Question

why do stats twinkle.

Answer 1

due refraction of light because our earth contains layers in atmosphere which are different in density each time the ray bends towards the normal because light enters from rare medium to denser medium

Answer 2

Stars twinkle due to atmospheric refraction of starlight. As the stars are very far away they behave as almost point source of light. As on account of atmospheric refraction the path rays of light coming from the stars goes on varying slightly, the apparent position of the star fluctuatesvand the amount of starlight entering the eye flickers. So that's why stars twinkle.



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