The Northern Lights

(Aurora borealis)

• The northern lights, or aurora, fill the night sky with mysterious lights of green and yellow and sometimes red.
• In the northern hemisphere, places that are closest to the North Pole such as Alaska, Norway, Scotland, and northern Russia experience the aurora on almost every clear night. The aurora is most active in these areas, which form a band around the pole. Fortunately for us, the band expands when there is a lot of aurora activity. The band will expand into parts of the northern United States such as Minnesota and Maine and on more rare occasions will even go as far south as Los Angeles.
• For people living in northern Minnesota the spectacular northern lights can be seen about every 2-4 clear, dark nights in 10.

What causes the northern lights?

• The northern lights are formed when solar winds enter into the Earth's magnetic field. The sun has a powerful magnetic field and is continuously emitting solar wind particles. The solar wind particles are electrically neutral charged particles that blast out from the sun at speeds between 1 million and 3 million kilometers per hour! Some of these particles get sucked up into the Earth's magnetic field and race along down towards the magnetic poles. When this happens the particles "excite" the gases in the Earth's atmosphere causing them to give off light.
• An example of excited atoms is found when clothes from the dryer get static cling. The static occurs when the electrons in the clothes shift from their centers and atoms from other clothing pick up the extra electrons. When the clothes are pulled apart the static makes a snap sound as the electrons snap back to where they were.
• In the atmosphere, after the electrons become excited they snap back to there normal positions and emit a light. When oxygen gas becomes excited, it gives off blasts of soft greenish light giving us the aurora.

• The aurora is actually present at both poles at every moment of the day and night. The southern lights are known as the aurora australis and they are actually mirror images of the northern lights.
• Auroras are best observed around midnight when the sky is at its darkest.

What do the aurora displays look like?

• The northern lights vary in form from rays that appear to wave in the sky to arcs that go across the horizon. Sometimes the aurora appears as a hazy veil across the horizon. The intensity of the lights depends on the amount of solar wind coming into the atmosphere. When there is a lot of solar wind the aurora expands into areas further south from the usual band around the pole.
• The aurora also produces an enormous amount of electricity. The electricity is formed when a good conductor (ionized solar wind) experiences a changing magnetic force. The aurora actually generates about 9 billion kilowatt hours of power a year; that is about ten times the amount of power that the United States uses in one year. It would be remarkable if scientists could somehow tap into this power supply for human use. It would solve some major environmental problems regarding current means of producing power.

There are many myths associated with the aurora from many different cultures.

• Since the northern lights are so mysterious it comes as no surprise that there are numerous beliefs on what they are and where they originate.
• The Inuit in Alaska described the aurora as the dancing souls of deer, whales, seals, and salmon.
• The Finns described the northern lights as foxes running with sparkling fur. They called the displays "fox fires."
• The Scots thought the lights looked like a group of merry dancers and the Swedes thought they resembled a polka dance.
• In Asia the Chuvash people thought the sky gave birth to a son when the lights rolled. They would look to the northern lights to help women having labor pains.
• The Inuit also thought the northern lights could heal diseases and many shamans looked to them for medical guidance.
• They also played an important role in religious ceremonies for some cultures. In the 1300s a Christian monk heard a voice saying that he should build a monastery. He looked out the window and saw the northern lights "pointing" to where the monastery should go. The monk followed the guide and built a successful monastery.

It is clear that the northern lights have had a profound effect on people living at northern latitudes. They also provide a pleasant splash of light during winter’s endless nights in these northern areas.

Sources

Savage, C. 1994. Aurora: The mysterious northern lights. Sierra Club Books, San Francisco.

Souza, D.M. 1994. Northern lights. Carolrhoda Books, Inc., Minneapolis.