|NATIONAL PARKS QUICKLINKS|
Backpacker Magazine – April 2008
The science behind the sky's natural fireworks display–and how to see it.
(3) The charged particles enter the atmosphere above the poles and collide with gas molecules to emit green, red, and blue light. "It's the same reaction that illuminates a neon light," explains Patricia Reiff, an astrophysicist at Rice University. The magnetic field guides the charged particles through the atmosphere 50 to 200 miles above the Earth, creating the aurora's distinctive curtainlike shape.
(4) Most aurora activity occurs in a band at 60-65 degrees north latitude–the approximate zone between Anchorage and Fairbanks. But above 45 degrees in the Midwest and Great Plains, people can often witness the displays. For campsites with good views, stay at the (A)Juniper Campground in North Dakota's Theodore Roosevelt National Park (North Unit), or (B) the Lake Jeanette Campground in the Boundary Waters Canoe Area Wilderness.
(5) The sun's 27-day rotation makes it possible to predict periods of strong aurora activity. A solar storm that generates northern lights on April 1 will likely cause more electromagnetic disturbances on April 28, when the same side of the sun faces the Earth again.