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Aurora Borealis & Aurora Australis: Nature’s Mesmerising Light-Show

BY Dipanjana Mukherjee November 22, 2019
Aurora Borealis

Aurora at Fairbanks, United States. (Tommy Tang / Wikimedia Commons)

Aurora, the goddess of light in Roman mythologies, was also considered to be an embodiment of dawn. It is after her that the French philosopher, Petrus Gassendus, had coined the terms ‘Aurora Borealis’ and ‘Aurora Australis’, way back in the 16th century.

The Latin term ‘Aurora’, means ‘light’, while the terms ‘Borealis’ and ‘Australis’ indicate ‘Northern’ and ‘Southern’ respectively. As the name suggests, Aurora Borealis and Aurora Australis are lights that shine over the polar skies of the northern and southern hemisphere, respectively. They are visible in a specific polar belt in each of the hemispheres and appear as a ripple-like show of fluorescent colours in the dark night sky.

How are Aurora Borealis and Aurora Australis formed?

When there is an onset of storms in the sun’s surface, it releases a vast amount of solar charged particles, some of which tend to travel towards our planet. Once they come in contact with the earth’s atmosphere and magnetic field, a reaction takes place which hypes the atoms present in the scenario and lights them up. This further causes these magical lights to form and take shape.

When do Aurora Borealis and Aurora Australis occur?

Aurora Borealis and Aurora Australis are phenomena that depend entirely on solar activities and therefore aren’t very predictable. One can only be sure of them occurring about two hours before they actually occur. There are a few things that contribute to seeing the best, most beautiful exhibit of these lights, the most prominent one being the solar cycles. The sun has an 11-year cycle. In these 11 years, there are phases where the solar activities are extremely high, and then there are phases where they stoop really low. These changes in solar activity levels affect the formation of the lights drastically. The higher the solar activity, the more charged particles come Earth’s way, and the more intense the formation of lights is. On the other hand, when the situation counteracts and the solar activity is low, there are much lesser charged particles, and the aurora lights are comparatively dull. The year 2014 marked the most glorious of all aurora exhibits in the 11-year tenure of the cycle.

Aurora borealis.

Aurora borealis. (pexels)

It is evident that the lights never stop occurring since there is always some amount of solar activity taking place. However, in order for human eyes to see the phenomena occur, an ideal time and setting is required. The view can, however, be experienced in its true magnificence, only when it is viewed in the dark. This automatically cancels the possibility of watching the aurora during the day. We must keep in mind that in the two poles, the days don’t go through the proper cycle of brightly lit daytime and dark nights. Rather, the duration of the ‘day’ depends entirely on the seasons. As far as the time of the year is concerned, winter is deemed the most ideal time to witness the Aurora Borealis and Aurora Australis. The winter season in the North is from April to August, and in the South, it is March to September.

Aurora from space.

Aurora from space. (NASA)

Why do we see Aurora Borealis and Aurora Australis only near the poles?

Aurora Borealis can only be seen at very high latitudes, beyond the Arctic Circle in the North. It can be best observed from areas such as Norway, Finland, Iceland, Alaska, Sweden, and even in some parts of Canada. Aurora Australis can be seen in the higher latitudes of the Southern Hemisphere, particularly in Antarctica, and in certain places of New Zealand. The Auroras can’t be seen everywhere, and the reason for the same lies in the way the Earth’s magnetic field acts. Since the magnetic fields of our planet are weaker near the Poles, the solar-charged particles find an easier entrance to the planet’s atmosphere through them. Consequently, the charged particles collide with the particles present in the atmosphere to form these beautiful displays of coloured lights.

Artist rendering of Solar Storm striking earth’s magnetic field. (NASA)

Do Aurora Borealis and Aurora Australis affect the earth in any way?

The solar energy charged particles that enter the earth are foreign materials. When they enter our atmosphere, they expand the same by a tiny margin. This disturbance disrupts the electromagnetic field, and affects the radio waves too, thus disturbing the transmission of information. The solar particles’ magnetic energy, when combined with the Earth’s magnetic energy, holds the potential of disrupting the proper functioning of electrical devices. In extreme cases, the lights might be a sign of the onset of a geomagnetic storm. Although such extremities have not been witnessed of late, and neither do they affect the onlookers as they occur such high up into the atmosphere. Geomagnetic storms hold the potential of wreaking havoc to the technological aspect of our planet, if not the environmental.

Related: What Would Happen if Solar Storm of 1859 Occurred Today?

What would happen if we didn’t have the Aurora lights?

As of yet, there isn’t any research or answers to this question. It will perhaps not affect the world much to not have the Aurora lights flickering above our heads. It would rather lead to the stabilization of the earth’s magnetic field and the atmosphere. Probably the usage of instruments that require electronic, magnetic and radio wave assistance will be easier as well. On the other hand, we will be missing out on nature’s own spectacular light show. The lights also stand as a record of the solar activities and it will become a lot tougher to document the same without the assistance of the Aurora phenomenon. Thus we can conclude, the eradication of this occurrence will perhaps not affect the Earth much. It will, however, conversely affect a lot of research, and there would be one less wonder for us to ponder about!

Aurora lights and mythology

The Aurora lights have had many mythological references and associations since mankind first took note of them. In many indigenous communities, the Northern and Southern lights are taken as the spirits of their ancestors that watch over them. Many believed it carries with it bad omens of some terrible calamity. In Norse mythology, the lights were taken to be proof of the existence of their gods, and were thus of religious importance to the Vikings.

For ages, this natural phenomenon has awed mankind, so much so that it has evolved into a literal hobby for some. Called ‘light chasing’, the activity is quite similar to that of bird watching. Here, however, instead of going to exotic jungles to watch pretty birds, one goes to Arctic countries, and the like to experience the Aurora lights. These lights are at once mysterious, stunningly beautiful, and a scientific marvel, depending on how you perceive them.

Enjoyed this article? Also, check out “Light Pillars, an Insight into Nature’s Spectacular Optical Phenomenon“.

Fact Analysis:
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