The h Bar - 2015-02-25 (page 1 of 3)

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1:31 AM

@ACuriousMind please, don't be hard with him, it's a Chinese - (do you see the red ties?). Let @DavidZ handle the issue. Do they know English? Is he able to read Wikipedia? Please, leave this! You don't know the conditions there (I assume so). China is big. There are regions of terrible poverty. Don't be hard.

@Sofia If they don't know English, they won't understand any answer here, either. If they know English, they can read Wikipedia and ask a more specific question. I'm not harsh, I treat them like anyone else.

1:53 AM

@ACuriousMind Please, be a bit moderate, show some heart. Let DavidZ handle the issue, he works there, if I understand correctly. What you hurry? Please!

2:16 AM

so sof, you say you want the answer to the measurement problem (aka "wavfn collapse"), did you know there is one in the soliton/ fluid mechanics picture?

2:46 AM

@0celo7 hey man, I got a quick question maybe you can help me figure out. physics.stackexchange.com/questions/166937/… I can't tell if I did the problem wrong or the book is wrong.

The problem is I've never handled units like these before and am not sure how to do dimensional analysis for it.

@StanShunpike Should there be a tilde on $x_k$ in the second Eq.?

No! I wondered about that. I didn't see one in the book for the equation they listed. But I went ahead anyways and tried the substitution and I got close. I'm not sure what the tilde was supposed to represent.

Double checking right now

He says they mean the same thing on 26, the previous page.

@StanShunpike Hats mean operators, tildes mean Fourier stuff.

Oh, really?

um...hmmm

@StanShunpike Oh now I see your edit.

In this case, it's both a Fourier coefficient and an operator.

2:54 AM

LOL

okay i just swithced it back and forth lol

@StanShunpike I think the creation/annihilation operators are dimensionless. Which equation has the proper units, yours or the book's?

Well, assume only $\hbar$ $m$ and $\omega$ have units, I got $m\sqrt{s}$ for his equation. It should just be $m$.

I would guess the book is right because my equation makes it look like I have to end up with $\sqrt{m}$ which isn't sensible. At least theirs gets meters to the power of 1.

@StanShunpike Don't use SI units when doing dimensional analysis. Use capital letters that stand for the dimensions, not the units. For instance, for position, write $[x]=L$ or for velocity $[v]=LT^{-1}$.

ooo that's a good idea.

user54412

@tpg2114 My new goal in life: to start a paper with "I shall largely speak of mice..."

3:11 AM

@ACuriousMind After symmetry breaking we get something like $$|D_\mu\phi|^2\sim \frac{1}{2}A^2_\mu v^2-\frac{1}{2g^2}(\partial_\mu A^\nu)^2$$ I've never quite understood how we get $m_A^2=g^2v^2$ from this.

@0celo7 Gauge theory is a conventional mess, factors of i and g are all over the place. Nevertheless, where did you find that? How's the covariant derivative defined that you divide by $g$ instead of multiplying be it?

@ACuriousMind Typo, forgot to include the $F^2/4g^2$.

@ACuriousMind More egregious would be a covariant derivative with the derivative of the gauge field in it.

In my world, $D_\mu = \partial_\mu - \mathrm{i}gA_\mu$, and then the mass term comes out exactly as desired.

@ACuriousMind Aye, but not in some texts.

Ah, these texts probably have a $\frac{1}{g^2}$ in front of the entire action

3:24 AM

In front of the YM part, yes.

If you do that, you have to extract a $\frac{1}{g^2}$ from every term that contains the gauge field so that it becomes a prefactor in front of all the gauge dependent terms, and then, again, you get the mass term as desired

Seems dumb.

You shouldn't think too hard about these factors, it's really a conventional mess.

@ACuriousMind Thinking hard is what wasted an hour earlier.

It's kinda obvious though that the mass of the $A$ has to depend on the coupling.

3:28 AM

I don't want to do that again.

@ACuriousMind By the definition of the Higgs mechanism?

@0celo7 By intuition ;) If you take the limit $g \to 0$, the mass should vanish, because, if the field doesn't couple to the Higgs, the Higgs cannot grant it mass

If the mass doesn't depend on the $g$, that would mean the limit isn't smooth (not even really possible), so you don't have a well-defined theory

@ACuriousMind When we write $\phi=\frac{1}{\sqrt{2}}(v+\sigma(x)+i\pi(x))$, $v$ is the expectation value and $\pi$ is the Goldstone boson. What is $\sigma$ called? $\phi$ is the actual Higgs field, right?

@0celo7 Yep, I think so

@ACuriousMind So what is $\sigma$ called?

@0celo7 The, uh, fluctuation around the vacuum?

No idea, never needed a name for it

3:38 AM

@ACuriousMind So does the Higgs field produce two particles: the "fluctuation around the vacuum" and the Goldstone boson?

@0celo7 No really, since you go to unitary gauge such that the Goldstone boson is "eaten" by the gauge field to make them massive

So Goldstone bosons are unphysical?

It's the longitudinal polarisation of the massive gauge field

No, not unphysical, it becomes a mode of the gauge field

@ACuriousMind The longitudinal mode being the spin-0 state in the spin-1 triplet?

@0celo7 Uh...I guess so? It's the polarisation that's normally declared unphysical by imposing the gauge symmetry upon the Hilbert space (by Gupta-Bleuler, BRST, whatever).

3:45 AM

@ACuriousMind What do you think the longitudinal mode means then?

@0celo7 Well, it's longitudinal - its polarisation is parallel to its momentum

I guess it indeed is the "0 helicity" state that doesn't exist for massless particles in Wigner's classification

Wow, I was right about something...

@ACuriousMind Random other question: what is the definition of $E_8$?

@0celo7 No idea, never worked with it. But I think it simply falls out of the theorem about the classification of Lie groups as a particular Dynkin diagram/root system (don't ask, I can't explain that!)

@ACuriousMind The group theory in Di Francesco is getting really hard. He mentions $E_8$ like I should know what it is.

The only place where I know that thing occurs is as part of the gauge group of heterotic string theory, so don't worry about it.

3:54 AM

@ACuriousMind My goal is to read Becker, Becker & Schwarz.

I have to worry about it.

There's like 100 pages of group theory left to go in Di Francesco. I think I'll have a go at BBS and see how much I'm missing.

I know people who work with electroweak or strong theories every day but have no clue about the group theory of SU(N). One really doesn't need to understand every detail.

I read an article about that E8 thing in Scientific American. Was that the one created (or publicized) by that surfer dude?

user54412

Are you thinking of Lisi?

@StanShunpike Yes, I know who you mean

Yeah, that's the guy

3:58 AM

Don't know the name, either

He likes to rock the t-shirts with the Lie group on it. E8 is a Lie group right?

user54412

"I had gotten lucky by investing my graduate stipend in a little company many thought was going out of business (AAPL), so I decided to go to Maui, learn to windsurf, and work on physics on my own." (Wikipedia on Lisi leaving academia)

user54412

Now that's how to succeed in grad school.

@ACuriousMind I think that's the stand I'm going to take (not knowing every detail). I did learn quite a bit of CFT already. I think I'll read the stuff about group geometry, cohomology and spin bundles in Fecko, then Dine's SUSY book and then some lecture notes on complex geometry. Perhaps that will prepare me.

Have you guys heard of Open Notebook Science? I've never heard of that before.

It says Lisi does it.

4:03 AM

@ACuriousMind Do you think I need to read the fiber bundle chapter? Actually, it's also on gauge geometry, so I might as well.

user54412

@StanShunpike Neither have I.

user54412

I'd like to see someone try to make sense of my haphazard scrawlings.

@0celo7 While, at some point, you should learn about bundles, I've not seen a single bundle in introductory string theory. It's very relevant for non-perturbative ordinary QFT, though.

@ChrisWhite Yeah ikr, mine would be lucky to be considered a scrawl. I actually read a story about a con-artist who impersonated being a doctor. For an entire year, he wrote on patients files just scribbling not actually writing anything. No one ever asked him what he wrote.

@0celo7 What do u usually put in place for Joules?

Like if I use L for meters, what do I use instead of J?

E?

$ML^2T^{-2}$

user54412

4:13 AM

@StanShunpike You should choose a basis for your physical dimension space first, such as M, L, T

user54412

then there is a unique decomposition into that basis

I usually don't put units :D

@ChrisWhite Oh, that's smart. Okay. Cool.

user54412

Random aside: I've started to catalog awesome science/math/other papers/talks/whatever that I've come across. Things that are really forward-thinking (even if only in retrospect), novel, insightful, or beautiful. Anyone have personal suggestions to add to such a list?

@ACuriousMind TFW "introductory" string theory is really freaking difficult.

I don't think BBS is introductory though. Tong doesn't consider it introductory, for whatever that's worth.

4:19 AM

Haven't read it, can't tell

@ACuriousMind BBS has fiber bundles...

That's two errors in recent memory...

(I've been worshipping a false god.)

I haven't said anything about BBS, I just said I haven't seen bundles in introductory string theory. That statement simply can't be an error ;P

I get the feeling your string theory is on par with your GR...

@0celo7 I'm not debating that, I just had my first course on it this semester

Also, you also can do gauge theory completely without bundles as a physicist, but anyone seeking mathematical rigor needs them

@ACuriousMind You using a book for it?

4:24 AM

I can't stand bundles. I haven't been able to find something easy introducing them, but they come up everywhere when I read and I can't make heads or tails of them.

@0celo7 My lecture notes were sufficient, so no.

Are they online??

@ACuriousMind Do you mean class notes or personal?

I meant my own, but there's also a typed version from the same course two years ago or so. They won't satisfy you, I think, and they occasionally refer to assignment solutions you (and I) don't have, but here: thphys.uni-heidelberg.de/~weigand/Skript-strings11-12/…

They're not meant to be simply read or worked through, though.

What do you mean?

Well, they're essentially a verbose version of what we did in class - and a lecture isn't designed to be consumed by a self-studier

I'm just saying I don't think I'd recommend reading them rather than a pedagogical text.

4:33 AM

@ACuriousMind For string theory I have assembled: 't Hooft's lecture notes, Nibbelink's lecture notes, Tong's lecture notes, Dine's SUSY and ST, Polchinski, BBS, GSW, Mannheim's Brane-Localized Gravity, Anderson's Cosmic Strings, the complex geometry chapter in Jost and complex geo & Calabi-Yau manifolds lecture notes by Bouchard.

I have no idea where to start. I've read a bit in BBS, Polchinski and Tong.

But since then I've gotten far wiser.

In particular, I know what CFT is :D

Well, I can't help you there. I've never learned a subject by reading a book.

I'm thinking I'll read the notes to supplement BBS, because I have that one in print. Thus I can read notes on my tablet while having the book in front of me.

@ACuriousMind what?! Never??

4:49 AM

@NeuroFuzzy Nope. I know that's kinda unusual, but I haven't read a single textbook, ever.

So what do you read then?

@StanShunpike Do you mean "What do I read for fun?", or "What do I read to learn things?"

@ACuriousMind Uh, both I guess. But more the later.

latter*

@StanShunpike Well, the basics of most topics I learn in lectures, and then I mostly just seek out whatever I find interesting on the net. I then find some paper or blog post or whatever, see different things I don't understand/know, and go search for them. Sooner or later, I'll arrive at math or physics I already know, and then I work backwards.

lisi, my hero. wanna be a surf bum physicist too. he did a Ted talk

5:02 AM

It has worked so far, and it has the advantage that I'm not bound to anyone's particular interpretation/presentation of a topic.

lisi is a controversial figure. heres a serious critique from 2010

@ACuriousMind That's interesting. I have found that works for math and physics. I learned half of my math doing just what you described via internet. In contrast, when I studied neuropsychology a few years ago, it didn't work at all. Books were the only way to find info.

@StanShunpike Yeah, most other fields seem to "guard" their knowledge much more carefully, that's true.

@vzn well, that kind shoots holes in the Scientific American article I read. Then again, if I recall correctly, Lisi may have written that article.

I dunno, I read it like 2 years ago.

think lisi has some real talent. the deep theories can take years to deconstruct/ analyze. but theres also a bit too much media hype, maybe some of it at his own "behest"...

5:10 AM

@ACuriousMind that's very interesting.

this is the somewhat now-notorious 2007 article "surfer dude stuns physicists with TOE"

from the sciencedaily article, somewhat in his defense...

> Although his paper was not peer-reviewed, and Lisi himself told the Daily Telegraph that the theory was still in development and he gave a "low" likelihood to the prediction, the idea was widely reported in the media, under attention-grabbing headlines like "Surfer dude stuns physicists with theory of everything."

which reminds me of a famous quote by einstein (lisi apparently has significantly more reserve)...

@ACuriousMind What about practice problems? My method of study for my (run-of-the-mill) quantum class right now is to scan through quantum textbooks for problems which I can't solve at first.

@NeuroFuzzy I've started to do that and it's definitely made me learn a lot faster. My uncle is a mathematician and he always says you need to do proofs to learn stuff.

> In 1919, Sir Arthur Eddington led expeditions to Brazil and to the island of Principe, aiming to observe solar eclipses and thereby test an experimental prediction of Einstein's novel theory of General Relativity. A journalist asked Einstein what he would do if Eddington's observations failed to match his theory. Einstein famously replied: "Then I would feel sorry for the good Lord. The theory is correct."

@NeuroFuzzy Well, if I weren't a student that has to deal with exercise problems anyway, I'd probably start seeking some of my own, but I don't really have the desire to solve explicit problems in addition to what I already have to do.

But I find most practice problems rather unenlightening. My ability to manipulate symbols doesn't really need training anymore.

5:21 AM

@StanShunpike Yep! More efficient use of time.

@vzn that Lisi stuff is an endless source of fun lol

@ACuriousMind that's kind of an interesting point of view.

agreed, "entertaining" stuff. its too bad lisi doesnt blog(?) dont know what the current state/ status of his theory is. the 2010 "refutation" sounds pretty definitive :|

sometimes eg with complicated math proofs, some part is "salvageable"... and the rest can be turned into "conjecture"...

@ACuriousMind haha maybe I just have easier classes/homework/more free time! 3rd year undergrad physics and most of what I'm doing doesn't feel very sophisticated.

@vzn yeah I last checked Lisi's stuff out a few days ago lol & found this physicsforums.com/threads/… it has him posting from last month

5:27 AM

interesting, smolin is a lisi fan at least in 2007. trying to remember does smolin blog?

> "Although he cultivates a bit of a surfer-guy image its clear he has put enormous effort and time into working the complexities of this structure out over several years," Prof Smolin tells The Telegraph.

@vzn the interplay between math and physics research is interesting. Obviously, with string theory, there has been a lot of math developing. But, for example, my uncle is a mathematician and basically shows no interest in physics whatsoever.

I read on Lubos blog that around 2008 Smolin and Woit 'threw him under the bus' for some reason

@StanShunpike ooh there was a video of max tegmark talking about his experiences with his father (a mathematician)

Really? that would be interesting.

I'll dig it up

5:29 AM

lol maybe they "threw him under the bus" because its wrong :p

The most damning thing about Lisi is he didn't know basic Lie theory stuff, that E_8 has an SU(5) x SU(5) subgroup, I mean that's damning, this motls.blogspot.com/2007/11/exceptionally-simple-theory-of.html cheers me up every single time I look at it lol

@NeuroFuzzy That is very possible. I've noticed that most other curricula lag at least a year behind what we can do here. 3rd year undergrad was something like (all sorts of) QFT&CFT&QCD+Algebraic Topology&Differential Geometry for me

I'm still learning Lie groups so I use it as a reference point haha

@vzn I thought that article you posted made it sound pretty definitive it's wrong.

@ACuriousMind >.<

@ACuriousMind I'm jealous! That's not a year behind, my whole undergraduate curriculum is a notch below that.

5:32 AM

@ACuriousMind That makes sense. I dunno why they don't do it earlier at other places. The GR class I took this quarter was the only undergrad one offered and seemed very subpar to me. I'm sure the graduate ones are fine but they should offer undergrad ones earlier covering the topics you mentioned.

Well, to be fair, most of these courses are formally classified as master courses, but they're about three fourths undergrads, anyway

@StanShunpike what's wrong with bundles? :)

was skimming motls damning critique. one wrinkle in all this. according to the telegraph article, Lisi has a phd. wonder, from where? what was his phd thesis? have encountered this phenomenon of phd cranks, which is seemingly quite different than the typical uneducated crank. phd cranks are a breed apart...

@StanShunpike AHA! vimeo.com/nautilusmag/videos/page:28/sort:date

We don't have this division into "undergraduate" and "graduate" versions of topics - if you do quantum mechanics, then you to quantum mechanics, and if you do relativity, then you do relativity, and so on. They don't "dumb down" topics so that "even undergraduates" can do them. If you don't want to do the heavy stuff, there's plenty of applied courses that are less math/exercise heavy, but then cover a broader range of applications.

5:37 AM

@StanShunpike Q19 is the relevant one.

@bolbteppa lolol I can't find anything that explains how they work! I get tangent bundles fine. But fiber bundles I can't make heads or tails of. Okay, let me try and see if I understand it. So as I understand, a vector bundle has a total space E that is a product between and open neighborhood and R^k and the projection π maps this product space onto some topological space. So the fiber is like the inverse map or something like that. Is that correct?

@vzn Lisi's PhD is from UCLA discovermagazine.com/2008/mar/13-e-nste-n what is so different about PhD cranks lol :)

@NeuroFuzzy I feel just like that when I talk to my uncle.

@StanShunpike I get your point, I found it confusing until I read this pdf duffell.org/chapter_4.pdf and internalized the pictures, it's the only thing that actually helped me, now I think of a cylinder as a way to remember wtf is going on :)

bolb, think of the educational system as a filtering system. phd is the top filter. and then there are phds from very elite schools, presumably even more rigorous a filter. and what pops out of the filter? a small percent of bonafied cranks. so, "wtf"?!?

idea! lets invite him into this chat! lol

5:44 AM

Is Max Tegmark the guy who is arguing against penrose and hameroff's claim that quantum gravity is acting on microtubules in neurons and facilitating computation in the brain?

@ACuriousMind ahh interesting. Well I don't want to talk more about comparisons because then I get annoyed and anxious! But that would explain why I'd lean more heavily on books! It's not so bad since university here will still put you around awesome faculty.

have studied P vs NP area for many yrs, there is a big list of crank papers maintained by a mathematician woegeorgi, and quite a few on the list have phds... seems, quite the phenomenon.... actually crank physics probably significantly outnumber the TCS "proofs"...

@bolbteppa that's a really great pdf! I finally get the mobius strip!

@StanShunpike yeah it is, if you like it and would like to post a summary of it here sometime to ensure you get it it'd really help refreshing my memory and give me an alternative perspective, no prob if not :)

@vzn haha interesting

@vzn what do you think of the "My connection of everything = connection for gravity + weak force + strong force + electromagnetism + electron + neutrino + up-quark + down-quark + other-generations" argument?

bolb re the physicsforum thread, very interesting/ current. lisi says hes still working on it. this is interesting, it sounds like someone else credible is pointing in the same direction

> Do you have an opinion about the SU(8) papers of Stephen Adler? It looks like he succeded in squezing in the SM, including the three generations, into this group. Opening a path to E(8).

Stephen L. Adler

Stephen Louis Adler (born November 30, 1939) is an American physicist specializing in elementary particles and field theory. == Biography == Adler was born in New York City. He received an A.B. degree at Harvard University in 1961, where he was a Putnam Fellow, and a Ph.D. from Princeton University in 1964. He is the son of Irving Adler and Ruth Adler and older brother of Peggy Adler. Adler was elected a Fellow of the American Academy of Arts and Sciences in 1974. He became a member of the Institute for Advanced Study in 1966, becoming a full Professor of Theoretical Physics in 1969, and was named...

5:55 AM

Great. I read about Lisi back in the day, but I was still at school then, so I had no idea what that was about, and then I forgot it. Now I'm reading up on stuff, and I have no idea what the heck all the fuzz is about. To have a consistent quantum theory you need to do more than just assign some representations and draw pretty pictures!

@vzn Lubos has offered a few reasons why $E_8$ will never work the way Lisi wants to use it, e.g.

"E8 cannot be a grand unified group because it only has real representations which is not good enough to create chiral fermions."

Also, this seems to effectively kill the idea completely by representation theory alone: arxiv.org/abs/0905.2658

@bolbteppa What's fascinating is the author's example of picking a point on the mobius band an moving along. It's reminds me of parallel transporting in that an action we think should produce a commuatitive result (ie returning to the same location here), doesn't and we end up at a different point.

That "my connection of everything" argument of his seems to destroy his whole argument, about adding one forms and scalars, I'm wondering how he could make such a silly claim, is there a way to justify it, I think he calls it a "superconnection" to pretend it makes sense

@ACuriousMind yeah there are good blog discussions by Distler, Lubos and even Lisi in the comments sections about that paper :) I think this, golem.ph.utexas.edu/category/2008/02/kostant_on_e8.html#c015146 was part of the lead up to that paper

I'm also puzzled by another thing: Where's the graviton?

6:01 AM

my main current question, has lisi published anything since ~2007? ... do not see signs so far ... not a good sign ...

Yeah here arxiv.org/find/gr-qc/1/au:+Lisi_A/0/1/0/all/0/1

@vzn The arXiv has two paper from 2010: arxiv.org/find/hep-th/1/au:+Lisi_A/0/1/0/all/0/1

haha

Damn :D

@StanShunpike yeah good point!

6:03 AM

ok, thx, 2 papers since the 2007 TOE ...

@StanShunpike This qr.ae/EbMME & this physics.stackexchange.com/a/77412/25851 are interesting on the topic off bundles also

0

Q: Flow rate of water in a gutter system

I am attempting to build a waterfall out of a gutter system. I currently have an awning that is 72" by 48" with 3" high (tentatively) buffers on each side to keep the water from flowing off. The awning is tilted 95 degrees downward from the side of a building. Connected to the awning I have a gut...

seeking additional opinions (i.e. flags, if warranted): off topic or not?

@DavidZ Seems pretty engineery to me.

Or HW, if it's really just about calculating a flow rate

Here, have a close vote.

Thanks. I wanted to make sure it wasn't suffering from a lack of appropriate attention.

Mhhh, from the conclusion of Lisi's paper: "Quantum E8 theory follows the methods of quantum field theory and loop quantum gravity - though the details await future work." He literally dodges the part where it actually becomes difficult to write down a consistent theory.

Why did anyone think this was news?

6:14 AM

@DavidZ Isn't there an Engineering SE now? It could be migrated there. Just an idea.

How did Bjorken make it into his list of thanks lol

@bolbteppa Great links! I feel like I've suddenly had a bunch of scrambled intuitions rolling around in my head satisfied in the last 15 min.

@StanShunpike yeah I know haha

7:09 AM

@StanShunpike once we establish whether it's on topic or not, then we figure out where to send it, if anywhere

1 hour later…

8:14 AM

Does anyone know of a good introduction to gauge covariant derivatives? As I understand from Danu, the gauge covariant derivative is directly related to the covariant derivative from Riemannian geometry. So I would like something that makes a connection (pun intended) between the two since I am familiar the the latter but not the former.

6 hours later…

2:12 PM

@StanShunpike I would recommend Nakahara's book Geometry, Topology & Physics if you can access it.

2:37 PM

Kyle is the kwisatz haderach! — Jiminion 1 min ago

Jimdalf the Grey

@KyleKanos I don't know what to say

Is that good?

Ever read or watch Dune?

Jimdalf the Grey

no

Okay

Basically he's saying I'm a book series' Messiah figure

Jimdalf the Grey

I suppose that's a compliment. Not much use to you outside the book series though.

Congrats anyway

2:41 PM

Well his son was better

Well, second son

The first one was killed as a baby :(

(War between relations and all that)

Jimdalf the Grey

i see

Kinda (as I understand it) like Game of Thrones: cousins are trying to kill each other to rule the planet Dune

Jimdalf the Grey

And you are their messiah

Apparently

One of the key traits is prescience

Jimdalf the Grey

Way to go, dude?

2:44 PM

I beat Jiminion to the punch on a comment (like 10 seconds in advance)

Jimdalf the Grey

Ah, now I get it

Though he was calling me that a day or two ago in chat

Not sure what started that then

Jimdalf the Grey

I have to say, that's extremely esoteric

Eh, maybe in the general populus, but amongst geeks/nerds Dune is sorta well-known

I even managed to get my wife to watch the SciFi Channel versions of the movie

Jimdalf the Grey

I protest your improper usage of the word "eh"

2:52 PM

What'll you do about it, eh?

Jimdalf the Grey

Grumble and hate you behind closed doors while still being polite to your face

That's fair enough.

Though I think that my leading "eh" is different than the typical trailing "eh" of Canadia

Jimdalf the Grey

it is

And that's why you protest it?

Jimdalf the Grey

maybe

oxforddictionaries.com/us/definition/american_english/…

2:59 PM

Lol, first recorded in English in the mid 16th century.

@KyleKanos I am editing an answer to that fellow, Agnivesh Singh, because he has difficulty in understanding that his question and the other one, are the same in essence. And Mr. Timaeus, dropped an answer to the former question and disappeared. His answer is correct, but incomplete. I asked him to complete his answer and I told him how, but probably he didn't see my comment.

@KyleKanos huh?

@JimdalftheGrey Does the top of your head leave your body when you talk? Like Canadians in South Park?

What's with all the "What are the (galactic) coordinates of X seen from Y?" lately?

@KyleKanos Were people before then not able to make vague noises? Or did they only then get the urge to write them down?

Jimdalf the Grey

@Jiminion Yes, as is tradition

3:16 PM

Maybe I should call Jimdalf the Shadout Mapes? Now that's obscure....

3:56 PM

@KyleKanos Now, what to do with the question of that Agnivesh Singh? After working on it and explaining, I wouldn't like anymore that it be deleted. And my answer is more complete than Mr. Timaeus. So, what will be?

@Sofia Closing and Deleting are two different things. Roughly speaking, only closed questions with no answers and a negative score are deleted. Even if the question is closed (which currently doesn't seem to be likely), your answer will stay.

Jimdalf the Grey

Okay, mandatory moment of reflection. Let's all just stop what we are doing and once again consider the fact that viXra.org is something that exists and that some people seriously believe it has value outside of entertainment

@JimdalftheGrey No, thanks, I want to keep my faith in humanity today :)

Philip Gibbs - inactive, England, United Kingdom

6k 13 25

general-relativity energy-conservation cosmology string-theory conservation-laws energy special-relativity

Jimdalf the Grey

@KyleKanos For being inactive, it's strange to see that he was online just 21 hours ago

@ACuriousMind sounds like denial to me

4:09 PM

@JimdalftheGrey Nope. Definitely not denial.

Jimdalf the Grey

Have you guys seen the chat argument on Jerry's post:

3

A: Is there any paper analyzing the validity of Relativity in expanding space?

General relativity was written to describe all behaviour of spacetime. And expanding universe is one small subset of the whole general class of spactimes in the phase space of general relativity. So yes, relativity does apply to an expanding universe. At least general relativity does.

apparently, Alf has had 500 downloads of his paper on viXra, therefore it must have some validity

I saw the perfect comment for that recently:

in Mos Eisley, 20 hours ago, by Michael Edenfield

@ScienceFiction&Fantasy for those times when "Unclear what you're asking" isn't good enough, I think we need an "unclear what you're smoking." close reason.

From Alf: "however, as Einstein noted, Relativity was not established in expanding space."

Wat

I honestly don't know what's going on there

Very good, faith in humanity now gone

Again.

Jimdalf the Grey

Well it was established in this space, and this space is expanding, so.... no?

@ACuriousMind Your mistake was having faith in humanity in the first place

What can I say, I'm a hopeless romantic

0

Q: a suggestion for community updates

I just answered this question that community brought up, because the question had a score of 5, and the two answers were not getting any hits and I considered they were not answering well the simple question which got these 5 votes. Now I checked and the user who asked the question came only on...

4:19 PM

@JimdalftheGrey Yeah, he was the one suggesting that energy is globally conserved in GR. You & I, I think, both got into a debate with him on that

Jimdalf the Grey

@KyleKanos Was that him? There's so many crackpots out there that it's hard to remember who said what.

I also pointed him to an article by Lubos about him!

I always wonder where the crackpots get their ideas. And how they become so convinced of them, when they either are flatly proven wrong by experiment or can't even write down a coherent mathematical statement of it.

Jimdalf the Grey

@ACuriousMind It's not hard to see where they get the ideas from. Every physicist and his dog has their own personal theories about how the universe works and what things really are. We just have the common sense to trust the accepted theories until ours can at least pass the ego test.

What I can't understand either is how they blatantly disregard the physics they know nothing about and argue with those who know it on the basis of "I understand my theories better than accepted ones, thus mine must be right and the accepted ones must be wrong"

@ACuriousMind and @KyleKanos I think it's worthy that my answer stay, because I guess that it will spare us the effort to answer additional similar questions in the future. The case of uniformly moving charges bothers people due to the idea that non-accelerated charges don't radiate. (By the way, I also thought so in the past.)

Jimdalf the Grey

4:33 PM

@Sofia why does that bother people?

@Sofia Currently there is only your close vote on it. Three people (including myself) voted to leave it open, so it's not even in the close queue anymore

@JimdalftheGrey Because the field in space changes as the particle moves on, and the changes propagate with the speed of light, but they see no reason why they should propagate with the speed of light, because the change is "not an EM wave because the charge is not accelerating" and the only thing they know to be propagating with the speed of light are EM waves.

At least, I think that's what the issue is

Jimdalf the Grey

@ACuriousMind Huh. People are weird

4:53 PM

viXra sounds bad. But academic publishing is pretty bad too. Sort of horrible, like end of science horrible. Maybe it's not so bad for Physics stuff, though.

0

Q: Funny Quantum Joke

Ok guys, this should be a fuzzy/silly question, but I have to understand why we do that (id est: the sign meaning). Let's suppose I want to describe, as a joke, the classical state of a coffee machine that is working and our of order, or something similar like a door for example. I can't see the...

quantum-mechanics wavefunction

Wasn't nearly as bad as I thought it was going to be....

Jimdalf the Grey

@KyleKanos I think I just lost my cool with a crackpot for the first time. Poor Alf

Alf?

Jimdalf the Grey

from the comment argument I linked earlier

At least I know now why Danu was reading Jerry's thesis

Jimdalf the Grey

5:05 PM

was I too harsh or unfair?

user image

@JimdalftheGrey Ugh, you are DEEPLY WRONG! (jk). I thought the expanding universe/big bang was determined by hubble, not from GR. Isn't that so?

Jimdalf the Grey

@KyleKanos I always love a good facepalm, but usually I love understanding what I did wrong to earn it even more

@Jiminion GR came first (Friedman and Lemaitre both published works on it prior to 1929)

@JimdalftheGrey I don't think it was meant for you....

5:10 PM

@JimdalftheGrey I don't think you did anything wrong., that was aimed at Alf's comments

@JimdalftheGrey why people are weird? These are beginners. We have all the time questions around this question, i.e. what kind of fields produce isolated charges in uniform movement. Is it a ridiculous issue for you?

@JimdalftheGrey You are far more polite than I would have been. (Which is why I don't enter these discussions)

Jimdalf the Grey

@Sofia Yes

@ACuriousMind That was polite? I basically told him he was wrong and a crackpot and not special in any way

@KyleKanos Excellent

@JimdalftheGrey what is a face-palm? I didn't find in the dictionary. (It smells of smth. impolite)

@JimdalftheGrey palm is usually the palm-tree.

Jimdalf the Grey

@Sofia A physical display of exasperation (and palm as in palm of your hand)

5:14 PM

@JimdalftheGrey I didn't say you were polite. I said you were far more polite than I would have been with someone pretending to be a scientist.

Jimdalf the Grey

@ACuriousMind Now I'm curious to see how you would have responded

@JimdalftheGrey no, no, the exact translation, please!

@Sofia A facepalm is the gesture of putting the inside of your hand on your face.

Jimdalf the Grey

@Sofia face and palm meet. Thus, facepalm

Exactly what Capt'n Picard is doing in the picture Kyle posted

Jimdalf the Grey

5:16 PM

A facepalm (sometimes also face-palm or face palm) is the physical gesture of placing one's hand flat across one's face or lowering one's face into one's hand or hands. The gesture is often exaggerated by giving the motion more force and making a slapping noise when the hand comes in contact with the face. The gesture is found in many cultures as a display of frustration, disappointment, embarrassment, horror, shock, surprise or sarcasm. == Origins == According to Macmillan Dictionary, the word "facepalm" first appeared around 2006, though another source has an earliest citation of 2001....

^ LOL

Best. Wiki. Picture. Ever.

@MarkMitchison just got a copy in hand, thanks for the recommendation. I will check it out.

The guy just doesn't understand the foundations of general relativity, he doesn't know the fundamental basis and is confusing examples of general relativity, namely cosmology, with the theory itself.

Facepalm is a moive?

Jimdalf the Grey

5:17 PM

I wish

"This gesture is not unique to humans. A group of mandrills at the Colchester Zoo has adopted a similar gesture to signal the desire to avoid social interaction or to be left alone." lol

That article is gold

@JimdalftheGrey and who is so exasperate here? Why? What disaster happened?

somehow my brain excluded the wiki part of ACurioudMind. All I read was Best. Picture. Ever

@Sofia: Keep in mind that @KyleKanos has a "thing" for facepalms.

lol

"double-facepalm"

5:19 PM

I don't think it's fair to insult the guy when he's making basic errors

Jimdalf the Grey

@Sofia we are all facepalming because of what Alf wrote.

@MarkMitchison That one got me too

lol

@JimdalftheGrey what he wrote, for God's sake?

Jimdalf the Grey

4

A: Is there any paper analyzing the validity of Relativity in expanding space?

General relativity was written to describe all behaviour of spacetime. And expanding universe is one small subset of the whole general class of spactimes in the phase space of general relativity. So yes, relativity does apply to an expanding universe. At least general relativity does.

read the comments

5:21 PM

@DanielSank I do enjoy a good Facepalm

@KyleKanos Indeed.

So they predicted expansion due to GR? Then why were Hubble's reveals so unexpected?

@JimdalftheGrey God save my soul!!! Read 47 comments? What I sinned?

3

We are all sinners, Sofia, but Jesus still loves you.

@Jiminion To some, they weren't.

5:24 PM

@ACuriousMind: I'm not sure Victorian time traveler is quite right, but I see where you're going there.

@Sofia: Hello. I hope your research is going well.

In fact, Lemaitre's original paper (in Belgian, published in 1927), he even showed the SNe redshifts

I still feel like I haven't wrapped my mind around expansion. I watched a TED talk on dark matter last night and my mind just is still visually too stuck in Euclidean thinking. I keep thinking of it like space just changing length scale. It would be like suddenly a mile isn't a mile but two.

That reminds me of some discussion I've had with climate change critics....esp. the dredging up of yet-another-whack-postulate when you've dispatched the current one. Like playing whack-a-mole with infinite moles.

Jimdalf the Grey

@Sofia That feeling you get after reading those comments; the pain, embarrassment, frustration, and exhaustion; that will give you a better definition of what it means to facepalm than anything I can describe

@Jiminion Yet somehow my score in that game is always a finite number

@Jiminion I don't need Jesus to love me, I need the person that looks at me from the mirror not be angry with me. And that's enough.

Jimdalf the Grey

5:29 PM

@Sofia The KGB spies on you too?

@JimdalftheGrey Then you need to whack harder!

@JimdalftheGrey do you want to tell me that you didn't understand what I said?

(Please don't take that out of context)

@Sofia I was being humorous. No worries.

Jimdalf the Grey

@Sofia No, I'm just making a dumb joke

5:32 PM

@JimdalftheGrey The supreme judge is the one who looks at us from the mirror.

@ACuriousMind The source of the jimnosperm??

@ACuriousMind you, fiend, you are the one who invented the joke that I am a Victorian time-traveler. I don't even understand what it is, but it is wicked. You tell it to me in clear words!

@Sofia Ah, the Victorian part is a reference to dmckee calling your morals Victorian when you took offense at a certain word

Jimdalf the Grey

Victorian means someone from the Victorian era. Time-traveller is obvious. He means you seem to be from that era in history

It's not an insult unless you personally don't like the Victorian era

The Victorian era of British history (and that of the British Empire) was the period of Queen Victoria's reign from 20 June 1837 until her death, on 22 January 1901. It was a long period of peace, prosperity, refined sensibilities and national self-confidence for Britain. Some scholars date the beginning of the period in terms of sensibilities and political concerns to the passage of the Reform Act 1832. The fields of social history and literature often refer to the Victorian era as Victorianism, especially when discussing the attitudes and culture of the later two-thirds of the 19th century. The...

The time traveller part is because your English always sounds a bit archaic to me - you sound as if you come from another place and time :)

5:36 PM

@ACuriousMind (don't feel offended by the word fiend, I recall it from a splendid movie, "Interview with the vampire". A very poetic and sensitive movie.)

I like fiend. Sofia, is your native language Romanian?

Jimdalf the Grey

fiend means a cruel or wicked person. It's not a name usually given out of endearment

He says he wants to modify special relativity to incorporate expanding space, I guess what he means is to take the Minkowski metric and then allow distances between points in 3-D space to grow, implying we're not in special relativity anymore, right?

Using D&D technical language, my profile picture is indeed a fiend, so well noticed ;)

Maybe we could say Sofia is steam-punk? That's kind of time travelly and Victorian.

5:39 PM

@Jiminion yes! A very good language. Very popular and full of jokes, but also, there were extraordinary poets and writers.

Jimdalf the Grey

@bolbteppa essentially yes. He wants to make GR without it being GR

@ACuriousMind what is D&D?

Dungeons & Dragons

Dungeons & Dragons (abbreviated as D&D or DnD) is a fantasy tabletop role-playing game (RPG) originally designed by Gary Gygax and Dave Arneson, and first published in 1974 by Tactical Studies Rules, Inc. (TSR). The game has been published by Wizards of the Coast (now a subsidiary of Hasbro) since 1997. It was derived from miniature wargames with a variation of the Chainmail game serving as the initial rule system. D&D 's publication is widely regarded as the beginning of modern role-playing games and the role-playing game industry. D&D departs from traditional wargaming and assigns each player...

Dungeons and Dragons. A game. Some monsters were described in the "Fiend Folio".

Jimdalf the Grey

@ACuriousMind Beat me by 3 seconds

5:40 PM

(callback)

He's fiendishly fast.

(sp)

Jimdalf the Grey

@Jiminion You know you can edit messages, right?

@Jiminion I took Improved Initiative on my last level-up, so yeah, I'm fast as hell

@Jiminion you wanted to say, he is fiendishly fast.

@Jiminion but fine&dishy I don't think is bad.

@JimdalftheGrey Yes, but it is an insult to commenting as a performance art.

@Jiminion (dishy - I mean pleasant face).

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