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Why is absolute zero finite compared to maximum heat (which is seemingly infinite)?



 
 
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  #21  
Old December 11th 03, 11:06 PM
Mark Folsom
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Default Why is absolute zero finite compared to maximum heat (which is seemingly infinite)?

"Henry Allen" wrote in message
om...

Perhaps you should find out how temperature is defined?

Absolute zero is when the average velocity of particles
is zero.

Absolute zero is when the velocity of all particles is zero.


Nope--there's a zero-point energy that isn't zero.

The
average velocity of the particles that make me is zero relative to the
floor because I'm not moving Temperature is a measure of the
kinetic energy of a system of moving particles that has zero net
velocity...


It's actually translational kinetic energy. Rotation and internal vibration
of molecules don't show up in the temperature. If you have a diatomic
molecular gas in thermal equilibrium with a monoatomic gas (and the
temperature is high enough to activate other than translational motion), the
diatomic species will have more energy per molecule.


The highest possible temperature is when the average
velocity of particles approaches the speed of light.

Temperature is a measure of energy not

The highest possible temperature is not limited by the speed of light-
it's limited by the amount of energy in the universe...because you can
always dump more energy into a moving particle even though it gets no
faster.

So I've always been puzzled that one of the limiting design parameters
of spacecraft is the amount of reaction mass avaliable-- since you can
make anything that has mass contain an infinite amount of energy one
electron accelerated fast enough and shot out of the talepipe should
bring you up to light speed regardless of the mass of your spacecraft.
Granted this approach has a few engineering problems...


You also need to factor in specific impulse.

Mark Folsom


  #23  
Old December 12th 03, 03:21 PM
[email protected] \(formerly\)
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Default Why is absolute zero finite compared to maximum heat (which is seemingly infinite)?

Dear mmeron:

wrote in message
...
In article , "Greg Neill"

writes:
...
Quantum mechanics says you can't ever completely eliminate
tiny jiggles of the constituent particles, so the temperature
of a collection of particles can never reach absolute zero.

And that's quite wrong. If a system is at its lowest possible state,
it is at zero temperature.


Not to feed any flames...
A system could be a dewar of a substance that we have deemed to be at its
lowest energy state. With the little "jigglings", would it be meaningful
within our system (that little Universe sub-set) to ascribe non-zero
"local" temperature? So, is temperature relative?

David A. Smith

  #25  
Old December 12th 03, 10:42 PM
Stewart Smith
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Default Why is absolute zero finite compared to maximum heat (which is seemingly infinite)?

Here's an interesting aside:

Is this the beginnings of a Freeze Ray device?

Molecules Knocked Cold
---------------------------------------------------------------------------

Chemists have long used supersonic gas expansions to create beams of
molecules that are "cold" in the sense that the molecules are in low
vibrational and rotational states and do not undergo collisions. However,
translational motion of the molecules still makes them "hot" in the
laboratory frame of reference, and this temperature broadening creates
noise that obscures many experimental signals. Elioff et al. (p. 1940) show
that single "billiard-like" collisions between the molecules of two
molecular beams can produce a population of molecules that essentially come
to rest in the lab frame and achieve true temperatures below 1 K. Inelastic
collisions between beams of NO molecules and argon atoms produced between
108 and 109 NO molecules in a specific quantum state with speeds no greater
than 15 meters per second, which corresponds to a maximum temperature of
0.4 Kelvin.

Science




"John" wrote in message
...
On 9 Dec 2003 12:45:56 -0800, (Binary Object)
wrote:

Why is absolute zero approximately -460 F, yet the maximum
possible amount of heat is seemingly infinite? There is
certainly an asymmetry. Why is there no upper bound for
heat? Why is there a lower bound for cold?


As I understand it, at absolute zero temperature, molecular vibration
ceases. You can't have less than zero (or negative) vibration, but
theoretically there is no upper limit to degree of vibration.



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  #27  
Old December 13th 03, 12:03 AM
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Default Why is absolute zero finite compared to maximum heat (which is seemingly infinite)?

In article z9kCb.4199$gN.2607@fed1read05, \(formerly\)" writes:
Dear mmeron:

wrote in message
...
In article , "Greg Neill"

writes:
..
Quantum mechanics says you can't ever completely eliminate
tiny jiggles of the constituent particles, so the temperature
of a collection of particles can never reach absolute zero.

And that's quite wrong. If a system is at its lowest possible state,
it is at zero temperature.


Not to feed any flames...
A system could be a dewar of a substance that we have deemed to be at its
lowest energy state. With the little "jigglings", would it be meaningful
within our system (that little Universe sub-set) to ascribe non-zero
"local" temperature?


No.

So, is temperature relative?


Again, no. I repeat what I wrote in another post, tmeperature is
*not* (repeat, **not**, ***not***, ****not**** ....) kinetic energy.

Mati Meron | "When you argue with a fool,
| chances are he is doing just the same"
 




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