Absolute Zero

Discussion in 'Chemistry' started by Orleander, Dec 29, 2007.

  1. saudade Unfiltered perspective... Registered Senior Member

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    Very interesting thread...
     
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  3. iceaura Valued Senior Member

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    Just a passing thought - what if it's gaining mass, so that more energy is required to get it back to +1 than was removed in getting it from +1 to 0 ?

    Not serious ! Just consdiering - - -
     
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  5. Frud11 Banned Banned

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    Absolute: from the Latin: ab, and solutus, ab means from, or by (agency), or even after, solutus means unbound, free, or scattered. Zero comes from Greek, means zero.

    There ye goest.
     
    Last edited: Jan 1, 2008
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  7. orcot Valued Senior Member

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    now what's the defenition of the word atom

    negative kelvin might not be impossible even though I still have to finish reading the article
    link
     
  8. Myles Registered Senior Member

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    De le ted
     
    Last edited: Jan 1, 2008
  9. Myles Registered Senior Member

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    There ye GOETH. Asinus ad lyram
     
  10. superluminal . Registered Senior Member

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    If you want to get esoteric about it, fine, but our common understanding and intuition about negative absolute temperatures is correct.

    http://istd.gsfc.nasa.gov/cryo/introduction/neg_Kelvin.html

    This sort of very specialized situation describes an abstract concept based on "population inversions" that I don't fully understand myself. It really has nothing to do with actual temperatures in normal systems.

    This model even includes "infinite temperature" which, if you think about it, is physically impossible due to relativistic limitations (can't really have atoms moving infinitely fast, can we?).
     
  11. Avatar smoking revolver Valued Senior Member

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    I think he meant the 5th state of matter - Bose–Einstein condensate.
     
  12. superluminal . Registered Senior Member

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    Hmm... Ok?
     
  13. Avatar smoking revolver Valued Senior Member

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    Well I think so because Bose–Einstein condensate like no other state is connceted with absolute zero.

    By the way I think it's theoretically impossible to go lower than absolute zero,
    at least not in our universe, or reach it for that matter.
     
  14. superluminal . Registered Senior Member

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    Right.
     
  15. Orleander OH JOY!!!! Valued Senior Member

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    OK, so do any of you think Wolfgang Ketterle will eventually get absolute zero? I mean he got 810 trillionths of a degree above it.
    Or, that is as close as we would ever want to come?

    (and I am not understanding how he made the BEC at all. I mean really? Its not a gas, liquid or solid??? WTHell?!)
     
  16. Avatar smoking revolver Valued Senior Member

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    No, theoretically you can get very, very, very close, but not 0,000..., not in this universe at least.

    At 170 nanokelvin atoms no longer behave like individual atoms, but due to quantum effects behave like one uniform wave. Fascinating really. There is nothing other like that in nature or in our human experience.

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    BBC has a documentary "The race to absolute zero", you might want to see it.

    http://www.mininova.org/tor/864833
     
  17. Frud11 Banned Banned

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    Whither goest ye, ye GOETH?
    Vades quosum, vadetis? Sic it adsumes.
     
  18. Orleander OH JOY!!!! Valued Senior Member

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    But I don't understand why?!
     
  19. Avatar smoking revolver Valued Senior Member

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    Universe is energy. Try getting rid of the universe.
    Eventually you'll reach a point where extracting some particular ammount of energy would take 14bn years and a machine the size of the universe, and it doesn't stop there.
     
  20. Orleander OH JOY!!!! Valued Senior Member

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    but aren't they trying to make a black hole in a lab? Why not absolute zero?
     
  21. Avatar smoking revolver Valued Senior Member

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    There's a fundamental theoretical and practical difference in the ammount of energy involved. Black hole doesn't mean getting rid of this universe.
     
  22. orcot Valued Senior Member

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    Yeah yust this earth
     
  23. superluminal . Registered Senior Member

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    Hang on everybody. Reality check.

    You cannot even theoretically reach absolute zero because of a very fundamental feature of quantum mechanics. The uncertainty principle states that you can never obtain both the position and momentum of a particle to arbitrary precision simultaneously. The very act of pinning down one attribute (say momentum) means that you cannot know the position of the particle at all, and vice versa. This is a consequence of the fact that quantum particles really are more of a probabilistic combination of these attributes (and other quantum numbers like spin). By pinning down one precisely, the other goes out the window so to speak and becomes completely indeterminate.

    So, true absolute zero implies that you would know the momentum of a particle (or a group of them) as being exactly zero, and the exact positions of the particles. This is a no-no. Not allowed. Can't do it.
     

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