For night’s swift dragons cut the clouds full fast, And yonder shines Aurora’s harbinger; At whose approach ghosts, wandering here and there, Troop home to churchyards. -William Shakespeare A Midsummer Night’s Dream
Sure, we’re all familiar with the Polar Lights (unless you’ve been living under a rock, in which case you wouldn’t be reading this blog). I would like to take a deeper dive into what causes this phenomenon and some of the history behind it (mostly because I had a request from a friend, but also because it is a fascinating natural wonder of the world). Also, I’ve been in a terribly dreary mood and need to take a look at some of the beauty in our universe.
For those of you who don’t understand how the Northern Lights (or Southern if you wish to go there) work, here is a scientific explanation from a non-scientist. Hopefully this won’t bore you to tears, and if so, just remember there’s a little more to come afterwards. Let’s start with the basics: The center of the sun is 27 million degrees Farenheit/ 15 million degrees Celsius. As the temperature of the sun rises and falls, the sun bubbles and sends out plasma particles aka solar wind into space, taking about 40 hours to reach our dear planet Earth. The Earth is constantly being bombarded with radiation, debris, and magnetic waves, but lucky for us our magnetic field usually deflects any harmful particles/rays before they destroy life as we know it. Particles from the sun travel about 93 million miles, that’s 150 million kilometers toward Earth before being drawn to the Earth’s magnetic poles. They then pass through the shield, mingling with atoms and molecules such as oxygen, nitrogen, and other elements.
Now we know what causes the lights, but why are there so many different colors? It all has to do with the type of collision, the altitude, and the type of molecules. The typical colors displayed are green, yellow, violet, blue, pink, and sometimes white and orange. When particles collide with nitrogen, red is produced. When they collide with oxygen, we see yellow and green. Atomic nitrogen causes your blues and white molecular nitrogen would cause the purple hue. As far as altitude goes, green typically appears up to 150 miles (241 km), red above 150, blue above 60 miles, and violet/purple would be seen above 60 miles.
By the way, I’m a bit of a mind reader as well, so I know your next question is, “Where and when can we see this beautiful sight?!” Well, the most magnificent displays occur about every 11 years. The last peak was in 2013, putting the next at around 2024. That doesn’t mean it’s the only time you can view them, though. You can see this wonder on many a clear cold night. The best views for the Northern Lights are Sweden, Finland, Norway, Northern Canada, Alaska, and Iceland from September to April. During very active flares, you might even observe a bit from Northern England or the top of Scotland. For the Aurora Australis, the best views are in New Zealand, Australia, Antarctica, and in the very south of South America. We monitor these events for several reasons (other than the fact that they’re beautiful): they have the potential to knock out power grids, affect spacecraft in orbit, and we need to investigate how the sun’s solar activity affects our weather here on Earth.
As with any strange occurrence such as this, there have been many superstitions and recordings of the events throughout history. There are cave paintings in France that are speculated to date back 30,000 years. In 1616, Galileo used the name aurora borealis, taking the name of the Roman goddess of dawn Aurora, and the Greek name of the northern wind, Boreas. The event has been thought to be a harbinger of destruction and war and has been written about by the likes of Goethe, Halley, Aristotle, and Descartes. The Cree referred to the lights as “Dance of the Spirits” and in Medieval Europe they were believed to be a sign from God. In 1855 Norse mythology, the Valkyrior, who were warrior goddesses of Asgard that rode horses and were armed with spears and helmets, rode forth to carry on their errands with their armor shining a strange light which flashed up over the northern sky, hence creating the Northern Lights.
As for myself, I have yet to have witnessed this magical sight but am open to any free plane tickets that any of you might want to send my way. Best wishes!