← All questionsGS1 · 2024 · Geography ·Aurora Borealis and Aurora Australis
QUESTION 15
GS1
15 marks

What are aurora australis and aurora borealis? How are these triggered?

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11 min
250 words
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What the examiner wants

Explain what the northern and southern lights are and how they are triggered.

ExplainMake clear how and why it happens: causes, process, and an example for each point.

Demand-wise check

  1. 1Definition: natural light displays in the polar skies, northern (borealis) and southern (australis)≈65 words
  2. 2Trigger: charged particles from the solar wind and coronal mass ejections, guided by Earth's magnetic field to the poles, colliding with oxygen and nitrogen in the upper atmosphere≈65 words
  3. 3Colours and why they are seen more during solar maximum (e.g. May 2024 auroras seen from Ladakh)≈65 words

Open in about 30 words and close in about 30.

Answer plan

DefinitionSolar wind and magnetosphereCollisions and coloursLink to solar activityExampleConclusion

Where marks usually go

  • Saying auroras are caused by reflection of sunlight from ice
  • Not explaining the role of Earth's magnetic field

Draw this

  • Diagram: Sun → solar wind → Earth's magnetic field lines → auroral oval

Value addition

  • ExampleDuring the strong geomagnetic storm of May 2024, auroras were photographed from Hanle in Ladakh.Indian Institute of Astrophysics, Hanle observatory
  • FactGreen auroras come mostly from oxygen at about 100–300 km height; red from high-altitude oxygen and blue/purple from nitrogen.NASA

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