Question

why star is twinkle bt not sun and other planet?

Answer 1

Stars are self emitting Suns and therefore twinkle but sun not because Sun is also a star but a big star in Milky way while planets do not emit their own light. Stars which we see at night are sun of their own galaxy.

Answer 2

stars twinkle but not sun and planet because stars are very distant (very far) from earth so the light emitted by them reaches us in fractions and a lot more time. moreover the time between the succesive recieval of light particles from states is more hence they twinkle........