Would a non radiative atmosphere be isothermal?

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Discussion Overview

The discussion revolves around the concept of whether a non-radiative atmosphere would be isothermal as a function of height. Participants explore the implications of kinetic theory, gravity, and the effects of thermal dynamics in the absence of radiative processes.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants suggest that many physicists have considered the idea of a non-radiative atmosphere being isothermal, questioning its physical reality.
  • There is a discussion about the implications of kinetic theory and gas laws, with some participants expressing skepticism about the assumptions underlying these theories.
  • One participant questions the meaning of "isothermal as a function of height," seeking clarification on whether it refers to horizontal temperature uniformity at each height.
  • Another participant asserts that without radiative processes, the vertical temperature profile would likely be isothermal, but expresses discomfort with this assumption in the context of gravity.
  • Concerns are raised about the impact of Coriolis forces on atmospheric circulation, suggesting that these forces might create vertical movements despite the lack of radiative heating and cooling.
  • One participant argues that in the absence of heat flow, the properties of the Maxwell distribution would support the assumption of isothermal conditions at higher altitudes, despite fewer molecules being present.
  • There are requests for referenced sources to support claims made by participants, indicating a desire for substantiation of the arguments presented.

Areas of Agreement / Disagreement

Participants express differing views on the assumptions surrounding isothermal conditions in a non-radiative atmosphere. There is no consensus on the validity of these assumptions or the implications of kinetic theory in this context.

Contextual Notes

Some assumptions regarding the behavior of particles in a gravitational field and the effects of Coriolis forces remain unresolved, with participants questioning the adequacy of existing models and seeking further clarification.

Geoffw
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Many credited physicists have entertained the notion of a non radiative atmosphere being isothermal as a function of height.

But is this a physical reality?

Many physicists accept the macroscopic conclusions of kinetic theory, the gas laws. Statistical mechanics. Experimentally verifiable results from a set of provably reliable assumptions.

So what is wrong with these assumptions and their inevitable conclusions;

"Particles are small and spend most of their time between collisions. They have mass, and therefore feel gravity."

The inclusion of the latter in the frame of the former requires that 'information' about gravity is invested in the very framework of collisional energy transfer.

This is supported by data.

So what, despite supporting data, is wrong with kinetic theory. Why is it not supported by the scientific community?
 
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What do you mean by "isothermal as a function of height"? Do you mean that the temperature is (horizontally) isothermal at each height?
 
olivermsun said:
What do you mean by "isothermal as a function of height"? Do you mean that the temperature is (horizontally) isothermal at each height?

No, without the ability to radiate, it is often accepted that the vertical profile would be isothermal. Under those circumstances the atmosphere would be isotropic within its volume.

I find this an unacceptable asssumption in a gravity field.

What do you think?
 
@Geoffw
What I think: please supply a source (refereed ) article for your comments. I cannot separate what you think from what you are basing your statements on.
Thanks!
 
The lack of solar radiation heating during the day and cooling by radiation at night, would reduce thermal density changes and therefore vertical movement of the atmosphere.

But what about the Coriolis forces that break the atmosphere into slowly rotating high pressure systems with many smaller counter-rotating low pressure eddies between them? Will that not generate some vertical circulation?
 
Geoffw said:
No, without the ability to radiate, it is often accepted that the vertical profile would be isothermal. Under those circumstances the atmosphere would be isotropic within its volume.

I find this an unacceptable asssumption in a gravity field.

What do you think?
I think that it is a correct assumption in absence of heat flow, due to properties of Maxwell distribution.
Climbing in a gravity field, the slower molecules fall back down, but the faster molecules slow down. The net result is that at an higher altitude, there are fewer molecules, but their average speed is exactly the same as below.
 
Thread closed temporarily for Moderation...
 
jim mcnamara said:
@Geoffw
What I think: please supply a source (refereed ) article for your comments. I cannot separate what you think from what you are basing your statements on.
Thanks!
Thread will remain closed until @Geoffw can send me a private message with the refereed papers that he is referring to.
 

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