Particle Physicists Confirm Arrow of Time Using B Meson Measurements

Arrow of Time... by Anonymous Coward · 2012-11-19 11:53 · Score: 5, Funny

Arrow of Time confirmed... Wheel of Time fans disappointed.

Re:Arrow of Time... by Anonymous Coward · 2012-11-19 11:59 · Score: 3, Insightful

Thus is our treaty written; thus is agreement made.
Thought is the arrow of time; memory never fades.
What was asked is given; the price is paid.
Re:Arrow of Time... by girlintraining · 2012-11-19 12:46 · Score: 0

Arrow of Time confirmed... Wheel of Time fans disappointed.
I've been disappointed since I realized the books were very engaging, exceptionally self-consistent, and... not only sexist but was a central component of the story. That sorta ruined it for me.
-- A sad panda geek girl.

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Re:Arrow of Time... by smittyoneeach · 2012-11-19 12:54 · Score: 0

Oh, many a shaft at random sent
Finds mark the archer little meant!
And many a word at random spoken
May soothe, or wound, a heart that's broken!
—Sir Walter Scott, Lord of the Isles

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Get thee glass eyes, and, like a scurvy politician, seem to see things thou dost not.--King Lear
Re:Arrow of Time... by Nyder · 2012-11-19 13:19 · Score: 3, Funny

Arrow of Time confirmed... Wheel of Time fans disappointed.
I've been disappointed since I realized the books were very engaging, exceptionally self-consistent, and... not only sexist but was a central component of the story. That sorta ruined it for me.
-- A sad panda geek girl.
yep, I noticed the women in the story were very mean to men...

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Be seeing you...
Re:Arrow of Time... by haruchai · 2012-11-19 13:22 · Score: 3, Funny

Really? A gay faggot? Is that anything like a straight heterosexual or just a very ecstatic bundle of twigs?

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Pain is merely failure leaving the body
Re:Arrow of Time... by socceroos · 2012-11-19 14:13 · Score: 2

Sexist? C'mon, seriously? Women were construed in a particular light were they? But, so were men? Granted, Robert had some funny views and an odd angle to things, but both sexes were firmly put in boxes. No need to get your knickers in a knot.
Re:Arrow of Time... by girlintraining · 2012-11-19 15:32 · Score: 1, Flamebait

, but both sexes were firmly put in boxes.
That, sir, is the definition of sexism.

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Re:Arrow of Time... by Anonymous Coward · 2012-11-19 15:39 · Score: 0, Funny

Oh... don't you worry your pretty little head...
Re:Arrow of Time... by socceroos · 2012-11-19 15:57 · Score: 1, Insightful

No, not quite - stereotyping/generalising is an element of sexism in many cases, but not the definition of it. I don't find, in any way, that the books elevate one sex over the other as more valuable.
Re:Arrow of Time... by fredprado · 2012-11-19 16:09 · Score: 5, Insightful

Hardly. Recognizing that there are differences between the sexes is common sense. Judging people's values and defining their roles solely by their sexes is sexism.

Women and men are not equal in everything. Trying to see equality in everything because it fits your notion of symmetry, fairness or whatever is self-delusion.
Re:Arrow of Time... by Anonymous Coward · 2012-11-19 19:33 · Score: 0

Times have changed since the 1980s when Robert Jordan started writing the series. In the current cycle, the world would be just as sexist, but Rand would be transgender, singing "I ain't got no taint no more"
Re:Arrow of Time... by silentcoder · 2012-11-19 20:19 · Score: 3, Insightful

>Hardly. Recognizing that there are differences between the sexes is common sense. Judging people's values and defining their roles solely by their sexes is sexism.
Those "differences" are provably superficial and purely cultural -as well proven by other cultures having radically different role expectations from sexes and both sexes playing into those different expectations with the same level as they do to the ones in ours.
Hell even in our own subcultures this view is greatly challenged. Consider for example the highly androgynous gender-roles of the metal and goth cultures - or the outright girly look of glam metal (which then ironically became equated with having the "guts to be glam" - the MOST masculine thing a man could do was to act feminine).
No my friend, the differences between the sexes exist only in the physical form.

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Unicode killed the ASCII-art *
Re:Arrow of Time... by Anonymous Coward · 2012-11-19 20:46 · Score: 0

What an stupid comment. What your example show is that we can paper over the differences, if we chose to. But we are different.And be LIKE being different. And not only between women and men, but from person to person.
It's the similarities that are cultural.
Re:Arrow of Time... by Anonymous Coward · 2012-11-19 22:52 · Score: 0

>Hardly. Recognizing that there are differences between the sexes is common sense. Judging people's values and defining their roles solely by their sexes is sexism.
Those "differences" are provably superficial and purely cultural -as well proven by other cultures having radically different role expectations from sexes and both sexes playing into those different expectations with the same level as they do to the ones in ours.
Hell even in our own subcultures this view is greatly challenged. Consider for example the highly androgynous gender-roles of the metal and goth cultures - or the outright girly look of glam metal (which then ironically became equated with having the "guts to be glam" - the MOST masculine thing a man could do was to act feminine).
Superficial?
BWAAA HAA HAAA
Call me when a dude has a baby.

No my friend, the differences between the sexes exist only in the physical form.
Bullshit.

Substantial research has sought to understand why more boys than girls excel in math. However, given the many dimensions in which girls outperform boys, it may seem misplaced to focus on the dimension in which girls are falling short. Why not examine the gender gap in verbal test scores where females outperform males?
...
So why do girls and boys differ in the likelihood that they excel in math? One argument is that boys have and develop superior spatial skills and that this gives them an advantage in math. This difference could have an evolutionary foundation, as male tasks such as hunting may have required greater spatial orientation than typical female tasks (Gaulin and Hoffman, 1988).
Re:Arrow of Time... by N!k0N · 2012-11-20 00:22 · Score: 1

Where's my sandwich?
Sorry, you don't have the proper permissions to run makesandwich.pl.
Re:Arrow of Time... by Anonymous Coward · 2012-11-20 01:29 · Score: 0

Scientific experiment is against you on this one. Girls will insinctively pick out "girly" toys (dolls, or something to nurture), whereas boys will pick out more masculine toys (tools or weapons, if you will) - outside of any cultural influence. If you claim that's not possible, well unfortunately for you the same is true when these same toys are given to baby monkeys.
There are distinct differences that are both physical and behavioural. Men and women are not biologically identical, and nor would anyone expect or want them to be. The problem isn't in ascribing difference; the problem is xenophobia (which affects both men and women); it's because many people equate "different" to "less than", or "not equal."
Although you're eager to point out some rather mainstream subcultures, you're still managing to equate "different" as a slur remark in a different context. You might want to think about that.
Re:Arrow of Time... by mdarksbane · 2012-11-20 01:36 · Score: 1

This is why it's useful to separate sex and gender - ie, what parts of "man" and "woman" are cultural creations and what parts are biological.
It's foolish to ignore either aspect. Watching my wife after she had our child, there are *definitely* strong biochemical and physical differences between men and women.
But this doesn't have much to do with the different gender roles everyone complains about in, say, Wheel of Time. Women don't nag because they're born to it - they nag because culture makes them to keepers and enforcers of civilized behavior.
That *said*... the vast majority of people, when raised in a society with strong gender roles, will generally exhibit them. So expecting women or men to consistently act like that society's image of women and men isn't sexist. Saying that they *must* act that way because biology is immutable is.
It's a complex, multi-variate system involving years of cultural and individual programming running on a meat machine that is also influenced by its base hardware and and its chemical sensors. No one should really claim that they completely understand it.
Re:Arrow of Time... by Anonymous Coward · 2012-11-20 01:39 · Score: 0

I don't get it. What's not physical about humans?
Re:Arrow of Time... by loufoque · 2012-11-20 01:42 · Score: 1

Don't underestimate the power of social conditioning.
Women and men are conditioned differently, and so, they are different.
Re:Arrow of Time... by silentcoder · 2012-11-20 02:07 · Score: 1

>It's foolish to ignore either aspect. Watching my wife after she had our child, there are *definitely* strong biochemical and physical differences between men and women.
I dispute both claims. And the idea that there is only 2 sexes, let alone only 2 genders. The evidence to the contrary is too strong.
For your own example: are you aware that newborns recognize their FATHER's voice BEFORE they recognize their mother's voice ?
If you see "different biochemical reactions" in her - I call that her being more committed to parenthood than you - a CULTURAL prescept.
In fact, there is a growing movement of men who use mental excercises and bonding-activities to stimulate male lactation (without liver damage) - that is to say massively increase their own progresterone production purely through emotional action (no supplements or such) in order to be able to breastfeed.
Even the most basic and simple biological version of "women's work" (that is to say: breastfeeding) is delineated ONLY by culture.
>That *said*... the vast majority of people, when raised in a society with strong gender roles, will generally exhibit them.
That's no more meaningful than saying "the vast majority of people when raised in a society that has a particular religion will generally embrace it" - it's still discriminatory and wrong to ASSUME that you are a Christian just because you speak English - as is expecting any particular behaviour on the basis of whether or not you have a penis.
>So expecting women or men to consistently act like that society's image of women and men isn't sexist.
Yes. It is. It's the very definition of sexism as it immediately precludes individual choice. Not to mention that even biologically the lines blur massively - there is no "men/women" divisor, rather a giant gray area with everybody somewhere in there. Some people have androgyn deficiencies and others have an excess and both are perfectly normal - even though it's absolutely irrational to expect two people with radically different levels of this hormone to behave in a similar manner just because they are in the same gender/sex box.
But I think "anticipating" may have been a less offensive term from you than "expecting" - not unsexist, but less so. Expecting implies expectation which has strong overtones of demand and authoritarianism.
>Saying that they *must* act that way because biology is immutable is.
As well.
>It's a complex, multi-variate system involving years of cultural and individual programming running on a meat machine that is also influenced by its base hardware and and its chemical sensors. No one should really claim that they completely understand it.
I agree with that- but then you disprove your own argument. The only SENSIBLE thing you can do in light of all that insecurity is to respect individual choice above all else and constantly guard yourself against making assumptions about people. The very definition of all discrimination is to make assumptions about individual nature based on group membership, when the group membership is involuntary (as in sex or race) the discrimination is far more severe.
Therefore the only way to NOT be a chauvinist, or a racist, or fill-in-bigot-of-choice-here is to assume NOTHING about an individual except what traits that individual has already exhibited. That is to say - actively make an effort to ignore group membership entirely - and get to know people as individuals.

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Unicode killed the ASCII-art *
Re:Arrow of Time... by fredprado · 2012-11-20 03:14 · Score: 2

That is what you want to believe. Unfortunately for you that is not the truth. Obviously there are cultural aspects that influence roles, but many of these cultural aspects are stemmed on physical differences and even in the absence of culture experiments have proven time and again that men's and women's instincts and thought processes have distinct differences. There is no motive to take offence on that as different is not necessarily better or worse.
Re:Arrow of Time... by Anonymous Coward · 2012-11-20 03:39 · Score: 0

Tell that to the brain structure changing hormones which are released/not released in different quantities in men and women.
Re:Arrow of Time... by mcgrew · 2012-11-20 04:08 · Score: 1

Those "differences" are provably superficial and purely cultural
No. Ever been married? A woman seems incapable of putting anything where they picked it up from, and every single married man I ever met concurs. "Where's the stratodoober, dear?"
"Just LOOK for it!" she says. It goes all the way back to hunter-gatherer societies, where women would pick fruits and nuts and berries, and men would hunt game. Evolutionary pressures made women adept at finding stationary things, and men adept at seeing movement. That is completely a brain thing.

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Re:Arrow of Time... by Anonymous Coward · 2012-11-20 04:44 · Score: 0

Ii am married. weve never had that conversation or anything like it. It only takes on counterexample to disprove a theory.
You see a trend and admit there may be rare exceptions. My experience is that the exceptions ARE the rule.
Group based assunptions are always false and the current "ancient evolutionary pressures" argument is just a modern version of "their brains overheat".
Re:Arrow of Time... by Anonymous Coward · 2012-11-20 12:20 · Score: 0

Basil Fawlty: I mean, where are the pens? I mean, what... Would you believe it! I mean, there are no pens here. I mean, this is supposed to be a hotel.
[sybil shakes a box]
Basil Fawlty: Well, what are they doing in there?
Sybil Fawlty: I put them there.
Basil Fawlty: Why?
Sybil Fawlty: Just sign there, Mr. Walt. Because you're always losing them, Basil.
Basil Fawlty: I am NOT always losing them. People TAKE them.
Sybil Fawlty: Well, they don't take them from me.
Basil Fawlty: They wouldn't dare. Well, I'm sorry I didn't guess that you'd suddenly done that after twelve years, dear. I'm afraid my psychic powers must be a little bit below par this morning. There we are.
Sybil Fawlty: Don't be silly, Basil. It's written there quite clearly on the top of the box.
Re:Arrow of Time... by Maritz · 2012-11-20 15:50 · Score: 1

In fact, there is a growing movement of men who use mental excercises and bonding-activities to stimulate male lactation (without liver damage) - that is to say massively increase their own progresterone production purely through emotional action (no supplements or such) in order to be able to breastfeed. Even the most basic and simple biological version of "women's work" (that is to say: breastfeeding) is delineated ONLY by culture.
A lot of what you say makes sense and I agree with the spirit of your post, but claiming that women breastfeeding is down to culture strikes me as mental. Is it cultural in pigs too? Rats? I had a quick look and saw this on Wiki (not the be all and end all but generally a decent jumping off point): "The phenomenon of successful human male breastfeeding has been credibly observed in several cases. However the cases are not sufficiently documented to allow distinguishing of possible pathologic galactorrhea."
It seems to me you need to be able to back this up, otherwise you're just weakening your general argument with this outlandish claim.

--
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Re:Arrow of Time... by silentcoder · 2012-11-20 17:53 · Score: 1

>A lot of what you say makes sense and I agree with the spirit of your post, but claiming that women breastfeeding is down to culture strikes me as mental
Well I never meant to suggest it was bad of culture, merely that it isn't unchangeable. The link between hormones and thoughts/emotions are well-known to work both ways (sufficiently so that some species can change sex at will) merely activating a fully functional set of glands that are already there seems fairly minor in comparison.
> Is it cultural in pigs too? Rats?
No. Pigs and Rats don't have cultures. Culture is an emergent phenomenon of intelligence - and vice versa. They are quite clever creatures but they have not developed culture, they don't yet have sufficiently advanced communication ability for that to happen.
However the mental ability that matters here is ANOTHER emergent phenomenon of high intelligence which, by all accounts, is equally absent from these species. The ability we call "free will".
Culture and Free Will are two contradictory sets of pressures - culture demands conformity, free will demands self-expression and individualism.
This is quite common in evolution - having two contradicting pressures battle until they reach a balance... and we got quite a few such battles happening in our heads.
Culture vs. free will is one of them.
Over time I believe free will has been winning - gaining small victories with every generation. Perhaps one day we'll recognize that culture is entirely superfluous (because it is) and that free will is much more important than we thought (because it is).
So that's the essence of my whole argument: individual free will can overcome both physical and cultural 'limitations' of ALL kinds - even the progesterone limitation on male lactation (apparently). You cannot make any assumptions on people based on either sex or gender because people do HAVE free will.
And that's before we even factor in individual personality - ... another force that works in conjunction with free will in most cases, but sometimes contradicts it.

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Unicode killed the ASCII-art *
Re:Arrow of Time... by silentcoder · 2012-11-20 20:08 · Score: 1

>There is no motive to take offence on that as different is not necessarily better or worse.
Yes. There is. There is a fundamentally offence whenever you ascribe to somebody a trait they have not exhibited and pretty much all the worst shit that happened in history can be shown to have been caused by exactly that.
It's no more true of sex/gender than it is of race. And the simple scientific fact is that the very IDEA of "men" and "women" are flawed, there are at least 26 variations on the XY chromosome that can chemically exist, of which at least 14 are viable and at least 8 have been observed in what we regard as normal, healthy humans.
That's 8 different sexes - at least.
On a surface examination those 8 are indistinguishable from either a 'man' or a 'woman' - yet their biochemistry is radically different. This is exactly why olympic sex tests have such difficulty finding a standard to settle on - because there isn't one in nature. The others are various forms hermaphrodite (which occurs in nature and therefore I reject the concept that they are NOT natural - we use surgery to make them one or the other more out of psychological need to shelter them than because it's medically required).
Many cultures on this planet have more than 2 gender's as well, in fact three or more is actually more common - western culture is basically unique in only having two! This is probably, at least in part, responsible for the embrace of androgyny and cross-gender identification of western subcultures.
The only valid traits to ascribe to a person are the traits that PERSON has exhibited. Anything else is conjecture and always far more likely to be false than true as it's based on a truly bad set of assumptions.
I stand by a firm belief that the experiments that supposedly show otherwise were flawed in numerous ways (scientists looking for evidence to support their theory instead of looking for evidence to disprove it, subjects acting on subconscious pressure to behave the way they sense the scientists expect them too etc.) as they simply don't match up to the known facts of human DNA and biology. We don't HAVE two sexes, we have at least 8 - that LOOKS like two on the surface.
And that's before you even consider individual deviation - the one thing we know for sure is that everybody deviates from even cultural norms in SOME ways. We can create lose categories of deviation (for example: the 'tomboy' stereotype) but they themselves show how flawed the idea of categorizing human behaviour is.
Take any two tomboys you know and compare how many interests they have in common and how many they don't. Which 'girly' things do one like and the other not? Which 'boy' things do they both like and which is liked by only one ?
Even for a well-known 'category' we quickly realise that we cannot make ANY assumptions. Two tomboys may both like to climb trees but only one likes toy trucks, or neither likes to climb trees ... even when you have two people both identifying with the same label you cannot make any predictions about them with ANY degree of accuracy.
Saying girls are like this and boys are like that is as meaningless as assuming ALL geeks love spiderman (how odd that many of the comic-book geeks I know despise him and consider Batman the epitomy of superheroes - I completely disagree and have always considered spiderman a better character). You can only even say "they both like superheroes" because we've both identified as such OURSELVES - many computer geeks don't like comic books or superheroes at all - yet it's considered a mainstay of their culture.
We can say that my born-culture (Afrikaans) likes to braai (that is cook meat over an open fire). But many people born into this culture don't like that, some are vegetarians and only like to braai vegetables, some hate the idea of cooking outdoors.
You can identify a cultural trait as existing, but you can NEVER ascribe it to any member of that culture until you have observed it in that PARTICULAR member.
The same goes for the cultural traits associated with gender and sex.

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Unicode killed the ASCII-art *
Re:Arrow of Time... by badkarmadayaccount · 2012-11-25 11:50 · Score: 1

sudo makesandwich.pl --peanut-butter=true --blueberry-jelly=true --extra-cinnamon=10

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Reading the Article Backwards... by Anonymous Coward · 2012-11-19 11:56 · Score: 2, Funny

Well, reading the article backwards still results in WTF?

Re:Reading the Article Backwards... by Anonymous Coward · 2012-11-19 12:22 · Score: 0

The person posting it didn't understand it, and therefore couldn't summarize it. Hence, its length.
Re:Reading the Article Backwards... by marcosdumay · 2012-11-19 12:24 · Score: 2

Whan read backwards it sounds like a foreign language and I can't understand a word. Thus, no change in that.
Now, seriously, the paper's abstract makes more sense than the article. And it is heavy in a jargon that I don't completely understand, while the article was arguably translated into normal english. What a bad translation!

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Re:Reading the Article Backwards... by avgjoe62 · 2012-11-19 12:54 · Score: 4, Funny

Funny - I read the article backward and I got that Paul is dead.

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Re:Reading the Article Backwards... by History's+Coming+To · 2012-11-19 15:16 · Score: 4, Informative

Here's my take on it:

In theory the basic mathematics of quantum theory is time-symmetric. You can write equations to describe particles x and y colliding to produce a and b, and those equations work perfectly well to describe particles a and b colliding to produce x and y. It's why Feynman diagrams are so useful, you can just flip the time dimension around and see something else described by the same maths.

The point of what these folks have done is to look very closely at one particular Feynman diagram, that of the B meson decay, and showing that it is not time symmetric in some way. So the flow of time is something extra on top of the basic quantum theory...that's fascinating.

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Re:Reading the Article Backwards... by Anonymous Coward · 2012-11-19 17:42 · Score: 0

Yes but WTF backwards is FTW .
Now that makes sense.
Re:Reading the Article Backwards... by Rakshasa-sensei · 2012-11-19 20:00 · Score: 2

Except the real point of the story is that since B mesons were not symmetrical for C and P, then finding out that it was symmetrical for T would mean that quantum theory isn't symmetrical.
Basically the particle needs to be non-symmetrical for all three of CPT, or none (which we know it isn't), else there is as you say 'something extra on top of the basic quantum theory'.
Re:Reading the Article Backwards... by Anonymous Coward · 2012-11-19 22:05 · Score: 0

Actually, they could also be symmetric for one, but not individually for the other two, as long as the other two combined are still symmetric.
For some time it was thought that while C and P are violated, CP were not, and T were not violated either, making CPT non-violated.
Re:Reading the Article Backwards... by Anonymous Coward · 2012-11-20 02:41 · Score: 0

I think your showing that, in your case, the arrow of time is highly terminal state ; )
Re:Reading the Article Backwards... by Anonymous Coward · 2012-11-20 05:31 · Score: 0

That was good!
Re:Reading the Article Backwards... by Anonymous Coward · 2012-11-20 07:28 · Score: 0

Haahahahaaaa!
Re:Reading the Article Backwards... by metaforest · 2012-11-20 20:23 · Score: 1

Look at a Rorschach diagram in a mirror.... and it seems to be the same... the pattern is reversible so says the math.
Reality says... not. even. close.
bub.
Color me shocked. /s

I Wish by NEDHead · 2012-11-19 11:56 · Score: 4, Funny

They would be more specific about the arrow of time. I get that they have confirmed it and all, but which direction is it pointing?

Re:I Wish by Anonymous Coward · 2012-11-19 11:59 · Score: 0

It's pointing along the time axis. Matter progress in one direction along the time axis and apparently antimatter progresses in the opposite direction.
Re:I Wish by fsck1nhippies · 2012-11-19 12:01 · Score: 1

Even better... How do you turn it around. I wanna win that bet on the world series.
Re:I Wish by Mitchell314 · 2012-11-19 12:04 · Score: 1, Funny

Slightly to the left, until I see the doctor again.

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I read TFA and all I got was this lousy cookie
Re:I Wish by girlintraining · 2012-11-19 12:09 · Score: 4, Informative

They would be more specific about the arrow of time. I get that they have confirmed it and all, but which direction is it pointing?
As I understand it (greatly simplified), time is a consequence of matter and energy interactions in space; They don't all happen at once though because of separation, and the distance (relative or absolute) between them is what creates time. That's why they call it 'spacetime'; The smallest unit of time then is the fastest change in quantum state possible. As time is a byproduct of matter and energy interactions, and couldn't exist without it, there's still the question of the "arrow of time". We perceive it to be always moving "forward", but there's no reason why the reaction A-B-C shouldn't go C-B-A as well, or instead.
If I understand this experiment correctly, what they're saying is "as well" is bogus. It's not just that it isn't observable, but that it just doesn't happen. No matter which way the reaction chain goes, there's no mirror reaction that goes unobservable. But perhaps someone who actually is a particle physicist could provide a layman explanation better than mine... I'll be honest: Most of what they do is beyond my grasp because they talk mostly in math and seem to eschew visualization or story explanation. -_-

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Re:I Wish by Anubis+IV · 2012-11-19 12:23 · Score: 2

Left if you're facing one way, but right if you're facing it from the other side. If you're facing it head-on or are behind it, you're holding your time wrong.
Re:I Wish by TexVex · 2012-11-19 12:29 · Score: 4, Interesting

The arrow of time is the reason why random bits of shrapnel and chemicals don't fly together and "un-detonate" to become hand grenades. In one direction of time, entropy in the universe always increases; in the other, it always decreases. The question is, why? If everything at the quantum level always worked the same way forwards as it does backwards, then entropy would be constant; the universe would be in some kind of steady state and nothing would matter because we wouldn't be here.

I think at this stage of research, it's more about finding clues than it is about trying to put them together into a coherent explanation. But if that's not true, I'd love to hear from someone who really knows this stuff..

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Re:I Wish by Anonymous Coward · 2012-11-19 12:45 · Score: 0

It's pointing to infinity and beyond
Re:I Wish by girlintraining · 2012-11-19 13:18 · Score: 2

The question is, why? If everything at the quantum level always worked the same way forwards as it does backwards, then entropy would be constant; the universe would be in some kind of steady state and nothing would matter because we wouldn't be here.
Maybe the universe was bored with the idea... :\

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Re:I Wish by Anonymous Coward · 2012-11-19 13:44 · Score: 5, Interesting

Take a video of some physical process and run it in reverse. At a macro level we humans can generally tell that the video is in reverse - tea cups break apart when hitting a floor, they don't spontaneously assemble and then fly off the floor. However, if you analyze such situations using the physics you learned in high school, there is no way to tell that the course of events has been reversed - statistically it's very unlikely that a tea cup would do that, but there is nothing physically impossible about it. So it appear that the laws of physics are the same if time was running in reverse yet to us humans it does not appear that things would be the same if time was running in reverse - because of entropy.
This is the problem of the arrow of time - how can we tell in a physical way which way time is running? Is there any way to distinguish going forward in time to going backward in time using just physical laws? You could say that entropy increases with time (the basis of how we humans can tell on a video whether it is running forward or backward), but that is only a statistical observation and it only holds because it just happens to be that our past has a very small amount of entropy compared to the high entropy situation that the universe will eventually reach. Increasing entropy is a consequence of an accident of what our past looks like and it is not a physical law in the strict sense we are looking for here. So entropy is not a good candidate. This research shows a way that you actually CAN tell if time is running in reverse. Though physicists still believe that there is a CPT symmetry, indicating that if you reverse time and also two other things, then there is no way to tell from physical laws that you did that.
Re:I Wish by Anonymous Coward · 2012-11-19 13:51 · Score: 2, Interesting

I don't really know this stuff that well. I did well in quantum computing, which covers the philosophy of the quantum postulates, but never really gets past baby level physics. That said, I've been thinking that maybe there's a bit more to flip than C, P, and T to get a better picture.
If you think of an explosion starting at time 0 and centered at [0,0,0], you start with density concentrated around that point and over time it spreads out from that point. Alternatively, starting at time t and going backwards to time 0, you see the dispersed mass flowing to concentrate at that point.
However, another picture is that starting at time 0, a lack of matter begins flowing into the area around the point [0,0,0]. Essentially this view looks at it like the negative space in a painting.
These two pictures aren't quite mirror images of each other, however with a coordinate transformation it might be possible to make them mirror images of each other. Something along the lines of mapping [0,0,0] to the point at infinity and continuously map the points surrounding the origin such that [1/d,1/d,1/d] goes to [d,d,d], basically turning space inside out around your origin point.
Re:I Wish by FrangoAssado · 2012-11-19 14:01 · Score: 5, Informative

If everything at the quantum level always worked the same way forwards as it does backwards, then entropy would be constant; the universe would be in some kind of steady state and nothing would matter because we wouldn't be here.
That's not true. "Everything at the quantum level always working the same way forwards and backwards" is completely consistent with the second law of thermodynamics ("entropy never decreases"), and completely consistent with the observable universe (barring CP violation). All that's necessary is that the universe started with very low entropy -- like, say, the Big Bang.
See for example this from this Arrow of Time FAQ (from cosmologist Sean Carroll):

The observed macroscopic irreversibility is not a consequence of the fundamental laws of physics, it's a consequence of the particular configuration in which the universe finds itself. In particular, the unusual low-entropy conditions in the very early universe, near the Big Bang. Understanding the arrow of time is a matter of understanding the origin of the universe.
Re:I Wish by msevior · 2012-11-19 14:02 · Score: 2, Informative

The arrow of time is the reason why random bits of shrapnel and chemicals don't fly together and "un-detonate" to become hand grenades. In one direction of time, entropy in the universe always increases; in the other, it always decreases. The question is, why?
The reason is very simple. Entropy is a measure of the probability of a particular outcome. The statement that "entropy increases" is simply the statement that the most probable thing to do happen is almost always the one that does happen. The "almost always" is a fantastically high probability. For example if I through a 1 cm cube of of aluminium at 26 C into a lake where the water is at a temperature of 25 C, there is something like a 10 ^-(10 ^10^23) chance that heat will from the lake into the aluminium cube and cause it's temperature to rise. If it did this the entropy of the Universe would decrease.
What this experiment observed is profound and extremely interesting. For some reason that isn't known, the Universe prefers that certain microscopic and reversible processes occur with a greater probability if time increases.
In other words there truly is a preferred direction to time which independent of tautology that the Universe is constantly evolving into a more probable state.
Actually this result is was first observed in K-mesons but this new result in B-mesons has much greater significance and confirms the previous observation.
Re:I Wish by evil+crash · 2012-11-19 14:19 · Score: 1

In the Northern Hemisphere time moves from left to right, in the Southern, it's right to left.

--
"Anyone who is capable of getting themselves made President should on no account be allowed to do the job."-THG
Re:I Wish by ceoyoyo · 2012-11-19 14:24 · Score: 4, Informative

The arrow of time refers to the fact that we perceive a difference between the past and the future: we remember the past, but not the future. That's explained adequately by noting that entropy tends to increase and the universe, for some reason, was in a low entropy state in the past.
What they've found is that, at least for b-mesons, going forward in time is different than going backward in time, presumably in addition to the rest of the universe accumulating entropy. It's as if there was a fundamental difference between moving "north" and moving "south" in empty space.
Re:I Wish by Black+Parrot · 2012-11-19 15:02 · Score: 3, Funny

which direction is it pointing?

Slightly to the left, until I see the doctor again.
Oh, great. Now time has a liberal bias too.

--
Sheesh, evil *and* a jerk. -- Jade
Re:I Wish by Anonymous Coward · 2012-11-19 15:58 · Score: 0

Going against the forward bias hard enough to let the magic smoke out of the subspace quantum diodes sounds like it might be really really bad. Most people tend to like the universe (because that's where we keep all our stuff), so let's not break it by trying too hard.
Re:I Wish by TheNinjaroach · 2012-11-19 16:11 · Score: 1

nothing would matter because we wouldn't be here.
Oh yes, there would still be matter. The universe is important with or without us.

--
I went to eat some animal crackers and the box said, "Do not eat if seal is broken." I opened the box and sure enough..
Re:I Wish by tyrione · 2012-11-19 16:27 · Score: 1

which direction is it pointing?

Slightly to the left, until I see the doctor again.
Oh, great. Now time has a liberal bias too.
From the Doctor's perspective it points to the right.
Re:I Wish by Nefarious+Wheel · 2012-11-19 16:55 · Score: 1

Time flies like an arrow, but Drosophilia Melanogastera like a banana.
Time is what keeps everything from happening at once; Space is what keeps everything from happening to you.
There are other suitable aphorisms I trust.

--
Do not mock my vision of impractical footwear
Re:I Wish by Artifakt · 2012-11-19 17:00 · Score: 4, Funny

From a Doctor's perspective, it may point to the right - from THE Doctor's perspective, time points anywhere he wants (unless it goes wibbly-wobbly).

--
Who is John Cabal?
Re:I Wish by msevior · 2012-11-19 20:54 · Score: 1

The arrow of time refers to the fact that we perceive a difference between the past and the future: we remember the past, but not the future. That's explained adequately by noting that entropy tends to increase and the universe, for some reason, was in a low entropy state in the past.
What they've found is that, at least for b-mesons, going forward in time is different than going backward in time, presumably in addition to the rest of the universe accumulating entropy. It's as if there was a fundamental difference between moving "north" and moving "south" in empty space.
Yes! Exactly!
Re:I Wish by ldobehardcore · 2012-11-19 21:42 · Score: 1

It's as if there was a fundamental difference between moving "north" and moving "south" in empty space.
Would a ratchet favoring one direction serve as some kind of applicable metaphor, or is it too crude to make any sense at all?
I understand well the entropy side of things, in that, since the universe started at a low entropy (an unlikely configuration) it moves towards high entropy over time (toward more common configurations.)
Would it be worthwhile to think of the T violation (in terms of visualization mind, not really understanding) perhaps like moving through barbs in 1 dimension? The "safe" direction and the "anti-safe" direction? I just chose barbs as an example, not because one direction is necessarily prohibited, but simply different from the opposite direction in terms of effects caused by direction reversal.

--
Hectice, baby, Mercator says hello to you
Re:I Wish by Anonymous Coward · 2012-11-19 23:02 · Score: 0

It's pointing up
Re:I Wish by Anonymous Coward · 2012-11-19 23:59 · Score: 0

Important to who?
Re:I Wish by ceoyoyo · 2012-11-20 01:38 · Score: 1

As far as the laws of physics are concerned, you can "move" either way in time and it doesn't make any difference (except for small violations like this one). It's just that you only remember going one way. For some reason we remember "back" in time, when entropy was lower.
Another poster had the best analogy I've heard: http://science.slashdot.org/comments.pl?sid=3261471&cid=42034773.
I'll paraphrase it: sitting in your chair you experience a distinct difference between "up" and "down." Things fall down, not up. You feel pulled down, not up. However, that difference is due only to special conditions at your current position in space. If you move to the other side of the world your up and down will be swapped. If you go far enough out in space, or into orbit, up and down disappear. Time is the same way except instead of a big mass on one side causing a gravity gradient in space it's the big bang on one side causing an entropy gradient in time.
Re:I Wish by NEDHead · 2012-11-20 03:04 · Score: 1

to 'whom'
Re:I Wish by mcgrew · 2012-11-20 07:34 · Score: 1

Time flies like an arrow, but Drosophilia Melanogastera like a banana.
Sorry, Sheldon, but your joke just doesn't work. The key is "flies" and the original only works spoken, or with "flys" misspelled.
How about "they say time flies when you're having fun, but why would I want to time flies?"

--
Free Martian Whores!
Re:I Wish by Anonymous Coward · 2012-11-20 12:20 · Score: 0

http://wiki.answers.com/Q/How_do_you_spell_flys
Re:I Wish by gwgwgw · 2012-11-20 16:26 · Score: 1

Thanks for the best description I can accept without immediate skepticism.

--
That was Zen, this is Tao
Re:I Wish by DiEx-15 · 2012-11-21 01:36 · Score: 1

It points up.

However you should seek medical attention immediately if it stays up for more than 4 hours.

Time by oodaloop · 2012-11-19 11:58 · Score: 3, Funny

Time flies like an arrow. Fruit flies like a banana.

That's all I've got to contribute. Carry on.

--
Tic-Tac-Toe, Global Thermonuclear War, and relationships all have the same winning move.

Re:Time by Anonymous Coward · 2012-11-19 12:12 · Score: 0

But bananas are boomerang shaped, so I guess we might all be in for a big "havent we been here before?" moment...
Re:Time by Anonymous Coward · 2012-11-19 12:14 · Score: 0

I thought fruit flies like beer.
Re:Time by InfiniteBlaze · 2012-11-19 12:19 · Score: 1

Time flies like an arrow. Fruit flies like a banana. That's all I've got to contribute. Carry on.
Fruit flies poorly without wings or an outside force acting upon it.
Re:Time by AwesomeMcgee · 2012-11-19 12:23 · Score: 1

Are you insulting bananas!?
Re:Time by statusbar · 2012-11-19 12:29 · Score: 1

No he is insulting fruit flies.

--
ipv6 is my vpn
Re:Time by sconeu · 2012-11-19 12:47 · Score: 2

No, but if someone attacks you with a banana, you'd better have a pointed stick ready.
Also, this "BaBar" experiment seems rather elephantine to me.

--
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
Re:Time by Anonymous Coward · 2012-11-19 12:47 · Score: 0

It's deja vu all over again.
Re:Time by Anonymous Coward · 2012-11-19 13:00 · Score: 0

Is there a "-1 anti-comedy" mod.
Re:Time by rossdee · 2012-11-19 13:00 · Score: 1

Boomerangs have an airfoil shape in cross section, bananas are just circular in cross section. its the lift generated by the airfoil shape, and gyroscopic forces that cause a boomerang to come back. I wonder how many millenea it took for the aborigines to refine that
The question remains - what does Newsweek fly like?
Re:Time by Longjmp · 2012-11-19 13:16 · Score: 1

Time flies like an arrow. Fruit flies like a banana.
Wow. I didn't know Groucho Marx was also a particle physicist ;)

--
There are fewer illiterates than people who can't read.
Re:Time by Sexy+Commando · 2012-11-19 13:22 · Score: 2

Yes. That was a banana...No one expects the banana!
Re:Time by Anonymous Coward · 2012-11-19 14:21 · Score: 0

It took me years to figure out the intended parsing of that sentence...
Re:Time by dudpixel · 2012-11-19 14:32 · Score: 1

Fruit flies like a banana.
Yes. Yes they do :)

--
This seemed like a reasonable sig at the time.
Re:Time by Anonymous Coward · 2012-11-19 19:08 · Score: 0

Time is an illusion. Lunch time doubly so.
Re:Time by Anonymous Coward · 2012-11-19 19:16 · Score: 0

Fruit flies like a banana. BaBar also like a banana.
Re:Time by deroby · 2012-11-19 23:09 · Score: 1

I was 'challenged' by a similar one when I was in school; could have taken me years to work it out by myself but (luckily) they explained it to me after about a week.
Time flies
you can't
only the slow ones.

--
If there is one thing to be learned on slashdot, it has to be sarcasm.
Re:Time by dak664 · 2012-11-20 02:57 · Score: 1

http://www.marx-brothers.org/info/quotes.htm
My favorite

Groucho: "That's in every contract, that's what you call a sanity clause."
Chico: "You can't a fool a me there ain't no sanity clause"
Re:Time by mcgrew · 2012-11-20 09:44 · Score: 1

Holy crap, never have so many slashdotter been wooshed over a silly misspelling. Fruit flies like a bananna is false, fruit flys like a bananna is true.

--
Free Martian Whores!
Re:Time by oodaloop · 2012-11-20 11:22 · Score: 1

Clearly, the all-time best quote from a Marx Brothers movie (from your link) is:

"honk honk"

Harpo Marx

--
Tic-Tac-Toe, Global Thermonuclear War, and relationships all have the same winning move.
Re:Time by jedwidz · 2012-11-20 12:39 · Score: 1

And dictionary flies like a... DUCK!
WOOSH!

Yes ... by Kaz+Kylheku · 2012-11-19 12:04 · Score: 1

Time does not run the same way backward as it does forward. It, like, runs forward and does not run backward.

Re:Yes ... by AwesomeMcgee · 2012-11-19 12:33 · Score: 1

It's much more careful going backwards, it walks instead of running, good thing too, wouldn't want time to trip and fall.
Re:Yes ... by Mateorabi · 2012-11-19 15:12 · Score: 2

Actually, it's more like a big blob of wibbley wobbley, timey wimey.... stuff.

--
"You saved 1968." - Ms. Valerie Pringle to the crew of Apollo 8

Inverted Truth by KlomDark · 2012-11-19 12:06 · Score: 0

This is all a giant mix of hogwash and bullshit intended to discredit (amongst only the easily-impressed, low-information scientists of the validity of Doctor Emmett Brown's proven research.

Re:Inverted Truth by Anonymous Coward · 2012-11-19 12:26 · Score: 0, Insightful

There is an unmatched parenthesis in your comment. Somehow I think the missing parenthesis is necessary to help people parse the sentence correctly.
Re:Inverted Truth by Anonymous Coward · 2012-11-19 12:40 · Score: 1

) time travel. (Please ignore everything between the parenthesis, thank you)
Re:Inverted Truth by Ultra64 · 2012-11-19 13:49 · Score: 1

"(Please ignore everything between the parenthesis, thank you)"
Um
Re:Inverted Truth by reboot246 · 2012-11-19 15:14 · Score: 1

It's very hard to write something inside of a parenthesis. The plural of 'parenthesis' is 'parentheses'.

wait what? by Trunksword · 2012-11-19 12:11 · Score: 1

After reading the whole thing, I still don't understand a thing it said. Maybe I'm illiterate.

Re:wait what? by Baloroth · 2012-11-19 13:20 · Score: 5, Informative

Let me explain. Most reactions are time-reversible. (Sort of) example: oxygen and hydrogen can combine to form water and release energy, but you can put energy back into the system to get hydrogen and oxygen back out again (thermodynamics states you will always lose some energy in this process, however, no matter how efficiently you conduct the H+O->water->H+O process).which indicates time is not perfectly reversible, but doesn't explain why). At the subatomic level, however, some similar (vaguely similar, anyways) reactions cannot be reversed, or don't reverse in the same way. In this case, they studied a meson that spontaneously changes from matter to antimatter and back (don't ask). If time reversibility held true for them, the probability of matter->antimatter would be the same as the probability of antimatter-> matter. It was not, by a very very very very significant margin (14 sigma, or a 1 in 10^43 chance this was seen by accident). Note this may also help to explain why matter is more prevalent than anti-matter in our universe.

--
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
Re:wait what? by Anonymous Coward · 2012-11-19 15:00 · Score: 0

THANK YOU for your easy to understand explanation.
Re:wait what? by Black+Parrot · 2012-11-19 15:04 · Score: 2

But what does it all *mean*?
Should I buy a Tesla, or give everything I own to the poor and go stand on the mountaintop?

--
Sheesh, evil *and* a jerk. -- Jade
Re:wait what? by Nefarious+Wheel · 2012-11-19 16:59 · Score: 2

Yes, you should.

--
Do not mock my vision of impractical footwear
Re:wait what? by Trunksword · 2012-11-20 12:51 · Score: 1

Thank you, makes better sense now.

Damn it, where is my car analogy! by Derekloffin · 2012-11-19 12:12 · Score: 1

I'm totally lost. So they tracked the decay of particle in the past by having them entangled with with particles from the future? Sorry, my feeble little brain has obviously reached its limit.

Re:Damn it, where is my car analogy! by Kergan · 2012-11-19 12:18 · Score: 1

Same. I hope some quantum physicist will chime to mention how one can observe time going "backwards" and how this extremely high level of statistical significance isn't another way of saying that they can't.
Re:Damn it, where is my car analogy! by edxwelch · 2012-11-19 12:42 · Score: 1

Ok: A Ford Fiesta made entirely of anti matter would travel backwards in time and turn left when you wanted to go right.
Re:Damn it, where is my car analogy! by ceoyoyo · 2012-11-19 14:29 · Score: 1

No, they watched particles "decaying" in one way versus ones "decaying" in the opposite direction. The second process would be identical to the first if you were running time backwards.
Re:Damn it, where is my car analogy! by Black+Parrot · 2012-11-19 15:05 · Score: 1

This is Slashdot. You're supposed to demand a flying car analogy.

--
Sheesh, evil *and* a jerk. -- Jade

Dear Slashdot: by Anonymous Coward · 2012-11-19 12:18 · Score: 4, Insightful

Bet you wish you had unicode now, eh?

Re:Dear Slashdot: by Anonymous Coward · 2012-11-19 14:47 · Score: 0

Too bad the TFA used the same moronic typesetting, not a /. issue.

noy really the arrow of time by bcrowell · 2012-11-19 12:18 · Score: 3, Interesting

I wouldn't really describe this as confirming the arrow of time.

The really powerful arrow of time is the thermodynamic one. The second law of thermodynamics says that entropy always increases. This thermodynamic arrow is essentially the same arrow as the psychological one, which allows us to remember the past but not the future, and all the other ones we see in nature, such as the laws of black hole thermodynamics, which say that the area of a black hole's event horizon always grows with time. This group of time-arrows, which are all essentially the same time-arrow, appear to occur because the big bang was fine-tuned to be extremely low in entropy, with its gravitational-wave degrees of freedom inactive. Nobody knows why we had a low-entropy big bang, when a random choice of initial conditions would be overwhelmingly more likely to produce a maximum-entropy one. (In particular, inflation doesn't explain it. Also, statistical mechanics doesn't explain it, because to produce the second law from statistical mechanics, you need to assume a low-entropy initial state.)

This paper is about an arrow of time that is obscure and completely unrelated to the others. It has to do with the weak nuclear force. Unlike the others, it has essentially no effect on the world we see around us.

--
Find free books.

Re:noy really the arrow of time by inputdev · 2012-11-19 12:57 · Score: 1

I wouldn't really describe this as confirming the arrow of time.
The really powerful arrow of time is the thermodynamic one. The second law of thermodynamics says that entropy always increases. This thermodynamic arrow is essentially the same arrow as the psychological one, which allows us to remember the past but not the future, and all the other ones we see in nature, such as the laws of black hole thermodynamics, which say that the area of a black hole's event horizon always grows with time. This group of time-arrows, which are all essentially the same time-arrow, appear to occur because the big bang was fine-tuned to be extremely low in entropy, with its gravitational-wave degrees of freedom inactive. Nobody knows why we had a low-entropy big bang, when a random choice of initial conditions would be overwhelmingly more likely to produce a maximum-entropy one. (In particular, inflation doesn't explain it. Also, statistical mechanics doesn't explain it, because to produce the second law from statistical mechanics, you need to assume a low-entropy initial state.)
Would cooling from expansion and corresponding symmetry breaking explain it? Why would the big bang have to be a low-entropy state in any global sense (and what difference would that even make?), wouldn't entropy still be able to increase from any initial point?

This paper is about an arrow of time that is obscure and completely unrelated to the others. It has to do with the weak nuclear force. Unlike the others, it has essentially no effect on the world we see around us.
Is it possible that this observation is related to an increase of entropy that is not properly described by the particles in the model?
Re:noy really the arrow of time by Anonymous Coward · 2012-11-19 13:52 · Score: 0

That things started at low entropy is an accident of facts about the infinitesimal (compared to infinity) amount of time at the very beginning of our universe. In terms of the infinite time that the universe will exist, it will immediately reach a high entropy state and the arrow of time that you are referring to will cease to be relevant. Yet this finding will persist. Although, since they still believe that the CPT symmetry exists, this isn't actually an arrow of time at all - there still appears to be no arrow of time in physics at all, as I understand it, apart from this quaint situation we are in that will immediately cease to be the case on the universe's time scale.
Re:noy really the arrow of time by shoor · 2012-11-19 14:00 · Score: 1

Nobody knows why we had a low-entropy big bang, when a random choice of initial conditions would be overwhelmingly more likely to produce a maximum-entropy one
The explanation that I see is that there might be a 'multiverse', many big bangs, most of which would not produce a universe that could support life. Therefore, we're here because this is the one in a skadzillion that could and did produce life intelligent enough to wonder about this stuff. It's a plausible explanation to me, but that doesn't mean it's correct of course.
I'm still looking for a really good explanation of what the article is about. The 'arrow of time' I'm familiar with, and which has been mentioned in other posts, is the entropic one. There are so many ways for things to get disarrayed as opposed to the extremely few for them to get re-arrayed, that we never see it happen, nevert see things like objects getting hotter than ambient temperature without a source of heat or things randomly assembling themselves into some recognizable order.

--
In theory, theory and practice are the same; in practice they're different. (Yogi Berra & A. Einstein)
Re:noy really the arrow of time by Anonymous Coward · 2012-11-19 14:01 · Score: 0

We don't currently have an explanation of entropy. We have a lot of observation, but no good sound reason for it.
Re:noy really the arrow of time by ceoyoyo · 2012-11-19 14:31 · Score: 1

"it has essentially no effect on the world we see around us."
Well, except for being necessary for CP violation, which in turn is the only way we have of explaining why there isn't much antimatter around.
So it does explain why the planet is here and doesn't experience nuclear-style detonations many times an hour as antimatter grains of dust hit the atmosphere. But other than that no effect on the world around us.
Re:noy really the arrow of time by Anonymous Coward · 2012-11-19 20:26 · Score: 0

But this doesn't explain the arrow of time either. Loschmidt's paradox kind of messes it up.
Re:noy really the arrow of time by mattr · 2012-11-20 03:14 · Score: 1

Could it just be that all universes exist but since virtually all the other kinds from ours don't produce life, the odds are very high that we exist in one with a "tuned" big bang?
Kind of a cross between the anthropic principle and that recent theory I remember saying that all universes based on consistent logics exist..
Re:noy really the arrow of time by bcrowell · 2012-11-20 05:24 · Score: 1

I think there are problems with using the anthropic principle for this. One is that the observers would be astronomically more likely to be Boltzmann brains than observers like us living in an entire universe that is not at maximum entropy.

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Find free books.

Four years? by DaveyJJ · 2012-11-19 12:19 · Score: 1

Well that took enough time, didn't it.

--
DaveyJJ

Re:Four years? by AwesomeMcgee · 2012-11-19 12:25 · Score: 1

They just needed a significant enough sample size for their time experiment to be proved out, like four years.
Re:Four years? by Nidi62 · 2012-11-19 12:40 · Score: 1

It actually took 6 years, but since they kept turning back time it really only took 4.

--
The only thing necessary for evil to triumph is for it to be pitted against a slightly greater evil
Re:Four years? by rjgill · 2012-11-20 06:06 · Score: 1

Actually, it took 5 years, because that's all we've got. Yes, 5 years. My brain hurts a lot.

Explanation? by Anonymous Coward · 2012-11-19 12:23 · Score: 0

Could some kind particle physicist out there please provide an explanation of this and why it is important.

arXiv link by Baron+Eekman · 2012-11-19 12:50 · Score: 5, Informative

Come on people, how hard is it to include the arXiv link? Just google the title, it's usually the first hit.
http://arxiv.org/abs/1207.5832

Re:arXiv link by Janek+Kozicki · 2012-11-20 03:55 · Score: 1

Thanks

--
# #\ @ ? Colonize Mars #

WRT: The Arrow of Time... by VortexCortex · 2012-11-19 13:10 · Score: 0

Confusyah say: Time flies like an arrow, but fruit flies like a banana.

What this means by SoftwareArtist · 2012-11-19 13:20 · Score: 5, Informative

The summary is a bit confusing if you don't know what it's talking about. The title is even worse, since it implies the exact opposite of what it actually means. Let me try to explain it.

First: physicists believe that the "arrow of time" isn't a fundamental property of the laws of nature. There's no fundamental difference between "forward in time" and "backward in time". The laws of physics operate identically in both directions. So why do those directions seem so different? Why do objects fall down but not up? Why can you make an egg into an omelet, but not an omelet back into an egg? Why can you remember the past, but not the future? This turns out to be a property of our local region of spacetime. More precisely, we live very close (a mere 13.5 billion years or so) away from a point of incredibly low entropy (known as "the big bang"), and that creates an entropy gradient throughout our region of spacetime. What we call "forward in time" simply means "the direction of increasing entropy", or more simply, "away from the big bang".

A good analogy (not involving a car - sorry!) is the direction "down". It seems obvious to you that one particular direction in space is fundamentally different from all other directions. Objects fall down. They don't fall in any other direction. Yet to person on the other side of the earth, the direction they call "down" is completely different from the direction you call "down". That's because the "arrow of gravity" is not a fundamental property of the laws of nature, just a property of our local region of space. "Down" means "toward the center of the earth." In the same way, "forward in time" means "away from the big bang".

Second: what I just said swept a few details under the rug. You see, the true symmetry is not time reversal (which would imply that simply reversing the direction of time would leave all laws of physics unchanged), but a slightly more complicated symmetry called CPT invariance. That stands for Charge, Parity, and Time. It says that if you multiply the charge of every particle by -1 (so positive charges become negative and negative become positive), flip space as if in a mirror so that your left and right sides are reversed (a "parity inversion"), and reverse the direction of time, then all the laws of physics are left unchanged.

Scientists had previously observed a violation of CP. That is, swapping only charge and parity is not an exact symmetry of the universe. If CPT is an exact symmetry (which scientists generally believe), that implies that T is not - changing only the direction of time without also swapping charge and parity should change the laws of physics. But testing that experimentally turned out to be very hard to do. Well, they've finally done it. And the results are exactly what people expected: it appears that CPT really is an exact symmetry of the universe.

--
"I'm too busy to research this and form an educated opinion, but I do have time to tell everyone my uninformed opinion."

Re:What this means by patchouly · 2012-11-19 13:36 · Score: 0

Great description! Thanks for taking the time to write this out. If I had any mod points, I'd be giving one to you!
Re:What this means by PiSkyHi · 2012-11-19 15:31 · Score: 0

I don't think the reversing the syllogisms holds in this example. It is not sufficient to say that because T is violation that T would not be in violation if the universe were flipped and all CPT were now opposites. Just managing to show that things do not reverse equally in this universe, does not mean that by inverting everything, you also invert false to true.
I think you have misunderstood the implications of this finding. Just like gravity waves and their observation (or lack of), I think it only takes a small philosophical thought experiment to realise that there are problems with the questions being asked here and so the results alone will only serve to confuse.
For a start, let's assume that time is a dimension - this is an assumption that most physicists hold dear, some do not.
In this circumstance, the arrow of time appears arbitrary since positions in a spatial dimension appear arbitrary - it could this far along and a sequence of actions moved it in this direction, reversing all the actions perfectly moves everything the other way.
Of course, even if this were definitely true, you would still be faced with the dual direction problem - i.e. it looks like if time is a dimension, then it runs the same way forward as backward - as long as actions are reversible. This is just another way to say that time itself is static, the chosen direction itself is arbitrary and one could say that in a inverted universe my reverse is your forward. What I'm really saying here is that if time is a dimension, then the real problem is having a universe where time runs both forwards and backwards in different regions of space and that it would be possible to observe one from the other. This violates relativity.
So, if time were not a dimension, merely a product of components of the universe being able to interact consistently with other components of the universe (i.e. for this to happen, you need causality and change), then it would appear to have a direction to observers too small or slow, but this would be an illusion because the observer can not exist outside of the realm being observed. It's like a physicist is doing a thought experiment without realising he doesn't actually exist outside of the realm he is imagining to be our universe.
Time is a process - Time has no direction at all because it is the process of change that allows observers to do anything at all, imagining it running another direction is actually happening in this universe. Time is the result of a universe struggling with a paradox of it being one solid indivisible thing, or a multitude of things that appear to interact. If it contains components, they require time to observe each other with consistency, being the result of the causality required to keep things consistent. If there were no relativity, the universe would have no discernible objects and its only consistency would be to remain a single, solid unchangeable, unobservable thing.
so CPT invariance implies that the universe is the same thing, just being viewed differently - you still can't run it forwards and backwards in different regions of space and this whole thing of it being viewed differently is just a thought in someone's very real head that also cannot run time differently - it cannot be "viewed" from outside at all. I nearly said you can't run time forwards and backwards in the same universe, at the same time! But of course, the absurdity of that just illustrates that some questions are just improperly formed and do not have meaningful answers because the questions themselves are self-inconsistent and meaningless.
Re:What this means by shadowofwind · 2012-11-19 17:30 · Score: 1

Off topic comment and question:
Physicists tend not to speculate about things that can't be rigorously pinned down with math or in a lab experiment. At least not publicly. Non-physicists generally don't know what they're talking about when they discuss physics. And all people tend to overlook or dismiss experiential data points that lie outside of their existing mental models of how the world works - they don't know what to do with it.
Attempts I've seen to explain or lend credibility to religious or paranormal phenomena in terms of 'modern physics' are clearly mostly nonsense. I have unusual but recurring and objectively verifiable experiences that I've been trying to make sense of, and I'd sort of concluded that they are completely outside of what can be accounted for by existing scientific theories. More recently I'm not so sure though. If this doesn't sound too vague and flaky to you, and you're interested in kicking around some ideas offline, I'm interested in doing that.
Re:What this means by Anonymous Coward · 2012-11-19 17:51 · Score: 0

Perhaps I'm a bit thick, but what do physicists mean exactly when they say "symmetry"?
Re:What this means by PiSkyHi · 2012-11-19 17:56 · Score: 1

I think you raise a good point that physicists tend to follow only math or lab results, this leaves out the other important aspect of physics, philosophy. So many people think they sit in opposition, physicists should treat philosophy as some kind of irrational mysticism. Truth is, its very easy to miss logical fallacies in experiment proposals because you might think that since anything is possible, any experiment is a valid one. If you include philosophy into the design of a physics experiment, you get to analyse the self-consistency of the proposal before putting it to the test. You might say, well, what if the physics defies the philosophy, well they do go hand in hand and a very expensive experiment should be made to pass both tests, starting with the relatively inexpensive, deep self-consistent logical analysis. What if time could run backwards ? Relative to what ? to where you are now ? so time can run both ways in space and be observed in time ? whose time - the reverse or the forward time we observe in ? so the fundamental operations could go either way - that's still not time in a different direction, since if they did go both ways in the same universe, causality would be floored and relativity would fail, leading to an inconsistent reality. Conclusion without any need for experiments: If you believe reality is consistent, time does not travel in 2 directions in 1 universe.
Re:What this means by khallow · 2012-11-19 19:25 · Score: 2

For a start, let's assume that time is a dimension
We don't have to assume it. We can observe the dimension of time with a clock. If we start moving the clock a bit then we change the axis which the clock is measuring. This indicates that the dimension of time exists, but isn't unique due to how we can change frame of reference.

it could this far along and a sequence of actions moved it in this direction, reversing all the actions perfectly moves everything the other way.
Sequence of actions isn't well defined. It is quite possible to observe different sequences of events based on where you are and how fast you are moving. One event follows another only if the second event is in the future cone of the first event (assuming events are points in space-time). This is equivalent to the first event being in the past cone of the second event.

Of course, even if this were definitely true, you would still be faced with the dual direction problem - i.e. it looks like if time is a dimension, then it runs the same way forward as backward - as long as actions are reversible. This is just another way to say that time itself is static
No, it's not. Something is static if it doesn't change with respect to time. Any parameter changes with respect to itself at rate 1.

What I'm really saying here is that if time is a dimension, then the real problem is having a universe where time runs both forwards and backwards in different regions of space and that it would be possible to observe one from the other.

This isn't at all a problem. After all, we can already observe in every unit of space, time moving forward or backwards as we see it. The trick is to have a consistent change of coordinates between the differing viewpoints. They are different frames of reference for the same space and every frame of reference has this consistent transformation to another frame of reference for the same space (so changing the direction of time is not even a unique transformation of the space, but part of a much larger set of transformations).

Every physical property dependent on space-time coordinates can thus be transformed via change of coordinates.

The sequence of events is not a neat linear ordering with everything happening in a strict sequence, but a sort of "partial ordering" where somethings happen after others, while others are incomparable either because they could happen before or after, depending on your frame of reference, or because they'll never affect each others' future timeline (say due to an expanding universe stretching space infinitely much between them).

Finally, there are words you use, such as "static", "dynamic", and "interact" that require time to exist in order to make sense. So saying

Time is the result of a universe struggling with a paradox of it being one solid indivisible thing, or a multitude of things that appear to interact.
You can't "appear to interact" without some sort of time coordinate along which the interaction occurs.
Re:What this means by khallow · 2012-11-19 19:32 · Score: 1

Where philosophy intersects with physics, it is called "physics".

Conclusion without any need for experiments: If you believe reality is consistent, time does not travel in 2 directions in 1 universe.
We've never managed to go without need for experiments. It's worth noting here that there is an odd sort of higher order of empiricism over general philosophy. One can observe systems which model philosophical arguments. We are such. But there aren't purely philosophical arguments which say concrete things about reality. One needs empirical priors.
Re:What this means by PiSkyHi · 2012-11-19 19:44 · Score: 1

> We can observe the dimension of time with a clock.
Please, I think you are both too small and too slow to see it for what it really is when you look at a clock. You assume it is a dimension as we all do, since for our scale of things, this works pretty well.
> No, it's not. Something is static if it doesn't change with respect to time. Any parameter changes with respect to itself at rate 1.
Again, please I refer to time "itself" to try and catch you before you trip. When I say in this circumstance, time "itself" is static, I mean to say that if it can be reversed along with physical actions and you get back what you started with, then it is independent and unchanging, predetermined and all that that implies - essentially, static.
> This isn't at all a problem. After all, we can already observe in every unit of space, time moving forward or backwards as we see it.
No. I'll stop here. This is just wrong, so I won't go any further with it.
Re:What this means by PiSkyHi · 2012-11-19 19:49 · Score: 1

> Where philosophy intersects with physics, it is called "physics".
And yet, so many physicists have no idea how important self-consistency is in their physics.
> We've never managed to go without need for experiments.
Well, I never made such claim.
Also, Chicken or the egg, physics and philosophy, only a physicist ignoring self-consistency would bother trying to collapse this.
Re:What this means by Anonymous Coward · 2012-11-19 20:36 · Score: 0

This is an awesome post which answers a question I had about physics for 20 years.
This turns out to be a property of our local region of spacetime. More precisely, we live very close (a mere 13.5 billion years or so) away from a point of incredibly low entropy (known as "the big bang"), and that creates an entropy gradient throughout our region of spacetime. What we call "forward in time" simply means "the direction of increasing entropy", or more simply, "away from the big bang".
So, do you have a reference/citation for this? Where I can read more detail? Is this Someone's Theorem?
And the results are exactly what people expected: it appears that CPT really is an exact symmetry of the universe.
Well AIUI they haven't really shown that CPT is *exact*, just that (as expected) T symmetry alone is wrong.
Re:What this means by Anonymous Coward · 2012-11-19 20:40 · Score: 0

Question: specifically how does having regions of space where observers see time in opposite senses violate relativity? I can see how it violates causality, but not relativity per se. Which supporting experiment of relativity would prove that this can't happen?
Re:What this means by trifish · 2012-11-19 20:55 · Score: 1

> Sequence of actions isn't well defined
It actually is very well defined. The light cone is not about sequence of events but sequence of IMAGES of the events you see. The actual order of events in which they actually happen is constant for any observer. The fact that they don't see its image yet doesn't mean it didn't happen yet.
Re:What this means by Anonymous Coward · 2012-11-19 22:30 · Score: 0

You got it backwards: The basic assumption is that CPT is strictly conserved. This is part of the fundamental theories, and if we ever found a CPT violation, it would mean that our fundamental theories have to be revised.
Now we already had observed CP violation. If CPT holds, this means T must be violated, too, because if T wasn't violated, CP and CPT would be equivalent (since the T just wouldn't change anything). That is, if our theories are correct, there must be T violation. This experiment was a test of that, and since it found the T violation, it confirms (note: confirms, not proves) the theories, and in particular the CPT symmetry.
There's no reversal of syllogism involved, and nobody claims that CPT has been proved by this experiment (indeed, experiment never prove something). However it doesn't give us a reason not to assume CPT, which we do assume because the theories built on that assumptions happen to work very well.
Re:What this means by MasterPatricko · 2012-11-19 23:37 · Score: 2

A symmetry under X means the system under test is unchanged (ie the same physical laws work, your predictions are still correct) when you do X.
A simple example is the symmetry under spatial translation -- if your experiment still behaves the same way if it's moved a meter to the left, it has "spatial translational symmetry". This symmetry isn't exactly true on the surface of the earth because of variations in the gravitational field etc., but on a small scale for lab experiments it's true, and in deep space it's certainly true. Another example is symmetry under spatial rotation -- your experiment doesn't care whether you face it north or east.
By a very cool bit of maths called Noether's Theorem, you can show that for every symmetry that a system has, there is an associated conserved quantity. So systems with spatial translation symmetry will show conservation of momentum. Systems with time translation symmetry exhibit conservation of energy -- within that system, you can't create or destroy energy. Rotational symmetry results in conservation of angular momentum.
https://en.wikipedia.org/wiki/Symmetry_(physics)
Much of modern physics is built around identifying the symmetries that the universe (or parts of the universe) obeys, the associated conserved quantities, and what happens when those symmetries are broken -- for example the maths leading to the Higgs boson. Currently we believe the universe overall obeys C(harge) P(arity) T(ime) symmetry, that is if you change matter for antimatter, flip everything spatially (as in a mirror), and reverse the direction of time, everything would be the same. This recent experiment shows that time symmetry by itself is not obeyed -- if you only reverse the direction of time, this particular particle collision is not the same.

--
I'd tell a UDP joke, but you may not get it. I'd tell a TCP joke, but I'd have to keep repeating it until you got it.
Re:What this means by MistrX · 2012-11-20 01:18 · Score: 1

Question:
So if CPT is the true symmetry of the universe, then doesn't that solve the matter/antimatter problem (the problem that we observe more matter then antimatter)?
Say that the Big bang didn't create 'just' our universe, but a second that is a complete CPT reversal from ours. That universe would have the same kind of physics but with the arrow of time reversed relative to ours and would consist primarily of antimatter with minute quantities of matter. And 'left' probably being our universe equivalent of 'right'.
To my understanding this would be the true symmetry of our universe then. There is not 1 (ours) but 2.
Re:What this means by rufty_tufty · 2012-11-20 01:39 · Score: 1

If you believe reality is consistent, time does not travel in 2 directions in 1 universe.
Actually you raise an interesting point. If there are no CPT violations then time could travel in both directions and we would be none the wiser.
Imagine the last few seconds I just experienced suddenly ran backwards - without CPT violations I would be back at the same initial starting conditions and then time goes forwards again and I'd have exactly the same outcome. Time could move forwards and backwards totally randomly and we would never be any wiser.
With CPT violations of course that could not happen.
What any of this means for the randomness of quantum mechanics I have no idea - especially with the disproval of the hidden variables theory.

--
"The weirdest thing about a mind, is that every answer that you find, is the basis of a brand new cliche" -
Re:What this means by khallow · 2012-11-20 02:57 · Score: 1

Please, I think you are both too small and too slow to see it for what it really is when you look at a clock.
Not at all. Watching a clock is something everyone can do. Evidence trumps philosophy.

You assume it is a dimension as we all do, since for our scale of things, this works pretty well.
And I'm right too. And yes, you may be right as well about smaller (Planck) scales not having a time dimension.

When I say in this circumstance, time "itself" is static, I mean to say that if it can be reversed along with physical actions and you get back what you started with, then it is independent and unchanging
With respect to what? Static implies constant with respect to time which is itself. But it's not. Predetermination or its absence would not change that.

This isn't at all a problem. After all, we can already observe in every unit of space, time moving forward or backwards as we see it.
No. I'll stop here. This is just wrong, so I won't go any further with it.
Why stop here? There may be some part of the universe which doesn't have a time coordinate, but we don't observe it. What we do observe can have time moving forward or backwards. We just have to make a change of coordinates (or when making any other change of frame of reference) on all physical observables in the system, such as swapping sign of charge and parity when we flip the direction of time (in order to preserve CPT).

Your basic objections on time are addressed by the change of coordinates procedure. It provides consistency across arbitrary viewpoints of the universe.
Re:What this means by khallow · 2012-11-20 03:02 · Score: 1

The actual order of events in which they actually happen is constant for any observer.

But the order of events is subjective, dependent on where the observer is, and how they are moving with respect to those events. That's what makes it ill-defined.

The fact that they don't see its image yet doesn't mean it didn't happen yet.
Nor does it mean that it did happen yet. Only when they observe the event, can one say that it did happen.
Re:What this means by khallow · 2012-11-20 03:29 · Score: 1

And yet, so many physicists have no idea how important self-consistency is in their physics.
You base this on what? Your claims about assumptions on time are addressed both by actual observation of the dimension of time (confirming the validity of the space-time model at the scale in which it is used) and by the procedure of change of coordinates (which provides the consistency you claim is missing from discussion of time).
Re:What this means by PiSkyHi · 2012-11-20 04:01 · Score: 1

See GM, Euclidean space is just an approximation - because at least we can use some of math then.
Re:What this means by trifish · 2012-11-20 04:11 · Score: 1

This is classical fallacy resulting if you "think too much" within the principles of relativity. Think about what you wrote. It is plainly wrong.
The fact that you don't see the light of an event doesn't mean it didn't happen. It already happened. It is absolute. What is relative is when you will see the light of the event. That's all. The event itself is not relative.
Re:What this means by khallow · 2012-11-20 04:26 · Score: 2

The fact that you don't see the light of an event doesn't mean it didn't happen.
As I note, you aren't in a situation to determine whether an event happened or not until that event passes into your past light cone. A big point to make at this time is that there are places and frames of reference where your current state and the event can be observed to happen in either order. These always exist.

Hence, it is incorrect to state that the event has or hasn't happened yet. It can end up happening before or after your current state, depending on some observer's point of view.
Re:What this means by khallow · 2012-11-20 04:32 · Score: 1

What is "GM" here? "Gravitational Mechanics"? The book?

One doesn't require Minkowski (not Euclidean) space-time in order to have space-time coordinates. All that is needed is for every point of your space-time to have a local coordinate system and for these coordinate systems and the models on top of them to be consistent with each other via change of coordinates (of both coordinates and models). This has been done.
Re:What this means by PiSkyHi · 2012-11-20 04:35 · Score: 1

Apologies... I meant GR.
Re:What this means by Anonymous Coward · 2012-11-20 05:05 · Score: 0

I don't care about determining whether an event happened. God knows it did. It is absolute. You are limited. You don't know it happened till its light reaches you. That's your problem. And your relativeness.
Re:What this means by khallow · 2012-11-20 05:13 · Score: 1

GR is defined in terms of manifolds with a Minkowski space-time metric. Local coordinate systems for every point of the manifold, which are where they overlap consistent via change of coordinates, are inherent parts of the theory.
Re:What this means by PiSkyHi · 2012-11-20 05:17 · Score: 1

GR is approximated by coordinate systems.
Re:What this means by khallow · 2012-11-20 06:38 · Score: 1

God knows it did. It is absolute.
Where's the evidence for the God point of view? And there's still no absolute ordering of events.
Re:What this means by khallow · 2012-11-20 06:45 · Score: 1

Those coordinate systems are more than just an approximation. They are the way we define space-time and everything else in the GR model completely. Each local neighborhood has its own coordinate system and different systems are consistent where they overlap via change of coordinates.
Re:What this means by SoftwareArtist · 2012-11-20 07:16 · Score: 1

A symmetry doesn't mean there are multiple universes. It describes a property of our single universe.
Think of a square in a plane. A square has lots of symmetries. You can rotate it around its center by 90 degrees, or 180 degrees, or 270 degrees, and it remains unchanged. You also can mirror it about its center horizontally, or vertically, or across either of its diagonals. Any of these operations leaves the square completely unchanged. But that doesn't mean there are many different squares. There is just one square with lots of symmetries.
CPT invariance is the same way. It doesn't even make sense to talk about a "second universe" that is "a complete CPT reversal from ours". That second universe would be completely indistinguishable from ours. It would be exactly the same universe, in the same way that rotating a square by 90 degrees leaves you with exactly the same square. CPT invariance just means that our universe can be described in two different ways that are completely equivalent. Neither one is the "right" description or the "real" description. Both of them are equally good descriptions.

--
"I'm too busy to research this and form an educated opinion, but I do have time to tell everyone my uninformed opinion."
Re:What this means by Anonymous Coward · 2012-11-20 08:32 · Score: 0

"Down" means "toward the enemy's gate."
FTFY
Re:What this means by PiSkyHi · 2012-11-20 12:44 · Score: 1

Since GR implies that the curvature of spacetime is affected directly by the matter/energy content and its distribution, it is inherently immune to simplification in any coordinate system - approximation for the purpose of showing off some math with it is what you are referring to - let's assume you are a spherical particle. GR is the principle, claiming the math we use around it is what defines it is false.
Re:What this means by khallow · 2012-11-20 14:25 · Score: 1

Since GR implies that the curvature of spacetime is affected directly by the matter/energy content and its distribution, it is inherently immune to simplification in any coordinate system
[...]

GR is the principle, claiming the math we use around it is what defines it is false.
Who said anything about simplication? A universal covering by a bunch of local coordinate systems coupled with change of coordinate rules is how the GR model is described. This is a fact not an assumption. The math indeed defines GR.

But GR doesn't fully describe actual reality in which, among other things, one can observe three other forces and quantum effects. That's also a fact.

The Ugly Details by Required+Snark · 2012-11-19 13:42 · Score: 4, Interesting

If your follow the links far enough you get here http://physics.aps.org/articles/v5/129 where they have a detailed non-mathematical description of the experiment.

After detecting and identifying the mesons, the experimenters determined the proper time difference between the decay of the two B states by determining the energy of each meson and measuring the separation of the two meson decay vertices along the e-e+ beam axis. When time-reversed pairs were compared, the BaBar collaboration found discrepancies in the decay rates. The asymmetry, which could only come from a T transformation and not a CP violation, was significant, being fourteen standard deviations away from time invariance. Thus the long wait for an unequivocal time-reversal violation in particle physics is finally over.

IANAP, but here is my understanding of the experiment. They knew that two different decay chains occur from some positron/electron collisions. If time is symmetric, there should be equal numbers of both chains. By making the beam energies different between the positron and electron (e-e+) beams, they were able to differentiate the decay order. If time symmetric decay occurred then there would be one spacial pattern in the results, and if time was asymmetric there would be another. The results conclusively show that for this subatomic event time runs in the direction we know as "forward". This is a big deal for subatomic physics.

--
Why is Snark Required?

larger question. by Anonymous Coward · 2012-11-19 13:51 · Score: 0

Yes but the larger question is. What is it pointing at?

Quick question then by gr8_phk · 2012-11-19 14:01 · Score: 1

In a Newtonian universe, light will follow the same path backwards if it's direction is reversed (bounced perfectly normal to a mirror). My question is "does this hold under relativity?". I thought the answer was yes, but IANAPhysicist so don't know if that's the accepted answer. If it does hold then there are some very interesting consequences that are never talked about.

Re:Quick question then by ceoyoyo · 2012-11-19 14:38 · Score: 1

Since photons do not routinely experience CP violation they also behave the same way forward and backwards in time.
Re:Quick question then by SoftwareArtist · 2012-11-19 15:20 · Score: 2

Yes, and not just photons. Any particle will follow the same path backward, as long as you also reverse its charge (which has no effect on a photon, since they're uncharged) and parity (which I think flips the polarization of a photon, but don't quote me on that). What CPT invariance really says is that there are two ways of describing the universe that are exactly equivalent in every way. They predict exactly the same result for any experiment you can ever do. But what one description calls "forward in time", the other one calls "backward in time".

--
"I'm too busy to research this and form an educated opinion, but I do have time to tell everyone my uninformed opinion."
Re:Quick question then by arth1 · 2012-11-19 15:22 · Score: 4, Informative

Since photons do not routinely experience CP violation they also behave the same way forward and backwards in time.
Well, photons don't experience time in either direction. Those who experience photons do, but to a photon, no time can pass because they by definition move through vacuum at c.
It also has no antiparticle (or, you could say, it is its own antiparticle), so there's no way to reverse time even if you managed to prolong the subjective lifespan of a photon beyond instantaneous.
Re:Quick question then by Anonymous Coward · 2012-11-19 20:59 · Score: 0

no time can pass because they by definition move through vacuum at c.
Interesting. What happens in other media -say water- where photons do NOT move exactly at C, but a bit slower? (that's the reason for Cherenkov Radiation). Do they experience time there? Hummm....
Re:Quick question then by wonkey_monkey · 2012-11-19 21:32 · Score: 1

no time can pass because they by definition move through vacuum at c.
What about when they move through air or water? Are they really "slowing down" or is there quantum wibbly-wobbly nonsense going on?

--
systemd is Roko's Basilisk.
Re:Quick question then by MasterPatricko · 2012-11-19 23:09 · Score: 1

Photons moving through a medium are "slowed down" by interactions of the electromagnetic field with the atoms of the medium.
Remember that a photon is just localised electromagnetic energy. In a medium, the electromagnetic fields behave differently than in a vacuum, because of the all the atoms with their various charged bits (protons, electrons) -- there is a different "resistance" to changing the field strength because the field has to move the atoms as well. This resistance to changing the field strength is what determines the speed of the electromagnetic wave.
In mathematical terms we say photons (electromagnetic waves) travel at speed c/n, where n is the refractive index of the material, and n is sqrt(epsilon * mu), where epsilon and mu are the relative permittivity and permeability (to electromagnetic fields) of the medium.
A simpler, but wrong, model you might hear is that the photons are being absorbed and reemitted many times as it passes through the medium, all while travelling at c between the atoms, but that can't be really true because otherwise light would be highly directionally spread out after exiting any high refractive index material, but we can see straight through glass and water.

--
I'd tell a UDP joke, but you may not get it. I'd tell a TCP joke, but I'd have to keep repeating it until you got it.
Re:Quick question then by rufty_tufty · 2012-11-20 01:33 · Score: 1

I think you misunderstand. Light only ever travels at the speed of light.
However when in a medium (such as water or glass) the interactions of light with the medium (by absorption/re-emission) cause the effective group velocity of the light to be slower.
One photon could pass through the block of glass and not interact with any atoms at all and therefore travel at the speed of light. However it is vastly more probable it will hit a silicon or oxygen atom and excite an electron which will then re-emit the photon a short time later.

--
"The weirdest thing about a mind, is that every answer that you find, is the basis of a brand new cliche" -
Re:Quick question then by Anonymous Coward · 2012-11-20 02:58 · Score: 0

Well, photons don't experience time in either direction. Those who experience photons do, but to a photon, no time can pass because they by definition move through vacuum at c.
Not quite, the photon doesn't "know" it moves, it thinks it's you who is moving at c, no ?
Re:Quick question then by ceoyoyo · 2012-11-20 17:21 · Score: 1

Photons interact with each other and other things. The idea of photons and CP violation is being explored:
http://prd.aps.org/abstract/PRD/v79/i6/e065020
http://arxiv.org/abs/hep-ph/9405203
Re:Quick question then by arth1 · 2012-11-21 01:48 · Score: 1

Interesting. But given that the only property affected would be the spin, this would not affect the arrow of time, I should think?
Re:Quick question then by ceoyoyo · 2012-11-21 02:54 · Score: 1

If CP is violated then T has to be as well. T violation, no matter how small or obscure (and the one the story is about is pretty obscure) gives time a defined direction.
If you're wondering why T needs to be violated when C can't be, you've got the requirements backwards. If CPT is to be preserved as a symmetry and you change P then you have to either change C or T to compensate. If you can't change C, then you HAVE to change T. What you'd end up with is a slight preference for photons with a particular parity going forward in time.

Entropy vs. T-symmetry by Roger+W+Moore · 2012-11-19 14:12 · Score: 4, Informative

The arrow of time is the reason why random bits of shrapnel and chemicals don't fly together and "un-detonate" to become hand grenades.

No, that is entropy. The reason that balls fall off tables and rarely bounce onto them (when provided with enough heat energy) is because there are many, many more states where the balls atoms vibrate incoherently and only one state (or a tiny handful) where the vibrations are organized enough to cause it to bounce back onto the table.

With mesons you can study a particle oscillating between two states. What you find is that the P(A -> B) is not equal to the P(B -> A) where B is the anti-particle state of A and there is no entropy involved. It's all to do with something called CPT symmetry which is a result of relativity and, since CP together are violated (anti-matter is not exactly the same as matter) we expect that T (time reversal symmetry) is also violated so this is an expected result.

Re:Entropy vs. T-symmetry by Anonymous Coward · 2012-11-19 20:18 · Score: 0

That's what I thought. CPT symmetry is still true, then, right? All they've done is demonstrate that T symmetry is not true on its own (which we already knew/suspected)?
So we can still have a mirror anti-universe running backwards in time (or a pocket of our universe doing that). So, nothing to do with "confirming the arrow of time", as the article headline states.
Re:Entropy vs. T-symmetry by AchilleTalon · 2012-11-20 00:04 · Score: 1

FTFA, what makes the difference here is the measurement was made independantly from the CP violation. Here is the key passage:
“It was important to measure time reversal independently of charge-parity violation because there was always the possibility something was wrong with the full picture,” says Fabio Anulli of the National Institute for Nuclear Physics in Rome, who is physics coordinator for BaBar.
Measurements indicating time reversal was likely violated had already been made in kaons at Fermilab in Batavia, Illinois and at CERN near Geneva, but in those experiments, according to Anulli, the measurement of time reversal were not disentangled from violations of charge-parity that were also present."

--
Achille Talon
Hop!

CPLEAR by Roger+W+Moore · 2012-11-19 14:17 · Score: 4, Insightful

Arrow of Time confirmed... Wheel of Time fans disappointed.

Physicists on the CPLEAR experiment will be disappointed as well - they actually discovered this effect (called T-violation) back in the 1990's before Babar was running by looking at kaon oscillations produced in low energy proton/antiproton collisions [Phys. Lett. B 444 43 (1998)]. So Babar was certainly not the first experiment to see the "arrow of time" although it is the first to do so using B mesons.

Re:CPLEAR by AchilleTalon · 2012-11-19 23:19 · Score: 5, Informative

From TFA: "Measurements indicating time reversal was likely violated had already been made in kaons at Fermilab in Batavia, Illinois and at CERN near Geneva, but in those experiments, according to Anulli, the measurement of time reversal were not disentangled from violations of charge-parity that were also present."

--
Achille Talon
Hop!
Re:CPLEAR by Roger+W+Moore · 2012-11-20 06:01 · Score: 1

...and the TFA is wrong. Read the paper.
Re:CPLEAR by cavebison · 2012-11-20 20:05 · Score: 1

back in the 1990's before Babar was running
Correction - Babar's first run was in 1989.
I'm not sure what the direction of time has to do with it, but.. heheh.. .funny elephant.

Am I Getting This Right? by Anonymous Coward · 2012-11-19 14:52 · Score: 0

So, if I paint something and then smash it, the out come will be different than if I smashed it and then painted it. Thanks, science.

Re:Can I have the time back by oldhack · 2012-11-19 14:55 · Score: 1

No. You know why? Cuz time don't go back.

--
Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.

DeLorean by Anonymous Coward · 2012-11-19 15:16 · Score: 0

next test, tomorrow at Twin Pines mall...

tsop tsirF by waynemcdougall · 2012-11-19 15:25 · Score: 5, Funny

emit fo worra diputS

--
Recycle PCs and build a wireless community network www.hillsborough.org.nz

Re:tsop tsirF by Anonymous Coward · 2012-11-19 16:12 · Score: 0

Bravo.
Re:tsop tsirF by Anonymous Coward · 2012-11-19 19:43 · Score: 0

.tsirf saw I

Slashdot Dissonance by Anonymous Coward · 2012-11-19 16:17 · Score: 0

Some articles on Slashdot begin with the phrase, "Microsoft, a big software company that makes things for computers, the thing sitting on your desk with the tiny pointing thing and the big rectangle clicky thing..." and some articles are just verbal diarrhea from someone's overly-complex thesis.

Can we please estalish some kind of basic guidelines on what doesn't warrant explaining, and what does? Because this alphabet-soup PhD shit most certainly DOES.

Sincerely,
Those of us who aren't theoretical physicists

Re:Slashdot Dissonance by Anonymous Coward · 2012-11-19 19:19 · Score: 0

Well, the Slashdot standard is quite simple: The summary is generally just some paragraph copied from the linked article. What the summary does or does not explain generally is completely independent of what you can expect Slashdot readers to know, because it wasn't written with Slashdot readers in mind. The very different levels come from the very different sources. The article here in question is from Nature and is targeted at scientists who are expected to understand all this. The articles explaining Microsoft are written for the general public who are expected in the majority to know close to nothing about computers.

Re:not really the arrow of time by bcrowell · 2012-11-19 17:40 · Score: 1

Well, except for being necessary for CP violation, which in turn is the only way we have of explaining why there isn't much antimatter around.

No, CP violation doesn't explain baryon asymmetry. CP violation is part of the standard model. Baryon asymmetry isn't explained by the standard model.

--
Find free books.

origin of foo bar by Anonymous Coward · 2012-11-19 17:47 · Score: 0

Now I know where foo bar comes from : it's the antimatter equivalent of foo .

Stupid Humans by Anonymous Coward · 2012-11-19 19:11 · Score: 0

when are you going to realize that there is no such thing as time? you perceive time's arrow because there is no such thing as time. time does not exist. you made it up. there are only bodies in motion. the speed of motion is relative to the lifespan of the observer or some other arbitrary process, all of which are things in motion. RELATIVITY!?

tihs by Anonymous Coward · 2012-11-19 19:39 · Score: 0

sppo....tahw kcuf eht os.

Stuff that matters by Anonymous Coward · 2012-11-19 20:32 · Score: 0

Finally some actual news for nerds :)

Speaking of which, what happened to that slogan at the top...?

I used to be a B meson like you... by matunos · 2012-11-19 21:01 · Score: 3, Funny

...but then I took an arrow of time in the knee.

ahhh physicists... by crutchy · 2012-11-19 22:43 · Score: 1

time runs in the reverse direction (T)

oh he's making it up as he goes along!

Q: Why did the cat slide off the roof?
A: It didn't have enough Mu.

bahahahahahahahahahahaha!!!!!!! i found that on some random physics jokes website and its the funniest joke i think i've ever heard... sad huh

This was the real joke, very funny (ironic) by Anonymous Coward · 2012-11-20 01:05 · Score: 0

YOUR "CODE" lacked error trapping here -> http://developers.slashdot.org/comments.pl?sid=3258205&cid=42016197 (if you call using prebuilt functions coding, that is - more like a kid using legos, lol!)...

---

Additionally - Didn't YOU say THIS also, in regards to coding:

"...cos we all try to write code that "looks cool" and you know, writing code that functions and easy to debug is all of secondary importance" - by crutchy (1949900) on Sunday November 18, @02:55AM (#42017605)

FROM -> http://developers.slashdot.org/comments.pl?sid=3258205&cid=42017605

"?"

QUESTION - Where's YOUR code that functions AND is easy to debug?

---

It isn't - LMAO:

* You write code like a NOOB does, completely omitting error trapping... and the proof's right in that 1st link above!

APK

P.S.=> Lastly/Again - Funny my code ran 5x perfectly here too, eh?

---

http://developers.slashdot.org/comments.pl?sid=3258205&cid=42014943

http://developers.slashdot.org/comments.pl?sid=3258205&cid=42016015

http://developers.slashdot.org/comments.pl?sid=3258205&cid=42014957

http://developers.slashdot.org/comments.pl?sid=3258205&cid=42015649

---

(As well as 100's of times the past 1.5-2 yrs. now using it vs. trolls like yourself... perfect, every single time!)

* Care to EXPLAIN those PERFECT OUTPUTS, (lol) 'CruTcHy'?

So much for this "tidbit" from you, eh (lol) 'CruTcHy':

---

"i have never been talking about the code that you actually run in your python interpreter" - by crutchy (1949900) on Sunday November 18, @04:02AM (#42017797)

Man - First of all - You can't even write ENGLISH properly - sentences begin with capital letters!

Perhaps it's MY FAULT here, lol (not)... How on EARTH could I expect you to write maintainable code WITH error trapping?

Clue/New NEWS/Newsflash : That's the code of MINE'S providing WHAT YOU NEED shown in the links above (& for others like you, as trolls, probably you posting again as ac)... rotflmao!

What's THAT kids? Oh, yes - that's right: You GUESSED IT - A dose of "ReVeRsE-PsyChoLoGy"... lmao!

... apk

Re:This was the real joke, very funny (ironic) by crutchy · 2012-11-20 08:49 · Score: 1

noob
Re:This was the real joke, very funny (ironic) by Anonymous Coward · 2012-11-20 10:22 · Score: 0

noobs put out code without error handlers crutchy. You're the noob doing it that way.
Re:This was the real joke, very funny (ironic) by crutchy · 2012-11-23 09:14 · Score: 1

you've never seen my code so you're getting pretty desperate, but at least you're calling them error "handlers" now rather than noobish "traps"

only a noob like you would feel a need to wrap an exception handler around a print statement... maybe you should have put an exception handler around your exception handler, just in case you fucked that up too
Re:This was the real joke, very funny (ironic) by Anonymous Coward · 2012-11-23 12:17 · Score: 0

Noobs write code minus error handlers. You did that noob.
Re:This was the real joke, very funny (ironic) by crutchy · 2012-11-23 13:29 · Score: 1

rhetorical question: which is more bug prone, and which one actually has a bug?

s = "123"
s = s[::-1]
print s

or...
code here: http://slashdot.org/comments.pl?sid=3258205&cid=42015649

answer: APK's bullshit code has a Python indentation bug on the fifth line! ...and the funniest part is that he either can't even see it, or can but doesn't want to acknowledge it and instead wants to keep posting his incompetent garbage all over slashdot

you might have a couple of exception handlers APK, but the code in the linked post won't even interpret let alone handle any errors!

noobs may not use exception handlers, but noobs also use exception handlers incorrectly, which you have. exception handlers are good for handling specific exceptions (user input particularly).
wrapping swathes of code in exception handlers stinks of noob.
Re:This was the real joke, very funny (ironic) by Anonymous Coward · 2012-11-23 17:36 · Score: 0

This shows otherwise (your words you don't live up to) http://developers.slashdot.org/comments.pl?sid=3258205&cid=42039353
Re:This was the real joke, very funny (ironic) by Anonymous Coward · 2012-11-23 19:46 · Score: 0

This shows otherwise
no it doesn't
Re:This was the real joke, very funny (ironic) by Anonymous Coward · 2012-11-24 00:39 · Score: 0

This shows otherwise and your words you don't live up to http://developers.slashdot.org/comments.pl?sid=3258205&cid=42039353
Re:This was the real joke, very funny (ironic) by Anonymous Coward · 2012-11-24 16:18 · Score: 0

no actually that doesn't show anything, but is yet another example of where to find a copy of your buggy code...
forget about error handlers dipshit... they won't debug your code for you hahahahaha!!!! (what a moron)

?oS by ZonkerWilliam · 2012-11-20 02:45 · Score: 1

?yaw thgir eht si, yaw hciW

Re:?oS by Anonymous Coward · 2012-11-20 09:13 · Score: 0

?yaw thgir eht si, yaw hciW

If you meet an alien, and you've agreed that you greet each other by extending your right hand/tentacle and shaking it, and the alien extends its left tentacle, both of you should abort the ceremony and run away before you annihilate each other in a blast of gamma rays.

Naught by Anonymous Coward · 2012-11-20 02:46 · Score: 0

Since time is a human invention, it doesn't exist in reality, hence, no directionality.

Matter Anti-Matter by Anonymous Coward · 2012-11-20 02:49 · Score: 0

Could this be part of the puzzle why there is more matter than anti-matter in the Universe?

Re:I'm having a baby... by fonske · 2012-11-20 02:59 · Score: 1

...elephant.
It's trunk is already hanging out.

Obligatory by Anonymous Coward · 2012-11-20 04:17 · Score: 0

I used to be a physicist like you but then I took an arrow (of time) to my knee

What does this mean for the Groucho co-efficient? by Curseyoukhan · 2012-11-20 05:18 · Score: 2

"Time flies like an arrow. Fruit flies like a banana." Is it still a banana going backwards or do fruit flies now like an ananab? Also, can anyone explain what this paper means in English for an average moron like me?

Monsieur, how 'bout another one by tepples · 2012-11-20 05:42 · Score: 1

Funny - I read the article backward and I got that Paul is dead.

What does it say forward? Is it "Monsieur, monsieur, monsieur, how 'bout another one" like the end of "I'm So Tired", or "Cranberry sauce" like the end of "Strawberry Fields Forever"?

Not the arrow of time by tbid18 · 2012-11-20 06:57 · Score: 1

According to physicist Sean Carroll, who specializes in this sort of thing. I figured people might enjoy reading this, in case it hasn't been posted.

Hmmm by TheSkepticalOptimist · 2012-11-20 08:03 · Score: 1

Whenever I read stuff like this I think there are a bunch of physicists snicking and laughing in front of a screen watching Slashdot and saying "Oh my spaghetti monster I can't believe they are buying into this bullshit. We can say anything we want and they'll believe us. Quick, post an article about time unicorns and looms that predict the future. he he he".

--
I haven't thought of anything clever to put here, but then again most of you haven't either.

So - is CPT symmetry confirmed or busted? by BeadyEl · 2012-11-20 12:31 · Score: 1

I couldn't quite tell from reading ...

Not about Time Travel by Anonymous Coward · 2012-11-20 17:12 · Score: 0

/. sensationalized the headline as usual. this is not about time travel.

"directly compare the rate of one process to its precise time-reverse. You can measure the lifetime of a muon, for example, as it decays into an electron, a neutrino, and an anti-neutrino. But it’s very difficult (utterly impractical, actually) to shoot a neutrino and an anti-neutrino directly at an electron and measure the probability that it all turns into a muon. So what you want to look at are oscillations: one particle turning into another, which can also convert back. "

Re:not really the arrow of time by ceoyoyo · 2012-11-20 17:30 · Score: 1

Hm...

http://mr.crossref.org/iPage/?doi=10.1070%2FPU1991v034n05ABEH002497

For the subscription impaired, the summary from Wikipedia:

In 1967, Andrei Sakharov proposed[2] a set of three necessary conditions that a baryon-generating interaction must satisfy to produce matter and antimatter at different rates. These conditions were inspired by the recent discoveries of the cosmic background radiation [3] and CP-violation in the neutral kaon system. [4] The three necessary "Sakharov conditions" are:
Baryon number violation.
C-symmetry and CP-symmetry violation.
Interactions out of thermal equilibrium.

Re:not really the arrow of time by ceoyoyo · 2012-11-20 17:32 · Score: 1

Oh, and just to address the rest of your statement:

The Standard Model can incorporate baryogenesis, though the amount of net baryons (and leptons) thus created may not be sufficient to account for the present baryon asymmetry; this issue has not yet been determined decisively.
Baryogenesis within the Standard Model requires the electroweak symmetry breaking be a first-order phase transition, since otherwise sphalerons wipe off any baryon asymmetry that happened up to the phase transition, while later the amount of baryon non-conserving interactions is negligible. [7]
The phase transition domain wall breaks the P-symmetry spontaneously, allowing for CP-symmetry violating interactions to create C-asymmetry on both its sides: quarks tend to accumulate on the broken phase side of the domain wall, while anti-quarks tend to accumulate on its unbroken phase side. This happens as follows:[5]
Due to CP-symmetry violating electroweak interactions, some amplitudes involving quarks are not equal to the corresponding amplitudes involving anti-quarks, but rather have opposite phase (see CKM matrix and Kaon); since time reversal takes an amplitude to its complex conjugate, CPT-symmetry is conserved.

http://en.wikipedia.org/wiki/Baryogenesis#Baryogenesis_within_the_Standard_Model

There's no hiding from YOUR own words by Anonymous Coward · 2012-11-24 01:05 · Score: 0

That link leads to 3 lines of your "code" that isn't error handled that isn't easy to debug. You demanded that of good code in YOUR OWN WORDS no less there http://developers.slashdot.org/comments.pl?sid=3258205&cid=42039353

Re:There's no hiding from YOUR own words by crutchy · 2012-11-24 15:54 · Score: 1

i already debugged it. not hard to debug 3 lines of code. it doesn't need exception handlers.

...and at least i actually debug my code; you still can't acknowledge the bug in yours - example here http://developers.slashdot.org/comments.pl?sid=3258205&cid=42014957

another rhetorical question: how does adding error handlers make code easier to debug?
Re:There's no hiding from YOUR own words by Anonymous Coward · 2012-11-24 16:38 · Score: 0

you don't acknowledge his code ran 5x perfectly in front of you.
Re:There's no hiding from YOUR own words by Anonymous Coward · 2012-11-24 16:40 · Score: 0

How would you diagnose a printer/printer driver failure minus dumps of structured error handler codes in error handlers? That's only 1 i-o example too.
Re:There's no hiding from YOUR own words by crutchy · 2012-11-24 18:59 · Score: 1

exception handlers are very useful for any kind of input or api calls etc

i wouldn't just wrap all my code in an exception handler though. i would wrap certain calls in handlers to handle specific and expected exceptions

exception handlers have absolutely nothing to do with code debugging
wrapping code in exception handlers won't get rid of bugs (surely that's obvious to you)

so where's the printer driver code in your buggy function douchebag?
Re:There's no hiding from YOUR own words by crutchy · 2012-11-24 19:02 · Score: 1

i didn't see any code running... for all i know you could have manually typed the supposed output

there is a bug in your posted code though. if you can't see it, then you're an incompetent noob (especially since i've spelled it out to you on a few occasions)
Re:There's no hiding from YOUR own words by Anonymous Coward · 2012-11-25 01:08 · Score: 0

That's a single I/O example, here's another: What if the console IO system bugged out, for whatever reasons? Without dumping structured error handlers the Python interpreter has, you'd burn a lot of time possibly in having to figure out what the problem really is. That's where you go wrong by not using error handling crutchy. You did say literally that writing code that is easy to debug is critical, then why do you omit error handling code?
Re:There's no hiding from YOUR own words by crutchy · 2012-11-26 09:00 · Score: 1

what if an alien spaceship tried to infect your rediculous Python code with some alien virus? you would be totally fucked without exception handlers i'm sure :)

exception handlers aren't for debugging... fool... they are for.... (drum roll)... handling exceptions!!!! hahahaha!!! (and if you are wrapping code in handlers for unknown exceptions you're doing it for the wrong reason... exception handlers are for handling expected exceptions - popping up a message that says something like "oh oh something fucked up and the programmer has no idea what" isn't very reassuring for the user).

maybe you need a bit more practice debugging to understand how it differs (try debugging your stupid function first)

google also no doubt has some handy tips
Re:There's no hiding from YOUR own words by Anonymous Coward · 2012-11-26 09:28 · Score: 0

You said to use error handlers for input from users ONLY? Ever heard of using keypress events in entry fields and validating entry there instead, or are you still in DOS type coding only?? Obviously are you, noob. Additionally, when you dump structured error handlers you get what is wrong a good 95% of the time and it's correct and saves you time debugging. You need to learn more noob. No wonder you're still a done nothing zero in computing.
Re:There's no hiding from YOUR own words by crutchy · 2012-11-26 17:43 · Score: 1

You said to use error handlers for input from users ONLY?
bullshit moron... learn to read... what i said (quoted from my message) was "exception handlers are very useful for any kind of input or api calls etc".
did you see the "etc" on the end there?

Ever heard of using keypress events in entry fields and validating entry there instead
i use onchange events etc for validation, but in those events, i usually wrap my single line of code for converting from string to integer (or whatever the case) with an exception handler, and the handler code changes the color of the label or something like that.

when you dump structured error handlers you get what is wrong a good 95% of the time and it's correct and saves you time debugging
no you don't and no it doesn't... maybe you should look up the definition of "debugging"

anyway, i've had enough educating you. if you want more advice you're going to have to start paying by the hour... and i double the rate for idiots like you

You're so incompetent I have to tell you! by Anonymous Coward · 2012-11-25 01:04 · Score: 0

No, 'CruTcHy' (lol)? What were these then:

---

http://developers.slashdot.org/comments.pl?sid=3258205&cid=42014943

http://developers.slashdot.org/comments.pl?sid=3258205&cid=42016015

http://developers.slashdot.org/comments.pl?sid=3258205&cid=42014957

http://developers.slashdot.org/comments.pl?sid=3258205&cid=42015649

---

Hmmm?

5 absolutely PERFECT outputs from my Python script for trolls are above & 100's of times before those perfectly for oh, around 2 yrs. here, just giving them what they NEED (since I am such a nice guy & all that, lol) & what's THAT, kids?

Ah, you guess it - a dose of "ReVeRsE-PsyChoLoGy"

APK

P.S.=> Have YOU ever considered that when I paste my template into /.'s board engine, it is NOT catching & formatting it properly when I paste it in?

What matters most, is PEFECT "ReVeRsE-PsyChoLoGy" outputs to trolls (such as yourself)...

... apk

Re:You're so incompetent I have to tell you! by crutchy · 2012-11-26 08:54 · Score: 1

yep... the bug is in at least two of those posts (i didn't bother clicking on the rest but i'm sure they are the same)

if you are using a script, it isn't the same as the one you post, because your posted code has an indentation bug and won't interpret (and no amount of error handling will change that lol)

leave the bug in there... at least i'll be able to continue to highlight it to the rest of the slashdot readership and they can decide how much of a noob you are for themselves
Re:You're so incompetent I have to tell you! by Anonymous Coward · 2012-11-26 09:31 · Score: 0

Not as big of a noob as one that *thinks* error handlers are for inputs by users only (try using entry field keypress events to validate data instead, noobie), and you also omit error handling completely, the mark of a noob. It has a lot of uses in debugging and you said one ought to strive to make code that is easy to debug. You can't even get your own story straight.
Re:You're so incompetent I have to tell you! by crutchy · 2012-11-26 17:45 · Score: 1

my story is straight... you're confused because you think debugging has something to do with error handling... you poor ignorant moron

You've convinced us you're a NOOB... apk by Anonymous Coward · 2012-11-26 22:58 · Score: 0

Only a noob like you would attempt to counter for bad user inputs by error handlers when it should be done on keypress events in GUI entry fields, you utter NOOB.

APK

P.S.=> Now I am utterly CONVINCED you're a total noob, and by no means, a professional programmer... heck - you CAN'T EVEN PROGRAM IN C, for Pete's sake (lol)...

... apk

Re:You've convinced us you're a NOOB... apk by crutchy · 2012-11-28 09:04 · Score: 1

you CAN'T EVEN PROGRAM IN C
just because i don't doesn't mean i can't

and i get paid for programming php/html/js/css/sql, so why would i give a shit about c?

Come on now crutch "ole boy": Hop to it! by Anonymous Coward · 2012-11-26 23:12 · Score: 0

Oh, so NOW 'CruTcHy' (lol) "flips the script" changing what he said, lol, "adding on to it" (what a joke you are - you don't even KNOW how to setup code vs. bad user inputs properly noob).

Hey stupid?

On user inputs, you USE KEYPRESS EVENTS in entry fields to trap bad data users may input.

APK

P.S.=> Now, THIS always make 'CruTcHy' (lol) pull his std. "Run, Forrest: RUN!!!":

---

CruTcHy - can you prove your statement here with any information?

http://slashdot.org/comments.pl?sid=3272015&cid=42083563

---

(After all - YOU STATED IT, now back it up with proof!)

Oh yea, on that note>

We saw your last "fine ReAcTioN" (lmao - "NOT", more like a profanity ridden "FoAmiNg-@-ThE-MouTh" lunatic's howl, lol) to that, here -> http://slashdot.org/comments.pl?sid=3272015&cid=42097505

Re:Come on now crutch "ole boy": Hop to it! by crutchy · 2012-11-28 09:13 · Score: 1

Oh, so NOW 'CruTcHy' (lol) "flips the script" changing what he said, lol, "adding on to it"
i quoted from the original message dipshit. i didn't add anything.

getting pretty desperate aren't you?
On user inputs, you USE KEYPRESS EVENTS in entry fields to trap bad data users may input.
that's one way, but not necessarily the best because you may be trying to validate incomplete user input, so if a user startes by entering a minus symbol with the intention of entering a negative number, how can you validate that on keypress? the next key may be a number, which would make it valid, or they may move on leaving just an invalid minus symbol. using a keypress event handler is similar to a change event handler in that you can do something non-intrusive (like change the color of the text box label to red) as the user types until a valid input is achieved, but you shouldn't show any kind of intrusive error message until the user has actually finished entering their input (with an lostfocus or similar event).

anyway, i know you won't even read this let alone understand it.

you're also starting to get boring APK, so unless you can step up the intelligence of your conversation i'm probably going to move on

'CruTcHy' - you haven't coded much have you? by Anonymous Coward · 2012-11-28 13:35 · Score: 0

It's THE BEST way, bar-none, since it catches bogus material, by character, JUST as it is entered... Then you can validate on other events if you wish (not as good usually), OR, just build exceptions into your filter.

"so if a user startes by entering a minus symbol with the intention of entering a negative number, how can you validate that on keypress?" - by crutchy (1949900) on Wednesday November 28, @04:13PM (#42122345)

Easy - ALLOW for it during your checks in your filtering tests!

Come on... lol!

(Plus - There's also RAD environments that have gui entry field controls that DO checks on numerical inputs, vs. say, alpha-numeric as well!)

---

"anyway, i know you won't even read this let alone understand it." - by crutchy (1949900) on Wednesday November 28, @04:13PM (#42122345)

'CruTcHy' (lol) - I can tell you haven't DONE MUCH CODING from your rather weak "methods" of data input validation, AND, certainly NOT IN GUI PROGRAMS evidently.

Plus, like I've said to you, time & again? The day you've done as much as I have, BETTER & EARLIER especially?? Is the day a NOOB LIKE YOU can "attempt to condescend to me"... Hell:

YOU CAN'T EVEN BACKUP YOUR B.S. here -> http://slashdot.org/comments.pl?sid=3272015&cid=42083563

Since when you were asked to, this was your "RaGiNg ReSpoNse" (lmao):

"you're a moron for even assuming i need to justify myself... fuck knuckle if you don't like what i say, go back to fucking your sister" - by crutchy (1949900) on Monday November 26, @03:38PM (#42097505)

FROM -> http://slashdot.org/comments.pl?sid=3272015&cid=42097505

Gee 'CruTcHy' (lol) - did someone touch a "sensitive spot", LIKE THE TRUTH ABOUT YOU NOT BEING WHAT YOU SAID in the links before it?

Absolutely...

The rest here just told me ALL tje rest of what I needed to know & that is not only do you NOT program in C (a fundamental for any programmer, true programmer that is, not a noob like you), but you've never coded any GUI RAD environs either apparently!

APK

P.S.=> This is how I absolutely KNOW you've been doing some LIMITED form of coding (which Python tends to explain a great deal of, since it does so much "hand-holding" for users of it, which is a good thing, BUT, also a BAD thing too)...

... apk

Re:'CruTcHy' - you haven't coded much have you? by crutchy · 2012-12-03 09:03 · Score: 1

not that it matters, but I don't program C because I don't have a need for it (C is only better than other languages for low-level - such as hardware - stuff) and I also don't program python because as you eluded to it is for noobs (hence why you use it). I personally program PHP/JS/HTML/CSS/SQL mainly (that's what I get paid to do sometimes at the moment) but I get paid to do Delphi programming (although not as much as I used to). Your code was actually the first piece of python that I've ever debugged... its just a pity you seem to be incapable of doing the same.

Easy - ALLOW for it during your checks in your filtering tests!
you're right that it is easy to filter inputs, but not on keypress. you will need another event to handle that. that's why i mentioned events such as lostfocus, but there are of course others (keypress is definitely one event that can be used for partial input validation, but not on its own).

if you have your so called "filter tests" (noobish terminology much) only in a keypress event, you will either allow invalid input (such as a lone "-" symbol) or you will prevent entering of valid inputs (such as "-5.4" for example).

you are about as noob as they come APK, but you are definitely the most arrogant self-rightious noob I have ever come across, which makes you look even more stupid on this very public and open forum.

btw, have you found that bug yet?
Re:'CruTcHy' - you haven't coded much have you? by Anonymous Coward · 2012-12-03 10:19 · Score: 0

The code ran perfectly. Nothing to debug. You didn't debug it. You can't even prove you're a professional programmer and became enraged when asked to. This shows us you haven't done anything others noticed. You project your noob state. Keypresses are excellent for user input validation right as it happens. You only show us you are a noob further on that topic.

'CruTcHy' (lol) the troll, caught in lies... apk by Anonymous Coward · 2012-11-28 13:49 · Score: 0

Did YOU say THIS, 'CruTcHy'? Yes, you did & verbatim quoted below (that you don't program in C, literally):

"hahaha i'd love to know what "c program" you're talking about now (particularly since i don't program c)... - by crutchy (1949900) on Sunday November 18, @04:04AM (#42017803)

FROM -> http://developers.slashdot.org/comments.pl?sid=3258205&cid=42017803

("BAD BOY 'CruTcHy' (lol) - lying was your undoing!)

---

Another LIE here too, 'CruTcHy' (lol)?

and i get paid for programming php/html/js/css/sql, so why would i give a shit about c?" - by crutchy (1949900) on Wednesday November 28, @04:04PM (#42122231)

Riiigghhtt... then, why did you "FoAm-@-ThE-MouTh" when asked to PROVE that, hmmm? See here:

"you're a moron for even assuming i need to justify myself... fuck knuckle if you don't like what i say, go back to fucking your sister" - by crutchy (1949900) on Monday November 26, @03:38PM (#42097505)

FROM -> http://slashdot.org/comments.pl?sid=3272015&cid=42097505

Gee 'CruTcHy' (lol) - did someone touch a "sensitive spot", LIKE THE TRUTH ABOUT YOU NOT BEING WHAT YOU SAID?

APK

P.S.=> You really BLEW IT, 'CruTcHy' (lol) - Catching trolls like you in their lies are how I dust a lot of online trash like you, ALL THE TIME (you only did it, to yourself)...

... apk

Re:'CruTcHy' (lol) the troll, caught in lies... ap by crutchy · 2012-12-03 09:19 · Score: 1

you appear to have difficulty comprehending basic english... maybe you should actually look up "don't" and "can't" in the dictionary

as i said before (not that i expect it to sink in any more than the last time i said it) but just because i don't program c doesn't mean i can't... i can program c if i need to. i just don't need to

Re:'CruTcHy' (lol) the troll, caught in lies... ap by Anonymous Coward · 2012-12-03 09:38 · Score: 0

You said you don't program C. You're a web noob, nothing more.

Re:'CruTcHy' (lol) the troll, caught in lies... ap by crutchy · 2012-12-03 18:29 · Score: 1

you're an idiot. nothing more

last time i checked delphi wasn't primarily for web programming, but i guess you're a noob when it comes to delphi as well so what more can i expect from such a noob as yourself

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