UPSC Prelims 2025 Q33: Geography – Astronomy & Earth - Sun System
Consider the following statements:
Statement I: Scientific studies suggest that a shift is taking place in the Earth's rotation and axis.
Statement II: Solar flares and associated coronal mass ejections bombarded the Earth's
outermost atmosphere with tremendous amount of energy.
Statement III: As the Earth's polar ice melts, the water tends to move towards the equator.
Which one of the following is correct in respect of the above statements?
- (a) Both Statement II and Statement III are correct and both of them explain Statement I
- (b) Both Statement II and Statement III are correct but only one of them explains Statement I
- (c) Only one of the Statements II and III is correct and that explains Statement I
- (d) Neither Statement II nor Statement III is correct
Answer: (b) Both Statement II and Statement III are correct but only one of them explains Statement I
Explanation
Shift in the Earth's rotation and axis
| Statement | Verdict | Fact |
|---|---|---|
| I. Scientific studies suggest that a shift is taking place in the Earth's rotation and axis | Correct | Studies show polar motion and slightly longer days |
| II. Solar flares and coronal mass ejections bombarded the Earth's outermost atmosphere with tremendous energy | Correct | A true fact (for example, the storms of May 2024), but it does not shift the axis |
| III. As the Earth's polar ice melts, the water tends to move towards the equator | Correct | Mass moves from the poles to the equator, which changes the spin; this explains Statement I |
Why moving water matters:
| Idea | Detail |
|---|---|
| Like a skater | Spreading mass away from the axis slows the spin |
| Other causes | Heavy groundwater pumping also shifts the pole |
Both II and III are correct, but only Statement III explains Statement I.
Answer: (b) Both Statement II and Statement III are correct but only one of them explains Statement I.
Why each option is right or wrong
- (a) Incorrect. Solar flares do not explain the shift in the Earth's axis.
- (b) CORRECT. Both are true, but only the movement of meltwater explains Statement I.
- (c) Incorrect. Both Statements II and III are correct, not just one.
- (d) Incorrect. Both Statements II and III are correct.
Key point
Melting polar ice moves mass towards the equator, shifting the Earth's axis and lengthening days; solar flares are real but unrelated to this shift.
Remember
Ice melt moves water to the equator and shifts the axis.
Common mistakes
- Marking a true statement as the explanation without checking the link.
- Thinking solar flares can change the Earth's rotation.
- Forgetting groundwater depletion as another cause of polar shift.
Exam tip
Two tests for each statement: is it true, and does it explain? Statement II passes only the first.
Sources
- NASA Jet Propulsion Laboratory — Climate change is altering Earth's rotation (2024)
- NCERT Class XI — Fundamentals of Physical Geography, Ch 2 (The Origin and Evolution of the Earth)