Noether's Theorem and Arthur Eddington

Another shout out to Emmy Noether's (First) theorem.

Informally stated, if a system has a continuous symmetry property, then there are corresponding quantities whose values are conserved.

As an illustration, if a physical system behaves the same regardless of how it is oriented in space, angular momentum of the system must be conserved, as a consequence of its laws of motion.

Another illustration, if a physical process exhibits the same outcomes regardless of place or time, then linear momentum and energy must be conserved.

It is regarded as the foundation of particle physics