The h Bar

Sir Cumference

02:20

@JohnRennie That's why I've seen a lot of advocates for the series definition of pi

Keeps it consistent

But we all know what the true value of pi should be

How Pi was nearly changed to 3.2 - Numberphile

►

Nihar Karve

02:42

Has anyone used any Lp norms in practice (except L1, L2 and sup)

Sir Cumference

02:59

@NiharKarve analysts

but L2 is definitely the most useful to physicists because it's compatible with an inner product

Nihar Karve

03:18

yeah I know, but I'd really like to see, say, an L4 or something used in a physical context

Azmuth

04:43

Lagrangian Invarient const function takes int as input and returns a char array of 4th topological integer as output.

Nihar Karve

04:58

sorry?

Sir Cumference

05:21

@Azmuth what?

123

Hi All

In Linear Air Track experiment. If we use rubber band to apply the force on rider and we release it. Why it produces continuous acceleration? because force is not in contact or by any other means

Physics Meta

06:04

0

Q: Asking for credentials of a user

I saw an answer recently which was very different from all the other answers. It had downvotes but the Author had said someone was deliberately targeting him and downvoting his answers. I looked into his profile and saw multiple such answers which were very debated upon and also some questions wh...

discussion

Azmuth

06:58

Never mind. I was on meds.

123

07:32

Pls answer my question about linear air track.

Charlie

11:46

Anyone been following this rollercoaster of an election night?

Slereah

12:46

I'm afraid bigger disasters loomed over me

I bought some caulk but the nozzle wasn't included

I can't redo the sink's caulk now!

Slereah

13:44

turns out you can use it without a nozzle if you don't care enough

Boy are my hands covered in caulk

JMac

TBH I'm surprised they sell it without a nozzle. All caulking I've see comes in a tube with the nozzle built in.

Slereah

Might have been lost during shelving or something

it is supposed to have one

Nihar Karve

do physicists play video games?

JMac

@NiharKarve No I'm pretty sure they agreed as a group not to do that in 1934. You lose your license to practice physics if you do.

Slereah

Well they do play Kerbal Space Program, from what I can see

ACuriousMind

13:59

I probably spent at least as much time playing video games as a student as I did studying physics :P

Slereah

it is research if there's a physics engine

Monte Carlo method

JMac

@Slereah Even if not, it's still research because you're obviously doing experiments on your mouse/keyboard/controller. That's mechanics and electromagnetism! You're basically cramming regardless.

Slereah

Nilered makes his chemistry videos seem easy

Did you know that if you use an open flame source for distillation and there is too much bubbling, the setup will catch fire

Everyday I learn something new

Dramatization

skillpatrol

TIL

Slereah

I advise you to do the same

Learning with your hand

I also advise to use a heating mantle to heat up chemicals

skillpatrol

14:13

we were taught to use a Bunsen burner

Slereah

I mean if the liquid isn't inflammable, that is fine

Nihar Karve

@Slereah hey, I love NileRed!

Slereah

He certainly has a lot of glassware

Nihar Karve

I think the mercury-aluminium amalgam is what got me hooked

skillpatrol

he seems quite active on social media, also

JMac

14:22

For some reason his videos seem too calming to me and make me tired.

skillpatrol

doing chemistry labs with enthusiasm is a recipe for disaster, no?

ACuriousMind

isn't chemistry all about finding new recipes for disaster?

at least that's what I got from "Things I Won't Work With"

JMac

I thought chemistry was something to do with discovering the philosophers stone? IDK it's been awhile since I read about it.

skillpatrol

14:37

...interesting blog, thanks

Slereah

types question on Chemistry SE I am on fire what to do

Please hurry

skillpatrol

Nihar Karve

15:20

Chemistry? Oh, you mean applied physics.

skillpatrol

that would be chemical physics

or nuclear chemistry

Nihar Karve

@skillpatrol haven't you seen this?

JMac

Hahaha Trump seems to be getting salty on Twitter about the mail-in ballots being counted and ruining his lead that he called a win super early.

skillpatrol

yup, but the real number line isn't descriptive enough @NiharKarve

Nihar Karve

very well, what's the second axis?

skillpatrol

15:30

your imagination :-)

Nihar Karve

purity and popularity maybe

skillpatrol

Chemistry will always hold the popular vote because of biochemistry.

Nihar Karve

You're making some dangerous statements for a physics chat room ;)

skillpatrol

indeed

John Rennie

15:52

Physical chemistry is OK, and theoretical chemistry even better, but organic chemistry is black magic and inorganic chemistry is a form of unusually slow suicide due to heavy metal poisoning.

JMac

That's why I stuck to alchemy.

John Rennie

Someone I knew in the inorganic chem dept at Cambridge was working on complexes of a toxic heavy metal (I forget which) with cyanide. Come to think of it I haven't heard from them for a while.

JMac

I'm still freaked out about the story of that researcher who got some sort of mercury solution on her glove, it soaked through and into her skin, and she basically slowly deteriorated over the next several months or something.

Oh here it is

Karen Wetterhahn

Karen Elizabeth Wetterhahn (October 16, 1948 – June 8, 1997) was an American professor of chemistry at Dartmouth College, New Hampshire who specialized in toxic metal exposure. She died of mercury poisoning at the age of 48 due to accidental exposure to the organic mercury compound dimethylmercury (Hg(CH3)2). Protective gloves in use at the time of the incident provided insufficient protection, and exposure to only a few drops of the chemical absorbed through the gloves proved to be fatal after less than a year. == Career == Wetterhahn was born in Plattsburgh, New York, and had degrees from St...

Nihar Karve

@JMac how's the transmutation going?

JMac

There's a lot of fumes and glowing, so I'm clearly onto something.

John Rennie

15:57

What are you transmuting into?

JMac

I'm still figuring out how to do it! I'll figure out how to control it later geez guys don't rush me.

skillpatrol

@JohnRennie and to think that the "black magic" of organic chemistry are the theoretical foundations of biochemistry

JMac

Once I turn platinum into gold I'll be rich though!

Nihar Karve

@JMac you beat me to it by 3 seconds!

BioPhysicist

@Charlie I went to bed around 10:30 Central time.

JMac

16:05

@BioPhysicist Were you expecting it to be close like this? I feel pretty surprised as a Canadian; but after 2016 I kinda tempered myself to expect anything.

BioPhysicist

Yeah, I figured it would be close.

Trump certainly wasn't going to win by a landslide, so the only options were a close victory on either side, or Biden with a landslide. But since 2016 was so close despite polls I figured it would happen the same way this time.

Nihar Karve

Anybody actually from the US here? A lot of us are just spectating currently

BioPhysicist

I am

JMac

I'm honestly more surprised that the polling managed to somehow screw up worse than last time. I figured it would be pretty off based on last election, but it seems like they really dropped the ball again, possibly worse than last time.

Nihar Karve

was 538 reasonable?

John Rennie

16:08

@JMac if a pollster asked you if you were going to vote for Trump, would you admit it?

BioPhysicist

I haven't been digging through the polls too much... but I don't think a lot of them said this was impossible. I think it was still within margin of error closer to last night

oof haha

Yeah, a lot of people are probably scared to admit voting for Trump

although if it is to a random pollster then maybe it wouldn't matter?

JMac

@JohnRennie No, and I get that it was one of the big reasons not to expect too much from the polls. But after 2016 I would have expected more correcting for that, and it somehow seemed like they went further in the wrong direction. AFAIK we don't even really talk much about "early polling" here, so maybe it's all just foreign to me.

John Rennie

Trump is such a larger than life figure that we tend to see only him, and not the fact that lots of Americans agree with his policies regardless of what they think of him personally.

Nihar Karve

honestly though, reminds me why blockchain voting is such a bad idea

BioPhysicist

Yes, that

John

skillpatrol

16:10

^

ACuriousMind

@JMac Interesting you'd say that, the "sunday question" asking people who they'd vote for (named so because elections are always on a Sunday) is a constant part of political reporting here in Germany, not only in times of actual elections

BioPhysicist

Well it's still pretty close here right now. If you went based on leads right now then Biden would win, but if Trump manages to pull ahead in just one of the states Biden is leading in right now then Trump wins.

JMac

Interesting. There's definitely some idea on which way things will lean before elections here, but I don't see it reported in terms of like expected numbers and early polling like I saw so much in the states.

BioPhysicist

And those states are all pretty close...

John Rennie

@ACuriousMind By and large European politicians behave like sensible human beings. Though I suppose there was Berlusconi ...

JMac

16:19

One thing is that a lot of votes left are mail-in AFAIK, and Trump was kinda anti-mail-in; but at this point I wouldn't be surprised if that didn't actually change much and a lot of mail-ins are still Trump.

ACuriousMind

@JohnRennie I was commenting on JMac saying they don't pay a lot attention to polls in Canada, not on the "admitting to vote for Trump" part :P

John Rennie

Ah :-)

skillpatrol

lol

Are you allowed to admit you don't vote?

ACuriousMind

sure

BioPhysicist

Lol you aren't forced to go and vote

ACuriousMind

16:24

there are countries with mandatory voting

skillpatrol

^

BioPhysicist

Sorry, I thought we were still talking about admitting for voting for Trump

haha

JMac

I heard first time in Australia you get like a $20 fine or something; eventually leading to them taking away your right to vote for awhile for repeated non-voting or something seemingly nonsensical like that.

Nihar Karve

can't wait to vote

BioPhysicist

Wait if you repeatedly didn't vote then why would a punishment be to take away your right to vote?

Your punishment is to keep on doing what you have been doing!

ACuriousMind

16:28

I really can't decide whether that makes a lot of sense or no sense at all

JMac

Yeah that's the part I found nonsensical. I think I saw it on like a John Oliver clip making fun of it or something?

BioPhysicist

Reverse psychology

JMac

And yeah, it's like kinda illogical, but kinda makes sense, like we might as well just give up and make it so we don't have to deal with it since you clearly don't want to.

Nihar Karve

but they could just make it not compulsory?

JMac

But they want to encourage people to vote usually. Whether or not that is a good thing is pretty subjective and complicated; but that's usually the goal of compulsory voting.

Nihar Karve

16:32

just ramp up the fines, taxes go brrr

I kid

ACuriousMind

Given how (counterintuitively) effective tactics seem to be that involve just telling people days before the election to actually go and vote, compulsory voting may have a point

JMac

@ACuriousMind Depends on if it actually benefits your side to have more people voting :P

skillpatrol

Forced voting is not freedom.

ACuriousMind

as long as you're still allowed to just make your ballot invalid it doesn't take away the ability to express dissatisfaction with the process as a whole and you get a better idea of which "non-voters" are just lazy vs. actually don't want to vote for anyone. Also makes voter suppression harder since if you fine people for not-voting one would hope you also take more care of making it actually possible to vote

BioPhysicist

"This year voting is only open for those who support candidate X"

JMac

16:36

@BioPhysicist That's basically North Korea elections afaik. It's both mandatory, and with only a single candidate; to ensure that the leader always has full support.

BioPhysicist

Classic North Korea

JMac

That's a country that knows how to get on the same page! /s

Nihar Karve

"a voter may cross off the candidate's name to vote against them, but must do so by crossing out the name without secrecy" - wow

skillpatrol

nvm

BioPhysicist

I know ACM is dying to get back into the free will debate :P

ACuriousMind

16:41

I want to but I will not

geocalc33

A conformal compactification is an embedding of a non-compact Lorentzian manifold into a compact Lorentzian manifold as a dense open subspace, such that the embedding is a conformal map.

I don't understand why, for example in a Penrose diagram the lines intersect!

because my book says that a "cross" is not a "topological manifold" at the crossing point because it's not locally euclidean

ACuriousMind

You'll have to be a bit more precise what lines you mean and why you think they shouldn't intersect for someone to answer that

geocalc33

and there are all these "crosses" in a Penrose diagram, where lines of const. time and lines of const. space cross eachother

ACuriousMind

but in any case the two manifolds in a Penrose diagram are the interior of the square (the non-compact spacetime) and the square with its boundary (the compact manifold in which the non-compact interior is embedded)

what's being embedded here is the entire spacetime = interior of the square, not some individual lines

geocalc33

oh thank you

John Rennie

16:51

Lithobrake into low altitude synchronous orbit — shay 11 hours ago

2

That just made me literally made me laugh out loud.

ACuriousMind

it's a time-tested technique for stopping!

geocalc33

@ACuriousMind been struggling with that for a while. thanks. guess I was reading the book by it's cover

BioPhysicist

I guess I don't know enough to know why that is funny :(

geocalc33

and are the lines of const. time and space in any compactification of $\Bbb M^{1,1}$ necessarily compactified hyperbola

BioPhysicist

Or is the joke that if you are on the surface then you are in a low altitude synchronous orbit?

ACuriousMind

16:54

@BioPhysicist Yes, it's an exaggeratedly euphemistic way of saying "Crash into the surface rocks"

John Rennie

Which does indeed decelerate you to a halt, and you end up moving synchronously with the Earth's rotation, though I think it is a stretch to call the resulting crater an orbit.

BioPhysicist

I mean if all you knew was the position as a function of time...

Nihar Karve

17:20

You guys haven't met in person, have you?

John Rennie

Emilio and I once came within 50 miles of each other. I think that's as close as I've been to meeting anyone who chats here.

Nihar Karve

In any case, I'd just like to say how cool this community is

ACuriousMind

this silence is probably the collective panic as everyone tries to figure out whether to react to that compliment :P

Nihar Karve

I was wondering :D

ACuriousMind

I mean, any single person saying something like "Thanks" would sound a bit weird but no one saying anything is awkward, too

skullpatrol

17:32

the awkward silence?

John Rennie

My niece once told me I was cool, but that was just after I'd given her a laptop.

Nihar Karve

@JohnRennie you'll always be cool to all of us

John Rennie

:-)

(John immediately proves he is not cool by using an emoticon instead of an emoji)

Nihar Karve

I too have a niece

But she's older than me

Charlie

Emoticons are way better than emojis for the record, I always go out of my way to stop them appearing in messages I send to people

Especially when sites replace a single ":)" with a huge awkward ugly smiling emoji. ugh

Nihar Karve

17:36

I think my heart rate stabilises if I receive an emoticon from an unknown user on chat

@Charlie Microsoft Teams is the worst when it comes to that

Positively grotesque smiley

Charlie

There was a period where the Facebook ones were ok, but they updated them at some point and now I hate them too

skullpatrol

gifs are the way to go for me

Charlie

yeah gifs are good

skullpatrol

tastefully done, of course

ACuriousMind

@NiharKarve I still haven't figured out how to reliably distinguish ;) and :) there

Nihar Karve

17:42

How is that pronounced?

GIF?

skullpatrol

yup

ACuriousMind

gif is pronounced gif, obviously

Nihar Karve

@ACuriousMind I dunno, the :) is more dead-eyed

Its unnerving

I think I've started the slow descent into madness where I just have to play all YouTube videos at 2x speed

Sir Cumference

@JohnRennie emoticons >>> emojis :P

@Charlie man i hate that, even discord has that issue

BioPhysicist

@NiharKarve I think I live close by to @rob

It’s pronounced GIF.

►

skullpatrol

17:53

gift minus t = gif

Nihar Karve

Good ol' Tom Scott

Jacques Bailly, rather disappointingly, says G-I-F

skullpatrol

what does a negative t sound like?

Nihar Karve

But GIF with a hard G makes sense considering it stands for graphics

BioPhysicist

That video makes a case against that argument lol

e.g. you don't hear "JPEG" as "J-FEG"

Nihar Karve

Why would it be J-FEG?

BioPhysicist

17:59

P for photographic or something like that

Nihar Karve

Oh yeah

skullpatrol

JPhEG

Nihar Karve

I personally say jif

Call me sacrilegious if you will

BioPhysicist

The video has other examples. The point being that acronym pronunciation does not have to match with how the letter in the acronym is pronounced in the word it is used in

skullpatrol

jiffy peanut butter

BioPhysicist

18:01

I switch between both. Although I rarely ever have to speak it

You all still use sound to communicate? I only talk to people through the internet / texting

I don't remember what my wife sounds like anymore

Nihar Karve

Wait, really?

BioPhysicist

I only hear her when she laughs at a gif I sent her

ACuriousMind

the old people I work with don't know how to chat so I have to yell at them over voice chat (or "phone" as they call it) like some sort of savage

skullpatrol

savage

BioPhysicist

Oh you use phones as phones? That is quite odd

Nihar Karve

18:04

The phone is a conduit to the Internet

A means to an end

JMac

I guess I just worked a boomer job because we used phone calls all the time :(

But then you need to confirm everything in email anyways...

BioPhysicist

I mean once we can upload our consciousness to the cloud then why would we even need to speak?

On a related note, the show "Upload" is pretty good

Nihar Karve

Is the Social Network at all what it's cracked up to be?

skullpatrol

@BioPhysicist i'm not going to no cloud because i'm afraid of heights, pal

BioPhysicist

Well they can't call it going "to the ground"; that is already taken

skullpatrol

18:09

going underground?

BioPhysicist

= dead

skullpatrol

into the ether

or wind

dust in the wind

Nihar Karve

"uploaded to the ether"

Has a ring to it

skullpatrol

> Now don't hang on
> Nothin' last forever but the earth and sky
> It slips away
> And all your money won't another minute buy

uploaded as dust into the ether wind

schn

22:29

What is it that, when an object rotates really fast, distorts its shape? Like

en.m.wikipedia.org/wiki/Haumea

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