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The Aurora Borealis, or Northern Lights
An Ojibwa Legend
Many of us who live in the Northern areas of the American Continent have had the delightful experience of watching the magnificent display of moving multi-coloured, misty lights, as they flash across the night skies.
A number of theories and explanations have been advanced for this natural phenomenon known as the "Aurora Borealis" or "Northern lights", but let us travel in our minds, back through the eons of time and discover how they really came into being. We are in a world that spins in a perfect vertical position upon its axis. The moderate temperature is about the same all over its surface and beautiful vegetation is everywhere.
As we return through time, we witness the great Flood where everything becomes submerged and finally lost. As the waters gradually recede their tremendous weight throws our planet off its balance and it now tilts to one side, thus causing long dark periods in the North and South.
Not quite all is lost however, for in the North lived a simple and God-fearing race of people, known to us now as the "Mongols", whom the Great Manitou (their name for God) had spared from this great deluge.
When they could no longer see the Sun and feel its warmth, fear came upon them and they prayed to the Great Manitou to save them. In his compassion, the Great Spirit decided to take them to the warm and fertile plains of this Continent and he bade them gather together their families and 'what goods they could carry and trek across the barren North to the "New Land".
Because there was no daylight many became lost and perished within the deep crevices caused by the flood waters.
Again they prayed for help and the Great Manitou devised a plan. Covering the Northern cap of the world with great crystals of ice, some as high as mountains, he was able to capture the rays of the hidden sun and reflect them up into the sky, thus providing light for his people to see by. Onward these stalwart people trekked, and became the forerunners of our many Indian tribes.
The great ice prisms split the sun's rays into all the beautiful colors of the spectrum and because of this, people for thousands of years have witnessed this wonderful miracle, the Northern Lights!
What I've seen
Living in Alaska for 37 years allowed me plenty of opportunities to observe the Northern Lights, or Aurora Borealis, and I have to admit that they are as amazing as people imagine. I lived in Anchorage, Fairbanks, and Valdez, and saw them all three places. I have spent many an evening standing in the driveway at -50F in a bathrobe and slippers, watching them swirl above me. Once I made the mistake of running back inside to put on some warm clothes, only to find when I returned that the show was over! So I made it a habit to just shiver and enjoy it!
Actually, some of the best Auroral displays I saw were during August, when it was just starting to get dark. But the ones with the best variety of colors seemed to always occur in the deep winter, when the Northern Hemisphere nights are longest.
Most of the auroras I have seen have been green with white edges, tinged in red. I have never heard them make noise, although there are many reports of that happening.
What causes Northern Lights?
I drove tour buses in Fairbanks, Alaska for a number of years. Probably the funniest question I ever got was “where do I get a ticket for the Northern Lights?” But one of the most common questions I used to get was what causes Northern Lights, so I tried to work an explanation into my tour right from the beginning.
Northern Lights are caused by geomagnetic storms in the outer sections of the Earth’s atmosphere. The lights happen when electrically charged particles from the sun collide with gaseous particles in the earth's atmosphere. Storms on the surface of the sun send gusts of charged electrons and protons toward the earth on the solar wind. Most of these charged particles are deflected by the earth's magnetic field, but some make it through the earth's atmosphere, particularly at the northern and southern poles where the magnetic field is weaker. Once the particles enter the earth's atmosphere they collide with gas particles and emit the light that we see as the aurora. The charged particles strike atoms and molecules in the Earth's atmosphere and excite those atoms, causing them to light up.
Variations in color are due to the type of gases that are colliding. The most common color, green, is caused by oxygen molecules about 60 miles above earth. Rare, all-red auroras, are produced by high-altitude oxygen, at a height of up to 200 miles. Nitrogen causes a blue or purplish-red color. Northern Lights generally occur from 50 miles to as much as 400 miles above the earth's surface.
What happens in an aurora is similar to what happens in a neon light. In a neon light electricity is used to excite the electrons in the gas atoms inside the glass tube. When the electrons are excited they emit photons of light as they discharge that extra energy.
Electricity in the Northern Lights
The solar wind can generate billions of watts of electricity in an auroral display. Satellites have measured this electrical power at a range of 400 to 900 billion watts for the northern hemisphere. This is more than the U.S. uses in a year! Unfortunately there is currently no way to capture that energy and use it, mainly because it is spread out over such a vast area.
Northern Lights can interfere with electric and navigational systems, and actually damage the electrical power grid and satellites operating in space. This is why scientists are trying to understand them. In 1859 there was a power surge from a major geomagnetic storm and a solar eruption that hit telegraph offices around the world. Some telegraph operators got electric shocks. Papers caught fire. And many of the telegraph systems continued to send and receive signals even after the operators disconnected their batteries, as though the electrical current was in the air itself. Brilliant auroras accompanied this event, visible as far south as the Caribbean.
Poker Flat Research Range 30 miles outside Fairbanks, Alaska, is the largest land-based rocket research range in the world, and is operated by the University of Alaska's Geophysical Institute. They study the arctic atmosphere and the Northern Lights.
As noted in the story about the 1859 storm, space weather can cause serious damage on earth, so it is important to be able to forecast these events to help avoid damage. A 2008 report from the National Research Council estimates that a storm of similar magnitude today could cause $1 to $2 trillion in damage globally. In order to avoid such damage, actions such as switching satellites to standby mode and rerouting airplanes away from polar routes can be taken.
Once upon a time I was offered a job in the launch control station at Poker Flats, and for some reason I didn't accept it. I kick myself over that now, because it would have been a totally unique experience. Plus, at that time 35 years ago I would have been the only female rocket launcher in the nation!
When I was driving buses in Fairbanks I was once doing a city tour and having a coffee break while my people were enjoying the museum. In the cafeteria I happened to share a table with an astronomer from the University of Alaska Geophysical Institute, who studies the Northern Lights. He told me all kinds of fascinating stories about the aurora, but the thing I remember most was his explanation of the amount of energy contained in an aurora. I remember saying “so you’re telling me that the amount of energy in a good auroral display would be enough to power the United States for a YEAR?” He replied, “No. I’m telling you that the amount of energy in an AVERAGE aurora would power the U.S. for a year.” WOW!
What is the best time of year to see Northern Lights?
The Northern Lights are most visible in autumn and winter, when the Northern Hemisphere’s nights are at their longest.
Auroras do occur year round but in the far north most of the summer months are not dark enough to see them.
Best places to view the Northern Lights
Since the magnetic fields are weaker at the poles, Northern Lights (or Southern Lights in the southern hemisphere) are most visible in the far north, such as Alaska or Greenland.
Sometimes the aurora can be seen as far south as the northern contiguous United States, but this is not common. Alaska is a common destination for U.S. Northern Lights observers. Around the world Scandinavia and Greenland draw a lot of observers because of the consistently clear skies and the brightness of the lights.
You don't have to leave town to view them, but you do need to get away from city lights to see them at their brightest.