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Kenshin
Kenshin
11:11 AM
it's going to be 45 degrees Celcius in australia on the weekend
@skillpatrol why
do you?
 
skill patrol
skill patrol
Nope, just thinking about getting one.
 
user228700
@skillpatrol Nope.
 
Kenshin
Kenshin
@skillpatrol I recommend you don't get one
 
user228700
Also, @Kenshin: Hello :-) What to do in the summer? :'-(
 
Kenshin
Kenshin
it's not a financially sound decision
hello @Kaumudi.H :D
@Kaumudi.H in summer we swim at the beach
and go to the shops or the movie theatre where it's airconditioned
 
skill patrol
skill patrol
11:13 AM
It looks like the future of "computers."
 
Kenshin
Kenshin
or otherwise stay home in the aircon
@skillpatrol no way the interface is too small
 
user228700
@Kenshin Hmm, OK...
 
Kenshin
Kenshin
what @Kaumudi.H?
 
user228700
:?
 
Kenshin
Kenshin
what do you do ?
 
user228700
11:14 AM
Nothing, really.
 
user228700
I haven't had free summers in quite some time, now.
 
Kenshin
Kenshin
oh...
that's a shame
 
user228700
I've had classes during the summer in the past 3 years...
 
Kenshin
Kenshin
but you have the weekend free tho
I assume
what hours are classes in your country?
 
user228700
Nah, I had classes even on Sundays. Longer on Sundays, in fact--8 hours or so.
 
Kenshin
Kenshin
11:15 AM
wow
in Australia school is mon to friday 9 tiil 3
 
user228700
School is only during the week tho; 8-3.
 
Kenshin
Kenshin
that's gud
what is sunday school?
is that voluntary extra study?
 
user228700
It's not Sunday school, it's "coaching class" which yes, is voluntary.
 
Kenshin
Kenshin
how many people do that?
10%? 50%? 90%?
 
user228700
Millions.
 
user228700
11:17 AM
That would be about 70-80%
 
Kenshin
Kenshin
is that a necessity to remain academically compoetitive?
wow yeah taht is alot
 
user228700
Yep.
 
user228700
Well, it depends on the student, I suppose.
 
Kenshin
Kenshin
you guys must be really smart
 
user228700
But even if u don't attend classes, weekends aren't "free"...
 
Kenshin
Kenshin
11:18 AM
how come?
homework?
 
user228700
@Kenshin I really don't know about that.
 
Kenshin
Kenshin
but you do so much study, you will have alot of knowledge
 
user228700
@Kenshin If u don't attend classes, u must prepare at home, on ur own, u know...
 
Kenshin
Kenshin
too much
 
user228700
What is?
 
Kenshin
Kenshin
11:19 AM
study
too much work
 
user228700
Oh, right. Yes, sort of. I don't want to talk about it... (:-P)
 
Kenshin
Kenshin
lol k
u going to see this? @Kaumudi.H
 
user228700
No, I'm not going to watch "Beauty and the Beast" although I would love to. I'm watching the video x'D
 
user228700
Lol, there's even a hipogrifff in it!
 
Kenshin
Kenshin
lol yeah
fantastic film
 
John Rennie
John Rennie
11:33 AM
 
Kenshin
Kenshin
what is a better way?
 
skill patrol
skill patrol
^
 
Kenshin
Kenshin
I find light clocks to be a great way to introduce relativity to beginners as it allows a student to easily visualise the concept
 
skill patrol
skill patrol
Yes, the concept of "time" itself.
 
Kenshin
Kenshin
yes time is what clocks measure
 
John Rennie
John Rennie
11:36 AM
The only good way to understand SR is to understand that the proper time is an invariant - technically a Lorentz scalar - and given by the metric.
 
Kenshin
Kenshin
and what better clocks to use than light clocks
 
John Rennie
John Rennie
Once you understand that everything else follows naturally.
 
Kenshin
Kenshin
@JohnRennie perhaps, but I don't think this is a good approach for teaching someone for the first time
 
John Rennie
John Rennie
I disagree
 
skill patrol
skill patrol
Why?
 
John Rennie
John Rennie
11:38 AM
I think it confuses students and they never attain a decent understanding. At best they throw around factors of $\gamma$ in the vain hope the answer will drop out.
 
Kenshin
Kenshin
I think that's too big a generalization John
many students learn with light clocks initially and then later learn a more rigerous approach and don't throw around factors of gamma in vain
 
skill patrol
skill patrol
Einstein used them.
 
Yashas Samaga
Yashas Samaga
what happened to the best of PSE? lol
 
Kenshin
Kenshin
@YashasSamaga, right here, what do you need?
 
Yashas Samaga
Yashas Samaga
uhm
I meant the Best of PSE meta post
 
Kenshin
Kenshin
11:40 AM
oh I thought you meant the best of PSE
<-
 
skill patrol
skill patrol
Changing the pedagogy of SR is not going to be an easy task @JohnRennie
You can try :-)
 
John Rennie
John Rennie
SR pedagogy will have to manage without me. I'll just do my best to pick up the pieces here.
 
skill patrol
skill patrol
And we appreciate that.
 
skill patrol
skill patrol
11:56 AM
@JohnRennie why did university challenge get cancelled from 1987-92?
 
John Rennie
John Rennie
If you're interested the BBC did a documentary about University Challenge that is very interesting. It's be floating around on the Internet somewhere.
 
skill patrol
skill patrol
Ok.
 
John Rennie
John Rennie
From memory it was just that Bamber Gasgoine had been doing it for a long time and the show was getting a bit tired. The BBC revived it by getting Jeremy Paxman to host it. Paxman is a far more aggressive and spiky host than Gasgoine ever was.
 
skill patrol
skill patrol
Yes he is.
 
John Rennie
John Rennie
I don't watch it routinely, but I think it is a good show these days. It's always embarrassing how few of the questions I can answer :-)
 
skill patrol
skill patrol
12:00 PM
I like it when they do the alumni shows.
The pace is slower.
 
Balarka Sen
Balarka Sen
@Slereah A parametrization is a homeomorphism $\Bbb R^n \to U$. A chart is $U \to \Bbb R^n$.
Or at least that's the convention I use
But yeah some people like to call everything charts
 
Yashas Samaga
Yashas Samaga
1:00 PM
answers to old questions go unseen?
 
ACuriousMind
ACuriousMind
@YashasSamaga What do you mean?
 
Emilio Pisanty
Emilio Pisanty
Hey @Qmechanic, how come this got protected? Did it make HNQ or something?
because if yes, that's one more black mark on that algorightm
 
Yashas Samaga
Yashas Samaga
@ACuriousMind an upvote won't bring an old post to the active list, right?
answering a question momentarily brings an old question to the active list?
 
ACuriousMind
ACuriousMind
@YashasSamaga No; the active list shows new answers and edits to the question or one of the answers.
 
Yashas Samaga
Yashas Samaga
so those who always check questions using the "newest" tab will never see answers to the old questions
 
ACuriousMind
ACuriousMind
1:11 PM
Correct
If you want to see interesting answers the newest tab is rather useless
 
Emilio Pisanty
Emilio Pisanty
^ hence the existence of the active tab
 
Yashas Samaga
Yashas Samaga
some old answers never get upvoted
 
0celo7
0celo7
Hello
 
skill patrol
skill patrol
yo
 
Yashas Samaga
Yashas Samaga
hi
do I mark a question X as duplicate if another question Y has an answer which answers the question X?
question Y's title does not directly indicate that question Y answers the question X
 
ACuriousMind
ACuriousMind
1:25 PM
@YashasSamaga If the questions are so similar that every answer to one would also answer the other then marking as duplicate is justified. If it's just the case that that other question happens to have an answer that also answers the other, but the questions themselves are different, then they're not duplicate.
 
Yashas Samaga
Yashas Samaga
aw I am going to have declined flags now
 
ACuriousMind
ACuriousMind
Whether the title itself is similar or not is not that relevant.
 
Yashas Samaga
Yashas Samaga
the question Y asks around 8-9 questions
question X is a part of it
0
Q: Why are magnetic field lines closed?

V.KarthikIf there were two charges placed at a large distance, won't their (say) magnetic fields interact? What if that large distance is something like close to infinity? Even if they experience a feeble force from each other, doesn't that imply that the magnetic field lines are not closed, as the partic...

magnetic-fields magnetic-monopoles
^ question X
0
Q: What do we mean with magnetic monopole and dipole?

TheQuantumMan What do we mean with magnetic monopole and dipole? I can not find a way to relate magnetic monopoles and dipoles with electric ones. I do not understand their outcomes. Also,what is their role in Gauss' law for magnetism (the net magnetic flux through a closed surface is zero)? I read that the ...

electromagnetism classical-electrodynamics gauss-law magnetic-monopoles dipole
^ question Y
 
Emilio Pisanty
Emilio Pisanty
@YashasSamaga Don't worry about declined flags unless you have multiple instances with the same problem
 
Yashas Samaga
Yashas Samaga
I have 4 declined, 91 helpful
 
Qmechanic
Qmechanic
1:29 PM
@EmilioPisanty : I unprotected it for now. I didn't saw it in the HNQ, but OP has recently asked several poorly received basic kinematic questions that we don't want to linger on the front page.
 
Emilio Pisanty
Emilio Pisanty
@Qmechanic how does protection help with that?
 
Yashas Samaga
Yashas Samaga
does not allow new users to answer? most new users somehow will have 10 reps
 
Qmechanic
Qmechanic
@EmilioPisanty : Fewer answers.
 
ACuriousMind
ACuriousMind
@YashasSamaga You're fine. There's an annoying thing where an automatic block on flagging can kick in for relatively few declined flags, but generally, when in doubt, flag.
 
Emilio Pisanty
Emilio Pisanty
@Qmechanic I'm not sure it'll be effective at all, unless there is some specific risk of new/outside users answering.
 
Qmechanic
Qmechanic
1:33 PM
@EmilioPisanty : Well, maybe you are right. Anyway, basic questions seem to be more prone to new/outside users.
 
Emilio Pisanty
Emilio Pisanty
@Qmechanic No, I get what you're trying to do, it just doesn't square with what I normally think protection is for
 
0celo7
0celo7
@physics people. I'm pretty bad at physics. If magnetic field lines have to close, how do uniform magnetic fields work?
 
Koolman
Koolman
Can anybody explain me in this , that if I have done it correct or wrong
 
Secret
Secret
what David Z and dmckee discussed with me last year of a classical unreproducible real event (assuming the fluke is really not a fluke of course):
Also, there's a semi-famous experiment to look for magnetic monopoles that saw one signal of exactly the type they would've expected for a monopole within the first few hours of operation. And then never saw anything like it again. It was almost certainly a glitch, but it's kind of amusing to imagine that they really did see the one monopole in the Local Group right when they first turned their detector on... — Chad Orzel Nov 29 '10 at 0:40
 
ACuriousMind
ACuriousMind
@0celo7 There's a region where it's not uniform outside the uniform region.
 
0celo7
0celo7
1:40 PM
@ACuriousMind in experiment, sure
What about the ideal model
 
ACuriousMind
ACuriousMind
Well, theoretically, a uniform field doesn't have a source or sink either, so it's fine
 
Secret
Secret
it just go forever to infinity, and that does not need sources nor sink
 
Emilio Pisanty
Emilio Pisanty
@0celo7 they close "at infinity"
 
Yashas Samaga
Yashas Samaga
@0celo7 or in other words you can zoom in too much into a non uniform magnetic field
 
Emilio Pisanty
Emilio Pisanty
if you don't like that, that's what you get for pretending your experimental apparatus is infinitely big
=P
 
0celo7
0celo7
1:48 PM
@EmilioPisanty why does that mean?
 
Emilio Pisanty
Emilio Pisanty
@0celo7 doesn't mean anything =P, but people still say it
The real physics at work is the magnetic Gauss law, $\nabla\cdot\mathbf B=0$
 
Yashas Samaga
Yashas Samaga
@ocelo7 one of my answer explains why the magnetic Gauss law has a zero on the right hand side
I have provided a link somewhere above
If you know electrostatics, you can master magnetism in 10 minutes.
2
A: What do we mean with magnetic monopole and dipole?

Yashas Samaga What do we mean with magnetic monopole and dipole? I can not find a way to relate magnetic monopoles and dipoles with electric ones. I do not understand their outcomes. Luckily, there exists a truly amazing one-to-one correspondence between magnetism and electricity. Monopole in magneti...

because the equations are quite similar
it assumes that monopoles exist, explains how they "might" work then shows that they are consistent with the magnetic dipole framework
 
Emilio Pisanty
Emilio Pisanty
Also, regarding the relationship between field lines and the Gauss law:
13
Q: Why does the density of electric field lines make sense, if there is a field line through every point?

odgWhen we're dealing with problems in electrostatics (especially when we use Gauss' law) we often refer to the density of electric field lines, which is inversely proportional to the radius in the case of a single point charge (all field lines are directed radially). My question may sound dumb, d...

electrostatics electric-fields gauss-law
 
0celo7
0celo7
@EmilioPisanty I meant what, not why
 
Emilio Pisanty
Emilio Pisanty
@0celo7 so I imagined
 
0celo7
0celo7
1:53 PM
But that's a very physicsy thing to say
 
Emilio Pisanty
Emilio Pisanty
@0celo7 that's a red flag that you shouldn't necessarily take it literally
 
obe
obe
hey
 
0celo7
0celo7
@ACuriousMind After some meditation, I have concluded that the usual 1 = integral X eigenkets is nonsense
And the only reason physicists use it is because of Dirac notation
 
Secret
Secret
Actually, is it possible that monopoles are so diluted in the universe that we can only hope to amass enough data to claim a discovery only many centuries later?
 
Yashas Samaga
Yashas Samaga
It'd be awesome if someone finds a monopole.
 
0celo7
0celo7
2:01 PM
@ACuriousMind Because what other use does it have than $\langle\phi|\psi\rangle=\int\phi^*\psi \,dx$?
but that's the definition of $\langle\cdot|\cdot\rangle$
 
ACuriousMind
ACuriousMind
Yes, you can stop thinking about position eigenkets and that particular resolution of the identity if you stop using position eigenkets altogether and work with $L^2(\mathbb{R}^n)$ directly.
 
Emilio Pisanty
Emilio Pisanty
oooooooh, this is a nice LaTeX template
 
0celo7
0celo7
@ACuriousMind what else are you gonna work with?
Use Stone-von Neumann to rotate to $L^2$
 
ACuriousMind
ACuriousMind
@0celo7 The physicists using Dirac notation usually have this notion of the state space itself being "abstract" - they don't want to commit to the position representation a priori. However, you are right that once one has Stone-von Neumann choosing $L^2$ is natural.
Alas, no one shows Stone-von Neumann :P
 
Slereah
Slereah
2:29 PM
For some reason in non-relativistic QFT, people mostly use braket notation when angular momentum is involved
since it's a quicker proof with abstract Hilbert space than with spherical harmonics
Also the SHO
Because people don't know L'hermite polynomials
Basically anytime a special function is involved, people switch to brakets
 
0celo7
0celo7
@ACuriousMind It's in Hall's book...
 
Yashas Samaga
Yashas Samaga
2:50 PM
0
A: Heat flux over a surface

Yashas Samaga The source of the radiation is above O. Construct 3 more squares which are identical to $OBCD$ as shown in the diagram. Similarly, construct 6 big squares to form a cube. The source of radiation is at the center of the cube, right above O. So each face of the cube would get $\frac{1}{6}$ of...

my cube lol
 
Slereah
Slereah
One thing that annoys me about Jost is that he introduces notations he doesn't define
I can guess but who knows
How does he define $\lim_{x \to a, x < a}$
Do we only consider sequences with members $<a$?
 
0celo7
0celo7
Yes
It's the left limit
@BalarkaSen I have the GMT book
@ACuriousMind @Slereah I need some good energy for this circuits test
@obe
 
Slereah
Slereah
3:07 PM
Tylenol
 
Balarka Sen
Balarka Sen
3:24 PM
@0celo7 Neat
 
0celo7
0celo7
3:51 PM
@ACuriousMind @BalarkaSen "Geometric measure theory could be described as differential geometry, generalized through measure theory to deal with maps and surfaces that are not smooth, ..."
So why doesn't it show up in your strange manifolds
 
ACuriousMind
ACuriousMind
Maybe it does, but I already told you I don't care about measures
 
Slereah
Slereah
I think you need some measure theory for GR causal structure?
The time function in GR is a measure, IIRC
 
0celo7
0celo7
Geroch's theorem uses a Borel measure
Nothing fancy
 
Slereah
Slereah
more like boring measure
It is a measure of HOW MUCH SPACETIME DO YOU HAVE
Is it
a lot of spacetime
Or a little spacetime
 
Bernardo Meurer
Bernardo Meurer
Wat
 
0celo7
0celo7
3:57 PM
it's actually a probability measure, if I recall correctly
i.e. $\mu(\mathscr M)=1$
 
Slereah
Slereah
Well probability measures are measures
 
Balarka Sen
Balarka Sen
Measure theory can be done on manifolds, I believe, @0celo7
 
Yashas Samaga
Yashas Samaga
0
A: Does law of inertia has anything to do with speed of light?

Yashas SamagaThe rest mass of photons is zero. Hence, they do not have any inertia. Asking how do you accelerate a photon is a meaningless question. The photons must travel at the speed of light. It is a fact.

And their momentum is due to kinetic energy provided to them by source
 
Slereah
Slereah
I would like 1 spacetime, please
 
Yashas Samaga
Yashas Samaga
is that statement accurate or correct?
 
Slereah
Slereah
3:58 PM
1 spacetime worth of spacetime
 
Yashas Samaga
Yashas Samaga
Kinetic energy of photons, it is interesting...
 
0celo7
0celo7
@BalarkaSen measure theory can be done on any set :P
 
Slereah
Slereah
what about on a category
 
Balarka Sen
Balarka Sen
That's not the point.
 
Slereah
Slereah
Can u measure a category
 
0celo7
0celo7
3:59 PM
@BalarkaSen Then I don't know what the point is
if you're talking about making the volume form into a measure, yes
there are ways of doing that
 
Balarka Sen
Balarka Sen
@0celo7 You want to do measure theory on a manifold as a set? Forgetting the smooth structure, hell, the manifold structure?
That's boring and nobody would care
 
0celo7
0celo7
@BalarkaSen I am very familiar with the natural measure on a Riemannian manifold
I am writing a survey on Sobolev spaces and elliptic regularity on Riemannian manifolds
 
Slereah
Slereah
@0celo7 : is the secret...
...partition of unity?
 
0celo7
0celo7
dammit, you discovered my secret!
 
Slereah
Slereah
It is always partition of unity
 
Balarka Sen
Balarka Sen
4:01 PM
The point is still not that. Riemannian metric gives a measure, but a measure on a manifold is a much weaker concept than a Riemannian metric.
 
ACuriousMind
ACuriousMind
@YashasSamaga Well, photons do have energy according to $E=pc$, I guess that's what the answer is trying to say
 
Yashas Samaga
Yashas Samaga
Yea but he said kinetic energy...
I feel weird though
 
Bernardo Meurer
Bernardo Meurer
Energy is a lie
 
ACuriousMind
ACuriousMind
Well, I'm not sure it's useful to call that kinetic energy, but I don't see why it would be wrong either. The partitioning of energy into different "kinds" is arbitrary anyway
 
0celo7
0celo7
@BalarkaSen This book is citing Federer on page 3. I think I'll be getting it.
 
Balarka Sen
Balarka Sen
4:03 PM
have fun with that
 
0celo7
0celo7
@BalarkaSen What kind of measure do you want to put on the manifold?
 
Bernardo Meurer
Bernardo Meurer
@0celo7 He recently beat Nadal again
 
0celo7
0celo7
@BernardoMeurer ???
 
DanielSank
DanielSank
Hi everybody.
 
Bernardo Meurer
Bernardo Meurer
@0celo7 ^
 
0celo7
0celo7
4:05 PM
Wrong Federer.
 
Balarka Sen
Balarka Sen
One that would be, in some sense, compatible with the smooth structure. Eg, that gives the standard measure on each chart and doesn't change if you switch charts
 
0celo7
0celo7
@BalarkaSen You'd need a density on the manifold to do that.
 
Balarka Sen
Balarka Sen
But I don't actually know much about the story in manifolds.
 
0celo7
0celo7
You need to counteract the Jacobian that pops up in the transformation formula.
 
Balarka Sen
Balarka Sen
@0celo7 I have heard the word, but I dunno what that means
 
0celo7
0celo7
4:07 PM
@BalarkaSen Basically a scalar that gives a factor of the inverse Jacobian when you compose with a diffeomorphism
Like $\sqrt{\det g}$, the determinant of the metric.
@BalarkaSen I have another test in 8 minutes
I can explain later
 
Balarka Sen
Balarka Sen
So it's some sort of a form?
Ok, sure.
 
Restioson
Restioson
4:55 PM
Hi! In our high school physics lesson today, we looked at how the pressure differentials which happen when a jet plane travels at the speed of sound (in air at 20 degrees) can distort (at least) visible light. So, I was wondering whether this can also distort radio waves, and also whether people ever use pressurised chambers as lenses (the distortion was compared to a a lens)
 
Bernardo Meurer
Bernardo Meurer
Hmm, I guess the length of radiowaves will make the effect minimal
Dunno
 
anonymous
anonymous
@Restioson This might be related en.wikipedia.org/wiki/Shadowgraph
Shadowgraph
Shadowgraph is an optical method that reveals non-uniformities in transparent media like air, water, or glass. It is related to, but simpler than, the schlieren and schlieren photography methods that perform a similar function. Shadowgraph is a type of flow visualisation. In principle, we cannot directly see a difference in temperature, a different gas, or a shock wave in the transparent air. However, all these disturbances refract light rays, so they can cast shadows. The plume of hot air rising from a fire, for example, can be seen by way of its shadow cast upon a nearby surface by the uniform...
 
0celo7
0celo7
@BalarkaSen Still here?
 
anonymous
anonymous
And yeah, if the phenomenon occurs with normal visible light then it should also happen with radio waves
@Restioson
 
0celo7
0celo7
@JohnDuffield Wow, 234 days left.
Can't wait!
@BalarkaSen You can always write an $n$-form as $f\, dx^1\wedge\cdots\wedge dx^n$. That $f$ out front is a "scalar density."
The point is that when you transform coordinates, the coordinate representation of $f$ gives a factor of the (inverse) Jacobian
Thus, given such an $f$, and a partition of unity $\phi_i$, you can define a measure on $M$ by $$dv=\sum_i f(x)\phi_i(x)\, dx$$ in the sense of (measure-theoretic) densities, where $dx$ is the Lebesgue measure in the chart.
By "measure theoretic densities," I mean that the measure $v$ is defined by integration with respect to $dv$.
The $\sigma$-algebra you get contains the Borel sets and is complete.
 
Balarka Sen
Balarka Sen
5:07 PM
Ah, I see. That makes sense.
 
0celo7
0celo7
@BalarkaSen Since $\sqrt {g} \,dx^1\wedge\cdots\wedge dx^n$ gives a "natural" density on a Riemannian manifold, that's the way we usually integrate/do measure theory.
 
Balarka Sen
Balarka Sen
Right.
 
0celo7
0celo7
@BalarkaSen You also need $f$ to be nonnegative for $v$ to be a measure, of course.
And Lebesgue-measurable in each chart.
 
Slereah
Slereah
is there a specific unit of spacetime volume, I wonder
A unit for $m^3 s$
Let's call it a... hilbert?
I dunno
 
0celo7
0celo7
Where did you get that from?
 
Slereah
Slereah
5:13 PM
Who introduced spacetime volumes
I am inventing it
 
DanielSank
DanielSank
@JohnRennie you may also find that amusing.
 
Restioson
Restioson
And what about using pressurised chambers as a lenses?
 
John Rennie
John Rennie
@Restioson Anything that produces a refractive index change will refract light, so you could use a pressure vessel as a lens. Compressing the air will increase the refractive index. I guess the question is why would you?
 
Restioson
Restioson
Why not
you could dynamically change the amount of refraction
 
Slereah
Slereah
It's probably not the most efficient lens
Are there fluids where the refractive index varies wildly with pressure?
 
Restioson
Restioson
5:18 PM
oh
And what of air?
 
Slereah
Slereah
Let's find out
 
John Rennie
John Rennie
@Restioson Your eye does a pretty good job of that already by changing the shape of the lens ...
 
Restioson
Restioson
but could you have a canister of air/gas and fill/empty a chamber to allow varied amounts of refraction
 
Slereah
Slereah
 
John Rennie
John Rennie
@Restioson yes you could. I don't know of any cases where this is done, so that suggests that while possible it isn't very useful.
 
Slereah
Slereah
5:21 PM
"should increase by about 0.01% for an increase in pressure of 0.5 atm"
Apparently the formula is $(n^2 - 1) / (n^2 + 2) \propto \rho$
 
John Rennie
John Rennie
@EmilioPisanty re your question about twisted magnetic fields, isn't that basically what a stellerator does?
 
0celo7
0celo7
@JohnRennie Balls!
 
John Rennie
John Rennie
Not now, I have to go out drinking shortly.
 
0celo7
0celo7
you're going to be forever ignorant of them!
 
John Rennie
John Rennie
I will survive the experience.
 
0celo7
0celo7
5:33 PM
@JohnRennie You don't know that
If you drop dead because of the balls, you won't know it
 
John Rennie
John Rennie
Well I suppose I won't survive it, or at least not indefinitely. But right now my focus is on surviving the impending birthday celebrations.
 
0celo7
0celo7
happy birthday?
 
John Rennie
John Rennie
Thanks. I was 56 yesterday.
But deferred the celebrations till tonight on the grounds that checking servers with a hangover isn't much fun :-)
 
0celo7
0celo7
@JohnRennie Does that mean you're 57 today or you turned 56 yesterday?
 
Slereah
Slereah
do u remember the moon landing
 
John Rennie
John Rennie
5:39 PM
Yes, I stayed up to watch it. I was 8 I think.
@0celo7 My birthday was yesterday so I'm now $56\frac{1}{365}$
 
0celo7
0celo7
@JohnRennie If you think mixed fractions are an acceptable form of enumeration, then you might not be cut out for balls.
@JohnRennie that's insane
 
Bernardo Meurer
Bernardo Meurer
Mixed fractions are the cancer of maths
 
0celo7
0celo7
what is an old person doing on an internet forum?
 
Bernardo Meurer
Bernardo Meurer
@JohnRennie Happy birthday man, may many more years come your way :)
 
0celo7
0celo7
@BernardoMeurer hello
 
Bernardo Meurer
Bernardo Meurer
5:42 PM
@0celo7 Darkness my old friend
 
John Rennie
John Rennie
I liked $9\frac{1}{2}$ weeks and that's a mixed fraction
 
0celo7
0celo7
@BernardoMeurer I heard a good Yachty song the other day
 
Bernardo Meurer
Bernardo Meurer
@0celo7 Impossible
 
0celo7
0celo7
Yachty starts two mins in @BernardoMeurer
 
Bernardo Meurer
Bernardo Meurer
Me no likey
 
0celo7
0celo7
5:46 PM
What's wrong with it?
It's 3E8 times better than Minnesota
 
Bernardo Meurer
Bernardo Meurer
Me farting is $10\uparrow\uparrow 10$ times better than Minnesota
 
0celo7
0celo7
Listening to it right now
It's such a strange song
 
Bernardo Meurer
Bernardo Meurer
Lil Uzi is so small
 
0celo7
0celo7
Uzi is pretty tiny
QUAVO
gotta shout that when he comes on
Lil Wayne is small too
 
Bernardo Meurer
Bernardo Meurer
Fucking hate quavo
 
0celo7
0celo7
5:51 PM
that's inappropriate
 
Slereah
Slereah
The meme Lagrangian
 
0celo7
0celo7
memes?
what is $A\cdot F$ supposed to be?
 
Slereah
Slereah
"As fuck"
 
0celo7
0celo7
OH
 
Slereah
Slereah
u may notice that it spells "Dank AF"
 
0celo7
0celo7
5:55 PM
yes
 
Bernardo Meurer
Bernardo Meurer
@0celo7 Kind of in love with this girl right now
 
0celo7
0celo7
Oh no
It's retarded
 
Bernardo Meurer
Bernardo Meurer
I should really stoop messing with my drivers
 
Emilio Pisanty
Emilio Pisanty
@JohnRennie I imagine it does, though already from a tokamak it should be possible
Mostly, I would like a distinct example of a field consistent with Maxwell's equations with a proper proof that the field lines are dense on a surface
 
0celo7
0celo7
@EmilioPisanty It take it the usual dense curves on torus example fails to solve the Maxwell equations?
 
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