Need some help in physics

[space stuff]

Stars appear to twinkle whereas, planets do not. Why ? I am a bit confused about it by reading from books. Can somebody explain it clearly ?

Edited February 22, 2012 by Sarthak Sahu

[swansont]

Stars appear to twinkle whereas, planets do not. Why ? I am a bit confused about it by reading from books. Can somebody explain it clearly ?

 

Do you understand the cause of the twinkling of the stars?

[space stuff]

Do you understand the cause of the twinkling of the stars?

 

Yes, I do. It is due to the refraction of starlight by the moving air pockets in the atmosphere.

But, what confuses me is that the stars are said be point sized objects.

[swansont]

Yes, I do. It is due to the refraction of starlight by the moving air pockets in the atmosphere.

But, what confuses me is that the stars are said be point sized objects.

 

That's because they are very, very far away. Light years away, even for the closest star, and most are orders of magnitude further away. Whereas planets are light-minutes away, so the angular size of a (naked-eye visible) planet is large compared to that of a star — they are bigger than the fluctuations in refraction caused by the turbulence in the atmosphere.

[space stuff]

That's because they are very, very far away. Light years away, even for the closest star, and most are orders of magnitude further away. Whereas planets are light-minutes away, so the angular size of a (naked-eye visible) planet is large compared to that of a star — they are bigger than the fluctuations in refraction caused by the turbulence in the atmosphere.

 

Thank you sir !

[rktpro]

Yes, I do. It is due to the refraction of starlight by the moving air pockets in the atmosphere.

 

An interesting point you must note here is that scintillation or twinkling is possible due to turbulence of atmosphere and continuous change in apparent position of the star. Also, the turbulence is the cause of change in amount of light entering the eye.