A bunch of citizen scientists and aurora photographers in Canada have discovered an atmospheric phenomenon that scientists know little about. The aurora enthusiasts have named it Steve. It has garnered the attention of researchers at the European Space Agency (ESA), NASA, and other institutions. The citizen scientists initially thought it was a proton arc, but proton auroras are not visible to the naked eye.
Swarm data sheds some light on Steve
This new type of light in the night sky was first documented by aurora photographers in the Facebook group Alberta Aurora Chasers last year. Eric Donovan, a professor at the University of Calgary’s Department of Physics and Astronomy, found the photos in the Facebook group and took an interest in the phenomenon. Since the first observation last year, there have been dozens of observer reports.
Professor Donovan was unable to recognize the light in the pictures as a categorized phenomenon. So, he and his colleagues used the ESA’s Swarm magnetic field mission to learn about it. Swarm is a group of satellites that take measurements of the direction, strength, and changes in the Earth’s magnetic field that trigger auroras. Auroras stem from the interaction of the electrically-charged solar particles with the Earth’s magnetic field.
Interestingly, one of the Swarm satellites flew right through the atmospheric phenomenon recently. Data from the satellite revealed that it was a hot stream of rapidly flowing gas about 300 kilometers above the Earth’s surface. The ESA said in a statement that the temperature in an area 300 kilometers above the Earth surface jumped by a staggering 3,000 degrees Celsius (not a typo) inside the gas stream than outside it.
Also, the 25-kilometer gas ribbon was flowing at 6km/s (13,000 mph), about 600 times faster than the air on either side of it (10m/s). Professor Donovan said the phenomenon appears quite frequently, though we never noticed it until recently. The discovery was made possible by an army of citizen scientists, ground-based observations, satellites, and an explosion of access to data.
The 25km gas ribbon aligns east-west, extending for hundreds of kilometers. Donovan said the phenomenon appears to be seasonal. It disappears between October and February. It gives off the light in purple and green colors. Scientists are still not sure what causes it. Donovan said he had been working on the specific conditions under which it occurs. He plans to publish the details shortly.
The story behind the name ‘Steve’
Steve is just a placeholder rather than official scientific name. The citizen scientists were inspired by the 2006 children’s movie Over the Hedge, where characters would give the name Steve to things they had not seen before. However, some enthusiasts have tried to turn the name into an acronym. Chris Ratzlaff proposed “Sudden Thermal Emission from Velocity Enhancement (STEVE)” in the Alberta Aurora Chasers Facebook group. The description is based on primary satellite observations.