Why Do Stars Twinkle Class 10?

Stars twinkle because their light passes through different layers of the Earth’s atmosphere, and this bending of light causes a change in brightness and position, making them appear to twinkle. The stars are very far from Earth. The light from a star travels a long distance to reach us. Before entering our eyes, it passes through various layers of the Earth's atmosphere. These layers have different temperatures and densities.

How It Works:

• As light enters the atmosphere, it changes direction multiple times due to refraction.
• This continuous change in direction makes the light path slightly unstable.
• Because of this, the intensity (brightness) of the star’s light appears to change.

This effect is called:

Atmospheric Refraction – the bending of light when it passes through layers of air with varying densities.

Why Planets Do Not Twinkle:

• Planets are much closer than stars.
• They appear as tiny disks rather than point sources.
• The light from these disks averages out the twinkling effect.