Planets do not twinkle like stars because they are much closer to Earth and appear as tiny disks rather than point sources of light. The light from a planet covers a larger area in the sky, so the effects of atmospheric turbulence are averaged out over the planet’s apparent size. While some light rays might be refracted, others remain steady, making the overall light appear constant. This results in a steady shine rather than a twinkling effect.

Let’s discuss in detail

Understanding Why Planets Don’t Twinkle

Planets: Closer and Apparent Size
Unlike stars, planets in our solar system are much closer to Earth. This proximity means that they appear in the sky not as point sources of light, like distant stars, but as tiny disks.

The Effect of Atmospheric Turbulence on Planets

When light from planets passes through Earth’s atmosphere, it encounters the same turbulence that causes stars to twinkle. However, the effect on planets is different due to their apparent size in the sky.

Averaging Out the Atmospheric Effects

The larger apparent size of planets means that the light reaching us covers a broader area in the sky. As a result, the atmospheric turbulence affects different parts of the light differently. Some rays might be refracted, but others remain steady.

The Steady Shine of Planets

This averaging effect of the different light rays means that the overall light from a planet tends to remain constant in our view. While individual rays of light are still impacted by atmospheric changes, their collective impact averages out, resulting in a steady shine.

Contrast with Stars

In contrast, stars are so far away that they appear as mere points of light. The atmospheric turbulence affects all the light from a star in the same way, leading to the noticeable twinkling effect.

Download App for Class 10

Planetary Stability in the Night Sky
Therefore, the lack of twinkling in planets can be attributed to their relative proximity to Earth and their larger apparent size, which allows the effects of atmospheric turbulence to be averaged out, presenting a steady light to observers on Earth.

Discuss this question in detail or visit to Class 10 Science Chapter 10 for all questions.
Questions of 10th Science Chapter 10 in Detail

What is meant by power of accommodation of the eye?
A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision?
What is the far point and near point of the human eye with normal vision?
A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?
A person needs a lens of power –5.5 dioptres for correcting his distant vision. For correcting his near vision he needs a lens of power +1.5 dioptre. What is the focal length of the lens required for correcting (i) distant vision, and (ii) near vision?
The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the problem?
Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropic eye is 1 m. What is the power of the lens required to correct this defect?
Why is a normal eye not able to see clearly the objects placed closer than 25 cm?
What happens to the image distance in the eye when we increase the distance of an object from the eye?
Why do stars twinkle?
Explain why the planets do not twinkle?
Why does the sky appear dark instead of blue to an astronaut?