Northern Lights

One of my favorite memories is from when I was 9 or 10 years old. I was asleep in bed one August night when my father came in and woke me up. He had seen the northern lights in the sky as he walked the dog before going to bed. My sisters and I put on jackets and went out into the front yard to see this wonderful sight. When my own children were growing up, I was able to show them the northern lights several times.

Unless you are in the far north where true darkness doesn’t happen during the summer, the northern lights, or Aurora Borealis, may be visible any time of the year. They are caused when the earth is disturbed by the sun. Storms on the sun send out streams of particles into space. These take 2 or 3 days to reach the earth. As they approach the earth, they are pulled by the earth’s magnetic field towards the north and south poles. Here they collide with the gases of the earth’s atmosphere. These collisions give off light. If enough particles reach the earth, enough light may be produced to be seen as auroras. The larger the solar storm, the more spectacular the light display and the farther south it can be seen. Since the earth has a south magnetic pole, there are also southern lights, the Aurora Astralis, which may be visible in the southern hemisphere.

By using scientific instruments, it is possible to know when storms happen on the sun and to make predictions of when the northern lights are most likely to be seen. You can visit a website, Space Weather, to see a prediction of how likely it is that northern lights will be seen soon. Northern lights often show up 2 or 3 days after a major event on the sun - the bigger the event, the farther south they may be seen.

The sun goes through an 11 year cycle of activity. During this cycle, the number of sunspots increases and decreases. The last peak in the number of sunspots was in the year 2000. The peak in northern lights usually follows about one year later. We are now in the part of the sun’s cycle when there is a gradual decrease in sunspot activity but sunspots, and northern lights will still be seen, just less often.

Different peoples have had stories of what the northern lights are. See Legends and Myths of the Aurora for some information about the folklore of auroras.

So keep an eye on the sky whenever you are out at night. Look towards the north as this is where the northern lights usually show up. If you see flickering bands of light, most often in white or green, you may be seeing the Aurora Borealis. Good viewing requires clear skies and as little outside lighting as possible. There are some great photographs of the northern lights online, but remember, a camera will often pick up light that is not very noticeable to the human eye. What you see may not be quite as spectacular as the photos but it will still be a night you will not forget.

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