The h Bar - 2019-09-21 (page 2 of 2)

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6:00 PM

@WhitePrime GR is so successful there has been no classical advance on it in 100 years, why is that a bad thing

@WhitePrime It took the smartest brains our species has ever produced thousands of years to come up with our modern understanding of physics. Correctly modeling the universe is hard.

There has been plenty of advances in GR

you just don't really hear about them

nobody cares about perturbative stability

@WhitePrime You're being hostile yourself by just making unfounded assertions denigrating physics. So don't be surprised if I push back.

Gravitational wave

Gravitational waves are disturbances in the curvature of spacetime, generated by accelerated masses, that propagate as waves outward from their source at the speed of light. They were proposed by Henri Poincaré in 1905 and subsequently predicted in 1916 by Albert Einstein on the basis of his general theory of relativity. Gravitational waves transport energy as gravitational radiation, a form of radiant energy similar to electromagnetic radiation. Newton's law of universal gravitation, part of classical mechanics, does not provide for their existence, since that law is predicated on the assumption...

Regarding GR waves: "Newton's law of universal gravitation, part of classical mechanics, does not provide for their existence, since that law is predicated on the assumption that physical interactions propagate instantaneously (at infinite speed) – showing one of the ways the methods of classical physics are unable to explain phenomena associated with relativity." syncing up with my above comments

@ACuriousMind Fair, fair.

6:05 PM

@RyanUnger Was this an Alicia Keys joke? :P

You can do anything you want at Alice's restaurant

6:22 PM

@ACuriousMind yes

@Slereah lots of people care

1/4 of my department does classical GR

@RyanUnger name 5

@RyanUnger Tell them to hire me

you don't know any PDE

$f_xf_y = 0$

There's one

math.princeton.edu/events/…

Argh PDEs is important for GR?

6:24 PM

Well for all of physics

why does it feel like every math is used in it

GR is literally a theory about PDEs

@Slereah well like high level PDE stuff

Basically every math is in GR

Except number theory, maybe

@SirCumference I mean high level PDE stuff is in most of physics, rly

physicists don't really do physics properly so you don't see it

6:26 PM

@Slereah I feel like your pic is closer and closer to the truth

Jan 25 at 10:33, by Slereah

user image

>descriptive set theory

whoever wrote that is a moron

@RyanUnger it's literally just a list of almost every math topic

I think the worst math I've ever seen in GR is modal logic

Like I did not expect it

but it's not too far off from the title :P

@RyanUnger I see Zorn's lemma quite a lot in GR

Well

I've seen it twice, at least

6:27 PM

Zorn's lemma is first class in undergrad

that doesn't count as anything

sigh

i wish i could just learn all the math before i learn the physics

Gödel may disapprove of this endeavour

If you want to do physics mostly get a lot of analysis and linear algebra

That covers a lot of what you really need

i mean algebra in general is useful

mostly from what i hear about QFT

you don't really need any math to do physics the way physicists do it

it's all just by the seat of your pants bullshit

@RyanUnger i'm thinking of being a mathematical physicist

6:30 PM

dude even then

everything becomes way more beautiful when you understand the math behind it

lots of those guys don't know what they're talking about

Phew, I managed to update to newer drivers without having apt uninstall the rest of my system this time

@RyanUnger I mean also, my whole reason for learning physics is because I want to understand how the universe works, to the best of my ability

The math makes it way more clear why we care about certain concepts in physics

just be a mathematician

6:32 PM

no

I don't understand why anyone would be a mathematical physicist

i want to understand how the universe works :P

it's math with errors

bah I understand how the universe works but I'm a mathematician

@RyanUnger It combines the beauty of math with the wackiness of the universe

why would you devote your life to stuff with errors

physics just isn't a good field

it's OK to know about but you're doing a disservice with your intelligence

6:33 PM

@RyanUnger Ah come on, that's a vague assertion :P

most math was also bullshit until like

the 19th century

and even then it took a while

and now it isn't

@RyanUnger the physicists would argue why would you devote yourself to stuff you'd never plan to apply :P

It must take a very specific mind to find maths beautiful.

I never plan to apply any of the physics I do

I recoil at the idea of practical applications

6:35 PM

@WhitePrime You get to that point when you manage to make unintuitive statements in mathematics intuitive

Things become clear and you get this rush, like it's a massive achievement

I kinda want to chase that

ur fucking with me right

I see.

physicists don't apply their stuff

@RyanUnger Physics is to math what (most) math is to set theory/logic

that's a fair point but set theory is legitimately boring

math is not boring as you said

6:37 PM

Set theory is beautiful dammit

How do you not find the foundations of mathematics fascinating

That's literally the most fundamental things ever

good for the people who do that

it doesn't matter to me

@RyanUnger every theorem you prove in math uses certain axioms

don't you care why we chose those specific axioms to be true?

the axioms make sense to me

I never use ZFC so idk what that's about

naive set theory is fine

I mean yeah they make sense, but people have to decide which should be considered truth

The rest of math depends on that

it's not always clear which should be defined as truth and which shouldn't. there was a big resistance against accepting AC for a while iirc

AC is definitely false

6:41 PM

ok you see that's my point

choosing the correct axioms, which isn't something that everyone can agree upon, has a massive impact on the rest of math

set theory/logic really aren't as isolated from everything else as they seem to be

Is it an unpopular opinion to say Stephen Hawking was wildly overrated?

that's not unpopular, it's stupid

6:57 PM

@RyanUnger I bet now the set theorists are gonna say you lack rigor

Mathematicians don't do anything properly!

that's fine

they're marginal figures

@RyanUnger do you think the negation of the axiom of choice is true

nope

sup

do you deny the excluded middle theorem axiom, @RyanUnger

7:00 PM

I'm undecided

Well you'd better deny it because otherwise you're just gonna get either the axiom of choice or its negation

Or you could just deny any larger set than $\mathbb{N}$ I suppose

And just do finitist set theory

I read Princeton is dropping the GRE for a lot of grad programs @RyanUnger did you write it?

@RyanUnger Interesting opinion.

~~stupid~~ silly

:)

@WhitePrime While I think wildly overrated is extreme, I certainly know some people who will acknowledge his scientific output was uneven. As I wish my output was as uneven as his, I will myself refrain from being critical.

@skullpetrol would you have a link to this Princeton+GRE item?

7:20 PM

princeton.edu/news/2019/09/17/…

that^ is a huge change to the standardized testing movement @ZeroTheHero

I wonder what’s the demand (in terms of #of applications) for these programs compared with others at Princeton.

Quoting from the linked article: “Studies suggest that GRE scores are not great indicators of graduate school success and underserve students who cannot afford test prep or taking the exam multiple times.”

probably a partial reaction to the recent wave of college entrance exam scandals

7:39 PM

I wonder if this will open the floodgates in terms of # of applications.

I think that's what they're hoping for.

(according to the link)

poor admissions committees

for grad school that's professors

did you write it?

7:56 PM

yeah

oh

8:22 PM

I guess that happened the year you were gone.

(I didn't mean to bring back any bad memories :)

2 hours later…

10:37 PM

guys, honest question

user image

am I the only one to leave this type of notes on rough work?

I generally don't insult myself in my notes, no :P

danielunderwood

I often comment on how stupid something I tried was

Or code comments of how terrible a solution is and how I'll fix it later

11:21 PM

honest answer: no, you're not the only one; but I'd use something a bit more constructive than "daft" :-)

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