The AURORA or we also Known as a "The Polar Lights", The Northern Light (Aurora Borealis) or The Southern Light (Aurora Australis) are one of most beautiful displays of nature. Apart from these,
"Black Aurora or Anti-Aurora", "Electron Aurora", "Proton Aurora", etc.... are also.. If this is done in depth study then this topic is quite big but i'm just giving an overview of them. So.....There are mainly two types of aurora :-
- Diffuse Aurora.
- Discrete Aurora.
Other planets have their own aurora but in this article I'm just writing about Earth's Aurora. In ancient times, people thought that the spirits of their ancestors can be seen dancing within the light of the aurora. In
Norse Mythology the
Vikings believed that the aurora was a bridges of fire to the Asgard and other says they're the light reflected of the
Valkyrie's shields and people in Finland thought it was the
Archangel Michael and
John Travolta fighting with the
Devil. And many other kinds of superstitions were spread out But they're all wrong and myths, They are actually caused by
The SUN.
First of all Galileo Galilei gave the Northern Lights their name "The Aurora Borealis" which is a Latin name and which mean "Dawn of the north" But he couldn't tell the reason behind this phenomenon. But in 1896 a Norwegian scientist Kristian Birkeland explain the reason behind this why does it happen. Well as we know that....our sun is a gigantic massive ball of "Plasma", and every once in a while it kicks up a bit of a Solar storm., and the Sun generates its energy by nuclear fusion of "H"-nuclei into "He", using the process of nuclear fusion .the sun is able to turn small amount of matter into a enormous quantities of energy .It's how the sun has managed to keep producing energy for billions of years without running out of fuel. This plasma around the sun generates huge magnetic fields. The magnetic field is forced outwards into space at great speeds, taking extremely hot gases and charged particles with it, this is known as a "Solar Flare" and they can be witnessed on the sun's surface as a very bright spot followed by a cloud of gas .When a very large solar flair occurs containing a significantly huge amount of energy ,it referred to as a "Corona Mass Ejection", or "CME" for short.
The gas clouds produced by a CME can sometimes be larger then the sun itself, its doesn't stop charged particles ejected from the sun continue to travel outwards through space over enormous distances, After traveling through space for almost two days they will reach on earth ,this is known as the "Solar Wind" and it can be extremely dangerous ,if a CME were hit our planet earth it could the extinction of the all races on the earth including humans. now that a question is striking in your mind ,"why hasn't it".....well the solar wind regularly hit earth ,often ,but we have a defense system to protects us from the huge bombardment of the son, earth produce its own magnetic field because at the earth's core is a ball of solid iron ,the heat of this iron turns the surrounding outer core into flowing liquid iron the movement of this outer liquid core produces a magnetic fields, this protective barrier is called the "Earth's Magnetosphere" and it extends more then 600,000 kilometers (370,000 miles) from Earth which protect us from all sorts of HARSH Forces (not my friend Harsh vardhan because this disaster being is damn awesome ) that come from far away in space including solar flares. Most of the Sun's solar winds simply bounce off the earth's magnetosphere when it reaches us however the magnetosphere has two weak spots,at south pole and north pole thats why very small percentage of charged particles that come from the sun, and enter in earth's atmosphere via the two weak spots. When this happens the electrons in solar wind collide with oxygen & nitrogen in the atmosphere. During this, energy is transferred from the solar wind to nitrogen and oxygen atoms and raised it up from there normal state to exciting state ,when it's happen atom's electron move into an orbit further away from the nucleus. These newly exited atoms release their energy to return their normal state, atoms release their energy in the form of photons which we see as the light which we call Aurora. Different elements gives different color for example; Ionized nitrogen will produce Blue color, whereas neutral nitrogen molecules produce Purple-Red color and oxygen molecules cause the Green color and oxygen atoms cause the red color displays. simply... the color of emission line spectra depends on the chemical composition, and each type of atom produces its own unique color. and even, it is also produce sounds, there are generally two types of sound the first one is swishing sound that change with movement in that auroral display and the second one is crackling sound, like static electricity makes.
