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That assumes that fundamental laws of physics did not change (will not change). This is what we believe and have no evidence otherwise. This is important since
by elashri 3y ago
That assumes that fundamental laws of physics did not change (will not change). This is what we believe and have no evidence otherwise. This is important since we rely on measuring atomic transitions of cesium atoms which itself were formed/forming billions of years after the big bang itself.
The laws of physics invariance under time is a core to our understanding. It would be very disrupting if we found otherwise.
- not2b 3y agoRight, but most deviations one can think of (like, changes over time to physical "constants") would have an observable effect, so ancient galaxies would look much more different from modern galaxies and spectra wouldn't look the same other than a red shift, which moves all the lines in a uniform way.