The twinkling of star is due to

The twinkling of stars is due to atmospheric :

The twinkling of stars is due to atmospheric :

Assertion :- The twinkling of stars is due to the fact that refractive index of the earth's atmosphere fluctuates. Reason :- In cold countries, the phenomenon of looming (i.e ship appears in the sky) takes place, because refractive index of air decreases with height.