The h Bar

John Rennie

20:00

Ohanian's book is actually quite affectionate. Although it's titled Einstein's Mistakes he makes it very clear in the introduction that it isn't an attack on Einstein.

Danu

@JohnRennie Well, most reviewers disagree with you.

Ben describes an example in detail of Ohanian mischaracterizing the situation.

John Rennie

It had never occurred to me to read the Amazon reviews, but I'll have a look.

Danu

@JohnRennie I don't really have any other option, sadly, since I don't own Ohanian's book.

In any case, I think it's clear that it is more accurate to characterize Einstein as an "excellent student" than as a "bad student who just got by".

John Rennie

I'm guessing you are especially interested in reading it. If you are, some might say I have a pdf of it, though I couldn't possibly comment.

0celo7

@JohnRennie You're a regular Ed Thatch.

Physics Meta

20:06

0

Q: questions regarding the proof of a physical identity

Is it really on topic to ask questions regarding an exact proof/how to approach the proof of a particular identity, or a physical equation ?

John Duffield

@dmckee : I want to lodge a complaint. I've just posted an answer, and received an immediate downvote from some malicious chatroom troll even before they had time to read it. It isn't the first time that's happened.

Slereah

By the way I still don't know the proof of Hadamard forms

dmckee

@Danu As AcuriousMind notes, I sometimes vent about things happening on the main site in chat without naming names. I suppose that you can generally find out what I'm talking about if you care to work your way through my recent activity.

Slereah

I should look it up someday

It's in an old ass book I recall

dmckee

Of course, I try to not vent any of that frustration in my comments, so you really would have to read all the questions I've been active on recently.

Slereah

20:09

It's like SOLVING GREEN FUNCTIONS ON A RIEMANNIAN MANIFOLD

dmckee

@JohnDuffield Why tell me? There is literally nothing I can do about.

DeNiSkA

all physics geniuses chat.stackexchange.com/transcript/message/28270644#28270644

John Duffield

@dmckee : because PSE is going downhill, and there's some good posters out there who are ex-posters, IMHO because of dishonest voting. And you're a moderator.

John Rennie

@0celo7 Arr, Jim Lad.

Slereah

@DeNiSkA Collision with solids is a bit more complicated

1) the entire wall does not have to move 2) since the wall is much heavier, it does not have to move with the same acceleration at all

dmckee

20:14

@JohnDuffield Do you really want me and the other mods to start deciding that certain users are trouble makers and get busy wielding moderator powers on that basis? Luckliy for you that's something that we are not suppose to do.

Danu

@dmckee I tried, but failed.

DeNiSkA

@Slereah but to conserve momentum earth should move (resnick-halliday from fundamentals of physics)

Slereah

Well yes, but

Try computing the acceleration upon earth

Danu

@JohnDuffield Didn't you say this... 6 months ago?

Slereah

The mass of the earth is... $\approx 10^{26} kg$

Danu

20:15

Did anyone leave since then?

Slereah

Also why didn't Duffield leave

He is the best poster

Surely he should be the first to leave

John Rennie

@Slereah: you're a duck?

Bernard Meurer

cranks vs quacks: Olympics anyone?

DeNiSkA

@Slereah yes! i agree it will move with velocity almost zero.(do you agree?)

Slereah

Quack :V

Danu

20:17

@JohnDuffield Maybe some food for thought: 1) Have you ever left a "discussion" here while not proclaiming yourself to be "the winner"? 2) Has any discussion with you in this room ever resulted in anyone saying you're right?

Slereah

@DeNiSkA Pretty much

Danu

(Please don't answer, I don't wish to debate, just perhaps to spark some thoughts)

Quanks---sounds nice

Slereah

Bernard Meurer

@Slereah Change your avatar :p

Slereah

Nah I like my Leonard J. Crabs

0celo7

20:21

@Danu 1. Someone who is never wrong will always win. 2. I concede that Duffield is correct.

Danu

@0celo7 I didn't ask you anything

0celo7

@dmckee rekt

@Danu Oh really

DeNiSkA

@Slereah now my question comes!
to conserve momentum ball has imparted very negligible velocity to earth so when it does some infinite rebound collisions (like hitting walls to & fro ) all velocity of the ball will drain and finally the ball's velocity will approach zero. (*is my understanding correct*?)

Slereah

What

dmckee

@DeNiSkA No.

ACuriousMind

20:22

You're doing exactly what you asked others not to do, @Danu :P

John Rennie

@0celo7 "rekt" = "correct", or "wrecked"?

Danu

@ACuriousMind No; I only asked others not to engage in "physics discussions", which I'm not doing.

0celo7

@JohnRennie lol so old

The second one.

DeNiSkA

@dmckee but why ? (::*politely*::)

dmckee

Because after the first impact the opposite wall will me moving ever so little toward the ball.

Danu

20:23

In particular, I took great care not to say that one should not talk to him at all, which didn't stop him from accusing me of doing so nonetheless.

0celo7

@ACuriousMind What should I have for dinner?

Slereah

dmckee

Assuming we're talking about fully elastic interactions, of course.

John Rennie

@0celo7 It was a serious question, I'm too old to understand your banter.

Slereah

I am not quite sure where Something Awful got the face for Leonard J. Crabs

Bernard Meurer

20:24

@dmckee I want the mods to be absolutely authoritarian. Make Physics SE the new stalinist era!

Slereah

0celo7

@JohnRennie I know it was serious, but you're still old :)

ACuriousMind

@Danu I see. Lawyering your own rule, I like it ;P

0celo7

And I gave you the correct answer.

Danu

@ACuriousMind Of course, you're quite right that the best way to avoid bad chatroom vibes is to not talk at all.

dmckee

20:24

@BernardMeurer Too bad. I don't like myself when I starting doing that stuff.

Danu

@ACuriousMind I actually didn't make that up on the spot, believe it or not. I'm forced to be careful here...

Bernard Meurer

@dmckee :)

dmckee

@JohnRennie I believe he means that mine remark was a stinging rebuke. Or something like that.

DeNiSkA

@dmckee so you mean ball on the second collision, will get the velocity back?

ACuriousMind

I guess using "rekt" for that is one of these "finesses of entertainment" I keep hearing about

dmckee

20:26

@DeNiSkA Yeah. If the collisions are elastic then the energy must stay in the bulk kinetic channel. That's what "elastic" means.

John Rennie

The youth of today. I don't know what the world is coming to.

0celo7

@dmckee yup

Bernard Meurer

rekt, verb: to rek
definition: To cause one/one's argument to look like a goof

0celo7

@JohnRennie Greatness, my old friend.

Greatness.

Danu

#GreatAgain

0celo7

20:27

@ACuriousMind no

dmckee

@JohnRennie Waste and ruination. Same as always.

John Rennie

@0celo7 That's OK, I'll be dead by then. Enjoy your, erm, greatness.

Slereah

Hey @0celo7

Did you know

0celo7

The youth are to the world as DJ Trump is to America. The interpretation of that statement can be wide and varied.

Slereah

It's basically impossible to have a spherically symmetric static wormhole

0celo7

20:28

@JohnRennie you're like 55

@Slereah uh isn't that Schwarzschild

Do I need to get Visser's book?

John Rennie

And you were planning to achieve "greatness" within the next 50 years?

Slereah

It's actually not in Visser

John Rennie

Oh well, it's good to have ambitions I suppose

Slereah

It's some paper

I forget which

I think it's called like

No go theorems for spherically symmetric spacetimes

Or some shit

0celo7

WORMHOLES OR SOME SHIT

Slereah

20:29

the very same

Basically if you try to find a solution for a spherically symmetric spacetime with reasonable sources

0celo7

@JohnRennie WW3 is coming.

Slereah

You find that $\frac{dr}{dl} > 0$

0celo7

So?

Slereah

For a spatial section like $f(x) dl^2 + r(x) d\Omega^2$

John Rennie

@0celo7 Will that be here before or after global warming drowns all our coastal cities?

Slereah

20:31

But

For such a spacetime to be a wormhole

0celo7

@JohnRennie implying that's realistic at all

Slereah

The function $r$ has to have a minimum

The throat size of the wormhole

Also it's $\frac{d^2r}{dl^2} > 0$ I think

Hence no minimum

John Rennie

Oh no, I've opened the global warming bag of worms. Time to go!

Slereah

Unless you allow for specific fields

0celo7

On phone, I have no clue what you're talking about Sam

Slereah

20:32

Like phantom fields or non-minimally coupled scalar fields

John Rennie

Time for bed, I have to be at work in 8 hours. See you all tomorrow.

Slereah

IIRC it's impossible for like

Any number of interacting scalar fields and vector fields

0celo7

How good of a read is Visser? Can you send me Hawking and Gibbons? Are you still reading that

Slereah

Not sure about spinor fields

I don't give books away fool :V

0celo7

@JohnRennie whimp

ACuriousMind

20:34

I'm not sure anyone is listening to your rambling, @Slereah ;)

0celo7

I am, Bajoran

Slereah

You should, it is interesting!

0celo7

Btw that's a word in my phone's dictionary now

John Rennie

@0celo7 comes with age

0celo7

I've said it enough times

DeNiSkA

20:35

has here anyone written IPhO?

Slereah

What is ipho

Also that article also had some weird thing I've never heard enough before

Spacetime horns and spacetime flux tubes

A bit odd

Never read those terms anywhere else

DeNiSkA

google.co.in/…

what happened?

Danu

I just had a nerve-wrecking draw after coming back from a piece down due to a blunder by the opponent.

user54412

@Danu Uhh, no? It's a reason for downvoting, but I always vote to leave open if the only reason is insufficient effort.

Danu

20:52

@ChrisWhite That was just a statement of fact

There are many questions closed for the exact reason that they "show insufficient effort"

DeNiSkA

why everyone has put john duffield on ignore?

user54412

^^ okay, I don't dispute that fact

Danu

@DeNiSkA Just ignore the matter---it's a complicated story with no really interesting features.

Now, if you disagree with that reason for VTC-ing, then maybe you can bring it up on meta.

DeNiSkA

@Danu i see!

0celo7

@DeNiSkA It is interesting but Danu is a grumpy

ACuriousMind

20:54

@Danu It's already there, with no real consensus, but actually back then a majority seemed to say "don't close these questions".

user54412

@Danu Perhaps. More pressing though I'm formulating a request to have downvotes have more effect on this site.

Danu

@ChrisWhite LOL, good luck.

DeNiSkA

@0celo7 they say the crushed version of it!

Danu

I am 100% behind you on that, but it ain't gonna happen.

user54412

Yeah. I'm not expecting to win.

user54412

20:57

@JohnRennie Nooo but he's the worst crackpot. He wastes taxpayer money trying to prove logical inconsistencies based on a middle school understanding of physics.

dmckee

@ChrisWhite I assume you are aware of the once pending version of that from the Trilogy days that resulted in question upvotes having less weight instead?

user54412

@dmckee Yeah. But I also think costs and effects of votes do vary in some rare site-by-site cases.

user54412

I don't want to change how SO does things, but just how we do things.

dmckee

Fair enough. I just figure you have to make the case in the context of that older discussion.

user54412

Unlike code sites, we get answers that are patently wrong yet aren't downvoted quite into oblivion. Or rather they are, but not into 5*oblivion, which is what's needed to keep people from gaining rep.

3

Danu

21:02

4

Q: What is a spinor?

In a youtube video, sir Michael Atiyah mentioned that even after working during the most of his life on spinors, he doesn't know what a spinor is. Now surely that was part of his humorous introduction to the talk there, but still, we work on spinors but how much are we capable of setting its defi...

spinors

dmckee

@ChrisWhite Yep. ::starts whistling 'I've got a little list...' from _The Mikado_::

Bernard Meurer

Why did they take away our hats?

user54412

@JohnRennie They are utterly mad though. Sticking two plates close to each other does not make negative energy density as far as GR is concerned.

Danu

@ChrisWhite Yeah...

dmckee

@BernardMeurer So that you'll appreciate them more when they come back next year?

Bernard Meurer

21:05

@dmckee I had some pretty sick hats that made my whole family proud

ACuriousMind

@Danu I still don't understand how that didn't get closed as too broad or shows no research effort.

Danu

@ACuriousMind I don't know. You can vote for that now.

ACuriousMind

@Danu No, I can't

Danu

Also I was thinking if it'd be nice to have a mathematical answer to it

@ACuriousMind Tomorrow, then.

I pushed it into the queue

0celo7

> A spinor is a mathematical representation of a harmonic standing-wave quantum field "topological structure" or excitation which typically exhibits a spin ½ geometry which in turn can be likened to Dirac's belt or the Möbius strip

Danu

21:15

Word salad!

user54412

Scheduling my thesis defense is apparently half the battle.

2

user54412

I can't imagine how people do it with external examiners

0celo7

@ChrisWhite Donuts.

Is your thesis done?

user54412

@0celo7 troll

user54412

If my thesis was done, I'd be off doing... fun. Or whatever it is that normal people do.

0celo7

21:20

Which part?

user54412

donuts isn't trolling

user54412

they're also not sufficient to get tenured professors to change their schedules, unfortunately

0celo7

Have you tried getting good looking females in the room?

bolbteppa

@ACuriousMind Your perspective on that spinor question is shocking tbh

user54412

@0celo7 Implying I'm not?

Slereah

21:25

Quite a good looking lady you are

0celo7

@Slereah Who is that?

0celo7

21:51

Slereah

That is @ChrisWhite

0celo7

@ChrisWhite Tell Princeton to get its shit together

I get a different photo for you on my phone :V

Unless that's you in both pictures

@ChrisWhite Why isn't LaTeX on your CV as a skill?

user54412

22:15

Latex is like the quadratic formula -- no need to tell people I know it :p

0celo7

@ChrisWhite You're saying that to a guy who does not know the quadratic formula.

0celo7

23:07

@dmckee How do you feel about Basil Hayden's?

Physics Meta

23:56

0

Q: Where to ask questions that are "on the boundary between science and philosophy"?

The question that I have in mind, which may very well have a definitive answer that I am not aware of, or include false premises, is this: Since particles are "probability clouds" and it is possible to have identical particles (fundamental particles), is it possible, or at all meaningful, to ide...

discussion scope questions

DeNiSkA

who is this physics meta?

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