Last month, while I was contemplating the auroras, I was thinking how strange they are. What they might have seemed like a thousand years ago, before science reduced them to interactions between charged particles. Shapeshifting greens and violets, huge in the northern sky.

Even with a basic grasp of their science, they still seem almost ghostlike. And that can be unsettling if you let it sink into your mind even a millimeter or two. Strange is a feeling European poets, painters and philosophers really started paying attention to around the 1700s. They noticed that the terrors inspired by dangerous mountains, waters and wildernesses weirdly contained a sense of beauty. The feeling that strangeness and fear could be aspects of beauty came to be called “the sublime.”

Science has explained a lot in the last 400 years, and scientists have spent much of that time insisting they’ll eventually have all the answers to everything. In the 1700s, one prominent scientist wrote that science had found out just about everything there was to know, with just a few scraps and details left to be logged and cataloged. Some still think this. But overall, it hasn’t turned out like that. The world keeps getting bigger, and weirder, and the sublime has not been scientifically explained.

When I was reading about auroras I came upon reports about a sky light whose science is still up in the air, as it were.

The unexplained light is named STEVE, for Strong Thermal Emission Velocity Enhancement. It appears aurora-like, but instead of spreading across the sky, it’s “an extremely narrow ribbon of vibrant purple and white hues,” as one report describes it. Sometimes, it’s accompanied by a line of small, colored blobs nicknamed the “picket fence.” STEVE tends to occur around the equinoxes, like auroras.

The long white line in this photo is STEVE (strong thermal emission velocity enhancement ) in British Columbia in May 2018. The green light at the right is an aurora. Photo by Robert Downie/Alberta Aurora Chasers

Except it’s not an aurora. As far as the astronomers can tell, STEVE and auroras arise through completely different mechanisms. Auroras are spawned when the solar wind encounters the Earth’s magnetic fields. STEVE seems to have nothing to do with particles from the sun. It may be a form of “airglow,” another inconclusively studied form of diffuse night sky light.

I think I’ve seen airglow, which in its own subtle way is as strange as an aurora. But one night, I saw something similar to STEVE, but stranger.

It was 10 or 15 years ago, late summer, early evening. Clear, black sky. The Milky Way bright over the spruce tops behind the house in Troy.

Running from just about due north, behind the house, to just about due south, over the trees, was a thin band of white light. You would almost call it pencil-thin, except there was no way to figure where it actually was. Was it at about cloud altitude, like a searchlight? But there were no clouds. Was it stratospheric, where jets fly? Or mesospheric, where auroras live? Deeper?

It was very thin, it ran the whole arc of the sky and it was completely motionless. I got my son, Jack, to look at it through binoculars. It appeared the same as it did by naked eye. We ruled out searchlight because it was so thin and still, fixed against the stars, no clouds, for at least 20 minutes. I went inside to unpack the 4.5-inch reflector telescope, but by the time I got back, the band of light was gone.

I described it to a couple of astronomers, but they had no clue. When I learned about STEVE this spring, I thought maybe this was my light. But photos of STEVE show bent, somewhat fuzzy, aurora-like lines, which tend to run east-west. My light was sharp, thin, straight and north-south.

It was strange. And true to the philosophies of the sublime, the anomaly of it was unsettling and beautiful, in its own weird way. So weird that I still feel unsettled by it years later.

No doubt there is some kind of scientific explanation for that band of light, just as there is some as-yet incomplete explanation for STEVE. There is also a scientific explanation, I’m betting, for flashes of light on the moon called transient lunar phenomena, which have been reported for centuries but no one knows what they are. There’s also, somewhere, somehow, an explanation for UFOs, which the military has finally, after decades of denying them, admitted exist (and to prove it renamed them UAP — Unidentified Aerial Phenomena).

Some of these things are very strange. There’s a chance conventional science — which, remember, at one time thought it had everything in nature nailed down until Einstein, the quantum physicists and space-based telescopes came along — there’s a good chance the explanations for some of these things are not going to have conventional explanations.

The sublime is one of those things. The feeling of stupendous awe, of fear and beauty, and strangeness, that arise when you watch the aurora.

Dana Wilde lives in Troy. You can contact him at dwilde.naturalist@gmail.com. His book “Winter” is available from North Country Press. Backyard Naturalist appears the second and fourth Thursdays each month.