Question

why do not planet twinkling?

Answer 1

Planet do not twinkle because they are non luminescent bodies. Only luminescent celestial bodies ( stars)emit light continuously and this light when passes through the atmosphere of varying densities they seem to twinkle due to atmospheric multiple refraction.

Answer 2

Explanation:

Planets are much closer to the earth and are seen as extended sources. So, a planet may be considered as a collection of a large number of point-sized light sources. Although light coming from individual point-sized sources flickers but the total amount of light entering our eye from all the individual point-sized sources average out to be constant. Thereby, planets appear equally bright and there is no twinkling of planets.