Can absolute zero ever be achieved?

  1. Can absolute zero ever be achieved? I this a theoretical kinetic energy?
  2. jcsd
  3. Danger

    Danger 9,663
    Gold Member

    It's more a theoretical lack of energy. Although we've come very close to it with liquid helium, I don't think that it's practically attainable. You would need, to start with, a perfect insulator, which doesn't exist.
  4. nicksauce

    nicksauce 1,275
    Science Advisor
    Homework Helper

    Isn't the point of the third law of thermodynamics that it is impossible to reach absolute zero?
  5. Danger

    Danger 9,663
    Gold Member

    Correct, at least the way that I learned the 4 laws.
    1) No matter how hard you try, the best that you can do is break even.
    2) You can only break even at absolute zero.
    3) Absolute zero is impossible to attain.
    4) No matter how hard you shake it, the last drop always goes down your pants.
  6. Number 4... ROFL

  7. I hate that SO much. :grumpy:

    If absolute zero is impossible to attain, then is it not found anywhere in the universe? Is it something that just cannot be broken, in terms of going any lower?
  8. if absolute zero is obtained the universe will collapse into itself...
  9. Danger

    Danger 9,663
    Gold Member

    I'm not so sure about the collapsing part, but the universe as a whole is still permeated by the cosmic microwave backgound 'noise' from the Big Bang. That's something like 3 degrees K.. To attain absolute zero, you'd have to isolate a container of some type, and then pump out those 3 degrees. I'm not saying categorically that it's impossible, because technology continues to take me by surprise, but our current methods aren't up to it.
  10. Erm...why?

  11. You would also need to have perfect insulation would you not?
  12. Danger

    Danger 9,663
    Gold Member

    As mentioned in post #2, yes. I don't believe (just my opinion) that there can be such a thing, given quantum fluctuations and whatnot.
    Last edited: Jan 25, 2008
  13. I don't remember the the Laws of Thermodynamics forbidding absolute zero, but either way it's still impossible to attain absolute zero. To do so would be in violation of the Heisenberg Uncertainty Principle as if a particle is at absolute zero you would be able to learn it's precise position and velocity.
  14. Danger

    Danger 9,663
    Gold Member

    I never thought of it that way, but it makes sense. Its energy and movement would both be '0'.
  15. and if u get particles to stop moving what do you thing will happen to everything around it...
  16. Danger

    Danger 9,663
    Gold Member

    Not much.
  17. Really in order for absolute zero to be achieved, which it isn't but hypothetically here, the matter being put at absolute zero would have to be secluded from all other matter and shielded from radiation. Even if it wasn't it just means that you'll start slowly cooling other stuff too.
  18. Danger

    Danger 9,663
    Gold Member

    Bingo! And by cooling other stuff, you're gaining heat from it.
  19. Therefore it's impossible to reach absolute zero until all atomic motion in the system (universe) has been stopped.

    As has been said before, perfect insulators don't exist. If one atom isn't moving and there's an atom that is moving near it, the one that isn't moving will steal some of the energy from the moving atom and start to move.
  20. It's fundamentally impossible to get any part of the universe to reach absolute zero, the part about needing the insulation was just a matter of hypothetical thinking.
  21. Theoretically? Yes you can reach it if you have a perfect insulator (which is impossible)

    and because there does not exist a perfect insulator in the universe, as long as there is heat somewhere in the universe, its not possible. Besides, the moment you try to measure it to make sure all motion has stopped, you will have inadvertently heated it back up again. You'd be stuck with a container that you cannot touch, pointing at it and screaming eureka with absolutely no way to prove theres anything inside to begin with
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