Steve

STEVE ("Strong Thermal Emission Velocity Enhancement") is an atmospheric optical phenomenon that appears as a purple and green light ribbon in the sky, named in late 2016 by aurora watchers from Alberta, Canada. According to analysis of satellite data from the European Space Agency's Swarm mission, the phenomenon is caused by a wide ribbon of hot plasma at an altitude of , with a temperature of and flowing at a speed of (compared to outside the ribbon). The phenomenon is not rare, but had not been investigated and described scientifically prior to that time. Discovery and naming The STEVE phenomenon has been observed by auroral photographers for decades. Some evidence suggests that STEVE observations may have been recorded as early as 1705. Notations resembling the phenomenon exist in some observations from 1911 to the 1950s by Carl Størmer. The first accurate determination of the nature of the phenomenon was not made, however, until after members of a Facebook group, Alberta Aurora Chasers, named it, attributed it to a proton aurora, and began calling it a "proton arc". When physics professor Eric Donovan from the University of Calgary saw their photographs and suspected that their determination was incorrect because proton auroras are not visible, he correlated the time and location of the phenomenon with Swarm satellite data and one of the Alberta Aurora Chaser photographers, Song Despins. She provided GPS coordinates from Vimy, Alberta, that helped Donovan link the data to identify the phenomenon. One of the aurora watchers, photographer Chris Ratzlaff, suggested using the name "Steve" for the phenomenon, deriving from a situation occurring in Over the Hedge, an animated comedy movie from 2006. The characters in the movie give the name to a hedge that appears overnight, in order to make it seem more benign. Reports of the heretofore undescribed and unusual "aurora" went viral as an example of citizen science on Aurorasaurus.