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Noether's Theorem and the real world

  1. Jun 10, 2015 #1

    Noether's theorem comes from the symmetries of the world. In the real world the distribution of galaxies and materials are inhomogeneous. Noether's theorem does not stand for the real world, so conxervations of energy, momentum, angular momentum do not stand exactly. Is it OK? Thanks in advance for your teachings.
  2. jcsd
  3. Jun 10, 2015 #2


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    This does not matter. The matter distribution does not need to be invariant under the transformation for it to be a symmetry, Noether's theorem relates to the invariance of the action.
  4. Jun 10, 2015 #3


    Staff: Mentor

    Noether's theorem comes from the symmetries of the Lagrangian. In other words, the symmetries of the laws of physics.

    The boundary conditions are added later.
  5. Jun 10, 2015 #4
    Thanks a lot!
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