What primarily causes a star to appear to flicker or twinkle?

Answer

The phenomenon is an optical effect caused by Earth's atmosphere.

The perceived twinkling is almost never due to erratic behavior from the star itself. Instead, it is caused by the Earth's atmosphere bending and distorting the light beam just before it reaches the observer.

What primarily causes a star to appear to flicker or twinkle?

#Videos

What Does It Mean When A Star Is Flickering? - Physics Frontier

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