Question

Stars twinkle but planet do not twinkle because :

• A. stars emit their own light but planets receive light from the stars
• B. stars do not form a part of solar system
• C. stars form a point source of light while planets are considered as a collection of a large number of point sources of light
• D. during refraction of star light from the atmosphere, star light bends more towards the normal as compared to the planets

Answer 1

Answer: (C)

stars form a point source of light while planets are considered as a collection of a large number of point sources of light

As the light from a star enters the atmosphere, it hits gas molecules and scatters(reflection and interference).
Stars form a point source of light whiIe planets are considered as a collection of a large number of point sources of light.
Since the star is so far away, we only see a tiny beam of light from it. This beam gets scattered away from our eyes and then back into them almost like it is blinking on and off. It happens so fast that it just looks like it is twinkling.
(Planets are closer to us and send more light; if some of the light beams are scattered away, others still get through to us, so planets don't usually twinkle.)