Noether's Theorem and the real world

[sweet springs]

Hi.

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.

 

[Orodruin]

In the real world the distribution of galaxies and materials are inhomogeneous.

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.

 

[Dale]

Noether's theorem comes from the symmetries of the world

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.

 

[sweet springs]

Thanks a lot!