The northern light

Witnessing the ever-changing northern light, which is also known as the Aurora borealis, is truly a sight to behold.

The northern light is a physical phenomenon that occurs when the solar wind is more powerful than normal. The wind from the sun contains electrically charged particles that are driven towards the poles by the Earth’s magnetic field and collide with gases (nitrogen and oxygen) in Earth’s atmosphere.

The released energy creates the electromagnetic lights which is the visible aurora. In the northern hemisphere these lights are known as northern light, i.e. Aurora borealis, and the southern counterpart is called Aurora australis.

The phenomenon can be observed in the night sky in a belt around the magnetic poles. The light is of changing character and may vary in shape, colour and strength. The northern lights are located at a height of between 90 and 200 km above the ground, in the part of the atmosphere called the ionosphere. The colour of the aurora depends on how high up in the atmosphere the phenomenon does occur. Northern light above 180 km provides red light, between 120 and 180 km yellowish green light and below 120 km bluish violet light. Most often, the aurora borealis appears as a faint green or light rose.

To see the great northern light displays, people will have to head north towards the Arctic, above latitude 60 degrees at the least. Canada, Alaska, Russia and northern Scandinavia are great viewing spots. The northern lights are the most likely to see when there are clear skies or low clouds in the sky. Secondly, it must be dark outside! That means that winter in northern Sweden has the best conditions. In Swedish Lapland it is possible to see the lights from late September to early April, with October to November and February to March considered the best periods; the span between 9pm and 2am is often prime watching time. One has to bear in mind that the northern light is a sporadic phenomenon, occurring randomly for short periods or perhaps not at all.

People travelling north are encouraged not to become obsessed with the single goal of watching the northern light; too see the heavens with a swirling light is impossible to guarantee due to changing and unpredictable weather conditions. People should plan a rewarding winter holiday in general, with a lot of daytime activities; beholding the aurora borealis is then the icing on the cake.

Abisko, approx. 100 km northwest of Kiruna town is said, to be one of the best spots in the world to see the northern lights as surrounding mountains keep the skies almost always clear. But even there you need some luck to get a good sighting. The best sightings are away from artificial light (caused by large settlements) and moonlight.

At the coming of the night: Step just out the door of your Reindeer Lodge cabin or walk the few metres to the shores of River Torne, or join a Sámi northern light photography tour or a tour by snowmobile into the surroundings of Jukkasjärvi. Most importantly, look up at the sky at dark.

In North Sámi language the ancient phenomenon of the northern light is called Guovssahas, i.e. the flickering light.

Find out more about the northern light on the Swedish Institute of Space Physics’ website.

Link to some aurora forecast above Europe by the Geophysical Institute of the University of Alaska Fairbanks.