The Conservation of Energy is NOT Absolute (Noether's Theorem) #physics

3-Second Blueprint (English)

1. As space expands, traveling photons undergo cosmological redshift, stretching their wavelength and reducing their energy without transfer.
2. Noether's theorem proves that every physical conservation law stems from a continuous symmetry, linking energy conservation to time invariance.
3. Because an expanding universe has a time-varying spacetime metric, time-translation symmetry breaks and global energy is not conserved.