XPost: rec.arts.drwho, alt.usage.english   
   From: athel.cb@gmail.com   
      
   ram@zedat.fu-berlin.de (Stefan Ram) posted:   
      
   > doctor@doctor.nl2k.ab.ca (The Doctor) wrote or quoted:   
   > >In article <1rnygoz.1e95pzz18vjp88N%nospam@de-ster.demon.nl>,   
   > >J. J. Lodder  wrote:   
   > . . .   
   > >>[1] Beware, Celsius is always degrees, because Celsius is a scale.   
   > >>'Kelvin' otoh is a unit, and writing 'degree Kelvin' is an error.   
   >   
   > doctor@doctor.nl2k.ab.ca (The Doctor) writes:   
   > >Still interchangable.   
   >   
   >   Among people who actually know the field, "kelvin" counts as both   
   >   a unit and a scale. To back that up, I'm just going to quote a   
   >   bit from the well-known online encyclopedia "Wikipedia".   
   >   
   > |The kelvin (symbol: K) is the base unit for temperature in   
   > |the International System of Units (SI). The Kelvin scale is   
   > |an absolute temperature scale that starts at the lowest   
   > |possible temperature (absolute zero),   
      
   Coldest, yes, but not lowest, because negative kelvin values are possible. They   
   aren't possible at equilibrium, but they can certainly occur in sub-systems   
   that   
   are not at equilibrium. The most obvious example is for nuclear spin states in   
   nuclear magnetic resonance experiments. If you allow a sample to reach   
   equilibrium in the presence of a strong magnetic field and then suddenly   
   switch the polarity of the magnetic field the spins respond rather slowly and   
   so immediately after the switch the higher energy levels are more populated   
   than the  lower levels, and if you calculate the corresponding temperature in   
   kelvins it is negative. Notice that that is not extremely cold, it is extremely   
   hot, beyond infinity. When the spins relax to a new equilibrium distribution   
   they don't pass via O K, but via infinite K.   
      
   > taken to be 0 K.   
   > Wikipedia   
   >   
   >   
      
      
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   athel   
      
   Living in Marseilles for 38 years; mainly in England before that   
      
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