New model for dark energy is bascically thr balloon analogy made literal

hope this time you have a good way to test for extra macroscopic dimensions

Meanwhile nature released yet another new trailer for its upcoming blockbuster movie on nuclear physics and yet we still have no idea what that movie is ever since the first trailer back in 2014

hI

When I am hungry, I don't read well.

Seriously, from neutron slipping into mirror sector, to that Hungarian physicist proton decay particle, to superfluid QGP, to proton neutron pairing etc. When are you going to release that blockbuster, nature?

don't tell me it's a vapourware. We have had enough when Valve turned half life 3 into vapourware

@vzn paradigm shift seemed to be on delay

Akash: So many teasers on New Physics, yet not even a single sign of it

@Secret hmm

hi every one

Also anyone who tried to do quantum woo with Taoism, they will fail because the two concepts are incompatible: Taoism stripulates that everything has a predetermined way of evolving that people cannot see, whereas quantum mechanics said all microscopic physics are probabilistic and there are no local hidden variables

Hi all, practical question

I was on math SE and asked about a problem with polylogarithms

They sent me here since they didn't want to bother with it and the integrals of polylogs are more common in physics

I've typed up a question for the main site here on physics SE, but the math tags now suggest to instead ask the question on math SE

So basically I'm being sent back and forth

So I'm confused now where I should ask/put my question

Hi everyone, I have a question about aerodynamics

@Dat I'm no expert but I am an enthousiast (being a bike rider). What's your question?

I often read that when dealing with incompressible flow (either invisid or viscous flow), the continuity and momentum equations are sufficient. Does that mean energy equation is abundant?

But when I try to manipulate energy equation with incompressible assumption, I can't get the same momentum equation

I'm not qualified to answer it, but it does sound like it's worth asking a question to find the answers you seek

As in, posting it as a question on the main page

thank you for suggestion

Sachs and Wu has the worst notation

It's like they decided that physics conventions were for chumps

Akash: Ok screw what I said previously. Tao is neither deterministic nor indeterministic. Really have to stop using analytic philosophy to view Taoism

@Dat Yes

But what do you mean by abundant?

Do you mean sufficient?

Sorry, redundant*

It's mathematically redundant because you're solving for four unknowns: pressure and velocity, with four equations: continuity and momentum equations

@GodotMisogi Lets talk here

yes

I don't see how Determinism ⇒ No free will, and No free will ⇒ Nihilism is true

@GodotMisogi I'll put it simply:....If determinism is true then whatever choice you think you are making isn't actually,really a choice making...its just what the set of laws that govern the universe make you do.......so no free will....and nihilism is true

My bad, I forgot determinism's definition invokes the idea of no free will, so the second implication is redundant. The implication should be Determinism ⇒ Nihilism is true. If the definition of nihilism is "life is meaningless", then I don't see what free will has to do with it.

@GodotMisogi It's just the way I relate free will actually......what exactly is life without free will?

Determinism is true, free will is an incoherent concept, nihilism is only true if you decide it is, and I'm terribly hungover

I was typing what @ACuriousMind just said, including the hungover bit

@GodotMisogi Ohk...but that wasn't really our topic right.....You asked me how free will implies nihilism and I asked you what is life without free will....@ACuriousMind answer doesnt answer my question right!

Although I'd put it as "Determinism is observably true", since it's not...determinable...if the vaguely defined "consciousness/free will" affects the laws of the physical world as we know or model it

@ayc I can't answer your question because I don't think "free will" is a well-defined concept. In what observable way does a world without free will differ from a world with free will?

@GodotMisogi what is it here?.....could you explain what you just said in a simpler way....I dont really understand it

@ACuriousMind No observable difference....But world without free will just doesn't add meaning to life

I don't think unobservable things should determine my outlook on life :)

Finally, some metaphysics

For me, I had dreams before where I get to experience what it is like to have no freewill: It is like you thought there is freewill, but you then realise everything including what you think is predetermined and scripted. It is actually pretty scary

@ACuriousMind By observable difference I meant that both worlds will just proceed!.....But the world with free will will proceed in unpredicatble way...giving meaning to life as there is choice making.....In the worl without free will everyhting happens in a definite way......so no choice making really...and hence no meaning to life.......I believe we are in a world without free will ...and this fact should influence the way you see life

even though how you will be influenced or whether you will be influenced or not ..is predetremined

@GodotMisogi your answer really helped me. I have another question about Navier Stoke equations. Look at these equations :grc.nasa.gov/www/k-12/airplane/nseqs.html. I am more familliar with Navier Stoke equations that are exactly the same with these but not include 1/Re and 1/Pr numbers. I understand the derivation of Navier Stoke equation without 1/Re and 1/Pr numbers. How come equations from NASA site have Re vaf Pr numbers ?

@ayc So free will is equivalent to randomness (=world proceeding in unpredicable ways) in your opinion?

(Also, are all those '.....' really necessary? :P)

@Dat Ah yes, non-dimensionalisation, the cornerstone of fluid mechanics.

@GodotMisogi I think its the other way around. If I recall analytic philosophy correctly, ontology is a branch of metaphysics, whereas metaphysics covers a host of other things besides ontology

@ACuriousMind Yes,but remmebr that,that world is hypothetical to me...

I don't see how a world in which random things happen is more meaningful than a world that is predetermined, I have to say

And, again, I don't see how you could really tell the difference. Everything that you think is "random" could have a deterministic explanation (hidden variable theories!) which you have not yet found.

@Dat The main reason for using these non-dimensional numbers (look up their definitions) is because they form a good set of parameters to compare fluids of different viscosities, densities, thermal conductivities, etc.

@GodotMisogi 1.Choice making.....2.choice making,nothing other than that .....3. chat.stackexchange.com/transcript/message/48232534#48232534

@ACuriousMind Worse, there could be physical rules which is beyond our biological brain's capability to understand, and such will forever look like random background noise phenomenon to us

@Dat The nicest example I can give is what I'm currently researching, i.e. hydrofoils. Airfoil performance of different shapes and sizes are compared via their lift and drag coefficients with respect to changes in Reynolds and Mach numbers.

@Secret Sure. The universe is not required to fit inside our brains.

@ayc Then define choice. I'm sure there's some tautological definition going on here

What really is choice if the mind is just an emergent phenomenon from the brain (No I am not advanced enough to discuss the alternative where there exists a nonphysical mind, so stick to materialism for now)

@GodotMisogi I understand what you are saying but the problem is: The Navier Stoke equations I used to know are exactly the same the equations on NASA site. The only difference is Re and Pr number

@GodotMisogi Re number is in order of 10^4. How can they be the same ?

@GodotMisogi If you are to choose b/w A and B then whatever you are gonna choose is your choice

Also, the philosophy of choice is complicated by the question on who or what is the agent that made the choice. And from that it goes into the rabbit hole of what is the Self

@Dat Yes, these are non-dimensionlised with respect to something called "freestream (or reference) values". You usually scale your viscous terms and diffusion terms with these "similarity parameters" so you get results independent of your choice of fluid in an analysis

There's a whole tower of concepts need to be defined properly before we can even start talking about freewill

@ACuriousMind It's just a world I Described to lay emphasis on my statement:determinism implies nihilism.....Lets say you are right about so called hiddden variables......Then no world is meaningful...so nihilism is true..right?

Usually the motivation is to observe changes solely as a result of changes in geometry, but a more precise statement would be "to strip the analysis of functional dependence on properties of a fluid"

Note: I'm not an expert in this, and I'm only speaking from my experience of dealing with such cases

@Secret I fear that everyday...That what if we are biologically constrained to know only a little of the world we live in

@ayc We may never knew we are constrained. The best we can do is to get as close to that boundary of comprehension as possible and that is what we as a species have been always doing driven by curiosity

There are things we don't know we don't know that we don't know we don't know

@ayc Nope. I fully subscribe to the existentialist viewpoint that everything has precisely the meaning we ascribe to it, no more, no less. Nihilism is only true if you decide to not see meaning in anything

I, for one, see meaning in many things, without needing to believe anything specific about the determinism of the world.

@ACuriousMind As a existentialist could you oppose to the way I have come in ...i.e Just tell me why life is meaningful if whats gonna happen next is already predetermined by physical laws

As for me, even in a deterministic world, the "world script" ascribe meaning and purpose to existence and how they interact

and in theory, you will not see the meaning is in a sense, "artificial", because even your thoughts are scripted to see that e.g. A has the meaning of B

@ayc Why should I care whether the world is determined or not? Does it make the sun shine any brighter, the food taste any better, my friends any kinder, the rush of the moment any more intense?

@GodotMisogi but then some terms is multiplied by 1/Re

@GodotMisogi is that normal if I multiply some terms in continuity equation with 1/Re number ??

@Dat No, because the continuity equation has no viscous or diffusive terms.

@GodotMisogi yes, but I thought if momentum equation have Re number (like on NASA site) there would be huge different from theses momentum equations that I am used to know

@ACuriousMind How about just to know if it is or not, for curiosity?

@Did you look at the momentum equations at page 76 soaneemrana.org/onewebmedia/…

@Dat Yes, I'm trying to formulate an explanation for you

@GodotMisogi please look at equation (2.56a) at page 76 and the x-momentum equation on NASA site. How they just simply multiply some term by 1/Re ?

@ACuriousMind If the world's deterministic then it doesn't really matter if your friends are kind or just harsh.........because your friends nature of being kind or harsh is a result of the complicated biological processes that happen within his/her mind and the effect of their nature on you doesn't really matter, for even your reactions/opinions on their nature are also a result of biological processes

Pure chance the bing bang happened

@GodotMisogi I...really don't care! If you do, good for you, but I've stopped caring about determinism a long time ago

Obviously there would be one earth in infinity

Am just lucky to be born

@ayc I assure you all these things matter to me regardless of whether I conceive of them as the result of "biological processes" or not

@GodotMisogi neglect body force. the Left hand sides are the same. right ? Pressure gradient is same, . but how they just multiply viscous forces by 1/Re

@ayc So your definition of free will is: The ability to choose, and the meaning of life is having the ability to choose? The messages in the chat you have linked to have problematic statements that are making it unclear for me to understand how it relates to 3. You could just start with "Let A be a Theory of Everything, then..." instead of the disproving statements

@ACuriousMind To be honest,whether they should matter or not are also a result of those biological processes....its just how you have evolved....

@GodotMisogi could you be specific on what's unclear?

@ayc I mean, just repeat the consequences of having a Theory of Everything (claimed to be Z) here

i thought it was well known that the universe is not determinisitc. prepare 2 quantum systems in the exact same state, make a measurement. it can differ according to which system is being measured

it also means that if by magic one would recreate the past at a particular time, its evolution would differ from the one it had originally followed

@tttt It is not known whether the universe is deterministic nor not. The standard interpretations of QM say it is not, but e.g. Bohmian mechanics says it is.

ok

@tttt I think determinism here refers to whether you can at least write down on paper all possibilities that can take place using a theory of everything, and that our "consciousness/free will" has no effect on this.

damn it i didint know this im toast

The critical point is, of course, in your phrase "the exact same state". A determinist has to believe in hidden variables that differ between what we ordinarily call "the same state"

Bell's theorem tells us that our world is not described by local hidden variables, but it does not preclude hidden variables altogether

i thought hidden variables were discarted

ah

@Dat Sorry, give me some time. This notation is confusing me too, and is different from what I've seen. I think the variables themselves might be non-dimensionalised here

ok for now ill stay an atheist and believe in copenhangen or whatever the standard qm interpretation is

@tttt But Einstein himself said he believes He doesn't play dice. (/shitpost)

@GodotMisogi If A is a theory of everything,then A can and should explain what it claims to i.e everything.If it can do so then the evolution of universe,I would say,is governed by A.That is,future can be determined by A .If future can be determined by A then if I were to choose between "1" and "2" the choice I'm gonna make is already predetermined by A.What I'm about to choose is something like:written in a book you can nver read,but it is surely written

@GodotMisogi you think the variables in equations on NASA site are non-dimensional ? But they have give nomenclatures at the top of the site

@GodotMisogi A valid interpretation would be that God can't play dice if he doesn't exist! :P

God can of cause play die if he does not exist (=is empty, and all forall statements is true for empty sets) (/ultrashitpost)

lol

@Dat I know, that's why I'm confused :(

I mean, on first look, you can tell the equations on NASA care about the density of the fluid because it's general enough to consider steady and compressible cases, but they're scaling the viscous and diffusive terms.

can we talk ohusics here

What's 'ohusics'? :P

sorry physics

oh, sure

why NASA is so secret

@kartikc.p How is that any physics?

i am new here

@Secret russell = [ russell | russell <- [[..]] ]? (Haskell syntax)

@kartikc.p No,I just asked in a funny way....go ahead....

ya thinkin

@GodotMisogi what is [[..]]?

Guys,I should eat....I'll be back....I hope you will think ofsome great ideas to oppose me....

@Secret Set of all sets

Russell class is the class which the set of all set maps to itself?

is any body workin in nasa

@ayc This theory of everything should be able to incorporate a definition of time and the concept of time-evolution that you have referred to as well, and I'm pretty sure something might go wrong there

I feel like this is going to approach Gödel's incompleteness theorems

@Secret: Sorry, that was wrong. It should be: russells = [ russell | russell <- universe, russell elem russell]. The syntax is a list comprehension, which is sorta equivalent to set-builder notation

@GodotMisogi if they are scaling, did they forgot 1/(gamma)*M^2 in front of gradient p

you all sitting and chatting . and simly what if it is illusion

@Dat The derivation I'm used to non-dimensionalises the variables like velocity, pressure, etc. and the derivatives, so u → u*, x → x* and so on..., then the Re term appears in the denominator of the momentum equations in the non-dimensionalised Navier-Stokes equations.

@GodotMisogi ok, I got it now. Thank u so much

@GodotMisogi Why something might go wrong?...and what is that wrong?

@kartikc.p If it is an illusion, then (we don't know that we don't know that) x infinity it is an illusion

and thus it does not matter

just think little more

i am basiclly thinkin how can there be without nothing

i heard most of the scientists left handed like tesla enstien , thomson , newton , da vinci is a myth

@ayc suggest you read more on your questions/ musings. they are starting to remind me of this famous book, recommend it, you might enjoy it, see where all his pondering got him... o_O there is some complicated attempts to turn it into a movie en.wikipedia.org/wiki/Zen_and_the_Art_of_Motorcycle_Maintenance

@kartikc.p Few things I would like to tell you:1)If you wanna say something to a particluar person then type this:@NAME OF THE PERSON.....2)If you wanna talk referring to a particlaur message or wanna reply to a message use the small arrow that is there to the bottom right on that message which appears once you place your pointer on that message

last one thing before i go to bed what is this exactly 369 of nicola tesla he said its somthing key to universe when i saw some viodeos its mindblowing i beleve there somthing relation between 369 i think he was analysing the universe in geometrical scales

@ayc sorry

@kartikc.p I'm afraid that you are very hard to understand. Using punctuation and forming complete sentences would make that a lot easier.

@kartikc.p Nothing to apologize for......Keep chatting :)

@bolbteppa hey just saw spiderverse yesterday, really fun movie, great art, critics luv it, + theres a bunch of wild scenes with a massive device/ world-threatening machine that looks exactly like the LHC, and look who built it! :o o_O :P imdb.com/title/tt4633694

@vzn What's it about.....put it briefly!

@TheDarkSide Good to see you again..actually I cant see anything you are just dark....I'm a racist..lol.....Nice dp!

@ayc anybody lefty here . he will be the genius 😢

Hi.

@kartikc.p Could you explain in a better way as to what you are saying?....I can't get you!

What better seasons' greetings:

The single most amusing stack on SE !

Santa defends himself by blackmail ...

:: Sigh ::

Well, he does know who's been naughty...

Hey @ACuriousMind. Long time.

How've you been?

How hard it must have been to fit a hat to a face that's turned at an angle ...

@ACuriousMind Great. I keep amusing myself with WB Stack every now and then.

Not hard at all - the top hat also fit perfectly :)

thats amusing

@ayc dude oh geez try reading a link or two, it takes time to dig em up :P ... ok chat is fun but what are you gonna learn about life merely talking to random chat lurkers? :P

@ACuriousMind The specs yes, but what about the side scarves on that hat? :P

@ayc lol

Tao came from Nothingness, and Nothingness came from Nonexistence

From Tao, all natural laws follow

synchronicity... was just gonna reply on that :)

@vzn I just wanted to know what it was baout.."briefly"...If it might have seemed related I probably wouldve read it

@ayc try "briefly" reading/ skimming the wikipedia article or does your browser not support clicking on links? :P

All is nothing, until Nidana came and go and produce phenomenon

---Buddhism in a nuthshell

@Secret the future is already here its just not evenly distributed —Gibson

@Secret the Tao is in all things incl QM :) ps Mitchell has a really great translation, my favorite... :)

@vzn I did skim....It didn't seem related....so if I thought maybe If I ask you for a summary,since you suggested the book,you might relate it to my situation. Then I would know how its related to me and might develop some interest in it

@ayc everything is related to philosophy. the author pondered deeply, even obsessively, similar questions to those you are pondering. he was trying to come up with a philosophical TOE you might say. his life did not go in a "predictable" direction. it might be both a confirmation + refutation of some of your ideas... Zen is like that sometimes :P ... ps maybe life seems meaningless to you because youre still in HS lol :P

I am more interested on the essence of ineffable than the meaning of life, because one cannot understood the meaning of life without understood the ineffable

@vzn What's HS?..

But even this is not correct, I am interested in ineffable for its own sake

@ayc high school. ps the book was recommended to me by a great HS teacher. did not follow up on it until maybe more than a decade later... should read it sooner! :)

@Secret the ineffable cant be understood with the rational mind, thats kind of a lot of Lao Tzus point it would seem :)

@vzn I'm gonna add it to my list!

@ayc lol add it to the top of your list and get started now! :P you have a list? sounds like something to blog about :P

@vzn Don't forget that [Data expunged reason that if I said it will lead to me being risk permabanned] that lead me to be obsessed of nothingness and nonexistence in the first place. If I can experience sunyata, it should not be too far off to go one step further into Nirvana and then return from it

I have a very strong affinity to the concept of nothingness, to the point it takes form

@vzn Not a great list...just about few books...I don't really read books...so I just add suggestions to my list and read when I feel like doing nothing else..and I feel so very rarely...btw

The first 7 chapters of Tao Te Ching seemed to suggest Tao has very close relationship with nothingness, thus it might be possible for us to "communicate"

@ayc lol had a feeling. yeah the masses are like that these days. its a pity, it will stimulate your neurons. maybe you are more into social philosophy :P

Since I am obssessed with nothingness, my mind is very far from rational, lol

not to mention I have fine arts friends that help me go further from analytic

@Secret yes Taoism does seem to have a lot of connection with buddhist ideas, but the actual historical connections seem to be murky. just read long book that tried to unravel that...

@vzn what will stimulate my neurons...and why social philosphy?..it isn't a logical thing to study or give a thought about

Tao Te Ching is a very entertaining read, and it will make you very calm and still

It is basically the art of doing something by doing nothing

@ayc reading. "social philosophy" was joke, you seem to want to build/ analyze a (personal) philosophy by socializing...

Btw, I have a metaphysical cosmology that goes like this:

@Secret it makes a whole lot of sense that the deepest secrets of the universe would be discovered/ uncovered by... an itinerant poet :P

@Secret I'm interested .if it doesnt include all those weird named stuff youve been talking about until now

(Optional) God (>=(hierarchy does not apply)) > Unknowable > ... > Unknown Unknown > Unknown > Mysteries > ( Arcane > Ineffable > Magic and Divine )=metaphysics > Physics

I am weirdness incarnate, the least you can expect is for me to not be weird

@Secret All I can understand is that God > physics according to you

except I don't really like God in Abrahamic religions, because He is often portrayed as too personal and human

I like an impersonal Godlike force more than a personal God

Because I want something deeply unhuman

@Secret I like to look at physics as godlike......If GOD stands for Generator,operator,destroyer...then physics or perhaps the laws of physics do all of those....Generator(universe has been created by physical laws),operator(the laws of physics are upon which we mere humans operate),destroyer(one of the possible ends of the universe,also governed by laws of physics)...If you say universe is everlasting i.e never gonna get destroyed...I cannot argue..I'm not qualified to talk about that

I can talk about cosmology purely in the physical realm, but I can also talk a bit about cosmology in the metaphysical realm, due to some exposure to Baha'i, Buddhism, Kabbalah, Taoism and Hinduism. Technically which one is true does not matter to me, because we might never can check it

@Secret for afterall we are mere mortals

indeed

@Secret and also pathetic

perhaps we should take pride for being at the top of the food chain..I think that fact is arguable...lets just say that we should take pride for having reasoning abilites

Fun fact: It is SCP-055 that makes Tao Te Ching easier to understand for me

Apparently there's a Doctor Who marathon all the way through new years. My productivity has been doomed

can a black hole be considered as a quasiparticle? if so, would it be a boson, fermion or none of these?

We do not have a proper quantum description of black holes.

this means no wavefunction?

Does no hair not somehow go along with some "particleness"?

That's more of a classical notion of a particle though I suppose

@tttt It means we do not have any widely accepted theory in which a black hole is considered as a fully quantum object.

has anyone heard of the book Methods of Quantum Field Theory in Statistical Physics ?

kmk, nnfss ,,mm, lk'[

Is there such a thing as a "multiply-connected tree" or would that just be a directed acyclic graph?

I would just call that a DAG

Possibly relevant: en.wikipedia.org/wiki/Tree_(data_structure)#Generalizations

@tttt Probably not, but who's the author?

Ahh I see. I was actually wondering the difference between a dag and a tree a couple weeks ago and it just occurred to me that I haven't seen a tree where a node had multiple parents...sounds like that's the case from the wiki

@DavidZ ,.. Abrikosov, Gorkov and Dys....

apparently it's one of the most popular book in condensed matter

Ah, well I'm not familiar with that one. To be fair I didn't do condensed matter.

@danielunderwood Actually now that I look at it, it seems like the Wikipedia article is treating trees as analogous to undirected graphs. I guess it makes some sense because the parent-child relationship can be traversed in both directions, but still there is an orientation of some sort which undirected graphs don't have.

I think that DAG is the usual term for a "multiply connected tree", but I think that an argument could be made that it is useful to distinguish general DAGs from those that have a single root (that is exactly one node that only has from links).

A general DAG can have multiple roots. A useful fact if you are writing a Makefile, for instance.

huh I never thought of a makefile as a DAG...interesting

Here's an old answer that contains only links but they're good links, and it could use some elaboration if anyone is inclined to do the "legwork":

Yeah I'd imagine so. I think they're generally what underlies stuff like luigi or airflow, but never thought about good old make