« first day (2963 days earlier)   

1:16 AM
Heh, seems like you can get the "Still Fresh" hat just using the association bonus
 
Thinking about what kind of set can model the behaviour of bosons:
1. You can pile as many bosons as you like in the same state, until the energy density become so high that it becomes a black hole
Don't recall sets in set theory have this cutoff property
 
 
1 hour later…
2:24 AM
OK. Why has no one posted today's xkcd yet???
Both arXiv and archive.org are invaluable projects which, if they didn't exist, we would dismiss as obviously ridiculous and unworkable.
2
 
3:02 AM
@Blue yeah, it's pretty cool
the prof i'm collaborating with had a good laugh when I wrote down 553664 as the number of vertices :P
 
 
1 hour later…
4:06 AM
Has anyone every heard of “Dirac observables”? It seems related to Quantum Gravity, about which I know very little.
 
4:56 AM
I dont know why this question is still closed, even after being edited
-1
Q: Doubt regarding expression of angular momentum

NishantTwo thin circular disc of mass $m$ and $4m$, having radii of $a$ and $2a$, respectively are rigidly fixed by a massless, rigid rod of length $l = \sqrt {24}$ a through their centers. This assembly is laid on a firm and flat surface, and set rolling without slipping on the surface so that angular...

Pretty obvious question regarding the doubt of the angular momentum.
 
5:20 AM
@AjayMishra Hmm, that's the angular momentum question from JEE 2016 :P
They'll find the answer if they search the net well. C.f. this
That aside, when asking such questions you need to boil it down to a single concept
There's excessive numerical detail in the first paragraph (it's better to generalize the problem using variables $M_1, M_2$, $a_1, a_2$ and so on)
And too less research effort shown
I appreciate the effort you put in to edit that question though (the initial version was absolutely terrible)
But it requires a bit more work (like giving it a more searchable & descriptive title, showing some research, etc)
Nevertheless, keep in mind that PSE does not intend to be a physics "help" site. It's supposed to be a reservoir of high quality, "easily-searchable" Q&A
Imagine: someone else, who doesn't know about the JEE, is stuck with a similar angular momentum problem, in the future. If they type in "two disc system + angular momentum" on google, they'll most probably not land up on that thread
It's our collective duty to transform the problems into more generalized ones so that it can be of help to a larger set of people
2
 
5:39 AM
I think, it is doubt regarding the definition of the angular momentum, like overcounting the same rigid body
There is literally nothing involved in there, it was basic definition question, so I thought it would be great if someone has trouble getting the idea with sine component of position vector of mass element, and distance from the axises might get help.
 
@AjayMishra As I said, we are not a physics "help" site. There's a separate chat room for that. Encouraging such poorly researched questions would only be a downhill ride for us.
 
I agree one would get solution from the books and internet, and I think the person who asked the question did so, that why he had the doubt regarding the expression of angular momentum.
indeed.
 
> I think the person who asked the question did so
Then they'd have to clearly express what they did and what exactly they found while doing so
In its current form it lacks research effort + is too localized + lacks a good title
Once that's fixed, I think you can ask people to reopen it
 
@Blue may be or may not be
okay.
 
In my personal opinion, it's next to impossible for a site to accommodate high quality research-level or grad-level physics questions alongside these undergrad/high-school level physics problems. If we have to encourage the former it's absolutely necessary to keep a high bar for the latter. Or else we'll just end up becoming another Quora.
Imagine a professional physicist landing up on the main page of the site and noticing such JEE type problems all around. They're sure to go - 'tis not the place for serious physics, and leave the site for good (I half-believe that's already happening :/). Add to that the terrible question formattings.
 
 
2 hours later…
7:24 AM
@Blue I mean that's kind of the reason Physics Overflow exists
 
@SirCumference Physics Overflow is dead
 
Oh, didn't know
 
It's in the ventilation now with recycled questions from Physics SE which hardly anyone ever answers there
 
Well you could bring it up on meta. There used to be a theoretical physics SE that got merged with this. Perhaps it's worth considering another one of those
 
I'd love a Theoretical Physics SE now
But I don't know if SE has sufficient manpower to get that to private beta
Physics SE already doesn't have much experts around
So I don't know if such a site will survive without external sponsorship
The easier alternative is to ban homework and undergrad level questions from PSE and bam - you have a site for experts
But that's probably not gonna happen....because reasons
The middle ground is to keep a high bar for pre-grad level questions
 
7:31 AM
Well we do have MathOverflow and Theoretical CS surviving as distinct sites from Math and CS (although MO does predate Math.SE) Regardless I think there ought to be a place for lower level questions and expert ones, just not necessarily the same SE
I probably wouldn't have gotten into physics if I didn't find low level answers to some questions I had
 
Well, one could always try to propose a new site on Area 51. But whether it will survive the Area 51 stage is something we'll have to wait and see
 
I still think it definitely warrants a meta post first
 
I think such a proposal has already been made twice now, and been rejected by the SE guys
So unless we can convince them, it's going nowhere
@SirCumference Sure
Anyhow, making a new expert site isn't gonna automatically improve the question quality on the existing Physics SE
Question level is a different thing from question quality
I don't have problems with the former, but I do have issues with the latter
Discussions related to newbie questions can still be excellent and insightful provided the OP puts in sufficient effort
You see there we have - MO and Math SE (one is an expert site). But still there's a huge controversy regarding PSQs (students posting homework questions without showing much effort and people still answering them) there, on Math SE
Nevetheless, this particular discussion is always frustrating. Most of gave up on the hw problem issue on PSE and MSE, long ago.
 
8:09 AM
On a different note, I've been trying to eat fishes (with tons of fish bones) with spoon and no hands - it's fun and I'm getting better at it everyday :P
 
8:34 AM
@Blue Math.SE hasnt become Quora.
 
@Abcd It's on the path there
 
@Blue as if.
 
You may disagree.
Anyway, if all you took from my huge essay is "Math SE is turning into Quora"...there's some miscommunication.
What I meant there was mostly metaphorical rather than literal
 
Whoa
We have a main site
We have a meta site
Why don't we have a hw site
Chemistry already has a homework issue
Math & physics as well
 
8:54 AM
@AvnishKabaj In short, SE isn't gonna support a separate homework site. That has been debated ad nauseam, and been shot down by them every single time
Some Physics SE people previously made a separate site for hw. I think some of you are aware of it.
 
Quandaphysics?
 
@AvnishKabaj Yes
 
Homework questions do keep the site thriving
 
@AvnishKabaj But there's only one guy who answers questions there
It's a desert
 
Well you could use researchgate
@Blue where ?
 
8:58 AM
To keep such a site running and healthy you need more people
 
@Blue and only 3-4 people visit there
 
@AvnishKabaj qanda
 
Physics Q&A
Sammy gerbil answers
And 3-4 people like koolman ask
Sometimes I ask too if no one is around :p
 
What's the link?
It's qanda
Oh
 
8:59 AM
Oh they have changed the name @Blue
 
@AvnishKabaj Research gate is not for students
@Abcd No, I think it's accessible from both links
 
@Blue cant find other one
 
@Blue but isn't that what you wanted?
Only theoretical questions?
 
@AvnishKabaj Well, I wanted something like Math Overflow rather than Research Gate. Also on Research Gate you can't stay anonymous
 
@Blue area 51
You won't be able to change pse
 
9:02 AM
And honestly, the Stack Exchange UI is way better than RG
@AvnishKabaj Yeah, I'm not hoping to :P
 
Hands down
@Blue whaaaaaa
Then what's the point of all this debating whatnot
 
@AvnishKabaj There wasn't a point as such
Was just putting forth my views and observations about the site
 
Also someone asked why their question isn't being opened
 
9:04 AM
So that was an explanation of our philosophy
 
That's the reason
 
 
6 hours later…
rob
2:53 PM
On the subject of homework-like questions (he said to an empty room): I had to spend about five solid hours this week explaining to my ten-year-old the difference between his arithmetic class, which he hates and struggles with, and mathematics, which he finds amusing and is good at.
I read him the "musician's nightmare" section of Lockhart's Lament, without reading him the title of the essay, and he recognized immediately which academic subject was being parodied.
I also used that essay's examples of real math questions as ways to get him to experience the "oh! aha!" sensation of actually understanding something interesting about the way that logic works, and told him that that's what mathematics is like.
Since I've been helping him with long division, I've stumbled on a question about the repeating decimal expansions of fractions with prime denominators. I was able to explain that question to him, and to talk about how I might go about looking for an answer, but that I hadn't yet. And he got that, and agreed that the question was interesting.
And I pointed out that, even though he's having a hard time dealing with his arithmetic class, he knew enough long division to appreciate this thing that I was asking. I told him that long division is like an alphabet that he needed to be able to have the conversation with me.
And long division, like the alphabet, is stupid and boring. Nobody talks about the alphabet as an interesting object with students who are older than about age eight. Instead, you use the stupid and boring alphabet to read clever and interesting books about dinosaurs --- or literally anything else.
 

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