The h Bar

Stan Shunpike

12:01 AM

@0celo7 what book was the problem in for calculating the length of the day?

0celo7

@StanShunpike No book, doing this on my own.

Stan Shunpike

That's sick. How did you approach the problem?

Like awesome sick

If that wasnt clear.

0celo7

@StanShunpike You're giving me WAY too much credit. I just showed that GR is really weak on the surface of the Earth and 24 hours is both proper and coordinate time.

I got a really weird answer in a consistency check where I mistyped something, so I mentioned it.

Stan Shunpike

Maybe I'm just easily impressed by down to earth stuff lol. I get a real kick out of any prediction that can be made from complex theories that actually relates to stuff in my daily life

0celo7

12:37 AM

@ACuriousMind So I solved the geodesic equation in the Newtonian approximation and got...Newtonian mechanics. Really underwhelming.

Also right click doesn't work in chat anymore.

ACuriousMind

@0celo7 lol. then again, what did you expect?

What should right-clicking in chat do?

0celo7

@ACuriousMind It should let me correct underlined words.

Restarting Chrome did not work. Weird.

ACuriousMind

Oh, you people and your weird spellcheckers

Learn to write without crutches :P

0celo7

@ACuriousMind It was a whole lotta work for $v=\sqrt{GM/r}$.

Then again, the centripetal acceleration expression is no laughing matter either.

Stan Shunpike

There just isn't enough space on my phone for physics books and music. They are constantly battling for space. I'm either gonna have to remove Kaku or Handel.

0celo7

12:41 AM

@StanShunpike Phone? I have an iPad for reading.

Stan Shunpike

Doesn't hurt to have some on there in case I don't have it handy.

I got the only gold badge that doesn't take actual work lol

@0celo7 So are you done with Wald? Like I mean, have you move beyond it in your GR studies?

0celo7

@StanShunpike For the most part, yes. I skipped some sections that I will eventually go back and read.

ACuriousMind

@StanShunpike Electorate doesn't take that much work, either

0celo7

I have acute self study ADD.

Stan Shunpike

@0celo7 Have you supplemented your GR studies by reading differential and Riemannian geometry books? or are you like @ACuriousMind and can just soak in stuff from non-book sources?

@ACuriousMind True, but I don't read enough questions to do that and I also don't want to just randomly upvote because that obviously would be idiotic.

0celo7

12:49 AM

@StanShunpike I learned a lot of diffgeo from Straumann. I have also read swaths of Fecko and Hawking.

Fecko is pure math I guess.

ACuriousMind

@StanShunpike Just saying. I didn't want to encourage to you vote randomly.

0celo7

If I was truly motivated, I would sit down and digest large parts of Jost and Lee.

But, alas, I'm not (that masochistic).

Stan Shunpike

How long have you had Straumann? I am considering getting it. But unfortunately the library copy wasn't there so I haven't been able to look through it yet.

0celo7

@StanShunpike Since sometime in November/December.

Stan Shunpike

Is Fecko good? Some of the reviews made it sound like its written poorly.

0celo7

12:54 AM

@ACuriousMind Has it on his queue I think. He might be kind enough to give it the 3rd party once-over for you.

@StanShunpike It's meh.

I wouldn't spend the money on it if I were you.

(There's a reason it's Cambridge and not GTM.)

Stan Shunpike

Lol

0celo7

(That reason being the GTM editors would have annihalated it.)

ACuriousMind

@0celo7 It'll probably be at least a month before I get to it. And then it's semester again, and I probably won't get to it, then. I'm a lazy bastard.

0celo7

Some sections are worth reading if you can somehow get ahold of it.

@ACuriousMind I understand, but think of the children.

Stan Shunpike

Which Hawking book do you have?

@ACuriousMind Laziness evidently must be relative.

Does Hawking have more than one serious book?

0celo7

12:58 AM

@StanShunpike If the sentence "An $n$-dimensional topological manifold $M$ is a topological Hausdorff space with a countable base, which is locally homeomorphic to $\mathbb{R}^n$" means nothing to you, Straumann might be too much.

Kyle Kanos

@dmckee Still hasn't gone anywhere. If you want to pull out your fame and help git'r'dun, that'd be great!

Stan Shunpike

I understand that :D

Music to my ears compared with how MTW write

They don't define things! At least not like Wald

0celo7

@StanShunpike "Let $A$ be a commutative, associative, unitary $\mathbb{R}$-algebra and let $E$ be an $A$-module."

Stan Shunpike

75%

dmckee

@KyleKanos Hmm ... I had already voted for that and for Qmechanic's related post. But there just doesn't seem to be enough love to move it onto a priority pile.

Come on, h-barians! Lets see some meta love!

ACuriousMind

1:04 AM

Voted for both already

0celo7

@StanShunpike You're probably fine.

Kyle Kanos

@dmckee Yeah, it'd probably only be useful on the sciences (which is what, 6 sites now?)

ACuriousMind

We have friggin' xkcd oneboxing.

Kyle Kanos

Or more

stackexchange.com/sites#science-questionsperday

dmckee

Hmm History of Science and Mathematics, Computational Science, Space Exploration, Computer Science gotta be a few more

ACuriousMind

1:06 AM

So arXiV is definitely not too "niche" to ask for.

dmckee

What is the shorthad for theoretical computer science, anyway?

Kyle Kanos

Isn't it CS.SE?

Nope, CSTheory.SE

dmckee

Ah. Too easy for me. I like this complicated.

Lower case, and in square-brackets.

[ abbrevaiation.se ]

Kyle Kanos

@dmckee does that work for links?

dmckee

Physics from "physics.se" in square brackets and so on.

Kyle Kanos

1:13 AM

Interesting set of statistics: we apparently have had less questions, more answers, higher % answered, less users, more daily visits, and less questions/day than Cross-Validated (looking here: stackexchange.com/sites#science-questionsperday)

@dmckee I see, I never knew that

Physics

what the

got it

0celo7

@ACuriousMind If I assume the Newtonian limit when deriving the time dilation of the ISS, do I have to solve the geodesic equation or can I just assume that Newtonian velocity equation holds?

dmckee

Works in comments on the QA site and meta, too.

0celo7

I know that I can, I'm just wondering if I should.

Kyle Kanos

@dmckee What about for write-your-own close votes?

ACuriousMind

@0celo7 Uh, I'm not sure. Sounds like it'd be okay, but it's probably handwaving

0celo7

1:16 AM

@ACuriousMind Taking X limit is handwaving anyway.

dmckee

@KyleKanos Uh ... I would assume so, but haven't tried it.

I mean, you'd think it would get posted as a regular comment, right?

Kyle Kanos

It does turn into a regular comment afterwards

But I wonder if there's something screwy with it just because it's a close vote thingy

0celo7

Perhaps I should calculate it without assuming the Newtonian limit.

Then I get to use vielbeins!

@ACuriousMind Does it bother you when people say vielbeins?

ACuriousMind

@0celo7 A bit, yes, but Vielbeine also sounds stupid.

0celo7

@ACuriousMind polytrad sounds even worse.

Besides, what would the string theorists be without their elfbeins?

ACuriousMind

1:20 AM

@0celo7 Sounds like an illness: "Yesterday, I got polytrads" - "I hope you get better"

0celo7

Ha

Floris

@alarge apologies if I take away opportunities for you to answer a question... there's always space for more than one version!

0celo7

@ACuriousMind I found an expression for the angular velocity using the full Schwarzschild metric. I'm gonna be accurate to like 20 decimal places now.

@ACuriousMind Do you think it is acceptable to simply refer the reader to a book for Christoffel symbols?

ACuriousMind

@0celo7 Depends on who is intended to read it, but yeah, noone wants to see those ;)

Sean

1:36 AM

Woah, I didn't know @Floris came on here!

Also, I have a question for the mods/ high rep users that I wanted to float on here before I ask it on meta

0celo7

@ACuriousMind Can I use $R_\oplus$ for the radius of the Earth? Nvm, I can.

dmckee

@Sean I always have an answer, but sometime it's "Beats me.".

ALso, I charge for correct answers.

ACuriousMind

@0celo7 I have no idea what that symbol means

0celo7

@ACuriousMind Cause you're not a GR nerd.

ACuriousMind

1:53 AM

@0celo7 That's not GR, that much I know!

Astrologer! Leave me be!

0celo7

@ACuriousMind I'm saying a true GR nerd would know this because he has done calculations using the Earth radius.

@ACuriousMind Dimensional analysis sucks. I am missing factors of $c$.

Sean

@dmckee first there's a pre-question. You know that banner that shows up on resource recommendation questions? Does that auto populate on any question that is tagged with "resource recommendations" or is that added manually by a mod?

dmckee

@Sean Er ... I think we have to add them, but Qmechanic is usually really quick about it.

Sean

Ok here's my real question: why don't we have a banner like that for homework questions?

Can I ask for that on meta as a feature request or is there some kind of technical reason that wouldn't work?

0celo7

@Sean Homework = quickban and added to @ACuriousMind's shitlist.

dmckee

2:05 AM

We certainly have several kinds of banners we can add.

Stan Shunpike

Lol so true

@0celo7

0celo7

@ACuriousMind Crap. Why does \align give me an equation number for each line?

Stan Shunpike

add * to it

dmckee

Hmm ... I've never thought about that.

0celo7

@StanShunpike That gives me no numbers.

dmckee

2:06 AM

The homework policy has been in flux so often that have one would probably have caused a lot of strife.

0celo7

I want one number for the two lines.

dmckee

Maybe it is sufficiently settled to consider now.

Stan Shunpike

Oh, I see

dmckee

There is, however, a fixed number of banners so it could require losing one of the existing ones. Not sure.

0celo7

ACuriousMind

2:07 AM

@0celo7 Put \notag on the lines you don't want a tag on, then

0celo7

That's just dumb.

dmckee

@0celo7 Then use \tag{} on the line you want to have numbered.

0celo7

Cool.

Stan Shunpike

I think its pretty clear this isn't a hw site if you talk to ppl. Some ppl get irritated quickly by it.

ACuriousMind

@dmckee It's better to use \notag to supress tags, because you have to fix the number label with \tag, which can cause problems if you later add equations before that

0celo7

2:08 AM

I used \notag

dmckee

@ACuriousMind I use so few tagged equations that I usually use symbols with them, but I take your point.

Sean

@StanShunpike but that doesn't stop people from asking

0celo7

@ACuriousMind Quick, pick a letter for my orbit parameter!

@all Actually

ACuriousMind

@0celo7 o?

0celo7

@ACuriousMind $dx^\mu/do$ looks...strange.

ACuriousMind

2:12 AM

Hah, I like it

0celo7

$\lambda$ it is!

Stan Shunpike

@Sean its true. Maybe we should just have a banner that says NO HW in big letters

lmao ppl would still do it

NeuroFuzzy

Isn't $do$ used in scattering angles a lot?

"a lot" meaning I saw it in Landau I think

I'm so lazy I ask on chat instead of opening the book on my desk.

0celo7

@NeuroFuzzy $\mathrm{d}\sigma$?

NeuroFuzzy

$d\sigma$ being the effective cross section element $do$ being a solid angle element (I opened the book)

ACuriousMind

2:22 AM

@NeuroFuzzy The solid angle element is $\mathrm{d}\Omega$! Which sort of heretic are you reading? ;)

0celo7

@NeuroFuzzy Crazy notation. $\mathrm{d}\Omega$ is what normal, well-adjusted people use.

ACuriousMind

Oh, you said it, Landau

0celo7

@ACuriousMind I need to watch less YouTube while writing my manifesto. I don't even need the geodesic equation, I can just vary the Lagrangian directly.

I only need one of the equations anyway.

Based Killing conservation laws.

Stan Shunpike

@0celo7 Is your manifesto going to be part of your Nobel speech?

Which I gather Sofia is now granting apparently so good luck with that. She self proclaimed earlier

0celo7

@StanShunpike No, I'm trying to do the time dilation of the ISS without spending 5 pages solving Schwarzschild geodesics.

NeuroFuzzy

2:32 AM

@0celo7 is that the thrust of your paper?

0celo7

@NeuroFuzzy I mentioned to my physics teacher that I knew how to do it, so I figured I should do it.

@NeuroFuzzy I'm not going to take the Newtonian limit like most people do, however.

Stan Shunpike

Is that the one who couldn't do integrals or was that your math teacher?

ACuriousMind

@0celo7 What function does "based" fulfill in that sentence?

0celo7

@StanShunpike My math teacher has never heard of line integrals.

@ACuriousMind American teenager slang.

@StanShunpike My physics teacher is a Princeton grad and almost got a math degree.

bolbteppa

Any of you guys ever seen loop equations?

ACuriousMind

2:38 AM

@0celo7 And what does it mean? Something good or something bad?

0celo7

@ACuriousMind Uneducated peasant...

Basically, it means "awesome".

NSFW Haha holy crap gyazo.com/46b25008dd97d17794884d1344dbf7d1

NeuroFuzzy

HAHaahahh @0celo7 do you know if that's supposed to be the first reference? I kinda only heard of it in the last six months or so. Year tops.

er, I think that's a bit much for a .se chatroom

0celo7

@NeuroFuzzy NSFW tag.

Hence why I didn't copy the link and embed it.

ACuriousMind

@0celo7 You people are weird.

0celo7

@ACuriousMind You were once my age.

ACuriousMind

2:42 AM

@0celo7 Oh, yes. I...don't miss it, really ;)

Stan Shunpike

@0celo7 @ACuriousMind "based" according to urban dictionary means "Having many girls, being a mansion, swagging to the maximum, and looking like jesus"

0celo7

@StanShunpike Killing is def a swag king.

ACuriousMind

@StanShunpike Yeah, I preferred not to comment on how that can be applied to the geodesic equation

Also, I chose not to ask what "being a mansion" means.

NeuroFuzzy

@ACuriousMind isn't it obvious?

0celo7

@ACuriousMind Fun fact: circular Schwarzschild orbits are identical to Newtonian ones.

ACuriousMind

2:44 AM

@NeuroFuzzy The general meaning, yes, but there might be subtle nuances that elude me

0celo7

Turns out not taking the Newtonian limit does absolutely nothing.

ACuriousMind

@0celo7 I think I knew that.

0celo7

@ACuriousMind I did know that, but only remembered it after much grunt work.

I got to $$\frac{\mathrm{d}\phi}{\mathrm{d}t}=\sqrt{\frac{B'(R)}{2R}}$$ and I had this feeling of dread.

It's just $\sqrt{GM/R^3}$.

ACuriousMind

Oh, well. Now you know for certain that you can take the Newtonian limit ;)

0celo7

@ACuriousMind I have determined that I have to calculate more Christoffel symbols in the Newtonian limit, because the Killing conservation laws don't hold exactly.

I have to calculate two more, to be precise. (one of the two vanishes identically)

bolbteppa

2:48 AM

How about 'correlation functions for connected components'?

0celo7

Killing conservation laws look more impressive though.

@bolbteppa Perhaps. More context?

@bolbteppa What is a loop equation anyway?

bolbteppa

"Loop equations of matrix models express the invariance of the models under field redefinitions", I think they are the exact same as the Ward identities but for matrix models

0celo7

@bolbteppa Matrix models?

WZW models?

bolbteppa

If you try to solve a path integral where the argument of the exponential is a crazy matrix

Does anything in (3.3) or (3.4) on page 7 of this arxiv.org/pdf/1209.3984v2.pdf look familiar, it would be a MASSIVE help!

I think it's very similar if not the exact same as the stat phys cluster expansion stuff but I never went through it fully tbh

ACuriousMind

@bolbteppa Well, I don't know this stuff, but the title of that section is "non-perturbative Ward identities", so it seems your idea about WI is correct.

Sofia

3:02 AM

@StanShunpike I believe that I made a mistake, I meant i.g. Nobel prize (or e.g. I am not sure on the 1st letter). But if someone discovers that entanglements are a local phenomenon, that deserves an immediate letter of recommendation to Stockholm.

Stan Shunpike

@0celo7 have u used Landau? I'd ask @ACuriousMind but he doesn't read books :p

0celo7

@StanShunpike Nein

Sofia

@0celo7 what is Ceres? I heard of the 10th planet but I am not sure and I don't know its name.

0celo7

@Sofia Off the top of my head: a moon

Off the top of google: not a moon

:D

NeuroFuzzy

A tenth planet??? So they found a ninth?

0celo7

3:06 AM

It's the dwarf planet between Mars and Jupiter.

bolbteppa

How about Seiberg Witten equations? I think it's just EM equations or something

Stan Shunpike

@bolbteppa lol are these topics in a book? An article? A variety of sources?

bolbteppa

Loads of places haha

Stan Shunpike

Lol serial googling

@ACuriousMind so if you don't read books, does that mean you don't read fiction?

ACuriousMind

@StanShunpike No, I'm an avid reader of Sci-fi and Fantasy books

Stan Shunpike

3:14 AM

That's cool.

bolbteppa

If you had a correlation function $<V_1V_2> = Z = \int[d\psi]V_1V_2 e^{i\int \mathcal{L} + aJdx}$ it makes sense that $\dfrac{d}{da} \ln Z = \int[d\psi]JV_1V_2 e^{i\int \mathcal{L} + aJdx}$ right?

Stan Shunpike

My serial googling is slightly less intense than @bolbteppa I found the following. Albert Einstein invented a theory about space....and it was about time too.

bolbteppa

@StanShunpike conformal field theory ;)

Stan Shunpike

:p haha

That stuff is awesome. Was it you who told me about the water droplets? That was crazy awesome

bolbteppa

I missed the $\dfrac{1}{Z}$, it makes sense now

Yeah, but honestly that was more statistical mechanics math.ucr.edu/home/baez/renormalization.html

@StanShunpike one thing you could try to do is to solve the 3-D Ising model ;)

Stan Shunpike

3:23 AM

@bolbteppa im up for it. Okay, where do I find info on how to do that? Wait wait let me guess Landau? Always a safe bet.

ACuriousMind

@StanShunpike lol, he gave you an unsolved problem, do you know that?

Stan Shunpike

No, never heard of it

LOL well, I've never been one to back down

But I might make an exception

@bolbteppa tricky Lol

Next time I'm googling stuff before I open my mouth lolol

dmckee

@StanShunpike When a supervisor give a student a unsolved problem he (or she) usually doesn't expect a breakthrough solution, but rather is interested in how you tackle it.

Full steam ahead.

Heck, I had a professor offer one as a bonus problem on an exam.

"Solve, as well as you are able, the generalized, three-body central force problem. 10pts."

10!, Just 10! Arghhhhhhhhhh!

infinitesimal

:D

NeuroFuzzy

@dmckee what level of class? That would actually be a bit fun... usually when I hear 'unsolved problem' I turn around and walk away.

dmckee

3:33 AM

Undergrad mechanics. Out of Marion and Thornten.

Stan Shunpike

@dmckee well, maybe I'll give it a go. Nothing to lose and lots go learn.

NeuroFuzzy

Oh. So that's about the same level of class whose take home final is sitting in front of me.

dmckee

I assumed $m_2 \ll m_1 \ll m_0$ and exhibited a couple of possible solutions with first order perturbation and got a few points.

ACuriousMind

@NeuroFuzzy I'll never get the American system... take home final?

NeuroFuzzy

@ACuriousMind it's a rarity, this is the first course I've ever had with one.

@ACuriousMind & other people I've told have been surprised too.

@ACuriousMind professor's choice! And I don't mind one bit since classical continuum mechanics stress tensors are on it.

Stan Shunpike

3:38 AM

@ACuriousMind its an idiotic concept isn't it? Completely defeats the point of a closed book exam.

ACuriousMind

@NeuroFuzzy Heh, well, I don't think I'd complain either. It's just weird

NeuroFuzzy

@StanShunpike hey, that's my prof you're talking about! :P

dmckee

@ACuriousMind I only had two of those as an undergrad. One was the harder test I've ever taken excepting only my grad-school comprehensive exam.

Stan Shunpike

@NeuroFuzzy lol well, maybe he designed it to be open book and open Internet lol

Or shs

She*

dmckee

@StanShunpike This. If I let you use a lot of references and time it is fair to ask hard questions.

Stan Shunpike

4:36 AM

@bolbteppa @ACuriousMind so the Ising problem is NP-complete?

bolbteppa

idk what np complete means tbh

Stan Shunpike

Nor do I. But that's part of a challenge.

:D

Maybe I need to try the comp sci chat lol

dmckee

NP is a set of computing problems which can not be solved in polynomial time.

That means they scale very badly.

NP-complete is a select group of these that are equivalent to the traveling salesman problem.

Stan Shunpike

What is polynomial time? That's the part of the def I always get confused bym

By*

dmckee

Polynomial time means the expected (or maximum, depending) time to complete scales by a polynomial function of the size (usually $N$) of the input.

NP problem scale by exponentially or factorially or other bad ways.

Stan Shunpike

4:40 AM

And the NP-complete problems scale exceptionally badly?

dmckee

Nice problems are one that scale slower than $N^2$.Binary searches are $\ln N$. Linear searches are $N$. Good sorts are $N \ln N$, mediocre sorts are $N^2$. Inverting a matrix by gaussian elimination is $N^3$.

@StanShunpike Yep. The worst class known.

I think its the worst. I'm not actually a specialist in the area, so what do I know.

Stan Shunpike

So classifying problems as P or NP or NP complete is useful because it's like effectively ruling out what kinds of solutions / computations are going to be feasible ?

@dmckee ^

dmckee

Partially.

There are actually pretty good approximating methods for NP_complete problems for small to modest sizes.

But the approximation exhibit an abrupt change from pretty good to nearly useless at some size.

There is an intersting theorem that shows that all NP-complete problems are isomophic with one another, and some other that show that problems can be transformed in certain ways such that the solutions also transform neatly.

The CS guy have a ball with this stuff.

Stan Shunpike

lol I can tell. It sounds really interesting but very abstract, even compared to physics lol.

You wouldn't happen to know a good introductory book on the subject?

David Z

5:14 AM

@StanShunpike if you don't get answers here (which you may not; it's not something physicists concern themselves with in general) that would be a good one to ask the CS chat

Stan Shunpike

@DavidZ Thanks, just tried it. I hope to hear back! This all started with @bolbteppa challenging me to try to solve the 3D ising problem or something. So I read an article on it and found out it's NP or NP complete or something like that. And so I decided to learn more about it.

@DavidZ which chat do you recommend? I tried Theoretical Computer Science and Programmers. SO seemed to have rooms for individual languages and this didn't seem like it fit into that kind of a chat

David Z

Look in Computer Science chat, or perhaps one of the rooms on chat.stackoverflow.com (I believe there are many more than just language rooms)

It'd be too introductory for Theoretical Computer Science

You could also see if Computer Science takes resource recommendation requests

Stan Shunpike

@DavidZ That's a possibility. I have in general avoided asking for resource requests on SE in general since (1) they don't seem to be well received all the time and (2) they do seem well received in chat. I wasn't aware of the Computer Science SE. That's a good one to try.

Physics Meta

7:20 AM

0

Q: Reputation Banking

Let us say that we have a user who has insufficient amount of reputation so as to put a bounty . Can we have a system or what are the pros and cons of a system which facilitates borrowing and lending of reputation ? The lenders of reputation can be repaid in a certain fixed time interval by the b...

feature-request

user54412

7:57 AM

@ACuriousMind Take-home exams were the best part of my undergrad curriculum -- I mean, they were generally long and hard, but the ability to make them long meant they had interesting questions. No multiple choice, no memorization, no plug-and-chug with basic formulas.

user54412

In fact, it was a faculty board resolution that all finals should be take-home.

user54412

That said, they are extremely rare in the US -- most schools don't trust their students, and most students don't care about learning so much as getting good grades.

user54412

@0celo7 What else could they possible be? :P Circles are circles, and spherical symmetry means they have to progress regularly in angle. Plus, the mass parameter M for Schwarzschild is defined to be that which you measure based on orbiting the body so that the results are sensible.

Stan Shunpike

@ChrisWhite Also, Caltech exams are hard enough, even if you cheat, you might still fail :p haha. Just kidding, honor code rules.

/rocks

/is awesome.

Sofia

@NeuroFuzzy : Mercury, Venus, Terra, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, = 9 in all. The 9th is Pluto.

user54412

8:10 AM

@StanShunpike The hardest exam I ever took was unlimited time (well, a full week), open any textbook, open notes. No resources could help anyway.

user54412

@Sofia The International Astronomical Union, for better or for worse, declared Pluto to no longer be a planet a couple years ago.

user54412

Also, at one point in history, several large asteroids were considered planets. In fact, Ceres was a planet before Neptune.

Stan Shunpike

Really? I never knew that. Wowzers

user54412

Indeed -- the whole "we're discovering too many objects like this, let's not call them all planets" thing is a repeat of history

Stan Shunpike

Yeah, I just read some quote that the idea of a planet is more of a cultural thing and that we priortize certain celestial objects so that we can focus on a few. A bit of an exaggeration but I think that general point has merit. Too many planets and people would be confused.

Physics Meta

8:16 AM

1

Q: can we get some mobile version of the related questions box / panel that I find on SE on my laptop web browser?

I spend most of my time on my mobile and do most of my SE stuff on it. I chat, I ask, I comment -- all of it on my mobile. But when I try to decide whether to ask or answer a question, I unfortunately don't have any way on my mobile to see if there are related questions already on SE. Sure I can ...

feature-request

infinitesimal

8:37 AM

Including "planet Hollywood" :D

Stan Shunpike

9:21 AM

@bolbteppa Gelfand has his own theorem?en.m.wikipedia.org/wiki/Gelfand–Naimark_ theorem what a stud!

Damnite

en.m.wikipedia.org/wiki/Gelfand–Naimark_theorem

Sofia

@0celo7 I knew that between Mars and Jupiter there was a planet which exploded. Can you tell me if smth. like this is known to you?

Stan Shunpike

@infinitesimal lol people fron Hollywood sometimes seems like they live on another planet

Sofia

@ChrisWhite Very interesting! Thank you.

@StanShunpike I don't have the money that those movie stars have, but I don't envy them. All the time torn between impresarios, all the time cosmeticians to make them look young, all the time intrigues and concurrence with other stars. This is not life.

Stan Shunpike

I agree. Not to mention like how crazy it makes u go inside. So many do drugs.

@infinitesimal

Lol a love for physics is a much healthier drug

:D

Sofia

9:54 AM

@innisfree I have difficulty to discuss with people that offend me. I asked smth. very natural, to withdraw the "failure degree" you gave me about understanding non-locality. But, leaving aside the minimum respect that I ask, assume that I'd stay with the offense: logically, if I don't understand non-locality, how can you have at all a conversation with me on the topic? How can you discuss integrals with someone that doesn't know simple algebra?

@innisfree Of course the issue has to be discussed, but under your assumption that I don't understand locality, how can we have a talk?

innisfree

10:09 AM

@sofia, I'm deleting all comments from my exchanges with you. Your antics are very childish (but fortunately uncommon on the site). I will try to avoid all similar interactions in the future on this site - I hope they remain a rarity.

Sofia

11:40 AM

@innisfree then, welcome to a friendly talk! Are you in the site now?

@innisfree for making the conversation more economical in time, let me tell you, simply, what I know. So: we have two particles, at enormous distance from one another. No apparatus of measurement influence, the particle in the other lab. As to the particles, no interaction known to us exists between them at such distance. And though, we have the correlations. (I continue)

@innisfree now, as we say in our site "show some effort", let me tell you what we tried until now: 1) Local Hidden Variables - Bell's inequalities - are violated. 2) NON-local hidden variables - faster-than-light signals - Bohm's interpretation - DOESN'T work, more exactly is at odds with the relativity.

@innisfree if you can, let's have our talk, I have endless things on my head.

0celo7

12:56 PM

@ChrisWhite I remembered that after calculating all the Christoffel symbols and solving the geodesic equation. I have also seen $M$ defined as $P^0$ in the ADM sense, which I personally like better.