Two Rare Non-Aurora Sky Glows Discovered: STEVE & Anti-STEVE

Two Rare Non-Aurora Sky Glows Discovered: STEVE & Anti-STEVE

The first of two new rare sky glow phenomena was videoed in 2017, over Southwest Canada. It appeared closer to the equator than where auroras normally occur, and was a different color……purple! Auroras are red, blue, and green. This first new sky glow was dubbed STEVE, for Strong Thermal Emission Velocity Enhancement. After deeper investigation and observation, it was determined that STEVE was a plasma stream of charged particles, or “sub-auroral ion drift,” a fast-flowing stream of gas at high temperatures. STEVE only flows West and before midnight. More information on STEVE can be found here.

In 2021, Norwegian Arctic researchers discovered another mysterious, non-aurora purple sky glow that flows East only after midnight. This similar but different phenomenon doesn’t have an official name yet, but in some ways, it is an anti-STEVE. European Space Agency (ESA) ’s Swarm satellites were able to measure the conditions in the purple part of the phenomenon before, during, and after it appeared. This showed that the ions were likely flowing eastward. More information on the anti-STEVE can be found here.


Image: Nanjo, S., Hofstra, G.A., Shiokawa, K. et al. Post-midnight purple arc and patches appeared on the high latitude part of the auroral oval: Dawnside counterpart of STEVE?. Earth Planets Space 76, 55 (2024).


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David Shiller
David Shiller is the Publisher of LightNOW, and President of Lighting Solution Development, a North American consulting firm providing business development services to advanced lighting manufacturers. The ALA awarded David the Pillar of the Industry Award. David has co-chaired ALA’s Engineering Committee since 2010. David established MaxLite’s OEM component sales into a multi-million dollar division. He invented GU24 lamps while leading ENERGY STAR lighting programs for the US EPA. David has been published in leading lighting publications, including LD+A, enLIGHTenment Magazine, LEDs Magazine, and more.


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