What is an aurora, and what are the processes that lead to its formation? (10M, 150 words) [GS-2: Geography]

Introduction

• Auroras are spectacular natural light displays that appear as bright, swirling curtains in the night sky, often in various colors such as blue, red, yellow, green, and orange.
• These lights predominantly occur near the poles of both the northern and southern hemispheres throughout the year but can occasionally extend to lower latitudes.
• The northern lights are referred to as aurora borealis, while the southern lights are known as aurora australis.

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Why do auroras occur?

• Auroras result from solar activity. The Sun emits a constant stream of charged particles, primarily electrons and protons, and magnetic fields known as the solar wind. As the solar wind approaches Earth, it is deflected by the planet’s magnetic field, acting as a protective barrier.
• Some charged particles get trapped in the magnetic field and travel along magnetic field lines near the north and south poles into the Earth’s upper atmosphere.
• These particles interact with atmospheric gases, producing small flashes of light that illuminate the night sky. When solar wind particles collide with oxygen, they produce green light, while interactions with nitrogen generate blue and purple hues.
• During periods of intense solar activity, such as solar flares and coronal mass ejections (CMEs), the solar wind becomes particularly strong, causing auroras to extend to mid-latitudes. These bursts of energy in the solar wind can lead to geomagnetic storms, transient perturbations of the Earth’s magnetic field, making auroras visible in mid-latitudes.
• For instance, during significant solar storms, auroras have been observed as far south as latitudes comparable to the northern regions of India.

Conclusion

• According to NASA, solar storms occur when the Sun ejects more solar flares or explosions from its surface, dispersing high-energy particles.
• These flares release ionized radiation, which, upon interacting with Earth’s atmosphere, create magnetic fields that result in the stunning phenomenon of auroras.