What Are The Northern Lights?

Aurora Borealis.  What are these lights that grace the northern sky?  Lights that draw people from all over the world to experience?  There is a growing tour industry based on the Northern Lights. Japanese visitors flock to the Interior of Alaska to watch this night time phenomenon. The official start of the Japanese Tour Season is Dec 26 and tours continue through til the end of March.

One of the questions always asked by visitors at any time of year is - "What time do the Northern Lights come on?" As many times as the question is asked, there have been a whole number of misinformed answers.

I use to hear people tell visitors that the best time to see the lights was from 2 a.m. to 4 a.m. Many was the time I heard passengers relate that that was the information they had received upon asking and they set an alarm to get up at that hour and see the lights and they had not been out. The lights had been horizon to horizon starting about 10 p.m. until nearly 1 when they faded away. Another fellow flew to Fairbanks specifically to see the lights - he too was up till about 4 when he gave up and curled up on a seat at the airport waiting for the first flight out. While he slept, the lights played across the heavens beginning about 6 a.m. and continued for an hour.

So then, the next question is - What exactly are the Northern Nights? There are volumes of technical information relating the exact scientific causes for this light show. Most people have neither the time nor inclination to wind their minds around the intricacies of the lengthy drawn out explanations. In today's world - make it simple and easy to understand.

After reading and scanning through some of these volumes I came up with a fairly simple explanation that gives the most rudimentary basis for understanding it. The sun is a huge ball of exploding gases with it's own magnetic field. Magnetically charged gasses are continually flung into space from the burning exploding sun. This mass of moving gasses propelled by the force of solar explosions is called the solar wind. The earth's magnetosphere extends far out into space acting as a protective buffer, keeping most of this solar material from entering the atmosphere. This allows the solar wind to flow around the earth in much the same manner as water flows around a rock in a stream. Although it does a commendable job of saving our lives from this lethal onslaught from the sun, there are some gasses that do actually penetrate the protective cloak that surrounds us.

These magnetically charged particles of gas from the sun now inter-react with the gasses in our own atmosphere. It is this reaction which causes color. Reaction of oxygen molecules 100 miles above the surface of the earth creates the rare red aurora. Oxygen reaction between 62 and 180 miles creates the more common yellow to green light most frequently seen. Nitrogen reaction at 62 miles creates the fringe of red sometimes seen with Auroras in contrast to the all red from higher oxygen. Hydrogen and helium at high altitude creates a blue and purple which are not often visible to the human eye.

Movement - what creates that graceful dance of lights in the northern sky? Again it is reaction - this time from the magnetic fields. The particles of gas from the sun are charged with the sun's magnetic field and when they approach particles charged from the earth's field there is attraction and repulsion - movement of light as the mass follows the flowing path of the earth's magnetic field. Because of this, the lights are seen at the poles where the fields converge.

There is no set time for these processes to occur - it is continual - 365 days a year - 24 hours a day. But it is only visible during hours of darkness - which in Alaska's interior is anywhere from the first week in August to the first week in April. They play in the clear chilly nights of first frost in August, in clear bitter frigid nights when the temperature plunges from zero to 70 below without wind chill through December, January, February and into March.

Science has advanced to the point where monitoring of activity on the sun can now give a good indication of when conditions will prevail to create the light show here on earth. Precise enough to the day, the hour and the intensity of the display.

The University of Alaska has facilities dedicated to the study of the aurora borealis. Japanese funding has contributed to some of this complex. In the early 60's, the University purchased land approximately 28 miles north of Fairbanks and built Poker Flats Research Range - a rocket launching facility to send barium rockets into the atmosphere to create artificial auroras in order to study and better understand the phenomenon. Observation domes have been built on surrounding hill tops to capture and record information. A thoroughly fascinating science. The museum at the University includes a detailed explanation of the Aurora for visitors as well as captivating film footage of the lights in action.

The lights seen over southern skies - Antarctic regions - are a mirror image of those seen in the northern skies.

Fairbanks. Alaska is fortunately located in a position to be one of the two best places on earth from which to view the lights. Because of the close proximity to Japan, this location favored their tour development. Aurora watching is what it is all about.