Merry Dancers: Aurora Borealis

Owl Acres occupies about eight acres of Iowa land, and most of our exploration has been on that land, that dirt that we walk on. We’ve taken a few excursions into the vertical, wondering what’s going on beneath our feet, hidden in the vertical depths of the place. And now, let’s look up. The universe is out there, touching this place in its connections with the sun, the moon, the stars.

The sun has been giving us a particular treat recently. In the dark of night, when the sun is warming the other side of the earth, it has tantalized us with a display of color and magic that is usually reserved for the far north. The aurora borealis, or northern lights, doesn’t usually dance in Iowa skies. This year, though, we got periodic alerts that if we were lucky, we might see them.

One such alert last spring caused Bryan to wait up until the sky got as dark as it gets here with the light pollution, and watched for the lights. What he saw was little more than a blur, a suggestion of light near the horizon. Definitely not that rippling curtain of green with red and purple streaks that people talk about. He reported seeing nothing. The next night, he saw the same smudge of light on the horizon. This time, he tried taking a picture with my iPhone camera and voila! There they were just as promised. He still couldn’t see them without the camera though. The reason it seems is this. When you look at something, you are seeing it in the instant. The camera, however, can be set to gather light over a period of time, so if you don’t move it, it will continue to gather the light to enhance the image. Add Apple’s sophisticated processing software, and you can get a picture of something you cannot see by yourself.

In early October we heard once again that we might see the northern lights. Bryan grabbed my iPhone and got some nice pictures of it early in the evening. In spite of staying up for a couple more hours, with a clear sky to boot, there were no more lights. The show was over.

If we had been in Alaska we certainly would not have needed the camera to show us what we were seeing. Neither, of course, did the people who live at the top of the world. What they saw though was not electrons exciting oxygen and nitrogen molecules at the limits of outer space. They saw myths and legends come to life in the night sky.  Ancient Norsemen saw Odin’s fallen warriors crossing the glowing, pulsing bridge to Valhalla, sometimes guided by the Valkyries. In Finland, giant firefoxes race across the heavens, lighting off sparks when their tails touch the earth.

The Sami people saw the souls of the dead who could grab you and carry you off if you got their attention, so the lights were to be avoided.

Scottish people called them “merry dancers” and thought of them as fallen angels or sky warriors engaged in epic battle. North American peoples saw the souls of their ancestors, some with torch-bearing spirits who led them across the abyss to the land of brightness and plenty. Some heard the lights whistling, communicating between the dead and the living. Omens of death, war and destruction also flowed out of the aurora borealis. Lots of red color in the display portended bloodshed and disaster. And yet, others saw the lights as the reflection of a cozy fire maintained by the gods to remind their people of their protection and love. Some people thought the lights meant good fishing. Others saw celestial athletes playing a ballgame with human skulls. Others saw them as sleighs taking people to a fancy party. Whatever the interpretation, the Northern Lights have had a profound effect on the people who see them.

But what exactly is going on up there? The scientific explanation goes something like this.

The sun is a huge nuclear furnace. Explosions continuously occur on the sun, spewing masses of charged material out into the solar system. The amount of matter the sun ejects varies throughout an eleven-year cycle. The year 2024 is at the top of the cycle, called the solar maximum. Events called solar flares and coronal mass ejections at the surface of the sun are bigger at this point in the cycle, sending more than usual material racing across the 93 million miles from the sun to the earth. When this material, in the form of charged electrons, reaches the earth, it hits the earth’s magnetic field. This magnetic field, called the magnetosphere, is created by the earth’s iron core. It surrounds the earth, protecting us from a lot of the radiation from the sun. The magnetosphere is strongest at the poles, so when the electrons hit it, they are funneled into areas called auroral ovals, one at the north pole and one at the south pole. Here they collide with molecules of nitrogen and oxygen in earth’s upper atmosphere, exciting those molecules. The oxygen and nitrogen molecules don’t stay in the excited state, though. They calm down and release the extra energy in the form of photons—light. That light is what creates the aurora borealis at the north pole and the aurora Australis at the south pole. In most years, the activity is concentrated at the polar regions between 60 and 75 degrees latitude, but in peak years like 2024, there’s enough energy to send them southward along the magnetic lines.

Now wouldn’t you rather think of them as cosmic messengers than as plain old electrons?

Feature Photo by Author. Alt text: The Aurora Borealis over Iowa in May. The sky is all green and purple light, shot through with vertical shafts, the whole hanging over black silhouettes of trees, yard lights and the horizon of Owl Acres at night.

In line photo of the Aurora over Iowa in October. View looking north, this one has lots of red. Photo by Author.