A strong geomagnetic storm was brewing over Alberta (Canada) on September 27, when photographer Alan Dyer looked up into the sky and saw a purple light arc through the sky. It was a mysterious northern lights, known as “Steve”.
“Steve only appeared for 20 minutes, starting at 10:45 pm MDT, during the lull of the main radiance,” said Dyer, who captured the arc in 360 degrees.
Over the years, observers of the northern sky have reported that this luminous form sometimes occurs among ordinary auroras. It was often called the “proton arc” until the researchers stated that the protons have nothing to do with this phenomenon. Therefore, the members of the group Alberta Aurora Chasers gave an unusual radiance a new name: “Steve”.
“We seem to be ideally located in the Canadian Prairies to watch Steve, as we often see its arc during the northern lights just above or to the south,” Dyer notes.
The physics underlying the purple ribbon is completely incomprehensible. One of ESA’s space mission satellites, Swarm, flew straight through Steve during his previous appearance. The data showed a relatively hot gas river, about 25 km wide, rapidly flowing through the outer atmosphere of the Earth. “Steve” appears to be thermal emission from hot gas, not from flying electrons, “Dyer says.” But his origins and nature are still covered in mystery. “