Stars twinkle, planets do not. Planets appear to shine unwaveringly as a result of the distance between the planets. Even with high-resolution telescopes, stars look like mere dots, seeming to twinkle due to refraction when passing through the earth’s atmosphere. Planets, on the other hand, are much closer to the earth which appear as small discs through a telescope. Refraction is also observed in the case of planets when light from them enters the earth’s surface, but this light from both terminals of the planet repel away from each other in the opposite direction, nullifying their effect. Hence, they appear steady.

The Planets Do Not Twinkle

The twinkling of stars is a phenomenon that many of us are familiar with. When we look up at the night sky, we often see stars flickering and shimmering. However, if you observe the planets in the night sky, you may notice that they do not twinkle like the stars do. This is because the planets are much closer to us than the stars, and their light behaves differently as it travels through Earth's atmosphere.

Reasons why the planets do not twinkle:

1. Larger Apparent Size:
One reason why planets do not twinkle is because they appear larger in the night sky compared to stars. The planets in our solar system are relatively close to Earth, which means they have a larger apparent size when observed from our planet. This larger size helps to average out the effects of atmospheric turbulence, resulting in a more stable and steady appearance.

2. Multiple Light Sources:
Another factor that contributes to the lack of twinkle in planets is the presence of multiple light sources. Stars are essentially point sources of light, and as their light passes through Earth's atmosphere, it gets refracted and scattered, causing the twinkling effect. However, planets reflect the light from our Sun, which is a larger and more extended light source. The multiple light sources create a more uniform and constant illumination, reducing the twinkling effect.

3. Atmospheric Disturbances:
The Earth's atmosphere is not completely still; it contains various layers and pockets of air with different densities and temperatures. These variations in the atmosphere cause the light from stars to bend and scatter, resulting in the twinkling effect. However, since planets are much closer to Earth, their light has to pass through a smaller portion of the atmosphere, reducing the impact of atmospheric disturbances. As a result, the planets appear more steady and do not twinkle.

4. Angular Size:
The angular size of an object refers to its apparent size as observed from a specific location. Planets have a larger angular size compared to stars, which means they cover a larger portion of our field of view. This larger angular size helps to reduce the apparent fluctuations in brightness, resulting in a more stable and constant appearance.

Conclusion:
In summary, the planets do not twinkle because they appear larger in the night sky, reflect light from a larger and more extended source, pass through a smaller portion of Earth's atmosphere, and have a larger angular size. These factors contribute to a more stable and constant appearance of the planets, distinguishing them from the twinkling stars.