I mentioned last episode that I was up in Alaska for some vacationing. It would be remiss of me to travel up to the Great White North and not mention the aurora borealis, a.k.a. the northern lights. Using a handy app (click here for more info), I checked for the lights every night of the journey. Unfortunately, they were either inactive, or they were active and it was cloudy out.
The only chance I actually did have to see them was on the plane ride up. They were really something. They looked like green S's stretched across the sky. But what are they really?
The aurora is caused by charged particles entering the atmosphere. This ionization gives off color, which then looks beautiful to those of us standing on the ground. Typical colors are red, purple, green, and blue. If the particles collide and ionize oxygen particles, the aurora is typically green or orangish-red. If the particles collide and ionize nitrogen, the aurora will glow blue or red.
So alright, we now know that the aurora is caused by charged particles, but where do they come from? Generally, from the Sun. Coronal Mass Ejections (CMEs) are these monster amounts of plasma that are ejected due to instabilities in the sun, and make their way to earth. Plasma has no shortage of ions, and solar winds blow the ions into our atmosphere. It usually happens somewhat predictably. Newspapers and now apps can tell you when there is a good forecast to catch the lights. Generally, they happen way up North, as far as America is concerned Northern Canada and Alaska. This is because the poles are pointed closest to the sun at various times of the year. Because the particles entering the atmosphere are charged, the lights ultimately try to align with the earth's magnetic field.
The word aurora borealis literally means northern lights. My research indicates that it is an amalgam of aurora from the Latin, meaning dawn, and borealis coming from the Greek meaning wind. I have also read that there exists a word borealis in Latin meaning northern. However, I will defer to NASA for the final word:
"In 1619 A.D., Galileo Galilei coined the term "aurora borealis" after Aurora, the Roman goddess of morning. He had the misconception that the auroras he saw were due to sunlight reflecting from the atmosphere." (Source here)
Question is: if there are northern lights, are there also southern lights? Answer: yes! The southern lights are referred to as aurora australis, meaning southern lights.
There is a region where the lights are on display. This is called an Auroral Oval. The location and size of this oval varies from night to night. Sometimes during geomagnetic storms, the oval will expand down to lower altitudes. I remember as a young child, maybe 5-7 years old, my father caught them out in Buffalo, NY, on a cold winter night. He called us outside and I had one of my first wondrous encounters with the strange physical world. My recollection is that they were red. It was immensely beautiful and the event was burned into my brain. I remember him saying that they usually happen way up north but sometimes we're able to see them down this low south. I've never seen them this low since. So, I was particularly excited when I realized I would be traveling right into their neck of the woods. Unfortunately I grabbed exactly 0 good pictures of them.
However, I did solicit a few pictures from an Alaskan Native I was visiting, to include for your enjoyment below. They are a marvelous phenomenon and a great example of the beauty possible in our universe.
