What's the fastest the temperature of something can change?

[SpeedOfLightYagami]

Is there a temperature-change equivalent to the speed of light?

 

[Orodruin]

Not really, no.

 

[sophiecentaur]

Is there a temperature-change equivalent to the speed of light?

Perhaps more like the speed of sound.

 

[jbriggs444]

Is there a temperature-change equivalent to the speed of light?

This would be the rate of propagation of a temperature change? In a detonation, that can be quite rapid and can exceed the speed of sound. In a deflagration the propagation is, by definition, lower than the speed of sound.

Or is this the rate at which the temperature at a particular point varies over time? That could be quite rapid in, for instance, a nuclear weapon. Given the thermodynamic definition of temperature, the rate at which an equilibrium can be established would be key. Temperature is technically undefined in the absence of an equilibrium.

 

[DaveE]

Is it fair to speak of the temperature of a single atom? It seems like n=1 is kind of missing the "statistical" part of Statistical Mechanics. 2 atoms?
Anyway, if so it could be as quick as interacting with a photon.

 

[DaveE]

In practice, I'd vote for Ultra Fast Laser Material Processing. Which could be less than a picosecond.

 

[Baluncore]

Is there a temperature-change equivalent to the speed of light?

No.
The rate of temperature rise depends on the energy delivery mechanism.
Stay away from hydrogen bombs.

For a kinetic gas, it is the speed of sound, or the rise-time of the shock front. That increases with the square root of the absolute temperature.

For heating by EM radiation, the front propagates at the speed of light in the dielectric. The particles being heated will accelerate, and depart the scene at a rate, again determined by the rise time of a shock front.

For explosives, it is the energy yield and the molecular weight of the combustion products that decides the propagation of the detonation wave. The time the chemical reaction takes to complete, is the speed of temperature rise.

There are too many scenarios to analyse all. You need to be more specific about the situation.

 

[sophiecentaur]

Is it fair to speak of the temperature of a single atom?

Which one would you choose?

 

[DaveE]

Which one would you choose?

It doesn't make much sense to me for really small systems. Like two atoms one of which was just excited by a photon? 10 atoms? A billion atoms exposed to a terawatt laser pulse? It seems pointlessly pedantic to an engineer like me. But I'm definitely not a physicist. There is much about Temperature, Stat. Mech., Entropy etc. that I don't really understand.

I'll vote for Temperature having no meaning at all without a concurrent description of the application it's being used to describe.

 

[DaveC426913]

There are too many scenarios to analyse all. You need to be more specific about the situation.

He was specific. He only cares about the fastest one.

 

[mfb]

Laser pulses can heat samples from nothing to millions of degrees in a nanosecond.

Heavy ion collisions can change the system from something that doesn't have a well-defined temperature to a trillion degrees in ~10^-23 s.

There is no fundamental limit on temperature rise specifically.