A question about stars

[ashenlight]

Hi all,

I was wondering, why do stars twinkle, while planets do not?

I have been thinking about this alot lately, and my guess is that stars are much further away from us than planets, so some of their light doesn't get to us? Or gets messed around by our planet's atmosphere?

Maybe because a star is just a point of light to us, when the light refracts in the atmosphere it appears to twinkle, whilst a planet, being a 'disk' of reflected light when we observe it in the night sky (as Saturn appears in Leo) isn't affected by this twinkling caused by the atmosphere, because it is bigger in the sky than the 'point' star, and the light isn't affected by the refracting? Hmm.

It seems such a simple question, but I am sure other people are wondering too, so I ask for all of us.

Amanda

[Doc]

Stars twinkle because of turbulence in the atmosphere of the Earth. As the atmosphere churns, the light from the star is refracted in different directions.

Planets do not twinkle the way stars do. In fact, this is a good way of figuring out if a particular object you see in the sky is a planet or a star. The reason is that stars are so far away that they are essentially points of light on the sky, while planets actually have finite size.

[Psychobilly]

why don't planets twinkle - Google Search

Google is my friend.... Possibly my one and only friend.....

[The Warthog]

Hi all,

I was wondering, why do stars twinkle, while planets do not?

Maybe because a star is just a point of light to us, when the light refracts in the atmosphere it appears to twinkle, whilst a planet, being a 'disk' of reflected light when we observe it in the night sky (as Saturn appears in Leo) isn't affected by this twinkling caused by the atmosphere, because it is bigger in the sky than the 'point' star, and the light isn't affected by the refracting? Hmm.

It seems such a simple question, but I am sure other people are wondering too, so I ask for all of us.

Amanda

You are right. That is exactly the reason. A planet is a disk, and therefore consists of infinite points of light. If you observe a planet on a night when the stars are twinkling, however, the surface of the planet will appear to be swimming in turbulence.