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The Northern Lights "Nature's Own Special Effects"
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".
Interestingly, even Benjamin Franklin at one point had his own theory as to what caused the Northern Lights to appear. Franklin suggested that it was due to the absorption of electrical charges taking place in the Polar Regions and that when large amounts of moisture were present, the light intensified. Of course we have a better understanding of this phenomenon nowadays, in that we know they're due to an interaction between the earth's magnetic field and the solar winds. In fact, the Northern Lights are produced when charged particles such as the electrons collide with molecules and atoms in the earth's atmosphere, usually at an altitude above 50 miles.
Conclusive evidence shows that these particles originate from the sun and that they arrive here in the earth's vicinity as low energy solar winds. When this happens, these particles become trapped within the magnetic field of the solar wind itself. This then ends up connecting to the Earth's magnetic field before eventually entering into the magnetosphere, where they are then propelled towards the 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.
At different times in history, the Northern Lights were capable of being seen in other places in the world, making headlines in newspapers all over the world. This was due to exceptionally intense and concentrated coronal mass ejections from the sun.
NASA has accumulated a wealth of photographs of this magnificent phenomenon. As you can imagine, while it may be beautiful to see from here on earth, when seen from outer space, the display is even more spectacular.
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