Do you know about Aurora? Read on to know more
Nature is beautiful and science is more beautiful as it can describe Nature.
You are walking in the bare lands of northern U.S.A. on a dark night and suddenly notice some faint light in the sky. You suddenly take your phone out, click a picture and those faint whitish glows turn into some colourful patterns. Congratulations, you are witnessing Aurora Borealis. Scientifically the disturbance in the Magnetosphere followed by ionisation of atmospheric constituents, results in emission of light which are seen in places near magnetic poles known as Aurora.
The Reason Behind: Solar Wind
Solar wind interferes with Earth’s atmosphere and causes disturbance in the Magnetosphere. In magnetospheric plasma, there are charged particles which can get precipitated into the upper atmosphere due to major disturbances caused by increase in the speed of Solar wind. This precipitation leads to ionisation and excitation of gases, which then emit light with different patterns and colours.
Occurrence: The Places
In both hemispheres, latitudes between 10 to 20 degrees with a width of 3 to 6 degrees Aurora are seen. In the northern hemisphere it is known as Aurora Borealis. It can be seen from Alaska, Canadian lands, Greenland, Norway, Sweden, Finland, Iceland, northern United States and Russia. It’s called Aurora Australis in the southern hemisphere and can be seen from Antarctica, Chile, New Zealand, South Africa and Australia.
Appearance: Treat to the Eyes
Though aurora can’t be seen by naked eyes, you can just use your smartphone to witness the majestic beauty of it. Red coloured aurora is caused by oxygen gas excitation at high altitudes. At lower altitude green aurora can be seen because of excited atomic oxygen and excited molecular nitrogen. At even lower altitude, molecular and ionised molecular nitrogen causes blue aurora.
Sometimes Ultraviolet, Infrared, yellow or pink coloured can also be formed even in other planets like Mars, Jupiter and Saturn.
Cycle: Changing with Time
You can see the patterns of aurora changes with time. Initially they glow in wide lines then gradually tend towards coronas and then again fade away. Aurora corona is such a state when charged particles flow towards the direction of the observer. So, the aurora can be seen as oval shaped glowing lines.
Some Interesting Facts: Named After Gods
The Roman goddess of the dawn is “Aurora”. She mythically used to travel from east to west to announce the arrival of the Sun. The term aurora is taken from her name. The words “borealis” and “australis” are derived from “Boreas” and ‘Auster”, the gods of north and south winds respectively.