"Spatial translation symmetry" is what I usually think people mean when they say "physical laws are same everywhere" -- nor is that foolish of me, that's exactly what it sounds like.
> I'm afraid you don't know what you're talking about.
Quoting from the link I posted,
> Noether's (first)[1] theorem states that every differentiable symmetry of the action of a physical system has a corresponding conservation law.
What I said was a simplified rephrasing of that, for someone who apparently did not understand physics.
Jeez. If I even so much as know the term "Noetherian invariant", then I am not totally clueless, even if you disagree about my phrasings.
Get over yourself.
Wait, you are pissed that I criticized this phrase of yours:
> Indeed, properties of spacetime change from one location to another, so one could be inclined in formulating only "local laws of physics", and stating those laws change from location to location according to mass distribution among other things.
That phrasing is either someone who doesn't know physics, or, since you claim to be a theoretical physicist, alternatively it means you are a terrible writer.
> "Spatial translation symmetry" is what I usually think people mean when they say "physical laws are same everywhere" -- nor is that foolish of me, that's exactly what it sounds like.
The thing is, it's not meant to be an insult --you literally don't know what you're talking about (or you're trolling). When we talk about symmetry, we mean a symmetry of the Lagrangian (density) that describes the system.
The Lagrangians everybody write down a priori assume that laws of physics are same everywhere.
The spatial symmetry for example just means L(x, v, t) = L(x', v, t) where x and x' are different by a small amount. An example of this in the classical context is a flat space-time with no potential (U = 0) everywhere. This just means the space "feels" the same everywhere (that is, there are no forces), which in turn means momentum will be conserved (due to the form of the action). This doesn't mean we have proved the laws of physics are same everywhere. That's an assumption we had from the beginning when we wrote down the Lagrangian.
Lack of spatial invariance in realistic systems doesn't also mean "laws of physics depend on where you are". Again, we always assume that it is true; the broken spatial symmetry just means there is a non-uniform field.
And the term that you proudly "know" ("Noetherian invariant") doesn't exist, so I wouldn't hurry and say "you're not clueless" about what you're talking about. You might wanna read that Wikipedia link you gave.
Since you're a theoretical physicist (which you didn't originally sound like), and I'm not, that would presumably mean you know a lot more about the subject than I do.
Further, my past experience is that physicists tend to frequently misunderstand physics that is outside of their own narrow speciality, so since you're more interested in being insulting than in educating, I can assume nothing about your supposed superior understanding. Seems like just ego.
Well, educating random people on the internet in physics is not my job.
I was just pointing out to a piece of misinformation before someone takes it to be true. And again, it wasn't meant to be an insult, I literally meant it and it is true --you literally didn't know what you were talking about. I only meant to state a fact. There's no need to make this something personal. For what it's worth, I'm sorry if it offended you.
In my view, not knowing things is not something bad. You can always learn things. But spreading misinformation about something you don't know (and insisting on it) is not.
> Further, my past experience is that physicists tend to frequently misunderstand physics that is outside of their own narrow speciality
???
Are you talking about physicists (faculty), or students?
Physics is a lot more connected than you think, and I haven't yet met a single physicists who doesn't know undergrad-level classical mechanics.
Edit: After reading your reply, I take that "sorry" back. For me, you're not someone worth spending even single second for. You can take this as an insult if you think otherwise.
On the one hand you say educating is not your job, on the other hand you are very concerned about misinformation -- which is a matter of education.
You thus contradict yourself for purely rhetorical reasons.
Worse yet, saying "you are wrong" is not correcting misinformation for the sake of onlookers. You need to tell them why -- which you failed to do.
I don't think you interpret English very well, and certainly you don't explain well, so it's impossible to see whether this is an area of physics you actually know or not.
So far, I am doubting that you understand this area well enough to correct others. All I see so far are two beside-the-point nitpicks.
Explain physics or stop kvetching. If it's not your job to explain, then it's unhelpful to say "you're wrong but it's not my job to explain!" Fish or cut bait.
"Spatial translation symmetry" is what I usually think people mean when they say "physical laws are same everywhere" -- nor is that foolish of me, that's exactly what it sounds like.
> I'm afraid you don't know what you're talking about.
Quoting from the link I posted,
> Noether's (first)[1] theorem states that every differentiable symmetry of the action of a physical system has a corresponding conservation law.
What I said was a simplified rephrasing of that, for someone who apparently did not understand physics.
Jeez. If I even so much as know the term "Noetherian invariant", then I am not totally clueless, even if you disagree about my phrasings.
Get over yourself.
Wait, you are pissed that I criticized this phrase of yours:
> Indeed, properties of spacetime change from one location to another, so one could be inclined in formulating only "local laws of physics", and stating those laws change from location to location according to mass distribution among other things.
That phrasing is either someone who doesn't know physics, or, since you claim to be a theoretical physicist, alternatively it means you are a terrible writer.
Neither is a reason to get rude with me.