Question

explain twinkling of star. Why does a planet not twinkle?

Answer 1

Unlike stars, planets don't twinkle. Stars are so distant that they appear as pinpoints of light in the night sky, even when viewed through a telescope. Because all the light is coming from a single point, its path is highly susceptible to atmospheric interference (i.e. their light is easily diffracted)

Answer 2

This is because of Atmospheric Refraction.

For Stars

• Stars are very far from us.(except sun)
• They appear point size to us
• When atmospheric refraction we appear to see the star in a different position.
• As the star gives many rays of light the stars appear to twinkle.

For Planets

• Planets are very close to us.
• They appear larger than stars
• Thus, they are a collection of points.
• Thus the refraction of light rays cancel out each other