What happens to the pinpoint beam of light from a distant star as it passes through turbulent atmospheric layers?

Answer

The light is slightly refracted, or bent, in random directions many times per second.

The atmospheric irregularities function as tiny lenses, causing the continuous, minuscule shifting of the star's light path, which is observed as twinkling.

What happens to the pinpoint beam of light from a distant star as it passes through turbulent atmospheric layers?
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