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Why don't the planets twinkle but stars do?
APlanets are inside Earth's atmosphere (option)
BStars have their own atmosphere
CPlanets are extended sources; stars are point sources, so atmospheric flicker only averages out for planets
DStars are coloured
Answer & Solution
Correct answer: C. Planets are extended sources; stars are point sources, so atmospheric flicker only averages out for planets
1. Stars are so distant that they appear as a single point.
2. A point source is fully affected by any atmospheric flicker in its narrow ray.
3. Planets, being closer, are disc-like sources; fluctuations from many points cancel out.
_Source: NCERT Class 10 Science, Ch 10 "The Human Eye and the Colourful World", §10.5_
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