Why do stars twinkle?
A lot of people have seen the twinkling stars in the night sky. The reason that causes this is in the air and movement inhomogeneity. At the horizon the twinkling increases. Only this pattern says that the star twinkling depends on the atmosphere. In the picture you can see that the longer the beam, the smaller is the angle between the beam and the horizon plane. The star twinkling is due to the point that there are small constant flows and curls active in the air. The light gets bent in different ways in such air environment; it is also affected by the time.
The color of the stars also changes due to the scintillation. The thing is that the starlight, as well as the sunlight consists of different beams, which are bent in different ways because of the atmosphere. The blue beams fall down a bigger deflection than the red ones. The interesting fact is that everybody can observe the same star at the same time and still perceive different color of it. It develops that the “instantaneous” star color is different for the right eye and left eye of the same person.
read more: http://science-all.com/stars.html