Aurora

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The popular animated movie “Brother Bear” highlights the important role that the Aurora or Northern Lights played in Inuit beliefs which I found intriguing. There are several Inuit beliefs connected to the Northern Lights. It was believed they were the spirits of the dead on their way to the afterlife, that they were the spirits of the animals they hunted or that they were the spirits of unborn children. However, these were merely beliefs so let’s take a look at the scientific explanation of Northern Lights.

The Aurora are illuminations in the sky which glow in various forms like swirls, shooting rays, ribbons, patches and arcs. They may appear in different colours such as red, yellow, green, blue and violet .However, they most commonly appear in pale green and pink.

Aurora appears above the magnetic poles in both the northern and southern hemisphere. It is known as “Aurora borealis” in northern hemisphere which means “dawn of the north” and is known as “Aurora australis” in the southern hemisphere meaning “dawn of the south”.

Frequent, explosive collisions between gas molecules occur above the surface of the sun. This leads to the emission of free electrons and protons which exit the sun’s atmosphere through holes in the magnetic field. They are transported towards the earth by solar wind and are mostly deflected by earth’s magnetic field. However, the magnetic field is weaker at the poles and therefore some of these electrons and protons enter earth’s atmosphere. These charged particles collide with gaseous particles in earth’s atmosphere emitting lights which are seen as the Aurora.

Courtesy http://www.allcountries.org/photos/finland/finland_photos_55.html
Courtesy http://www.allcountries.org/photos/finland/finland_photos_55.html

The Auroral colours differ according to the gaseous particles which collide. The common pale green is produced by collision with oxygen molecules. The rare red is produced by collision with high altitude oxygen molecules. Blue and purple are produced by nitrogen molecules. The combination of these various colours forms the breathtakingly beautiful and truly magical “Aurora” which illuminates the skies.

References

http://www.northernlightscentre.ca

Images

http://moviesmedia.ign.com/movies/image/cic20031114-02.jpg