The Aurora Borealis, Spirits Dance
The aurora borealis or the northern lights fascinate us and people have traveled thousands of miles just for a chance to see these brilliant light shows in the earth's atmosphere. However, even without the appearance of the northern lights our night skies are still magnificent!
The history lesson: Here in the northern latitudes, the effect is known as the aurora borealis (or the northern lights), named after the Roman goddess of dawn, Aurora, and the Greek name for the north wind, Boreas. The northern lights have had a number of names throughout history. The Cree call this phenomenon the Dance of the Spirits. In Europe, in the Middle Ages, the auroras were commonly believed to be a sign from God.
The science lesson: The auroras occur when electrons from solar winds interact with elements in the earth's atmosphere. These solar winds stream away from the sun and when they reach the earth, some 40 hours later they follow the lines of magnetic force generated by the earth's core. The colors of the aurora depends on which atom is struck and the altitude. Our Auroras are most often made up of green and yellow tones, although we have seen red and purple colors too.
- Green - oxygen, up to 150 miles in altitude
- Red - oxygen, above 150 miles in altitude
- Blue - nitrogen, up to 60 miles in altitude
- Purple/violet - nitrogen, above 60 miles in altitude
All of the magnetic and electrical forces react with one another in constantly shifting combinations. It's these shifts and flows that can be seen as the auroras "dance," moving along with the atmospheric currents.
The auroras generally occur along the "auroral ovals," which center on the magnetic poles, not the geographic poles. There are times when the lights are farther south, usually when there are a lot of sunspots. Sunspot activity follows an 11-year cycle and the last peak started in 2012. This solar maximum will last about four to five years meaning that there will be more auroras visible from locations south of the main auroral occurrence zone than during the solar minimum years. During the active part of the solar cycle, it is difficult to predict aurora beyond about two or three days. When sunspot activity maximizes in 2012-13.
The Coronal Hole: A gap that in the sun's atmosphere is call a coronal hole. When a hole forms a stream of solar wind spews into space. When this solar event occurs, Space Weather forecasters are able to forecast when this solar when will reach the earth in specific latitudes.
Viewing the Aurora in the Northern Summer
During the northern summer, sunlight prevents viewing the aurora at high northern latitudes. As the sun climbs in the sky until June 21st and then descends, the nights are too light to see the aurora. Because the magnetic pole is displaced toward North America, the auroral zone shown on our maps is at low enough latitudes to be seen even in the summer. Here are the rules of thumb for auroral viewing based on latitude.
- North of 70 degrees latitude aurora viewing very limited April15 through August 25.
- North of 65 degrees latitude, aurora viewing very limited May 1 through August 10. The auroral index should be 2 or more to see it south of this latitude.
- North of 60 degrees latitude, aurora viewing very limited May 15 through August 1. The auroral index should be 3 or more to see it south of this latitude.
- North of 55 degrees latitude, aurora viewing very limited June 10 through July 1. The auroral index should be 4 or more to see it south of this latitude.
- South of 55 degrees latitude, the aurora should be visible to observers in Canada and the northern US all summer if the auroral index is 4 or more.
Local artist Heidi Pinkerton, Root River Photography, has captured and created some of the best aurora images we have ever seen. I would encourage you to visit her online site and gallery. Heidi's aurora works were on display at the International Wolf Center in 2015.
Photographing the northern lights is challenging and takes patience. There is, of course, a nearly endless source of information online. A personal favorite online resource or digital guide was written by David Shaw at the Digital Photography School.
For Facebook users, another fun and interesting group to join or follow is Great Lakes Aurora Hunters ™. This group is for aurora enthusiasts and photographers in the Great Lakes areas who pursue the lights and they often share their experiences and photographic works on this page.
Even if the lights don't dance for you during your stay, the night skies over our dark woods and Bear Island Lake are breathtaking and inspiring.