Appearances can be Deceiving, Part II

Last night we were hibernating. Rosie’s friend K was over and they were baking cookies. I was trying to stay out of the way while still having a good time. At 8:45 someone, we think it was our friend Wrench, made a very garbled cell phone call to us telling us that you could see the northern lights right then.

We live in the very middle of the Twin Cities. It is not the kind of place one associates with seeing the aurora borealis. One time last year, they were visible all over the city and it blew me (and a lot of people) away. I’d only seen them at this latitude one other time and that had been by the river in Stillwater, a much darker night sky.

Anyhow, the three of us stepped out on the balcony last night and sure enough, strange bands of light speared the orange night sky, mostly in the west and north. I snapped some photos, with mediocre results.

They were strange northern lights, but when aren’t they? It didn’t seem likely on this hazy night, but what else could it be?

As usual, you should never just dismiss questions like that. With a little bit of poking around, it turns out that what appeared in the Minnesota sky last night was not the aurora borealis, but “light pillars.” They’re cousins of such phenomena as sun dogs.

Pillars appear in the sky when snow or ice crystals reflect light forward from a strong source such as the sun or moon. Those crystals with plate or column shapes provide an excellent surface from which the light may reflect toward the viewer’s eyes. Ice crystals in the form of plates or columns can be found in ice clouds (cirrus or alto forms), ice fogs, snow virga falling from high-based clouds, blowing snow and diamond dust.

Because the light rays forming pillars are reflected, they take on the colour of the incident light. For example, when the sun is higher in the sky, pillars are white or bright yellow in colour. But when it is near the horizon and its light colour dominantly orange, gold or red, so is the resulting pillar.

Last night’s lights were most likely actually caused by the redirection of streetlights or other bright lights in the city. Surreal that the city can create an appearance like that, mimicking and competing with brilliant natural occurences.

The coolest thing in my rudimentary understanding of light pillars is that they form when long and skinny ice crystals are falling so slowly through a very still atmosphere that they all align so that they are parallel to the earth. Thinking about it, I derive a strange, calm sense of mysterious order.

7 thoughts on “Appearances can be Deceiving, Part II

  1. Terry

    I step out into the back yard most nights to look for the northern lights and to check out the stars & planets (Mars has been fun to watch this year) – Alas I did not see the ice pillars and subsequently feel a little jealous.

    Living in the city it is especially important to keep in touch with that part of ourselves that appreciates the world around us – It’s too easy to lose touch with it when we are always keeping under ceilings and car roofs.

    I’m envious of Deb over at Sand Creek who can step outside and look at the night sky without half the sky washed out by the city light.

    Your posts like this and the hummingbird moth post from last summer are the kind I enjoy the most – As well as your snapshots from various canoeing and hiking excursions.

    Thanks for sharing and keep up the good work!

  2. Deb

    At first when I saw the picture I thought “how could I miss the northern lights if they were even visible in the cities!” Then I read your explanation. It is nice that you (and Wrench) have the eyes to appreciate phenomena such as this.

    Yes, it is nice to be able to see the night sky, although on cloudy nights I can see the lights of Duluth to the northeast. Last night in the moonless sky I saw literally “clouds” of stars, infinite points of light. I think I saw northern lights too but they weren’t very brilliant. I remember that spectacular night last year.

  3. kate

    The sky is doing amazing and crazy things lately. On my way to work this morning, the fog and a cloud bank over the Mississippi river caught the rising sunlight and made a rainbow. At 830 in the morning on a Monday, I got to see a rainbow! What a neat way to start my morning (before the gridlock of traffic slowed me down).

    Great post, bum, and that photo turned out pretty well considering…

  4. the dharma bum Post author

    kate – i saw that too this morning. i don’t think that wasn’t your traditional rainbow, i’m pretty sure those were sun dogs. very closely related to what we saw saturday night. i believe the light pillars were caused by ice crystal redirecting light from street lamps. this morning it was light redirected from the sun.

    the one to the east of the sun wasn’t as bright as the one to the west, at least from my perspective, but it was there. a neat symmetry. i believe it was responsible for at least one accident on my way to work… someone rear-ended someone else on the i-35e bridge over the mississippi and i don’t doubt it was because they were distracted by the sundog. i can only think so because my commute is usually accident free and there were two total accidents i saw.

    i saw these a couple times on my way to work last winter. it’s neat because you only see them on the really cold, clear mornings. your commute just switched from going north in the morning (with the sun behind you) to south and west, so these might not be the last ones you see this season…

    i ramble…

  5. kate

    Sun dogs! Or as the dyslexic in me typed, “Sun gods!” Now I know what they are, thanks! That probably also explains the congestion I experienced before the usual spots. Is the nearing apocolypse to blame for the increasing number of events in the sky? Or are we just lucky?

  6. the dharma bum Post author

    Saw them again this morning. Even bigger and brighter… Didn’t seem to cause any accidents on the freeway this time. This morning was really neat… Everything was very still, but there was almost a fog of ice everywhere, too. Made the whole world look frozen.

Comments are closed.