explain xkcd - User contributions [en]

Talk:3027: Exclusion Principle

2024-12-23T10:39:45Z

Gertuviti: Add comment on where the exclusion principle comes from and why it's fundamental.

It should be noted, that amusingly, since the quantum gravity has yet to be full explained thanks to the fact that gravity affects, and that for all we know, Exclusion Principle may be just as valid, if not more so, to be on the list as Gravity (even though Exclusion Principle should not, generally, be on this list.) {{unsigned|LilithRose|06:48, 21 December 2024}}
: I'm in agreement. "Fundamental Forces" aren't an unalterable fact about the physical universe - they are scientists' best explanation for the unalterable facts about the physical universe until we find a better one. As a result there could be an underlying reason for the exclusion principle being just as fundamental to the universe as electromagnetism - we just don't know it yet. [[User:Kev|Kev]] ([[User talk:Kev|talk]]) 12:39, 22 December 2024 (UTC)
:: Just to be clear, there *is* an underlying reason for the exclusion principle being just as fundamental to the universe as electromagnetism, and physicists know what it is. The only thing is the exclusion principle isn't a fundamental *force*, it's a different kind of fundamental thing.

:: In short, the exclusion principle necessarily arises as a property of certain particles in any system that includes quantum mechanics. If I had to try to give a rough outline of the reason why, I'd say it's something like this:

:: Suppose you construct an equation describing a quantum system with two particles that are in different positions but are otherwise identical. In many standard examples, this equation would look like the sort of wave equation you get in many problems that use the Schrodinger equation, where the square of the equation represents the probability of the two particles being observed in a particular state.

:: Now suppose those particles swap positions. What happens to the equation? Well, since the particles are identical, the observed probabilities must be the same; if there was an observable difference from merely swapping their positions, then the particles wouldn't be identical.

:: However, since the probabilities are the *square* of the equation, that actually leaves two possible solutions for what the equation could be, for exactly the same reason that the square root of 4 has the two possible solutions of 2 and -2. Similarly, the equation of the swapped particles can either be exactly the same as for the unswapped position *or* it could be negated. Which version you get depends on the properties of the particle itself. Particles where the swapped equation stays the same are called bosons. Particles where the swapped equation negates are called fermions.

:: This negation is what causes the exclusion principle (and indeed, the behaviors unique to fermions more generally), because it means certain combinations of fermions will subtract rather than add amplitude to the final wave function, decreasing the probability of those states occurring, and in some cases even fully zeroing out the amplitude, resulting in a zero probability of certain states happening at all.

:: For example, the most familiar case of this effect is how two electrons cannot be in precisely the same state in an atom. To see why that's true, suppose that really did happen. By the logic earlier, swapping those electrons must change the sign of the equation describing them, since this is true of all fermions. However, since the two electrons are in precisely the same state after the swap (note that not even their positions changed, unlike the earlier case discussed), it must also be the case that the resulting equation is exactly the same. The only solution for the conditions y=-x and also y=x is if x=y=0, meaning the probability of this happening is zero.

:: By contrast, that above logic doesn't apply to bosons, because swapping them doesn't need to negate their wave function, so there can be some probability of two or more bosons being in completely identical states, even including identical positions.

:: If you'd like a more detailed or precise explanation, most intro to quantum mecahnics textbooks have a chapter on the exclusion principle. [[User:Gertuviti|Gertuviti]] ([[User talk:Gertuviti|talk]]) 10:39, 23 December 2024 (UTC)

== Polymagnetic topologies as "color" charge, strong vs weak, etc? ==

I'm increasingly under the impression that these forces & principles, are each an expression of complex electromagnetic interactions? I've never quite understood why they're viewed as separate forces, instead of distinct-but-related expressions of a single type of force across complex topologies.

Particularly, I'm unclear why quark\gluon "color" interactions are seen as anything other than topologically-asymmetric fields interlocking; it just looks like the behavior of polymagnet fields, to me. (By the way, I'm glad there's now a common term, "polymagnetic", for the patterned fields that I'm sure many of us assembled while playing with tiny neodymium magnets & wire, as kids! Arranging multiple cores for a smaller, denser field, & observing that the patterns could interlock, felt like major 'Aha!' moments for me, at the time.)

I was so frustrated by my own feeling of "this complex thing I know very little about, really seems to have a very basic underlying principle that's being widely misconstrued", that [https://www.perplexity.ai/search/i-m-increasingly-under-the-imp-Q83bSr8pRXqMf64_VxKMZQ I've petitioned a mindless bot to hear my case.] (You'd have to scroll at least about halfway down, to get to any prompts even slightly interesting.) I'm probably wasting ''everyone's'' time with this, but it has been bothering me, more & more for ''decades,'' & my reading so far hasn't lessened that.

Why is everyone so insistent that these 'other' forces aren't magnetism? Seems like quite literally ''everything'' is magnetism, to me. Besides a formal education in the matter, what the heck am I missing, here?

[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 15:38, 21 December 2024 (UTC)

:I don't know what you mean by "complex topologies." Which topology? The reason we know the strong and weak interactions are not the electromagnetic interaction is that they have completely different gauge symmetries, among other reasons. The electromagnetic interaction has local symmetry group U(1), and the strong interaction has SU(3). Behaviorally-speaking, they are completely different in almost every respect, affecting different sets of particles, having different strengths, having different potentials, different ranges, carried by different fields, etc. Just as an example, an electron doesn't interact via the strong force ''at all.''

:It is likely that at extremely high energies, the electromagnetic, weak, and strong interactions are all unified. A theory describing this hypothetical union is called a grand unified theory or GUT, and detecting this experimentally is a major objective of modern physics. The unified "electroweak" interaction has already been observed at lower energies. But that doesn't mean the weak interaction is "just magnetism" or that electromagnetism is "just weak." They are both a consequence of a broken symmetry. The fully symmetric grand unified field would not resemble any one of the interactions that we see at lower energies but would be a symmetric combination of all of them. [[User:EebstertheGreat|EebstertheGreat]] ([[User talk:EebstertheGreat|talk]]) 16:38, 21 December 2024 (UTC)

: I absolutely won't claim any kind of knowledge, but Richard Behiel's video series on quantum mechanics, culminating in his 3-hour video on electromagnetism as a gauge theory is INCREDIBLE and absolutely explained a lot to me[[Special:Contributions/172.71.191.51|172.71.191.51]] 23:24, 22 December 2024 (UTC)Bumpf

== Actually explaining the Pauli Principle ==

:"Electrons don't like to be in the same 'spot'" is plain wrong. "Same quantum number set" is the buzzword - remember, two electrons fit in the s orbital, one spin up, one spin down. "Spin-statistics theorem" is a good place to start to ponder about the why. [[Special:Contributions/162.158.95.145|162.158.95.145]] 09:40, 22 December 2024 (UTC)
:: Way too complicated, please change the universe so that "same spot" is good enough [[User:Kev|Kev]] ([[User talk:Kev|talk]]) 12:35, 22 December 2024 (UTC)

440: Road Rage

2024-05-04T20:30:02Z

Gertuviti: /* Explanation */ Add missing plural

{{comic
| number = 440
| date = June 23, 2008
| title = Road Rage
| image = road rage.png
| titletext = Okay, now just as the loss hits him, slam on the brakes.
}}

==Explanation==
{{w|Road rage}} refers to aggressive behavior exhibited by (usually angry) motorists towards other people on or near the road. It can take the form of excessive honking, uncharacteristically aggressive driving, and using obscene gestures or language, among other behaviors.

In this comic, [[Black Hat]] is driving a car, and [[Danish]] is with him in the passenger's seat. Black Hat gets annoyed because the car behind him is "{{w|tailgating}}" (following too close behind Black Hat's car).

Danish decides to fight back, but rather than engaging in typical instances of road rage, she turns on her laptop and finds that the car behind them also has a laptop running. Since the cars are so close, the other laptop is well within WiFi range, so she manages to establish a WiFi connection with the laptop in the other car. Then, Danish finds a security hole (in the comic, a "remote exploit"). She uses it to break into the laptop and install a speech synthesizer. This means that the laptop in the car behind just starts saying words at Danish's will.

The driver of the other car is puzzled when he starts hearing a voice. He is completely clueless about where the voice comes from. Also, because he is driving alone, he is probably frightened (or nervous at least) to find that someone is speaking inside his car. The "shot in the dark" is the gamble that this statement is meaningful to the tailgater. In order for it to psychologically impact the driver, he would have to have either been involved in someone's death, or have known someone who died in a way that he blames himself for (or could be convinced to blame himself for), and that person would need to be female for the "she" pronoun to work. There are a large number of different ways this phrase could be meaningful to a person, ranging from actual murder to being involved in an accident to simply losing a loved one in a way he feels he could have prevented. Danish obviously keeps the accusation vague to maximize the odds of it impacting the tailgater, but the odds are still relatively low that it would be meaningful. Despite the poor chances, this appears to land, as the tailgater is evidently impacted by the disembodied voice blaming him for this unspecified person's death.

In the title text, Danish continues her revenge, asking Black Hat to slam on the brakes. So-called "{{w|Brake check|brake checking}}" is a common (though highly unsafe) method of road rage against tailgaters. At minimum, it forces them to abruptly decelerate and hopefully frightens them, but the danger is that they don't have room to stop in time and cause a collision. The joke is that, having already achieved a complicated and psychologically painful form of revenge, Danish wants to follow it up with a much more conventional form at the worst possible time. Since it is commonly believed that the blame for such types of accidents will always be given to the driver of the car behind, and since we know Black Hat is a sadistic bastard, Black Hat would no doubt enjoy adding both the blame and the traffic accident on top of what Danish has already accomplished. This may seem ironic, as Black Hat and Danish would be risking having their own car struck, but they would no doubt rather make an example than avoid the accident.

In truth however, while many jurisdictions do have a presumption that the rear driver is at fault in the event of a rear-end collision, that is only an initial presumption that can be rebutted by the facts of the case. Deliberately slamming your brakes for no good reason except to cause a traffic accident is illegal in virtually every jurisdiction, and that would be more than sufficient to defeat the presumption.

If this happened in reality, then assuming Cueball and Black Hat both had sufficient legal savvy to argue their cases properly, Cueball would at worst have partial responsibility for the accident due to his tailgating. Black Hat would have either partial or whole responsibility for the accident, he would be convicted of reckless driving and intentional collision, and he may be investigated for possible insurance fraud. In addition to the legal consequences, Cueball, Black Hat and Danish may also experience some combination of fractured bones, spinal injury, and brain damage due to the level of force typically imparted on both cars in such crashes. In short, this is much more physically and legally hazardous for Black Hat than popular perception tends to believe.

==Transcript==
:[Black Hat is driving, and Danish, who seems to be his equal, is in the passenger's seat. They are closely followed by some other vehicle.]
:Black Hat: That guy's tailgating me.
:Danish: I'll take a look.

:[A car is shown to be closely behind Black Hat's car.]
:Danish: His laptop's running, probably in the back seat. And... yup, the WiFi autoconnects.

:[Close-up of Danish using a laptop.]
:Danish: Now we just scan for remote exploits... install speech synth... And take a shot in the psychological dark.

:[Cueball's car.]
:Laptop: Hello.
:Cueball: What? Who's there?
:Laptop: She'd be alive if it weren't for you.
:Cueball: ...Oh God.

==Trivia==
This may be a continuation of [[433: Journal 5]], with Black Hat taking Danish to the "date" that was mentioned.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Black Hat]]
[[Category:Comics featuring Danish]]

440: Road Rage

2024-05-04T20:26:26Z

Gertuviti: /* Explanation */ Elaborated on the legality of Black Hat's actions and what legal consequences he and Cueball might face.

{{comic
| number = 440
| date = June 23, 2008
| title = Road Rage
| image = road rage.png
| titletext = Okay, now just as the loss hits him, slam on the brakes.
}}

==Explanation==
{{w|Road rage}} refers to aggressive behavior exhibited by (usually angry) motorists towards other people on or near the road. It can take the form of excessive honking, uncharacteristically aggressive driving, and using obscene gestures or language, among other behaviors.

In this comic, [[Black Hat]] is driving a car, and [[Danish]] is with him in the passenger's seat. Black Hat gets annoyed because the car behind him is "{{w|tailgating}}" (following too close behind Black Hat's car).

Danish decides to fight back, but rather than engaging in typical instances of road rage, she turns on her laptop and finds that the car behind them also has a laptop running. Since the cars are so close, the other laptop is well within WiFi range, so she manages to establish a WiFi connection with the laptop in the other car. Then, Danish finds a security hole (in the comic, a "remote exploit"). She uses it to break into the laptop and install a speech synthesizer. This means that the laptop in the car behind just starts saying words at Danish's will.

The driver of the other car is puzzled when he starts hearing a voice. He is completely clueless about where the voice comes from. Also, because he is driving alone, he is probably frightened (or nervous at least) to find that someone is speaking inside his car. The "shot in the dark" is the gamble that this statement is meaningful to the tailgater. In order for it to psychologically impact the driver, he would have to have either been involved in someone's death, or have known someone who died in a way that he blames himself for (or could be convinced to blame himself for), and that person would need to be female for the "she" pronoun to work. There are a large number of different ways this phrase could be meaningful to a person, ranging from actual murder to being involved in an accident to simply losing a loved one in a way he feels he could have prevented. Danish obviously keeps the accusation vague to maximize the odds of it impacting the tailgater, but the odds are still relatively low that it would be meaningful. Despite the poor chances, this appears to land, as the tailgater is evidently impacted by the disembodied voice blaming him for this unspecified person's death.

In the title text, Danish continues her revenge, asking Black Hat to slam on the brakes. So-called "{{w|Brake check|brake checking}}" is a common (though highly unsafe) method of road rage against tailgaters. At minimum, it forces them to abruptly decelerate and hopefully frightens them, but the danger is that they don't have room to stop in time and cause a collision. The joke is that, having already achieved a complicated and psychologically painful form of revenge, Danish wants to follow it up with a much more conventional form at the worst possible time. Since it is commonly believed that the blame for such types of accident will always be given to the driver of the car behind, and since we know Black Hat is a sadistic bastard, Black Hat would no doubt enjoy adding both the blame and the traffic accident on top of what Danish has already accomplished. This may seem ironic, as Black Hat and Danish would be risking having their own car struck, but they would no doubt rather make an example than avoid the accident.

In truth however, while many jurisdictions do have a presumption that the rear driver is at fault in the event of a rear-end collision, that is only an initial presumption that can be rebutted by the facts of the case. Deliberately slamming your brakes for no good reason except to cause a traffic accident is illegal in virtually every jurisdiction, and that would be more than sufficient to defeat the presumption.

If this happened in reality, then assuming Cueball and Black Hat both had sufficient legal savvy to argue their cases properly, Cueball would at worst have partial responsibility for the accident due to his tailgating. Black Hat would have either partial or whole responsibility for the accident, he would be convicted of reckless driving and intentional collision, and he may be investigated for possible insurance fraud. In addition to the legal consequences, Cueball, Black Hat and Danish may also experience some combination of fractured bones, spinal injury, and brain damage due to the level of force typically imparted on both cars in such crashes. In short, this is much more physically and legally hazardous for Black Hat than popular perception tends to believe.

==Transcript==
:[Black Hat is driving, and Danish, who seems to be his equal, is in the passenger's seat. They are closely followed by some other vehicle.]
:Black Hat: That guy's tailgating me.
:Danish: I'll take a look.

:[A car is shown to be closely behind Black Hat's car.]
:Danish: His laptop's running, probably in the back seat. And... yup, the WiFi autoconnects.

:[Close-up of Danish using a laptop.]
:Danish: Now we just scan for remote exploits... install speech synth... And take a shot in the psychological dark.

:[Cueball's car.]
:Laptop: Hello.
:Cueball: What? Who's there?
:Laptop: She'd be alive if it weren't for you.
:Cueball: ...Oh God.

==Trivia==
This may be a continuation of [[433: Journal 5]], with Black Hat taking Danish to the "date" that was mentioned.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Black Hat]]
[[Category:Comics featuring Danish]]

Talk:2388: Viral Quiz Identity Theft

2020-11-22T15:53:01Z

Gertuviti: Explain the meaning of a quote for BlackHat

I was going to add in the old, old example of constructing your 'pornstar name' of first pet's name and (road you grew up on|mother's maiden name), but I see there's no real agreement which of the latter it is when I wanted to get it straight for editing in. MMN is probably better for "security question" purposes, but it predates The Eternal September anyway, before which it was more a party-thing rather than a security threat against BBS/Usenet/mailing-list users. [[Special:Contributions/162.158.159.132|162.158.159.132]] 00:57, 21 November 2020 (UTC) (a.k.a. Frazier Derwent)
: I briefly googled 'eternal september' and found it was a date when internet dialogue was swamped by new users. How did this relate to security questions? [[Special:Contributions/108.162.219.248|108.162.219.248]] 12:08, 21 November 2020 (UTC)
:: It's a reasonable lower limit on when internet commerce became 'a thing' (and a large enough pool of potential marks, with everyday household access and not institution/corporate, to make it a profitable scattergun tactic). Though I'd have said a little bit later myself, there was no such obvious spike in potentially naive users as lucrative targets such as online banking started to be a thing. (And attack vectors tended towards things like malware-based login-scrapers in that era, in my experience.) Prior to then, though, any spear-phishing (not yet known by that name) would have been unlikely to have been achieved through the Porn-name Game, online, though perhaps it'll have been taken advantage of if brought up as an entertainment/ice-breaker at a physical social gathering, for traditional 'meatspace' fraud and personation crime, opportunistically. [[Special:Contributions/162.158.154.83|162.158.154.83]] 15:21, 21 November 2020 (UTC)

Hairy tries to do something only to find that Black Hat did it far more efficiently - https://xkcd.com/1027/

Hmm... what exactly is the purpose/meaning of this sentence?

<blockquote>Even though White Hat is correct that there are public databases with lists of legal names and addresses, lots of online interactions take place in forums where people adopt pseudonyms.</blockquote>

I understand that the second part has to do with a strategy for doxing, which is fine, but why would it be appendaged to White Hat's strategy like that (and especially with an 'even though')? The entire paragraph following is just a description of how one could use this to attack the participant, but the whole point of the comic was to show that a brief Google search could give you the same results. If anyone could clear that up, it would be helpful. [[User:BlackHat|BlackHat]] ([[User talk:BlackHat|talk]]) 13:44, 22 November 2020 (UTC)
: As you mentioned, White Hat's basic argument is there are already public databases of names and addresses. If that's all the information Hairy needs, then Hairy's more elaborate scheme is unnecessary. The quote you mention is a counterargument to White Hat's point: If Hairy is actually trying to steal the identity of some *specific* online users and all Hairy knows is a pseudonymous username like e.g. turnitup91, then Hairy can't find out anything more about them from the public databases alone. Hairy's more elaborate scheme may actually make sense in such a case.
:
: And that's the purpose of the quote: Even though White Hat is correct about the public databases, that's not enough if you're trying to de-anonymize someone specific and all you have is a pseudonym. [[User:Gertuviti|Gertuviti]] ([[User talk:Gertuviti|talk]]) 15:53, 22 November 2020 (UTC)

Talk:2365: Messaging Systems

2020-09-29T12:57:34Z

Gertuviti: Answering the question from 162.158.158.225

I guess ordinary email should be in the same section as SMS as well. [[Special:Contributions/162.158.158.171|162.158.158.171]] 00:20, 29 September 2020 (UTC)

The comic should mention MMS, which is well integrated into SMS, so that it's supported by not quite as much as SMS but still by almost everybody, and counts as vaguely modern in that you can attach images and have no length limit. ―[[User:TobyBartels|TobyBartels]] ([[User talk:TobyBartels|talk]]) 00:46, 29 September 2020 (UTC)

My DynaTAC doesn't get SMS. --[[Special:Contributions/172.69.22.150|172.69.22.150]] 00:56, 29 September 2020 (UTC)

Okay, got a basic explanation up; The comic is missing a bunch of different messaging services I feel. Also, I knew that somebody would say that their phone doesn't support SMS, I guess that habit of hedging writing with mostly is paying off.
[[Special:Contributions/172.69.63.143|172.69.63.143]] 01:01, 29 September 2020 (UTC)

"It [Whatsapp] is popular in multiple countries, namely Latin America and India." I have no idea what this means: should "namely" be "mainly"? But is the fixed version even true? [[Special:Contributions/162.158.158.225|162.158.158.225]] 11:28, 29 September 2020 (UTC)
: Both "namely" and "mainly" are valid and mean very similar things in this context. Saying "... mainly Latin America and India" suggests most of Whatsapp's popularity is in Latin America and India and Whatsapp has little popularity anywhere else. On the other hand, saying "... namely Latin America and India" suggests that Latin America and India are some of the countries where Whatsapp is particularly popular without implying that Whatsapp is significantly unpopular elsewhere. That said, it's a pretty subtle distinction that almost no one will actually care about except hardcore language geeks. With love from your friendly neighborhood Grammar Communist. <3 [[User:Gertuviti|Gertuviti]] ([[User talk:Gertuviti|talk]]) 12:57, 29 September 2020 (UTC)

Discord is slowly moving towards supported by everyone because of Covid-19. [[User:Stardragon|Stardragon]] ([[User talk:Stardragon|talk]]) 12:27, 29 September 2020 (UTC)