NASA scientist say this winter will offer the greatest sky show since 1958, when auroras which are usually seen only in the far north enchanted people all the way to Mexico. The event will be caused by a “solar maximum” – a period when the sun’s magnetic field on the solar equator rotates at a slightly faster pace than at the solar poles. This period is closely linked to the 11-year solar sunspot cycle.
When solar winds collide with the earth’s atmosphere, sparks of light are born that splash across in sky in dancing shapes (arcs, rays, bands, curtains, spirals) and iridescent colors (green, blue, red, orange & scarlet). These ghostly pastel particle streams billow with silent grace — no manmade creation can compete with their mesmerizing beauty!
Aurora result from charged particles that blast out from the sun at a million miles per hour. Upon reaching the earth a couple days later, they get sucked into the planet’s magnetic field and race along down towards the magnetic poles. Along the way, at altitudes of 40 to 600 miles (higher than the Space Shuttle flies), the particles “excite” the gases in the earth’s atmosphere causing them to give off light, often in lovely colors.
Neon lights, in which electromagnetic waves pulse through tubes of gases, tap the same principle. And something similar happens in your dryer when your clothes get static cling. The static occurs when the electrons in the clothes shift from their centers and are picked up by atoms on other clothing, causing your garments to cling magnetically. When you pull the clothes apart, the shifted electrons “snap” back to their original positions. In the atmosphere, after the electrons become excited they snap back to their normal positions and emit a light. Oxygen atoms emit green and red glows, nitrogen emits blue & violet.
Aurora exist near both the north and south poles at every moment of the day and night, but are best observed around midnight when the sky is at its darkest. The southern lights are known as the “aurora australis” and are exact mirror images of the northern “aurora borealis.” In Minnesota, when the sky is dark & clear (as it often is mid winter), the lights are typically visible for at least an hour on one or two nights per week. This winter’s auroral peak will substantially enhance those viewing opportunities. While we enjoyed some lovely emerald green displays in Ely last year, predictions call for some pulsing scarlet and orange lights during this peak winter.
Scientist estimate the aurora generate about 9 billion kilowatt hours of power a year –about ten times the U.S.’s annual electrical needs. Maybe someday we’ll figure out how to tap into this power supply. In the meantime, there’s some concern that this winter’s peak could disrupt mobile phones, GPS and even the national grid.
But aurora still remain the stuff of myth and mystery. Traditional Eskimos believed the lights were deceased relatives trying to contact them. Native Americans felt they could conjure the spirits by whistling to the lights.
And do they whistle back? Maybe. In Siberia, they’re referred to as the “whisper of the stars.” Although most scientists are skeptical, one study claims to have detected audible sound associated with aurora.
Finns refer to the lights as foxes with sparkling fur, hence the phrase “fox fire.” Asian Chuvash natives thought the sky gave birth to child when the lights rolled. Perhaps that’s why Japanese folklore stills holds that a child conceived while the Aurora are playing overhead will be born under an extremely fortunate sign. The Finns have profitably tapped into this Asian fetish by marketing glass igloos in Lapland as honeymoon suite.
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