Sun!

due to rotation and revolution system when we are infront of sun we can see the sun in day time and as are we in opposite side at night we can not see it.But other stars are always present in the sky .We can not see in day those due to heavy sunlight.

this is very simple because sun is so near to earth as compare to earth . the light emitting from sun that reaches to us is so large that we can't see the stars in day when sun shines .

The stars are also present in the day time but only sun is visible,the fact is they are near to our earth and so they are very bright.

Star are also seen in daylight but the distance is far off. Sun is very near to earth and hence we can observe the same.

Stars are very far from earth and sun is near, as stars are far from earth so they look smaller then sun too.

Sun is much nearer than other stars. We are in the solar system of which Sun is central point. The rays of Sun reach Earth and shine so bright that other stars that are far away fade. During night, Sun is seen on the other hemisphere of Earth and so other stars are visible.

The light from the sun, which is the closest star to the earth, is so intense during the day that it overpowers the light from all the rest of the stars.