Space Satellite Investigates New Aurora Light Phenomenon Called 'Steve'

Thanks to scientists, citizen scientists, ground-based imagers and ESA’s magnetic field Swarm mission, this purple streak of light in the night sky has been discovered. Originally thought to be a ‘proton arc’, this strange feature has been called Steve. While there is still a lot to learn about Steve, the electric field instrument carried on the Swarm mission has measured it. Flying through Steve, the temperature 300 km above Earth’s surface jumped by 3000°C and the data revealed a 25 km-wide ribbon of gas flowing westward at about 6 km/s compared to a speed of about 10 m/s either side of the ribbon. (Dave Markel Photography/ESA)

This purple streak of light in the night sky, originally thought to be a proton arc, was given the quirky name, “Steve,” by amateur stargazers. Flying through Steve 300 km above Earth’s surface, the European Space Agency’s SWARM satellite measured a temperature spike of 3000°C and revealed a 25 km-wide ribbon of gas flowing westward at about 6 km/s compared to a speed of about 10 m/s either side of the ribbon. (Dave Markel Photography/ESA)

Scientists have discovered a new feature of the northern and southern aurora light phenonema with the help of a group of stargazers posting photos online.

Eric Donovan, a University of Calgary professor, spotted the beam of light in photos shared by members of the Facebook group Alberta Aurora Chasers. Originally thought the to be a proton arc, the citizen scientists who observed the celestial phenomenon dubbed the strange purple ribbon “Steve” when they didn’t know what else to call the celestial phenomenon.

Donovan knew proton arcs aren’t visible, so he looked to data from a European Space Agency satellite called SWARM, which measures the Earth’s magnetic field. When it passed through “Steve,” the temperature jumped by thousands of degrees and the gas stream flowed at a different speed and direction than those around it.

Swarm is ESA’s first constellation of Earth observation satellites designed to measure the magnetic signals from Earth’s core, mantle, crust, oceans, ionosphere and magnetosphere, providing data that will allow scientists to study the complexities of our protective magnetic field. (ESA)

It turns out “Steve” is very common, but it just wasn’t observed before. SWARM will continue to provide insight into the ribbon of light going forth.

As for the informal name, it seems as though it’s stuck. BBC reports scientists have proposed “Sudden Thermal Emission from Velocity Enhancement” as a more scientific description that would make “Steve” a permanent acronym for the phenomenon.