Temp Limits: Speed of Light, Absolute Zero & Kinetic Energy

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Discussion Overview

The discussion revolves around the relationship between the speed of light, absolute zero, and temperature, particularly focusing on whether these concepts impose limits on molecular motion and kinetic energy. Participants explore these ideas from both classical and relativistic perspectives, raising questions about the implications of these limits on temperature and energy.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • One participant questions whether the speed of light imposes a limit on molecular motion and thus on temperature, suggesting that approaching the speed of light may have significant implications.
  • Another participant asserts that absolute zero represents minimum motion, not zero motion, and challenges the notion that it cannot be reached due to the uncertainty principle.
  • A participant emphasizes that temperature is a function of energy rather than velocity, arguing that while there is a velocity limit, there is no corresponding limit on energy.
  • Some participants propose that the maximum temperature could be the Planck temperature, although this claim is questioned by others.
  • There is a discussion about the relationship between kinetic energy and temperature, with some asserting that the velocity limit affects temperature, while others argue that energy does not have a limit.
  • One participant critiques the use of non-relativistic kinetic energy expressions to draw conclusions about relativistic scenarios.

Areas of Agreement / Disagreement

Participants express differing views on whether the speed of light and absolute zero impose limits on temperature and kinetic energy. There is no consensus on these points, with multiple competing perspectives remaining throughout the discussion.

Contextual Notes

Participants reference various physical principles, including the uncertainty principle and special relativity, but do not resolve the implications of these principles on the discussed concepts. The discussion includes assumptions about the definitions of temperature and energy that are not universally agreed upon.

pzona
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Please excuse my lack of proper terminology, I've only just graduated high school so I'm by no means an expert on anything regarding physics.

My question is this: since there is a natural limit to the velocity of an object, the speed of light, and temperature is measured by kinetic energy of molecules of a substance, does that mean that the speed of light imposes a limit on how fast the molecules can move, and thus imposes a limit on the temperature? I'm not looking at it from a relativistic point of view, and I haven't really considered any of the consequences of the molecules approaching the speed of light, is this perhaps more important than I suspected?

On a semi-related note, is absolute zero a limit on the other end of the temperature spectrum? The way I see it, if all particle motion stops, this violates the uncertainty principle. So absolute zero cannot be reached, correct?
 
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Neither of those statements is true. Absolute zero refers to the state of minimum motion, not a state of zero motion. Temperature is more accurately described as a function of energy, not velocity, and while there is an upper limit to an object's velocity, there is no such limit for energy.
 
The temperature of a substance depends on the average kinetic energy of the molecules in the substance, (which depends on the square of the average velocity blah blah blah). While there is a limit on the velocity of the molecules (the speed of light), the theory of special relativity shows that there is no limit to an object's kinetic energy, thus there is no limit to temperature (for all we know). What I'm trying to say is that you shouldn't put a burrito in the microwave for more than seven minutes...

As for absolute zero, listen to Vanadium, he's more experienced than I.
 
Vanadium 50 said:
... Temperature is more accurately described as a function of energy, not velocity, and while there is an upper limit to an object's velocity, there is no such limit for energy.

I think there's such a limit, at least in the gas phase. Consider the temperature of a mixture of gas. The temperature is expressed in term of gas molecule (or electrons & nuclei if it's too hot) velocity. The particles' velocity is limited so the temp is also limited isn't it?
 
My understanding is the maximum temperature possible is Planck temperature.
 
pixel01 said:
I think there's such a limit, at least in the gas phase. Consider the temperature of a mixture of gas. The temperature is expressed in term of gas molecule (or electrons & nuclei if it's too hot) velocity. The particles' velocity is limited so the temp is also limited isn't it?

No. As I said, temperature is a function of energy: it's proportional to kinetic energy, so while there is a velocity limit in SR, there is no kinetic energy limit.
 
jobyts said:
My understanding is the maximum temperature possible is Planck temperature.

Why would this be true?
 
Vanadium 50 said:
No. As I said, temperature is a function of energy: it's proportional to kinetic energy, so while there is a velocity limit in SR, there is no kinetic energy limit.

We have this formula: T = (2/3)*(1/k)*(mv^2)/2
v has a limit so you mean m can rise?
 
You have the non-relativistic expression for kinetic energy in there and are attempting to use it to draw relativistic conclusions.
 

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