Stars twinkle due to the Earth’s atmosphere. As light from a star travels through the vacuum of space and enters our atmosphere, it encounters varying layers of air with different temperatures and densities. These layers cause the light to refract, or bend, in different directions. This refraction varies constantly due to atmospheric turbulence, making the star’s light appear to flicker or ‘twinkle’ when observed from the ground.

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Unravelling the Mystery of Twinkling Stars

The Journey of Starlight: Stars emit light that travels vast distances across the vacuum of space. This journey is straightforward until the light reaches the Earth’s atmosphere, where the twinkling phenomenon begins.

Entering the Earth’s Atmosphere

Upon entering the Earth’s atmosphere, starlight encounters layers of air with varying temperatures and densities. These atmospheric variations are primarily due to factors like altitude, geographical location, and weather conditions.

The Effect of Atmospheric Turbulence

The differing air densities and temperatures cause atmospheric turbulence. This turbulence bends or refracts the light rays from the star as they pass through the atmosphere, a process known as atmospheric refraction.

Constantly Changing Refraction

The refraction of starlight is not constant but changes rapidly due to the ever-shifting nature of the Earth’s atmosphere. These fluctuations result in the light path of the star altering continuously as it travels to the observer’s eye.

Visual Perception of Twinkling

To the observer on the ground, these variations in refraction make the star’s light appear to change in brightness and position. This perceived flickering or ‘twinkling’ is more pronounced for stars near the horizon, as their light passes through more atmospheric layers.

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The Atmospheric Influence
Thus, the twinkling of stars is a result of atmospheric turbulence affecting the path of starlight. This natural phenomenon highlights the complex interaction between celestial light and the Earth’s atmospheric conditions.

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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?