Why do stars change colour when they twinkle?
Why do stars change their colour constantly every second? red-blue-red-blue..............
This is because of scintillation ("Twinkling") as the light passes through the atmosphere of the Earth. As the air moves in and out, the starlight is refracted, often different colors in different directions. Because of this "chromatic abberation," stars can appear to change colors when they are twinkling strongly.
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