The h Bar

Secret

12:05 AM

nature.com/nphys/journal/vaop/ncurrent/full/nphys4244.html

Balarka Sen

12:17 AM

@0ßelö7 DEATH GRIPS IS ONLINE

0ßelö7

@BalarkaSen ?

Balarka Sen

Hah! And you say you're caught up with the memes.

0ßelö7

Not edgy teenager music memes

Balarka Sen

Ꭰeath Ꮹrips

@bbpoltergiest

2.1k tweets, 33.9k followers, following 0 users

dg put up an official tweeter account once again posting "Death Grips Is Online"

and people are creating hundred and thousand memes, writing "Death grips is online" everywhere and they are retweeting and sharing it

0ßelö7

I gathered as much. So?

Balarka Sen

12:21 AM

Well the melon man is excited about it

0ßelö7

Ah, well. I'm too old for that.

You younguns have fun.

skullpatrol

Ok, grand pa :P

...and there's the KICKOFF!!!

0ßelö7

1:47 AM

@ACuriousMind having module troubles again

0ßelö7

3:47 AM

@Slereah ::eye twitch::

38...

0ßelö7

4:43 AM

0

Q: Solving $\Box u=0$ in an open set with $u(p)$ and $\mathrm{grad}\, u(p)$ prescribed

Consider a $C^k$, $k\ge 2$, Lorentzian manifold $(M,g)$ and let $\Box$ be the usual wave operator $\nabla^a\nabla_a$. Given $p\in M$, $s\in\Bbb R,$ and $v\in T_pM$, can we find a neighborhood $U$ of $p$ and $u\in C^k(U)$ such that $\Box u=0$, $u(p)=s$ and $\mathrm{grad}\, u(p)=v$?

John Rennie

@Blue z is of type char so print it using printf("%c", z) or just putchar(c). You are treating it like a string so you're getting whatever happens to follow the variable z in memory.

0ßelö7

@JohnRennie I'm going to sleep but I need you to remind me that I want to use some sort of Cauchy problem to split the derivatives and get the prescribed derivative that way

John Rennie

Will do :-)

0ßelö7

I can compute the spatial part using the initial condition and the time part using the time derivative condition

But then I have to worry about the solution being smooth backwards in time...wonder if I can do that

There's something about time reverse continuation criteria that I have to look up

*for Cauchy problems

Use a Cauchy Kovaleska or Borel Whitney Hormander argument

Idk gotta sleep now

Slereah

6:11 AM

@0ßelö7 Can't escape it

user228700

7:37 AM

Hi, everyone :-)

skullpatrol

Hi pal, wazzup?

:-)

John Rennie

@Kaumudi.H Morning :-)

skullpatrol

(-:

user228700

@JohnR: I have triumphantly escaped my reading slump!!

user228700

@skullpatrol I have just finished reading this book! :-)

user228700

7:42 AM

Also, the chocolate cake that I made yesterday tastes even better today!

John Rennie

Chocolate cake always tastes good :-)

You finished The Sense of an Ending then?

user228700

Yes!

skullpatrol

cool

user228700

It was excellent! I am half tempted to give it another read for I might understand even more of it than I did now but it is quite dense, the book, even though it is only 150 pages long.

user228700

@JohnRennie I am finishing it now and I kid you not, it tastes great, if I say so myself!

John Rennie

7:46 AM

@Kaumudi.H I went a bit mad with eating yesterday. Stem ginger biscuits, chocolate digestive biscuits and two packs of my Mum's fudge. Oh well ... :-)

user228700

::Gasps:: A bit mad?!

user228700

Whatever happened to your plan of eating like this only on the last two days of your stay?

user228700

@skullpatrol And what's up with you? :-)

skullpatrol

Not much, just chillin'

user228700

Hmm, OK :-)

John Rennie

7:55 AM

@Kaumudi.H well yesterday was the third to last day of my stay, so I'm a day ahead of schedule :-) I'll (try and) eat sensibly today. Fish pie for dinner tonight!!

user228700

Haha, nice! :-)

user228700

I'm not any better either, really; I am making the best use of my time with my mum! ...by eating all the food that she cooks, down to the very last morsel.

John Rennie

And a friend of Mum's is coming to dinner tomorrow. We're having Morrocan chicken (basically chicken stew :-)

user228700

Nice! :-)

user228700

And today, I am making Mac. and cheese for dinner again!

John Rennie

7:58 AM

I like macaroni cheese!! :-)

Have you tried adding freshly chopped chilli?

user228700

:-) So do my sisters, father and mum-they all liked it!

user228700

@JohnRennie No! TIPS! Give me 'em!

John Rennie

It's just that while macaroni cheese is nice it can be a little bland. Adding some coarsely chopped fresh chilli gives it a bit of crunch and of course some spicy zing!

For texture you might also consider adding some chick peas.

user228700

spicy zing sounds great! I will do that! While I'm at it, what do you think about adding "freshly chopped tomatoes" to the mix?

user228700

@JohnRennie Ugh! Chick peas in Mac. & Cheese?!

John Rennie

8:04 AM

I find tomatoes tend to go soggy in things like macaroni cheese. And I don't think the tomato flavour works well with a cheese sauce. Just my personal view though.

Bernardo Meurer

@JohnRennie After defeating many beasts of compilation, ProtoBuf version incompatibility defeated me

Which is why I'm moving to Gentoo

John Rennie

@Kaumudi.H for texture. The chick peas add a bit of crunch.

user228700

@JohnRennie Ah, hmm, you're probably objectively right about this one. I won't do that, then...

John Rennie

@BernardoMeurer ProtoBuf?

Bernardo Meurer

Google library

John Rennie

8:06 AM

Ah OK. You have thought that would compile easily. After all it's Google code.

@Kaumudi.H fresh chilli though ... I recommend that.

user228700

Yes! You mean green chilies by "fresh", no?

John Rennie

@Kaumudi.H This is what I use

Those are relatively mild chillis. You don't want to dominate the flavour of the cheese.

user228700

@JohnRennie I was redirected to the home page of Tesco :-/

John Rennie

That's odd, it works here.

user228700

Huh.

user228700

8:12 AM

In any case, right. I don't have access to those red chilies but I do have some of them green ones in my fridge and I will use them!

user228700

When you make it, do you bake it afterward?

John Rennie

I cook the macaroni, then make the cheese sauce. Chop and add the chillis then mix everything together, sprinkle grated cheese on top and put the whole lot under the grill to toast the cheese topping.

So I don't bake it at all.

user228700

@JohnRennie To toast, hmm.

user228700

I dunno the difference b/w toast and bake :-/

John Rennie

Bake is when you put the disk in the oven. Toast is when you put the disk under the grill.

user228700

8:23 AM

Right, but how are the two results achieved different from one another?

John Rennie

Grilling only heats the very top of the dish so you need to cook the macaroni first. You typically only grill for five minutes.

With baking you mix uncooked (or part cooked) macaroni and the sauce and cook it slowly in the oven for 40 minutes or so.

user228700

Ah :-( I wish I had a grill.

user228700

That is the result I wish to achieve but I cook the rest as well.

John Rennie

Physics and the benefits of BREXIT!!

4

@Kaumudi.H Precook the macaroni then put it ina very hot oven for a short time to just crisp the top?

user228700

@JohnRennie Oven, hmm, I have two ovens; one is a microwave oven which cannot bake and another one, which can.

user228700

8:28 AM

OK, I'll see. Thanks! :-)

skullpatrol

TIL the origin of the word "puzzle" is unknown

skullpatrol

8:58 AM

But wait!

archimedes-lab.org/puzzle_etymology.html

John Rennie

etymology: noun: from the Latin "etus" ("eaten"), the root "mal" ("bad"), and "logy" ("study of"). It means "the study of things that are hard to swallow."

skullpatrol

Touché, good sir.

Emilio Pisanty

9:16 AM

oh, btw @JohnRennie, I was reminded of this the other day and I was looking for a brit to make fun of

Tog (unit)

The tog is a measure of thermal resistance of a unit area, also known as thermal insulance. It is commonly used in the textile industry and often seen quoted on, for example, duvets and carpet underlay. The Shirley Institute in Manchester, England developed the tog as an easy-to-follow alternative to the SI unit of m2K/W. The name comes from the informal word "togs" for clothing which itself was probably derived from the word toga, a Roman garment. The basic unit of insulation coefficient is the RSI, (1 m2K/W). 1 tog = 0.1 RSI. There is also a clo clothing unit equivalent to 0.155 RSI or 1.55 tog...

second only to the stone in unit ridiculousness

Stone (unit)

The stone or stone weight (abbreviation: st.) is an English and imperial unit of mass now equal to 14 pounds (6.35029318 kg). England and other Germanic-speaking countries of northern Europe formerly used various standardised "stones" for trade, with their values ranging from about 5 to 40 local pounds (roughly 3 to 15 kg) depending on the location and objects weighed. The United Kingdom's imperial system adopted the wool stone of 14 pounds in 1835. With the advent of metrication, Europe's various "stones" were superseded by or adapted to the kilogram from the mid-19th century on. The stone continues...

skullpatrol

Stones were used a lot for the original boxing weight divisions.

Emilio Pisanty

@skullpatrol Stones are in everyday use in the UK for measuring body weight

the majority of brits I talked with were mostly unable to parse body weights in kilograms

skullpatrol

Interesting, the middleweight division is about 1 stone in size.

13 pounds, actually.

user228700

9:33 AM

@Balarka: This is my immediate to-read list:

user228700

Emilio Pisanty

9:53 AM

Ayn Rand - How Is This Still A Thing?: Last Week Tonight with John Oliver (HBO)

►

=P

ACuriousMind

@0ßelö7 What sort of troubles?

user228700

@EmilioPisanty I've watched that one :-)

user228700

I'm only reading it so that I too can boast of having read it.

Emilio Pisanty

@Kaumudi.H that's.... a weird reason to read a book, but to each their own

Bernardo Meurer

@EmilioPisanty You're a Gentoo user, right?

Emilio Pisanty

9:57 AM

@BernardoMeurer nope

Bernardo Meurer

Were?

Emilio Pisanty

@BernardoMeurer never been

ubuntu since I switched from Windows

Bernardo Meurer

Hmm

I thought someone here used Gentoo

@0ßelö7 Go to bed

Physics Meta

10:30 AM

0

Q: What's wrong with this question?

Can you tell me why this question deserves to be negative? I tried to find faults and I couldn't: I did some research, I did all the calculations I could, and I think it is clear enough . I had deleted it and was going to abandon the site but then I decided to learn what is wrong and see if I ca...

discussion specific-question down-votes

Emilio Pisanty

@PhysicsMeta it's just not very good

Mithrandir24601

@JohnRennie I'm so stealing that :D

Emilio Pisanty

@Mithrandir24601 it's suuuuuper old

Mithrandir24601

10:49 AM

@EmilioPisanty only I quite like the idea of taking that and adding that they were unable to find any immigrants to measure for extra hilarity

skullpatrol

11:04 AM

As opposed to Heisenberg's Immagrant who they are unable to find out how much money they have and where they work at the same time :-)

user228700

11:40 AM

@EmilioPisanty I was only kidding :-) I have heard so many differing opinions on the book that I decided to read it once myself!

Shing

I am a bit confused in classical physics's angular momentum.
For a orbital motion of a point mass: if we pick a new coordinate (that doesn't move w.r.t. the old coordinate), angular momentum should be still conserved, right?
(I calculated a quite absurd result - it is no longer conserved (an additional term that varies with time )

in new coordinnate: $\vec {L'}=\vec{r'} \times \vec{p'}$

$=(\vec{R}+\vec{r}) \times \vec{p}$

$=\vec{R} \times \vec{p} + \vec L$

where the 1st term varies with time. (where R is the shift of coordinate, since R is constant, and p sort of rotating.)

would anyone kind enough to shed some light on this for me?

Slereah

The angular momentum in the new frame is conserved, yes

But only within that frame

Shing

sorry, didn't read it carefully

but d/dt with L' does seem to me not equal to zero, why?

there no additional force, that d/dt L' should really be zero... damn, no idea what's wrong with my calculation.

Slereah

What part is not equal to 0?

Shing

$d/dt (\vec{R} \times \vec p)$

$\vec p$ is (sort of) rotating

Slereah

11:53 AM

If it's a translation, $R$ is constant, hence it will be 0

If it's a galilean transformation, things are a bit more complicated

You need to change both $r$ and $p$

Do so and develop the expression

Shing

thanks! I will try that out

0ßelö7

@BernardoMeurer what?

@Qmechanic Move the question if you want, but I need Valter Moretti to see it. If mods were willing to superping, this would all be much easier.

@ACuriousMind

John Rennie

12:16 PM

@0ßelö7: this is your reminder service:

7 hours ago, by 0ßelö7

@JohnRennie I'm going to sleep but I need you to remind me that I want to use some sort of Cauchy problem to split the derivatives and get the prescribed derivative that way

Balarka Sen

12:29 PM

@Kaumudi Infinite Jest is a big ass postmodern epic

Abcd

Hi @JohnRennie (not possible to tag you in the JEE preparation room, can you come there for a few minutes)

Balarka Sen

I honestly doubt if you'll like that book

user228700

@BalarkaSen I'm not too sure if I will either. I will read it though.

user228700

You seem to have...

Balarka Sen

Not in it's entirety. I got through a nonzero amount but then ran out of time

user228700

12:32 PM

I see.

user228700

Why dyou believe that I won't like it?

Abcd

imgur.com/a/yUnS8

Balarka Sen

From what we discussed, your literary taste seems to be classical/conventional in nature. That book is inherently unconventional in nature; it's not supposed to be read as a novel, it's supposed to be read as an encyclopedia

Abcd

Hey! Could anyone help me with the "think why?" part of the explanation given in the solution? I can't interpret the reason for their having equal velocities.

Balarka Sen

But I'm glad you're trying out various flavors of literature

user228700

12:38 PM

@BalarkaSen Dare I say it, my literary taste continues to change as I have kept on reading :-)

user228700

One book that I finished reading today, The Sense of An Ending (different from the movie with the same title) is far from anything I would've been able to read, even, two years ago, but I absolutely loved it.

Balarka Sen

I see. I have never heard of it.

I've been reading Faulkner's The Sound and the Fury recently. Stylistically very different from anything I have read

user228700

@BalarkaSen Some people seem to love it, as I do, and others hate it with a passion. There doesn't seem to be any middle ground.

user228700

@BalarkaSen Ah, I have heard of that one. ::Googles::

Balarka Sen

Got it. Yeah I have definitely seen that attitude towards a lot of books

Have you read Murakami? Strikes me as something you might like (you're onto mystery thrillers aren't you? Murakami incorporates mystery thriller elements with abstract surrealism)

user228700

12:45 PM

Oh, my God, they did make a movie based on that book! >.< Gosh, who approved that proposal?!

user228700

@BalarkaSen No, I haven't, but I had been meaning to read Norwegian Wood. I haven't gotten the chance yet.

Balarka Sen

You might end up liking it.

user228700

Mystery thrillers, erm, I dunno, not so much, actually.

user228700

How did you get that impression?

Balarka Sen

I dunno, that was just a guess :P

user228700

12:48 PM

:-P Ah.

Balarka Sen

8/10 would reply "yes" to "Do you like mystery thrillers?"

user228700

I used to be in a terrible James Patterson phase many years ago but I am infinitely grateful that it passed!

Balarka Sen

haha

user228700

@BalarkaSen Lol, I s'pose that's true. While I will struggle to put in words what sort of books I like, it's definitely not mystery thrillers! They're alright, but I'm not a fan.

John Rennie

Have you read J. K. Rowling's thriller/whodunnit?

user228700

12:51 PM

Whodunnit. Oh, wow, I had no idea that such a word existed until a few seconds ago!

user228700

And I assume you're referring to The Cuckoo's Calling, in which case, no, I haven't. @JohnR: Why, have you?

user228700

@Balarka: I do not believe that you will answer positively, but I will ask anyway: do you enjoy reading pleasant little haikus? :-P

Balarka Sen

There's not much special place in my heart for haikus unfortunately :P

user228700

Ah, just as I guessed :-)

user228700

I asked because I have just acquired this gem:

John Rennie

12:55 PM

@Kaumudi.H A serialisation of The Cuckoo's Calling has just finished on the UK TV station BBC1. My Mum has been watching it.

Given that you're an HP fan I wondered if you'd read TCC as well.

user228700

@JohnRennie Ohh, I see :-) No, I don't feel like reading it.

Balarka Sen

yeah i saw

user228700

Although, I must say, while we're on the topic of mystery thrillers, that I did like Gone Girl very, very much, in that it sort of blew my mind, the plot.

Balarka Sen

my taste in poetry remains to be in the most verbose lol

user228700

1:00 PM

In that genre, I have read Agatha Christy, lots of trashy novels by James Patterson and a few standalone novels like Gone Girl.

user228700

Please don't come at me for not having read any Sherlock!! ::Ducks, just in case::

Balarka Sen

sherlock is life

sherlock holmes is not really mystery thriller

0ßelö7

@JohnRennie Thanks. Maybe I should hunt down the hyperbolic PDE person at my school

user228700

@BalarkaSen :-o

Balarka Sen

super mathematical detective fiction. i mostly get blown away by the logical deductions than the layers of mysteries

John Rennie

1:02 PM

@Kaumudi.H I'm not a huge fan of the Sherlock Holmes books. They have some charm but they are so dated stylistically.

user228700

@BalarkaSen Ah.

user228700

I will read at least one of them at some point.

Balarka Sen

Agatha Christy is different in style because it's more psychological

user228700

@JohnRennie Ah, hmm, I see :-)

user228700

@BalarkaSen I read Agatha Christy at an age in which I couldn't care about subtexts or anything :-/

John Rennie

1:04 PM

@Kaumudi.H I read all the Inspector Morse books and I quite enjoyed those, and I read some (not all) of the Rebus books and they were OK.

Balarka Sen

Of course, Sherlock Holmes was deeply influenced by Poe's Dupin

and Edgar Allan Poe is my jam

user228700

@BalarkaSen x'D

user228700

I will read some of his works too, at some point. I certainly wish to!

0ßelö7

@BalarkaSen why am I not surprised

user228700

Ah, I'm afraid I must scoot now; gots to buy a few ingredients to make Mac and cheese! Toodles! :-)

Balarka Sen

1:06 PM

0ßelö7

Jesus Christ

John Rennie

@Kaumudi.H Bye. Good eating!

@0ßelö7 you called?

0ßelö7

I called Jesus, not you

@BalarkaSen is there someone in the math room who does hyperbolic PDE?

Balarka Sen

1:22 PM

Not that I know of

0ßelö7

@BalarkaSen there's an old Russian woman at my school who's a famous hyperbolic person

She seems scary

Wonder if I should talk to her

Balarka Sen

lol

0ßelö7

@BalarkaSen she could be like Gromov!

0ßelö7

2:06 PM

@BalarkaSen fug, she's teaching ODE 1 during my break today

Mithrandir24601

2:30 PM

I've just started watching the Fall - it seems good so far (after 1 episode)... I'm with @JohnRennie on the Sherlock Holmes books and would add that the most recent TV episodes were appalling. I've been told to read Agatha Christy but haven't got round to it yet

vzn

3:12 PM

fiction? read this this summer, given to me by friend, nice read, liked it, can relate various ways, recommend it, charles martin :) charlesmartinbooks.com/books/long-way-gone

Balarka Sen

@Mithrandir24601 The TV show is trash

Doyle's work is a masterpiece in deductive detective fiction

Anonymous

@JohnRennie Thanks. I got it now!

Secret

Yup, it's the same guy

?Is it possible to make a time machine ever? Please give an easy answer,a simple one A simple answer, but a possibly wrong one, is to say that a time machine is not possible. Currently, we don't have either the technology to build one, nor a definite, proven (or generally accepted) idea of how we could build one. — Countto10 47 secs ago

Mithrandir24601

3:32 PM

@vzn if it's a romantic novel, which it looks like, it's probably not for me - I'm getting to be more and more fussy about books and have a ridiculously long list to read as it is. I'm going to counter that one by suggesting Ann Leckie's Ancillary Justice series

Although if you like epic fantasy, Malazan book of the Fallen is fantastic

vzn

re zeitgeist/ understanding Brexit/ Trump/ economics influencing politics trends, ran across this recently, recommend it, New Class War by Lind americanaffairsjournal.org/2017/05/new-class-war

Mithrandir24601

I'll stop now, before I fill hbar with lists of novels :P

vzn

@Mithrandir24601 lol it has some love story but its written by a guy so cant be a romantic novel... besides what decent stories dont involve love interests anyway :P ... was just reading his blog, they are gonna do a movie of one of his books with kate winslet, cant beat that right? :P variety.com/2016/film/news/…

Mithrandir24601

@vzn about a third of the description screams 'romance' at me and telling me that they're going to make a film involving Kate Winslet isn't doing much to convince me that it's not a romance :P

vzn

@Mithrandir24601 lol its not the same book cited by me. so youre averse to romance? yikes, that removes wide swathes of "literature"... or maybe not :P o_O

Mithrandir24601

3:50 PM

@vzn "he falls in love with Daley Cross, an angelic voice in need of a song." I think that counts :P It's not that I don't like it, it's just that authors very rarely do anywhere near a decent job of it. If it's a major part of the plot, it's often either eyeroll worthy and cringy or boring and predictable with OK writing. A notable exception is Stephen Erikson

user228700

@JohnRennie It was very good :-)

vzn

@Mithrandir24601 lol, not exactly disagreeing with you, but probably any story you like has some love story component...

John Rennie

@Kaumudi.H how did you cook it in the end?

user228700

Baked it for 10 minutes as you suggested it :-)

John Rennie

@Mithrandir24601 I struggled with the Malazan books, but I really like the Bauchelain & Korbal Broach novellas. If you haven't read them I think they they display a wonderful dark humour.

@Kaumudi.H to crisp up the top?

user228700

4:00 PM

Yep!

John Rennie

Did you add chilli?

user228700

BTW, I am starting to work up some anxiety about returning to college :-(

user228700

@JohnRennie No, but I did add some red chilli powder.

John Rennie

@Kaumudi.H Courage mon brave

@Kaumudi.H that certainly adds some zing!

Mithrandir24601

@vzn depends exactly what you mean by 'love story component', but often yeah... It's not always so bad in sci-fi and fantasy where it's not in the focus so much and just evolves in a reasonable, if predictable way with the storyline, although it depends on what you read (e.g. Brent Weeks, Brandon Sanderson). Of course Patrick Rothfuss completely inverts this trope :) and Lev Grossman is a study on how to do character development and totally destroys typical romance plots

user228700

4:02 PM

@JohnRennie I needed to Google this phrase to find out what it means; thanks :-)

user228700

@JohnRennie It did! I added some pepper as well, although this is quite standard, I believe.

Mithrandir24601

@JohnRennie I'll add them to the list, thanks!

John Rennie

@Mithrandir24601 Someone I know might allegedly have epubs of them :-)

user228700

Allegedly, you understand x'D

John Rennie

@Kaumudi.H You might say that but I couldn't possibly comment

user228700

4:06 PM

@JohnRennie I have a bunch of assignments to submit, most of which I haven't even started and exams too, upon returning!

user228700

(I hope to book a ticket for the train back on Tuesday)

John Rennie

@Kaumudi.H it's traditional to do all the assignments on the last day :-)

user228700

:-) I'm starting tomorrow! Otherwise, my perfectionism will make it near impossible to finish at all!

John Rennie

It seems a bit harsh to have exams so soon after the holiday, but I guess the holiday comes smack in the middle of a term so the college didn't have much choice.

user228700

Oh, no, not smack in the middle at all! My term ends only in December!

user228700

4:09 PM

Oh, how was your lunch?! Fish pie, no?

John Rennie

@Kaumudi.H I guess the ideal thing would be to charge through the assignments in the next two days and have Monday off.

@Kaumudi.H the fish pie was absolutely wonderful. My Mum's fish pie is always good, but this one was nigh on perfect.

user228700

I guess so too :-) I must also prepare for my exams a bit so it's helpful that some of the assignments have me solving problems related to my course.

user228700

@JohnRennie Haha, nice! :-)

John Rennie

Doing the assignments will be a good way to get back into the flow of work.

user228700

Yep, yep!

user228700

4:11 PM

Ooh, BTW:

John Rennie

@Kaumudi.H and I have to confess I have eaten another pack of fudge. Oh well :-)

user228700

@JohnRennie Wow, you really are going for it! :-)

Mithrandir24601

@JohnRennie you're making me salivate over the last fish pie I had :) it was so good :)

John Rennie

@Mithrandir24601 I do like a good fish pie!

user228700

4:17 PM

BTW, @JohnR: Was "Eat like a pig-stay think" a project?

Mithrandir24601

@heather it appears that the CM is looking at the QC proposal. I feel that this is good as it feels like it's getting closer to happening, but bad as some of the questions are now closed...

user228700

I say was because those pictures display exorbitant amounts of food; not unlike the sort of meals you are having now, hmm...so that would make it an ongoing project!

John Rennie

@Kaumudi.H I was curious to see just how much you could eat for around 1,000 calories

And it turns out the answer is quite a lot!

0ßelö7

@Kaumudi.H pls cum n?

Can they not write correctly?

user228700

@0ßelö7 Excuse their terrible spelling :-/

user228700

4:20 PM

@JohnRennie Ah! And this was in 2012, no?

John Rennie

@Kaumudi.H I honestly can't remember.

It kind of became a part of my lifestyle because I try to eat around 1,500 calories a day during the week then go mad at the weekend.

user228700

That is what it says on your Fb page :-) I like to browse through all those pictures of food sometimes, especially since I haven't looked through them all.

user228700

@JohnRennie Right, right :-)

user228700

I'm going to read for a bit before drifting off to sleep. Byebye!

John Rennie

@Kaumudi.H Before you go:

5

Not very good, but the best I could do in five minutes

user228700

4:32 PM

@JohnR: Oh, my goodness...

0ßelö7

@Slereah The idea is to pick some spacelike hypersurface $\Sigma$ containing $p$. Now specifying $u(p)$ is trivial because the wave equation is invariant under constant perturbations. So that's whatever. But I can specify $\nabla u(p)|\Sigma$ by specifying $u(\cdot, 0)$ and differentiate along the surface. For the Cauchy theorems I can also specify $u_t(\cdot,0)$.

Now take the neigborhood to be $\approx (-\epsilon,\epsilon)\times\Sigma$ and then split the metric like $-dt^2+h$

Do forwards and backwards Cauchy solutions, then check that the derivatives match on the interface $\{0\}\times\Sigma$

user228700

@JohnR: Still, that is A+ work for 5 minutes!

Sir Cumference

@JohnRennie Photoshop is man's greatest invention

0ßelö7

@Slereah Now I think that in some Lorentzian tube, the time reverse of a wave equation is a wave equation, so I can get backwards existence theorems.

Anonymous

I'm trying to think of a caption for that picture...:D

user228700

4:39 PM

I am laughing and cringing x'D I didn't think that such a state was possible, even.

Sid

@JohnRennie LOL

Sir Cumference

@Kaumudi.H That's 90% the low quality questions here :P

user228700

Oh, hahaha x'D

Anonymous

'Kaumudi grinning away to glory on her new bike"

Sid

Okay, some help here. Can anyone think of a word with its 4th letter being "S"?

(And somehow even distantly related to USSR?)

ACuriousMind

4:41 PM

@Sid Russia :P

user228700

@Blue x'D That's Gold!

0ßelö7

@ACuriousMind Can you please just ping Valter...

Sid

..Except that. :P

Prathyush Poduval

@Sid Puzzling problem?

ACuriousMind

@0ßelö7 Why would I?

0ßelö7

4:42 PM

@ACuriousMind To help me

Anonymous

@Sid bestwordlist.com/p/s/1/wordsfourthletters.htm

Anonymous

Parse that list

Anonymous

Won't take much time :P

Sid

@PrathyushPoduval Yeah.

Prathyush Poduval

Link?

Sid

4:43 PM

Can't. too much of a spoiler. (I am creating one, you see)

Prathyush Poduval

Oh okay, nice!

Anonymous

@Sid en.wikipedia.org/wiki/Droshky

ACuriousMind

@0ßelö7 That's not what the superping is for.

Sid

(I have what I am looking for now..)

0ßelö7

@ACuriousMind What is it for?

ACuriousMind

4:46 PM

@0ßelö7 Mod stuff

Sid

@PrathyushPoduval If you want a nice one, see this: we were all extremely impressed with this one. puzzling.stackexchange.com/questions/54165/…

Anonymous

Puzzling SE is addictive :P

Sid

@Blue Oh. you have no idea.

John Rennie

@Sid borscht

Sid

@JohnRennie Yep. That was the one I used. :)

John Rennie

5:02 PM

You can rely on me to come with food related answers :-)

Though it has to be said that beetroot is not my favourite vegetable ...

0ßelö7

@ACuriousMind is there a rule against using using mod powers to help children in hurricane zones?

@ACuriousMind is it reasonable to assume that people in an analysis seminar know qm

Prathyush Poduval

5:27 PM

@Sid That really good

Sid

@PrathyushPoduval It is.

@PrathyushPoduval If you are further interested, see the highest-voted questions on the site.

They are awesome

Prathyush Poduval

@Sid Yup, I will...

ACuriousMind

5:56 PM

@0ßelö7 No

skullpatrol

as Feynman once said, nobody really "knows" qm

ACuriousMind

As @DanielSank once said, that's nonsense.

skullpatrol

what does it mean to "know" something?

0ßelö7

@skullpatrol 🤦🏿‍♂️

skullpatrol

6:12 PM

:(

0ßelö7

@ACuriousMind can I spoil GoT yet?

ZeroTheHero

6:58 PM

... wondering if PSE is the appropriate place to discuss this topic:
https://physics.stackexchange.com/questions/356196/would-it-be-safe-to-hide-in-a-stairwell-during-a-hurricane

ACuriousMind

@ZeroTheHero No, questions about human safety could only conceivably be on topic if they are about lab safety.

ZeroTheHero

@ACuriousMind right... we're on the same page.

ACuriousMind

@0ßelö7 I'd prefer you didn't, but I realize at this point it's fully my own fault :P

Phase

Why is it that you can only cool down a substance so far before the energy goes into changing it's state? I assume it has something to do with the distance between molecules meaning that intermolecular interactions have less energy in them than making the distance between them even smaller, but why does it create these bonds instead of making the distance smaller / just reducing the temperature more?

@0ßelö7 really? Edups? D e a d m e m e m a n

CooperCape

@Phase I think one thing to consider is that the molecules slow down allowing them to form instantaneous dipole-induced dipole bonds

Essentially at any point the electron cloud could have a higher electron density say - at the bottom and when molecules are moving slowly past each other this can form partial charges between them

So the dipole has been induced by the other atom attracting them to each otheer

And then the second dipole induces the third etc.

0ßelö7

7:22 PM

@Phase he's alive and well

Sir Cumference

Great, bad sore throat

Getting sick is the last thing I need...

0ßelö7

@BalarkaSen she's scary

Phase

Thanks @CooperCape but this leads me another question I forgot ages ago

If you have an electron cloud, is the electric field from that electron just some sort of averaged field from some centre of amplitude or is it a superposition of fields each coming from some point in the cloud?

CooperCape

I really don't feel qualified to answer that sorry :/

It's a region with a high probability of having electrons

Phase

Yeah

CooperCape

7:32 PM

I'd assume average as the negative charge has a fixed value I think

probably best to check chem.se

maybe this? @Phase

Phase

Assuming that it doesn't cause collapse from the fact that peturbation theory exists with a weak field, im just confused about how you'd actually express the electric field of the electron

?

That doesn't really answer my question as far as I could gather

CooperCape

Apologies...

I can't really help you from this point on

Phase

Oh, well thanks anyway ty