Question

why does star seem twinkle at night

Answer 1

Stars do not really twinkle, they just appear to twinkle when seen from the surface of Earth. The stars twinkle in the night sky because of the effects of our atmosphere. When starlight enters our atmosphere it is affected by winds in the atmosphere and by areas with different temperatures and densities.

Answer 2

Twinkling to star is due to the atmospheric atmospheric atmospheric refraction of sunlight the star on the crar night at a appear to the sky but their not twinkling.
The light of stars when enters into earth atmosphere undergo refraction continously before it reaches the earth due to which the amount of light and appear in position of our star reaches to our eyes.
So the star appear twinkle so we say that star appear the brightener and fine point.