Detecting Cosmic Dust: The Challenges and Solutions

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Discussion Overview

The discussion revolves around the observation and verification of cosmic dust, exploring various methods and challenges associated with detecting it. Participants address both theoretical and observational aspects of cosmic dust in the context of astrophysics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant suggests that light from a known source passing through cosmic dust gets scattered, resulting in observable differences that can indicate the dust's molecular composition and density.
  • Another participant notes that visual observation of the Milky Way can reveal cosmic dust as it blocks light, creating dark dust lanes.
  • A claim is made that taking the spectrum of a star, with light passing through intervening dust, will show absorption and emission lines in the spectrum.
  • It is mentioned that cosmic dust differs from interstellar gas in that it does not produce absorption or emission lines, instead causing scattering and extinction of light, complicating astrophysical observations.
  • A practical observation method is described, involving viewing zodiacal light and gegenschein in a very dark location after allowing for eye adaptation.

Areas of Agreement / Disagreement

Participants express differing views on the characteristics of cosmic dust, particularly regarding its spectral properties compared to interstellar gas. There is no consensus on the best methods for observing cosmic dust, and the discussion remains unresolved.

Contextual Notes

Some claims about the spectral properties of cosmic dust and its comparison to interstellar gas may depend on specific definitions and assumptions that are not fully explored in the discussion.

tosv
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What kind of observation can be made to verify the existence of cosmic dust (space dust)?
 
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As I understand it: as the light from a known source (measured and steady luminocity and known wavelength) behind the dust passes through the dust, this light gets scattered. The light that then reaches the observer is different (color and length). Record these differences and you can determine the dust's molecular make-up and density.
 
Simply looking up at the milky way at night in a dark area will show you dust, as it blocks light from the rest of the galaxy from reaching us, creating dark dust lanes.
 
If you take the spectrum of a star and that light passes through dust between the star and us, it will show up in the spectrum as absorption and emission lines.
 
Unlike interstellar gas, cosmic dust does not have absorption or emission lines. It causes scattering and extinction of light emitted by more distant sources making it a real PITA to astrophysicists.
 
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Go to a very, very dark place (hard to find, you have to make a special effort and go far from highways, cities, and towns on a clear moonless night), wait for your eyes to fully dark-adapt (might take half an hour or more), and look up - you can see dust within our solar system as zodiacal light and gegenschein.
 
Chronos said:
Unlike interstellar gas, cosmic dust does not have absorption or emission lines. It causes scattering and extinction of light emitted by more distant sources making it a real PITA to astrophysicists.

Ahh, I figured so. :redface:
 

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