Never have I had the oppurtunity to see this natural wonder first hand. Simply put, I live to far south to see them. Thank you for the link, it is aways nice to see such as this for those of us who would not otherwise be able to witness these events. Most beautiful.
Yep, the Northern (and Southern) lights are what happens when earth's magnetic fields "funnel" high energy particles down to earth. These particles hit atoms in the upper atmosphere, and make their electrons jump to higher energy levels. When the electrons jump back down, they give off their extra energy in the form of light, which lucky observers see as the Aurorae.
It depends on the activity of the sun, as it is the source of the charged particles. Th ebest displays are when the Earth is in the path of a solar flare. I used to see tham quite regularly when I was a kid and lived in Northern Minnesota. They would look like curtains of light hanging in the sky.
