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Larry Jacks
2006-Nov-01, 10:30 PM
There are some interesting questions on this board. Here's one that was passed my way quite a few years ago. A good friend of mine is a high school science teacher. One day, he was discussing absolute zero, the coldest possible temperature. One of his students asked, "Is there an absolute maximum temperature?"

I gave him an answer and he passed it to his student. Before I give my answer (and it may be wrong), I'd like to hear the views of people on this board. Is there an absolute maximum temperature?

antoniseb
2006-Nov-01, 10:35 PM
In the past, I have said that the maximum temperature would be the temperature you'd get from two electrons hitting each other, each with half the total energy in the whole universe... but I realize now that there can be a higher temperature, depending on details of string theory, Planck scales, and the nature of the singularities in black holes.

korjik
2006-Nov-02, 12:02 AM
As you get to higher temperatures, the very concept of temperature starts to get fuzzy. Alot of plasmas can have 3 different temeratures, depending on what you are looking at.

Ufonaut99
2006-Nov-02, 12:55 AM
When I was at school, I remember an experiment where we did something like measure the temperature and pressure of some water at room temperature, then again after we added some ice. The idea was to extrapolate the graph to find absolute zero (I don't remember the precise details, but I do remember that my team got the most waaaay off answer in the class :doh: )

Anyway, they then went on to explain the relationship between temperature and atoms vibrating, with absolute zero being atoms being still (ie. vibration velocity = 0).

Since which time, I've always wondered of there's a maximum temperature where the atoms vibrate at c ?

RussT
2006-Nov-02, 01:28 AM
In the past, I have said that the maximum temperature would be the temperature you'd get from two electrons hitting each other, each with half the total energy in the whole universe... but I realize now that there can be a higher temperature, depending on details of string theory, Planck scales, and the nature of the singularities in black holes.

[singularities in black holes]

When a star masive enough to be a SNII goes supernova...what's the Temp?

AGN...what's the Temp?

Quasars/Blazars...what's the temp?

My suggestion would be...that whatever the Progenitor of the Massive Black Holes is...is the Highest possible Temp.

The problem with this though is...we cannot measure TeV Gamma energy correctly from any distances because it is absorbed on it's way to earth!

George
2006-Nov-02, 02:28 AM
Is there an absolute maximum temperature? Yes, and it varies as the inverse square of your distance from its source. :)

jseefcoot
2006-Nov-02, 05:42 PM
When I was at school, I remember an experiment where we did something like measure the temperature and pressure of some water at room temperature, then again after we added some ice. The idea was to extrapolate the graph to find absolute zero (I don't remember the precise details, but I do remember that my team got the most waaaay off answer in the class :doh: )

Anyway, they then went on to explain the relationship between temperature and atoms vibrating, with absolute zero being atoms being still (ie. vibration velocity = 0).

Since which time, I've always wondered of there's a maximum temperature where the atoms vibrate at c ?

I'm nowhere near so well learned as the majority of people on this board, but to me this concept has the ring of truth to it. I too learned in school that absolute zero can also be thought of as a cessation of all motion. It makes logical sense that the maximum temperature would correlate to the maximum velocity of the atoms.

But would the atoms be able to vibrate at such massive speeds? At which point might the atoms start to fall apart, or disassociate from one another, or something of the like?

antoniseb
2006-Nov-02, 06:03 PM
At which point might the atoms start to fall apart, or disassociate from one another, or something of the like?

As far as astrophysics is concerned, Atoms fall apart at relatively low temperatures. The center of our Sun is over ten million degrees which is hundreds of times hotter than what it takes to strip the electrons off of Hydrogen atoms... And the Sun isn't especially big for a star, and it isn't exploding.

Larry Jacks
2006-Nov-02, 06:19 PM
My thoughts when asked the question were based on the notion that one definition of temperature is the average kinetic energy associated with the molecules and atoms of a substance, as explained here (http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/temper.html#c1).

My first hunch was hat if temperature is a measure of kinetic energy, then since kinetic energy = 1/2 * mass * velocity^2 and c is the limit of velocity, then there was an upper limit to temperature (when the velocity of the atoms equals c). However, that fails to allow for relativistic mass increase with velocity.

Mass increase approaches infinity as velocity approaches c as explained here (http://en.wikipedia.org/wiki/Relativistic_mass). I ran a series of equations where I took the mass of a proton and kept increasing the velocity closer and closer to c and calculated the kinetic energy. As I kept adding "9s" to c = 0.999, the kinetic energy kept increasing, implying that temperature was also increasing. That being the case, I don't think there's an upper limit on temperature.

As a practical matter, there will probably be a point where the proton would break into it's fundamental quarks or something like that. I gave my results to my friend and asked him to thank his student for asking such an interesting question. You want to encourage kids to ask such questions.

Swift
2006-Nov-02, 10:11 PM