Name the phenomenon of light is responsible for twinkling of stars. Why does it not cause planets to twinkle as well?

Answer

**Step-by-Step Solution:**

1. **Identify the Phenomenon Responsible for Twinkling of Stars:**
The twinkling of stars is primarily caused by the phenomenon of **atmospheric refraction**. As light from stars passes through different layers of the Earth's atmosphere, it bends due to variations in temperature and density of the air. This bending causes the light to change direction slightly, making the stars appear to flicker or twinkle.

2. **Explain Why Stars Twinkle:**
Stars are very far away from us and act as **point sources of light**. Because they are so distant, only a few light rays from each star reach our eyes. When atmospheric conditions change (like wind or temperature), the refractive index of the air changes, causing some light rays to bend more than others. This results in fluctuations in the brightness of the star as seen from Earth, leading to the twinkling effect.

3. **Discuss Why Planets Do Not Twinkle:**
In contrast to stars, planets are much closer to Earth. Although they also have light refracted by the atmosphere, they appear larger than stars due to their proximity. This means that a larger number of light rays from planets reach our eyes. Even if some light rays are bent due to atmospheric conditions, the overall brightness of the planets remains relatively constant because there are many rays contributing to their light. Therefore, the changes in brightness are not significant enough for us to perceive twinkling.

4. **Conclusion:**
In summary, the twinkling of stars is caused by atmospheric refraction, which affects the limited light rays from distant stars. Planets do not twinkle because they are closer and emit a greater number of light rays, making any variations in brightness imperceptible.

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