https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=172.70.86.54&feedformat=atomexplain xkcd - User contributions [en]2024-03-29T07:12:08ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=2854:_Date_Line&diff=3289262854: Date Line2023-11-14T09:59:40Z<p>172.70.86.54: /* Explanation */</p>
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<div>{{comic<br />
| number = 2854<br />
| date = November 13, 2023<br />
| title = Date Line<br />
| image = date_line_2x.png<br />
| imagesize = 443x522px<br />
| noexpand = true<br />
| titletext = They estimate the rocket should be free by approximately ... uh ... well, in about two hours.<br />
}}<br />
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==Explanation==<br />
{{incomplete|Created by a SNAGGED LINE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
The {{w|International Date Line}} is a nominal line on Earth near the {{w|180th meridian|antimeridian (180°)}} that marks where travel across will require your clock to be adjusted by a full day (forwards or backwards), give or take the 'normal' time of day adjustment. It is one of three situations where the date might change for you, the usual one being when (in your time zone) you pass from the hour of 11 pm across beyond midnight but also if you travel between any other time zones at such a time (usually being a window of just one hour) where one is pre-midnight and the other post-midnight.<br />
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Most people don't travel at or around midnight, and just being awake as the clocks tick over is not often such a remarkable thing other than to perhaps mark reaching a special date (significant birthdays, perhaps, or {{w|New Year's Day}}), but travel across or between areas of east and west Pacific (or [[503: Terminology|vice-versa]]) is not so uncommon yet comes with it the special need to effectively adjust your watch by a full day (plus or minus any other time to be adjusted).<br />
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The International Date Line is not a physical string,{{Citation needed}} and therefore could not be caught on by a rocket. It should also be noted that the International Date Line is not a straight line, but extends either side of the antimeridian to avoid confusion on internal land journeys (like Russia, {{w|Chukotka Autonomous Okrug|a portion of which}} overlaps the antimeridian), similarly cutting off 'nearby' outlying island territories or adding needless complexity {{w|Tokelau#Timezone|when dealing with chosen trading partners}}.<br />
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Based off where the map shows, the Rocket was most likely launched by the Russians, possibly from the Vostochnyj Cosmodrome. Of course, the odds of a rocket getting stuck on such a line (if it existed) would be incredibly slim. Additionally, striking such an object wouldn’t trap the rocket. Instead, the rocket would undergo what many [[:Category:Kerbal Space Program|KSP]] users have encountered, a Rapid Unplanned Disassembly.<br />
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The title text refers to how this event has temporarily paused time, and to how that means ‘they’ can’t give a time for when it will be fixed. If, say, it was 8:00 when the rocket got snagged, then it is 8:00 until they fix it. This means that no matter how much time passes, until they fix it, it will remain 8:00.<br />
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==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
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:[The earth, with the date line as a physical band being pulled off of the surface by a rocket, cutting into the land on the other side.]<br />
:Caption: Timekeeping announcement: a rocket accidentally became snagged on the international date line during launch. Please pause all clocks and calendars until NASA is able to free it and safely resume the normal flow of time.<br />
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==Trivia==<br />
* '''This trivia section was created by a BOT'''<br />
* The [https://imgs.xkcd.com/comics/date_line.png standard size] image was uploaded with a resolution/size larger than the supposed 2x version.<br />
* This may have been an error.<br />
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{{comic discussion}}<br />
[[Category:Time]]<br />
[[Category:Space]]<br />
[[Category:Calendar]]</div>172.70.86.54https://www.explainxkcd.com/wiki/index.php?title=Talk:394:_Kilobyte&diff=324803Talk:394: Kilobyte2023-10-03T17:26:08Z<p>172.70.86.54: /* What is the source of the "official" definition of the kilobyte? */</p>
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<div>The drivemaker's version here does 'depreciate' their kilobyte, indeed, but rather than based on slipping food-standards (which are often highly regulated) I think this is actually based upon the actual age-old practice of them sometimes using 10<sup>3n</sup> (1,000s, 1,000,000s, etc) measures of byte-multiplies in preference to 2<sup>10n</sup> ones (1,024, 1,048,576, etc) in order to get a better figure. For example 20MB drives (back in the old days, this is) with 971,520 bytes (almost 1Mb, by either measure) ''less'' than the true binary-matching 20MiB value which various computer OSes would work with. (Or a 'binarily' 20MB drive gets advertised as "20.1MB" one.) On the other hand, something that "needs 20Mb of installation space" might have deliberately been given the binary-divisible version of the unit to make it look marginally less resource-hungry than the decimalised measure would have indicated. Minor differences in their own right, on a bad day when the competing standards mesh badly you might find yourself just short of storage space when you thought you'd be Ok.<br />
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Although in real-life the difference between any given unit's interpretation has ''not'' changed, as equipment capacities increases and we start to use increasing degrees of prefix upwards, any discrepancy becomes more significant. 1KB is plus or minus 24 bytes (~2%), 1MB is plus or minus around 48KB (~5%), 1GB is plus or minus 73MB (~7%) and 1TB could be very nearly 100Gb short (~10%). For those that care about these things that's at the very least annoying. Like with CRT monitor sizes that were often more an indicator of tube-end size than the true size of the visible/illuminatable portion, giving them an inch or two less of effective display than you might expect. [[Special:Contributions/178.98.31.27|178.98.31.27]] 13:55, 18 June 2013 (UTC)<br />
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:Just to follow-up to myself, based upon a unit capitalisation discrepancy that I only spotted post-posting, but that I won't bother fixing, there's also the old confusion between "kilobits-per-second" and "kilo''bytes''-per-second" (and mega- and giga- versions, more recently with broadband and more advanced ethernets/etc) when it comes to bandwidths and expected speeds. Although you don't necessarily expect to exactly hit the stated limit (with contentions and collisions and latencies and overheads), getting a factor of 8 less than you might have expected has caught people out before, thinking they're getting a far poorer service than advertised... (Not that this has much to do with the above comic, just saying. And, oh lookie here on my desk. A 28,800 'Sportster' PCMCIA faxmodem card (V34, V32bis) with an XJACK&reg; pop-out socket. Why have I still got that?) [[Special:Contributions/178.98.31.27|178.98.31.27]] 14:16, 18 June 2013 (UTC)<br />
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This table fails to mention, of course, that while a Baker's Kilobyte is 1152 bytes normally, it's 1125 on leap years. [[User:Hppavilion1|Hppavilion1]] ([[User talk:Hppavilion1|talk]]) 23:21, 26 October 2017 (UTC)<br />
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== What is the source of the "official" definition of the kilobyte? ==<br />
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From the article at time of creating this topic: "the official definition now states that 1 kilobyte is 1000 bytes". This is official according to whom exactly? I may have missed a citation somewhere but I think this clause needs a citation in the text of the the article. AzureArmageddon 13:50, 3 October 2023 (UTC)<br />
:Well, SI and IEC either state or 'recomend' that a kilobyte (kB) is 10³ bytes, while tradition has tended to use KB (capital-K) for 2¹⁰ bytes (obviously open for confusion) while IEC defines this as a 'kibibyte' (KiB). There's several possible cites for that, one really would need to decide which look best/official.<br />
:As a general hint to people, though, I think that makes it probably best to just always use explicit KiBs, and mibi/gibi/tebi/etc equivalents, in full or as unit abbreviations, because there might be people who haven't got the memo/don't know whether ''you'' got the memo, otherwise. And at least there's a chance that even those unaware of "FOObibytes" will try to find out what these are... unless they just mistake them for typos or read them unconsciously wrongly, but then there's probably more problems than just assuming the wrong base-multiple... ;) [[Special:Contributions/172.70.86.54|172.70.86.54]] 17:26, 3 October 2023 (UTC)</div>172.70.86.54https://www.explainxkcd.com/wiki/index.php?title=Talk:2821:_Path_Minimization&diff=322489Talk:2821: Path Minimization2023-08-29T04:02:29Z<p>172.70.86.54: </p>
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<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
Judging from the angle of the arms, I do not believe that the swimmer is in distress. In fact I think the swimmer is just a future projection of Cueball, not a separate person.<br />
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:I agree that the swimmer does not appear to be in distress, although the title text suggests that it is probably a separate person.<br />
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:My personal interpretation is that the situation is "meeting a friend at the beach to get ice cream". Options are either a) meet the friend first and then swim back to get ice cream or b) get ice cream first and take it out to eat together in the water. [[Special:Contributions/172.70.86.54|172.70.86.54]] 04:02, 29 August 2023 (UTC)<br />
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Technically, the path that minimizes swimming passed a nearby boat rental stand. (by the way, I didn't write the unsigned paragraph above this one) [[Special:Contributions/172.69.247.40|172.69.247.40]] 03:05, 29 August 2023 (UTC)</div>172.70.86.54https://www.explainxkcd.com/wiki/index.php?title=Talk:2586:_Greek_Letters&diff=227714Talk:2586: Greek Letters2022-02-28T10:28:13Z<p>172.70.86.54: Reference of uppercase phi to Strange Planet comics</p>
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<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
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Pi also shows up in lots of extremely advanced equations as pi, not as something else, adding edit. 123.456.7890<br />
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zeta_0 is also used for the first transfinite ordinal that is unreachable through addition, multiplication, exponentiation, and epsilons subscripting. EDIT: phi is used for the Veblen hierachy. [[User:GcGYSF(asterisk)P(vertical line)e|GcGYSF(asterisk)P(vertical line)e]] ([[User talk:GcGYSF(asterisk)P(vertical line)e|talk]]) 05:11, 26 February 2022 (UTC)<br />
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Don't you have an English saying: '''simple/easy as π'''? [[User:Nukio|Nukio]] ([[User talk:Nukio|talk]]) 05:51, 26 February 2022 (UTC)<br />
:the saying is '''easy as pie''' as in the dessert. sometimes we write it '''easy as π''' as a nerdy joke. [[Special:Contributions/162.158.107.230|162.158.107.230]] 08:08, 26 February 2022 (UTC)<br />
:: sqrt(-1) 2³ Σ π and it was delicious [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 08:30, 28 February 2022 (UTC)<br />
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Related: https://xkcd.com/2520/ [[Special:Contributions/162.158.103.224|162.158.103.224]] 08:59, 26 February 2022 (UTC)<br />
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I've found a use for capital Xi: https://en.wikipedia.org/wiki/Harish-Chandra%27s_%CE%9E_function that seems to be from the field of Harmonic Analysis. [[User:Douira|Douira]] ([[User talk:Douira|talk]]) 14:50, 26 February 2022 (UTC)<br />
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The part that says the farad is "unusually large" is incredibly biased IMO. On the scale of planets its "unusually small", In fact, on the scale of EV's its even pretty normal. The writer is only considering small electronic circuits. Also the Henry is very well scaled to the Farad so how "unusual" is it really? [[Special:Contributions/108.162.241.33|108.162.241.33]] 17:13, 26 February 2022 (UTC)<br />
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:Apologies for the incredible bias. You're right in saying that I'm only considering small electronic circuits; I haven't worked on power distribution systems or applications with large capacitor banks, so my only hands-on experience of components measured in whole farads would be supercapacitors. In consumer electronics, where capacitors are typically labelled in pico, nano or microfarads, the whole farad is rarely encountered. I do still think that capacitors are a good counter-example of items using Mu that you can see and touch, in so many modern electronic devices. But as my previous use of language was so divisive, I'll let someone else attempt to reintegrate the point, if they feel it's useful. [[User:Kazzie|Kazzie]] ([[User talk:Kazzie|talk]]) 16:11, 27 February 2022 (UTC)<br />
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Isn't the ''capital'' psi used for the wavefunction? [[User:GcGYSF(asterisk)P(vertical line)e|GcGYSF(asterisk)P(vertical line)e]] ([[User talk:GcGYSF(asterisk)P(vertical line)e|talk]]) 19:35, 26 February 2022 (UTC)<br />
:Yes, but rarely. The lowercase ψ is much more common (AFAIK it dates back to [https://commons.wikimedia.org/wiki/File:Grave_Schroedinger_(detail).png Schrödinger himself].<br />
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How sad that there is no '''η'''! Missed chance to blame steam machine engineers for not trying harder to invent the perpetuum mobile. --[[Special:Contributions/172.70.242.177|172.70.242.177]] 20:01, 26 February 2022 (UTC)<br />
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The lowercase epsilon is used much more often for something else - usually to denote that the "variable" on the lefthanded side is a member of the "set" of the righthanded side of the lowercase epsilon. Of course, this is totally unimportant ;-).<br />
:You are referring to the "element of" sign, which is distinct from lowercase epsilon (although based on it).<br />
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I highly doubt that the use of Ξ has anything to do with it "looking like a UFO." Rather, I'd suggest it's because it's essentially never used, at least among the English speaking mathematicians in the US, and probably Europe. [[User:Douira|Douira]] went out of their way to find an example, and found something increadibly obscure, which supports the point. ''Why'' Ξ is rarely used is another question. Maybe because it could easily be confused for an E or Sigma, with lazy handwritting? Maybe because it's a Greek letter without a direct Latin counterpart, so doesn't correspond with the first letter of any common words? [[Special:Contributions/162.158.63.49|162.158.63.49]] 22:50, 26 February 2022 (UTC)som<br />
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In my experience lower case eta, zeta, (and xi) most commonly show up as dummy variable in an integral. Any two may be used for a double integral and all three for a triple. Double and triple integrals are often quite terrifying, particularly when somebody cannot write all three symbols consistently and distinctly, so many integrals become "integral squiggle squiggle dee squiggle dee squiggle".[[Special:Contributions/172.70.174.219|172.70.174.219]] 10:10, 27 February 2022 (UTC)<br />
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π is also commonly used as the [https://en.wikipedia.org/wiki/Prime-counting_function prime-counting] function in number theory. Most problems regarding primes are usually considered hard, like the twin prime conjecture.<br />
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Lower-case sigma is also used in sigma-algebras, which is part of the theoretical background underlying statistics, among other things. I second that the lower-case epsilon drawn by Randall is the lunate variant that looks indistinguishable from the "is an element of" symbol and should probably get mentioned. On an unrelated note, there's a story of someone using capital xi at a math conference specifically to annoy some other mathematician who *really* didn't like them. [[Special:Contributions/172.70.211.26|172.70.211.26]] 20:30, 27 February 2022 (UTC)<br />
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Alpha is also used in aeronautics for the angle of attack of the airflow over a wing. Exceeding a critical angle of attack leads to an aerodynamic stall, which has been cause of many fatal accidents.<br />
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Uppercase phi looks like an obvious reference to [https://twitter.com/nathanwpyle/status/1178152201392447488| this comic and author], as he normally uses the term orb to refer to spheres and balls (as part of the intrincate language of the characters), besides he normally uses that typographic resource of writing a word with its letters separated by spaces, i.e.: e x p e r i e n c e, in the example link. I'm missing the math context on why refering to orbs for uppercase phy, but it could be just because due to the form of the character. [[Special:Contributions/172.70.86.54|172.70.86.54]] 10:28, 28 February 2022 (UTC)</div>172.70.86.54