Why Do Stars Sparkle?

When we look up at the night sky and see a beautiful array of stars, we can't help but notice that the stars appear to sparkle, or twinkle. But why does this happen?

Stars are actually suns which are very far away, and, like our sun, they are giving off a great deal of light. Because of the vast distances that separate the stars from the earth, the stars appear to us as tiny points of light. However, this light is distorted by moving air in the earth's atmosphere, and so the stars appear to sparkle. The light from the stars has to pass through several miles of the earth's atmosphere, and so the light is given a wobble, just like if you look in a swimming pool, the bottom of the pool appears to wobble becasue the light has been distorted, It is this distortion of light that makes the stars appear to sparkle or twinkle.

So the sparkle is to do with the earth's atmosphere, not the stars themselves. If you look at thestars through the Hubble telescope, which is out in space, they will not appear to sparkle.