I'm just tossing out thought experiments to those that enjoy themHi,
I think you are talking about the local physics but that's not exactly what i am talking about, when it comes to differences between different localities. I am really talking about the same locality what can change there (as well as somewhere else).
I realize we have to stick to what we know now for the most part, but i also realize we need to keep an open mind about the future. There are still things we dont even have ANY experience with yet because we have not yet encountered them, and even if we did we might not understand them because we had nothing like it in our experience in the past. Remember we are right now basing everything on what we knew in the past, our past experiences. If something comes up that we dont have any past experience to compare it to, we just have to resort to accepting it.
For example, what if we find out that the universe has ALWAYS existed, or the 'multiverse' has always existed. That is, it had no beginning because it did not require one. That would blow our minds because we have no experience to date that deals with something that has 'always' existed with no beginning. If we did find that out, we would be forced to just accept it even if we could not explain it.
I have considered a changing universe before. Consider: There is a scene in the Matrix where the agents change reality (the black cat). Everyone besides the main characters are not aware of the change because they are hard coded into it as well. So it is possible that my past is exactly as I remember it?
I was talking with a Muslim guy one time about God being all powerful. He made a point that we are unable to visualize / understand him because he programmed us.
Just like a computer program only can know what's been programmed into it (machine learning aside), I think the same applies to us looking out into the universe. We are stuck behind the barrier of our own mind.
So this speaks to your point of a changing universe because how would we even know?
Furthermore, frame of reference is critical because in the scope of the universe it is difficult, if not impossible to establish a Cartesian origin. Hubble's law shows that the expansion of the universe is proportional. Even with this now known, there are multiple definition of a day because the reference to the sun is different than the reference to the fixed stars. We barely just discovered parallax and similar phenomena and now that we know about it, a whole new can of worms is unleashed.
I came across one author that proposed that if the universe is expanding than so are we. He went on to say that our bodies and our logal frame of reference is expanding proportionally so even though I am constantly "getting bigger", I cannot detect it because everything looks the same.