NATURE NOTES
The Northern Lights are a must-see for any mountain lover, and are a truly life-affirming experience. They can also be frustratingly hard to see though, especially if you don’t happen to be in the right place at the right time. Or awake…
Two things spring to mind when I think about the Northern Lights; venison sausages, and ex-Stone Roses front man Ian Brown. The latter, simply because he has a cool-as-you-know-what song of that title. The sausages, well they’re even more special because not only were they my first sausages made out of a deer, but they proceeded, by 10 minutes, my first (and only) sighting of the phenomena known as the Northern Lights. Twenty long years ago, word spread around the Highland pub I was eating in that the Northern Lights were showing, and the pub emptied of all but a few weary locals. The car park filled with Northern Light virgins and experts alike. A green, wavering curtain of dancing light illuminated the northern horizon of that October night and changed the lives of the assembled crowd.
The correct term for the light referred to in the phrase ‘Northern Lights’ is aurora. These happen at both the north and south, Arctic and Antarctic regions. Sometimes called polar lights, auroras are more properly named Aurora Borealis for the northern and Aurora Australis for the southern. Both work in the same way and are often in sync, reacting at the same time.
The simple way to put it is that the displays appear when there is a disturbance in the magnetosphere, namely at the hands of solar winds. These excite electrons and protons to such an extent that they create intensities of different lightwaves and colours. When they’re happening, the light-emitting areas sit over the poles of Earth in what are known as auroral ovals. In particularly strong geomagnetic storms these expand, pushing towards the equators and bringing the light display to lower latitudes. For the best show of lights, the auroral arc needs to be at its closest to the equator and the magnetic pole needs to be between you and the sun. This is known as magnetic midnight. The best displays coincide with the peak of an 11-year cycle of geomagnetic storms, and again three years after the peak. A display will evolve during the night, beginning with a lowdown glow and progressing towards the exciting shapes, then fading in the reverse order. The lights can take the form of curtains, patch
