Northern Lights
The aurora borealis or northern lights is a name referring to the lights that take place in the northern hemisphere. However, there are also lights that take place in the southern hemisphere and are called the aurora australis or the southern lights. In Alaska, the northern lights (aurora borealis) are one of the most unique features of the state. Alaska is found to be one of the best places to experience these marvelous and rare displays. Many still wonder the creation of this natural phenomenon but much has been explained by recent scientific technology. The creation of the lights start with the sun and the activity it produces. The sun is constantly throwing out particles into space. These particles, often referred to as solar wind, is thrown toward the earth. This wind produced by the sun is a super hot stream of plasma made up of electrons and protons. As the violent wind approaches the earth, much of it is shielded off by the protection cover of the earth's magnetic field. As it hits the earth, the magnetic field guides the plasma towards the northern and southern poles where the particles can enter. As the solar particles enter the earth's atmosphere, they slam into the gas particles in the air. As they collide with each other, they create a glowing effect of different colors.
As these lights are created by the solar wind thrown from the sun, they create oval rings around the north magnetic poles. The stronger the particles and wind thrown from the sun, the larger the oval is. Therefore, if there isn't much solar activity, the oval is thin and far to the north. However, during large solar storms, the oval is thick and moves farther south.
In the case where the wind is very strong, the oval can sometimes stretch across the southern United States and Europe. For a given level of solar activity, the thinnest part of the auroral oval is always on the sunny side of the earth, while the thickest part of the oval is over the nighttime side of the earth. The bulge of the oval is on the night side of earth. As a result, it is more likely to see the aurora after midnight. If you live near the northern auroral oval, you will often see the lights on most clear and dark nights. However if you do not live near the occurrence of the oval, the lights can only be seen when there is enough solar activity to stretch the oval down to lower latitudes. Often people that live in the southern U.S, Mexico, southern Europe, and surrounding areas may experience the lights once in a life-time. However for those resident of Alaska and surrounding areas the best time to watch for the aurora is late at night or in the early morning hours, from about 10 PM to 3 AM.Another remarkable thing about the northern lights is the dancing effect that they create in the sky. As the wind is thrown thousands of kilometers out into space where it later collides with the earth's magnetic field, it will produce a powerful force while buffeting and distorting the shape of the earth's field. The gusts of the solar wind and the ripples they cause in the earth's magnetic field lead to the common brightening, fading, and dancing of the northern lights. Therefore, the greater the solar wind is, the more active the lights will be.
Another interesting fact is the how each color is produced that make up the lights. As stated earlier the solar particles ,made up of electron and protons, slam into the gas particles in the air. As each collision occurs, different colors are produced by the various type of gas molecules.
Each particle of gas glows with a particular color, depending on its electrical state (ionized or neutral) and on the energy of the particle that hits the atmospheric gas. The main colors that are usually produced are green, red, purple, and blue. However, the lights are commonly green in color because of its high energy state while thus often drowning out the other colors. In addition, High-altitude oxygen (about 200 miles up) is the source of the rare, all-red auroras. Whereas, oxygen that is at lower altitudes (about 60 miles up) produces the most brightest and common color of yellowish-green. Other sources are ionized nitrogen molecules that produce blue light and neutral nitrogen glows red.
Overall, the Northern lights further the uniqueness and beauty of the state of Alaska. It is a phenomenon that must be seen to fully appreciate and admire. Even thought tourism stops in the winter, many do visit the state in the dark cold months to experience the rare glimpse of this natural and mysterious occurrence.
Fairbanks during an active show
Text by: The Alaska Almanac 19th Edition
Photos by: AK Division of Tourism
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