> O vzn You are implying I've been annoying? Welp, I agree, but I will continue to stand behind my opinion until someone gives me a reasonable argument to think otherwise. O Emilio Pisanty did that and I listened to his advice.

One rule I really don't like in classical logic:

$A \implies B$

Responsible for got knows how many miscommunication and misconceptions between two people when their brains tried to guess what's the remaining message given highly noisy and limited data

It is found out in a 2018 discussion and logic class that one of the main contributors why sometimes I am incomprehensible is because my thinking basically lacked this rule most of the time

and instead, it is replaced by $A \implies (B \implies \bot)$, which in English "Do not try to assume, predict, guess or otherwise if any, subliminal, implied, hidden etc. message of the other person" and always ask for clarification

(I might have got my logic symbols wrong, still not very good at formal logic...)

The consequence of this is unless I have seen the same thing umpteen times, the person pretty much have to spell out the whole thing exactly since I will not try to assume what I understood from the person

You know I should compile a list of "tricks" for GR computations

I'm sure it already exists somewhere but there's a lot of little things that help out to compute quantities

Like what the Christoffel symbols look like if the metric is diagonal, if components of the coordinates $x_i$ are independant of $x_i$, etc

For instance for the Morris-Thorne static metric, $g_{tt}$ is independant of $t$, $g_{ll}$ is independant of $l$, etc

The metric overall isn't independant of those quantities, but this gives a lot of simplifications

Hi! A moderator commented that I should edit an answer to my question to make it complete, if I could improve it in that way. I tried to to improve it, but it seems to have been rejected: "This edit deviates from the original intent of the post. Even edits that must make drastic changes should strive to preserve the goals of the post's owner."

It's a really good answer, and I would like to complete it, or see it completed. I would be thankful for any hints on what I should improve in the edit.

@Tellus It wasn't fully rejected, suggested edits require 2 votes in either direction. I rejected it because I don't think it improved the answer any. I probably could have gone with a different standard rejection reason, but went with that one.

It seems to me that dale does answer the question, but you just want to add more details. If that's the case, either leave a comment or post your own answer.

@KyleKanos The answer deals with the question posed in the title, but not the other two questions posed in the actual question text, which are very related. Do you think these supplementary questions are bad? That they're not worth the lines required to answer them?

Personally, I think the question itself is crap and should have been DV'd and probably closed.

Note also that I'm far more stringent when it comes to suggested edit queue, rejecting just under 40% of all edits over reviewed.

You're probably right, I have virtually no knowledge of physics (one high school physics course, but I want to learn more). That's why I asked in the first place - I wasn't comfortable figuring this out on my own, and I thought the topic would be at least on par with a simple homework problem. I don't think I asked the question too well either, it looks strange.

All I wanted was to elicit answers to both questions (did they change, and exactly how much). I still don't understand how I would have to proceed to do that. If I asked them separately, they would probably be closed as duplicates. When I asked them together, thinking they're related enough, the community seems to want to ignore the second question. Am I even at the right site? Is there an applied physics site? ;)

There was a proposal to have an applied physics site, but lack of interested users killed it, I think. That and the fact that applied questions are allowed on this site

hey hyle

kyle

sorry :p

@KyleKanos hey ?

@KyleKanos how come? I consider most people are far more interested in applied physics than theoretical physics, though I am the exception.

@Reign sorry, I'm at work so my attention isn't fully here.... What's up?

@CaptainBohemian I think most users of this site are of the theoretical variety/background. There's a few Meta posts lying about for more background

I am good thanks you ?. I just wanted to ask some questions about the computational astrophysics @KyleKanos

@Reign I can try answering, but I haven't touched comp astro in like 4 years.

I see.. it's okay. I just actually wanted to ask about some project ideas for cosmology -coding projects that I can do. I really like cosmology and coding so I want to do something @KyleKanos

I can only think something like Ned's cosmology calculator but I need to do something more complicated

Yeah, cosmology want something I covered terribly deeply.

If you are allowed, you could grab some existing code (e.g., Gadget) and do some galactic collision simulations

Early universe nucleosynthesis might not be too bad, mostly just solving a series of coupled ODEs, given some initial conditions and transition rates.

Those are nice ideas @KyleKanos

I ll think about them, you said galatic collisions and something came to my mind

Is it possible to some simulation, btw I am in undergrad, to take DM,dark energy and some other values as initial condiitons and create a simulation for bigger structure in our universe ?

* to do

Early universe nucleosynthesis like how ?

thanks btw :p

@Reign yes, I think the Enzo project can do that

@Reign like say you have population of hydrogen atoms, given certain temperatures & collision rates, how long until you have n-percent helium atoms? Or how long until carbon forms?

@KyleKanos Its seems complicated I guess its unlikely for to write that kind of code by myself :) but I ll look at it. Its interesting topic.

@KyleKanos I see thats nice actually

Well yeah it's complicated. Took a few dozen PhDs, post-docs & grad students quite some time to write and validate Enzo. No undergrad could do that same thing solo, but you could take the code and run it for a decent project

@KyleKanos I see your point. My teach actually wants me to write some code about something. But maybe I can do something related to that one

teacher

→ 9 messages moved to Trash

@ACuriousMind wow lol

I want to discuss physics too but I am having trouble learning a few physics topics and am not sure how to ask about them either

@Slereah physics.stackexchange.com/q/480068/50583 sounds like something you could be interested in.

@ACuriousMind Hello! I was thinking, can't something like "Smoke-detector" (Charcoal) work on chat too?

I mean, to remove spam automatically?

@SDFG It probably could, but chat isn't flooded by automated spam like the main sites because you need 20 reputation to post anything here, so there's no real need for it

Oh, I see.

Well, I am also working on a small physics project. May be at some point when enough progress gets made and I write something I can also ask for feedback on here :)

That will not be spam right?

since it is physics . . .

@ACuriousMind samuel-lereah.com/articles/Physics/spacetime-gluing

Could be!

I should finish that article

Alas math is hard

So I moved some files around in the library & it's causing issues for other people bc they're too lazy to figure out how to fix the issue (which literally only involves changing the include path)

That just makes me wonder how these people get by in life. I mean, if you can't read a complier error & fix it, what happens when say your dishwasher stops?

@KyleKanos Obviously buy a new dishwasher. (This comment sponsored by MaytagⓇ)

Well I suppose the people I work with can afford doing that

@KyleKanos And that's exactly how big dishwasher wants them to think about it.

But it just boggles my mind how you can read a complier error that clearly says "file X doesn't exist" and not know what to do

@KyleKanos Are they just regular users of the software?

jesus I keep pinging you out of habit but it makes no sense here

They're part of the development team!!

So part of their job is to write & debug C++ code, they should know how to fix these things...I shouldn't have to fix their code bc theirs is dependent on hardcoding crap

Yeah that's concerning. I could understand end users getting an error and saying "I'm not even going to try to deal with that, IT fix this!"... but the development team running into errors is a bit different

I guess maybe it's because governance teams have cracked down on us for changes (bc one guy is an idiot & screwed up big time) and so people are now reluctant to touch things that other people messed with

But it's your system. And you've hard coded included files, so you should deal with the mess of cleaning it up!

@santimirandarp At what precision?

this turned out pleasingly well

@Tellus Since you're on chat - frankly, your comments on that thread were quite a bit past the line of civility. People are here to help, and everybody there behaved perfectly fine, but you were basically trying to bite off the help of anyone who came near you.

@Tellus The answer was perfectly fine, and this comment by the answerer did a remarkable job of showing restraint in the face of unreasonable demands in an unreasonable tone.

@Tellus There is already a good table on Wikipedia, and a good answer that links to it and explains the context. Frankly, including that data in the question is way over on the superfluous side. You need to do your part and follow up on the references provided.

@KyleKanos How come? The question is asking a perfectly legitimate question about physical metrology that isn't covered in the (already quite extensive) material about the topic on the site. The volt really will change*, and that needs to be explored in detail.

* OK, not really. There's two different volts, and one of them is going away, so calibrations do change.

@EmilioPisanty I guess I don't have a good reason for closure, which is why I haven't voted that way. I don't think it's that good a question (seems rushed & sorta written in a "world is in fire" kind of way)