Long vs Short light wavelength absorption

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Discussion Overview

The discussion centers around the absorption and scattering of light by dust clouds in astrophysics, specifically focusing on why shorter wavelengths are more significantly affected than longer wavelengths. The scope includes conceptual understanding and theoretical implications in astrophysics.

Discussion Character

  • Conceptual clarification
  • Exploratory

Main Points Raised

  • One participant expresses confusion regarding the statement that shorter wavelengths are affected more than longer wavelengths when passing through a dust cloud.
  • Another participant proposes that shorter wavelengths correspond to higher energy particles, leading to more collisions with dust cloud particles, suggesting a possible explanation.
  • A later post indicates that the original poster found an explanation in the same book, comparing the behavior of light wavelengths to ripples on a pond, where larger ripples are less disturbed than smaller ones.
  • A participant adds a reference to Rayleigh scattering, linking it to the phenomenon of a blue sky, implying a connection to the discussion on light scattering.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the explanation for the differential effects of light wavelengths, with some proposing ideas while others reference external sources without resolving the initial confusion.

Contextual Notes

The discussion includes references to specific pages in a textbook that provide explanations, but the assumptions and detailed mechanisms behind the scattering and absorption processes remain partially unexplored.

jumphigh
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Hi all

I was reading through an astrophysics book{1} and there I came across this sentence:

" A dust cloud can either scatter or absorb light that passes through it. Since shorter wavelengths are affected more significantly than longer ones, a star lying behind the cloud appears reddened to an observer."

I do not understand why shorter wavelengths are affected more than longer wavelengths. I may be missing some basic relation but I can't figure it out right now.

Thanks

{1}: "An introduction to modern astrophysics", R. W. Carroll, D. A. Ostlie, page 439
 
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hmm...I think it would be sth like this:

shorter wavelength -> higher energy particles -> more collision with dust cloud particles

is that correct?
 
well i found the answer before anybody answers me, i thought i should post it for future ref

same book, page 440 explains in detail about how shorter wavelength can be greater affected by the environment than long wavelengths.

As an example, the large ripples on a pond can travel along without being disturbed by the leafs and dust grains on the surface of the pond whereas small ripples get distorted.

I hope this post will be useful for someone in future.
 

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