ever, Donovan said.
In the talk, Donovan concluded by pointing out that in 1997, scientists couldn't have pinpointed the newfound phenomenon at all. Fifteen years ago, it would have cost $200 or $300 million to track down something like Steve over the course of 10 years, he said. Now, with the help of citizen scientists and all the infrastructure that's available for observation, it was possible to close the loop in a matter of weeks, Donovan said.
"We really are in a truly new era," he added.