Symmetry in Physics

Physicist Emmy Noether proved that every symmetry in nature corresponds to a conservation law. Symmetry in time gives conservation of energy. Symmetry in space gives conservation of momentum. This theorem is considered one of the most important results in theoretical physics.

When physicists say the laws of physics are the same everywhere in the universe, they are stating a symmetry. Symmetry breaking — when this uniformity fails — explains why matter has mass, why magnets have north and south poles, and why the universe isn't a featureless soup.