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00:00 - 05:0005:00 - 14:0014:00 - 18:0018:00 - 22:0022:00 - 00:00

user116211
5:42 AM
@0celo7: o/
 
Sir Cumference
Sir Cumference
It's 7:42
no sleep
I think I'm losing it
 
user116211
@SirCumference insomniac?
 
Sir Cumference
Sir Cumference
Yep
pretty sure
 
user116211
@SirCumference You are bound to die by heart attack ;)
 
Sir Cumference
Sir Cumference
screw you man
now i know i wont' get sleep
 
user116211
5:44 AM
@SirCumference Really? If so, take sleeping pills.
 
Sir Cumference
Sir Cumference
i can't
i have an auto-immune problem
 
user116211
@SirCumference Damn
 
Sir Cumference
Sir Cumference
and my doctor says I should stay away from that stuff
well gee, my immune system won't be getting better if i can't sleep
 
user116211
@SirCumference Hmmm.... there must be some sort of anti-caffaine ;/
 
Sir Cumference
Sir Cumference
i looked it up online
best response: try more cocaine
...
 
user116211
5:47 AM
@SirCumference WTF!
 
Sir Cumference
Sir Cumference
ikr
anyway, working on an english assignment and my partner is being obnoxious.
 
user116211
@SirCumference: Just google it; see if there is any means:
 
user116211
 
Sir Cumference
Sir Cumference
she keeps changing all my text into french
 
user116211
I'm seeing many sites are providing means to cure this.
 
user116211
5:49 AM
@SirCumference she is a troll.
 
Sir Cumference
Sir Cumference
i feel like the more i think about sleep, the less i'll get it
@user36790 No, actually, she's obsessed with france for unknown reasons
It's literally the only thing she talks about
it becomes insufferable
 
user116211
@SirCumference Then she is definitely troll.
 
Sir Cumference
Sir Cumference
i know i never want to learn french or go to france
i wish. but she's actually like that
i'm convinced that she is 100% francophile
if that's a word
 
user116211
@SirCumference Talk with her in Klingon ;)
 
Sir Cumference
Sir Cumference
is that from star wars or...?
 
user116211
5:51 AM
@SirCumference Star Trek.
 
Sir Cumference
Sir Cumference
Oh
i don't watch sci-fi.
 
user116211
@SirCumference o.O
 
Sir Cumference
Sir Cumference
What?
I love astronomy, but only real astronomy
I didn't get the references that @0celo7 made about some Jedi stuff
i didn't know science people loved sci-fi so much
 
user116211
@SirCumference Watch Star Wars; first start from 4, 5,6 and then 1,2,3.
 
Sir Cumference
Sir Cumference
but...but...it's not scientifically accurate
i'll be bashing my head over the astronomical innacuracies
 
user116211
5:53 AM
@SirCumference Don't be scien coholic ;/
 
Sir Cumference
Sir Cumference
howdy
it's in my blood
the sciencohol
 
user116211
@SirCumference ha!
 
Sir Cumference
Sir Cumference
on a side note
should i trust what 0celo said about black holes leading to alternate dimensions?
or is it bull?
 
user116211
$$\textrm{Cov(Physics,Sci-fi)}\ne 0\;.$$
 
Sir Cumference
Sir Cumference
Da heck you trying to write?
Oh
I see
 
user116211
5:56 AM
@SirCumference Damn I used textrm thrice!
 
Sir Cumference
Sir Cumference
Unfortunately, I'll never know the joys of sci-fi
@user36790 XD
I never watched things like Back to the Future
 
user116211
@SirCumference nor did I; but I know about it.
 
Sir Cumference
Sir Cumference
Ya know GR, by chance?
 
user116211
@SirCumference Nope; it's beyond my scope till now.
 
Sir Cumference
Sir Cumference
Ay, same
How old are ya
Jesus I'm tired
 
user116211
5:59 AM
I'm an 18yr old high-schooler, just about to get admitted in a college.
 
user116211
@SirCumference Felling drowsy?
 
Sir Cumference
Sir Cumference
Oh cool
17
I wish :D
 
user116211
@SirCumference hA!
 
user116211
@SirCumference: Which country?
 
Sir Cumference
Sir Cumference
U.S.
New York
 
user116211
6:00 AM
@SirCumference oh.
 
Sir Cumference
Sir Cumference
You?
 
user116211
Ind
 
Sir Cumference
Sir Cumference
Oh wow
Far XD
 
user116211
@SirCumference ;)
 
Sir Cumference
Sir Cumference
Dang, you're lucky you don't take the ACT
It's a high school test that colleges care about as much as they do your grades
So...yeah, it sucks
 
user116211
6:02 AM
@SirCumference So, you think we get admitted to college without having any exam?
 
Sir Cumference
Sir Cumference
Er, no?
Well, what do ya take?
 
user116211
@SirCumference Quite a few; but most engineering and architecture- aspiring students take JEE.
 
user116211
There are other exams also.
 
Sir Cumference
Sir Cumference
JEE?
 
user116211
Joint Entrance Examination
Joint Entrance Examination (JEE) is an all India common engineering entrance examination of objective pattern which is conducted for admission in various engineering colleges and courses all over the country. It is regarded internationally as one of the most challenging engineering admission test. In 2012, the government-run Central Board of Secondary Education (CBSE) that earlier conducted the AIEEE, announced this common examination that replaced the AIEEE and IIT-JEE. JEE consists of two parts, JEE Mains and JEE Advanced. JEE-Advanced is for admission to Indian Institutes of Technology (IITs...
 
user116211
6:04 AM
@SirCumference: ^
 
Sir Cumference
Sir Cumference
oh, wow
"It is regarded internationally as one of the most challenging engineering admission test."
o.o
 
user116211
@SirCumference Damn hard.
 
Sir Cumference
Sir Cumference
can't argue with that
oh man, i'm actually starting to fall asleep
at 8:05am...
anyway, 'night
or...'morning
 
user116211
@SirCumference Good night.
 
John Duffield
John Duffield
7:47 AM
@0celo7 : See what? The tumbling light cone? Or the zero-energy universe? Ask a question about it, and I'll explain why it's woo.
@0celo7 : you will learn why there are no wormholes when you understand what clocks do and what time is, and that you don't travel through time, or through spacetime.
 
Slereah
Slereah
Ellis answered me that he had other business to attend to
I don't think we're getting an answer
 
John Duffield
John Duffield
8:22 AM
@Slereah : Will I ever post something that doesn't get downvoted to oblivion? Yeah sure. When you work out that upvotes can't turn horseshit into scientific truth, and vice-versa.
 
 
1 hour later…
yuggib
yuggib
9:33 AM
 
user116211
10:24 AM
@yuggib: o/
 
ACuriousMind
ACuriousMind
10:39 AM
@yuggib Now if I just knew what a quantum random walk was...
 
user54412
Help. I just visited Academia, and once again realized how utterly retarded their userbase is.
 
ACuriousMind
ACuriousMind
Did you read the post where someone argues that ignorance that some act is wrong should mean you don't get punished/don't bear the same consequences as someone who knew for it? :P
 
user54412
I was reading the post where someone pointed out that the OP is a textbook case of the sunk-cost fallacy, only to have everyone in the comments say "no, it can't be the sunk-cost fallacy, because that's what I would do."
 
ACuriousMind
ACuriousMind
Well...the sunk-cost fallacy is notoriously difficult to get people to accept as a fallacy because it's such a basic mode of human reasoning
 
Slereah
Slereah
But @ACuriousMind
 
yuggib
yuggib
10:52 AM
@user36790 o/
 
Slereah
Slereah
I've spent so long believing in the sunken cost fallacy
If I stop now I may never see it used
 
yuggib
yuggib
@ACuriousMind I don't know either, but I feel the obligation to disseminate what it seems to be interesting new physics achievements here ;-)
it seems better than arguing over the same topics over and over again
 
ACuriousMind
ACuriousMind
@Slereah That seems reasonab...dammit!
@yuggib Heh, alright, it's better than finding $\pi$ in the hydrogen atom in any case ;)
 
yuggib
yuggib
@ACuriousMind that goes without doubt
 
0celo7
0celo7
11:31 AM
@ACuriousMind The hell are you trying to say here
@ChrisWhite link?
@ChrisWhite The hell are you trying to say here
 
ACuriousMind
ACuriousMind
@0celo7 It was a post about academic misconduct where the offenders apparently were completely unaware that it was misconduct, and one answer said they should not be punished because they were unaware.
 
0celo7
0celo7
What's up with people not making sense
@Slereah Damn.
 
ACuriousMind
ACuriousMind
Chris' sentence makes perfect sense to me, what's up with you not being able to make sense of it? :P
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Your ability to understand?
;-)
 
0celo7
0celo7
I don't understand the quoted part
 
ACuriousMind
ACuriousMind
11:36 AM
...the entire point is that the quoted part doesn't make sense as an argument.
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
They are acting in a "textbook manner"
 
0celo7
0celo7
It doesn't make sense as English!
 
Slereah
Slereah
@ACuriousMind The hydrogen atom totally has $\pi$ orbitals!
 
ACuriousMind
ACuriousMind
@0celo7 Huh? "No, it can't be X, because it's Y" seems perfectly grammatical to me.
 
0celo7
0celo7
@ACuriousMind huh?
...
 
ACuriousMind
ACuriousMind
11:41 AM
@0celo7 It helps greatly if you elaborate what confuses you :P
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
(r(e(m(o)v)e)d)
 
0celo7
0celo7
@ACuriousMind GR
The proof that the double cover of a spacetime is time orientable
Prop 4.5.10 in HE
Those things confuse me
 
Slereah
Slereah
Because there's always a line element, and if it's not orientable (the vector $V$ gets transported to $-V$), the double cover will have the vector transported to itself?
 
ACuriousMind
ACuriousMind
Apparently, the English language does so, too...
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
All languages are but vehicles...
...and that includes math :P
 
Slereah
Slereah
11:45 AM
How do you say hello in math
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
If
 
ACuriousMind
ACuriousMind
@Slereah "Let x be a greeting. x."
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
If x
 
Slereah
Slereah
If x isn't a well formed formula >:|
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Reformulate it.
 
Slereah
Slereah
11:53 AM
I bought some chocolate waffles
My diet D:
Light dinner tonight~
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Do you guys
use Twitter?
I just started
 
Slereah
Slereah
I had a GR twitter
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
orly?
 
Slereah
Slereah
yeah
GRfact
@GRfact
Your daily dose of general relativity
46 tweets, 0 followers, following 0 users
0 followers, tho :p
 
ACuriousMind
ACuriousMind
Well, you didn't follow anyone else, either
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
12:01 PM
Surprisingly, to me, it has been around for 10 years.
 
Slereah
Slereah
2006 was 10 years ago
2006 was already pretty well advanced into web 2.0
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Right
 
ACuriousMind
ACuriousMind
10 years, and I still don't get Twitter :D
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
:D
 
Slereah
Slereah
Twitter's fine
it's basically for chatting
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
12:03 PM
There's a lot of math and physics news too
 
Slereah
Slereah
What I hate is Facebook
 
ACuriousMind
ACuriousMind
@Slereah I'm not saying it's bad or something - I just don't get it.
 
Slereah
Slereah
I don't want to have my family on the internet
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Facebook is nasty
Too personal
 
Slereah
Slereah
I think as soon as I don't have to worry about finding a job, I will delete most of my personal internet stuff
Delete all the facebooks and linkedin and whatnot
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
12:06 PM
Good plan.
 
Slereah
Slereah
I am ready to be an old man who hates newfangled gadgets
 
ACuriousMind
ACuriousMind
What's your preferred communication protocol, then?
 
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ
math? :P
 
0celo7
0celo7
@Slereah The full proof, not your handwaving
 
Slereah
Slereah
Hm
Hard to say
 
0celo7
0celo7
12:10 PM
And then the proof that a consistent choice of light come allows for a continuous future-pointing vector
 
Slereah
Slereah
There aren't a lot of proof of anything wrt time orientability
 
0celo7
0celo7
Light cone, obviously.
Fucking phone.
 
Slereah
Slereah
Because nobody cares
@0celo7 but that is what a consistent choice of light cone is
a "choice of light cone" is just a timelike vector
 
0celo7
0celo7
Apparently there's a theorem which says if the double cover has a singularity, then the original one does too.
@Slereah You need an intermediary step in the proof
 
Slereah
Slereah
Maybe check that line element paper
Or...
 
0celo7
0celo7
12:12 PM
You actually have to construct the double cover
But it's hard to go from the construction to the vector
 
Slereah
Slereah
I forgot where I got that picture
check up that "Markus"
 
0celo7
0celo7
@Slereah Penrose.
 
Slereah
Slereah
check Markus 13 in Penrose, then
Sounds like a bible verse
 
0celo7
0celo7
$\tilde\gamma_1(1)=[\gamma_1]$ and the other one doesn't make sense
how can one point equal an equivalence class of curves
and the last paragraph doesn't make sense at all
it's essentially 8.1.1 in Wald, which didn't make sense either
 
Slereah
Slereah
mb check Markus then
 
0celo7
0celo7
12:21 PM
wtf is that
 
Slereah
Slereah
I dunno
You have the book
 
0celo7
0celo7
markus?
 
Slereah
Slereah
You know
The one he references
 
0celo7
0celo7
???
 
Slereah
Slereah
Markus , 1955, p. 412
 
0celo7
0celo7
12:23 PM
where is that referenced
 
Slereah
Slereah
First image
 
0celo7
0celo7
what's the full ref
I don't have Penrose
 
Slereah
Slereah
Well neither do I
I'm at work
 
0celo7
0celo7
then how did you get the image
 
Slereah
Slereah
I have it saved in my science folder
 
ACuriousMind
ACuriousMind
12:24 PM
10 mins ago, by Slereah
I forgot where I got that picture
 
0celo7
0celo7
I keep a flash drive with my legal books on me at all times
 
Slereah
Slereah
Don't you have time orientability theorems in your dropbox?
 
ACuriousMind
ACuriousMind
C'mon, that clearly means he already had taken it a while ago.
 
Slereah
Slereah
Just in case
 
0celo7
0celo7
@ACuriousMind I wanted to know how he could access the image
 
ACuriousMind
ACuriousMind
12:26 PM
It's in his dropbox, check the link under the image!
 
0celo7
0celo7
On phone!
 
Slereah
Slereah
you can still click links on phones
 
ACuriousMind
ACuriousMind
Maybe he can't, his Chrome doesn't have JavaScript, after all, imagine what the phone browser must look like
 
0celo7
0celo7
Correct.
 
Slereah
Slereah
You need to step up your game, @0celo7
 
yuggib
yuggib
12:36 PM
 
Slereah
Slereah
I also have that picture in it :
I saved it because there are 4 aligned "isochronous"
 
yuggib
yuggib
string theory divorced from physics almost twenty years ago
so it's not a case of bigamy
 
Slereah
Slereah
and 3 isochronous relativistic space form
 
0celo7
0celo7
Ah, wait
 
DeNiSkA
DeNiSkA
@SMBH123 hello!
 
0celo7
0celo7
12:43 PM
The metric only has one negative eigenvalue
 
Slereah
Slereah
hopefully yes
 
0celo7
0celo7
So we need to show that the vector satisfying $g(X,v)=\lambda h(X,v)$ is unique in direction
the scale is set by $||X||_h=1$
how the f does one show that
 
Slereah
Slereah
If $g(X,v) = \lambda h(X,v)$, then $h(X,v) > 0$ (since it is Riemannian)
 
0celo7
0celo7
Really?
 
Slereah
Slereah
Which means that $g(X,v)$ is always of the sign of $\lambda$
Which means that $X$ has a consistent orientation?
 
0celo7
0celo7
12:48 PM
What about $\delta(\mathbf{i},-\mathbf{i})$
that's $-1$
 
Slereah
Slereah
Are we doing complex spacetimes now
 
0celo7
0celo7
(Euclidean metric on $\mathbb{R}^n$)
the Riemannian metric is not always positive, bro
 
Slereah
Slereah
Well positive or 0
 
0celo7
0celo7
nope
it's linear
how could it always be positive
 
Slereah
Slereah
Isn't it defined to be positive definite
 
0celo7
0celo7
12:50 PM
positive-definite means $g(X,X)>0$
 
Slereah
Slereah
Hm
 
0celo7
0celo7
not $g(X,Y)>0$
 
Slereah
Slereah
I s'ppose
 
0celo7
0celo7
just take Euclidean space
 
Slereah
Slereah
Then I don't know
 
0celo7
0celo7
12:51 PM
I bet ACM knows
That's the same argument but even less clear and with a typo.
 
Slereah
Slereah
IIRC Sanchez actually builds the Lorentz metric from the Riemannian metric and the vector field
p. 4
not quite sure that helps here tho
 
0celo7
0celo7
Yes, HE does that too
As does BLT string theory for some reason, dunno why anymore
Oh I think they argue that the Lorentz metric on a sphere is fucked up
And mb use that to justify Wick rotating?
 
Slereah
Slereah
Everything would be simpler if spacetime was complex to begin with
 
0celo7
0celo7
Oh fuck
@Slereah huh?
 
Slereah
Slereah
Then you can wick rotate all you want!
No need to worry about shit being complex when you don't want it
I suspect that you get causally related point that can't be linked by spacelike curves when you have simply connected globally hyperbolic spacetimes
That way you can't do the spinny lift
Dunno if you can do it with weaker conditions tho
 
skill patrol
skill patrol
1:15 PM
talking about Facebook...
1 hour ago, by Slereah
What I hate is Facebook
 
Slereah
Slereah
Facebook has a really shit interface and worst users
 
skill patrol
skill patrol
yup
 
Physics Meta
Physics Meta
0
Q: How many times has my question been referenced?

John RennieIs there any way to find out how many times a question has been referenced by other questions? Obviously this can be done because when you look at a question you can see linked questions on the right under the heading "Linked", though what I'm after is a simple count rather than a list of questio...

support
 
barrycarter
barrycarter
If I accelerate to 0.8c in 1 second, how much time passes for observers in my starting inertial frame? I compute this number to be fairly low, but need it to be fairly high to resolve a "paradox".
 
Slereah
Slereah
Is the acceleration constant
 
barrycarter
barrycarter
1:30 PM
Yes, in my own frame, so it looks non-constant to inertial frame observers.
(although I'm hoping that doesn't matter... if it does it's going to make things worse)
 
Slereah
Slereah
Rindler coordinates
In relativistic physics, the Rindler coordinate chart is an important and useful coordinate chart representing part of flat spacetime, also called the Minkowski vacuum. The Rindler coordinate system or frame describes a uniformly accelerating frame of reference in Minkowski space. In special relativity, a uniformly accelerating particle undergoes hyperbolic motion. For each such particle a Rindler frame can be chosen in which it is at rest. The Rindler chart is named after Wolfgang Rindler who popularised its use, although it was already "well known" in 1935, according to a paper by Albert Einstein...
^probably what you want
 
barrycarter
barrycarter
I think that's more for long-term acceleration. This is a 1 second "burst" of acceleration and then continuing at a constant speed.
 
Slereah
Slereah
Well you can do Rindler space for that 1 second
 
barrycarter
barrycarter
The "paradox": I start 8 light years from Earth at rest wrt Earth and observe Earth's clock to be t=0.
 
Slereah
Slereah
and then just a basic Lorentz transform for the rest
 
barrycarter
barrycarter
1:37 PM
OK, I hate to ask for "just the answer", but since it's part of a larger problem, I will. If I do accelerate for one second to 0.8c, how much time passes for inertial observers?
When I do the math, it seems like just over one second, but, to resolve a paradox, I need it to be a couple of years.
 
GPhys
GPhys
@FenderLesPaul No, I plan to decide by the end of this week
I have it down to 2 universities
 
barrycarter
barrycarter
Basically, the question is: does the time difference for inertial observers depend on how fast I accelerate, or the just on my final velocity.
 
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