Why do the stars twinkle?
Stars are actually very large, but they are very far away so they look small. In fact, stars are so far away from Earth that we commonly refer to them as being “infinitely” far away, which results in their looking like a “point source” of light. The only reason that we see stars at all at such enormously large distances is that they are exceptionally bright. Starlight comes toward Earth along a path through space that produces very little change in the light. However, on Earth we see stars by looking through our planets atmosphere, which is a thin shell of gases surrounding our planet that provide gases for breathing and insulation from the intense cold and heat of space. Our atmosphere is thin compared to the long path that starlight takes through space, but it has a dramatic effect on a stars appearance.
Stars do not really twinkle, they just appear to twinkle when seen from the surface of Earth. The stars twinkle in the night sky because of the effects of our atmosphere. When starlight enters our atmosphere it is affected by winds in the atmosphere and by areas with different temperatures and densities. This causes the light from the star to twinkle when seen from the ground.
What you are seeing when you look at stars and they appear to ‘twinkle’ is the heat haze generated by the earth. The same way the road appears to shimmer in the desert. If you were to look at a star from outside the earths atmosphere it would not twinkle at all. It would have uninterupted light coming from it.
