The Science Behind the Enthralling Northern Lights

September 16, 2016
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Absolutely beautiful photographs of the northern lights hanging over mountains and rivers have spread across the Internet, fascinating and dumbfounding their viewers. In art and literature as well, the northern lights have always been depicted above expansive lands empty of people, buildings, or any other signs of human civilization. Upon visiting Alaska and several of its cities via cruise ship, I never imagined that I would be able to observe such the northern lights, which are the epitome of Alaska’s rich and unadulterated scenery. After all, they only appear in areas with little to no city lights or air pollution, and even then they do not come out daily and are hard to see with the bare eye. When I heard the announcement that the northern lights could be seen from the deck of our cruise ship I was astonished, and my astonishment only increased after going out and seeing them.

I had been told by a tour guide a few days before this occurred that the northern lights were definitely not easy to see with the bare eye, and that often times a camera with the correct exposure can capture much more of the northern lights that we can see. Thus, I didn’t expect to see the lights so clearly and vividly above me, and I was astounded. The diagonal rays of light were varying shades of green and bluish-green, and their arrangement often shifted. I could not even fathom how the lights could change patterns themselves, and part of me believed that my mind was creating the movement. The lights usually dimmed after several minutes, but the rare times in which the lights would burst into a vibrant green were the moments I will remember the most.

After observing the northern lights, I felt truly enlightened by the lights’ beauty, and yet I had no remote idea as to what the lights were scientifically, how or why they appeared there, why they were that color, and why they would glimmer before my eyes. When I returned to my house, I also returned to the comforts of the city, including free access to the beloved Internet. In my research, I discovered that the aurora borealis (northern lights) and aurora australis (southern lights) occur when highly charged electrons from 1 million miles per hour solar winds interact with elements in the earth's atmosphere, producing a beautiful light show in the earth’s atmosphere. More specifically, the electrons from the solar winds reach the earth after approximately 40 hours, and then they adhere to the lines of magnetic force generated by the earth's core and travel through the magnetosphere, a teardrop-shaped area of highly charged electrical and magnetic fields. After passing through this area, which contains highly charged electric and magnetic fields, the electrons from the solar winds then react with atoms of oxygen and nitrogen at altitudes from 20 (lower atmosphere) to 200 (upper atmosphere) miles above the earth's surface. In this reaction, the atoms’ electrons move to a higher energy state, and when they return to their lower energy state they release a photon. Based on which atoms the electrons encounter and the altitude of the encounter, different colors are made, including bright but cool blues and greens, vibrant reds and yellows, and vivid purples. The northern lights that I observed were green and blue, meaning that the electrons from the solar winds were interacting with excited oxygen and ionized nitrogen around the middle of the earth’s atmosphere. Additionally, these auroras often appear as “curtains” of lights, but they can also be arcs or circles, as they follow the  lines of force in Earth’s magnetic field.

Although the scientific reasons behind the enthralling northern and southern lights are accessible today, in ancient times, many creative beliefs surrounding this phenomenon existed. Some Inuit believed that the spirits of their ancestors could be seen dancing within the glimmering auroras. And in Norse myths, the auroras were a fiery bridge for the people to reach the gods. But to me, the northern lights were simply stunning, even though I was not aware of the science behind it, nor did I believe it was a stage for dancing ghosts or a bridge to above. To me, it was a reminder that humans have not possessed and adulterated everything in this finite world, and that oftentimes, the most beautiful sensations come naturally.

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