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Compass needles, like excited children, were restless for hours before the big show, quivering on their pins in aircraft and boats. Mine trembled in a desk drawer, unable to direct my curiosity, alone with its agitation.
It took a call from a friend to take me out-of-doors on a cold night four winters ago to see a command performance: Aurora Borealis. The Northern Lights.
The auroras I remember seeing in the skies over northern Idaho were pale gossamer fingers of light that seemed to dance upon the horizon. But what I saw that night in central Oregon was far different. A ruby-red curtain hung down from the rafters of heaven, undulating overhead as if shaken by some unseen hand or stirred by the wind. It was nervous-making.
Only some celestial catastrophe, broader than our meager planet, could create such a shroud. And what did its blood-red hue portend?
Huge tongues of flame, 16 times the size of Earth, had erupted from the surface of the sun about a week before that night, sending a gas of highly charged atomic particles streaming outward into space. When the particles reached Earth they passed around it, as though it were a rock in a creek. And as they flowed by they followed a path of least resistance toward the poles where they excited electrons in the Earth's magnetosphere to the point where they emitted energy, which was seen as the aurora.
In the far north, where nature's light shows are more common, the coloring of the aurora is almost always a pale, whitish green or pinkish rose. In more southerly latitudes, the more prominent tint is deep red or green. The reason for the difference is the angle of light refraction.
When the red curtain appeared in the skies of Europe during the Middle Ages it was taken as a sign of conflagration and holocaust. God was signaling his displeasure, or giving warning of impending disaster.
Among Eskimos, who see a pale color of light in the low latitudes, the aurora borealis is less ominous. Some see the play of children in the heavens. Others claim that if you stand still and whistle softly the lights, like living creatures, will draw closer.
Sunspots spout the solar winds that turn on the northern lights. When solar storms are raging, the Earth's polar heavens respond with light and color. When the sun's surface burns quietly, auroras do not appear.
In the mid-1600s astronomers could find few sunspots on the sun. The glowing disc in the sky was clean-faced and free of storms for decades, emitting less radiance than at any time since. Those were the years of the "Little Ice Age," when the Thames River froze in London.
Usually, sunspots appear in cycles. Every 22 years since 1749 they have reached a peak, then subsided. The most recent peak occurred in 1989-90 and their activity is now subsiding, but the number of geomagnetic storms over Earth, and subsequent appearances of the Northern Lights, is often greatest at this time.
Although one can never be sure when the lights will appear, the nights from October to April are favored performance dates. And now, with geomagnetic storms raging frequently, is a good time to be watching.