The Northern Lights
The Northern Lights are often referred to as the Auroras, and they occur as beautiful extraordinary displays of natural light in the sky. These can normally only be seen at night, and in what is known as the Polar Regions. In those regions, sometimes the lights are referred to as Polar Auroras, or the Aurora Borealis. The closer one gets to the North Magnetic Pole, the more vivid and beautiful the Northern Lights become.
While the northern lights usually appear high overhead when viewed from a location close to the magnetic north pole, as one moves further away from the north pole, this magnificent display of natural light tends to illuminate the horizon from one end to the other in a marvellous greenish glow. Having said that, there are times when the northern lights appear to be more of a red colour rather than green. When one considers the way in which these lights can appear to dance in the night sky is hardly surprising that some people view them as being almost eerie in a way, and this is perhaps why they have been referred to as a “dance of the spirits”.
So intrigued were people in the past regarding the northern lights, that even Benjamin Franklin theorized that they were the result of electrical charges being absorbed in the Polar Regions. He also suggested that the intensity of these displays were reliant on the presence of moisture in the air. Of course nowadays we know better, because rather than being the result of electrical charges being absorbed, they’re actually produced because of an interaction between solar winds and the earth’s magnetic field. When charged particles such as protons and electrons, collide with molecules and atoms in the upper atmosphere of the earth, usually above 50 miles, these displays of light take place.
These charged particles are known to originate from the sun. They arrive in the earths vicinity as a low-energy solar wind. It is then that the trapped magnetic field of that solar wind will orient itself southwards, and then connect with the magnetic field of the earth. Finally the solar particles will enter what is known as the magnetosphere and are accelerated toward earth.
When looking at the Northern Lights, it is the atomic oxygen, which causes the green tones, which are so characteristic. Furthermore, nitrogen ions and molecular nitrogen can also result in reddish and violet light, blue light, and even pink light, due to the interaction between the various gases and the earth’s upper atmosphere.
Sometimes the auroras appear as what could only be explained as curtains in the northern lights. These striations can of course change depending on an observer’s perspective and on occasions they can appear as a beautiful Corona. At this time auroral arcs can often be seen forming and moving towards the equator at around midnight.
It should be mentioned that the northern lights have also been seen from other parts of the world as well during the course of history. However, such sightings only take place at times when there has been an intense coronal mass ejection from the sun.
NASA has over the years has managed to record many wonderful Northern Light displays as they dance around the North Pole. Seeing these displays, as they were seen from outer space, can only be described as being, “amazingly beautiful”. In fact, the international space station has a huge number of photographs of this wonderful phenomenon.