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7:00 AM
Accounting for dark energy, ordinary matter, etc.
 
The curvature is related to the energy density, and that is related to the expansion rate, so in that sense the curvature is related to the expansion. However the pathalogical expansions like big rips are due to weird equations of state and are not necessarily related to the geometry.
You need both the geometry and the equation of state to understand the evolution.
 
@JohnRennie Can you provide an equation relating the curvature with the expansion rate?
 
No.
The Friedmann equations give us equations for $a(t)$ and they include a curvature parameter.
But the curvature parameter is generally put in as one of three values +1, 0 or -1 so the equation doesn't really relate $a$ to the curvature in the way you probably mean.
 
@JohnRennie You're talking about $K$, right?
 
Yes, though we normally use a lower case $k$.
 
7:08 AM
@JohnRennie Notice back up there I discussed it with @ACM
3 hours ago, by ACuriousMind
Sure, $q$ is obviously a function of $w$ and $K$.
He made it clear that $k$ doesn't "control" the deceleration parameter
 
OK
Can you give me some idea of where you're trying to get to. What are you trying to prove?
 
@JohnRennie I was trying to prove that the deceleration parameter is related to the curvature of the universe
Wait what the hell did I just write
2:00am...
 
@Skyler have you had my chili?
 
@DanielSank i have not
 
@Skyler then chili we shall have
 
user228700
7:16 AM
@JohnRennie: I'm sorry, I was having lunch. Just replied to ur mail.
 
anything I can bring that will accompany it well?
 
@Kaumudi got the mail thanks :-) I'll book the delivery now.
 
user228700
@DanielSank Damn, I wish I could have it too. I don't have all the ingredients to make it :'-(
 
user228700
@JohnRennie What's "book the delivery"?
 
@Kaumudi book the delivery = get onto the delivery company web site and order the collection from me and delivery to you.
 
user228700
7:19 AM
Ah, okay. Let me know when they collect it :-D
 
@DanielSank if you have some cornmeal at your place I can bring a few things and whip up a mean cornbread to go with it too
only ingredient im missing at the time
 
@Kaumudi should the name be Ms. Kaumudi. H or with your full surname?
 
user228700
I've been using just H these days so that will do :-)
 
@Skyler I have corn starch, but not corn meal.
 
@DanielSank i actually just saw an interesting cornbread that uses polenta instead of cornmeal, which i have
so i think i can make that work
 
user228700
7:32 AM
@JohnRennie: Is this really happening or am I just dreaming? I'm afraid I'm going to wake up and poof! :-)
 
@Skyler cool
@Skyler chili
 
@Kaumudi I know how you feel :-)
 
shit wait i checked and thats couscous not polenta
whatever, i think i can bring cornbread
 
@Kaumudi Anyhow, it's now booked! I'll mail you tracking info as soon as I have it, then you can watch its progress through the delivery system :-)
 
user228700
That's awesome! I'll obsess about it until it's here :-P Dyou know when it'll be off ur hands?
 
7:35 AM
idk what people even usualyl eat with chilli
 
@Kaumudi Collection from me is today
 
user228700
I see. This is very exciting!!
 
@Skyler I make it with eggs.
Rice if I have it.
 
user228700
Can I ask u some IT stuff related to it here or should I mail u?
 
@Kaumudi @JohnRennie what's all the fuss?
 
7:37 AM
@DanielSank It's a SECRET!!!
 
@Kaumudi everytime i read your name vignette2.wikia.nocookie.net/starwars/images/7/77/…
 
user228700
Aii :-P I've no who that is.
 
user228700
@JohnRennie: I just got an e-mail from the shipping company!!
 
@Kaumudi ki ada mundi
 
Mew
7:40 AM
halo
 
@Mew music started playing in my head
 
Mew
y
 
@Mew quick side question that effects my explanation, how old are you?
 
Mew
@Skyler 80 y?
 
user228700
@Skyler Wow, that's a weird name :-/
 
user228700
7:42 AM
@JohnRennie: Question...s?
 
@Mew theres a very memorable set of songs from a game when I played as a kid around a decade ago
 
@Kaumudi Yes?
 
scratch, 15 years ago
man time flies...
 
user228700
@JohnRennie It's about taking care of a laptop. I can ask here, right?
 
Yes
 
7:44 AM
@Mew and the games name was halo, kinda was fresh in my head
 
Mew
oh yes
my grandson played dat
 
user228700
Okay. Q1: Is it fully charged? Should I like, charge it for awhile after I receive it or is it OK to just start and go?
 
user228700
@Mew x'D Dude.
 
@Mew haha
 
user228700
@Skyler: He's not a grandpa x'D Well, unless he is o.O
 
7:47 AM
@Kaumudi It's fully charged - just press the power button. You'll need to replace the UK plug by an Indian plug (or get an adapter) but there's five or six hours of life in the battery before you'll need to recharge it so you can start playing immediately.
 
user228700
Right, OK, I'll do that.
 
user228700
This is confusing:
 
Mew
jks i'm not really 80
 
@Kaumudi we need to find another grandpa to vet this guy
 
Mew
although you can be forgiven for believing it due to my level of maturity
 
7:48 AM
it was the reaction time
=P
 
user228700
x'D
 
Mew
lol
yeah i'm only 79
 
user228700
 
user228700
I dunno how to use that circular key in the middle and those 3 keys at the bottom, near the touchpad.
 
Mew
oh
that is a mouse pad
the circular key in the middle is to control the mouse
it is an alternative to the touch pad
 
user228700
7:50 AM
What, really? (I'm starting to not trust you, grandpa. You kid too much -___-)
 
Mew
it is like a mini joystick
i'm not joking
 
@Kaumudi The three buttons are mouse buttons. There are two sets of mouse buttons to allow you to use which set you prefer.
 
Mew
That is a mini joystick u use to control the mouse
 
The circular button is indeed a mouse pointer, but no-one ever uses it because it's slow and clumsy. Just use the trackpad.
 
Mew
I used it tho
 
7:52 AM
@Mew grandpas dont count
 
user228700
@JohnRennie Oh, that's weird, OK.
 
Mew
aw
 
user228700
Alright, the ports. I guess I'll ask u about those when it actually gets here but would u recommend one of those...uh, what is it called?
 
@Kaumudi I must admit I've never seen any reason to use the upper set of mouse buttons. I guess they're there for if you're using that circular mouse point thingie.
 
Mew
it could potentially make double clicking faster
 
7:53 AM
@Kaumudi Ports?
 
Mew
I recommend USB
 
user228700
:-P No, hang on.
 
user228700
 
user228700
^ That. Would u recommend getting one of those?
 
user228700
Oh, hang on.
 
user228700
7:56 AM
Nvm, I'm dumb.
 
@Kaumudi No, it already has three USB ports. You shouldn't need to buy anything.
 
user228700
I thought, u know, what if the USB port gets damaged?
 
user228700
But nvm, it was a bad idea.
 
user228700
OK, that's about it. Seriously tho, no other tips?! I suck at taking care of electronic gadgets properly.
 
@Kaumudi No. Just press the power button and start playing ... er ... working hard at your revision I meant :-)
It has everything you need already installed and ready to go.
 
user228700
7:59 AM
:-P Yeah. It would be a relief to type on a proper keyboard again.
 
user228700
Oh oh.
 
user228700
How dyou clean ur keyboard?
 
Mew
not eat on it
 
user228700
:-P Hey @Mew: U have any tips I could use?
 
user228700
(I don't think u guys understand what "I suck" really means)
 
Mew
8:01 AM
don't download dodgy stuff
 
user228700
Dodgy=what?
 
Mew
and get a virus protector
 
user228700
JR has installed AVG for me...
 
Mew
dodgy is like movies etc.
ok cool
 
user228700
@Mew Wut?!
 
Mew
8:02 AM
wat?
oh u mean what is the meaning of the word dodgy?
 
user228700
Then how will I download all of the movies next year?!
 
@Mew @Kaumudi ^^^ that! Type with clean hands and the keyboard will stay clean.
 
user228700
@JohnRennie: You wanna cringe really bad?
 
@Kaumudi I have a 14 year old niece - I'm pretty cringe proof :-)
 
user228700
My mom's old, dead laptop? It has ants. Ants everywhere, inside the keyboard.
 
Mew
8:04 AM
eeewwww
 
user228700
Teeny tiny ones.
 
Mew
yucky
 
user228700
Wow, this is actually a thing.
 
> Of more importance is how to avoid ants deciding to colonise your laptop in the first place. You must have spilled something sweet in there at some point, so you may wish to avoid bringing food and drink anywhere near it.
 
user228700
8:06 AM
@JohnRennie: Don't u combine eating and browsing all the time?
 
user228700
@JohnRennie Yes, right.
 
user228700
No ants in it now, are there? :-P
 
@Kaumudi I do, and even though I'm careful my keyboard does get dirty. But I'm using an external keyboard and they are cheap and easy to replace. Lpatop keyboards aren't as hard to replace as you might think, but they're quite expensive.
 
Mew
@Kaumudi I recommend getting an external mouse
so muhc better
 
user228700
Oh, I see. Okay. Um, that's about it, I guess. I'll ask u about all of the other stuff-if there's anything else-when it gets here!
 
Mew
8:09 AM
and a mouse pad
 
user228700
@Mew Huh, okay.
 
user228700
> "When keys starts sticking, it's time for a cleaning. Shut down the PC. Keep it open as you turn it upside-down and very gently tap on the back so that crumbs fall out. Then use a can of compressed air (you can buy this at any computer store for a few dollars) to blow out whatever is still stuck. Be sure to read the instructions on the can, first. Then turn the PC upside-down and tap it gently again to get the last bits out."
 
user228700
Okay!
 
Mew
why don't u just not eat by it?
 
user228700
Okay :-P
 
user228700
8:11 AM
@JohnRennie: What is the actual price of it?
 
@Kaumudi an external keyboard or a laptop keyboard?
 
user228700
The whole laptop. I've googled and googled but I keep getting very different prices.
 
Mew
@JohnRennie she wants to sell it off
 
user228700
-________-
 
Mew
@Kaumudi given it is second hand and has unique characteristics it's market price is difficult to value
unique characterstics such as line through the screene tc.
 
user228700
8:14 AM
Dood, I am not selling it!
 
Mew
but you could probably sell it on the market for $300-$400 I reckon
 
user228700
I just wanna know.
 
@Kaumudi It hasn't been made for four years, and the original price varied enormously depending on the spec - it came with lots of different processors, memory, disks, etc. So your question doesn't have a useful answer.
 
user228700
Oh, okay...
 
user228700
Okay, those were my very insightful questions :-P
 
user228700
8:16 AM
Thank you :-) I'll tell u when I get it. Take a picture of happy I am and everything and mail it :-P
 
Mew
@JohnRennie do you ever sell the laptops you fix or only give away?
@JohnRennie what version of windows does @Kaumudi laptop have?
 
user228700
Windows 7
 
Mew
cool
the best one
windows 10 isn't bad
windows 8 sucks
windows 7 is great
 
user228700
I see :-) Laterz mew, gots to go study now.
 
Mew
laterz
 
user228700
8:19 AM
Gosh, it's weird, saying "Mew". Who would be named "Mew"?!
 
Mew
don't u know what mew is?
 
user228700
The sound that a cat makes?
 
Mew
it's a fantastic beast
 
user228700
Aw, that looks cute :-) Wokay, bye!
 
Mew
by
 
 
1 hour later…
9:31 AM
0
Q: Problem with shear stress

Prashant More I have a question about my Physics Stack Exchange post: Problem with shear stress A solid shaft in a small hydraulic turbine is 100 mm in diameter and supports an axial compressive load of 140Ï€ kN determine the maximum power that can be developed at 4 Hz without exceeding a maximum shearing ...

 
@JohnRennie JOOOOOHN
I'm up early!
 
Obviously not enough beer! :-)
 
What do I do man, the morning is not something I know
I don't remember the last time I was up before 11:30
 
In my three years as an undergrad I had 9 a.m. lectures every day and in my third years Saturday as well. If you're looking for sympathy then you are seeking in vain :-)
 
Jesus christ that's against human rights
Hell, that's probably even against computer rights
 
9:39 AM
That's the way Cambridge University does it. They work the arse off you. Actually I quite like working that way.
It's very intense, but then if you got to Cambridge you're probably fairly fanatical anyway. I used to get a bit stressed by the end of term, but you had the holidays to recover.
My college bar used to open at 22:30 and close at midnight. So you'd have lectures 9 till 1, then labs 2 til 5, then do a couple of hours problems then drink as much as possible in those 90 minutes. Rinse and repeat :-)
 
I just have classes from noon or 1 PM until about 7PM every day, usually mostly theoretical classes
then we solve some problems until 8-9-ish and go home
Or well, that's what I do
The morning is boring, nothing happpens
I'm going to go play metroid
 
10:17 AM
Hii @JohnRennie
Do you have idea of organic
Chemistry
Do any one else know about organic chemistry
@Mew
 
@koolman You can ask, but I haven't studied organic chemistry for 35 years!
 
Ohk , wait
 
@BernardMeurer fair enough, that's a good working day! It just starts later than mine used to.
 
In the above clainsen condensation reaction
Why the reagent marked does not attack the carbonyl carbon of other compound (given reactant)
 
user228700
Say, @JohnRennie: How many inches is it?
 
10:27 AM
@Kaumudi that's not a question I get asked very often :-)
It's a 14 inch screen. The laptop itself is, err, a bit bigger. It's ll parcelled up now so I can't measure it but I imagine the details will be on the web somewhere.
 
user228700
Geez :-| OK, thanks :-)
 
user228700
Thanks! I was thinking about buying a cover for the keyboard and maybe a case too. Chennai is super dusty.
 
BMVYTY1 is the Dell tag number. The nice thing about Dell's business laptops is you can look them up on Dell's site using the tag and get all the details. There are manuals at:
@Kaumudi You don't need a cover because you can just close the laptop when it isn't in use.
 
user228700
Huh. What are covers for, then? :-P
 
Mew
10:32 AM
@Kaumudi 8 for me
 
@Kaumudi Mainly for when you are carrying it in your bag. You put a cover on the laptop to stop it getting scratched.
@Mew that's a small laptop!
 
Mew
yea
 
user228700
Facepalm
 
@Kaumudi but there's a cover included with it so you don't need to buy a cover.
 
Mew
it's an ipad
 
user228700
10:34 AM
@JohnRennie What?! I thought I'd find ONLY the laptop! You didn't tell me about the cover!
 
Mew
wtf
a free cover
 
user228700
Dude, u're rich. Chill :-P
 
Mew
is it christmas or somtin
 
@Kaumudi this type of cover:
 
user228700
Oh, that's cool!
 
10:36 AM
I had one lying around. I have no idea where it originally came from but it fits so I included it. Those covers are dirt cheap anyway.
 
user228700
Right, OK :-) I think I'll buy this:
 
Study rooms are bloody useless
 
@Mew I suspect that to the extent she's religious at all K will be a Hindu and they don't celebrate Christmas :-)
 
All they do is make me fall in love with random girls and then get over it 5 minutes later for another girl that joins the room
 
user228700
10:38 AM
x'D
 
Mew
@Kaumudi what is ur religion?
 
user228700
@JohnRennie No, we don't :-) @Mew: This is the 2nd time u're asking me that -___-
 
@Kaumudi completely unnecessary - just close the laptop.
 
Mew
yea how am i meant to remember?
oh ur that top tier of 4 hey
is that hindi?
 
user228700
@JohnRennie :-P I'm counting on myself to be clumsy. What if I spill s'thing?
 
user228700
10:39 AM
@Mew HindU
 
Mew
oh sorry
 
user228700
If u're going to forget again, why are u asking again?!
 
@JohnRennie do you have any idea about that question
 
Mew
cos it was relevant to the topic
of christmas
 
I picked the wrong major
 
10:41 AM
@Kaumudi ah, OK, I just checked the details and that's a cover you use while you're typing so the keyboard stays clean. I still think it's a waste of money, and I suspect it will spoil the feel of the typing.
 
user228700
Right. Well, I dunno anything about Christmas other than that some people really hate it and Santa and Christmas tree and presents.
 
CEng is composed of 200 beer-chugging males like me
 
Mew
na people love it here
 
Informatics Engineering is like, only girls
 
Mew
everyone gives presents to everyone
and people slack off
and party
and peopel are kinder to each other
 
10:41 AM
@koolman I'm trying to figure out where the nucleophilic attack occurs. To be honest I don't really know. Did you not get a response in the chemistry chat room?
 
@Mew That's a very utopic depiction of Christmas
 
user228700
@JohnRennie :-/ Maybe...
 
Mew
that's how it is here
they even have parades in shoping malls
 
@Kaumudi Christmas is that time of the year when your fat uncle who works in construction drinks his brains off and passes out next to your grandma in the couch
 
@Kaumudi once you've got the laptop in your hands have a play with it then decide if you really want to buy and gadgets to go with it.
 
Mew
10:42 AM
and decorate eveyting
 
user228700
@BernardMeurer That's Mech. here. There are like 3 girls in a class of 170.
 
@JohnRennie i haven't asked there .
 
user228700
@BernardMeurer Sounds lovely :-P
 
@BernardMeurer trying doing quantum chemistry. No girls at all, and the guys doing it were all nerds and not beer swilling at all.
 
Mew
wtf don't listen to him @Kaumudi
 
10:44 AM
@JohnRennie Bah, I'm going to transfer to Informatics lol
 
user228700
@JohnRennie OK, ::takes advice::
 
Only way I'll ever get myself someone who isn't my neighbour
 
Though when I did my PhD the quantum chemistry grad students were quite a lively bunch and did indeed regularly spend evenings in the pub.
 
@Kaumudi You know I'm right about Christmas
 
Still no girls though
 
user228700
10:45 AM
@Mew No, I have only accepted that different people celebrate Christmas differently :-)
 
@JohnRennie Well, I suppose they couldn't do PhD's back in the 1500's :P
2
::hides::
 
Now I have asked there @JohnRennie . Lets see what reply I get
 
Mew
@BernardMeurer where is ur manenrs
he's still young
 
@BernardMeurer it was really exciting when they invented electricity!
 
Mew
lol
 
10:46 AM
@Mew Where is your grammar?
 
@BernardMeurer asleep next to your uncle :-)
 
Mew
lol John I was about to say dat
 
user228700
x'D The chat is usually dead around this time. This is fun.
 
"Thomas Edison" is just @JohnRennie's alter ego
 
No, I was the guy who flew a kite in a thunderstorm just to see what happened. Now that's commitment :-)
 
10:47 AM
@JohnRennie Weirdly enough my uncle never sleeps, he's just really loud. I do not remember one Christmas when he didn't get me a pair of socks. Including the times he was just back from Europe or the US
 
Mew
@Kaumudi do you have celebratory dates in hindu?
like christmas
 
Though to be fair the doctors who tested drugs by taking them were fairly committed as well. That seems to me to be taking experimental medicine a bit far.
 
Mew
oh she's gone
 
@Mew Devali - @Kaumudi loves Devali :-)
 
Mew
what's that
hindu christmas/
 
10:49 AM
Diwali or Deepavali is the Hindu festival of lights celebrated every year in autumn in the northern hemisphere (spring in southern hemisphere). It is an official holiday in Fiji, Guyana, India, Malaysia, Mauritius, Myanmar, Nepal, Singapore, Sri Lanka, Suriname, and Trinidad and Tobago. One of the major festivals of Hinduism, it spiritually signifies the victory of light over darkness, good over evil, knowledge over ignorance, and hope over despair. Its celebration includes millions of lights shining on housetops, outside doors and windows, around temples and other buildings in the communities...
 
Mew
wow
 
@JohnRennie my fav festival
 
I'll be honest, to me India reached it's highest when they invented the Curry
That, my friends, is a world-changing invention
 
user228700
I don't celebrate Diwali :-P
 
user228700
I celebrate (sort of):
 
user228700
 
Mew
why not diwali?
 
user228700
Thasall.
 
@BernardMeurer and inventing the number zero :-)
 
Mew
did they invent or discover it?
 
user228700
10:55 AM
India has actually done quite a lot but more on that later.
 
@JohnRennie Screw the 0, it breaks division anyway
God bless the curry
@Kaumudi I know it has, I'm just saying at the top of all it has done sits Curry
 
@BernardMeurer Though the number zero doesn't give me a sore bottom the next day.
 
Mew
what about the papadum
 
@JohnRennie Hm? I eat curry frequently, and I never got a sore bottom, at least not because of curry
 
@BernardMeurer you need to eat hotter curries
 
10:58 AM
@JohnRennie Lol, I just eat the cheap one from the nepalese place nearby, it's not too hot
It's bloody delicious though
they make the best curry I've had
 
11:11 AM
Why am I still not sleeping! Argh!
Everytime I start on this website, it never ends. Worst then facebook!
 
@G.Bergeron I was tempted to write a sort of followup answer to your answer:
1
A: If weak force causes decay of a single particle, why is it called a force between two particles?

G. BergeronOn the level of subatomic particles, forces are better understood as possible interaction channels through which states can exchange energy. The analogy with a force "pushing" on something is completely lost, so your second supposition is the right one. The distance you are referring to is about...

 
You no longer are?
 
I would have described the interaction as a transfer of momentum rather than energy, because that provides the link with a classical force (dp/dt)
I also take exception to OP's claim that weak force describes the decay of a single particle - as if that's the only thing it did.
 
I guess transfer of momentum would be better in the case of a scattering experiment... I had in mind transitions in bound states.
Also a good idea to remind him that decay is not the only occurence of the weak force
I didn't want to go deeply into phenomenology as I am no expert in that
Is physics.SE a good place now to ask research questions or is it not quite worth it?
 
11:26 AM
headers: Rc<RefCell<HashMap<String, String>>>
Jesus, this syntax will drive me nuts
 
What is that?
 
@G.Bergeron We have some guys around who are active researchers but there aren't that many of them. We've mostly become a grad level teaching site I think. But I would ask anyway. If you don't get an answer all you've wasted is a few minutes ...
 
@G.Bergeron Rust
 
Still Rusting eh? :-)
 
Yeah :)
Working on that chat server
 
11:28 AM
Have you tried the Rust compiler on Burn? I compiled a Hello World app just to check it worked, but nothing more complicated than that.
 
ouch that syntax hurts my eyes...
 
Allegedly Cargo is built into the Rust implementation I installed.
 
@JohnRennie Isn't that a bit sad?
 
@G.Bergeron there have been several attempts to set up a research level site along the lines of the Math Overflow, but there just isn't enough interest to make it worth while.
 
I need to convince colleagues to come her first then
That's what I was beginning to understand
 
11:31 AM
@JohnRennie I tried some example code I had laying around, also tinkered with Cargo and it all seemed to work :)
 
I don't know why mathematicians like this sort of site while theoretical physicists don't, but for whatever reason that's the case.
Have you looked at the PhysicsOverflow site?
 
It was set up by some disaffected physicists who felt this site was no longer of interest. It's pretty quiet but it may be worth a alook.
 
On the plus side I feel like I know more of physics then I really do when answering questions here :p
 
Can someone step in / comment / edit / moderate here?
-3
Q: Is the Wolowitz-Cooper use of 'interpretation' in quantum mechanics the same as 'interpretation' in probability?

BCLCFrom The Big Bang Theory (The Junior Professor Solution): Sheldon: ...what is the correct interpretation of quantum mechanics? Howard: Since every interpretation gives exactly the same answer to every measurement, they are all equally correct. However, I know you believe in the Many Worl...

I don't want to do a unilateral edit
the question is good - all that's wrong really is the title, I think
 
11:41 AM
...and the structure of the question
 
11:54 AM
Can you edit the title?
I agree it is a surprisingly interesting question but like that, I would have probably passed over it.
 
@G.Bergeron ask away
we need more of those
 

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