The aurora is a visible manifestation of gasses being excited in the ionosphere. The process by which the auroras are visible works on the principles of magnetism and electricity. As highly charged particles from the Sun reach Earth, they collide with the ionosphere where Earth's magnetic field is located. When the particles hit the magnetic field, they give off light according to the gasses the charged particles collide with. The particles follow the magnetic waves within the magnetic fields and create the "curtains" or "waves" of the aurora. The height of the aurora starts around sixty miles and can be as high as two hundred miles. The colors of the aurora are created in a similar fashion to the way colors are created in plasma television sets.
Images of the Aurora Borealis:
Plasma is super heated or highly charged gas particles, the same as the aurora. Plasma in television sets is excited by electricity passing through it at high voltages, and then producing the desired color, according to the gas that is excited and the voltage applied. The only real difference is in the voltages used and size of the "picture." Colors in the aurora are produced, as mentioned above, according to the two main gases that are colliding with the charged particles and their altitude in the atmosphere. Nitrogen creates blue colors at less than sixty miles and violet at more than sixty miles.
To view the aurora in the US, the best city is Fairbanks, Alaska, as it is closest to the Arctic Circle. Eastern Canada also makes a great location to see the aurora, along with Iceland, Scandinavia, and Greenland. The Aurora are easier to view during the Spring and Fall Equinoxes as this provides the best ratio of dark nights and is not too cold; winters in Alaska can drop to negative forty degrees and the summer months have a small, if any, amount of darkness at night. The auroras are also more visible when there is heightened solar activity. The farther south a person travels, the less likely they are to see the aurora, but every few decades an increase in Solar activity, combined with a fluctuating magnetic field, will allow people as far south as Texas, and sometimes farther, to see the aurora.
Many viewers wish to photograph and videotape the aurora , and some more specialized equipment is needed to do so. For photographers, you will need a fast lens; the optimum lens would be a wide angle f/1.4 lens. The wide angle is needed to capture the full "bands" of the aurora, but is not completely necessary to photograph the aurora . Be sure to have a tripod for the camera to ease the process and set up a few breathtaking shots. The minimum lens specifications should be a 50mm f/2.8 or f/2.4 prime lens to have the best results. If using a digital camera, set the ISO settings to their highest point; this will allow for more of the auroral light to be captured on the digital medium. Also, keep shutter speeds as quick as possible, because some of the aurora's nuances can be lost to slower speeds.
Although there has never been any recorded sound from the aurora , it is difficult to dismiss the centuries of reports and claims that the aurora does produce sounds. Two main kinds of sounds have been reported; the first is a swishing or waving sound attributed to the movement of the aurora , and the other is a crackling sound similar to electricity. The "waving" sound can be attributed to human ears picking up the electrical impulses from the eyes. In very quiet environments, the ears will pick up the small disturbances of electrical information moving from the eye to the brain. This was tested after reading information on reports that said the sound went away after closing one's eyes. Research continues on the electric crackling sound but may be attributed to the strong magnetic fields.
The monument to the aurora has been talked about for many years and is located on the road out of the Fairbanks International airport. It is a geometric structure made from glass that is designed to reflect different wavelengths of light as visitors drive past. The idea is to give visitors a taste of what the aurora looks like as they are passing out of the airport.