Northern Lights: Nature’s Television
From harbinger of dawn to harbinger of doom, the northern lights have puzzled Eskimos and scientists alike for centuries. Now, with satellite images to transmit information about the atmosphere of the earth and activity on the surface of sun, an understanding of the phenomena is within our grasp.
The northern lights, or aurora borealis, are due to the interaction of solar emissions and the earth’s magnetic field. The northern lights have a South Pole counterpart called the aurora australis. Between 40 and 600 miles above the earth, solar winds strike the earth’s magnetosphere, the magnetic barrier between the earth and space. According to the Poker Flats Research Range website (pfrr.alaska.edu), this interaction between the solar winds and the magnetosphere generates electrical energy in the ionosphere.
Poker Flats Research Range is a scientific rocket launch site in Fairbanks, Alaska run by the University of Alaska’s Geophysical Institute. Due to its high latitude, the range is one of the premier aurora viewing spots in the country.
Measured in Terms of Gigawatts
The electrical energy generated in the atmosphere is measured by satellites in terms of gigawatts, or billions of watts (compare that to a 60 watt light bulb). The higher the wattage detected by the satellite, the more active, and therefore, more visible the aurora.
According to the Space Education Center web site, auroras increase with solar activity such as sunspots and solar flares. Solar activity usually changes in intensity on an eleven-year cycle. The current cycle, number 23, started in 1996 and is expected to peak this year.
In much the same way electrons are sent through a vacuum tube to smash against the phosphors on the inside of television screens, the aurora borealis shimmers in the sky whenever electrons and other charged particles careen into oxygen and nitrogen particles in the vacuum of the earth’s upper atmosphere.
Partical-Element Collisions
Each element emits a specific spectrum of color when energized, and these emissions are responsible for the green, red and blue colors of the aurora. At higher elevations, the particle-oxygen collision emits an all red aurora, while at lower elevations, oxygen emits a brilliant and more common yellow-green.
Nitrogen, on the other hand, emits either blue light or red light, and the purplish-red lower boundaries of the northern lights.
The northern lights are too high to be flown through by conventional aircraft, but the space shuttle, which flies at 190 miles above the earth, can penetrate the phenomenon.
Some people claim that the northern lights influence the weather, and scientists, while not confirming the assumption, say it could be possible. People also claim the lights emit a noise. Scientists say noise from the aurora is less likely because of the phenomenon’s occurrence in only high altitude and vacuum conditions.
Samet Bilir a freelance writer who writes about online shopping products. You can read more about his work at azframes, a website for digital picture frame reviews.
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