I Non-homogeneous and anisotropic metric and laws of physics...?

[Suekdccia]

TL;DR

Non-homogeneous and anisotropic metric and laws of physics...?

In this popular science article [1], they say that if our universe resulted to be non-uniform (that is highly anisotropic and inhomogeneous) then the fundamental laws of physics could change from place to place in the entire universe. And according to this paper [2] anisotropy in spacetime could break the Lorentz invariance [3]

I know that there are metrics and spacetimes which are non-homogeneous and anisotropic. If our spacetime was highly anisotropic and inhomogeneous would this be possible? Can you think of some specific types of spacetimes or metrics where this could happen? Any examples that you can think of?[1]: https://whatifshow.com/what-if-the-universe-isnt-uniform/

[2]: https://doi.org/10.1038/s41598-021-86355-3

[3]: https://en.wikipedia.org/wiki/Modern_searches_for_Lorentz_violation

 

[PeterDonis]

In this popular science article [1]

Pop science articles are not good sources for learning physics.

they say that if our universe resulted to be non-uniform (that is highly anisotropic and inhomogeneous) then the fundamental laws of physics could change from place to place in the entire universe.

This is wrong. The cosmological principle is not a law of physics. It's just a simple assumption that allows us to construct simple models. If it turns out that the simple models don't work, we'll just have to construct more complicated models. But those models will still use the same underlying laws of physics.

And according to this paper [2] anisotropy in spacetime could break the Lorentz invariance [3]

This is a proposed hypothesis that is still in the very early research stage. Way too early to make any statements about its validity.