Why Do Stars Twinkle?

"Twinkle, twinkle, little star." We all know how the song goes, but do we really know what the song is talking about? Do the stars really twinkle?

Scintillation is the technical term for the phenomenon we know as "twinkling". True twinkling is the oscillation of light from its source that makes it appear to be shaking or shifting. Stars are burning orbs of gas that send light from light years away through space to our humble planet. Once it makes it to our planet, it must pass through the atmosphere as well. As it passes through the atmosphere, it goes through layers of air turbulence that distort our image of the light from the stars. This is what results in what we know as the twinkle of the stars.

This explains how on certain nights the stars seem still, while on others they twinkle. Depending on the air currents of the particular night, you may have either effect. Either way, you are seeing the same light, but one with more distortion than the other. Refraction also plays into this as well, which is why the tiny stars always seem to twinkle. The longer the distance from earth, the less light will get here. The less light, the easier to distort.

This brings us to another interesting point, planets almost never twinkle. This is because they are so much closer to the earth than stars are, therefore; it take immense amounts of turbulence to distort their light.

I am almost sad to publish this post. I hate ruining children's songs for people. Oh well, it's for science, I suppose.