>SNIP
>Negative Kevin temperatures don't exist because Zero Kelvin is defined as
>>the temperature at which all motion, including atomic motion ceases. We have been able to get within a few millionths of a degree of Zero Kelvin, as defined by the temperature of the heat sink in the engine we have devised to do so.
>
>Jerry,
>
>When the so-very-near 0 Kelvin was achieved did the item(s) being cooled and the cooler itself simply turn into a pile of "disconnected" molecules?
>

Actuall, they start with a pile of disconnected molecules --- atoms. To stick to theory, the high temperature source has to be so massive that the amount Q removed won't perceptible lower its temperature, and the same for the heat sink... the amount of Q added to it won't raise it's temperaure. Think of taking a teaspoon from a swimming pool letting it flow through a turbine to another swimming pool at a lower elevation. If the amount of water running through the turbine drops the level of the upper swiming pool and raises the surface level of the lower swimming pool, then the efficiency of the turbine drops, because it is based on the differences in hights of the surfaces, and less net work can be extracted to power light bulbs, etc.... At extremely low temperatures both the 'high' temperature heat source and the low temperature heat sink are at very low temperatures, and the upper swimming pool "leaks" into the lower one, making extracting useful work difficult. This "leaking" is the random motion of atoms and particles. To lower the surface of the lower swimming pool (lower the temperature of the heat sink) a refridgerator (which is just a heat engine run backwards) accepts some work at the input of the PTO, so to speak, and uses it to drag some Q from the lower sink to the upper source, just the way a refridgerator cools the ice box inside. At those low temperatures the efficiency is so low that it take an very large amount of input work on the PTO to pump even a small amount of Q from the low sink to the high source. Think of a heat engine which takes 100 calories from a heat source, at Th, converts part to useful output work and dumps the rest to the heat sink. Exactly how much can be extracted as useful work is given by (Th-Tl)/Th. Say, (1000K - 100K)/1000K = 90%. 10 Calories MUST go to the sink. If I were to run this engine backwards to cool down the heat sink it would require me to use 90 calories of heat to pump 10 calories from the sink to the source, coolng the sink. Now... (100K-10K)/100K is also 90% but (100K -1k)/100K = 99%. It would take 99 calories to pump up one calorie from the 1K sink to the 100K source. (100k-0.1K)/100k = 99.9% It would take 999 calorise to pump up one calorie from the 0.1K sink. We have to have Th and Tl as far apart as possible to make the efficieny as high as possible. Make any sense?
JLK