Temperature in Space: The Kelvin Scale

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The Kelvin scale measures temperature based on the kinetic energy of particles, but its application in empty space raises questions about temperature in the absence of particles. In free space, the temperature is influenced by cosmic microwave background radiation, which provides a minimal temperature reading. The discussion highlights that temperature is a statistical property of large collections of atoms and molecules, and cannot be defined in a void with no particles. Additionally, even intergalactic space contains sparse matter and radiation that contribute to temperature. Overall, the concept of temperature becomes irrelevant in a completely empty space devoid of matter.
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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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