Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:
In 2014, photographer, citizen scientist, and weather enthusiast Chris Ratzlaff was out looking for the aurora borealis when he saw something weird in the sky. Something that looked like an aurora but could not possibly be an aurora.
For one thing, it was in the wrong part of the sky. It was too far south, well outside the auroral oval, the region encircling the pole where, on any given night, aurorae are predicted to occur.
And for another thing, this mysterious something was the wrong color. It was purple. Now I was a bit confused about this part at first, because I thought purple was one of the normal colors in an aurora (along with green). But aurora purple is more of a reddish or magenta-ish purple, whereas this new phenomenon was a true purple. A purplish purple, so to speak.
According to this interview with Canadian Geographic, Chris shared pictures of the whatever-it-was on a Facebook group called Alberta Aurora Chasers. Other members of the group then went out and got more photos. Hundreds of photos. And time-lapse sequences.
But still, nobody knew what this purple thing was. An early guess that it was something called a proton arc got shot down by an expert, at which point Chris wrote “[…] until we know what it is, let’s call it Steve.” This was a reference to the DreamWorks Animated film Over the Hedge.
In the film, a group of animals are confused and alarmed by the appearance of a neatly-trimmed hedge. One of the animals says, “I would be a lot less afraid of it if I just knew what it was called,” to which another animal replies, “Let’s call it Steve!”
This bit about being less afraid of a thing simply because you know its name is, in my view, a profoundly true statement about the power of language. But I digress.
According to this research paper from Science Advances, we now know, thanks to all those photos and time lapses from the ground, combined with satellite observations from orbit, what “Steve” is. Or at least we know that it’s associated with another phenomenon called an S.A.I.D. (SubAuroral Ion Drift). Thanks to Steve, we now have a new way to observe and study S.A.I.D.s and learn more about the interaction between the solar wind and Earth’s magnetic field.
As such, Steve has been assigned a more proper-sounding scientific name: Strong Thermal Emission Velocity Enhancement (or S.T.E.V.E. for short).