Interstellar Gas & Dust, Densities & Temperatures

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Discussion Overview

The discussion centers around the relationship between density and temperature in various types of interstellar medium objects, including cold dark nebulae, diffuse nebulae, ionized gas, and plasma. Participants explore the complexities of defining heat and the behavior of atoms and molecules in these contexts.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks data on the correlation between density and temperature for different interstellar medium objects, noting the lack of clear information available online.
  • Another participant suggests that average temperatures and densities will vary significantly between plasma and atomic or molecular clouds.
  • There is mention of a temperature range from near absolute zero to around 8000 degrees Kelvin, highlighting the inconsistency in available data regarding density and temperature correlations.
  • A link to a NASA article is provided, which discusses extremely high temperatures in plasma but does not adequately address density information.
  • Participants express frustration over the lack of correlation between density and temperature in the literature, suggesting that relevant information is often missing or poorly reported.
  • One participant humorously suggests that acquiring a textbook may be necessary to find the desired information, while another acknowledges their own lack of expertise.

Areas of Agreement / Disagreement

Participants generally agree on the difficulty of finding comprehensive data that correlates density and temperature for the specified interstellar medium objects. However, there is no consensus on specific values or relationships, and multiple viewpoints regarding the availability of information are expressed.

Contextual Notes

Participants note limitations in the available literature, including vague answers and a lack of correlation between density and temperature data. There are also unresolved questions about the definitions and conditions under which these measurements apply.

treddie
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Howdie.
This question started from what was to be a "simple" analysis of heating the air in a room. So much for simplicity when you start to question what exactly is heat and what is happening to atoms and molecules. SOOOO...the question I have (which will have bearing on my INITIAL quest), is this. Does anyone have data for range of density vs. range of temperature for the following Interstellar Medium objects?
1. Cold, dark nebulae
2. Diffuse nebulae
3. Ionized gas
4. Plasma

In my web searches I get vague answers for densities and temperatures but never any rough correlation between the two.

Thanks for any responses!:smile:
 
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I don't know but if you mean average temperatures and densities then they will be very different for plasma vs atomic vs molecular clouds.
 
Last edited:
Yes, we're talking near zero deg K to something like 8000 deg K. It seems like all the material out there talks about densities or temperatures but rarely both as a correlation, and even then, the holes in their information are large enough to fit a galaxy through.
 
Yep...that's some hot stuff there in that link.

But notice that in the article they say that they can look at the density and temperature of such-and-such plasma, then proceed to give temperatures, yet for some reason brain-fart when it comes to reporting densities! Everywhere I go on the web, it's the same thing...no correlation.
 
the ministry of information not giving relevant and important information? really? I can't believe it. :-)

you may have to buy a textbook to get the information you want.

maybe if I knew what you hope to learn from this I could help you better. (not that I am an expert, of course)
 
I'm not an expert either (although I play one on TV).

It's time to add a new book to my collection anyway...I think there's one empty slot left.
 

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