When you look up at the sun (which you shouldn’t without some eye protection ;)), it’s light is constant. There is no twinkle in our star. However, when our night sky is littered with stars, they twinkle! Why do these stars twinkle?
Q: Why do stars twinkle?
A: The stars are not twinkling; actually most of them shine with a steady light. It’s the passing of their light through our atmosphere that causes them to twinkle!
Even though it looks like it, stars don’t blink. To us (observers on the surface of the Earth) the stars seem to change their brightness constantly. The movement of air in our atmosphere causes the “blinking” or “twinkling” effect. You’ve most likely experienced this air movement as turbulence on a recent airplane flight.
This air slightly bends the starlight as it passes through our atmosphere and into our eyes. However, some of the light reaches our eyes directly and some gets bent, making the stars twinkle.
Next time you’re out at night, take a look at the horizon and you’ll see more twinkling stars. This is because that light has to pass through a lot more of the atmosphere than a star straight above you. If you were on the International Space Station and you looked up, you would see no twinkling stars!
Watch our video on why the sky is blue and the sunset red to see more tricks light plays on our eyes!
Source: Scientific American