Energy is the ability of causing change.

Change is related to time.

That’s why energy is related to time.

— Me@2012-10-22 01:45:17 PM

Application of Noether’s theorem allows physicists to gain powerful insights into any general theory in physics, by just analyzing the various transformations that would make the form of the laws involved invariant. For example:

- the invariance of physical systems with respect to spatial translation (in other words, that the laws of physics do not vary with locations in space) gives the law of conservation of linear momentum;
- invariance with respect to time translation gives the well-known law of conservation of energy

— Wikipedia on *Noether’s theorem*

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