Aurora Borealis Explained

I have always been curious and amazed at this natural phenomenon when I came to know of its existence at the age of 14. I was keen to know why it only occurred strongly in the tips of northern and southern hemisphere. In addition to this, I was keen to know why it only appeared in winter.

The aurora borealis or commonly known as northern lights was named after the Roman Goddess of Dawn, Aurora, and the Greek word for north wind, boreas [1]. Many do not know that you can witness this phenomenon in the southern hemisphere as well, somewhere near Australia and New Zealand. This phenomenon is then called southern lights or aurora australis.

The aurora borealis do not just appear out of nowhere to beautify the sky. The Finnish used to believe that the lights were caused by a magical fox that swept its tail across the snow and onto the sky [2]. The Vikings however believed that the lights were caused by the swords and shields of war heroes during battles. And the myths and folklore continue from the Norwegians, Eskimo tribes and what have you.

fox

Courtesy of Lhuin Deviant Art.

Moving forward to current age, the northern lights can be seen from many countries such as Finland, Norway, Scotland and more. In 2015 however, the lights activity was so strong that it can be viewed even in France [4]! This is not just rare but amazing. An even more bizarre sight is seeing it in Singapore! This is true in September 1909 when there was a solar storm [5].

As with most things, there is a science explanation to it. The sun has 4 states of matter namely; solid, liquid, gas and plasma. Plasma are charged particles in gas form. The energy from the core of the sun allows these charged particles to charge out to the surface of the sun, going towards the direction of the earth in what we call the sun wind.

auroraborealisscience

Picture showing the Sun wind and magnetic field of Earth.

The earth has a magnetic field depicted as the purple pattern above [3]. It is weakest in the north and south poles. At these weak points, the sun wind is able to come in contact with the earth’s atmosphere creating the amazing light shows. When the plasma interacts with the oxygen, it forms the green light. When interacted with nitrogen however, it forms a pink or purple tinge. The altitude of the interaction also plays a part in the colours formed.

1.png

So this is one of the first few shots that I took when I was in Iceland. I have taken a wide angle shot at ISO800, shutter speed of 30 seconds with protune set to ‘on’. I found these settings to capture the pictures well. The night I saw it, wasn’t too great a night but good enough to see it in the sky. What I did learn is that the northern lights are quite a pain to shoot. It goes off quicker than you think and comes when you least expect it. I literally had to quickly mount my tripod and just hope for the best!

2

It was really nice to see how the lights formed and how wonderful the patterns and colours look. It was indeed a phenomenon. My bucket list that I have had since I was 14 years old has indeed been fulfilled. It was an amazing sight that I will never forget.

3

At this stage, the lights are moving quite fast and though there are not much patterns, it was still an amazing view. This is me facing the light show and enjoying every moment of it. Even though it was -2 deg Celcius and the fact I had to stand still for 30 seconds per photo in the blustering wind, was well worth it!

4.png

This is my friend and I. And yes, we stood like that for 30 seconds. Yes, there were people looking however all that matters is us having fun and getting great pictures. There are limitations on viewing the northern lights however. And I recommend everyone who wishes to view them to read up about them to prevent getting disappointed.

Which gets me to my next point. Why is this called a phenomenon? Well, for many reasons. Weather plays a part. If it’s a cloudy day, it is more difficult to see or not visible at all. The interaction is happening at a higher altitude than the clouds and therefore could be blocked by heavy clouds. Also, in winter, the sun is “hiding” most of the day. If the sun is out, the bright light from the sun will overpower the northern lights. Meaning to say, surprisingly the light show is happening all the time whenever there is sun wind. It is just not visible when there are other forms of light anywhere. Hence, viewing the light show in the dark is best. I was viewing it when it was pitch black, literally.

And there you have it, the aurora borealis explained.

References

[1] Cliver, EW & Silverman, SM 2000, ‘Low-latitude auroras: the magnetic storm of 14–15 May 1921’ Journal of Atmospheric and Solar-Terrestial Physics, vol. 63, pp. 523–535.

[2] Gill, N.S. “What Is The Classical Origin Of The Aurora Borealis?”. About.com Education. N.p., 2016. Web. 29 Jan. 2016.

[3] iSun|trek,. “Science Of The Northern Lights Aurora Borealis”. N.p., 2014. Web. 4 Feb. 2016.

[4] Luminarium.org,. “Aurora Borealis, The Northern Lights, In Mythology And Folklore.”. N.p., 2016. Web. 4 Feb. 2016.

[5] Thelocal.fr,. “France Treated To Rare Northern Lights Show”. N.p., 2015. Web. 2 Mar. 2016.

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