Single correct option
The twinkling of stars at night is caused by
- A. reflection from the Moon
- B. atmospheric refraction of starlight
- C. dispersion by the stars
- D. absorption by the ozone layer
Show answer and solution
Answer: (B) atmospheric refraction of starlight
Starlight passes through layers of the atmosphere whose density, and therefore refractive index, changes continuously and unsteadily. The apparent position and the amount of light reaching the eye keep fluctuating, producing twinkling. Planets are closer and appear as extended sources, so their fluctuations average out and they do not twinkle.
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