Twinkling of stars is primarily due to the atmospheric

[amp_mcq option1=”refraction” option2=”reflection” option3=”polarization” option4=”dispersion” correct=”option1″]

This question was previously asked in

UPSC NDA-2 – 2021

The correct answer is A) refraction.

Twinkling of stars is caused by atmospheric refraction. As starlight passes through different layers of the Earth’s atmosphere with varying densities and temperatures, it undergoes repeated refraction in random directions, causing the apparent position and brightness of the star to fluctuate.

Planets, being much closer than stars, appear as extended sources rather than point sources. The total amount of light entering the eye from a planet remains relatively constant despite atmospheric refraction, which is why planets do not appear to twinkle.

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