The Coldest Repeal of Absolutes Thus Far.

[dream_weaver]

How to create temperatures below absolute zero

Objectivist who may have relied on this scientific assertion to tie the concept of absolutes to the science of physics may have to seek another example now.

Scientists Find 200 Sextillion More Stars in the Sky

And just in case you were trying to count, or lost count somewhere along the way - this might help illustrate why the identification of premises, or in this case, assumptions, could make a slight difference in the outcome.

[whYNOT]

'Space?' What space? Our neighborhood is getting overcrowded.

300, I can get my head around. But a sextillion.........?

[brian0918]

'Space?' What space? Our neighborhood is getting overcrowded.

300, I can get my head around. But a sextillion.........?

300 sextillion is half Avogadro's number - so it's the number of carbon atoms in 6 grams of the substance. (carbon-12, not an isotope)

Yep, atoms are tiny.

Edited December 2, 2010 by brian0918

[Steve D'Ippolito]

So they found half a mol of stars they didn't know about.

[Soth]

I may not be a physicist, but the negative temperature concept did not convince me. It appears they are rigging the system to sorta match what a reverse temperature (negative temp) would behave like, but they aren't doing so by manipulating temperatures.

[whYNOT]

I may not be a physicist, but the negative temperature concept did not convince me. It appears they are rigging the system to sorta match what a reverse temperature (negative temp) would behave like, but they aren't doing so by manipulating temperatures.

Yes, hard to swallow. I read somewhere that even deep space is at 3 degrees Kelvin - which has reinforced The Big Bang Theory to many scientists.

Artificially so far, the closest temperature reached is a billionth of a degree above zero K.

It seems achieving negative temperature involves halting all movement of atomic nucleii

inside a magnetic field.

The theory makes sense ...

[dream_weaver]

I may not be a physicist, but the negative temperature concept did not convince me. It appears they are rigging the system to sorta match what a reverse temperature (negative temp) would behave like, but they aren't doing so by manipulating temperatures.

The link within the primary article stated that it had already been done. I am at a disadvantage at this point as to understanding the technical jargon at this point.

[brian0918]

How to create temperatures below absolute zero

Objectivist who may have relied on this scientific assertion to tie the concept of absolutes to the science of physics may have to seek another example now.

On the contrary - reaching absolute zero is still an impossibility. It is just that in certain systems, adding energy *decreases* entropy, rather than increasing it - it is in these situations that the "temperature" in the relevant equations becomes a negative value. Thinking of "negative temperature" as somehow being "motion less than zero motion" is incorrect.

[dream_weaver]

On the contrary - reaching absolute zero is still an impossibility. It is just that in certain systems, adding energy *decreases* entropy, rather than increasing it - it is in these situations that the "temperature" in the relevant equations becomes a negative value. Thinking of "negative temperature" as somehow being "motion less than zero motion" is incorrect.

In two other specifications of temperature, 0°F and 0°C are merely reference points on a 'measuring stick'. I was thinking the article was lending support to consider 0°K similarly.

Personally, trying to comprehend that 0°K produces stasis say in a hydrogen atom in the sense that the electron somehow comes to a standstill is a little difficult to get the mind around.

As to 'entropy', Binswanger's assessment that it amounts to saying that which is most likely to occur, will, seems similar to the idea that chaos is an order that the mind has not categorized yet.

[brian0918]

In two other specifications of temperature, 0°F and 0°C are merely reference points on a 'measuring stick'. I was thinking the article was lending support to consider 0°K similarly.

It's not. F and C are arbitrary scales selected for their particular utility, whereas K is based on fundamental physical properties. Negative F and C are simply colder, whereas negative K is actually hotter than anything with a positive temperature (because heat will flow from it to a positive K system, no matter how hot the latter may be). Absolute zero is the point at which all thermodynamic motion ceases to occur. In these "negative temperature" systems, motion is not ceasing. It still occurs, but it leads to less entropy, rather than more.

This may all seem nonsensical - but that is because the concept is highly abstract. You cannot directly measure negative temperature. As with imaginary numbers or electron holes, negative temperature is a concept of method, and exists solely as a conceptual means toward other, physical ends.

Wikipedia quotes a textbook that puts it pretty clearly:

"The temperature scale from cold to hot runs:

+0 K, . . . , +300 K, . . . , +∞ K, −∞ K, . . . , −300 K, . . . , −0 K."

Edited December 5, 2010 by brian0918

[dream_weaver]

Thanks, that helps put it into perspective.

[Q.E.D.]

Temperature with the addition of negative absolute temperature is just a generalization of the concept of temperature. Generalizations such as this are not meant to invalidate the normally observed 'temperature' (they can't). Physicists often introduce generalized concepts in order to make complex systems more understandable.

0K represents the temperature at which atoms do not move, whether negative temperature exists or not.