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majorpickle01 t1_j292333 wrote

In short, yes.

In not short, there are some more fringe theories coming out of quantum mechanics that posit that the speed of light (or more specifically the speed of causality) has changed slightly over time. However I've never seen anything serious come out of such papers.

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_PM_ME_PANGOLINS_ t1_j29nz9i wrote

There’s nothing we’ve found that says it has to have the value that it does, or that it can’t change at all, so it’s not completely out there to investigate the maths of if it did change over time and whether that predicts anything measurable.

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majorpickle01 t1_j29yae1 wrote

I don't think it's out there at all and it could be a fascinating avenue of research haha. I wasn't trying to be dismissive - I just know there's been a few papers put out speculating on a changing value of speed of causality, just I don't think there's been enough evidence or testability to really "mean" anything scientifically

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CompactOwl t1_j2ba062 wrote

My level of physics is limited to what I understand on the side because of my math major, but I have a question:

If speed of causality changes, would we even be able to measure that? Or what the change in causality cancel in all of our measurement instruments to give the same result again?

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majorpickle01 t1_j2bvhwy wrote

from the very limited reading I've seen into the subject the idea is it would be detectable in the CMB - something along the lines is it would affect the distributions of bands or something like that.

If you do some digging for papers on it there's are suggestions on how to test for it / physical consequences

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Agreeable_Highway_26 t1_j2aaj2n wrote

If it did change for E=mc^2 to hold AND conservation of energy to hold would there not need to be a large change in the amount of mass in the universe?

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majorpickle01 t1_j2ab6qi wrote

Admittedly I wouldn't be the best person to ask as I haven't studied science in nearly a decade, but my uneducated educated guess would be a change in the value of c is balanced out by other factors, probably something to do with dark energy.

In a sense the changing rate of expansion of the universe due to dark energy is what is causing the change in c. But that's just 100% made up of the top of the bonce. Hopefully someone with a more advanced and recent education can give you a good answer.

Key point is things don't change just because. There's always a reason fundamentally

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