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The Northern lights are poetry; they are nature's light show. The northern lights have filled people with wonder and inspired artists, but they have also frightened people to think that the end is near.
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The Latin name of the aurora of the northern hemisphere is "Aurora Borealis", which means "northern dawn. Originating in the atmosphere high above the surface of the earth, the northern lights can be seen during dark hours in the polar regions of the northern hemisphere. The sun's energy production fluctuates on an 11-year cycle, and maximum production coincides with high sunspot activity when processes on the sun's surface throw particles far out in space. These particles, called the solar wind, cause the northern lights.
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After 2-5 days' travel trough space, the plasma reaches the earth's magnetic field compressing it on the daylight side of the earth, and stretches it into a "tail" on the night side. This "tail", which forms a long cylinder, has a diameter equivalent to 30-60 times the earth's radius, and a length of up to 1000 times the same radius.
When these particles collide with atmospheric molecules, at 100-300 km (62-186 miles)
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altitude, some of the energy in these collisions transforms to visible light. The aurora occurs only above altitudes of 80 km (50 miles) and occasionally above 500 km (310miles). The average altitude is between 110 and 200 km (68 - 124 miles).
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Northern lights are most often seen in an oval- shaped zone around the magnetic north pole, an oval that lies above the coastal areas of northern Norway. The occurrence of aurora is varied even beneath the northern lights oval. It can be seen only against a dark sky, which must be clear, as the aurora originate far above clouds. The aurora is most frequent and intense from between 10:00 PM and midnight.
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Northern lights are more frequent in late autumn and early spring - October, February and March are the best months. In the northern parts of Norway northern lights can often be seen whenever the sky is dark and clear – in the southern parts, northern lights are seen about 2-3 times a month.
Altitude affects the color – strong, green light originates at altitudes of 120 to 180 km, red northern lights occur at even higher altitudes, while blue and violet occur mostly below 120 km (75 miles). Entirely red northern lights are sometimes seen, particularly at lower latitudes.
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Through different times and cultures and whenever they occur, different beliefs about the northern lights are found. The Inuit people around Hudson Bay believe the northern lights are on the outside of a dome, covering the earth. Through holes in this dome, the spirits of the dead can pass into the heaven believed to be on the outside. The spirits of the dead already in heaven creates the northern lights to guide the new arrivals. In the Middle Age, the northern lights were thought to be reflections of heavenly warriors; the soldiers that gave their lives for their king and country were allowed to battle on the skies forever, and the northern lights were the breath of these brave soldiers as they resumed their fight in the skies. The northern lights were also a sign of omen. They warned of illness, plague and death. When red, which is the most common color at low latitudes, they signaled the outbreak of war.
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In the northern parts of Norway people's conceptions were more characterized by awe for this mighty phenomenon. One should tread carefully and in no way should the northern lights be intimidated by waving, whistling, staring or any other form of defiance. In the Nordic book "The King's Mirror", written approximately year 1230, you can read several theories about the northern lights – their origin, cause and
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