The h Bar

i was looking around and I see from this indicates there is some sort of connection between phase and polarization (I was going to ask a question on the main site to clarify) but generally, is it easier to detect polarization than phase?

I.e., if phase and polarization are connected, if I change the phase, can I look at the polarization of each photon and see if it has changed due to the change in phase?

Avantgarde

1:50 AM

@DanielSank Raiders is right. You have an excellent question. Need a list of all such terms and notations

Mostafa

3:04 AM

A few suggestions:
SI (system of units), formerly called MKS
Celsius scale, formerly called the centigrade scale
MRI, formerly called NMR

The Raiders of Las Vegas

3:43 AM

Sorry about not doing my homework before commenting @JohnRennie

John Rennie

5:10 AM

@TheRaidersofLasVegas I don't think you should pay too much attention to the finer details of British grammar. A lot of the rules are pretty arbitrary and in any case the language changes continually. It's just that I wouldn't start making statements about physics if I wasn't pretty sure I understood the physics involved.

Dawood ibn Kareem

5:28 AM

@TheRaidersofLasVegas My mother had the habit of castigating supermarket cashiers serving at the "12 items or less" lane for the alleged poor grammar of the sign.

John Rennie

Criticising people's grammar can be great fun though it doesn't make you many friends :-)

Dawood ibn Kareem

Yeah, and it makes their grampars angry.

Avantgarde

5:47 AM

@Mostafa Really? I remember some experiment we did in college, where 'NMR' was used.

@DawoodibnKareem Should be 'fewer' instead of 'less'?

John Rennie

@Avantgarde Yes

Dawood ibn Kareem

6:02 AM

@Avantgarde Arguably, yes. It depends on whether you regard grammar as a set of rules that must be obeyed, or as a description of how people actually speak and write. I believe that most native English speakers would indeed say "less" in that context - and in my opinion, that makes "less" correct by definition. However, people who are sticklers for the rules of grammar, such as my mother, would insist that "fewer" is correct and "less" is wrong.

Sid

Eh, if it is understood by the people, that means it is "correct".

Mostafa

@Avantgarde eh, how old are you? ;)

John Rennie

@Sid The style in which you speak or write can be used to subtly affect the impact of what you are saying. If you communicate in a way that is ostentatiously grammatically correct it tends to make your statements sound more precise and therefore more plausible.

While I agree with you that we shouldn't worry too much about grammatical precision you shouldn't underestimate its importance in some circumstances.

Dawood ibn Kareem

6:25 AM

@Sid A large number of people define "correct" differently from you. There are plenty of contexts where pandering to those people matters. For example, if you are publishing a brochure advertising the services of an educational institution, it would be wise to ensure that the spelling and grammar contained therein conform to certain common norms. Because there are many such contexts, it is advisable to learn the rules of spelling and grammar, whether you intend to follow them or not.

Sid

it seems my comment above has been misunderstood. I agree that grammar and spelling are important in official documents, (say) a presentation in a meeting or formal talks. I mean that in informal stuff like when you are among friends or buying groceries, etc. grammar shouldn't really matter much as long as it is understood by people.

Secret

-3

Q: If I spun a ring singularity fast enough would it become a sphere? If so, then how fast?

I know that a spinning a black hole creates a ring, so does spinning a ring singularity in a additional axis at a sufficieny speed create a hollow sphere if so at what speed?

Presumably since we cannot have hollow sphere structure of infinite density matter in 3D+1T spacetime, doing so is likely to collapse the singularity into a point

But (not awaring that it might actually violate GR in some unexpected way) this question is quite interesting. I wonder if rotating black holes can really have such gimbal lock like motions

The Raiders of Las Vegas

6:42 AM

in English Language & Usage, 2 hours ago, by The Raiders of Las Vegas

in Language Overflow, 22 hours ago, by V.V.

Secret

What is known however is that we probably cannot apply the hollow sphere event horizon argument to this question as the singularity, whether ring shaped or point like, is already supposed to be the end state of a gravitational collapse and thus have no room to collapse further

John Rennie

@Secret: since angular momentum is conserved it must be constant i.e. have a constant magnitude and a constant direction.

Secret

ah right, and that gimbal lock motion suggest by OP will have the direction of the angular momentum constantly changing thus it will violate conservation of momentum

John Rennie

Yes

Secret

Lion-Eating Poet in the Stone Den

The Lion-Eating Poet in the Stone Den (simplified Chinese: 施氏食狮史; traditional Chinese: 施氏食獅史; pinyin: Shī Shì shí shī shǐ; literally: "The Story of Mr. Shi Eating Lions") is a passage composed of 92 characters written in Classical Chinese by Yuen Ren Chao (1892–1982), in which every syllable has the sound shi when read in modern Mandarin Chinese, with only the tones differing. It is an example of a one-syllable article, a form of constrained writing possible in tonal languages such as Mandarin Chinese. == Explanation == Classical Chinese is a written language and is very different from sp...

John Rennie

6:50 AM

There is a Thai tongue twister that some friends tried to teach me when I was in Thailand. From memory (not necessarily reliable) it's kai kai kai kai but because Thai is a tonal language all four words mean something different. I think two of the meanings are rice and white, but my memory fails me for the other two.

user228700

Hi, everyone :-)

John Rennie

Morning :-)

user228700

I'm going to watch a movie early in the morning tomorrow!

John Rennie

Which film?

And why early in the morning?

user228700

@JohnRennie Dunkirk.

user228700

7:01 AM

Oh, it's not too early; it's at 9:20 AM.

John Rennie

At the cinema?

user228700

Yep. On my own, as always.

Sid

@Kaumudi.H According to my friends, Dunkirk is exceptional

user228700

Right. The reviews really are great.

user228700

7:04 AM

HANS ZIMMER! Whoa!

John Rennie

I'm toying with the idea of going to see this

user228700

John Rennie

That's odd, it works here. Maybe it only allows UK IP addresses.

It's this film

user228700

Ohh, cool :-) Are u a fan of the band?

John Rennie

I've been a fan of Black Sabbath since I was about 11 years old :-)

user228700

7:15 AM

Ah, wow, nice :-)

John Rennie

This is their first album - one of the all time classics

The chat goes quiet - stunned by the awesome music of Black Sabbath

user228700

Haha :-) I was busy booking movie tickets for my family. And now I have a crisis at hand because I've absentmindedly booked 5 tickets instead of 4.

user228700

> Once tickets have been bought online, they are considered sold and cannot be cancelled, refunded or exchanged.

user228700

Sigh. Now I too will need to watch the movie with them; two movies in one day!

John Rennie

You're going on your own to the early screening, then with the family to a later screening?

user228700

7:26 AM

No, no, the one with my family is a different movie. It's a Malayalam movie.

John Rennie

I did wonder if the twins weren't a bit young for a war film :-)

user228700

:-) Not only that; they'd also struggle to understand. They're not exceptionally fluent in English.

John Rennie

Oh well, two films in one day. It's a hard life but sometimes you just have to step up to the plate :-)

user228700

Haha :-)

user228700

When's the screening of the movie on Black Sabbath?

John Rennie

7:29 AM

Will Dunkirk have subtitles?

On that subject, did you get the headphone adaptor? Does it work OK?

user228700

@JohnRennie I dunno. I do hope so; it might be difficult to understand what with all the bombing noises in the background.

user228700

Sometimes, cinemas here do display subtitles for English movies; that was the case when I watched TFiOS and Gravity but I can't be sure of this one.

user228700

AHA, my family's inviting a friend to occupy the 5th seat. I don't have to go! :-)

John Rennie

Saved from a fate worse than death!

You get to stay at home and surf NetFlix?

user228700

:-P #FirstWorldProblems amirite?

user228700

7:33 AM

@JohnRennie No, my subscription to Netflix ended. I get to stay at home and...do whatever, really. Read, perhaps.

John Rennie

I'm currently reading a book about teeth ...

user228700

Fascinating! :-P Which book is it?

John Rennie

This one‌. It's turning out to be very interesting.

I read New Scientist magazine every week and it has a book review section. Not all the books they recommend are great, but I've read some very good books as a result of their suggestions.

The Raiders of Las Vegas

Did you get a chance to watch the Hawking clip I linked? @JohnRennie

John Rennie

Just as well because the last two books I've read have been very disappointing and I needed a good book to break my losing streak.

@TheRaidersofLasVegas yes.

I'm not sure how much trust we should put in Hawking's memories of why he chose Cambridge

Memory tends to be selective on these issues.

The Raiders of Las Vegas

7:39 AM

Absolutely :-)

John Rennie

At PhD level it's as important to choose the person you want to work with as it is to choose the university. It may well be that Hawking particularly wanted to work with Denis Sciama, though rumour suggests he really wanted Fred Hoyle.

So he may have chosen Cambridge specifically to work with those people.

The Raiders of Las Vegas

Penrose has an interesting biography also.

Slereah

@JohnRennie oh man

It would have been really awkward if he chose Hoyle

people only remember Hoyle for being a kook now

John Rennie

@Slereah Yes :-)

Slereah

I'm trying to reformulate Hoyle's theory rigorously for the book

i'm not 100% sure how

It was fairly ad-hoc in Hoyle's original paper

John Rennie

7:53 AM

The steady state theory?

Slereah

Though maybe I should look into his quasisteady theory

yeah

Basically you have a vector field $C^\mu = \alpha (1,0,0,0)$, and this gives rise to the creation field $C_{\mu\nu} = \nabla_\nu C_\mu$

John Rennie

He had a point about the Big Bang. I guess we all just learned to live with singularities.

Slereah

Well his theory wasn't bad, it just turned out to be incorrect

But I think he burned a lot of bridges by being a huge dick about it

John Rennie

I think he lost his marbles a bit in his later years. It happens I guess.

user228700

@JohnRennie Ooh, interesting!

user228700

7:56 AM

(Sorry about that; needed to go out to buy some banana chips)

John Rennie

@Kaumudi.H At the moment there seem to be lots of good popular science books pitched at the informed amateur.

i.e. they are for the general public but expect you to be reasonably well informed and willing to put some effort into reading the book.

user228700

Ah, right, right. I'm certain that it won't reach the general public, then.

John Rennie

But I think when I was a student I was so focused on my work that I wouldn't have been interested in books like that.

It's only now I have the time to explore other areas like palaeontology, archeology, etc

user228700

Ah, right, of course.

John Rennie

Got to work for half an hour or so. Back in a bit ...

Dawood ibn Kareem

8:07 AM

@JohnRennie There's something very similar in Serbian/Croatian, which is partially tonal. Gore gore gore gore means something along the lines of forests burn worse upwards (actually I don't remember exactly what it means). The four words are distinguished partially by vowel length and partially by tone.

Mostafa

9:22 AM

@DawoodibnKareem nice :)

There are some similar funny combinations in the local accent of my hometown (some accent of Persian). For example, "Ne ne na ne na" means "hey, they're our mothers" :)

Dawood ibn Kareem

10:09 AM

Are the "ne"s all the same?

Mostafa

No, totally different (only sound the same)
It's actually "nene(mother) + nane(makes "mother" plural + are) na(=something like *hey*)" :D

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