Why are Auroras formed?

 A u r o r a

April 27, 2021

Hello, my dear astronomers!! I know you all love stargazing. And today I am going to introduce you to a much 'brighter' topic that mankind has marveled at for centuries. I am so sure that all of you must have heard the term 'AURORA.' Well, what exactly is an aurora? 

An aurora referred to as polar lights, northern lights, or southern lights, is a natural light display in the Earth's sky, predominantly seen in high-latitude regions. Then how is this captivating and mesmerizing light formed?

Every second, one million tons of matter is blasted from the sun at the velocity of one million miles per hour, and it's on a mission to collide with the Earth. This is the journey of Polar Lights. 

The protons and electrons create the northern lights which depart from the Sun's corona.😮😱 Don't worry its not our present time corona.😜(The corona is the outermost layer of the Sun's atmosphere and is one of the hottest regions.) Its intense heat causes the Sun's hydrogen and helium atoms to vibrate and shake off protons and electrons. Finally, these protons and electrons move too fast and group together to form plasma, (an electrically charged gas.) They travel away from the sun as a constant gale (strong wind) of plasma, known as the SOLAR WIND. Then why is this solar wind so dangerous? It is because Solar Wind consists of super hot charged particles which are fatal.

However, the Earth prevents the solar wind from barging straight into the planet by setting up its magnetic field. The earth's magnetic field acts like a shield and protects us.  Its field lines appear to emerge from the south pole and merge into the north pole.    

Now, when the charged particles hit our magnetic field, most of them get deflected however, some of them flow along the earth's magnetic field lines to the poles and reach our upper atmosphere. Here the electrons and protons collide with the oxygen and nitrogen atoms giving their energy to the earth's neutral oxygen and nitrogen atoms. When these atoms are contacted by the particles, they get excited and emit photons. Photons are small bursts of energy in the form of light.  

The colors that appear in the sky depend on the wavelength of the atom's photon. Excited oxygen atoms are responsible for the green and red colors, whereas excited nitrogen atoms produce blue and deep red hues. The collection of these interactions is what creates the northern lights. I wonder why these northern and southern lights are visible only at night? 

This is because the polar lights are best seen on clear nights in regions close to the magnetic north and south poles. Nighttime is ideal because the Aurora is much dimmer than sunlight and cannot be seen in the daytime. Read up on the sun's energy patterns, specifically sunspots, and solar flares, as these will be good guides for predicting the auroras. 

Aaah!! These stunning pictures. I wish if Aurora could occur in Ahmedabad.😂😂