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vzn
1:15 AM
@PM2Ring btw real explosions involve cooling also. which reminds me, a sharp cohort cited Neumaier a long time ago but havent seen him cited in ages. think very worthwhile to look at for anyone who puzzles over interpretations/ foundations/ bohmian/ fluid mechanics etc Foundations of quantum physics II. The thermal interpretation / Neumaier arxiv.org/abs/1902.10779
 
 
3 hours later…
4:45 AM
Any good reference of Physics lab manual in which stuffs like verniers are discussed extensively?
From extensive I mean, the author first introduce about the fundamental principle then tells how this is applied in verniers.
 
 
1 hour later…
6:16 AM
@ZeroTheHero it can be done, but you have to work at it! I can think of only one person who has managed it, and he has managed to get himself suspended on pretty much every site he's joined so he's a professional! :-)
 
6:54 AM
@JohnRennie space.com/black-hole-wobbling-jets-warp-spacetime.html It's nice that we've observed this effect, I think it might be the first time we have, at least to this extent!
 
@kylecampbell what is red pink colour in first image. Isn't space all black
 
@kylecampbell I thought that was really cool :-)
 
Which picture in particular do you mean?
 
We tried to observe the Lense-Thirring effect around the Earth but the results were inconclusive. This is a direct and really nice observation of it.
 
6:59 AM
Oh, that's an artist's rendition. I suppose he's trying to depict the accretion disc.
 
@Scáthach I think that's just supposed to represent temperature. The accretion disk gets hotter towards the centre.
 
Ohkay
 
I wouldn't take it too seriously.
 
It is very cool, and I had no idea about that effect before you mentioned it! Also very cool.
 
As Kyle says, it's just an artist's representation.
@kylecampbell it was Gravity Probe B attempted the measurements.
13 messages moved from Problem Solving Strategies
 
7:42 AM
Can someone provide sources from where I can read more about fierz-pauli equation or quantum field theory approach to gravity in general? I tried searching on Google but I could not find a good review. Maybe someone can help here?
I don't know what kind of conversation takes place in this chat room, so I apologize in advance if my query is out of the topics discussed here.
 
@ManvendraSomvanshi it's a perfectly good thing to discuss here. However I don't think any of the chat regulars work in quantum gravity so we probably can't help much. Sorry :-(
 
8:07 AM
How can I make a small zapper on my skin without using a transformer and using a 9V battery?
 
Is it appropriate to ask a question on avengers:endgame (related to physics)? Because I have found several mistakes in the physics of the movie and I am not sure if I can discuss it since it will spoil the movie for anyone who did not watch. Any suggestions?
 
@ManvendraSomvanshi I was thinking about the exact same thing!
The movie was awesome!
 
@NovaliumCompany my opinion is quit contrary. The movie could have been made better
 
8:38 AM
@ManvendraSomvanshi I would be cautious about any spoilers. Maybe create a separate chat room for that discussion, or wait a bit longer. Is it really worth discussing the science of a Marvel film? Do we expect it to be rigorous? :-)
 
9:10 AM
@JohnRennie That BH antimatter question just spawned one about antimatter & naked singularities: physics.stackexchange.com/questions/477326/… I can't find a dupe target that covers naked singularities (pun intended).
@NovaliumCompany Use a voltage multiplier, like I said yesterday. But if coils are allowed, when I was a kid I made a zapper from an electromechanical buzzer & a small audio transformer, wired backwards. That is, the buzzer was wired into the transformer secondary, using the primary as output. It could make visible sparks several mm long, just from a 1.5v cell.
 
9:31 AM
@PM2Ring I have no idea what happens when you throw antimatter into a naked singularity. I'm not even sure if it makes physical sense since as I recall naked singularities give you problems with causality.
 
9:42 AM
@JohnRennie Me neither. I know that with a normal classical BH the singularity isn't in the past lightcone of any observer, but I don't know how it works with a naked singularity.
 
@PM2Ring I'll just use the igniter from a lighter? Or it doesn't work?
 
@PM2Ring I think the naked singularity gives us the same problems as a Norton's dome i.e. outward trajectories just start without it being possible to determine any initial conditions. In this case it's because those initial conditions would be at the singularity and that isn't part of our manifold.
 
@JohnRennie That makes sense. I guess. ;)
@NovaliumCompany Sure, you can get a zap from an igniter. But the ones I've seen are piezoelectric: they work by mechanical distortion of a crystal, they aren't powered by a battery.
 
 
3 hours later…
12:35 PM
@JohnRennie fun fact, the history/physics prof I’ve been working with was a student of John Norten
Also, there’s a philosophy conference in our area coming up later in the month that Norten will be speaking at
Norton*
 
12:52 PM
Now I come across a new term, secret symmetry. I wonder if it just refers to the symmetries associated quantum groups. I have seen the term hidden symmetries are used to refer to symmetries of this kind previously.
 
@CaptainBohemian context?
 
 
2 hours later…
2:57 PM
What kind of laser will I need to make a Michelson interferometer at home?
 
user351417
I think that New Alexandria's election nomination is actively harmful: if it hadn't been set up, the nomination phase would have been extended, so more people would have seen Kyle's removal and hopefully nominated themselves. But now, we have ended up with only two candidates but the system thinks we have three and things are proceeding as normal.
 
3:17 PM
@Rishi Why are you suggesting the nomination phase would have been extended?
@Rishi Yes it is regrettable that so few people stepped forward to the election, but there's nothing harmful in anyone putting their names forward: you're free NOT to vote for her.
 
An example of online elections gone bad (from an old MUD experience of mine)
Person A is the org head. Person B disagrees strongly with a recent action of theirs, and contests them for leadership. Person C throws their hat in the mix, and Person B---caring more about getting A out---tells everyone to vote for C instead.
Person A goes on to win by one vote over Person C...with Person B receiving one vote.
(The total number of votes was something like 30. Not a huge number)
Boy was that fun :/
 
user351417
3:35 PM
@ZeroTheHero I'm quite sure that the procedure is that if the number of nominees is equal to the number of positions, the nomination period is extended by a week (example).
 
user351417
That's why I decided that it's harmful: until now, I was under the impression that it'd be just fine if we don't elect someone with no past participation. But now it looks like the existence of that candidate has had a negative effect: it acts like a 'dummy' nomination.
 
3:49 PM
@Rishi there's a lot to be said about what could have been better overall, but we have 2 good candidates & a third who indicated in comments that they'd at least care about the site if elected (which may suggest something good about them compared to the other qualified people who didn't nominate themselves)
2
I don't think anything is broken or harmful here
 
4:08 PM
@Rishi It's might be just because it's a pro tempore election on a beta site, but in the last engineering election, they had two nominations and appointed them directly engineering.stackexchange.com/election/1
 
I'm reading a book on How to talk to anyone about proper ways to make good relationships and this book talk s about how you should smile... and to make people like you, but as far as I know Steve Jobs wasn't particulary nice and yet he succeeded, how and why?
 
@NovaliumCompany Steve Jobs was building a large company for profit, not actively working at making good relationships
 
Yes but you need good relationships in order to build such a big company?
 
@NovaliumCompany some people are charismatic and make other people admire them. But I'm not sure that admired is the same as being liked.
Many people admired Steve Jobs, but how many people liked him is another question.
 
The book is called How To Talk To People, check it out and tell me if it's worth reading if you want to make it in business where you'll meet and talk to a lot of people.
 
4:20 PM
Are there mathematical physicists who get a better rep than string theorists
 
@JohnRennie And just because people admired Steve Jobs, that doesn't mean that trying to emulate him is necessarily a good idea
 
And where do I sign up
 
@NovaliumCompany You need good business relationships. That can be accomplished in other ways besides just having good interpersonal skills. It can also help, but generally the "big innovator" types suffer a bit more on social skills, but make up for it in other ways so that it is often perceived as just "eccentric"
 
@Semiclassical I guess it's a good idea if you want to be a multi billionaire.
 
depends on how long you want to be a multi-billionaire
 
4:22 PM
I'd quite like to try. Just for a short time :-)
 
I have in mind all the stuff that came out about Elizabeth Holmes / Theranos
she was pretty well obsessed with trying to emulate Steve Jobs
 
@Semiclassical yes, that all went rather spectacularly wrong, but I bet she still has enough money hidden away that she won't be going hungry in her old age :-)
 
So how people with poor social skills manage to build such big empires which are based on relationships?
 
yeah, you have to wonder about that
 
I wouldn't mind emulating Steve Jobs for awhile, but if I got cancer, I think I might take a different approach...
 
4:24 PM
@NovaliumCompany humans are weird like that
 
@JMac yeah, that too
 
@JohnRennie ??
 
@JMac I don't think being a multi-billionaire gives you cancer
 
@NovaliumCompany Bringing something to the relationship that others aren't. You don't always have to have something social to offer, but you need to have something.
 
@NovaliumCompany humans are just weird sometimes. How else do you explain Stockholm Syndrome?
 
4:26 PM
So reaa
Ops
 
@JohnRennie No, but if being Steve Jobs means you try to respond to a treatable form of pancreatic cancer by "alternative medicine"
 
@JohnRennie No, but he was diagnosed with treatable cancer and went through alternative medicines instead of proper treatment, and the general consensus is that he could have easily survived
 
Shrug :-)
 
4:27 PM
Also worth noting that they speculate the pancreatic cancer was potentially triggered by an all fruit diet that wreaked havoc on his pancreas trying to deal with all the sugar
 
Maybe he didn't place as much emphasis on long term survival as the rest of us.
 
I think he just had strange alternative beliefs and didn't trust medical science enough
 
@JMac humans tend to have strange alternative beliefs. Take organised religion for example.
 
>According to Jobs's biographer, Walter Isaacson, "for nine months he refused to undergo surgery for his pancreatic cancer – a decision he later regretted as his health declined".[114] "Instead, he tried a vegan diet, acupuncture, herbal remedies, and other treatments he found online, and even consulted a psychic. He was also influenced by a doctor who ran a clinic that advised juice fasts, bowel cleansings and other unproven approaches, before finally having surgery in July 2004."
 
@JohnRennie No doubt. I still wouldn't want to emulate those beliefs though :P
 
4:31 PM
I have less respect for alternative medicine than organized religion, frankly.
(though I guess that depends on context. people don't start wars over alternative medicine)
 
So reading the book on how to be more socially adequate isn't necessary for build a company based on relationships with other smart people?
 
I doubt there's any strictly "necessary" book for becoming successful
 
@Semiclassical not, but they may well end up starting a pandemic or something
 
@Mithrandir24601 true dat
 
But really, the most successful entrepreneurs lack social skills but still build those huge companies, how!?
 
4:33 PM
[citation needed]
Just because there's a number of high-profile examples of such people, doesn't mean they're "the most successful entrepreneurs"
 
@Semiclassical Yeah, I agree completely. Religious crusades and stuff, that's obviously too far; but organizing into groups to work towards common goals actually can lead to some good progress. In the modern world it's basically redundant. Actively going against proven science is usually not a great call (though I can kinda emphasize with the mistrust, I don't agree with it at all)
 
@JMac i have a certain respect for organized religion, in the same way as I have respect for culture and narrative in general
 
This isn't the best place to ask these questions if I have to be honest.
 
I think there is an interesting question there, mind: How is it that the Silicon Valley model / start-up culture has been as successful as it has?
(with the case of Theranos being an example of how that can go badly wrong)
 
Greed and cupidity.
 
4:37 PM
yeah, there's a fair bit of that
 
More precisely greed, cupidity and venture capitalism :-)
 
Is it possible that both parties of the relationships building a company are socially incapacitated and that's what creates that strong bond and unification between them?
 
there's a reason why
is such a classic meme
 
@Semiclassical people like shiny things & SV promises lots of shiny things
 
4:43 PM
Is it possible that both parties of the relationships building a company are socially incapacitated and that's what creates that strong bond and unification between them?
 
@KyleKanos yep
 
I also suspect there's a limit to how much lenders & investors understand technology & technical terms, so just dumping money into "promising" entities is the norm
 
yuuuup. "shut up and take my money" can apply to the VCs as well
part of why Theranos is interesting, though, is that while it acted how a tech company might
it was a healthcare company
 
@NovaliumCompany successful businessmen, like Steve Jobs, tend to be very highly motivated, very confident and very focused - even monomaniac. For some reason other humans find this sot of behaviour inspiring even if they don't like that person.
 
It's probably also worth noting that "socially maladapted" is by definition a matter of context
 
4:48 PM
Jobs for example ran Apple on the basis that he was always right. And usually he was, though not always.
 
So I've come to the conclusion that social skills are not necessary for success?
 
Depends on what you mean by social skills. You need the right skills to be successful, but those skills are not the same ones that will make people like you.
Being rich but not liked has its upsides. You can always pay people to lie convincingly that they like you ...
 
Yes, you likely will need to be able to talk to people, that requires social skills. Do they need to be on par with business acumen? Maybe not, but they can't be neglected entirely
Jobs may not have been a personable guy, but he sure could deliver a speech & get people motivated to buy the next big thing from Apple
 
I'm usually not the social guy in the group and I don't talk a lot but that doesn't mean that I should change in order to succeed?
 
I generally consider public speaking a social skill, if you haven't noticed
@NovaliumCompany largely depends on your definition of "success"
 
4:53 PM
@KyleKanos building a successful company
 
Again, successful how? Making money? Or making a useful contribution to society (without monetary impacts)?
 
The second one
 
Whether or not you "need to change" isn't something strangers on the internet could or should tell you (probably similarly for books) That's on you & your experience.
 
Has this really not been asked before? I cannot find a duplicate ...
 
As well as your desires and focus.
You could do the tried & true method of "If at first you don't succeed, try, try again"....
 
5:00 PM
Well, I will just be myself, although I am changing one thing, I will become better at overcoming fears and seeking discomfort.
 
Replace the fear with a different one. If you are afraid of failing, become more afraid of regretting not doing whatever in the first place
 
@KyleKanos Right on!
 
5:18 PM
@JohnRennie Maybe it hasn't been asked because the Wiki article on stellar collisions says in its very first sentence that the loss of orbital energy is due to mass loss or gravitational radiation :P
 
5:58 PM
Speaking of gravitational radiation, is this comment basically correct, as far as it goes?
When black holes collide, the energy released as gravitational waves comes from their mutual gravitational potential energy. Crudely speaking, the BHs don't lose any of their internal mass. However, when considering a region that contains 2 BHs saying exactly where the mass lives isn't straight-forward. ;) — PM 2Ring 9 hours ago
 
6:13 PM
@JohnRennie It's now got a giant answer by JEB, which is mostly a quote from the Hulse-Taylor Nobel prize press release. Should that stuff be in a quote block?
 
6:28 PM
@PM2Ring done. Also, I'm of the opinion that it should be a community wiki since there isn't much beyond the quote
 
6:42 PM
@KyleKanos Thanks. I kind of agree re community wiki, to stop the author getting much rep from it. OTOH, I know that on SO community wiki is considered to be a deprecated feature, a leftover from the early days, before anyone could edit anything. A CW answer is unlikely to be maintained by the author, or anyone else, and that can be a worse outcome than the author picking up a few points that they probably don't really deserve. Of course, the Physics CW policy may be quite different to SO's.
Another downside of CW answers that's probably even more relevant on Physics than on SO is that it allows the author to post controversial material that's likely to attract downvotes, without the author worrying about losing rep.
 
'I just watched a 3 minute video on chalk and wasn’t disappointed'
 
7:01 PM
So, I noticed
I came across this in a material provided by my faculty in a coaching institite — ImmortalUchiha 2 hours ago
 
I was watching a lecture on Dirac's life. The lecturer said that Dirac had rejected quantum field theory, predicted by his own equation. Why did he do so? He was Dirac, there must have been some strong reason for him to reject QFT.
 
... in passing, and got to wondering what a "coaching institute" is. The obvious explanation is that it is a private tutoring service gussied up in a fancy name. Anyone know if that is the case or there is a better explanation?
@ManvendraSomvanshi Naively plowing ahead with QFT generates all kinds of mathematical headaches which require a lot of infrastructure to resolve (when they can be resolved at all). Search term "renomalization".
Easy to get dispirited about that. Especially early on.
 
@dmckee In India there are these messed up coaching institutes that 'prepare' students for an entrance exam called JEE (entrance in an engineering college). These institutes are very famous (at least in India).
They just throw information at students that is to be replicated in the exam.
The exam is actually very hard. And due to high competition many students join these institutes.
@dmckee Isn't the Dirac sea considered to be the first field theory. Or at least kind of a proto-field theory?
@dmckee yes that is correct. But these are not ordinary tutoring services. These institutes earn in millions. Just wiki FIITJEE.
These organisations are a very big issue in India which no one seems to address.
be addressing*
 
7:26 PM
@ManvendraSomvanshi Feynman was able to change that attitude in Brazil 6 decades ago. See v.cx/2010/04/feynman-brazil-education But I fear that the problem in India is just too big and has too much momentum for the system to be changed without some kind of miracle.
If you want to read more of my ramblings on this topic see chat.stackexchange.com/transcript/71?m=49872953#49872953 and the following posts.
 
@jmac Apropos of our conversation earlier: rollingstone.com/culture/culture-news/…
 
so is the temperature of a black hole horizon uniform? I guess it's impossible due to relativity. does this mean that temperature is not well defined for a black hole? Therefore its mass?
 
@PM2Ring I don't think there'd be any change in the education system in India unless there's a strong protest or maybe, a revolution kind of thing.
 
7:53 PM
@Semiclassical Sounds about right for a scientology cruise.
 
@Rishi We now have 5 candidates. That should make it interesting.
 
8:15 PM
I'm curious. What would happen if there were only 2 nominations for filling up two vacant mod positions, when the nomination deadline ended? Would those two people become mods directly without any voting?
 
For an undergrad interested in theory, would it be more beneficial to take differential geometry than topology? Also, what are the math courses that are probably most beneficial to prioritize for physics?
 
@thermomagneticcondensedboson You can assign a Hawking radiation temperature to a BH, but it's kind of meaningless, since the BH is sitting in a bath of thermal radiation (the CMB) that's at least a billion times hotter. Also consider the HUP as applied to the position of the event horizon. But of course we need a quantum gravity theory to talk honestly about this stuff. Even Hawking radiation may be fictitious, since it was derived using a semi-classical model that some people consider rather dubious.
 
@SDFG i believe that is the case
@kylecampbell forget math, take programming :) :P
 
@kylecampbell You'll need both, although differential geometry probably a bit sooner than topology. (Lie) group & representation theory don't hurt, either. Most math appears somewhere in physics, and "theory" is really broad. A condensed matter theorist will do very different things from a general relativist.
 
8:31 PM
@KyleKanos Isn't that a possible loophole? I mean, just in case there's one less nomination than the no. of vacant positions, and a rather unqualified user spots this and makes the nomination right before the nomination deadline ends (so that his nomination can't be cancelled) ? Isn't there some way to prevent this from happening?
 
I suggest taking the math that seems interesting to you, rather than slogging through it out of some imagined necessity for physics. Most physicsts manage perfectly well without much in the way of formal math :P
@SDFG The way to prevent this is for enough people from the community to nominate :P
Honestly, if really no one except a completely unqualified user nominates, you should be worried about the state of the site, not about the soundness of the election system.
 
@ACuriousMind True that. But this would only lead to a further downward spiral. And the situation isn't limited to no nominations. I mean, even if there's just one nomination less, that's a chance for a biased user to get the diamond. You're telling me there's really no way to prevent this? :O
 
@SDFG not sure I call it loophole, but yes that is possible
 
@SDFG Users that abuse the diamond won't keep it for very long.
Don't think that SE just appoints the candidates and then never looks at the site again.
 
@ACuriousMind Hmm. That's a sort of cure. Gives me hope.
Furthermore, from what I can gather, the elections aren't really that frequent, are they?
So that reduces the chances even more.
 
8:39 PM
There's been 2 that I participated in & I've been here like 5 years
 
Oh.
 
They happen whenever SE and/or the mod team of the site feel think it would be a good idea. It depends on the site, but I'd guess for most sites it's less than 1 every 2 years
 
rob
That election FAQ is much harder to find than it should be.
 
@rob Oh wow. This is good. The thought of biased mods around here was a bit scary.
 
vzn
lol!
 
8:58 PM
Thanks for the advice @ACuriousMind. I think you're right about taking what you're interested in! Since I'm interested in both of them, I guess I was wondering what be more useful in physics. I think the topology course where I am is quite theoretical though, i.e., group theory is a pre-req whereas differential geometry would be more immediately applicable to something like GR. Although, most of the GR I've been exposed with just uses tensor analysis that can be learned with the physics.
Also, lie theory is a grad course that requires group theory (with finite groups) as a pre-req, which I just can't fit in.
I also don't immediately see the usefulness of group theory in physics if we're not talking about continuous symmetries... Although it's cool on it's own sometimes.
 
@299792458 I would add also Valter Moretti to the list.
 
@PM2Ring Thanks for the information...
 
Er, I guess I could actually fit lie theory in... I'd be sacrificing modern diff geo for classical diff geo though. :p
and the group theory course of course only talks about representations of finite groups.
 
@kylecampbell Finite groups can also appear in physics (e.g. crystal point groups or any other discrete symmetries) and their representations theory is a good preparation for Lie theory - many of the formulae are "just" the sums from finite group theory turned into integrals
 
oh interesting...
well, so if I could fit it in, lie theory + diff geo (with the former having a pre-req of groups) would probably be nice
I guess that makes sense that they would "just" turn into integrals!
 
9:11 PM
I haven't seen this before. A question that's basically a screenshot of an existing question. :facepalm: physics.stackexchange.com/questions/477448/…
 
9:56 PM
@kylecampbell The permutation group comes to my mind as particularly important.
@NovaliumCompany "Reasonable people adapt themselves to the world. Unreasonable people attempt to adapt the world to themselves. All progress, therefore, depends on unreasonable people."
George Bernard Shaw
 
10:30 PM
It's unusual for Ben to answer non-mainstream questions physics.stackexchange.com/questions/477479/…
 

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