explain xkcd - User contributions [en]

1622: Henge

2022-01-08T06:14:12Z

172.69.68.200: it [in] a

{{comic
| number = 1622
| date = December 28, 2015
| title = Henge
| image = henge.png
| titletext = I've got the Craigslist post ready to go! I wasn't sure what category it should go in, so I listed it as property and put that it has 'good sun exposure.'
}}

==Explanation==
[[Ponytail]] and [[Cueball]] walks in from the left to meet [[Megan]] who comes from the right. They are walking in between two trees while Ponytail tells Cueball that ''One day a year, the sun sets directly between these two trees.''

Cueball's reply: ''Oh, cool - like the Manhattan thing'', is a reference to {{W|Manhattanhenge}}, a phenomenon occurring twice a year that causes the setting sun to align with the east-west streets of the main grid of {{w|Manhattan}}, {{W|New York City|New York}}, causing a very special light display. Manhattanhenge is itself named after {{W|Stonehenge}}, an ancient monument consisting of several large stones, where the heel stone and the embanked avenue are aligned to the sunset of the {{W|winter solstice}} and the opposing sunrise of the {{W|summer solstice}} (thus creating on purpose the effect seen today in Manhattan, on specially intended dates). Hence the title of the comic, which was released less than a week after the winter solstice which fell on 2015-12-22.

After a beat panel Cueball, however, realizes that one could make the setting sun line up with almost any two arbitrary trees on any given day. This is due to the fact that the trees are effectively zero-dimensional points on the surface rather than one-dimensional lines like street grids. So any two trees that are close together with one tree further north would allow a setting sun to set between them; the viewer of the sunset could simply move themselves to make the alignment work. This is opposed to Stonehenge/Manhattanhenge, which requires the sun to align with a straight line, and only works on a few days a year.

The twist comes when Ponytail and Megan actually attempt to capture the setting sun with a {{w|butterfly net}}, as it is revealed that the sun is somehow setting at the actual point between the two trees rather than behind the trees when viewed from the east side. This is of course not possible in real life,{{Citation needed}} but in the comic's last panel and in the title text the girls continue with their successful though surrealistic plan.

If this was indeed our {{w|Sun}} that they had somehow shrunk and cooled enough to captured with a butterfly net, transfer to a bag and bring it home, this would on xkcd terms be no more strange than many of the strange [[:Category:Strange powers of Beret Guy|powers]] of [[Beret Guy]]. If this would indeed happen, then since {{w|Earth}} and the rest of the {{w|solar system}} is now missing its central star there would be a ton of problems for everyone on Earth. So the girls would probably be able to get a lot of money in ransom for releasing the sun, but in the title text it turns out that they are just going to sell the Sun on-line.

Alternatively this is not ''the'' Sun, but just a small sun-look alike, maybe a {{w|ball lightning}} which might actually be able to behave like this (though one would not be able to capture it in a bag).{{Citation needed}}

Or the girls simply play a theatrical show for the reader. They know the comic's panel orientation, reader's position and the view projection. So they position themselves like the two trees between reader and the distant sun to look like they capture it with a butterfly net and a bag.

The title text refers to {{w|Craigslist}}, a web site where the girls plans to offer the sun for sale in hopes of getting rich. Craigslist is a {{w|classified advertisements}} website with sections devoted to jobs, housing, personals, for sale, items wanted, etc. One of the girls tells that she was uncertain as to under which category she should list a "Sun for sale". But she put it under property (as in real estate). To advertise the "property" she put "''that it has 'good sun exposure''", a common description of real estate. Being the sun itself you could claim that it is well located compared to the Sun, but it will never really see any sun light itself as the only "sun" light that hits the Sun is the light from other stars which is very dim.

The title text may also be a reference to a woman who was stopped by eBay after attempting to sell plots of "land" on the Sun on the site.

Lately [[Randall]] has had his characters catch several things (but [[:Category:Butterfly net|never butterflies]]) with a butterfly net. The next instance of butterfly nets can be seen in [[1635: Birdsong]], released less than a month after this comic's release date, wherein a bird is chased with a net.

==Transcript==
:[Ponytail and Cueball are walking towards two trees from the left (Cueball has just passed the first tree) and Megan is walking towards them from the right. Ponytail spreads her arms while talking.]
:Ponytail: One day a year, the sun sets directly between these two trees.
:Cueball: Oh, cool - like the Manhattan thing.

:[Beat panel without a frame border. Cueball stands alone.]

:[Cueball looks at Ponytail and Megan, while shining light appears at the top of the frame. Ponytail walks straight under the light looking up and Megan standing to the right looks up and points at the light.]
:Cueball: Wait, isn't that true every day for pretty much any two trees?
:Megan: Shh, here it comes!

:[Cueball lifts both arms up and look on as Ponytail bending back suddenly holds a butterfly net up towards the "setting" sun that approaches the net while Megan is holding a bag open. Both are looking at the sun.]
:Cueball: Wait, what?
:Ponytail: OK, got the bag?
:Megan: Yup, grab it!
:Ponytail: We're gonna be ''rich!''

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Megan]]
[[Category:Astronomy]]
[[Category:Butterfly net]]

83: Katamari

2022-01-03T23:52:49Z

172.69.68.200: /* Trivia */ added another comic with a reference to Katamari, but there's already a page for that... huh.

{{comic
| number = 83
| date = March 31, 2006
| title = Katamari
| image = katamari.jpg
| titletext = As the King of All Cosmos remarked, 'Is it that it's fun, or that it lets you forget yourself?'
}}

==Explanation==
{{w|Katamari Damacy}} is a Japanese game in which the player must roll around an infinitely sticky katamari ball, cottoning up objects and terrain to increase the ball's size. In this comic, [[Cueball]] uses the katamari as an analogy for his love for [[Megan]], pushing it to such embarrassing extremes that Megan feels the need to remark whether he could "possibly get any gayer." At this point, Cueball wins the level he is playing and is transported by a "Royal Rainbow," an in-game occurrence at the completion of each level. The rainbow is a symbol of gay pride, in addition to being just a generally happy (i.e. gay) idea.

Cueball also only takes up such a stand after Megan requests that he help her. This is possibly a criticism of male selfishness (perhaps Randall's self-criticism), in that males do not discuss romantic ideas, except as a way out.

The ''King of All Cosmos'', mentioned in the title text, is an instructive character in all of the Katamari games. The title text points out that perhaps we either like or love video games not because they are fun, but because they let us forget our problems and retreat into someone else or an intricate fantasy.

==Transcript==
:[Megan stands on the left. Cueball is sitting on the floor with a game controller in his hand. He is looking at a TV on the floor connected to a game console, also on the floor.]
:Megan: Can you pause for a moment and help me with something?
:Cueball: You know, our love is like a katamari. We travel along, rolling up more and more of the world into our shared experience, taking it and making it our own.

:Megan: I, you... wow. Geekiness aside, that was actually incredibly sweet.
:Cueball: The clutter of everyday life, with a simple core to tie it together, eventually becomes something grand as the world itself.

:[A rainbow extends outward from the TV, with "ROYAL RAINBOW!" above it. Cueball raises his hands in victory.]
:Megan: Okay, also sweet, but now I'm wondering if you could possibly get any gayer.

==Trivia==

Katamari Damacy is also a subject of [[161: Accident]] and [[851: Na]].

{{comic discussion}}
[[Category:Comics with color]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]
[[Category:Video games]]
[[Category:Katamari Damacy]]
[[Category:Romance]]
[[Category:Comics with lowercase text]]

1549: xkcd Phone 3

2021-12-26T17:53:54Z

172.69.68.200: fixing link

{{comic
| number = 1549
| date = July 10, 2015
| title = xkcd Phone 3
| image = xkcd_phone_3.png
| titletext = If you're not completely satisfied with the phone after 30 days, we will return you to your home at no cost.
}}

==Explanation==
This is the third entry in the ongoing [[:Category:xkcd Phones|xkcd Phone series]] which parodies common smartphone specs by attributing absurd or useless features to a fictional phone that sounds impressive but would actually be very impractical. The previous comic in the series [[1465: xkcd Phone 2]] was released over half a year before this one and the next [[1707: xkcd Phone 4]] was released almost a year later.

;2 AA batteries (not included)

:A phrase usually shown on small, low-powered, electronic devices like remote controllers, and not on cellphones; which use lithium-ion batteries and need to be periodically recharged for continuous use.

:The apparently thin phone (according to the scale as judged by the wristband) would also preclude inserting AA batteries, unless a protruding battery compartment is hidden out of view on the back of the phone.

:Alternatively could mean two Anti-Aircraft (artillery) "batteries" which would be groups of light or medium artillery pieces or missiles (2 to 9 weapons per battery, depending on country, weapon system and organization). In any case, they would badly hamper the portability of the phone.[[[285: Wikipedian Protester|''citation needed'']]]

;Boneless

:Reference to meat or fish products being boneless, i.e. having all the bones removed, making it convenient to cook or eat. Phones do not typically have bones{{Citation needed}}, so this is wholly unremarkable. A possible reference to the iPhone 6's reported problems with its chassis, where it {{w|IPhone 6#Bendgate (chassis bending)|could bend under pressure}}.

:Likely a reference to "Bone Conduction Microphones" implying that needing bones to work is a disadvantage and this phone has the feature of being "Boneless".

:[[xkcd Phone 4]] was instead "seedless".

;Ear screen

:An overcomplicated term for a speaker, connecting a screen which emits light to send visual information and the portion of a speaker which vibrates to send auditory information. Comparing the two makes a speaker a screen for the ear.

:Could also be implying that there's a screen protecting the user's ear from the phone's internals, or the reverse.

;Heartbeat accelerator

:A mashup of heartbeat sensor and accelerometer. May be some sort of external pacemaker. If that's the case, it's worrying that it only accelerates, potentially causing a positive feedback (heart attack). It may also be the result of the phone being so exciting or frustrating that it increases its user's heart rate.

;MobilePay money clip

:While mobile pay is a form of payment involving electronic transfers via cellphone, this model includes a money clip; a way of holding physical bills together, which defeats the purpose of electronic payment. Because you can take cash wherever, this is a "MobilePay" using physical money.

;Siri, or whoever it was we put in here

:A joke on intelligent personal assistants. It also hints that Siri and the like are actual people, trapped inside of phones, which is not the case{{Citation needed}}.

;Instead of being on surface only, screen goes all the way through

:A reference to surface screens. Possible reference to smartphones with screen display wrapping one or more edges, like Samsung Galaxy Note Edge or Samsung Galaxy S6 Edge, or dual-screen smartphones with screen on the back (usually e-ink) like YotaPhone 2, or smartphones with minimal bezel like e.g. Sharp AQUOS Crystal.

:Screen going ''all the way through'' would leave no place for innards of smartphone: processor, battery etc., and unless each layer is designed to be semi-transparent to see the inner {{w|voxel}}s the inner displays would be unseeable anyway.

;theknot.com partnership - phone licensed to perform wedding ceremonies and does so at random

:[https://www.theknot.com/ theknot.com] is a website that assists in all stages of wedding planning. Due to this partnering, the phone has apparently obtained legal status as a {{w|Justice of the peace}} capable of performing legally valid marriages. It exerts this capability randomly, however, so the phone's owner (or potentially any other unsuspecting bystander) could suddenly find themselves with a new spouse without their knowledge, generally an undesired effect{{Citation needed}}. Whether this would result in unintentional {{w|bigamy}} or if the phone restricts itself to pairing up singles, or even enacts divorce first if necessary, is left unclear. May be a reference to how same-sex marriage was fully [http://en.wikipedia.org/wiki/Obergefell_v._Hodges legalized] in the United States just two weeks prior to the release of this comic.

;Fingerprint randomizer

:Presumably randomises the user's fingerprint, which may or may not be inconvenient depending on the intent of the user. It is not clear whether the device will change the person's fingerprint into a human-like fingerprint that is randomly selected from all possibilities, or if it completely mangles the fingerprint of the user. Either way, physically altering the user's finger to this degree will likely involve a painful process. Likely a cynical reference to fingerprint scanners, which are touted as password replacements.

;USB E (hotswappable)

:A USB port that makes fun of the three current systems, A, B, and recently C, by skipping D completely and jumping to E. The port presumably charges the phone and allows to transfer files like normal, but this kind lets you perform {{w|Hot swapping}} (replacing computer system components without turning the system off) with it, which has always been a feature of USB, so mentioning it is redundant at best.

:May be a reference to the eSATAp (Power over eSATA) hybrid port that is functioning as a USB and eSATA port at the same time. The Serial ATA bus interface has standardized hot swapping support.

;Waterproof, but can drown

:Perhaps a reference to Siri or the person trapped in the phone drowning, but the phone itself staying functional. This is another human-like function, which the first 2 XKCD Phone comics had.

;Foretold by prophecy

:Likely mocking people on the internet who attempt to predict when Apple will release their next device. Might also be a joke on many videogames or fantasy novels, in which the main character is 'the chosen one', because 'the prophecy' foretold it.

;Runs Natively

:Usually a description given to ported software, as this statement doesn't make any sense when referring to hardware (notable {{w|Transmeta Crusoe|exceptions}} to the norm are few and far between). When software writers would like to run their apps on multiple platforms, they usually have three choices: re-compile the source code into each platform's codebase (often requiring tweaking to handle practical differences in resources between the systems); use a specially 'pre-portable' code that you can {{w|write once, run anywhere}}, such as Java, but requires a suitable interpreter to be written for each platform (and may still require code tweaks to absorb differences in implementations); create a specific emulator/virtual machine to allow existing code to 'see' the platform it was written for, despite the underlying system.

:Only the first option is 'running natively', often the most optimised and thus best-performing option, and is usually qualified such as "Runs <Software Name> natively", for particular packages full compiled upon that platform. It would also make little sense for the OS ''itself'' to be non-native, except when intentionally emulating another system (ideally on a more powerful system that can power past the inefficiencies of conversion and translation).

:Or, in this case, it may be that the phone has legs and can literally run.

;Wristband

:Probably mocking trending smart watches, this feature would not be very useful on a full-sized smart phone, as it would be uncomfortable to wear due to its size. Also possibly a follow-up to xkcd Phone 2 being described as a 'phone for your other hand', as the wristband would make it possible to have all three phones accessible at once.

;Wireless discharging

:Some modern smartphones use a system called "wireless charging," in which power is delivered to the phone without a wire. This phone, however, uses wireless technology to discharge the phone, which would be useless given that the phone needs power and removing power from its battery doesn't seem to help... May also refer to the standard behavior of the phone's antenna, which communicates wirelessly via EM radio waves, but discharges the battery in doing so. It could also be simply and literally describing the nature of all cell phones, and indeed all battery-powered electronic devices, to gradually use the battery (discharging) when there are no wires attached (wireless), since wireless also means no power cord is plugged in (and assuming the absence or non-use of the aforementioned wireless charging function, which this phone may not even have). Depending on the avenue of discharge, this may also be related to the heartbeat accelerator, accelerating the user's heartbeat by shocking them. Notably, a few recent flagship phones now have a built in Qi wireless charging pad, so other devices can charge from its battery; this is usually marketed as power-sharing but could also be called wireless discharging.

;Magnetic stripe

:Likely a dig at the NFC (near-field communication) wireless radio modules in many modern phones. NFC allows, among others functions, mobile payment. This magnetic stripe could be a cheap way to imitate payment functionality, but "compatible" with classic credit cards.

:Magnetic stripes are a data storage method used by devices such as credit cards and key cards to hold and transfer small amounts of information like key codes. Usually cellphones don't have them as they utilize more robust and protected ways to store and transmit data (such as NFC). The magnetic stripe shown would likely be unusable with current magnetic stripe readers due to the phone's thickness, in contrast to that of regular cards, thus breaking all imagined 'compatibility' arguments.

:It would also be very annoying as it seems to block part of the screen.

:However, some modern phones actually have {{w|Magnetic secure transmission}} which allows them to interface wirelessly with magstrip readers by simulating the magnetic field from a passing magnetic stripe.

The phrase "We made another one®©™" is a reference to how phone companies release new phones very often, and the trademarks that surround the phone itself.

The title text is a joke on guarantees and customer service. Usually the advertisement says that if the customer is not satisfied with the product, they'll refund the money and take the product back at no additional cost. In this case they guarantee the customer they'll send him/her home without charge; implying they won't fix or refund anything. Or that due to anticipated but unspecified faults of some kind, the phone's owner will ''need'' help to get back home when things go wrong, and probably be thankful for such assistance, in yet another example of a worryingly non-specific 'reassurance'.
In addition, it says it would do so only AFTER thirty days, as opposed to the usual thirty-day return guarantee, which means you may be stuck with your phone for a month until you can be taken home yourself.

==Transcript==
:[An image of a smartphone lying down, with many labels pointing to it. There is a black stripe across the top left corner of the phone. At the top right something is protruding from the side, like a volume control. There is a wrist band (only partly shown) attached to the middle of each side of the phone. Above the screen are several small features, below only a central square and on the bottom a socket. Clockwise from the top left the labels read:]
:2 AA batteries
:(not included)
:Boneless
:Ear screen
:Heartbeat accelerator
:MobilePay money clip
:Siri, or whoever it was we put in here
:Instead of being on surface only, screen goes all the way through
:theknot.com partnership: Phone licensed to perform wedding ceremonies and does so at random
:Fingerprint randomizer
:USB E
:(hotswappable)
:Waterproof, but can drown
:Foretold by prophecy
:Runs natively
:Wristband
:Wireless discharging
:Magnetic stripe

:[Below the phone:]
:Introducing
:<big><big>The xkcd Phone 3</big></big>
:We made another one®©™

{{comic discussion}}

[[Category:xkcd Phones]]
[[Category:Comics sharing name|xkcd Phones]]
[[Category:Virtual Assistants]]

236: Collecting Double-Takes

2021-12-21T05:13:49Z

172.69.68.200: /* Explanation */

{{comic
| number =236
| date =March 16, 2007
| title =Collecting Double Takes
| image =collecting_double_takes.png
| titletext =Fun Game: find a combination of two items that most freaks out the cashier. Winner: pregnancy test and single coat hanger.
}}

==Explanation==
There's a fairly well-founded meme that singles looking for other singles (''mostly'' that being men for women, and vice-versa, but not exclusively) can make connections with others in the fresh produce sections of a supermarket. From a single lady's point of view, men who are buying such goods are more likely to be unattached, due to the traditionally skewed gender politics of who shops for what in a couple, and at the same time, the man is exhibiting good habits in not merely stocking up on ready-meals or subsisting on takeaways while living the bachelor life.

By standing in a produce aisle with a tube of {{w|K-Y Jelly}} (which is most commonly used as a sexual lubricant) in his hand and considering what produce to buy (between bananas, apples, oranges, zucchinis, and doubtless many more off-screen), [[Cueball]] is allowing other people to believe that he either has plans to have sex with any connection he might manage to take home with him, or also he plans to use the chosen produce item to pleasure himself, probably sexually.

Cueball is probably not actually planning on doing either{{Citation needed}}, but he loves to see the look on people's faces; hence, he's collecting double-takes.

In the title text, he says he likes to play a game of "freak out the cashier using two items." Wire coat hangers have been used to perform {{w|Unsafe abortion | do-it-yourself abortions}}, many times with disastrous effects, such as internal hemorrhaging and the death of the woman and the living human inside her.

==Transcript==
:[Cueball is standing in the middle of the produce aisle in a supermarket, holding a tube of K-Y Jelly in one hand, the other on his chin. The signs read "Bananas" "Apples" "Oranges" and "Zucchini" from left to right.]
:MY HOBBY: Standing in the supermarket's produce section holding a tube of K-Y Jelly, looking contemplative.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:My Hobby]]
[[Category:Comics with color]]
[[Category:Sex]]

Talk:2555: Notifications

2021-12-20T01:50:51Z

172.69.68.200:

I wrote that the time in the title text does not seem to have any special meaning, the only thing a quick google search gave me was the bible verse "Think not that I am come to send peace on earth: I came not to send peace, but a sword." which is irrelevant to the comic as far as I can tell. Is there something I missed? -- [[User:256.256.256.256|256.256.256.256]] ([[User talk:256.256.256.256|talk]]) 08:52, 16 December 2021 (UTC)
:I assume it has something to do with time zones, but not sure.[[Special:Contributions/162.158.222.123|162.158.222.123]] 09:40, 16 December 2021 (UTC)
::Yes for sure, it is late in the recipients time zone. And thus the program asks if the notification is so important at this later hour. On the internet you are often in communication with someone in another time zone. Has updated explaination.--[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:17, 16 December 2021 (UTC)
:::But it doesn't have a special meaning. 10:32 or 10:41 would have done the same job. --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 07:15, 17 December 2021 (UTC)

Is it just a weird coincidence that today’s smbc is also about how to stop a tedious conversation? {{unsigned ip|198.41.238.107}}
:It sure is funny. The [https://www.smbc-comics.com/index.php SMBC] comic from 2021-12-15, [https://www.smbc-comics.com/comic/econs Econs], was about paying someone to stop with a boring discussion. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:21, 16 December 2021 (UTC)

I got to thinking about the difference from saying "I perceive that you have mistaken me for someone who cares", or very often "someone who gives a (vulgar word)". I suppose the difference is that talking about Notifications means "Not just now" or "That's enough for now", but you could just say that. It doesn't forbid continuing the subject later. Robert Carnegie rja.carnegie@gmail.com [[Special:Contributions/162.158.159.105|162.158.159.105]] 11:15, 16 December 2021 (UTC)

Are you sure Cueball is sending notification to White Hat? When I saw this comic I thought that White Hat wants to say it annoys him when someone ignores others notifications settings and, voilà, Cueball just does it the same moment. [[User:Tkopec|Tkopec]] ([[User talk:Tkopec|talk]]) 12:58, 16 December 2021 (UTC)
:Well, if White Hat is complaining about anything like that (we never even get a hint what) it should be more about those who sets to ignore notifications (what Cueball does) or else it is about those who set about to ignore others' "ignore-notifications" settings but then he turns out not to be that kind of annoying person, as he actually respects that situation.
:Whether Cueball knows what is about to be (re)complained about, from hearing this tiraid multiple times, I don't know. Or maybe it was mentioned as the pre-"...another thing" spouting of opinion, and thus quickly inspired him to act upon the suggestion.
:It doesn't really matter. Whatever Randall might have conceived as being said before/after the short slice of Whitehat's rant, he gives no direct clue so it's likely to just be a generic stream of opinionated verbosity, making Cueball even more clever and inspired to have discovered this 'life hack' to cut it short. A bit like telling Sheldon that something is a "non-optional social convention".
:...incidentally, one of John Finnemore's radio sketches in his 'Souvenir Programme' series (if you can, look it up (the whole series!) to listen to - I'm sure xkcders would be prime candidates to enjoy, or at least be able to appreciate, the (over?)intelligent humour) was basically if the Russian Revolution were being organised via email, with one character's involvement being (mostly!) a bog-standard Out Of Office reply. Best listened to, although if you can't you can definitely find a script-transcript site or two with the right Google-Fu. [[Special:Contributions/172.70.86.22|172.70.86.22]] 13:46, 16 December 2021 (UTC)

I don't think it's necessarily "past their bedtime"; that's an oversimplification. I think it's implying "they need to go home, prepare for bed, and hopefully get a full night's sleep by the time they have to get up in the morning." It might easily be that they're fifteen minutes from home and want to go to sleep by 11:00 PM. It also might not be their "normal" bedtime; they specifically have "a thing" early tomorrow, an important event which presumably isn't a normal occurrence.[[Special:Contributions/172.70.35.70|172.70.35.70]] 20:01, 16 December 2021 (UTC)
:10:34 is time which can easily be past "normal" - meaning, week day - bedtime and at the same time not that late on party or other social activity. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 00:30, 17 December 2021 (UTC)
::Sure, it ''could'' be past their bedtime, but you're making an assumption. People prefer different amounts of sleep, have different regular schedules, consider different times "early", etc. It's not necessarily true that it's past their normal bedtime, so the explanation shouldn't make that unfounded assumption.[[Special:Contributions/172.70.42.129|172.70.42.129]] 05:37, 19 December 2021 (UTC)

Joke's on White Hat, I put my phone in airplane mode at night. Ain't no notifications waking me up except my alarm. [[Special:Contributions/162.158.106.53|162.158.106.53]] 05:38, 17 December 2021 (UTC)
:...but it's also likely to have flown away, surely? ;) [[Special:Contributions/172.70.86.22|172.70.86.22]] 11:56, 17 December 2021 (UTC)

I don't have the time nor care to fix it myself, but this explanation acts as if Cueball and White Hat are in the same timezone, but "10:34 PM" could mean the same thing "Good Morning" means in XKCD 448. [[User:Tsumikiminiwa|Tsumikiminiwa]] ([[User talk:Tsumikiminiwa|talk]]) 20:39, 17 December 2021 (UTC)

Does anyone know what time #2555 was posted to xkcd.com? It would be entertaining if it was near 10:34pm in Randall's time zone.

I thought the comic was about how the "notify anyway" option sort of leaves you paralyzed with indecision. Because whenever it happens, you have to decide whether your text is important enough to notify them about, and how rude it would be to bypass the turned off notifications, is it worth it to keep notifying them, etc. Because White Hat is just standing there, not moving or doing anything after cueball blocks notifications, could this be an alternate explanation? (for instance, if it had just been that notifications were turned off with no bypass option, White Hat would simply be annoyed and probably keep talking anyway. But because he's given the option to bypass the filter, now he has to make a rather complicated choice and is paralyzed with indecision.)
Edit: Should I add an alternate explanation?

Talk:2555: Notifications

2021-12-20T01:50:01Z

172.69.68.200:

2556: Turing Complete

2021-12-18T21:33:44Z

172.69.68.200: /* Explanation */ what is a PDF, ForcedEntry publicized shortly before this comic

{{comic
| number = 2556
| date = December 17, 2021
| title = Turing Complete
| image = turing_complete.png
| titletext = Thanks to the ForcedEntry exploit, your company's entire tech stack can now be hosted out of a PDF you texted to someone.
}}

==Explanation==
{{incomplete|Created by a NATION-STATE THAT CAN RUN DOOM, AND CRYSIS - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

A {{w|Turing machine}} is a theoretical form of computer (as an idealised thought exercise) that has an infinite tape of symbols and can act upon and change these values as it moves up and down this tape according to specific deterministic rules.

This very simple machine can be shown to do every computational task that what we think of as a "computer" can do, given the right setup and enough time. Something that is {{w|Turing complete}} is able to act as a Turing machine, though generally with the limitation of having a finite tape, and this means it is also able to do basically every computational task.

While many pieces of hardware and software are supposed to be Turing complete (even Excel, as previously pointed out in [[2453: Excel Lambda]]), this comic implies that this was not what it was designed for. Whatever [[Ponytail]] has been referring to is not shown, but it seems to be an anecdote about how something seemingly too simple and/or specialised to exhibit such a computational equivalence has been discovered to actually be that capable.

With complex processors now installed in many household items, including large kitchen appliances like dishwashers, the possibility is raised that someone has 'hacked' such a device to do the same computational work as an actual games console. Alternatively, if hackers working on behalf of a foreign government have discovered an undetected exploit in a nation's cyber-defenses, the fact that a piece of infrastructure accessible to outsiders is Turing-complete (and could thus potentially be used to execute arbitrary code) may come as a very unpleasant surprise to the nation being attacked.

The {{w|FORCEDENTRY|ForcedEntry}} exploit is a way that was developed to allow {{w|PDF}} files to force malware onto various devices. PDF files are normally used to present documents. The exploit uses a PDF's ability to do logic operations on pixels to implement [https://googleprojectzero.blogspot.com/2021/12/a-deep-dive-into-nso-zero-click.html a simple virtual CPU] within one of the PDF renderer's decompression functions. Constructing a CPU in this way is similar to how a hardware CPU is made of individual logic gates. ForcedEntry was publicized a few days before this comic came out.

In the title-text it is suggested that this mechanism can be used for what might be more legal and practical purposes, although this might be up to some interpretation depending upon who has the right (and permission) to do what.

A {{w|Solution stack|tech stack}} is one shorthand way of describing the way an integrated grouping of communicating software packages provides everything from the deepest data handling (even as low-level as an operating system itself) to the user interface. All of these will normally be on a computer (or possibly many of them, whether locally or distributed worldwide) and if a sufficiently functional surrogate system is capable of emulating this (computing what the original computer(s) would do) then it can be considered to effectively ''be'' the same stack of technology and duplicate or replace the originals.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Ponytail and Cueball are standing next to each other]
:Ponytail:...Now, it turns out this is actually Turing-Complete...

:[Caption below the panel:]
:This phrase either means someone spent six months getting their dishwasher to play Mario or you are under attack by a nation-state.
{{comic discussion}}

[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Cueball]]
[[Category:Programming]]
[[Category:Video games]]

2555: Notifications

2021-12-16T05:29:39Z

172.69.68.200: Better transcript. Format might be off, however, the editor FAQ's worded a bit confusingly.

{{comic
| number = 2555
| date = December 15, 2021
| title = Notifications
| image = notifications.png
| titletext = It's 10:34 PM for this user. They really need to get going, they have a thing early tomorrow. Are you sure you want to notify?
}}

==Explanation==
{{incomplete|Created by an autoreplyBOT - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

[Hat Guy, Megan and Cueball are standing next to each other. Hat Guy is separated from the other two figured by a small margin.]

:Hat Guy: And another thing that annoys me about people is...
:Cueball: This user has notifications turned off.

[The camera zooms in on Megan and Cueball. Megan turns to look at Cueball.]
:Cueball: They will see your messages when they're back. '''Notify anyway?'''

[The camera zooms outward to show Hat Guy. All three figures are silently standing.]

[Megan turns to look at Cueball again.]
:Megan: What are you--
:Cueball: Shhh- It's working.

{{comic discussion}}

Talk:2549: Edge Cake

2021-12-04T02:59:01Z

172.69.68.200:

The cake being all edges is a reference to everything about her birth being an edge case.
[[Special:Contributions/172.70.110.227|172.70.110.227]] 03:41, 2 December 2021 (UTC)
: It seems likely that the title of the comic is a related pun: her birthday is an edge case, and so she has an edge cake.[[Special:Contributions/162.158.106.221|162.158.106.221]] 04:22, 2 December 2021 (UTC)
So is Hairbun officially named Emily now, sort of like how all instances of Megan are Megan even though she's only called that once? I know all the names here are just placeholders of convenience, but even then I've never know what the rules for naming are. [[User:Captain Video|Captain Video]] ([[User talk:Captain Video|talk]]) 06:11, 2 December 2021 (UTC)
: Well, Megan is referred to multiple times in the xkcds as "Megan", while the one time Hairbun was called Emily, it referred to the real{{citation needed}} Emily Dickinson. So, probably not. [[User:Bubblegum|bubblegum]]-[[User_talk:Bubblegum|talk]]|[[Special:Contributions/Bubblegum|contribs]] 02:44, 3 December 2021 (UTC)

Edge pieces on cake are often sought after because they hold more frosting, for cakes which are frosted while out of the pan. [[Special:Contributions/172.70.134.23|172.70.134.23]] 06:37, 2 December 2021 (UTC)
: I have an impression that Cueball is delighted by having only edge pieces, however some cakes edge pieces may be either sought for or avoided, depending on one's tastes. E.g. tarts have more crispy base cake content and less filling at the edges. One person may go for the filling, another for the crispy base. -- [[Special:Contributions/162.158.102.11|162.158.102.11]] 09:50, 2 December 2021 (UTC)

So it seems the events in the comic happened on Apr 1., as the "last month" birthday could be either Feb 28. or 29. -- [[Special:Contributions/162.158.102.11|162.158.102.11]] 09:50, 2 December 2021 (UTC)
:Not necessarily. Remember, Emily can have her birthday ''whenever she wants'', so the date this comic is set as is entirely arbitrary. [[Special:Contributions/172.70.178.51|172.70.178.51]] 12:26, 2 December 2021 (UTC)

Are there any particular existing arctic international flights that could have been the one Emily was born on? -- [[Special:Contributions/256.256.256.256|256.256.256.256]] 15:51, 2 December 2021 (UTC)
:There are a few possibities (at least pre-COVID, and obviously we'd be looking historically in this case anyway) as [https://interestingengineering.com/polar-routes-flights-that-go-over-earths-poles might be shown here]. There's two possible (but neither definite) International Datelines on the comic diagram, in case they help orient which from/to directions might have been diverted further in or out of their own kinks in the flightpath to coincide with 90°N. [[Special:Contributions/172.70.162.77|172.70.162.77]] 16:21, 2 December 2021 (UTC)

Expanded copies of this comic have been appearing on other comics, so large that it fills the whole screen for me. Is anyone else having this problem? [[User:Sarah the Pie(yes, the food)|Sarah the Pie(yes, the food)]] ([[User talk:Sarah the Pie(yes, the food)|talk]]) 22:24, 2 December 2021 (UTC)
:Someone (check the [[Special:RecentChanges|Recent Changes]] page, if you want) has been vandalising a lot of things. Currently I see a picture of an amphibious avian creature on this article's top (if I still need to revert it myself, I will do, but I've seen others have already been reverting other recent vandalism, so I may not need to by the time I've checked again). This very clever individual is obiviously mentally superior to us all(!) the way they can edit wiki pages seemingly at will... Impressive, eh? At some point I'm sure we'll get back to normlal, however boring that may be. [[Special:Contributions/172.70.90.67|172.70.90.67]] 23:33, 2 December 2021 (UTC)

Not to be too pedantic but isn't rotation a FREQUENCY, not a SPEED? [[User:Skulker|Skulker]] ([[User talk:Skulker|talk]]) 03:19, 3 December 2021 (UTC)
:Depends on the context (and scale). The convention is usually speed for rotation (surface(distance/time) when it's relevant, angular(revolutions/time) otherwise) to avoid conflicts with wave frequency (which is independent of speed). Also they can be freely converted, though converting to and from surface speed requires an additional radius term. The exception is, if comparing periodicity, sometimes frequency is used when it has special relevance (Ex: resonance) -- [[Special:Contributions/172.69.68.200|172.69.68.200]] 02:59, 4 December 2021 (UTC)

Tempted to add a link in the Trivia section to the [https://en.wikipedia.org/wiki/SS_Warrimoo Wikipedia] or [https://www.snopes.com/fact-check/ss-warrimoo/ Snopes] pages on the SS Warrimoo, a ship that (reportedly) was on the intersection of the Equator and the International Date Line at the stroke of midnight on January 1, 1900, with a number of interesting implications that follow. There's no way to prove that it actually happened, but it's fun to imagine and is somewhat similar to the premise of the comic. --mezimm [[Special:Contributions/108.162.221.15|108.162.221.15]] 14:33, 3 December 2021 (UTC)

Many airplanes actually have limitations written into their operating manuals that prohibit flying north of 89 deg. N or south of 89 deg. S, mostly just so that the navigation software doesn't have to deal with the singularity. [[Special:Contributions/172.69.71.187|172.69.71.187]] 23:48, 3 December 2021 (UTC)

Talk:1827: Survivorship Bias

2021-09-24T21:51:21Z

172.69.68.200:

Is "defeatest" a typo or a joke? I've never seen Randall make a typo before, but I also don't get the joke if there is one. [[Special:Contributions/162.158.2.184|162.158.2.184]] 04:28, 21 April 2017 (UTC)
:Definitely a typo. [[User:Cardboardmech|Cardboardmech]] ([[User talk:Cardboardmech|talk]]) 04:59, 21 April 2017 (UTC)
::At first I thought this was an unfamiliarity with the word, and was about to talk about how it's a real word and what it means, then I noticed the spelling, LOL! I KNOW I've seen such spelling errors several times before - often getting fixed in the next day or two - but I couldn't provide examples even if my life depended on it. And yeah, I'd say this is more "spelling error" than "typo", the I is nowhere near the E on any keyboard. :) - NiceGuy1 [[Special:Contributions/108.162.219.88|108.162.219.88]] 05:58, 21 April 2017 (UTC) I finally signed up! This comment is mine. [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 05:48, 13 June 2017 (UTC)
:::Not on the QWERTY keyboard, but on the DVORAK keyboard, the E and I are very close. and we all know how nerdy Randall is.
It has been corrected to defeatist [[User:Rtanenbaum|Rtanenbaum]] ([[User talk:Rtanenbaum|talk]]) 13:28, 21 April 2017 (UTC)
:::If itdoesn't get fixed, it might be some weird pun on "[survival of] the fittest". Wouldn't make a lot of sense in the context of the sentence though [[Special:Contributions/162.158.91.233|162.158.91.233]] 09:12, 21 April 2017 (UTC)
::::sometimes Randall do not fix errors, so nothing can be concluded on that (would it be survivorship bias to do so? ;-) How should the word be spelled (I'm not native English speaking), and does the word even exist? The spelling should be mentioned when someone explains the title text. I'm not up for it. And then if it is corrected later, it should go into the trivia section as a corrected error. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:29, 21 April 2017 (UTC)

Transcript's kind of done. [[User:Cardboardmech|Cardboardmech]] ([[User talk:Cardboardmech|talk]]) 05:17, 21 April 2017 (UTC)
:I have changed the format to the usual style and added a bit more detail. But else nicely done. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:29, 21 April 2017 (UTC)

Other than the title text, does any more work need to be done on the explanation? The Template:Incomplete param is pretty vague right now. [[User talk:AgentMuffin|~AgentMuffin]]

No doubt a lottery isn't a wise investment. However, I have not heard about accepting 25% of the prize or in annual instalments for over a decade before. Is that an american habbit? Vince [[Special:Contributions/141.101.105.174|141.101.105.174]] 06:17, 21 April 2017 (UTC)
: Never heard of such things, either... [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 08:27, 21 April 2017 (UTC)
:This is a thing that some American lotteries do. It reduces the amount that you have to pay in taxes. [[User:Mulan15262|Mulan15262]] ([[User talk:Mulan15262|talk]]) 12:49, 21 April 2017 (UTC)
: I don't play the lottery but I have heard of this practice and I think its typical here in the states. As I remember, you have the option of accepting 50% of the prize as an immediate payment or of accepting the full amount in installments over 20 years. With a progressive tax schedule this of course will affect the actual amount received and available for use. The use of payments helps the lottery itself as well and the choices of 50% and 20 years is no accident. The lottery can take the 50% it would have paid directly and invest it. A doubling period of 20 years needs an annual return on investment of only 3.6% (approx) so it works out to be a good deal for both parties. Unless of course your life expectancy is less than 20 years! [[User:ExternalMonolog|ExternalMonolog]] ([[User talk:ExternalMonolog|talk]]) 00:31, 22 April 2017 (UTC)
The title text is written in the style of an inspirational/motivational speech. Do not be deterred, you can do ANYTHING. Sebastian --[[Special:Contributions/172.68.110.58|172.68.110.58]] 07:05, 21 April 2017 (UTC)

I took the liberty of editing the very emotional text and replace it with something a bit more "professional", as I think fits this site better. I am still not quite happy about it, as advertising jackpots without taxes and not advertising the payout time are local phenomena only applicable to some jurisdictions, and make no difference to the overall survivor bias that is the theme of the comic [[Special:Contributions/172.68.182.202|172.68.182.202]] 08:16, 21 April 2017 (UTC)
: I think the whole tax stuff can be deleted. Playing lottery is always stupid - even if there were no taxes on the prize. [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 08:25, 21 April 2017 (UTC)
::I agree with Elektrizikekswerk on both issues. Lottery is just tax on low IQ we call it in my family ;-) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:25, 21 April 2017 (UTC)
::: I've heard it called "gambling for the math-impaired." [[User:Miamiclay|Miamiclay]] ([[User talk:Miamiclay|talk]]) 17:30, 21 April 2017 (UTC)

Third paragraph is taken word-by-word from Wikipedia article on Survivorship Bias. [[Special:Contributions/162.158.92.88|162.158.92.88]] 12:54, 21 April 2017 (UTC)

Here's another example of survivorship bias, "We grew up without bicycle helmets and 'nonsense' like that when kids and dogs ran free and '''we came out fine'''" but of course I also remember there were a lot of kids with concussions and there were a lot of three-legged dogs running around. Both cases have greatly decreased because of bicycle helmets and leash laws. [[User:Rtanenbaum|Rtanenbaum]] ([[User talk:Rtanenbaum|talk]]) 13:39, 21 April 2017 (UTC)
:And don't forget all the dog bites that came out "just fine"! [[User:ExternalMonolog|ExternalMonolog]] ([[User talk:ExternalMonolog|talk]]) 00:58, 22 April 2017 (UTC)

If I may suggest, survivor bias is a special example of Bastiat's "That Which Is Seen, and That Which Is Unseen", aka, the Broken Window Fallacy. The logic failure lies in paying attention to only part of the results, not all of them. I'd extend this to argue for acceptance of "The Ends Justify The Means... Buy You Gotta Consider ALL The Ends, Not Just Some Of Them". Saving 100 people is one great end. But if you also kill 10,000 of them, but in the background, where they don't stand out, the ends aren't justified.
--[[Special:Contributions/108.162.212.227|108.162.212.227]] 19:54, 21 April 2017 (UTC)

There actually was a case of a man who won the lottery after buying the same set of numbers every time. Naturally, his advice to everyone was "Keep buying the same numbers every time and you'll win eventually." Of course, there's no way he could be persuaded this was nonsense. [[User:Mark314159|Mark314159]] ([[User talk:Mark314159|talk]]) 01:43, 22 April 2017 (UTC)

This is an awfully long explanation, considering that it barely mentions Randall's assertion that *all* motivational speakers should include disclaimers (IE: "Results are not typical."). If compared by net-income versus cost-of-living, the vast majority of people end their lives with less wealth than their parents, in spite of any efforts to better their situation through education, savings, investment, et cetera. In other words, no matter how hard they try, most people lose. That's just a hard economic truth, & many people espousing hard work, dedication & especially sticking to your goals, tend to overlook the fact that financial success is actually quite rare, regardless of the lifelong effort put into it. As stated, nobody hires the failures to give talks; Maybe we should!

Also, speaking to graduating students is far from the most common activity of such professional speakers. The use of motivational speakers at conventions, paid seminars, & sales pitches is much more common & frequent than talks given to students. Since Randall doesn't mention students in any way, I think that specific phrase about students should be removed from the explanation. [[Special:Contributions/141.101.99.11|141.101.99.11]] 17:46, 22 April 2017 (UTC)

:Less wealth than their parents? While it would be hard to compare, I would argue that they mostly end up better, as technological advances makes economy grow. Although it's true that depressions can reverse it. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 00:09, 23 April 2017 (UTC)

This isn't quite relevant to the topic, but please let me vent out about a certain opinion that is going to appear in the explanation eventually: that lotteries are bad investment ''just'' because they lose you money on average. This is in fact bullshit, because so does insurance! If you really want to apply math to such things, you need to integrate welfare, not money profit, over the probabilities. Wherein welfare is some half-arbitrary function over money that denotes its actual impact on one's life and that ''usually'' grows slower than linearly on positive side (your life changes more after earning the first million dollars than after the second one), but sharply drops on the negative side (a bad debt is a life-ender). With such a welfare($) choice lottery is in fact bad while insurance is good. Note, hovewer, that in some situations, like when you already have a big debt and the mafia is killing you for it next week, lottery makes a surprisingly good, while still unlikely, investment! It's all a matter of the specific situation with welfare($). (Sorry for bad engrish, I never learned all those math terms.) [[Special:Contributions/172.68.182.136|172.68.182.136]] 20:18, 22 April 2017 (UTC)

For example, although Donald Trump had '''many''' successful businesses, he also had '''some''' that went bankrupt.
this is back to front. you need to do more research. --[[Special:Contributions/141.101.107.18|141.101.107.18]] 12:10, 24 April 2017 (UTC)

People who died in a time of war never tell us what was the price for the victory; people who didn't risk their life usually write the history though.

2520: Symbols

2021-09-24T20:47:41Z

172.69.68.200: /* Explanation */

{{comic
| number = 2520
| date = September 24, 2021
| title = Symbols
| image = symbols.png
| titletext = "röntgen" and "rem" are 20th-century physics terms that mean "no trespassing."
}}

==Explanation==
{{incomplete|Created by an internet argument - Please change this comment when editing this page. Do NOT delete this tag too soon. Bare-bones explanation is in, but needs much more detail.}}

This comic refers to notation commonly used in various fields of math and science.

d/dx and ∂/∂x are both used to represent derivatives in calculus and related fields. d/dx is most commonly used in introductory and basic calculus, while ∂/∂x is the symbol for a partial derivative, indicating a problem involving multivariable calculus, which is a level of difficulty above single-variable calculus.

ħ (pronounced 'h-bar') is a symbol used for Planck's constant, a universal constant in quantum physics equal to the energy of a photon divided by its frequency.

NA is Avogadro's number, which is used in chemistry for calculating the number of molecules in a mass of substance. Its use implies a chemistry problem where relative concentrations and orders of magnitude are important; if a mistake is made the concentration of a potentially dangerous chemical could be far too strong or too weak.

μm and mK (micrometers and millikelvin) are very small units of length and temperature respectively. Any equipment that is operating in these units will be incredibly finely calibrated and thus very expensive. Millikelvins would measure temperatures barely above absolute zero, suggesting sensitive experiments probing quantum mechanical behavior that would likely only exist in an advanced lab.

nm and eV (nanometers and electronvolts) are also small units of length and energy. Nanometres in particular are commonly used to refer to wavelengths of light, and therefore might be seen when working with lasers, which you should definitely not shine in your eye. Electron volts are a measure of energy in particle physics; particle accelerators produce intense radiation which should definitely not be directed toward your eye.

mSv (millisieverts) are a unit of radiation exposure. Randall's comment may be referring to [https://xkcd.com/radiation/ this chart].

mg/kg and μg/kg (milligrams per kilogram and micrograms per kilogram) are units used to count the proportion of a substance that contains a certain chemical; they are equivalent to 'parts per million' and 'parts per billion' respectively. These might be found when working with particularly dangerous chemicals, where even slight exposure could lead to severe health risks.

Finally, the comic references pi and tau. Pi is defined as the ratio of a circle's circumference to its diameter, while tau is defined as pi times two. Pi is more commonly used as a circle constant and is helpful when working with areas and volumes, but proponents of tau argue that it is more useful in a pure mathematics context as it makes working with radians easier. The joke here is that whichever constant you attempt to use, it will probably be the wrong one for what you are trying to achieve.

This comic discusses different symbols found in equations, and humorously comments on their implications.
*d/dx: An undergrad is working very hard
d/dx is the symbol for a single-variable {{w|Derivative|derivative}}. This is a mathematical operation that, while difficult, is well within the reach of an undergraduate student, particularly in science. Thus, an equation with this operation would be one that would cause an undergraduate student to work very hard.

*d/dx: An undergrad is working very hard
d/dx is the symbol for a single-variable {{w|Derivative|derivative}} taken with respect to x. This is a mathematical operation that, while difficult, is well within the reach of an undergraduate student, particularly in science. Thus, an equation with this operation would be one that would cause an undergraduate student to work very hard.

*∂/∂x: A grad student is working very hard
: Partial derivative. Partial differential equations are typically encountered in higher-level coursework, hence why a grad student would be working hard vs. an undergrad.
;Re
:Reynolds number, used in modelling the flow of fluids. Fluid flow cannot usually be modelled analytically and so a numerical model is necessary.
;(Ta4 - Tb4)
:Temperature component of net radiation loss. See Stefan-Boltzmann's law. This is a joke about how the Sun is a very powerful blackbody radiator.
;NA
:Avagadro's constant. If you are using this and not working in Moles there is a good chance that you will make a mistake of a factor of a power of ten. THis could create dangerous amounts of chemicals
;µm
:Micrometers are small. Any equipment that is accurate to that degree is likely to be expensive
;mK
:millikelvin are small changes in temperature, or represent very low temperatures. Equipment that uses mK is very expensive
;nm
:Describes the wavelength of laser light
;eV
:describes the energy of a particle beam
;mSv
:The amount of radiation absorbed. The pun most likely refers to internet trolls debating the effects of radiation like 5G networks, or fans of the [[2163|Chenobyl series]].
;mg/kg
:The toxicity of a chemical, per kg of body mass. If it is measured in mg/kg it is quite toxic
;µg/kg
:If the chemical is measured in µg/kg it is extremely toxic
;π or τ
:τ = 2π, so it would be easy to make a mistake and use π when τ is correct.

The title text refers to two non-SI units of radiation measurement. An area with significant amounts of radiation is probably dangerous, hence the no trespassing part.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

;d/dx
:an undergrad is working very hard
;∂/∂x
:a grad student is working very hard
;ħ
:oh wow, this is apparently a quantum thing
;Re
:someone needs to do a lot of tedious numerical work; hopefully it's not you
;(Ta4 - Tb4)
:you are at risk of skin burns
;NA
:you are probably about to make an incredibly dangerous arithmetic error
;µm
:careful, that equipment is expensive
;mK
:careful, that equipment is very expensive
;nm
:don't shine that in your eye
;eV
:definitely don't shine that in your eye
;mSv
:you are about to get into an internet argument
;mg/kg
:go wash your hands
;µg/kg
:go get in the chemical shower
;π or τ
:whatever answer you get will be wrong by a factor of exactly two

{{comic discussion}}

2520: Symbols

2021-09-24T20:46:24Z

172.69.68.200: /* Explanation */

{{comic
| number = 2520
| date = September 24, 2021
| title = Symbols
| image = symbols.png
| titletext = "röntgen" and "rem" are 20th-century physics terms that mean "no trespassing."
}}

==Explanation==
{{incomplete|Created by an internet argument - Please change this comment when editing this page. Do NOT delete this tag too soon. Bare-bones explanation is in, but needs much more detail.}}

This comic refers to notation commonly used in various fields of math and science.

d/dx and ∂/∂x are both used to represent derivatives in calculus and related fields. d/dx is most commonly used in introductory and basic calculus, while ∂/∂x is the symbol for a partial derivative, indicating a problem involving multivariable calculus, which is a level of difficulty above single-variable calculus.

ħ (pronounced 'h-bar') is a symbol used for Planck's constant, a universal constant in quantum physics equal to the energy of a photon divided by its frequency.

NA is Avogadro's number, which is used in chemistry for calculating the number of molecules in a mass of substance. Its use implies a chemistry problem where relative concentrations and orders of magnitude are important; if a mistake is made the concentration of a potentially dangerous chemical could be far too strong or too weak.

μm and mK (micrometers and millikelvin) are very small units of length and temperature respectively. Any equipment that is operating in these units will be incredibly finely calibrated and thus very expensive. Millikelvins would measure temperatures barely above absolute zero, suggesting sensitive experiments probing quantum mechanical behavior that would likely only exist in an advanced lab.

nm and eV (nanometers and electronvolts) are also small units of length and energy. Nanometres in particular are commonly used to refer to wavelengths of light, and therefore might be seen when working with lasers, which you should definitely not shine in your eye. Electron volts are a measure of energy in particle physics; particle accelerators produce intense radiation which should definitely not be directed toward your eye.

mSv (millisieverts) are a unit of radiation exposure. Randall's comment may be referring to [https://xkcd.com/radiation/ this chart].

mg/kg and μg/kg (milligrams per kilogram and micrograms per kilogram) are units used to count the proportion of a substance that contains a certain chemical; they are equivalent to 'parts per million' and 'parts per billion' respectively. These might be found when working with particularly dangerous chemicals, where even slight exposure could lead to severe health risks.

Finally, the comic references pi and tau. Pi is defined as the ratio of a circle's circumference to its diameter, while tau is defined as pi times two. Pi is more commonly used as a circle constant and is helpful when working with areas and volumes, but proponents of tau argue that it is more useful in a pure mathematics context as it makes working with radians easier. The joke here is that whichever constant you attempt to use, it will probably be the wrong one for what you are trying to achieve.

This comic discusses different symbols found in equations, and humorously comments on their implications.
*d/dx: An undergrad is working very hard
d/dx is the symbol for a single-variable {{w|Derivative|derivative}}. This is a mathematical operation that, while difficult, is well within the reach of an undergraduate student, particularly in science. Thus, an equation with this operation would be one that would cause an undergraduate student to work very hard.

*d/dx: An undergrad is working very hard
d/dx is the symbol for a single-variable {{w|Derivative|derivative}} taken with respect to x. This is a mathematical operation that, while difficult, is well within the reach of an undergraduate student, particularly in science. Thus, an equation with this operation would be one that would cause an undergraduate student to work very hard.

*∂/∂x: A grad student is working very hard
: Partial derivative. Partial differential equations are typically encountered in higher-level coursework, hence why a grad student would be working hard vs. an undergrad.
;Re
:Reynolds number, used in modelling the flow of fluids. Fluid flow cannot usually be modelled analytically and so a numerical model is necessary.
;(Ta4 - Tb4)
:Temperature component of net radiation loss. See Stefan-Boltzmann's law. This is a joke about how the Sun is a very powerful blackbody radiator.
;NA
:Avagadro's constant. If you are using this and not working in Moles there is a good chance that you will make a mistake of a factor of a power of ten. THis could create dangerous amounts of chemicals
;µm
:Micrometers are small. Any equipment that is accurate to that degree is likely to be expensive
;mK
:millikelvin are small changes in temperature, or represent very low temperatures. Equipment that uses mK is very expensive
;nm
:Describes the wavelength of laser light
;eV
:describes the energy of a particle beam
;mSv
:The amount of radiation absorbed. The pun most likely refers to internet trolls debating the effects of radiation like 5G networks.
;mg/kg
:The toxicity of a chemical, per kg of body mass. If it is measured in mg/kg it is quite toxic
;µg/kg
:If the chemical is measured in µg/kg it is extremely toxic
;π or τ
:τ = 2π, so it would be easy to make a mistake and use π when τ is correct.

The title text refers to two non-SI units of radiation measurement. An area with significant amounts of radiation is probably dangerous, hence the no trespassing part.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

;d/dx
:an undergrad is working very hard
;∂/∂x
:a grad student is working very hard
;ħ
:oh wow, this is apparently a quantum thing
;Re
:someone needs to do a lot of tedious numerical work; hopefully it's not you
;(Ta4 - Tb4)
:you are at risk of skin burns
;NA
:you are probably about to make an incredibly dangerous arithmetic error
;µm
:careful, that equipment is expensive
;mK
:careful, that equipment is very expensive
;nm
:don't shine that in your eye
;eV
:definitely don't shine that in your eye
;mSv
:you are about to get into an internet argument
;mg/kg
:go wash your hands
;µg/kg
:go get in the chemical shower
;π or τ
:whatever answer you get will be wrong by a factor of exactly two

{{comic discussion}}