Explain why the planets do not twinkle.

The planets are much closer to the earth and are thus seen as extended sources. If we consider a planet as a collection of a large number of point-sizes sources of light, the total variation in the amount of light entering our eye from all the individual, point-sizes sources will average out to zero, thereby' nullifying the twinkling effect.

The planets are much closer to the earth, and are thus seen as extended sources. If we consider a plant as a collection of large number of point sized sources of light, the total variation in the amount of light entering our eye from all the individual point-sized sources will average out to zero, thereby nullifying the twinkling effect.