Why stars flicker whereas planets shine steadily?

Light coming from both stars as well as planets passes through the layers of air of varying density as it penetrates Earth’s atmosphere. But the size of stars and planets as seen by us is not the same. Stars are gigantic but extremely distant so they appear like tiny dots. When the rays of their light refract and deviate in the atmosphere they appear to move out of the dot making the star also move or quiver or twinkle.
Similarly, the rays of light coming from planets also refract and deviate in the atmosphere. But planets are nearer. Therefore, they are visible to us not as tiny dots but rather as discs. Although rays of light coming from the planets also refract and deviate in the atmosphere they remain within the confines of the respective discs so that the refraction is not visible to us in the background of the bright disc of planet. Hence, the light of the planets appears as a steady glow and we do not see the planets doing a break-dance like the stars.
More reading:
Star (Wikipedia)
Planet (Wikipedia)
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