Temperature in Space: The Kelvin Scale

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SUMMARY

The Kelvin scale quantifies temperature as a measure of the kinetic energy of particles within a system. However, in the context of free space, where particle density is extremely low, the temperature is influenced by the cosmic microwave background radiation. The discussion emphasizes that temperature is a statistical property applicable to collections of particles, and in the absence of matter, such as in intergalactic space, temperature cannot be defined. The conversation also highlights the need for a more comprehensive understanding of temperature beyond kinetic energy alone.

PREREQUISITES
  • Understanding of the Kelvin scale and its application in thermodynamics
  • Familiarity with cosmic microwave background radiation
  • Basic knowledge of statistical mechanics
  • Awareness of particle physics and intergalactic matter
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  • Explore statistical mechanics and its implications for temperature measurement
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Niladri Dan
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The Kelvin scale states that the temperature is a measure of the kinetic energy of the particles(molecules) of the system. But what is the temperature of a system where there are no particles...for example free space, far away from the stellar civilisation...
 
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Niladri Dan said:
The Kelvin scale states that the temperature is a measure of the kinetic energy of the particles(molecules) of the system. But what is the temperature of a system where there are no particles...for example free space, far away from the stellar civilisation...

hi there

for a start have a read of some better definitions of the Kelvin scale compared to what you wrote

https://en.wikipedia.org/wiki/Kelvin

you will discover that temperature isn't just based on kinetic energy of the particlesDave
 
Niladri Dan said:
The Kelvin scale states that the temperature is a measure of the kinetic energy of the particles(molecules) of the system. But what is the temperature of a system where there are no particles...for example free space, far away from the stellar civilisation...

That definition of temperature in terms of the kinetic energy of the particles in a system is incomplete; we also have to include a contribution from whatever radiation, like the cosmic microwave background, is out there. And even intergalactic space is not completely devoid of matter - there are a few stray atoms floating around, and the occasional highly energetic cosmic ray coming through.
 
I have tried to think about the some thing but 'in the gaps' at molecular level of the atmosphere.
 
pBrane said:
I have tried to think about the some thing but 'in the gaps' at molecular level of the atmosphere.
The temperature "in the gaps" between molecules does not exist. Temperature is a statistical property of large collections of things such as atoms and molecules. If you restrict your attention to a setting with a collection of zero objects, temperature is no longer an attribute of that collection.

Apologies if I've misunderstood your posting.
 
jbriggs444 said:
The temperature "in the gaps" between molecules does not exist. Temperature is a statistical property of large collections of things such as atoms and molecules. If you restrict your attention to a setting with a collection of zero objects, temperature is no longer an attribute of that collection.

Apologies if I've misunderstood your posting.
Don't worry about it, I may have misunderstood my posting as well!
 
pBrane said:
Don't worry about it, I may have misunderstood my posting as well!
WOW ... over 2 years to respond ... almost a record :wink::biggrin::smile:
 
davenn said:
WOW ... over 2 years to respond ... almost a record :wink::biggrin::smile:
wuz time travlin, just sayin.. topic probably banned here so don't tell anyone!
 
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