alleryWhy do planets NOT twinkle though stars do?
APlanets are too dim in the standard view
BPlanets do not emit light
CPlanets are bigger than the wave-front fluctuations
DPlanets are inside our atmosphere
Answer & Solution
Correct answer: C. Planets are bigger than the wave-front fluctuations
1. Stars are essentially point sources because of their huge distance.
2. Atmospheric refraction shifts the tiny image of a star at random.
3. Planets are closer and appear as extended discs.
4. Random shifts across an extended disc average out.
5. So a planet's overall brightness stays steady, while a star flickers.
6. Hence planets do not twinkle.
_Source: syllabus Science Ch 11 'Human Eye and the Colourful World'_
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