Phenomenon of the Northern Lights

Words: 1708
Topic: Sciences
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Abstract

For centuries, people had been marveling at the phenomenon of northern lights, attempting to explain them in the ways available to them: through legends, myths, and supernatural forces. Northern lights, or auroras, still represent a source of awe, and many go on special tours designed to provide the observers with the best view of the lights. The purpose of the present paper is to unwrap the mystery surrounding the phenomenon of auroral displays and consider the scientific knowledge that is currently available to understand the northern lights. The first and the second sections of the paper provide the definition and typology of auroras, and the third part examines the places and times of their occurrence. The fourth section considers the known causes of auroral displays, and the final part provides an overview of the cultural and aesthetical significance of the phenomenon. The main conclusion of the paper is that there is a considerable discrepancy between what has been observed about auroras – for instance, their shapes and colors – and what has been researched about them.

Main

The northern lights are, perhaps, one of the most romanticized naturally occurring phenomena in the world. Anyone who has ever witnessed them – be it in person or on a picture – will agree that this luminous display has a certain charm to it. The northern lights have been extensively hypothesized about, and they frequently appear in folk tales and legends. However, the aurora borealis – the scientific name of northern lights – is a much less researched and understood phenomenon, which is quite surprising, given the popularity surrounding it. The aim of the present paper is to shed some light on the scientific side of the aurora borealis.

Definition of Auroras

Aurora is a general term used to denote multicolored lights that appear in the night sky as a result of the interaction between the solar wind and the Earth’s magnetic field (What are the northern lights?, 2014). The very name of this phenomenon has a mysterious connotation to it since it was named after the Roman goddess of light and dawn (National Aeronautics and Space Administration, n.d., p. 2). However, in the everyday language, it is far more common to call this phenomenon northern or polar lights (Kragh, 2009, p. 378). In scientific terms, auroras are a “natural luminous light phenomenon” (McCorristine, 2013, p. 30).

Despite their name, northern lights are not, in fact, limited to the northern hemisphere, and they can also occur in southern latitudes (National Aeronautics and Space Administration, n.d., p. 2). However, it is more typical to hear about the aurora borealis rather than its southern counterpart – the aurora australis. The aurora borealis typically occurs at high northern latitudes, namely in polar and sub-polar regions, although it can also be observed at lower altitudes, albeit much less commonly (McCorristine, 2013, p. 30). There have, however, also been occurrences of northern or southern lights being observed near the equator (National Aeronautics and Space Administration, n.d., p. 2). Interestingly, auroras are relatively rarely researched and written about since there exists a certain degree of confusion regarding the field that auroras belong to – for instance, astronomy, meteorology, or geophysics (Kragh, 2009, p. 378).

Types of Auroras

Apart from the geography-based classification of auroras into northern and southern, there does not appear to be a typology of different auroras that is based on their behaviors, shapes, colors, or other characteristics. Nevertheless, one can certainly discuss the distinctively different shapes and colors that auroras can take, and it is common to meet descriptive, rather than analytical, overviews of different types of auroras. Essentially, auroras represent constantly changing light shapes of different colors – typically green, but also red, violet, blue, yellow, white, and pink. Light green and pink, in particular, are the most frequently occurring colors in auroras (Northern Lights Centre, n.d., para. 2). One defining characteristic of northern lights is that they are rather unpredictable: they can appear scattered like clouds or be very bright, they can look like long arcs crossing the entire sky or they can spread out in rays. According to the National Aeronautics and Space Administration, in some cases, the shape of auroras can make them be confused with the Milky Way. At other times, auroras resemble thin clouds, but they can also swirl and fold in the sky, similar to curtains. Moreover, if northern lights initially take one particular form, it does not necessarily mean that they will keep it for the entire duration of their occurrence. Auroras tend to constantly change from one shape to another. Thus, there is a great variety of shapes and colors that auroras can take (National Aeronautics and Space Administration, n.d., p. 2).

Time and Place of Occurrence

As mentioned previously, auroras typically occur in the outmost northern and southern latitudes. At the same time, it does not mean that northern and southern lights are strictly limited to these particular geographical areas. These phenomena occur in the vicinity of the Earth’s magnetic poles that do not correspond to the planet’s geographical poles. This fact explains why northern lights may be observed in the western hemisphere – for instance, as far south as New Orleans – yet they do not take place in the corresponding areas in the eastern hemisphere (Northern Lights Centre, n.d., para. 10). To a considerable extent, the location of the auroras’ occurrence depends on geomagnetic events, which, in turn, depend on the Sun. An unusually big event will thus have a bigger impact on the Earth’s atmosphere, which explains why the lights can be observed further than usual to the south (What are the northern lights?, 2014).

However, even though the occurrence of auroras is possible in lower areas, it is not necessarily common. Consequently, if one wants to receive a full northern light experience, they travel to the northernmost parts of North America and Eurasia. In North America, the northwestern parts of Canada and Alaska provide for the best location to observe the lights, and in Europe, one should go to Iceland, Norway, or Siberia (Northern Lights Centre, n.d.). The reason why southern lights are not as commonly discussed as northern lights is that they primarily occur around Antarctica and in the southern part of the Indian Ocean, which makes it rather difficult to observe them. As far as the timing is concerned, winters are typically the best seasons to view the lights. Auroral activity has been found to be cyclic, and it typically reaches its peak every eleven years (Northern Lights Centre, n.d.).

Causes

Both the northern lights’ shapes and colors, as well as the time and place of their occurrence, can be directly observed. However, understanding the causes and mechanism of their appearance is a more complex task. Researchers have come to understand that auroras are a byproduct of the interaction between the planet’s magnetic field and the solar wind – a “stream of charged particles escaping the Sun” (What are the northern lights?, 2014, para. 1). When the solar wind gets close to the Earth, it interferes with the planet’s magnetic field, allowing some of the particles to enter the atmosphere. These particles collide with different gases, primarily, with oxygen and nitrogen. Their atoms absorb the energy released by the electrons, thus “exciting” the gases. As these gases slowly return to their normal state, they start to glow because of their photon emissions. Depending on how many electrons enter the atmosphere, they may interact with enough oxygen and nitrogen atoms to make the photon emissions noticeable to a human eye, even though the light comes from high altitudes of up to 400 kilometers. Scientists have also discovered that the color of the lights depends on which one of the two gases become excited, and to what extent. Highly excited oxygen is the most common scenario that results in the green color. Nitrogen usually emits blue light, and different combinations of the two gases produce blended colors such as white and purple. It is, however, still unclear what determines the shape of auroras (National Aeronautics and Space Administration, n.d.).

Cultural and Aesthetic Dimension

Finally, it is worth noting the cultural and aesthetic dimension of northern lights. The phenomenon has been widely popularized by the northern countries as a miraculous and beautiful event, with the aim of attracting tourists. In fact, auroras have virtually become a trademark of Norway, and northern light chase tours have certainly occupied a niche within the tourist industry (Bertella, 2013, p. 96). Apart from that, the phenomenon has gained particular cultural and mythological significance in the regions of its occurrence. Thus, for instance, the Scandinavian societies believed auroras to be bridges by which the gods arrived on Earth from heaven. Folklore about the lights has spread as far as China, where the lights were portrayed as the sky’s dragons or serpents.

In North America, the indigenous tribes thought that the northern lights were the lanterns that spirits took with them to look for the souls of dead hunters. On the other hand, Eskimos believed that auroras were souls playing with each other. Even these days, it is a custom in Norway to marvel at the lights and not misbehave in any way when looking at them. Apart from that, people also used to view the northern lights as predictors of certain weather conditions, yet the content of the forecast varied across different communities. Thus, the Scandinavian inhabitants believed that the northern lights predicted snow and cold weather while the Eskimo tribes believed that the playful spirits would bring good and favorable weather (National Aeronautics and Space Administration, n.d.). Perhaps, it is the mysterious status of auroras that prevented them from being researched and explored more thoroughly.

Conclusion

When one looks at northern lights, they usually tend to admire their beauty rather than consider the causes that underline the lights’ shapes and colors. While the auroras’ aesthetic dimension cannot – and should not – be denied, it is, however, important to shift the focus from mere observation to exploration. Given the modern advances in technology, scientists are well-equipped to discover the great mystery that northern lights still are. Researchers have certainly already made several important steps toward understanding this phenomenon, but further research is nevertheless necessary.

References

Bertella, G. (2013). Northern lights chase tours. Journal of Northern Studies, 7(2), 95-116.

Kragh, H. (2009). The spectrum of the aurora borealis: From enigma to laboratory science. Historical Studies in the Natural Sciences, 39(4), 377-417.

McCorristine, S. (2013). “Involuntarily we listen”: Hearing the aurora borealis in nineteenth-century Arctic exploration and science. Canadian Journal of History, 48(1), 29-61.

National Aeronautics and Space Administration. (n.d.). AuroraWeb.

Northern Lights Centre. (n.d.). Northern lights. Web. 

What are the northern lights? (2014). Web.