The h Bar

John Duffield

9:02 PM

Does anybody know of any articles or texts that describe How a magnet works ?

Sir Cumference

@JohnDuffield easyscienceforkids.com/all-about-magnetism

That's an article

@JohnDuffield Ok, is topology useful for cosmology

Anonymous

@SirCumference Heh :P

Anonymous

Explaining (why) magnetism isn't an easy task. There have been hundreds of papers on the topic and still people are working on it.

Anonymous

I mean of course you'd find the generic Wikipedia level answers if you dig the net a bit.

0celo7

@SirCumference explain how

John Duffield

9:12 PM

@SirCumference : no, topology is not useful for cosmology. But it is useful for electromagnetism and quantum field theory. See TQFT. PS: that kiddies article doesn't explain how a magnet works at all.

ACuriousMind

@Blue The problem is that "why magnetism" is an ill-formed question to begin with (as are most "why" questions).

John Duffield

Doublepost deleted

Anonymous

@ACuriousMind Yeah, that is true

John Duffield

HOW A MAGNET WORKS

To understand how a magnet works, you need to understand that the electron doesn’t have an electric field or a magnetic field, it has an electromagnetic field. In fact it is electromagnetic field. We made it in gamma-gamma pair production, such that a 511keV electromagnetic wave is...

Anonymous

I think John Rennie had a good answer on this, I can't find it now

Anonymous

9:16 PM

At some level though, one has to take the things on faith, like most other things in physics

John Duffield

No you do not.

Faith. FFS.

ACuriousMind

@Blue It's not faith that physics relies on - it's experimental facts.

Anonymous

@ACuriousMind Those two are equivalent :P

ACuriousMind

Ahahahahaha, very well then

Anonymous

Your faith is based on experimental facts

Anonymous

9:18 PM

Magnetism

Magnetism is a class of physical phenomena that are mediated by magnetic fields. Electric currents and the magnetic moments of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments. The most familiar effects occur in ferromagnetic materials, which are strongly attracted by magnetic fields and can be magnetized to become permanent magnets, producing magnetic fields themselves. Only a few substances are ferromagnetic; the most common ones are iron, nickel and cobalt and their alloys. The prefix ferro- refers to iron, because permanent magnetism was...

Anonymous

The Wiki page is not bad

ACuriousMind

@Blue I think you mean "belief", not "faith". "Faith" usually denotes religious beliefs.

Anonymous

@ACuriousMind Reasonable, yes I agree

John Duffield

When you look into why a boomerang flies in a circular path, you soon find that it’s because of gyroscopic precession. Then it’s the work of but moments to find articles such as chapter 15 of Nicholas Turro’s Modern Molecular Photochemistry. In section 6 he says this: “Since the mechanics of the precessional motion of a gyroscope in the presence of gravity are of the same mathematical form as the mechanics of a

magnetic moment associated with a spinning charged body in the presence of a magnetic field , we postulate that the vector due to the magnetic moment of the quantum magnet undergoes precessional motion in an applied magnetic field”.

Sir Cumference

@JohnDuffield Ok is abstract algebra helpful

John Duffield

9:21 PM

@SirCumference : sure it is.

Secret

Sir: It depends on what aspect of abstract algebra you are talking about

0celo7

algebra is useless

@ACuriousMind right

Sir Cumference

@Secret I mean, is a course or two in abstract algebra likely to help a lot with cosmology?

John Duffield

@SirCumference : algebra is helpful. I'm not so sure about abstract algebra. If it's totally abstract and there's no application at all, I don't know what it's helpful about.

Sir Cumference

;-;

John Duffield

9:23 PM

I know how a magnet works.

ACuriousMind

@0celo7 Yes. Groups never play a role in physics /s

0celo7

@SirCumference Arguing against John (Duffield) is pretty hard, he's a lot smarter than you (or me)

2

John Duffield

When the particle is going around and around in a uniform magnetic field, there’s no net force on the particle. There’s a turning force, a torque, but this is symmetrical, and the motion of the particle is uniform. See Magnetic Torque and Magnetic Force from Michael Salvati at NYU physics for more about this. You can read that “in a uniform magnetic field there is no net force on the particle, but there is a torque and the angular momentum will, in some sense, precess about the magnetic field”.

Secret

@SirCumference That I am not sure, because I don't recall seeing even groups often in cosmology

Sir Cumference

@Secret Aw come on

John Duffield

9:24 PM

@ACuriousMind : sure thing. Those aren't prepared posts per se, those are excerpts from How a magnet works. Something I wrote.

Sir Cumference

Doesn't topology deal with manifolds?

0celo7

It is

ACuriousMind

@JohnDuffield It is clear you are just posting prepared posts on the topic of magnetism instead of having a conversation. This is not engaging in good faith, stop it.

Sir Cumference

And manifolds are supposed to be a big deal in GR

0celo7

@SirCumference wants to prove you wrong

Sir Cumference

9:25 PM

@0celo7 Wait what?

Secret

though I would imagine if you work with some kind of theoretical particle physics cosmology like one of my physics professor did as her research, then you will need at least a lot of groups

Sir Cumference

No, I just asked a question

Secret

but experimental cosmology? I will need to check

Sir Cumference

Ah, no, I only care about theoretical cosmology

The cool (jobless) stuff

bolbteppa

Feynmann explains to Shaggy how magnets work

►

Secret

9:26 PM

1

Q: Abstract Algebra in Relativity and Cosmology?

Is Abstract Algebra useful in theoretical Relativity and/or Cosmology? If so can anyone give me some examples or point me towards a good book with that emphasis if it is one? Thanks in advance.

Anonymous

@SirCumference Just become Hawking

Sir Cumference

@Blue ...in what regard?

ACuriousMind

@Blue Don't tell other users to die :P

Sir Cumference

I was thinking "get ALS", but yeah, death is also bad

Anonymous

@SirCumference Start writing pop science books :P

Sir Cumference

9:27 PM

@Blue Ok good

Anonymous

Cosmology is the best topic to attract laymen to physics

0celo7

my thesis will attract laymen to mathematics

Sir Cumference

Meh, I want to expand the frontier of human knowledge

Secret

@0celo7 looking forward to it

0celo7

Sir Cumference

9:28 PM

Not explain the known to laymen

0celo7

clearly good stuff

John Duffield

@ACuriousMind : sure thing. Note that those aren't prepared posts, those were excepts from one of my "physics detective articles" called How a magnet works. I ended it with what I think Feynman should have said in the famous interview.

bolbteppa

What should he have said?

Secret

JohnDuffield, vzn: The Labs are currently researching on Shadowbanning circumvention. It is a hard topic but if possible, anti-ghosting, which is one of the lamest way to handle a problem, will become possible at a global scale

ACuriousMind

@JohnDuffield I'm not interested in where it's from - but asking about a topic and then copy-pasting your responses instead of actually responding to other users shows the question was not asked with any interest in the responses to it, i.e. not in good faith.

John Duffield

9:31 PM

@bolbteppa : ACM says I mustn't post pre-prepared stuff. l

0celo7

@ACuriousMind must one act in good faith, even when the others are known to be wrong?

Sir Cumference

Sigh, fine! @JohnDuffield What math beyond ODE stuff is useful for (theoretical) cosmology, or GR in general

This is the last time I'll ask the chat since I'm practically out of time to figure this out

bolbteppa

You can state the jist of it in a quick sentence without copy-pastaing a wall of text

John Duffield

@SirCumference : sorry, I don't know. IMHO reading the Einstein digital papers and understanding what he was saying is the most useful thing.

Sir Cumference

Wait what?

Anonymous

9:33 PM

@SirCumference I must say, you should find someone else to give you math advice...

Sir Cumference

@Blue Sigh, I've asked all the mathy people here

Anonymous

Or cosmology advice..whatever

0celo7

@SirCumference have I not told you

Sir Cumference

@0celo7 Yeah, ik. But I'm getting other opinions. You only mentioned "Calculus on Manifolds" and maybe some basic differential geometry

Sigh, tired

John Duffield

@SirCumference : if you read the Einstein digital papers you know how gravity works, then you can apply that to a black hole, and because the universe is sometimes likened to a inside-out black hole, you can apply it to that too.

bolbteppa

9:34 PM

What do you mean by abstract algebra in general relativity

0celo7

if you learn my thesis you'll be ready

Secret

I supposed you all have asked Slereah? He pretty much into the really crazy things in GR?

Sir Cumference

@JohnDuffield I want to get a career in cosmology. Reading a few papers isn't sufficient.

Anonymous

Why not talk to actual cosmologists? Go and talk to the cosmologists at your college. They're the best people to guide you

Secret

^ that also

John Duffield

9:35 PM

@SirCumference : understanding will help.

bolbteppa

You can frame things in terms of rings, fields, modules, but you are just using some basic abstract algebra definitions, until you go really deep you wont be using abstract algebra

ACuriousMind

@0celo7 That highly depends on what you mean by "act in good faith". You shouldn't e.g. insult bad faith actors, or deliberately bait them into pointless discussions for your amusement, but you aren't required to assume good faith on their part either.

Sir Cumference

I emailed a theoretical cosmologist at my uni. He said "I think every physicist should know the basic undergraduate-level calculus, differential equations, and complex analysis. General relativity also involves differential geometry, but we usually teach what you need to know in GR classes.

Cosmologists are increasingly reliant on sophisticated statistics, computational techniques, and big data. So if you’re looking for classes outside PHA that might be worth taking, you might want to browse some of those"

Anonymous

@SirCumference Pretty solid advice I must say.

Sir Cumference

Though that seems more like experimental stuff

Anonymous

9:36 PM

Consider talking to a few more

bolbteppa

Honestly, it's pretty bizarre to be worrying about abstract algebra in general relativity

Anonymous

And decide what best suits you

Anonymous

Maybe take part in research and see if you even actually like real cosmology research

Sir Cumference

@0celo7 Wait what?

0celo7

You should talk to him.

He probably knows GR very well.

Secret

9:38 PM

@bolbteppa I think I saw groups more often than other algebraic structures in cosmology. That said, my only source of knowledge is pretty much my lecturer back in my undergrad who researches on GR cosmology stuff

bolbteppa

@JohnDuffield nobody can answer the why questions to the level you're asking, if you go back to old papers and expect answers you are fooling yourself, they had ideas formulated before even the knowledge of the weak force or what relativity does to the idea of elementary particles, it's not for lack of trying, but you don't know how to derive any of the math used to discover/predict the descriptions of these physical phenomena yet use it's language, that is faith/follow-the-leader behavior

John Duffield

@bolbteppa : Shrug. I know how magnet works. There's no faith to it at all. It's a question of taking things step by step.

bolbteppa

@Secret you might find some of the language of groups, rings, fields, and modules, but barely anything more than the definitions or basic ideas people pick up as they go

Secret

I see

0celo7

For some reason I thought he was at ETH.

But this guy is very big.

bolbteppa

9:45 PM

@JohnDuffield explain magnets in a sentence or so, just the jist, lets see if you use any weasel words or hand-waving or nonsense

Sir Cumference

@0celo7 Come on bro, stop mentioning the profs here

0celo7

What does that mean

Sir Cumference

Again, I would've preferred if my uni was kept private

0celo7

Did he give you a shitty grade

Sir Cumference

No, as in I'm not too fond of it being made public

Anonymous

9:46 PM

@bolbteppa Give it a rest already :P

0celo7

You're one of a billion undergrads there. I don't see an issue

It's not as if I have a bot looking in the student directory right now

Sir Cumference

Please don't bring this up again...

ACuriousMind

@0celo7 When people ask you to be careful with potentially personally identifying data, the right thing to do is to simply oblige.

3

Sir Cumference

Just in general, I prefer to keep my personal life off the internet

0celo7

@ACuriousMind I am obliging

I even deleted the guy's name

Secret

9:50 PM

40

A: Is learning (theoretical) physics useful/important for a mathematician?

It is certainly possible to study all kinds of topics in pure mathematics without any knowledge of physics, because you will always find literature/researchers who are used to explain the key concepts to fellow mathematicians without any knowledge in physics. But here are some examples of useful...

Note there is no set theory on that list

ACuriousMind

@0celo7 Yes, alright :) I'm just saying that this is an issue that's really up to everyone themselves - obviously you and I care less about our anonymity than SirCumference or e.g. Qmechanic - and it's little use to argue about it.

Secret

Probably the only domain of maths that will remain pure forever due to physical infinities still not being found

John Duffield

@bolbteppa : I can't explain it in a sentence or two. I have to explain what an electromagnetic field and what an electron is, then explain how a magnet's magnetic field is what's left over when most aspects of two electromagnetic fields cancel, then I have to explain why an electron goes round in circles in a uniform magnetic field, then why it exhibits a drift in a non-uniform magnetic field,

then I have to explain why a positively-charged particle goes the other way, then I have to step up to an array of copper ions and forces wherein every action has a reaction, then to the current in the wire, then to two currents in two wires, then we bend the wires to make a pair of solenoids, then we liken them to bar magnets. It's 3312 words.

Sir Cumference

@ACuriousMind Would you mind deleting other mentions of the people at my uni?

0celo7

lol

Sir Cumference

9:52 PM

@0celo7 Come on man... >_>

bolbteppa

What is an electromagnetic field then, in a sentence

0celo7

@SirCumference You should be worried, actually.

I think @diobuceulb might come find you now

He's a bit obsessed

Sir Cumference

Very funny...

ACuriousMind

24 messages deleted

Sir Cumference

@ACuriousMind All right, thanks a lot

0celo7

9:53 PM

look, just talk to JS. He can tell you all the math you need to know

Sir Cumference

He's a mathematician (analyst I think?), not a cosmologist

0celo7

yes he's an analyst

but analysts know everything about physics

Sir Cumference

@0celo7 ??

ACuriousMind

@SirCumference Well, @0celo7 is also a mathematician, so of course he'll give you the mathematical viewpoint on it. For a more "typically physical" perspective, you might want to ask @Jim

Sir Cumference

0celo knows a lot about math, but I don't know if I'd call an undergrad a mathematician...

0celo7

9:55 PM

burn

Anonymous

lol

Sir Cumference

That's not a burn >_>

Anonymous

I think you're worrying too much

John Duffield

@bolbteppa : it's not totally unlike a gravitomagnetic field. See this NASA article. Note this: "But if space is twisted, the direction of the gyroscope's axis should drift over time".

bolbteppa

Weinberg's Cosmology and GR are roughly probably the most mathematically intense you'd want to go before doing all the Penrose/Hawking global stuff (if even) I'd say

Anonymous

9:56 PM

Just learn the basic things first

ACuriousMind

@SirCumference I don't care about credentials, really. But I have no doubt that @0celo7 is a mathematician.

Sir Cumference

Well, I wouldn't call a junior Physics major a "physicist"

ACuriousMind

@SirCumference Not any junior Physics major, no.

Anonymous

@SirCumference We're looking at inclination/disposition

bolbteppa

@JohnDuffield ahaha... come on, what is an electromagnetic field, in a sentence or so?

0celo7

9:58 PM

@bolbteppa connection in a U(1) bundle!

bolbteppa

In other words, a vector field...

John Duffield

@bolbteppa : I'm not kidding. It's a place where space is twisted.

ACuriousMind

@SirCumference Puzzle question: I have a Master's in Physics, but am working as a software engineer and have no intention to do physics research. I answer physics questions on the internet in my spare time and herd a bunch of ~~cats~~ physicists in a chatroom. Am I a physicist?

Sir Cumference

Well, I don't know how much 0celo knows compared to a professional, so I'd just hesitate to use the term "mathematician"

John Duffield

Anonymous

10:01 PM

@SirCumference It depends very much on how you define "mathematician". ACM is using it in a more philosophical sense

Sir Cumference

@ACuriousMind Well having a Master's and being an undergrad are different things. One is a degree that indicates you've learned quite a lot

I'm not saying 0celo doesn't know his math, I just hesitate to call people good at math "mathematicians" when they are at the undergraduate level

ACuriousMind

@SirCumference Aside from specialized knowledge in the fields of string theory and homological algebra, I acquired most of my knowledge in undergrad :P

Sir Cumference

There's a massive gap in knowledge between professionals and undergraduates

Anonymous

@SirCumference That's totally reasonable

bolbteppa

@JohnDuffield man seriously, that is gibberish, you're saying the electromagnetic field is the place where space is twisted, and you justify it by a bunch of arrows representing a field in flat un-twisted space, come on...

ACuriousMind

10:02 PM

And I'm not saying you should start calling every math undergrad a "mathematician"

Secret

> There's a massive gap in knowledge between professionals and undergraduates

ACuriousMind

But there are people with master's degrees in physics who have forgotten almost everything (I know, I work with some :P). Credentials are not the only way to determine whether someone knows their stuff or not

Sir Cumference

@Secret Mathematics is one of the most difficult fields for undergrads to do research in, since the amount they are expected to know is usually graduate level

bolbteppa

The difference is doing original research, i.e. the thing that forces more than half of phd students to drop out over, and more not finish etc...

ACuriousMind

And, in fact, this "just an undergrad" attitude is representative of a general tendency to dismiss younger/inexperienced people regardless of their actual aptitude/knowledge.

John Duffield

10:06 PM

@bolbteppa : I'm not kidding. Einstein described a field as "a state of space". Heaviside came up with gravitomagnetism as an analogy of electromagnetism. NASA talked about twisted space. I didn't invent those vector field pictures.

Sir Cumference

@ACuriousMind True, credentials aren't the only way. But they're a relatively safe way, in my opinion. It's hard to gauge how well someone truly knows mathematics, even if they do know an impressive amount of math for their age

Secret

in today's society, even high schoolers probably knew a bit more than the undergrads because they are so keen to learn (it's just that public exam systems then scares them away)

Sir Cumference

That's why I'm hesitant to use the term "mathematician" in this case

0celo7

I can't tell if @SirCumference is trying to roast me or just being his usual ditsy self.

ACuriousMind

@SirCumference I wish I had your faith in the reliability of credentials :P

Secret

10:07 PM

I once talked to some guys who mentioned about how they used to love maths until the memorisation focused high school public exams turn them away and not explaining the why until uni

Sir Cumference

@0celo7 I guess the latter is more accurate

Secret

Somehow the public exams have to turn from memorisation based to conceptual based like uni exams

Sir Cumference

@ACuriousMind Ah come on, I'm not saying a degree is necessary to be called a "mathematician" or "physicist". I'm just saying the knowledge gap between a professional and a graduate student is much smaller than that between a professional and an undergrad

ACuriousMind

Or, rather, I wish credentials were actually as reliable as you think they are...

Sir Cumference

Whereas I can confidently call a professional a "mathematician", it's difficult to say whether an undergrad can be called one

This is just my opinion

0celo7

10:08 PM

I think ACM is subtly saying that I'm a genius and you should be nicer to me because I'll own you one day. Maybe.

ACuriousMind

@SirCumference And I say that "an undergrad" or "a graduate" are averages with such large standard deviations that one cannot make any useful generalization at all

bolbteppa

@JohnDuffield Einstein and Heaviside literally could not give a description of the electromagnetic field which took account of it's behavior with respect to elementary particles, i.e. the modern understanding, you are completely fooling yourself with these classical flawed pictures

Sir Cumference

@ACuriousMind I guess. To be honest the term "mathematician" is somewhat vague, I just associate it with the ability and knowledge to perform research

ACuriousMind

@0celo7 I've been called a genius too often by overly excitable people to use that term to describe others :P

bolbteppa

@JohnDuffield also you egregiously misinterpreted your article, it's talking about earth being so large it appreciably curves spacetime, and then a gyroscope behaving differently than it usually does due to the earths magnetic field in curved spacetime, what you just said is no different to me saying apples explain the moon because frogs, just madness

John Duffield

10:11 PM

@bolbteppa : I'm not. Electromagnetism is not some classical flawed picture.

vzn

@bolbteppa he has many credible refs, have found some on my own, if youre really serious the info is "out there," its not exactly what is taught in textbooks, its new physics. he deserves some credit for going back to original refs. its not a bug its a feature. its that old expr about pouring new wine into old bottles etc...

Sir Cumference

All right, I need to get back to work

Later

bolbteppa

Absolute madness, seriously

0celo7

holy shit @vzn and @JohnDuffield. Can you name a more iconic duo

5

ACuriousMind

@SirCumference On a Sunday??

0celo7

10:11 PM

@ACuriousMind I've been working since I got up

vzn

lol

Sir Cumference

@ACuriousMind Yep, break's about over and I'm a chapter behind in algebra

0celo7

Some people have lots of stuff to do

Sir Cumference

Considering the horrendous quality of this book, I'm gonna be spending a few hours trying to figure this out

ACuriousMind

The best thing about not being in academia is having the weekends off. Seriously.

2

John Duffield

10:12 PM

@bolbteppa : gravitomagnetism was developed by Heaviside as an analogy of electromagnetism. That's not some madness to do with the moon and frogs.

0celo7

@ACuriousMind I'm trying to finish the thesis so you can start reading

ACuriousMind

(inb4 someone says that there are other jobs who have to work on weekends, too: Yes, I'm aware of that)

Sir Cumference

@ACuriousMind Weekends translate to "more time to actually get studying done", in my mind

Weekdays are hectic

Anonymous

I'm memorizing stuff about drilling machines. What could be worse on a Sunday midnight

Sir Cumference

Actually having free time to dedicate to my studies, uninterrupted, is much better

ACuriousMind

10:13 PM

@Blue Are you in my timezone? oO (It's midnight here now :P )

Anonymous

@ACuriousMind I actually don't know the time

Anonymous

It's around 2-3 here I guess

Anonymous

Ah, lol, 3:44 am

0celo7

@ACuriousMind you're the only one who apparently never worked

Anonymous

It's Monday already

ACuriousMind

10:15 PM

@0celo7 It's true, I was a lazy student

John Duffield

@bolbteppa : what's madness is that you can't show me a depiction of the electromagnetic field. Maxwell unified electricity and magnetism a hundred and fifty years ago, John Jackson said "one should properly speak of the electromagnetic field Fμv rather than E or B separately", but you can't show me a depiction of it.

bolbteppa

@JohnDuffield This gravitomagnetism stuff Heaviside was talking about is a bunch of analogies based on the fact both gravity and electromagnetism are fields which satisfy field equations, you can model the correct theory of GR on EM, this is literally why people predicted gravitational waves should exist, but again, this is all classical thinking, quantum mechanics destroys all of this thinking

0celo7

@ACuriousMind this 156 page thesis isn't going to edit itself

John Duffield

@bolbteppa : quantum mechanics does not destroy all this thinking. Trust me, I've spent months digging into that.

bolbteppa

@JohnDuffield 'trust me', my god, more of this anti-science thinking I see

ACuriousMind

10:17 PM

@0celo7 Yeah, I know

vzn

anyone here who thinks current laws of physics need zero revision plz raise your hand :P

ACuriousMind

I'm not telling you to stop working on it, just expressing my concern that working all Sunday is considered par for the course.

John Duffield

@bolbteppa : I don't do anti-science thinking. Now, you show me a depiction of the electromagnetic field, and when you can't, ask yourself why not.

vzn

lol "QM destroys all this thinking" :P

Anonymous

@JohnRennie My PC clock suddenly changes to the UK timings, and then again back to the Indian standard time. This is weird. (On the Windows version you gave)

bolbteppa

10:19 PM

@JohnDuffield you said you knew what an electromagnetic field is, you justified yourself with (in the nicest interpretation, which is not deserved) a classical mechanics justification, so you basically just wrong by definition, and fooling yourself to pretend otherwise, you basically have to deny physics since the 1900's to pretend otherwise

ACuriousMind

@Blue Clearly, he built in a backdoor that allows him to control your PC.

John Duffield

@bolbteppa : I don't have to deny physics since the 1900s. Here's the 1929 article where Einstein described a field as a state of space: The History of Field Theory by Albert Einstein.

vzn

↑ lol anticrank collides with crank o_O

Anonymous

@ACuriousMind That's totally possible ;) I don't trust old Brit nutcases :P

bolbteppa

@JohnDuffield ah, an essay by Einstein before (or just about when) the electromagnetic field was even quantized, and completely ignores quantum mechanics, you keep admitting you're going off classical thinking as though this somehow says you're not...

vzn

10:22 PM

↑ dont throw the baby out with the bathwater o_O

0celo7

fuck the baby

ACuriousMind

@0celo7 Um. Maybe reconsider that message :P

0celo7

@ACuriousMind why

only a sicko could misunderstand it

vzn

the "baby" is so far unspecified & is a metaphor, aieee metaphors :P

bolbteppa

@JohnDuffield this is now two articles you justified yourself with that actually just show you don't even understand the articles meaning

vzn

10:24 PM

@bolbteppa hes wrong QED so what more do you have to prove?

John Duffield

@bolbteppa : I've got Einstein, Maxwell, Heaviside, Jackson, and NASA on my side. And Wikpedia: "Over time, it was realized that the electric and magnetic fields are better thought of as two parts of a greater whole — the electromagnetic field". Now, where's your depiction of the electromagnetic field?

ACuriousMind

@bolbteppa @JohnDuffield This discussion is clearly not productive. Why continue it?

9

John Duffield

@ACuriousMind : because it's physics, because it's interesting. And IMHO because it will be productive when the penny drops that bolbteppa can show me a depiction of the electric field, and the magnetic field, but not the electromagnetic field. IMHO that says something really important about electromagnetic unification. Or the lack thereof.

But if he doesn't want to talk about it any more, no problem.

OK, I have to go anyway. Nice talking to y'all. Goodnight.

bolbteppa

I just wanted to see what level of explanation he would give since he was so sure he could correct Feynman, to see him coming out with classical explanations when Feynman was going quantum, well, of course he would go classical and pretend Feynman was wrong

Secret

18 mins ago, by vzn

↑ lol anticrank collides with crank o_O

and yet there are no crank-tons produced

:P

On a more serious note, I wonder what a wave (and pure energy) version of a (anti)crank is like...

20

Q: Why does matter/antimatter only produce gamma rays?

According to wikipedia, all antimatter annihilation produces gamma rays (along with potentially other elements). Why specifically Gamma rays? Why not electromagnetic waves of other wavelength?

electromagnetic-radiation mass-energy antimatter neutrinos gamma-rays

a neutrino-crank will be one that is apathetic to (anti)cranks I think

Anonymous

10:43 PM

@bolbteppa I guess it's important to choose one's battles wisely. Trying to correct everybody on the internet will only cause one to drain their energy, without actually doing anything worthwhile. I'd probably give that advice to my former self, too.

Secret

Fun fact: I don't really spend time correct people: I let Nature to do the job

Because often when people who subscribed to beliefs that run counter to nature, they will die off because nobody can break laws of physics anyway...

ACuriousMind

@Secret ...have you even looked at the history of human beliefs before issuing that statement?

Secret

eh.. well I do have quite a bit of counterexamples:

3

Q: How are beliefs restricted by an objective reality?

Consider the following belief A human can survive if they don't drink water for 1000 days We knew from biology that this is practically improbable as there are very few people who can survive for 18 days without water (Andreas Mihavecz in 1979). However, there are also beliefs that are unr...

epistemology metaphysics belief

ACuriousMind

Believing in something that's not possible by physical laws is not an evolutionary disadvantage, unless you happen to believe you can magically outrun tigers.

vzn

note to all parties, public service announcement: JD is on the trail of a new fluid paradigm. he is correct in that it is hinted at in old classic physics papers by the pioneers, missed and/ or swept under rug by top physicists. the new paradigm does not arrive in complete form. it will require very sharp ppl to analyze and push it fwd in a mathematically rigorous way. there are already some major attempts along these lines last few yrs, quite a few already posted here! stay tuned! :)

Secret

10:47 PM

Acirousmind: yeah, the full picture is actually a bit complicated. It does seems nature have a the tendency to choose the middle ground of pretty much everything

bolbteppa

Oh man, haha

Secret

But in most cases, it is quite reliable e.g. we won't jump into magma because we knew it can kill us, for example

ACuriousMind

@vzn Take your conspiracy theories about top physicists sweeping truth under rugs elsewhere.

Anonymous

That ^

vzn

lol its not intentional by the physicsts, did not claim it was, putting words in my mouth etc

ACuriousMind

10:50 PM

Ah, of course you didn't say what you clearly said. Goodbye.

Secret

actually a more precise question: How many not so theoretical laws of physics which can kill us if we don't believe in them. I knew that killed by high voltage is one, touching very cold of very hot objects is another, but do they form the majority?

To define: Not so theoretical here means e.g. stuff that are encountered readily in everyday scenarios

ACuriousMind

@Secret That's not a very precise question. Newton's laws are "no so theoretical" in the sense that they govern all movement, yet Artstotle didn't die because of his lack of understanding of Newtonian physics.

Secret

hmm fair enough

bolbteppa

I think the problem is the inability to be happy with uncertainty in thinking that leads one to pretend they know everything and not care if they're shown to be wrong, people have tried to look into the biological/evolutionary link to this, it really probably could have been an advantage to be that way in the past

ACuriousMind

@Secret For the largest part of human history, humans had no notion of "laws of physics" as we understand them today. I believe your approach to this is fundamentally flawed by assuming people, especially ancient ones, think/thought about what happens around them in terms of "laws" one could or could not believe in.

I may well choose not to believe in Newton's laws yet my brain still intuitively predicts the trajectories of thrown objects correctly according to Newton's laws regardless of my "belief".

Secret

10:58 PM

I see...

0celo7

@ACuriousMind finishing this theses is the same feeling I get when a good game is about to end

ACuriousMind

@0celo7 I guess that means you enjoyed it :)

(Or did you mean you'll look back at the beginning and wish you'd have made different character development choices? :P)

vzn

11:26 PM

let see, search terms analogy electromagnetic waves fluids and where in all of cyberspace does google (AI) point to? lol result #2 Physics, +1 :P

9

Q: Analogy between fluid dynamics and electromagnetism

I've been reading a set of notes (Chapter 13 of Caltech Ph 136 notes from 2004, by Blandford and Thorne) that draw an analogy between fluid dynamics and electromagnetism, identifying the magnetic vector potential $\mathbf{A}$ with the velocity flow field $\mathbf{u}$, the magnetic field with vort...

electromagnetism fluid-dynamics

> the analogy appears to be mainly illustrative and not intended to be taken too far... lol

Secret

11:46 PM

These terms have really strange numbering on them

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