Do even torch lights twinkle in the sky?

[Astro.padma]

Dont ignore this as a hypothetical one, but really I have some doubt... suppose we made a very bright torch light and took it to Mars. Now assuming that the light is bright enough for me to observe it from Earth with the naked eye, would we see the light twinkling?

Is the twinkling only property of stars or anything else?

Um...am sorry if my questions are a bit silly but please try to answer them as I am really a beginner :)

 

[Nabeshin]

Yes the torch light would twinkle. The reason for the twinkling is disturbances in the Earth's atmosphere. I'm sure you're familiar with the wavy nature of things when you're looking through hot air, say above a highway or fire. This is the same principle that causes starlight to twinkle. Now, the reason that planets don't twinkle is because they are not points in the sky -- even though we can't really tell with our eyes, they're actually small disks. So, the same atmospheric disturbances which block out a star's light block out only a small fraction of the planet's disk -- we can't tell!

 

[Astro.padma]

Um... Why is the behaviour of torchlight similar to that of the star and not to that of the planet?

And planets don't twinkle because they are not point sized as they are at lesser distances than the stars. But in this case even our torch light is placed near the planet, right? Then why would it twinkle like stars?

 

[Nabeshin]

Sorry, I obviously didn't mean to imply that either the stars or the torch is a point. The thing is, the star is so far away that it is effectively a point source. Similarly, since a torch is much smaller, it is effectively a point source, even though it might be much closer.

The distance is not relevant in and of itself, it is the angular size that counts.

 

[Astro.padma]

Oh...ok Sir :) thank you :)