STEVE
Have you ever seen STEVE?
I’ve never seen STEVE, but I wish I could.
At TMAC Headquarters, it’s no secret we’re big fans of aurora borealis (or australis, we don’t discriminate). We’ve studied its causes, we’ve explored some of the biggest solar storms to ever hit Earth, and we’ve even followed them to other planets. Any time a strong batch of solar wind brings the possibility of a light show to the 40th parallel, we scurry outdoors in hopes of catching it, even if it’s only visible with our cameras.
For those of us without access to the extremes of north and south, any sight of the dancing night sky is a delight, but it’s easy to feel jealous of the people who get to see the aurorae in its prime, wondrous glory.
As we dive into scientific phenomena, we find they are rarely monolithic. The more time we spend looking at something, the more we see its intricacies and varieties. Lightning isn’t the only transient luminous event in our terrestrial sky. Sprites, elves, trolls, pixies, ghosts, and gnomes, among many others, light up our atmosphere. Eclipses are far from one-dimensional. You have your total solar, your rings of fire, lunar eclipses, and partials. And within those types are sub-phenomena that occur during the events.
The same is true of the aurora. It might make a lot of sense that something that seems to jump around the sky might present in multiple ways or manifest in slightly different mechanisms, but I never thought one of those ways would be named STEVE.
The incredible stripe in the photo above is a STEVE.
Though STEVEs are not new, until a group of aurora chasers and citizen scientists started noticing them in Canada in the 2010s, they were not studied or widely known to the public. Which is odd, because a STEVE is a massive auroral-like line; you would think we would notice something like that.
Since the science on STEVEs is nascent, we don’t quite have the mechanism pinned, but astronomers believe they have a good idea about what’s happening. The phenomenon is a ribbon of hot plasma, usually about 16 miles wide and 280 miles above the Earth. The plasma is hot – about 5,430 degrees Fahrenheit (3,000 C) – and flows faster than the surrounding plasma, making it something like a glowing plasma river.
STEVEs only appear when an aurora transpires but can occur in different locations. The bands tend to last between 20 minutes and an hour. They can stretch for thousands of miles, are usually aligned east-to-west, and can happen closer to the equator than the typical aurora.
OK, why STEVE?
When members of the Alberta Aurora Chasers first started bringing attention to the ribbons, they floated the name “proton arc.” However, this name would not do. Proton auroras are apparently a thing, but they are not visible, so these ribbons were not proton arcs. One of the chasers thought it might be funny to dub the phenomenon after the film Over the Hedge. In this animated classic that I have not seen, a hedge shows up overnight. To make this bizarre appearance seem less frightening, the characters decide to call it Steve. Since these ribbons had not really grabbed global attention before this point, they felt they had just shown up overnight.
Steve it was.
Usually, scientists want something a bit more formal, but they didn’t want to rock the auroral boat. So, scientist Robert Lysak developed a backronym: Strong Thermal Emission Velocity Enhancement.
STEVE was official.
After the proverbial light was shone on STEVE, scientific historians mined auroral researchers from the past and found STEVEs had been noted all along. In the photo above, we can see famed auroral scientist Carl Størmer had photographed and described STEVEs in the early parts of the 20th century. Potential observations as far back as 1705 exist, so STEVEs did not appear overnight like a hedge except in our consciousnesses.
After finally managing to see a tantalizing tidbit of aurora for the first time in 2024, I was so enthralled I knew I needed to go somewhere to see a major event. Now, I come to find I need to look not only for big storms but I also need to find a STEVE.
Further Reading and Exploration
Introducing Steve – a Newly Discovered Astronomical Phenomenon – Science Alert
New kind of aurora is not an aurora at all – Phys Org
NASA Needs Your Help to Find Steve and Here’s How – NASA
When Størmer Met STEVE – Aurorasaurus
When Swarm met Steve – European Space Agency
Rare Steve phenomenon and Northern Lights dazzle in UK skies – BBC
