Question

why does all the stars revolve around the pole star? and why is the pole star stationary?

Answer 1

We know that the earth rotates about an axis which itself remains stationary (for a small interval of time at least). This axis is basically defined the north and south line of the earth. Now the pole star (polaris) is placed quite close to the celestial north of the earth. This means that the pole star does not move with resect to the earth unlike all the other stars do (the same would be true for any star placed due south). Now, as pole star remains fixed and in line with the rotational axis all other stars seem to rotate around it in closed circles.