BOREAL NIGHTS, NORTHERN LIGHTS
Vermont is just close enough to the boreal region, the northernly area below the arctic, to see aurora borealis, more often called northern lights. Alas, it’s just far enough to the south for big, colorful displays to be rare. That is especially true in years like this, when we are at the point in the sunspot cycle known as the solar minimum.
Sunspots are “cool planet-sized areas on the Sun where intense magnetic loops poke through the star's visible surface.” Though unmentioned by astrologers as far as I know, their bursts of electromagnetic particles cause problems here on Earth, 93 million miles away, for instance by disrupting communications transmissions. The best northern lights I ever saw, so powerful that they were overhead as well as on the horizon and lasted for hours, came on a night when it was impossible to pull in any of the FM radio stations I knew—a tipoff that I should go outside and check the sky. There were a half dozen FM stations on the air, but all of them were speaking Spanish.
There’s a scene in a Vermont novel in which the man wakes his wife because she always wanted to see the northern lights, and somewhat grudgingly she rouses and agrees to be towed along. As they go downstairs, she says, “But it’s almost dawn!” “Honey—that window faces west.” That kind of night.
If seeing the northern lights is part of your life mission as a Vermonter, how would you know they were out there? They don’t make any noise, after all, and most don’t traumatize electronic transmissions, and I don’t know of any newspaper that carries an aurora probability report.
There is one, though, if you go to the Internet site that furnished the above definition of sunspots: www.spaceweather.com. This fabulous resource includes information about many other things than auroras; for instance, on Dec. 1 they had the best picture of Comet Holmes I’ve seen. Every day they publish the Boulder Sunspot Number (there’s also an International Sunspot Number put out by the Sunspot Index Data Center in Belgium). In Spaceweather’s explanation of the numbering systems, they say “As a rule of thumb, if you divide either of the official sunspot numbers by 15, you'll get the approximate number of individual sunspots visible on the solar disk if you look at the Sun by projecting its image on a paper plate with a small telescope.”
On their sunspot timeline from 1610-2000, there are four times since 1950 when the number went above 150. On Dec. 1, it was 12, because a new sunspot, provisionally named 976, was just observed—and had already begun to deteriorate. The website is so thorough that they even have a graphic showing how many sunspots are on the side of the sun facing away from the Earth (none, currently). As I said, it’s not a great year for northern lights. But as sure as shooting stars, there will be a solar maximum as the cycle continues (My memory says it’s an 11-year cycle. Let’s see…”The main periodicity in the Sun's activity is the 11-year cycle called the solar cycle.” No Alzheimer’s yet.)
Spaceweather’s graphics include a representation of the Auroral Oval, the section of the northern hemisphere where auroras are most likely to occur. The map is color-coded, with yellow denoting the fringe areas (like us) and red for the central places (like the Yukon and Hudson’s Bay). The key to it all is one of the three North Poles: the Geomagnetic North Pole, the northern axis of the magnetosphere, the magnetic field that extends from Earth into space. The solar particles hit this set of magnetisms and get funneled toward the North and South Geomagnetic Poles (there are aurora australis, or Southern Lights, too). When they hit the atmosphere, the energy that’s released appears as northern lights.
Since I brought up the subject, I’d better do a quick review of what you may or may not have learned in school about north poles. The Geographic North Pole is the one on maps, used for instance for countries to fight over the oilfields that will become accessible once all the polar ice melts. The Magnetic North Pole is the one your compass points toward; alas for the wisdom of compasses, it has moved 684 miles since it was discovered at 70 degrees N-96 degrees W, and at its current speed of about 25 miles a year could be in Siberia in another half century.
The North Geomagnetic Pole moves, too, but not as much. Currently it’s near Thule (Qaanaaq) in Greenland, about 500 miles east of the Magnetic North Pole.
Getting back to northern lights: for those with a serious interest—photographers, ham radio operators, just dedicated skywatchers—Spaceweather maintains two telephone message services. For $4.95 per month, you get the Space Weather Alert, which will let you know about big sunsports, solar flares, and geomagnetic storms (that is, the stuff that causes northern lights). For $6.95, you get the Backyard Astronomy Alert, which adds things like planetary alignments, meteor showers, and space station fly-bys. If no schools have tapped this resource, perhaps they should, after which those who were interested in northern lights could set up a phone tree. Of course any group of interested individuals could do the same. I’ll bet if enough of us contacted Vermont Public Radio, they’d include a northern lights probability report in their Eye on the Night Sky feature—which is also accessible online.
If you want to search further, www.athropolis.com (all thing arctic) has a set of northern lights links, as well as interesting features like a map of the treeline and reports on current temperatures.
If it seems cold this winter, remember that the northern border of Vermont is at 45 degrees longitude, on a scale that runs from zero to 90. In other words, THE NORTHEAST KINGDOM ISN’T EVEN HALFWAY TO THE NORTH POLE, if you start from the Equator.
As much as to say, it’s a big place up there in the Yukon, Northwest Territories and Nunavut, and some big things take place when the stars come out and dance about, as Ronald Reagan’s favorite poet Robert W. Service put it. If you want to see what we’ve been missing down here in the yellow zone of the Auroral Oval, go to Nordly’s Northern Lights, at www.northern-light.no. (The “no” part stands for Norway.) Do it soon, because they appear to have stopped holding monthly aurora photograph contests at the end of 2006, and maybe the archive will disappear as well.
The stuff sent in by the small but highly competitve auroral photographic community includes not only green but also red, yellow, blue and purple northern lights; “coronal” bursts that come from one area of the sky and seem to shower across everything; and more ribbons and flares and other forms than you could imagine. On a frigid-to-the-rigid winter night, logging on to that collection it sure beats watching loose snow blowing off the tops of dune-like drifts.