The h Bar

12:09 AM

time to discover a new law of nature i suppose

2:16 AM

@bolbteppa we discussed this at length previously. fields are apparently different resonances in the fluid. the resonances can be nearly independent, or sometimes interacting. fields are an apparently fractal "scale invariant" property of the fluid. fields are propagated via fluid (density) waves and possibly density variations. current physics does not seem to imagine that the same fluid could give rise to multiple (scale varying) fields as an emergent property.

Novalium Company

5:56 AM

Guys, what do you think the economic damage of the coronavirus will be on the world? Do you think the coronavirus opens up new opportunities for new businesses?

I mean, people will get poor but then things will start to get better and some businesses will have failed and that would require new ones, do you think the economic damage of the coronavirus opens up new opportunities for entrepreneurs?

skullpatrol

Obviously, mask sales have gone up :P

Secret

6:34 AM

I would love to see the current economy crumble to dust and then replaced by a new system

skullpatrol

a New World Order?

Loong

8:18 AM

@NovaliumCompany Since this is a Physics site, let’s have a look at a few numbers.

For example VW:

For this year, they had a planned revenue of 257.77 billion and a planned EbitDa of 38.32 billion.

So, we can estimate the costs at 219.45 billion.

Assuming they stop everything but the costs stay the same (they actually don’t), they can afford to wait for roughly 2 months before the numbers become red.

Since they also should have 20.33 billion in cash left in their pocket from last year, they could afford to wait another month.

morning

huomenta

@Loong Finnish?

yes

8:36 AM

@JohnRennie Do you know Finnish or did you use Google translate (like me)? :-)

John Rennie

Google translate :-)

As I recall Finnish is a weird language. It's not one of the common language groups.

Guru Vishnu

kunnossa

Hope it was properly translated :-)

John Rennie

@GuruVishnu :-)

Slereah

@JohnRennie What is the "common" language group :p

Sino-tibetan?

So I have looked into the whole "Spacetime continuum" issue

Apparently this is due to some debate in the nature of the real number line and other associated objects in th early 20th century

And one of its big investigator was Herman Weyl!

Who did not appreciate the Dedekind construction of the real numbers

Loong

Proto-Indo-European language

Proto-Indo-European (PIE) is the linguistic reconstruction of the ancient common ancestor of the Indo-European languages, the most widely spoken language family in the world. Far more work has gone into reconstructing PIE than any other proto-language, and it is by far the best understood of all proto-languages of its age. The vast majority of linguistic work during the 19th century was devoted to the reconstruction of PIE or its daughter proto-languages (such as Proto-Germanic and Proto-Indo-Iranian), and most of the modern techniques of linguistic reconstruction (such as the comparative method...

Slereah

8:43 AM

Hence the weird appearance of the ~continuum~ in pop science

@Loong Nobody has spoken PIE in 8000 years

Not very common at all!

Loong

hm

ACuriousMind

@Slereah PIE is still very common! I hear ApplePIE is an American favourite...

skullpatrol

not to mention PIE day :P

John Rennie

I would guess most of we nerdy types find this whole "origin of language" discussion absolutely fascinating, but I have to wonder about the proposed PIE vocabularies I've seen. It seems to be stretching things a bit if not a lot.

PM 2Ring

Finnish is in the Finno-Ugric family. So is Hungarian. One Python RO is Finnish and another is Hungarian, and they occasionally compare & contrast their mother tongues.

Loong

8:53 AM

I talk to dogs in Finnish because I never had a dog before and then I learned the usual dog commands in Finland.

Slereah

@JohnRennie Well by its very nature it's a bit speculative

ACuriousMind

@JohnRennie Reconstruction of a dead language that has no direct relicts is by its nature a guessing game, and the reconstructed words should not be taken as "this is how all PIE speakers talked" but more like "given what we know about the regular changes that happened in the descendant languages, assuming this PIE word existed explains words with the same meaning as cognates in the descendants".

Slereah

If you want to look at the power of reconstruction, there are a few papers which are like

reconstruction of latin from modern languages

Then you can see the difference between the reconstruction and the real language

Loong

@ACuriousMind big bang theory for linguists

John Rennie

@ACuriousMind I don't mean to be critical. If being a language scholar were my thing I'd be right in there figuring out what the PIE for random access memory was.

ACuriousMind

8:55 AM

But of course this isn't proof that the words really are cognates and that the PIE word existed. The best you can do is reconstruct a PIE word from one subset of languages, then predict the corresponding word in a descendant you didn't use for the reconstruction. If you get a number of hits, you can be pretty confident in your reconstruction

Sometimes the PIE word seems far-fetched because the chain of regular language changes over thousands of years has changed almost every sound in it in the descendant

But as long as these changes are regular, and not made up to explain that particular word, it doesn't matter how far the original word seems from the modern one

John Rennie

IIRC you have an interest in languages? Didn't you learn ancient Greek for fun?

Slereah

Of course it's hard because most of the languages involved are dead and never wrote anything down :p

ACuriousMind

@JohnRennie Yep :)

Slereah

The language record for IE languages only goes back to about 2000 BCE, and even then only for a few languages

skullpatrol

For fun?!

Guru Vishnu

8:58 AM

ACM αυτό είναι υπέροχο

Slereah

Sanskrit, hittite, mynoan greek, etc

ACuriousMind

Well, not entirely for fun because we had to choose an elective - the alternatives were French, some weird mixture of politics and how to use a computer and biology/physics.

skullpatrol

ok

John Rennie

My niece did ancient Greek GCSE, again mostly for fun, but then she's always been weird :-)

(She was planning to do Classics at university but then chose Archaeology instead)

skullpatrol

Whelp, the language we think in is important, imo.

Slereah

9:01 AM

Mynoan greek is the worst language for archeology because it is almost 100% paperwork about flax

John Rennie

:-)))) Now there's a legacy.

ACuriousMind

Most of the fun for me was not in the language itself, but in reading texts from thousands of years ago in the original. You know, in English class we mostly read boring contemporary stuff, newspaper articles, essays on politics, or a strangely uninteresting selection of fiction. In Ancient Greek we quickly started reading the Odyssey, Platon, or a weird satire about Charon and Hermes making fun of humans.

Slereah

Ancient greek has plenty of fun texts, but that's a fairly recent thing

skullpatrol

It makes a nice complement to Latin also.

Slereah

Writing before the iron age was almost entirely religious texts and paperwork

My favorite thing about Mynoan greek is that we know from archeological records that only about 60 people in the entire history actually ever wrote anything

Then the Bronze Age Collapse happened

And then they all died

PM 2Ring

9:08 AM

Speaking of ancient languages, I think it's pretty cool that we have several centuries of systematic astronomical observations from the Babylonians. Western astronomy inherited some of that data via the Alexandrian astronomers. Of course, some of that knowledge was temporarily lost in the West during the Dark Ages, but IIRC, the Babylonian methods for predicting the phases of the Moon & eclipses were preserved during those times.

Slereah

Beheaded by various revolts and wars

John Rennie

Maybe they got coronavirus.

Slereah

And then Greece completely forgot about writing for 700 years

PM 2Ring

Some of that Babylonian stuff (translated into English) is available online, but I must admit that it's not exactly exciting to read. ;)

Slereah

Also there's a lot of lies about it

Like how the Babylonians knew the pythagorean theorem

When in fact they just had tables of Pythagorean triples

And no proof of the theorem anywhere

It was probably a ad-hoc formula

also guess who finally found that paper on Filippov Differential Inclusions

www2.eecs.berkeley.edu/Pubs/TechRpts/1986/ERL-86-5.pdf

woo

Guru Vishnu

9:46 AM

How to access pre-formatted comments like the one below for homework type questions? :

Please note that homework-like questions and check-my-work questions are generally considered off-topic here. We intend our questions to be potentially useful to a broader set of users than just the one asking, and prefer conceptual questions over those just asking for a specific computation. — ACuriousMind ♦ Jul 16 '19 at 20:52

PM 2Ring

@Slereah Fair enough. It seems like they knew how to construct Pythagorean triples though, they (probably) didn't just do a brute force search. There's discussion about that at en.wikipedia.org/wiki/Plimpton_322 but I've only briefly skimmed that article.

Slereah

@PM2Ring We do know that some formulas were ad-hoc, though

Because some of them were wrong

tpg2114

12

Q: A place for helpful comment templates?

I often find the need to have a comment template saved for future use, say when indicating to an asker that they need to write equations in MathJax instead of attaching them as images (with links to relevant meta threads on using MathJax), or trying to get them to improve a question asked with th...

Slereah

ie the formula for the volume of a cone

Or the estimation of $\pi$

tpg2114

Looks like the comments listed in the answer may not be up to date for what ACM currently uses, but you'll see how it is done

Or maybe they are current and I haven't had enough coffee yet.

Guru Vishnu

9:50 AM

tpg2114 Thanks! Why aren't they enabled as default when I flag a post as hw type?

like we do in low-quality posts review...

ACuriousMind

@GuruVishnu Because it's not a functionality provided by SE - the auto comments are a userscript someone wrote on their own.

Guru Vishnu

ACM Thanks for the info.

PM 2Ring

@Slereah True, the early mathematicians didn't really get into providing proofs. That didn't really happen until the Alexandrians. And even then, they weren't very rigorous. For that matter, even by Euler's time, proofs could be pretty sloppy. :)

Novalium Company

@Loong Okay let me rephrase my question, is it a good idea for someone to start a product company now (or after a few months)?

PM 2Ring

One of the great strengths of the Western mathematical tradition is its notion of proofs. Mathematicians in other cultures didn't really get into it, to the same degree. Roughly a century ago, Hardy brought Ramanujan to England. He was impressed with Ramanujan's results, but he found it difficult to make Ramanujan understand why it was necessary to prove stuff rigorously.

John Rennie

10:02 AM

Ramanujan was obviously a physicist really.

PM 2Ring

:D

skillpatrol

The Man Who Knew Infinity showed him as relying on inspirational dreams...

John Rennie

Speaking as an (ex) industrial physical chemist, physical chemists are less rigorous than physicists, and industrial physical chemists are less rigorous than academic physical chemists. For most of my career if it worked once that was good enough :-)

PM 2Ring

@skillpatrol Yep. I read the book, but haven't seen the movie. Inspiration from dreams is fine, but then you have to back it up with rational proof.

skillpatrol

The movie was worth re-watching at least twice, imo

Novalium Company

10:08 AM

Omg there are people online. Coronavirus doing something good for this community finally

skillpatrol

his defiance of being forced to learn Hardy's rational proof methods was awesome, not to mention the racism he fought; all dramatized for the big screen of course

Novalium Company

"The Man Who Knew Infinity" ahhh no.

If he knows infinity then I know my 12th grade grades.

skillpatrol

worth watching, nonetheless

PM 2Ring

10:33 AM

@NovaliumCompany The sentiment of that title is that Ramanujan had a strong sense of personal connection with mathematics. That is, he knew Infinity like a personal friend. From en.wikipedia.org/wiki/Srinivasa_Ramanujan

Hardy quoted Littlewood as saying, "Every positive integer was one of [Ramanujan's] personal friends."

Novalium Company

So he didn't have many friends so he made math his friends?

And he imagined that infinity existed next to him in some type of physical form?

and maybe talked to it

and it maybe answered back

skillpatrol

yup

Novalium Company

@PM2Ring "had a strong sense of personal connection with mathematics" what does that mean?

like, he didn't "take it to the next level" with maths right?

ok i'm done making fun of this person but srsly, seems like bs to me

I'm sure he was a great mathematician but to claim that you "know infinity"...

I think I should just watch the movie

skillpatrol

he went from extreme poverty to studying in Cambridge

Novalium Company

@skillpatrol that doesn't make you "know infinity"

John Rennie

10:38 AM

@NovaliumCompany number theory is a branch of mathematics where we get relationships that seem bizarre when you first see them.

PM 2Ring

@NovaliumCompany He didn't make that claim. Other people did. Here's another quote from Wiki:

A deeply religious Hindu, Ramanujan credited his substantial mathematical capacities to divinity, and said the mathematical knowledge he displayed was revealed to him by his family goddess. "An equation for me has no meaning," he once said, "unless it expresses a thought of God."

John Rennie

Experienced number theorists begin to get a feel for what relationships are true and why, but Ramanujan seemed to have an extraordinary ability at this.

Novalium Company

Technically, you can't "know" infinity because whatever you imagine, infinity will be one above that. So to know infinity you must not know it. So I know infinity.

ACuriousMind

A classic: God spoke "$\nabla \cdot B = 0$, $\nabla \cdot E = \rho$" and there was light.

Novalium Company

@PM2Ring Oh the poor guy. The guy just wanted to study maths and people turned him into some type of magical person with "relationships" with maths...

skillpatrol

10:42 AM

4 mins ago, by Novalium Company

I think I should just watch the movie

:-)

Novalium Company

will do in the evening, gonna pop some popcorn and gonna learn a bit more about this individual

John Rennie

@ACuriousMind surely God would have used a covariant formulation? :-)

Novalium Company

He seems like a cool guy tho, I'm sure he'd love a game of Fortnite

ACuriousMind

@JohnRennie I certainly believe so, but sadly $\mathrm{d}F = 0, \mathrm{d}{\star}F = j$ isn't so instantly recognizable to most :P

Novalium Company

skribbl.io/?16i3aQbJ0ELA

Come play skribbl.io with me

John Rennie

10:45 AM

@NovaliumCompany Who? God?

Novalium Company

@JohnRennie the maths guy

Ramanujan

John Rennie

@NovaliumCompany God is currently playing a new video game called Coronavirus.

skillpatrol

@ACuriousMind A classic response: It did not last: the Devil howling "Ho! Let Einstein be!

ACuriousMind

what

skillpatrol

actually a reply to Newton :-)

Novalium Company

10:48 AM

@JohnRennie good one

What would you tell Ramanujan if he was secretly alive and reading this chat right now?

(btw no one joined my skribbl.io game, thanks guyz)

ACuriousMind

@NovaliumCompany "Stay at home"

@NovaliumCompany I'm still working even if I'm lurking around here :P

John Rennie

@ACuriousMind from Nature: Pope also wrote in his Epitaph for Sir Isaac Newton (perhaps anticipating the need for this journal?): Nature, and Nature's laws lay hid in night God said, Let Newton be! and all was light. to which J. C. Squire (1884–1958) in his Epigrams replied: It did not last: the Devil howling “Ho! Let Einstein be!”, restored the status quo.

Novalium Company

@ACuriousMind u programmed right?

skillpatrol

sniped again

ACuriousMind

@JohnRennie ...but that line makes no sense as a response to my version w/ Maxwell's equations since they're Einsteinian, not Newtonian to begin with :P

@NovaliumCompany Yes.

Novalium Company

10:53 AM

@ACuriousMind I started doing some freelancing stuff a week ago. I'm making some cash with which I'll kickstart my product company.

(JohnRennie plz don't reveal anything about the product)

skillpatrol

I read Einstein had a picture of Maxwell in his office in Princeton

PM 2Ring

@NovaliumCompany He was a humble guy, but he knew he was good with numbers. Back in the day, his mathematical ability amazed a lot of people, and the fact that he was divinely inspired, and came from the mysterious East added to the mystique. He was great, but not infallible.

Novalium Company

@PM2Ring Did he do anything good for humanity? What is his legacy? Knowing stuff doesn't bring value to anyone.

PM 2Ring

@NovaliumCompany Large numbers of mathematicians since then have developed stuff that Ramanujan started. And of course he has been an inspiration to generations of Indian mathematicians & scientists. He worked in pure mathematics, so there aren't a lot of direct practical applications of his work. However, a lot of stuff that was pure maths a century ago (like a lot of stuff about prime numbers) now does have practical applications in stuff like cryptography.

Novalium Company

yay, cryptography

so he was an inspiration, like an indian celeb

i'm inspired to become an influencer

like the instagram ones you know

and I'll advertise stuff and i'll get money

and i'll be rich and i'll buy a lambo

(every girl in my class in a nutshell)

skillpatrol

11:03 AM

gold diggers?

Novalium Company

meh

don't really care about em

30 days off and I don't have to see a single face, the dream of an introvert

PM 2Ring

Eg, Ramanujan graphs in cryptography

Novalium Company

soundcloud.com/user-599486398/somebeat/s-vFSZn

listen to my little beat

i'm bored

Aaron Stevens

12:31 PM

Yes, @R_4127 you're correct. If an object is pushed around and ends up in the same place with the same velocity, then the work done is zero. This is because Δx is zero. If the object has the same position and velocity, then the potential and kinetic energy it had before and after the movement is the same - hence no work as been done on it. How it travelled between the beginning and end has no relevance. Remember though, this is Physics, not the real world. In Physics there is no friction or air resistance, which is why the work being zero is unintuitive. — David Reidy 57 mins ago

Ugh...

Guru Vishnu

> Remember though, this is Physics, not the real world.

I wish I were able to downvote that comment.

JMac

@AaronStevens Yikes. It's the last two sentences that really get me there. Like geez, I don't know how you misinterpret the purpose of physics like that. It's like he's convinced that all physics is the approximations they teach you when you first start learning the basics.

Aaron Stevens

12:53 PM

@JMac I guess. Yeah that part threw me off. Usually you would see something like "this is mathematics, not the real world".

Are we allowed to flag comments like that as "no longer needed"?

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