The h Bar

0celo7

12:19 AM

Oh please tell me you're kidding

I think he introduces frame fields in the last chapter

What the hell

vzn

1:12 AM

@DanielSank no disagreement dude! :) (oh and guess who lobbied for most of its votes?) huh, do you think EP will delete all his hostile comments on it now? voted on his new ad without complaint! oh whatever it doesnt matter now... anyway have all kinds of grandiose ideas/ plans for further domination but dont wanna rush it for now, its an awful lot of paradigm shifting in a short time already for everyone around here to deal with :P

DanielSank

@vzn Dude, the comments are not hostile.

Why do you call anything that challenges your opinion "hostile"?

vzn

@DanielSank lol why not? :P

DanielSank

@vzn facepalm

vzn

@DanielSank dont call all the challenges hostile, just the hostile ones :P

DanielSank

@vzn Right...

Also, for whatever it's worth, if the ad had been done properly in the first place (a useful link) it wouldn't have gotten down votes and there would have been no need for campaigning.

Furthermore, I suspect the starred chat message that was up for a while indicating that the link was fixed is probably responsible for most of the up-votes.

Of course that's just wild speculation on my part.

vzn

1:17 AM

← hey anyway am well familiar with "SE culture/ antics", coming up on my ~½ decade mark this year. some of the response is a small )( dramatization. :P

@DanielSank honestly, think your whole idea of the "proper way" to do "this"/ something in cyberspace is something of a mirage/ fantasy brought on by EPs pov, but luckily it doesnt alter the overall plan. :)

← still waiting on all the way cool graphics promised by at least 2 ppl on here, meantime the ad has run for weeks & gets hits

DanielSank

1:35 AM

@vzn That is one of the most absurd things I've ever read :)

You think my opinion that providing useful links on the internet is a result of EP's comments on one SE meta post?

Hello @DavidRoberts.

vzn

2:42 AM

@DanielSank the pt is we both took EPs ~~stinging~~ feedback into acct & made adjs & now we'll all live happily ever after, right? anyway hes been somewhat neutralized after being asked to be a guest speaker, maybe that was ~½ the trouble to begin with anyway :)

@Slereah & have you heard what carmack is up to these days? =D

vzn

3:05 AM

@0celo7 lol o_O sounds like noise to me. but lil wayne has a great song with jlo, betcha just luv that one (awesome video, bet she spent big $$$ on it!). oh yeah & jlo has a few great songs with pitbull, am sure youll luv those too! ps just went thru 6 mos of transcripts looking for you refering to a cool electronica music site, coulda sworn it was in here somewhere, maybe it was knife party, not sure now, cant find it again, shoulda saved it, lost in the shifting sands of cyberspace now :(

user116211

3:29 AM

0

Q: Criticism of physics in _The Beginning of Infinity_?

Have any criticisms been written of the physics presented in David Deutsch's book The Beginning of Infinity? Does he make any mistakes? If so, please refer me to them.

multiverse

user116211

Criticism of a book - Off topic?

user54412

3:40 AM

@MAFIA36790 I want to say yes, but I don't know quite what to point to. Perhaps too broad.

user116211

Ah! Thanks.

user54412

Also, this is definitely not the first time I've seen someone get strangely defensive about Deutsch after asking for verification of his books.

0celo7

@vzn Probably Beatport Pro

@ChrisWhite I've never even heard of the guy

user54412

3:57 AM

and... that thread got weird

user116211

please stop flaming me with psychological attacks like that i'm "defensive". and what are you talking about? i do know david deutsch personally. why are you making things up? — curi 7 mins ago

user54412

there's this bizarre line where some people can be pushed too far and they end up caught in an endless cycle of constructing their own mythos to avoid cognitive dissonance

user116211

This is extremely biased after you want criticism.

user116211

But as usual, no one can beat CuriousOne ;P

user116211

Hey @JohnRennie, morning.

user54412

3:59 AM

I know his commentary isn't popular around this bar, but I can't help but agree with a lot of what he says (like this), if not how he says it.

0celo7

I wonder what Pokemon learn heal block

Or maybe I need something with recover and then use a Ban Seed

Mewtwo is ridiculously strong in this game

John Rennie

Morning. 5 a.m. start again - oh well :-)

user116211

The problem is that CuriousOne hardly knows how to modestly behave or write a comment; but here in that question, I totally agree with him.

user116211

@JohnRennie You always wake up at 5?

John Rennie

@0celo7 Speaking as one who knows nothing about Pokemon, there seems to be a lot of chatter about Pokemon Go at the moment ...

0celo7

4:02 AM

Well he holds that physics cannot make predictions

John Rennie

@MAFIA36790 I normally start around 6, but it's hot and humid at the moment and I can't sleep.

0celo7

hot?

on the island?

user116211

at the morning?

0celo7

What're the stats

John Rennie

You realise that for us English >20C is hot :-)

0celo7

4:03 AM

In good units please

user116211

ah!

user54412

@JohnRennie As someone of English genetics, I believe it.

John Rennie

@0celo7 $20*9/5+32$

0celo7

@JohnRennie what the fuck

it's currently 23C here

at midnight

77% humidity

user116211

It's 25 here and it's pretty cold ;/

user54412

4:05 AM

ah, but 77%F or 77%C?

0celo7

77%R

user116211

I damn like the Himalayan monsoon.

0celo7

@JohnRennie No clue what that is

user116211

@0celo7 what??? You don't know that?

0celo7

no

user116211

4:07 AM

hmmm....

user116211

google.co.in/…

0celo7

Time to ~~recruit Mewtwo~~ die a hundred horrible deaths

I wonder...do I have Sableye

nope

hmm

no Spiritomb either

@JohnRennie Umm, what happened to the starred comment "I am clearly the reason this room exists"

John Rennie

@ChrisWhite :-)

@0celo7 I didn't unstar it. I thought it was funny and made a point of leaving it there.

0celo7

I don't see it

user54412

wasn't me

0celo7

4:13 AM

We all know who it was

There's one person who despises me

Because he's jealous

user54412

just one?

user54412

people who only have one enemy in life are never remembered in the history books

John Rennie

yesterday, by 0celo7

I'm clearly the reason this chat exists

0celo7

Can I flag that as a sick burn

It hurts

John Rennie

Been unstarred

0celo7

4:14 AM

Why?

user54412

tbh I don't even see the star wall anymore -- enough uninteresting stuff there that I subconsciously block it

0celo7

I don't see what's wrong with it...

John Rennie

Well the star board is supposed to be for things that are about physics, not things we think are funny. I've unstarred my fair share of comments so I'm reluctant to criticise anyone else for unstarring.

0celo7

DAMN I can't get Goodra to come along on the Mewtwo battle :(

user116211

That would be like we only talk physics

user116211

4:16 AM

Reminds me of JD T__T

0celo7

Or Wobbuffet :(

John Rennie

When I made a comment comparing he who shall not be named to genital herpes it got 13 stars before one of the mods unstarred it :-)

user116211

BTW, has anyone checked the Trump twitter battle?

John Rennie

Does anyone care?

user116211

hmm.

0celo7

4:18 AM

Ok, I have a strat

Wish me luck...

YES

Shedinja is unaffected by all of Mewtwo's moves :D

So I just have to block his healing -- somehow, and then whittle down his health.

Crap the rest of my strategy failed

Ok, new strat: blast seeds + two ghost pokemon with curse + Shedinja

+ ban seed for mega Mewtwo's recover

+ spite

Going for the mega cheese

+ will-o-wisp

and 20 reviver seeds :D

YES

YEEEEES

HAHA

Curse is OP

John Rennie

4:45 AM

Is sharp observable an accepted term in Physics?

-1

Q: Is this statement of the Heisenberg uncertainty principle correct?

Is this correct? The Heisenberg Uncertainty Principle is not a Principle or law of physics. It's one of many results you can work out from quantum theory with some math: -- In quantum theory observables can be represented by Hermitian matrices. -- If an observable of a system can be represen...

uncertainty-principle

0celo7

18 floor "super difficult" dungeon to get Kyurem

Ok, I don't need to sleep.

user54412

@JohnRennie never heard it before -- perhaps lost in google translation?

John Rennie

I suspect it's from Deutsch's book. Curi just got flamed by CuriousOne for asking about the book.

user54412

ah indeed apparently Deutsch uses the term

user116211

You can't learn anything from a pop-sci book - it's universal fact.

user116211

4:51 AM

unless it is of Gamow.

John Rennie

@MAFIA36790 that's a bit harsh. I suspect many of us started by reading popsci books as children. I certainly did. As I recall Asimov has written some really good popular science books.

user54412

I'm starting to realize how lucky I am that my first QM didn't delve into interpretations and just did actual physics -- apparently this isn't true for everyone, and afaict thinking about interpretations just makes people start speaking in tongues

user116211

@JohnRennie As always, not a generalisation; but most of the pop-sci books are actually fruitless; you can't deny that.

0celo7

why does my Hydreigon have crap moves

John Rennie

Well I do at least partially deny it.

Popsci books have to sell, so their authors have to make them a bit gee whiz

And some authors take that too far

user54412

4:54 AM

@0celo7 evolve it to Heliomon using the pp chain stone

John Rennie

But I think most popsci books do more good than harm

0celo7

@ChrisWhite huh?

user54412

@JohnRennie I think I agree with this, though the good comes in small, hard-to-measure doses, while the bad sticks out like a sore thumb.

user116211

I liked the books of George Gamow and Wigner...... and bit of Hawking; but that's it.

0celo7

Hawking-Ellis is a terrible book

@JohnRennie How come Sam gets to call me a phillistine in the starred section

John Rennie

5:05 AM

@0celo7 I'll unstar it if you want me to.

0celo7

@JohnRennie We should, for consistency

John Rennie

It's funny because everyone has played DOOM - apart from you apparently ...

0celo7

We should also unstar the "iddqd" comment

Nothing of value there

John Rennie

Done, though I see my comment above has now been starred :-)

0celo7

Then the "just one?" and "you have agent to protect"

If we're not starring anything not physics you have some work to do...

user116211

5:06 AM

oh! c'mon dude ;/

user116211

We talk beyond physics here ;((

user116211

Only he promotes we should talk physics ;/

user116211

@0celo7 huh?

John Rennie

@0celo7 Generally speaking I only unstar stuff that's critical of individuals i.e. could be viewed as a personal comment. I guess the comments about DOOM fall into that category since they're targetted at you.

user116211

I'm not offending him ;/

0celo7

5:08 AM

@JohnRennie Then why was my earlier comment unstarred.

All I ask is for you mods to consistently apply the rules.

Why is that so damn hard?

John Rennie

@0celo7 I don't know because it wasn't me that unstarred it

user116211

@0celo7 John is not mod ;/

0celo7

@MAFIA36790 He has literally nothing to do with this

He's a victim too

user116211

@0celo7 JD?

user116211

hmm.

John Rennie

5:10 AM

NB I'm likely to trash any posts that mention our very own Voldemort. You have been warned.

0celo7

Floor 13

Almost there -.-'

John Rennie

I remember an Asimov popular science book from the 70s that went into lots of detail about the new stuff in particle physics. It even mentioned the Eightfold Way. But I'm damned if I can find it. You'd think it would be easy to Google ...

user116211

@JohnRennie when was it published?

0celo7

Damn, I'm dumb

I should have brought Metagross.

John Rennie

@MAFIA36790 can't remember, but I read it around '72-75.

user116211

5:13 AM

okay....

Jester Tran

Can someone explain to me what a delegate is in voting?

John Rennie

@JesterTran in the US presidential election?

Jester Tran

@JohnRennie yeah

John Rennie

Have you tried Googling it?

@JohnRennie I think it might have been 20th Century Discovery. The cover looks familiar.

It was quite an achievement to get SU(3) symmetry into a popular science book and make it interesting to a 12 year old :-)

Jester Tran

@JohnRennie Suppose we have 3 candidates for US pres. election and 2 delegates are elected for each candidate. Delegates are people who represent each party and try to get votes for their leader. The candidate with most votes attained by their delegates is winner?

0celo7

5:22 AM

@JohnRennie Wow, I didn't know what SU(3) was when I was 12

I still don't

SU(3) symmetry

I know what SU(3) is

John Rennie

@0celo7 see, you should have read Asimov's popular science books ;-)

user116211

@JohnRennie Okay, why do you talk to yourself?

John Rennie

At that time SU(3) symmetry meant the fact there were only three light quarks i.e. it was the approximate symmetry of permuting three quarks. QCD had yet to be discovered.

user116211

My all-time favourite is Gamow's Mr. Tompkins and One, Two, three,.... infinity; they are classic.

John Rennie

@MAFIA36790 it's the only way to get an intelligent conversation :-)

0celo7

5:24 AM

BOSS BATTLE TIME

LET'S DOOOOOO THIS

Jester Tran

@JohnRennie Am I right or wrong?

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

(removed)

John Rennie

@JesterTran I don't know, I'm a Brit not an American. We don't get to elect our head of state :-)

0celo7

Kyurem fainted.

Trivial.

Jester Tran

ok... this puts me off of doing a puzzle then...

user116211

5:29 AM

@0celo7: It's bed-time, dude; go to sleep :|

0celo7

@MAFIA36790 You don't think I should go after Entei next?

Or Zapdos

I've got like 400 pokemon left, can't stop now

user116211

Zapdos! Yeh, then go on.

John Rennie

7:24 AM

Apparently my answer is so unscientific as to not be worth be posted in this site:

Wave function collapse is a simple term that in reality involves decoherence of states. It is now well understood, and does not break unitarity in state evolution, or causality. Theromodynamics simply explains things from a practical point of view in terms of macroscopic quantities. The Thermodynamic arrow of time is also clear, entropy increases. The rest is either unknown physics, not mainstream, speculation, or just not science. This question, answer and discussion is so unscientific as to not be worth be posted in this site. — Bob Bee 26 mins ago

Oh well :-)

user116211

7:44 AM

@JohnRennie WTH is that last line?

user116211

7:57 AM

Saw the Fight of the Century.

user116211

Frazier vs Ali.

user116211

8:21 AM

I completely agree that the real numbers are a godsend (well... sent by a century of mathematicians, anyway), but they kind of detract a little from what physics really does, which is to compare physical quantities to other, more easily standardized physical quantities. The latter process, if taken literally, would be horribly pedantic, of course, so we borrow stuff from the mathematicians to fake it real good. :-) — CuriousOne 4 hours ago

user116211

Well, maybe; hmmm.

David Z

9:38 AM

2

Q: What things in our universe can be considered uncountable?

I am taking a course in mathematics that covers countability. The trick with the uncountability of the real line is that no matter how many times you divide up an interval, there would still be a real number inside of that interval so that even the smallest interval contains "more than infinite" ...

general-physics

off topic?

or rather, too broad, I think

And if anyone knows a good tag for it, that would be good. The original tags, particle-physics and universe, don't apply.

@JohnRennie you could flag that. A custom flag might be appropriate, as it doesn't quite cross the line into offensive territory.

user116211

10:27 AM

What a pity that one cannot downvote comments... — Yvan Velenik 29 mins ago

John Rennie

11:05 AM

@DavidZ Life is too short :-)

Secret

> You have the mindset of a theorist, but the tools and intuition of an experimentalist. While experimentalist worry about the results, theorist worry about how their model fit, you worry about where the model came from

What my friend said of me in the sliding scale of mathematician engineers experimentalist and theorist

John Rennie

@DavidZ On this issue, what does CuriousOne's comment mean:

The non-integrability of Hamiltonian systems guarantees that not even classical determinism survives. I think it's high time to let go of a failed 19th century idea that has no discernible physical meaning. — CuriousOne 5 hours ago

Is he saying that you cannot, even in principle integrate a system forward in time indefinitely? If so is he correct, and if he's correct, why not?

user116211

I NEVER understand CuriousOne ;|

Secret

11:20 AM

I am guessing he argue that determinism has no physical meaning since hamiltonian systems are not integrable

John Rennie

This is probably an ignorant question, but what does it mean to say Hamiltonian systems aren't intergarble?

"intergarble" - a Freudian slip there :-)

integrable

Secret

Well, I am not sure given that I don't even fully understood what "integrable" means in $L^2$ spaces

other than stuff don't blow up to infinity when you integrate them

John Rennie

Ah, you mean it isn't guaranteed there won't be a singularity if you integrate forward in time?

Secret

I am not sure if my understanding of "integrability" is full enough to say whether this is a yes

But the hamiltonian is a differential operator of some sort, thus one can attempt to integrate it like any differnetial equations does

Integrable system

In mathematics and physics, there are various distinct notions that are referred to under the name of integrable systems. In the general theory of differential systems, there is Frobenius integrability, which refers to overdetermined systems. In the classical theory of Hamiltonian dynamical systems, there is the notion of Liouville integrability. This causes the trajectories to be fixed to smaller submanifolds allowing the solution to be expressed with a sequence of integrals (the origin of the name integrable). More generally, in differentiable dynamical systems integrability relates to th...

John Rennie

I had already read that article, and the conclusion seemed to be that Hamiltonian systems are integrable in the sense that you can integrate their equations of motion forward in time. However it hadn't occured to me that there could be singular points.

Secret

11:35 AM

Hmm, what would approaching a singular point in motion mean physically?

John Rennie

For example in GR the equations of motion of a freely falling body become singular at the centre of a black hole. Or alternatively the FLRW metric becomes singular if you evolve it back to time zero.

As for physical significance, I'd guess most physicists think a singularity is a failure of your mathematical model rather than the real world.

For example you get singularities in fluid dynamics, but they just mean the continuum approximation has broken down.

Secret

which is why I am usually more curious about the neighbourhood of a singularity, because those places the system is still well behaved (is this the correct term?) enough to figure what is happening and whether there's something else going on other than a sign of a model breaking down.

For example, if something started to blow up towards infinity as it approach a singularity, then we knew this singularity is likely to not represent something interesting and more of a sure sign of either the model is breaking down, or that we are approaching something akin to what happens to the electric fie…

But if something that is not blowing up to infinity going on near a singularity, then it is worth further investigating what it could mean

(that's my thought anyway)

David Z

12:15 PM

@JohnRennie I don't think I could have told you anything useful about that

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

1:00 PM

I'm not so sure I agree with "this is our house" and we need to keep it clean so that the "average user" passing by doesn't get offended philosophy.

0celo7

@Secret See Arnold for a good discussion of this, he talks a lot about caustics in Hamiltonian systems.

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

@yuggib o/

yuggib

\o

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

How are you doing?

user116211

Hey @yuggib; evening.

yuggib

1:08 PM

@MAFIA36790 hey!

fine! today a lot of sushi

user116211

@yuggib ah!

yuggib

and shinto and buddhist temples

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Nice.

John Rennie

2:24 PM

@DavidZ Oops, sorry, it did look as if I was asking you when I was really just linking the thread.

ACuriousMind

2:39 PM

@JohnRennie I don't think he understands what "integrable" means :P

The better argument against classical determinism is Norton's dome

user116211

i remember there is a post on the same by QMech.

0celo7

@ACuriousMind I still don't understand that thing

ACuriousMind

What's there to understand? It's a shape for which the uniqueness theorems for the solution of the equation of motion don't apply, and therefore there are two valid solutions for the same initial condition

It's a counterexample, if you will :P

0celo7

I don't understand how that's possible

and the wiki article says it will "move down after some period of time"

what the hell does that even mean

and how does it not violate Picadilly-Lindyhopfer

ACuriousMind

Nah, it is a valid solution that it starts moving at an arbitrary time, but classical physics simple can't predict what happens to something at the top

@0celo7 The shape is not Lipschitz

0celo7

2:43 PM

how is that a valid solution

@ACuriousMind well there you go

reality is Lipschitz

ACuriousMind

Um...I don't know, the dome looks perfectly possible to me

I.e. I'm not convinced reality is Lipschitz

0celo7

what does it look like

@ACuriousMind Hmm

that does not look like a dome to me

wolframalpha.com/input/?i=x%5E%7B3%2F2%7D

oops

it's |x|

wolfram won't plot that :(

David Hammen

To me, Norton's Dome is not a problem in classical mechanics. The answer lies in Newton's 1st law, which says that the particle starting to slide down the dome after staying put for an arbitrary period of time is non physical. Newton's 1st law is more than just a special case of Newton's 2nd law.

0celo7

I don't understand how it could slide down without some perturbation

user116211

@DavidHammen I do agree with the last statement.

David Hammen

2:56 PM

Much more problematic with regard to integrability in classical mechanics are the non-collision singularities that result in the N body problem. For example, citeseerx.ist.psu.edu/viewdoc/… .

John Rennie

Come on Dr. Hossenfelder, tell us what you really think :-)

backreaction.blogspot.co.uk/2016/06/…

0celo7

::reads paper::

I don't believe it

Math no longer makes sense

ACuriousMind

@DavidHammen I always thought of the first law as asserting that inertial frames exist. How does it forbid the "unphysical" solution of Norton's dome in your view?

0celo7

I still don't know what an inertial frame is

Physics is waaaaay harder than math, no one defines stuff properly.

David Hammen

3:11 PM

@0celo7 Inertial frames are the canonical spherical cow of classical mechanics. If you can find even one inertial frame, you can construct an infinite number of other inertial frames by shifting the origin or by adding a constant velocity to the origin. The problem: You can't find an inertial frame. The best one can do is to posit that inertial frames exist. This is the modern view of Newton's 1st: It is an axiomatic statement that inertial frames of reference do indeed exist.

0celo7

@DavidHammen I know

But I don't really know what it is

David Hammen

An inertial frame is a frame of reference in which Newton's laws of motion (all three of them) apply. One way to look at Newton's laws is that the third law truly is a universal law that applies in all frames of reference. (This of course ignores electrodynamics, relativity, and quantum mechanics.)

0celo7

Let me rephrase

I know the definition

I'm not sure what it means though

David Hammen

In this point of view, inertial frames (Newton's 1st and 2nd laws) are special cases where the equations of motion take on their simplest form. One way to make Newton's 1st and 2nd laws appear to apply in non-inertial frame is to fabricate non-existent forces out of thin air (the so-called fictitious or inertial forces) so that Newton's 1st and 2nd laws appear to apply.

John Rennie

In a (Cartesian) inertial frame all the Christoffel symbols are zero

0celo7

3:22 PM

@JohnRennie What?

John Rennie

I had to put (Cartesian) in otherwise some clever dick would point out the Christoffel symbols are non-zero for polar coordinates even in an inertial frame.

Which bit of my succinct, precise and wonderfully elegant definition did you not understand?

0celo7

Because that's not a postulate, one can always find frames on $\Bbb R^3\times\Bbb R$ in which the Christoffel symbols are flat.

@DavidHammen just said the existence of inertial frames is a postulate

Or are you saying it can be replaced by the assumption that we are working on a 4-dimensional affine space acted upon by the Galilean group?

And then you define inertial frames based on Christoffel symbols?

David Hammen

@0celo7 Do that and you're going to get different, and more complex axioms. They're always hiding somewhere.

John Rennie

I have some important business to deal with - talk amongst yourselves for the next few minutes. Specifically I have this important business to deal with:

David Hammen

@JohnRennie Looks tasty! What is it, and what are you drinking? That's a beer glass, but the contents don't look like beer.

John Rennie

3:30 PM

@DavidHammen Pasta, bacon, tomato, chillis with toasted cheese on top. The pink beer is grapefruit juice :-)

David Hammen

@0celo7 Yes, you could define classical inertial frames in the sense the John Rennie stated. Proceed down that path and the problem of Norton's Dome becomes quite real.

0celo7

Let's see what Arnold says...he might require that forces are Lipschitz.

John Rennie

@DavidHammen But doesn't Norton's dome just say there is no such thing as a perfectly unstable equilibrium?

David Hammen

@JohnRennie Ooh! Better than the maple bacon donuts I brought to my new job last Monday, along with lots of other goodies. Nothing like a heart attack on a plate!

0celo7

@JohnRennie It has nothing to do with stability

You can literally have a solution that just starts moving

No perturbation

David Hammen

3:36 PM

Norton's dome is a weird beast. The singularity is second order, as opposed to an inverted pendulum where the singularity is first order.

0celo7

Why does my HE comment have two stars

Danu

@ACuriousMind do you happen to have a solid understanding of lens spaces?

@JohnRennie Nice!

Also hi @DavidHammen :)

David Hammen

Last Monday was a donut extravaganza. I asked how many people attended the Monday morning tag up and bought appropriately. $60+ dollars worth of donuts, kolaches, and other stuff. Two interns also started on Monday. Both came in with a nice amount (for interns) of new guy donuts. We had donuts everywhere!

Danu

> I care about math only to the extent that it’s useful to explain the world.

Where I stopped reading

David Hammen

By the way, I am now an ex ex rocket scientist. My foray into being a greedy ex rocket scientist is a thing of the past.

Danu

3:42 PM

@DavidHammen Congrats on re-entering research, if I understood that correctly!

user116211

@0celo7 You wanted more?

David Hammen

@Danu -- We know what we're doing, so it's not research by Einstein's definition. I'm rejoining the somewhat low paying space exploration crowd. (That's not quite true. I am compensated quite nicely; I've seen the salary curves. I'm just not as well compensated as I was a month ago. Then again, I probably did too good a job at Salary Negotiation 101 in that previous job. I was making more than a congress critter. I made damn sure of that.)

0celo7

@MAFIA36790 no

Danu

@DavidHammen OK :)

So what are you going to be exploring?

user116211

@0celo7 oh.

Slereah

3:52 PM

0

Q: Field solution for spacetimes with identified regions

For a spacetime surgery wormhole, we have a manifold such that, for two connected compact sets $D_1$ and $D_2$, we remove $D_1$ and $D_2$ from the manifold and identify their boundaries. According to Friedman, solving fields on such spacetimes just requires the added conditions that, for $x_1 \in...

quantum-field-theory field-theory topology wormholes

halp

M Barbosa

I need to get this off my chest: The Physics SE logo looks like a sombrero when it's minituarized. Thanks.

David Hammen

@Danu I'll be working with some NewSpace ventures and some old space ventures who have lots of fires that need to be put out, once again working a bit (tiny bit) with the physics engine I architected a decade ago that is now used in many of NASA's simulations, helping writing/costing proposals, plus a bunch of other stuff that I cannot talk about (yet).

Slereah

Well it is called a hat potential

0celo7

haha implying you'll get an answer

you'll get a comment from CuriousOne telling you wormholes are unphysical

John Rennie

@MBarbosa It's commonly known as the Mexican hat potential

0celo7

3:54 PM

One from JD when he's unbanned saying you're not smarter than Einstein

Maybe some nonsense non-answer from Timaeus

If you're lucky