The Northern Lights
From one side of the sky to another a drapery, woven of light and colour is wafted; now here now there, first one then two, then several bands, one above the other, never at rest, and never the same form, hither and thither the folds sway with a soft, fascinating motion, as from one end to the other waves of light chase each other, over-taking, crossing, meeting, while the lower, intense border, displays the loveliest colours of red and green, the upper one fading into the dark background
Extract from: 'Under the Rays of the Aurora Borealis' 1882-1883 by Sophus Tromholt (source: FRR)
Tromholt was a Danish scientist, who took part in an International Polar Research Expedition ahead of the first International Polar Year, dedicated to finding out more about the aurora and what caused it.
Discover the secrets of the northern lights!
More about the Northern Lights
In the early 17th century Galileo Galilei called this phenomenon Aurora Borealis. Aurora was the Roman goddess of dawn, and Boreas was the Greek name for the north wind. Galilei thought an aurora was caused by the sunlight reflected from the atmosphere.
This display of coloured light is caused by the interaction of the solar wind, and the Earth's magnetic field, and atmosphere. The solar wind carries electrons, from the sun's atmosphere into space. These charged particles/ions are drawn into the Earth's magnetic field, particularly at the North and South magnetic poles, and down into the Earth's ionosphere (upper atmosphere). When the particles collide with gasses in the atmosphere energy is created. Some of this energy is given off in the form of light emissions, - the Aurora Borealis or Northern Lights, and in the Southern Hemisphere the Aurora Australis.
Aurorae can be red, green, blue and violet. Different colours are produced when the charged particles collide with different gasses, in the atmosphere, mostly compounds of nitrogen and oxygen. The lights can take various forms; the most common types are arcs, bands and curtains. These forms may be shaped by the Earth's magnetic field lines.
Up to 1000.000 megawatts of electricity can be generated by the solar wind in a single auroral display. It can interfere with power lines; radio and TV broadcasts and satellite communications. The Sodankyla Geographical Observatory, in Finnish Lapland, is an important centre for the study of this geophysical phenomenon. Scientists study auroras to find out more about solar wind and how it affects the earth's atmosphere and also to explore the possibilities of harnessing the energy
The Aurora Borealis can be seen mainly in the Northern Hemisphere, particularly the far north, but sometimes as far south as Europe. The geo-magnetic activity can take place at any time, day or night. People observe activity on the Sun's surface, study the speed of the particles being thrown off the surface into space and try to predict where and when the aurora will happen. These observations and predictions are known as space weather.
The best time to see the colours are on a dark clear night, with no clouds. Auroras are most commonly seen in September and October, and March and April. In Finnish Lapland the lights are in the sky for 200 nights per year. The Northern Lights are a huge tourist attraction in countries around the Arctic Circle, including Norway.
See clips from a BBC programme featuring Joanna Lumley experiencing the Northern Lights - 'Joanna Lumley - In the Land of the Northern Lights' on youtube
Indigenous peoples across the Arctic, were the first to witness the phenomenon, and had many explanations and names for this amazing display of celestial light. In Finland there are numerous folk tales about the origin of the lights which are known as Fox Fire or in Finnish 'revontulet'. The most common story features the Arctic Fox, and his bushy tail. In one version as the fox runs across the Northern landscape, its tail touches the mountains, and causes sparks to fly off into the sky as the Northern Lights. In other versions the fox's brush like tail sweeps or sprays up snow into the sky. However there is an old Finnish word which is similar to the word for fox but means making magic. So perhaps the meaning of 'revontulet' is magic lights?
Do you think you can see the Northern Lights in Britain?
Explain why you have come to this decision. What evidence do you have to support this?
Write a poem about the Northern Lights.