Why do stars twinkle (or appear to slightly flicker)?

Question

Why do stars twinkle (or appear to slightly flicker)?

Answer 1

because they are balls are gas, I think

Answer 2

The actual size of the star is much smaller than our eyes can resolve.  Such a small source of light is called a virtual point source.  The light from a virtual point source possesses a characteristic called partial coherence.

Light that is partially coherent has the capability of causing interference with the light rays.  With interference the light rays may reinforce each other and get brighter or they may cancel each other out and get darker.

When you look at a star you are looking through an atmosphere that possesses minute variations of refraction and these changes cause the star to cancel and reinforce the light rays in a random fashion.  That random redirection of the rays causes the star to appear to twinkle.

Answer 3

It's because of the atmospheric movement. If you were watching the stars from space, you'd never see them "flicker".

Answer 4

Because of the Earth's atmosphere!

Answer 5

Space is full of gaseous particles flying around everywhere.  As these particles pass in front of the stars, they make the star "twinkle" and "flicker"  

Also, just some extra information.

When you go outside and look at a star, you are actually looking at the past version of the star.  What does that mean?  It means that light from the star takes thousands of years to travel all across space to Earth.   Because Earth is millions and billions of light years away from stars.

Answer 6

Stars "twinkle" because of distortion of the light as it passes through the Earth's atmosphere.  The light from a star is so dim and of such a small size that the distortion caused by the atmosphere is much more apparent than for a larger appearing object like the moon.  If you could look at stars from outside the Earth's atmosphere, you would not see any twinkling or flickering.

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