Heat has no upper boundries?

[Wycco]

I was reading the F1-Live thread where Rizzla made a fool out of SFW over absolute zero...

(SFW thought you could go below absolute zero- and quoted the following from an online website)

There is no limit to how hot an object can be, but the lowest temperature is absolute zero at -273.15deg.C or 0 K. The lowest temperatures which occur naturally are on Triton in the Solar System and in inter-galactic space. Much lower temperatures can be created in the laboratory,

Rizzla found the same website- and posted the link and the quote IN FULL... what SFW left off was:

but not as low as Absolute Zero

Anyhow- after laughing my ass off at SFW for a few minutes it got me thinking...

There is no limit to how hot an object can be

Surely this is an assumption... and cannot be proved... it even SOUNDS incorrect to me...

Heat is caused (if I remember high school science correctly) from the movement of atoms... the faster the atoms moves... the hotter those atoms become.

It is believed by most that the speed of light in a vacuum is the fastest possible speed atainable. If so- would that not imply that when atoms in an object start moving around at the speed of light- that object has reached a maximum temperature?

How can an object get hotter then when all its bits and pieces are at light speed... that to me would an upper limit on how hot things can get! Thus making the above quote incorrect.

[alexmd]

well i think you're right. if you heat an object enough it turns to plasma or something, right? so you don't even have the original material anymore at some point.

[CFF]

Wycco said:

How can an object get hotter then when all its bits and pieces are at light speed... that to me would an upper limit on how hot things can get! Thus making the above quote incorrect.

Wycco - The answer, in a nutshell, is PRESSURE. Temperature varies directly as pressure changes, hence there is no theoretical limit to maximum temperature.

CFF

[rick1776]

Its been too many years since I did first year relativity but wouldnt something possessing mass have infinite mass at the speed of light?

mass = m/(m – (v^2/c^2))^0.5


Damn, so as Ferrari become faster and faster they are penalised by having a heavier car!

cheers
rick1776

[CFF]

rick1776 said:

Its been too many years since I did first year relativity but wouldnt something possessing mass have infinite mass at the speed of light?

Rick - I'm sure what you meant to say was that anything possessing mass CAN'T reach the speed of light. Things with mass will have their mass increase to infinity as they approach the speed of light, but it's theoretically impossible for anything with mass to actually reach the speed of light.

CFF

[Pabs]

Alright, I'm going to take a stab at this one...

First of all, I guess we need to make the clarification that the regular concept of temperature is an indication of the mean translational energy of the molecules in a gas. However, there are other energy storage modes available: vibrations, rotations, dissociation, ionization. Each one of these modes can have a "temperature" associated with it. In that sense, temperature ceases to be defined as we know it and it becomes an indication of how the energy is distributed in the atom or molecule.

As to the upper-limit of heat, I think there are limits to how hot an object can get. First of all, there is only a finite number of energy modes and energy levels available to store energy. Beyond that, the energy will have to go to translation of the molecules and as Rick and CFF pointed out, molecules can not travel faster than the speed of light.

Finally, CFF refers to the equation of state (relationship between the thermodynamic variables). However, pressure also has a limit. For example in a star, gravity counteracts pressure. And when gravity is much too high, for example, the star collapses onto itself and forms a black hole.

So in short, I think heat has an upper limit, but of course I could be wrong.

[CFF]

This has been a boring Sunday since the race ended, and so I got to thinking about this ongoing debate about an upper limit to heat (temperature). Have been purusing the web, searching for an accurate answer to this question, and have just come across this *and while I will C'n'P it, let me just say there ARE differing opinions on this subject, so this is by no means the final word*

As the speed of an object gets closer and closer to the speed of light, its mass increases. If an object could travel at the speed of light, its mass would be infinite. So, there is not upper limit to the amount of kinetic energy an object can have, even though there is an upper limit to its speed. Temperature is a measure of average molecular kinetic energy, so there is consequently no upper limit to temperature, either.

Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois

I'd like to add that scientists have recently found other ways to add to the kinetic energy of a mass (other than increasing either the mass itself OR by increasing the mass's velocity). It has been shown that additional energy can be added to a mass by subjecting it to other forms of energy i.e. laser in the case I'm referring to.

CFF

[pabs]

But there's a finite amount of energy modes in which a molecule can store energy. Much beyond that point, the molecule will find ways to get rid of that energy, for example radiation. I tend to think that nature prevents things like infinite heat from happening. As a side note, a molecule with an infinite capacity for storing energy will a have a ratio of specific heats identically equal to zero which is not possible according to real gas theory (which I understand pretty well). My knowledge of quantum physics is rather limited so I don't want to get into that too much.

Also, this poses a good question: if a molecule could achieve infinite heat, then what does that say about the total amount of energy in the universe? The only time when I could imagine an inifite amount of energy would be the singularity that went kaboom!! also known as the big bang....Right Cine? ;D

Adding kinetic energy by means of a laser has been around for a while. But funnily enough, one of my best buddies here is working on supercooling of gases by doing the same: whacking an expanding gas with a laser beam (3 of them actually). The process is different though.

[CFF]

Right you are about the supercooling using lasers Pabs. Get's into spin states - something I don't profess to know enough about to begin sharing with others here (besides ... it is rather a dry topic ... and it would lead to the suggestion that in fact there are temperature levels possible that are below 0 K (absolute zero).

As far as an infinite amount of energy being present at the moment of the big bang, I'm sorry to report that in fact, there was an energy balance taking place (all positive energy created by expanding matter was balanced by the negative energy of the growing gravity field). Hard to believe ? check:

www.netusa1.net/~kazik/page1.html

CFF

[Pabs]

No...not hard to believe at all. In fact as I was writing my earlier response, I was going to suggest that there is a finite amount of energy in the Universe. So I changed it to what I said about the big bang: with my limited knowledge, that's the only time when I can imagine there being an infinite amount of energy. But you cleared that up rather nicely for me.

But then that leads me to my next question: if there is in fact an energy balance, how can the universe be infinite (as we believe it is?)

About the lasers, yeah it is a rather boring topic. I understand the basic physics behind it but that's about it. My research involves gas-light interactions so I have to know a fair bit about quantum mechanics...enough to do my measurements.

[Wycco]

Thanks guys, intersting points on both sides... I wish I had something to add!

[Srrh]

Guest-Pabs said:

But then that leads me to my next question: if there is in fact an energy balance, how can the universe be infinite (as we believe it is?)

Infinite BUT expanding...

[CFF]

Guest-Pabs said:

But then that leads me to my next question: if there is in fact an energy balance, how can the universe be infinite (as we believe it is?)

Pabs - On June 30, 2001, NASA launched what may be one of the most important probes ever: WMAP *Wilkinson Microwave Anisotropy Probe*. The resulting data has confirmed a number of ideas about cosmic origins, including:

• Universe is 13.7 billion years old with a margin of error of close to 1%.
  
• Contents of the universe are 4% Atoms, 23% Cold Dark Matter, and 73% Dark energy. *The data places new constraints on the dark energy. It seems more like a "cosmological constant" than a negative-pressure energy field called "quintessence". But quintessence is not ruled out. *
  
• the universe continues to expand *Expansion rate (Hubble constant) value: Ho= 71 km/sec/Mpc (with a margin of error of about 5%)*
  
• the universe is flat (as opposed to open *negatively curved* or closed *positively curved like the surface of a sphere*)
  

*for more on the WMAP, goto NASA's WMAP homepage at map.gsfc.nasa.gov/ *

I'd like to point out something that helps mere mortals envision how a universe which is close to infinite in size can still be expanding *that's a tough concept to wrap your head around*.

Consider, if you will, the distinction between 'SPACE' and the 'UNIVERSE'. While not generally thought of as two distinct entities, it's helpful when contemplating how a vast (near-infinite) universe can still be expanding .... *"expanding beyond what?" is the most commonly asked question*.

Prior to the big bang (13.7 billion YA), there existed a domain known as space. It was, and continues to be, infinite .... . The universe can be thought of as ~the contents~ that began to occupy this space when the big bang occured. These contents have now been shown to be made up of 4% matter, 23% cold dark-matter, and the rest (73%) dark-energy. Matter is everything made of atoms *physical stuff*. Cold dark-matter can be thought of as rare subatomic particles, or even 'anti-matter'. The biggy, dark-energy, has been described as ~anti-gravity~, but I'd be foolish to try to explain it in any more detail now, as there is little science to back me up.

So ..... getting back to the universe expanding, all this 'stuff' (matter, cold dark-matter and dark energy) is expanding out thru empty space at the rate of 71 km/sec/Mpc *otherwise known as the "inflation theory"*.

And I'll leave it there for now ......

CFF