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Law of Conservation of Energy

  1. Jan 14, 2005 #1
    If the Law of Conservation of Energy can be violated on a minor level via the Heisenberg's Uncertainty Principle, what prevents it from being violated on a macroscopic scale?
  2. jcsd
  3. Jan 14, 2005 #2


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    Staff: Mentor

    The Heisenberg uncertainty principle only makes a difference on the micro level, so it won't affect the 1st law of thermo on the macro level.
  4. Jan 14, 2005 #3

    Then what about the Big bang?

    I know its just a hypothesis, but wouldn't the ;aws of thermodynamics eleminate the chance of the big bang?
  5. Jan 14, 2005 #4
    No, everything is conserved nicely.

    Re: heisenberg uncertainty principle, this indicates that the conservation of energy can be broken but only for a time so short that we are unable to observe it. Therefore we know that this must happen otherwise many reactions in particle physics (and the virtual photon theory of EM) would not be possible.

  6. Jan 14, 2005 #5


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    Staff: Mentor

    Essentially, the big bang happened before the laws of the universe went into place.
  7. Jan 14, 2005 #6


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    It makes more sense to view the laws of physics as an emergent phenomenon, just like the big bang itself - as russ noted. The four fundamental forces, and all the laws of nature are believed to have emerged from a single unified quantum state. Gravity was the first, breaking free at the very first tick of time - 10E-43 seconds after the BB. Next came the strong nuclear force followed by the electroweak forces. The laws of physics, as presently known, were not operative until then.
  8. Jan 14, 2005 #7
    Also beware that this violation of energy-conservation can only occur for a very short time period...Nevertheless, indeed this violation only occurs on the microscopic level and has nothing to do with the macroscopic properties of matter. This treatement is followed and used to construct thermodynamics

  9. Jan 15, 2005 #8
    Just to underline what Marlon answer: we must not confuse the laws of conservation of the observables with the local outcomes of these observables. Total Energy and momentum are always conserved.

    Applying Heisenberg inequalities to energy just show how this total energy may be "distributed in time" and not that energy is not conserved.

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