When we look at the night sky, we often notice that some of the bright objects in it seem to flicker or change their brightness, while others remain steady and constant. The twinkling effect of stars is caused by atmospheric refraction. However, planets don’t twinkle like stars. In this article, we will explore why the planets don’t twinkle.
Planets are much closer to Earth than stars, which is the main reason why they don’t twinkle. The light from planets comes from a wider area and is less affected by atmospheric refraction. On the other hand, stars are very far away from us, so we see them as point sources of light. Any small change in their position or brightness can cause a noticeable twinkle.
Another reason why planets don’t twinkle is their size. Planets appear larger in size than stars, and they subtend a bigger angle at our eyes. This means that even if some parts of the planet’s image are distorted by air currents, the overall brightness and shape of the planet remain stable.
Moreover, planets are not point sources of light like stars. They reflect sunlight from their surfaces, which have different features and colors. This makes them look more like disks than points and reduces the twinkling effect.
In contrast, stars are smaller in size and emit light from their cores. As the light rays from stars pass through different layers of air with different densities and temperatures, they bend, causing the apparent position and brightness of the stars to change slightly from moment to moment.
To summarize, planets don’t twinkle because they are closer to Earth, larger in size, and reflect sunlight from their surfaces. Stars twinkle because they are far away from us, smaller in size, and emit light from their cores. While atmospheric refraction causes both stars and planets to shift their positions slightly, the effect is more noticeable for stars than for planets.