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This blog is an exciting new venture of the NSS of IIT Madras to create a magazine, which would cover topics in the realm of Sciences and Social Sciences, an aid for the students of classes VIII-XII. Our vision is to complement the student's academics with creative, coherent and concise inputs while creating an awareness about socio-political issues.

Aurora Lights



The term “Aurora” basically refers to a natural light at very high altitudes in the sky. The aurora borealis (the Northern Lights) and the aurora australis (the Southern Lights) have always fascinated mankind, and people even travel thousands of miles just to see the brilliant light shows in the earth's atmosphere. The auroras, both surrounding the north magnetic pole (aurora borealis) and south magnetic pole (aurora australis) occur when highly charged electrons from the solar wind interact with elements in the earth's atmosphere.

               Solar wind contains equal number of proton and electrons along with heavier ions. It blows continuously from the surface of the sun at a speed about 400km/hr. These winds scatter these ions in the solar system also towards the earth.

Earth is a gigantic magnet. It is approximately the field of a magnetic dipole tilted at an angle of 11 degrees with respect to the rotational axis—as if there were a bar magnet placed at that angle at the centre of the Earth. However, unlike the field of a bar magnet, Earth's field changes over time because it is really generated by the motion of molten iron alloys in the Earth's outer core (the geodynamo). The Magnetic North Pole wanders, fortunately slowly enough that the compass is useful for navigation                         


 This magnetic field around the earth is acts as a shield against the harmful solar winds. The charged particles in solar winds may lead to severe damage to telecommunication network. These particles would strip away the ozone layer, which protects the Earth from harmful ultraviolet rays. Calculations of the loss of carbon dioxide from the atmosphere of Mars, resulting from scavenging of ions by the solar wind, are consistent with a near-total loss of its atmosphere since the magnetic field of Mars turned off.
The charged particles when travel in space with great velocity generates magnetic field which is influenced by earth’s magnetic field. Hence they are driven by the magnetic field of the earth towards the poles.
                                                                                                                                     


These charged particles enter the ionospheres at the poles. In the ionosphere, the speeding electrons collide violently with gas atoms. This gives the gas atoms energy, which causes them to release both light and more electrons. In this way, the gases of the ionosphere glow and conduct flowing electric currents into and out of the polar region. The electrons flowing back out don't have as much energy as the incoming one hence the remaining goes to aurora.


-Article done by Akshay Nemade

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