UPSC Mains 2024 GS1 Q15 — Physical Geography

• Definition and physical manifestation of auroras (The Light Show).
• Specific geographical locations (Southern vs Northern Hemispheres) and atmospheric layers involved.
• The Solar-Terrestrial mechanism: From Coronal Mass Ejections (CMEs) to Earth's magnetosphere.
• The role of ionization and specific atmospheric gases (Oxygen/Nitrogen) in creating different colors.

• Failing to mention the Thermosphere as the specific layer of the atmosphere where the phenomenon occurs.
• Ignoring the role of the Earth's magnetic field lines (Magnetosphere) in funneling particles toward the poles.
• Describing it as a purely 'weather' or 'climatic' event rather than a solar-plasma interaction.
• Omitting the reason for different colors (e.g., green from oxygen at lower altitudes vs red at higher).
• Spending too much time on the 'What' and not enough on the 'How' (the physics of the trigger).

Allocate 5 marks for the definition and differentiation between Australis and Borealis (approx. 75 words). Devote 10 marks to the 'trigger' mechanism, using a step-by-step process from solar flares to ionospheric collision, including a small schematic diagram if possible (approx. 175 words).