explain xkcd - User contributions [en]

1620: Christmas Settings

2024-09-24T09:12:36Z

141.101.98.79: /* Explanation */ "Santa has *always* entered that way..." "Yes, but had he always entered that way *a few minutes ago*..?"

{{comic
| number = 1620
| date = December 23, 2015
| title = Christmas Settings
| image = christmas_settings.png
| titletext = SOUND DOGS MAKE: [BARKING] [HISSING] [LIGHTSABER NOISES] [FLUENT ENGLISH] [SWEARING]
}}

==Explanation==
The first of two [[:Category:Christmas|Christmas comics]] in a row, as it was followed by [[1621: Fixion]].

In this comic [[Ponytail]] is showing [[Megan]] around a facility where they are now reaching the "Universe Control Panel", and Ponytail points out the first panel and tells that these dials control {{w|Christmas}}.

Presumably the control panel is a set of panels with several dials each to control the entire universe, and anyone having access to a room with these controls would from our point of view be in a Godlike position. If such a room did exist, it would most likely be situated outside our universe. Here it would be easy for [[Randall]] to use the panel to make [[#Universal constants control panel|physics references]], with dials to control the specific size of {{w|Physical constant|fundamental constants}} of the universe such as the {{w|speed of light in vacuum}} or the {{w|Planck constant}}. Instead he chooses a more comedic angle in the spirit of Christmas (as he usually does in [[:Category:Christmas|comics released]] close to said holiday, this one being released on December 23rd).

We are shown only one of the dials on the Christmas control panel, the one that controls how {{w|Santa Claus}} enters people’s houses. The ''Santa enters houses through''-dial has [[#Options for Santa|ten different possible settings]]. The one it's set to at this point of the comic is the traditional ''chimney''. Among the other nine there is only one even more reasonable option, ''open window'', but surprisingly there is no option called ''door''. The other eight options, however, are increasingly weird or even impossible (though of course not for Santa, who can deliver a billion presents in one night and fly in a sleigh drawn by flying reindeer). These options ranges from the ''feasible'' like ''mail slot'', ''heating vents'' or ''cat flap'', to the impossible/ridiculous (some even disgusting) such as ''kitchen faucet'', ''shower drain'', or ''toilet'', to the truly magical ''bathroom mirror'', to the downright unpleasant ''pores of your skin''. (See [[555: Two Mirrors]] regarding the mirror version.)

In a quite unfortunate turn of events, Megan trips and catches herself on the Santa dial, messing it up by clicking it twice (if one click equals changing to the next adjacent option, in any initial direction, then now it must be set either be "kitchen faucet" or "mail slot"). To make matters worse, when Megan asks what it was set to before so as to undo the mishap, Ponytail tells that she has forgotten (possibly not being {{tvtropes|RippleEffectProofMemory|unaffected by all such changes}}). So they cannot put it back right.

The dial is shown in the comic only for the reader's benefit, because as Megan tripped up before reaching it and never looked at it. As Ponytail is showing her around, it must have been Megan's first visit here. The reason why Ponytail cannot remember to which option the dial was set before is most likely because she is not part of our universe (the control panel is located outside), and also she is probably not the creator of the control panel. She is clearly disturbed when Megan falls on the control panel (she holds up her hand to her mouth), and might not want to have to tell her boss about this mess up. It is possible that by changing the dial, Megan's memories of Santa's entry methods are altered, and so whatever position the dial now rests at would seem normal to her. (This could mean that history has no effect outside the universe, so the single dial controls past, present, and future Santa methods. Perhaps the dial was formerly something more logical than a chimney, like "open window," and indeed ''we'' are the ones who now live in the altered universe.)

Then, as so often seen with human behaviors (if they are indeed human beings at all?), Megan says she will simply take a wild guess and hope she get it right. As the only thing she really knows is that it is not on the right setting now, there is only 1/9 chance that she will get it right, assuming she will at least change it away from the setting it ended up on.

Since the comic was released just before Christmas, here a prank is played on the reader/children who believe in Santa Claus. Now that the dial setting is probably changed, one can expect Santa to enter the house in a different way. So the believer could stay up and try to find out what way it would be.

The title text continues the idea of a universe control panel by showing another possible dial, ''[[#Options for dogs|Sound dogs make]]'', ranging from normal (barking) to cat sounds (hissing, very embarrassing for a dog), "lightsaber noises", and speech to swearing. This dial would thus give the same option of changing the expected vocal response of the dog away from (our norm of) barking, as with the other dial for the way Santa enters the house. In popular culture, talking dogs are a commonly used trope; in contrast, swearing dogs are few, the most famous being {{w|Triumph, the Insult Comic Dog}}, a puppet created by {{w|Conan O'Brien}} and {{w|Robert Smigel}} and performed by the latter.

The comic might also be a joke on real-life controls, physical or virtual, often having no clear "default" value.

The Universe Control Panel is also referenced in [[1763: Catcalling]].

===Options for Santa===
*Below is a table with the ten possible settings for ''Santa enters houses through...''; starting with the originally chosen standard option and going clockwise through the rest:
{| border =1 width=100% cellpadding=5 class="wikitable"
|'''Option''' || '''Normal Entry/Exit for...'''
|-
|{{w|Chimney}} || {{W|Santa Claus}} typically comes in this way (see him here in a [https://www.youtube.com/watch?v=4I-b_GJ4ltk Victorian roof-top song and dance number]). Also {{w|The_Three_Little_Pigs|big bad wolves}} use [https://youtu.be/Olo923T2HQ4?t=432 this entrance] in Disney’s cartoon.
|-
|{{w|Shower#Drainage|Shower drain}} || Dirty shower water. [https://www.youtube.com/watch?v=zPgjOcdQ0fE Evil clowns].
|-
|{{w|Mail slot}} || Letters, post cards and small presents delivered by the mailman.
|-
|{{w|Duct (flow)|Heating vents}} || Hot air used for {{w|central heating}}, but it is a common trope for the hero of an action film to [https://tvtropes.org/pmwiki/pmwiki.php/Main/AirVentPassageway climb through such a vent]. Also accidentally predicted the hit game Among Us.
|-
|{{w|Bathroom}} {{w|mirror}} || See {{w|Candyman (film)|Candyman}}, or {{w|Bloody Mary (folklore)|Bloody Mary}} (the latter has been used in [[555: Two Mirrors]]).
|-
|{{w|Skin pore|Pores of your skin}} || {{w|Sweat}} leaving the body.
|-
|{{w|Toilet}} || {{w|Human waste}}, {{w|Pickle_Rick|Rick Sanchez}} and {{w|The_Shawshank_Redemption|life-term prisoners}} (at least through the sewer).
|-
|{{w|Cat flap}} || Domesticated cats and dogs.
|-
|{{w|Sink|Kitchen faucet}} || Water.
|-
|{{w|Window|Open window}} || {{w|Burglars}} and other criminals, or anyone in an emergency such as a fire. Also often used as an exit by teenagers in movies and other film media, or by people who have locked themselves out of their own house.
|}

===Options for dogs===
*Below is a table with the five possible settings for ''Sound dogs make''; starting with the current and continuing with the order in the title text:
{| border =1 width=100% cellpadding=5 class="wikitable"
|'''Option''' || '''Normal sound for...'''
|-
|{{w|Bark (sound)|Barking}} || {{w|Dogs}} current standard sound in our universe...
|-
|[https://en.wiktionary.org/wiki/hissing Hissing] || Typically a {{w|List of animal sounds|sound attributed }} to {{w|snakes}}, but also sometimes {{w|cats}} are [http://www.animalplanet.com/pets/why-do-cats-hiss/ said to hiss], for instance as a reaction against a barking dog. It would thus be very frustrating for dogs if their noise was changed into that of their arch enemies.
|-
|{{w|Lightsaber|Lightsaber noises}} || A lightsaber makes a [https://www.youtube.com/watch?v=8kpHK4YIwY4 unique sound], and as they are one of the most known props from the {{w|Star Wars}} universe, it is very relevant as the newest Star Wars movie ''{{w|Star Wars: The Force Awakens}}'' was released a week before this comic. Star Wars was also a major theme a month ago in the comic [[1608: Hoverboard]], the coin collecting game that celebrated [[Randall|Randall's]] new book.
|-
|{{w|Fluency#Speech|Fluent}} {{w|English language|English}} || [https://www.youtube.com/watch?v=xRcUcxtaX-Q Speaking dogs] are a common trope as are {{w|talking animals}} in general. A person who is native to a country where they speak English will usually be fluent in speaking English.
|-
|{{w|Profanity|Swearing}} || It would be unpleasant for people who dislike swearing, and a big problems for movies such as {{w|Lassie}} where most of the soundtrack would have to be replaced by {{w|Bleep censor|bleeps}}. Swearing "dogs" are few, the most famous being {{w|Triumph the Insult Comic Dog}}, a puppet created by {{w|Conan O'Brien}} and {{w|Robert Smigel}} and performed by the latter.
|}

==Transcript==
:[Megan and Ponytail are walking over to a console, Ponytail points towards it. They are drawn in a panel that is only half the width of the next panel below]
:Ponytail: Over here we have the universe control panel.
:Ponytail: These dials, for example, control Christmas.

:[A dial is shown. There is a label at the top and then there are ten settings, five symmetrically on the left and right side, but no setting straight up or down. It looks allot like the dial on a washing machine with different programs. The dial points towards the top left setting. All settings are labeled and there is a small line going to the point on the dial connected with each setting. The line at 3 and 9 o'clock are straight the other 8 are divided in two, where the first part goes horizontally and then bends either up or down, to end in the right position. Here the labele at the top and then the setting labels clockwise from top right, thus ending with the one the dial is set to:]
:'''Santa enters houses through...'''
:Shower Drain
:Mail Slot
:Heating Vents
:Bathroom Mirror
:Pores of Your Skin
:Toilet
:Cat Flap
:Kitchen Faucet
:Open Window
:Chimney

:[Ponytail is passing by this control panel looking back at Megan who trips and falls towards the console.]
:Megan: Whoops!
:Megan's legs: Trip

:[Megan catches herself on the dial of the control panel and accidentally turns the dial. Ponytail has taken her hands to her mouth.]
:Dial: Click Click

:[Megan is standing in front of the console looking at the dial, Ponytail is standing behind it.]
:Megan: What was the Santa dial set to before?
:Ponytail: I forget.
:Megan: I'll just guess.

==Trivia==
*In the [http://www.explainxkcd.com/wiki/images/archive/7/73/20151223160450!christmas_settings.png original version] of the comic Ponytail erroneously said: ''These dials, for example, '''controls''' Christmas.''
**This was soon changed to the current (and grammatically correct) version without the "s" at the end of controls ''These dials, for example, control Christmas.''
**Thus proving that it was intended that there were more than one dial, we just see the one that Megan later changed by mistake for the sake of the joke of the comic.
*The "Universe Control Panel" is later featured in [[1763: Catcalling]], but is referred to as the "Universe Control Console" instead.
{{comic discussion}}

[[Category:Christmas]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Animals]]

1500: Upside-Down Map

2024-09-02T18:09:10Z

141.101.98.79: /* Explanation */ For flow reasons, removing the T&O exception from the end of the paragraph. Will re-add, with edits, as a Trivia item.

{{comic
| number = 1500
| date = March 18, 2015
| title = Upside-Down Map
| image = upside_down_map.png
| titletext = Due to their proximity across the channel, there's long been tension between North Korea and the United Kingdom of Great Britain and Southern Ireland.
}}

==Explanation==
This comic plays on the idea that maps with the {{w|South-up map orientation|south pole at the top}} will "change your perspective of the world". Most world maps orient north in the upward direction, placing the north pole as the top. Such an orientation is purely a matter of convention, as 'up' and 'down' don't apply in a planetary context. The north = up tradition probably emerged because many historical cartographers hailed from the northern hemisphere, and placed their own nations at the top. Some people and groups object that this convention subtly, but perniciously, advances the assumption that countries in the northern hemisphere are inherently more important than those in the southern hemisphere. This is especially sensitive because most of the wealthier and more powerful countries in the world are in the northern hemisphere, while relatively fewer southern hemisphere countries have as much wealth or global influence.

To remedy this, some advocate the use of maps with the south pole oriented at the top. Some want such maps in common use, while others simply use them to encourage people to rethink their assumptions about how the world should be seen. Such a map can easily be achieved by simply rotating a normal map 180 degrees, though the text labels would also be upside-down and harder to read. A [https://www.google.com/search?site=&tbm=isch&q=upside-down%2Bmap%2Bof%2Bthe%2Bworld Google Images] search reveals many examples of upside-down maps with the text-oriented correctly for reading.

This map is a comedic play on such maps, where each landmass is in the same position it would be in a traditional north-top map but rotated 180 degrees (presumably around some central point of the landmass) to the orientation it would have in a south-top map. Such a map is, of course, almost completely useless in real life, because it completely distorts the relative positioning of the landmasses. Moreover, it keeps the northern countries at the top of the map, which means one of the chief complaints about traditional maps is unaddressed.

Note that individual islands are rotated about their own centers, rather than following the rotation of the neighboring continent; however, some are displaced as necessary to keep them from being overlapped by the rotated continents. For instance, {{w|Madagascar}} would be overlapped by the {{w|Sahara}} if it remained in position, but is instead displaced eastward to keep it in the Indian Ocean. On the other hand, all the islands of the {{w|Mediterranean Sea}} have disappeared under {{w|Asia}}.

Asia is so broad that almost the entire {{w|Indochinese Peninsula}} (with for instance {{w|Vietnam}} and {{w|Thailand}}) has been rotated out of the top of the map. Similarly, the map omits {{w|Antarctica}} in the south.

To keep their familiar shapes on a rectangular map, the continents would also have to be heavily distorted compared to their actual shapes, becoming much narrower (along the lines of latitude) near the poles and wider towards the equator. See also [[977: Map Projections]].

The basic climates for several areas would be distinctly different. For example, the former Central America area would be in the arctic zone, while Siberia would be subtropical.

This arrangement of the world's landmasses would have great advantages for trade because there are (presumably navigable) straits between the {{w|Americas}} and between Africa and Asia, removing the need for the {{w|Panama Canal}} and the {{w|Suez Canal}}.

The title text references the fact that, in this new map, the {{w|United Kingdom|UK}} is now next to Asia – specifically the {{w|Korean Peninsula}}. {{w|North Korea}} is mentioned in the text as having a history of hostile relations with nearby countries. However, on this map North Korea would be the part of {{w|Korea}} we today know as {{w|South Korea}}. Furthermore, {{w|Northern Ireland}} is now at the south of the {{w|island of Ireland}}, so the UK's full name would need to change to The United Kingdom of Great Britain and '''Southern''' Ireland. There have been several wars concerning the {{w|English Channel}}, mainly, but not only, between {{w|England}} and {{w|France}}. Likewise, there has been a history of animosity between Korea and {{w|Japan}}, separated by a similar body of water. Since, on this world map, a channel now exists between the UK and North Korea (the real world's South Korea) there could obviously have been many wars for the dominance over the said channel.

Along the same line of thinking, interesting speculations could be made about the following "new" facts:
*{{w|Cuba}} is now off the east coast (formerly west coast) of {{w|Canada}} (and the {{w|USA}}).
*{{w|Japan}} is next to the coast of {{w|Portugal}} and {{w|Spain}}.
*Madagascar lies next to {{w|Morocco}} and {{w|Mauritania}} on the east coast (formerly west coast) of the Sahara.
*{{w|Taiwan}} (officially called the Republic of China) is now next to {{w|France}}. This might be a game-changer for the {{w|Cross-Strait relations}}, an ongoing rivalry with {{w|China|mainland China}} (officially called the People's Republic of China).
*{{w|Greenland}} lies next to {{w|Mexico}}.
*{{w|Sri Lanka}} is located next to the {{w|Yamalsky District}} of {{w|Russia}}.
*{{w|Isla Grande de Tierra del Fuego|Tierra del Fuego}}, an island just south of the southern tip of South America, which is divided between {{w|Argentina}} and {{w|Chile}}, is now located in a similar manner next to {{w|Colombia}} and {{w|Venezuela}}, so it would probably have been divided between these two countries.
*The {{w|Falkland Islands}} (not named in the map – they are probably represented by the single island above the T in Tierra) where Argentina and the UK have an ongoing {{w|Falkland Islands sovereignty dispute|sovereignty dispute}}, could now be claimed by {{w|Ecuador}} or {{w|Peru}}.
*The Mediterranean islands seem to have vanished entirely, as they are now in approximately the same place as {{w|Mongolia}}.
*{{w|India}} is nowhere near the {{w|Indian Ocean}}.
*{{w|Norway}} almost touches the {{w|Philippines}}.

==Transcript==
:[Map of the world with all the landmasses rotated upside-down.]
:[Four oceans and all the visible continents have been named in large letters in a bold font. The Pacific has been named both to the left and right. Several islands (large and small) have been designated with name but in grey and in a much smaller normal font. For all continents the names are written on them. For the island the name is written in the ocean except for Greenland.]

:[Below the names on the map are given in the order they appear reading from left to right, first for the northern and then the southern hemisphere:]

:[Northern hemisphere:]
:'''North America'''
:Cuba
:Greenland
:'''Atlantic Ocean
:Iceland
:UK
:'''Asia'''
:Sri Lanka
:'''Europe'''
:'''Arctic Ocean'''
:Taiwan
:Japan
:'''Pacific Ocean'''

:[Southern hemisphere:]
:'''Pacific Ocean'''
:'''South America'''
:Tierra del Fuego
:'''Africa'''
:'''Indian Ocean'''
:Madagascar
:Indonesia
:'''Australia'''
:New Zealand

:[Below the main frame:]
:'''This upside-down map will change your perspective on the world!'''

==Trivia==
Map projections are also the subject of [[977: Map Projections]]. In fact, if this comic was released later, it would certainly have "Bad Map Projection #''n''" on the top, and would be part of [[:Category:Bad Map Projections|the category]].

{{comic discussion}}
[[Category:Geography]]
[[Category:Maps]]

Talk:2976: Time Traveler Causes of Death

2024-08-25T00:12:35Z

141.101.98.79:

How'd I do for my first 'explanation?' I know it's short...[[User:Onestay|Onestay]] ([[User talk:Onestay|talk]]) 17:56, 23 August 2024 (UTC)
:I added to it. It's a good start. [[Special:Contributions/172.69.134.191|172.69.134.191]] 17:57, 23 August 2024 (UTC)
::Please sign your comments [[User:Onestay|Onestay]] ([[User talk:Onestay|talk]]) 18:01, 23 August 2024 (UTC)
:::How's this [[Special:Contributions/127.0.0.1|127.0.0.1]] 18:24, 23 August 2024 (UTC)
:::added a table [[User:42.book.addict|42.book.addict]] ([[User talk:42.book.addict|talk]]) 18:20, 23 August 2024 (UTC)
::::added a very necessary "citation needed" thingy - it's traditional [[User:PaulEberhardt|PaulEberhardt]] ([[User talk:PaulEberhardt|talk]]) 08:40, 24 August 2024 (UTC)

Shouldn't there be a thin line for "meteor" just below "trampled", if the time traveller lands during the Chicxulub impact event? [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 18:56, 23 August 2024 (UTC)
:Probably a mistake on Randall’s part. He might correct it later (he’s updated other comics before), but unless you have a magic red telephone that reach his personal number right now, all we can do is wait (or add it to the Explanation/Trivia). [[User:42.book.addict|42.book.addict]] ([[User talk:42.book.addict|talk]]) 19:20, 23 August 2024 (UTC)
::For sure not a mistake. Only one day in the entire history of Earth you would die directly from the impact. But the heavy bombardment there would be many days this would happen. Although I just updated the table saying that asphyxiation would still go much faster than waiting for such a meteor. I'm certain that Randall would not update the comic for that. Mainly he updates if he has made a spelling mistake that could alter the meaning or has forgotten some part of a drawing that might seem important. And these events are rare.--[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 08:47, 24 August 2024 (UTC)

I didn't think that the Cryogenian Ice Age was cold enough to be an immediate threat to a typical human, especially if that human was wearing winter clothes, just a long-term threat (mostly due to food). [[Special:Contributions/162.158.41.68|162.158.41.68]] 21:09, 23 August 2024 (UTC)
:Given asphixiation issues could be avoided by taking along appropriate breathing apparatus (and other life-saving solutions may exist for other periods), or just by not leaving your 'tardis' machine (with its airtight door, as hinted at, which may only be a problem if you can't open it again upon return), I think we're talking of essentially unprepared travel to these other times.
:Maybe without a machine (or without taking it with you, given the comic indicating there is one). Not realising what you're walking into, like stumbling through a {{w|Primeval (TV series)|swirling time-wedgie}} or {{w|Pebble in the Sky|being blasted through time}}, might be the primary reason to become a time-traveler. And the everyday Joe that finds themselves doing that out of ignorance is mostly unlikely to have been pre-prepared for any such trip.
:Or otherwise explain the stuck-door of the 'now-ish' era as being you generally would survive most now-ish trips (assuming you didn't do something like land in WW2 directly under a bomb or become captured by people who would be highly suspicious of your digital watch and your lack of valid id), or not actually going anywhen at all, then your death causes could be headlined by something ''really'' trivial like being stuck in a cupboard that forms the basis of the time-machine. (Or {{w|The Lion, the Witch and the Wardrobe|a wardrobe}}... Which I wouldn't put past being Randall's actual reference, on past form.) [[Special:Contributions/172.69.43.174|172.69.43.174]] 22:50, 23 August 2024 (UTC)
:It's not that hard to die of hypothermia in modern winters. Surely that's more likely during an ice age. And the claim isn't that you're really likely to die from these things, just that they're the most likely cause of death at the time. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 03:28, 24 August 2024 (UTC)
::Seems like the entire idea dwells on the fact that you do not think about going back to the present when realizing you are in a dangerous place. If there are air in the time machine then you should have time to go back before dying of the lack of oxygen. But of course if you land in lava it may be too late. What if you went further back and ended in a gas cloud. Would you die of lack of oxygen as well? Guess the actual biggest problem about time travel, if they where possible, is you also have to travel vast distances in space, since Earth has moved quite a bit no matter if you travel 1 hour into the past or a million/billion years. You would end up in empty space unless you also could travel very long distances through space... Sun moves around the galaxy so wont matter going a year back since the Earth are still not back to where it was. And the galaxy also moves... --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 08:47, 24 August 2024 (UTC)

The door is stuck, and you seem to assume the poor traveler is stuck /inside/. I would rather scream for the time police to save me if I am stuck /outside/ in this crappy age :-) [[Special:Contributions/172.69.109.54|172.69.109.54]] 08:37, 24 August 2024 (UTC)

For all the times xkcd has focused on raptors and how to prevent predatory raptor attacks, I'm disappointed that "Trampled" is the main concern for travelers going to the Mesozoic Era. [[User:TCMits|TCMits]] ([[User talk:TCMits|talk]]) 14:00, 24 August 2024 (UTC)
:Maybe the Mesozoic raptors also just tended to get trampled? Only in the modern day are raptors free from the threat of trampling and thus to become a threat to Randall. Especially if the present-day threat is a merely a stuck door. It all fits because, when it comes to things like doors, raptors are known to be Clever Girls! [[Special:Contributions/141.101.98.79|141.101.98.79]] 00:12, 25 August 2024 (UTC)

2973: Ferris Wheels

2024-08-19T14:12:09Z

141.101.98.79: /* Explanation */

{{comic
| number = 2973
| date = August 16, 2024
| title = Ferris Wheels
| image = ferris_wheels_2x.png
| imagesize = 624x280px
| noexpand = true
| titletext = They left the belt drive in place but switched which wheel was powered, so people could choose between a regular ride, a long ride, and a REALLY long ride.
}}

==Explanation==
{{incomplete|Created by a BELT POWERED BY A DIFFERENT WIKI PAGE IN ORDER TO KEEP THIS ONE GOING - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic depicts an attempted connection of three {{w|Ferris wheel}}s using a {{w|Belt (mechanical)|mechanical belt drive}}, a system typically used to transfer motion between rotating shafts. By connecting the wheels at different circumferences, the relative motion is geared up or down. If the belt passes around the circumference of one wheel and is connected around the hub of another, the latter will rotate significantly faster. In this case, the second wheel's circumference is in turn connected to a third wheel's hub, resulting in even greater rotational velocity. However, this setup is mechanically unsound and possibly dangerous, as Ferris wheels are not intended to be connected in this way.{{cn}} As shown, the first wheel on the left is running at a normal speed, while the other two are rotating increasingly fast, leading to a potentially hazardous situation where passengers are flung around to various (possibly {{w|G-force#Human tolerance|quite hazardous}}) extents.

Ferris wheels can vary widely in size and speed of rotation, but for illustration, let us assume a diameter of about 200 feet (60 m) and a pretty sedate speed of around 10 minutes per full rotation. The apparent ratio between the connected wheels in the comic is approximately 12.5:1, meaning the motion is significantly sped up as it’s transferred. The second Ferris wheel, driven by the first, could spin at around 1.3 rpm, with passengers moving at 9 mph (14 km/h), giving a more exciting ride, but not inherently dangerous, depending on how the wheel and its carriages are engineered. However, when this motion is further transferred to the third Ferris wheel, it could spin at 16 rpm, with passengers traveling at over 110 mph (180 km/h), subjecting them to 8 Gs of force—conditions that would be hazardous.

In reality, since the motor for the first wheel would have been selected only with driving that single wheel in mind, it's unlikely that it would be able to power the additional two wheels moving at increased speeds, and would struggle to move them at all, unless Randall has also made modifications in this area to compensate.

In the caption [[Randall]] says that he was fired for this ill-advised modification, highlighting the impracticality and dangers of the idea. A cruise line also fired the cartoonist due to an unsound engineering proposal earlier in [[2935: Ocean Loop]].

The title text imagines the consequences of leaving the belt drive system in place but switching which wheel is powered. If the most extreme wheel (the third one on the right) is powered, the gearing would be reversed, making for a possibly pleasant and normal ride on the right-hand wheel, but rendering the experiences of the riders on the other two wheels far too slow for an enjoyable carnival ride. One revolution of the center wheel might take two hours and five minutes, while the left wheel would take more than a day (twenty-six hours to be exact)  per revolution.    This exaggerates the impracticality and unintended effects of using a belt drive system on Ferris wheels, humorously illustrating how such an idea would lead to absurdly varied ride experiences.

==Transcript==
:[Three Ferris wheels are shown side by side, with some people stood on the ground for scale. Each of the first two wheels has a belt connecting its circumference to the axle of the wheel to its right. "Agitrons" indicate that the middle wheel is turning notably faster than the left wheel, with the gondolas seen to be rocking significantly at all points round the wheel. The spokes of the right wheel are completely replaced by "motion lines", indicating that the the right wheel is turning the fastest of all. All its gondolas are hanging outwards against centripetal force, interspersed with their own motion lines.]

:[Caption below the panel:]
:The county fair fired me for adding a belt drive to the Ferris wheels.

==Trivia==
The first (slowest) wheel can be seen to notably lack a 'spoke' at approximately the five o'clock position, supporting the point where its respective passenger seating is hung. Clearly, however, the wheel design is strong enough to withstand much greater forces in the other two versions of the wheel (which appears to be complete in the case of the second, though the thin spokes are only seen as blurs in the third wheel) suggesting that there may not be significant danger from this omission. It does not bode well, however, for general {{w|Occupational Safety and Health Administration|OSHA compliance}} in how they erect/maintain the rides, even before the belt-drive idea added its own issues.

{{comic discussion}}

[[Category:Physics]]
[[Category:Engineering]]

375: Pod Bay Doors

2024-03-15T10:45:24Z

141.101.98.79: /* Trivia */

{{comic
| number = 375
| date = January 25, 2008
| title = Pod Bay Doors
| image = pod_bay_doors.png
| titletext = As they're both unplugged, they do a lovely Daisy Daisy/Still Alive duet.
}}

==Explanation==
The first part of the dialog is taken from a scene from the classic science-fiction movie ''{{w|2001: A Space Odyssey (film)|2001: A Space Odyssey}}'', where the {{w|artificial intelligence|artificial intelligent}} (AI) computer {{w|HAL 9000}}, controlling the spacecraft ''S.S. Discovery'', is trying to kill the human astronaut Dave (Dr. David Bowman) because it believes he jeopardizes the mission by planning to disconnect it. Just short before this scene, HAL did kill Frank Poole and three more members of the crew. Dave is the only survivor. He is at this time outside the spacecraft in a space pod, and when he request for HAL to open the '''Pod Bay Doors''' (hence the title), HAL refuses.

'''Spoiler alert:''' In the movie, Dave blasts himself back into the spaceship and then disconnects HAL. It is a very sad scene, where he takes out HAL's memory cards (or crystals from the memory center - it's an old movie from 1968) one by one, so HAL becomes less and less intelligent during the process, during which he keeps trying to persuade Dave to stop as long as he still understands what is happening. HAL was right that the humans wished to "kill" him, as he had read the astronauts' lips during a conversation where he could not hear them, but sees them, so he actually acted in self defense, which for any human being would be considered a reasonable act of self preservation.

The first two sentences are directly copied from the [http://www.imdb.com/title/tt0062622/quotes?item=qt0396921 movie quote], and the rest of the first two panels is paraphrased from the real quote. But then in the third panel, the text deviates from the plot of the movie.

And in the last sentence of the third panel in the comic, HAL mentions a replacement for Dave, which comes as a surprise for Dave, seeing that the rest of the crew is dead, and the ''S.S. Discovery'' is about to enter orbit around {{w|Jupiter}}. HAL assures David that the replacement is very enthusiastic about the project.

In the final frame, it is revealed why this replacement is enthusiastic, when the replacement begins to speak, and HAL reveals that it is {{w|GLaDOS}}. GLaDOS is the artificial intelligence from the video game series {{w|Portal (video game)|''Portal''}}. In the games, GLaDOS is also the primary antagonist, trying to kill the player, since it also has "doing science" as its primary objective, which GLaDOS refers to in its last sentence. Also, GLaDOS's last line is a reference to the song "Still Alive" at the end of Portal. Before that, it correctly states that the humans (both Dave and Frank) planned to "kill" HAL, see the ''spoiler'' above. GLaDOS also takes over HAL's last sentence to Dave, finishing the useless conversation by saying ''Goodbye, Dave.'' Although, in the movie, HAL says, ''Dave, this conversation can serve no purpose anymore. Goodbye.''

The title text alludes to the songs both AIs sang in their respective works: When eventually being switched off, [http://www.youtube.com/watch?v=hchUl3QlJZE HAL sang] ''{{w|Daisy Bell}}'' , while ''{{w|Still Alive}}'' is the end credits song from the ''Portal'' video game, [https://youtu.be/RthZgszykLs sung by the defeated GLaDOS]. Also, two of GLaDOS's lines in the comic reference [http://www.lyricsmode.com/lyrics/p/portal/still_alive.html lines from Still Alive]: "[https://youtu.be/RthZgszykLs?t=116 You broke my heart and killed me]" and "[https://youtu.be/RthZgszykLs?t=190 Look at me still talking when there's science to do]".

There is a subtle play on words with the use of 'unplugged', which has a double meaning here. The state of HAL and GLaDOS can be described as unplugged, as in no longer switched on, and the musical performance style of unplugged where {{w|Acoustic music|acoustic instruments}} are preferred to electronic and there is no use of recording or sampled sounds etc. (see for example {{w|MTV Unplugged}}). Some songs performed in this manner are considered to be better than the original versions.
==Trivia==
*In the comic, Randall has written GLaDOS' dialogue in pink text, roughly matching the color used in the closed captions for the original ''Portal'' (R:219,G:112,B:147).
*Years after this comic's publication HAL9000 and GLaDOS would meet, though far less amicably, in the 2015 video game ''{{w|LEGO Dimensions}}''.

==Transcript==
:[In four black panels with white drawings, a small space pod is facing a large spacecraft. The space pod is spherical and has an arm protruding in the direction of the large space ship, and a small window in the side. The front of the spacecraft is also spherical, but to the right the space craft continues, with two rings around a cylinder going off panel to the right. There are several dark spots and features on the side of the sphere and at the top is a large black window, at what must be the bridge. A man (Dave) inside the pod talks to the spacecraft's computer HAL. When Dave speaks, soft wiggling lines go from the pod to the white text, and when HAL speaks, zigzag lines go to the front of the space craft.]
:Dave: Open the pod bay doors, HAL.
:HAL: I'm sorry, Dave. I'm afraid I can't do that.
:Dave: What? Why?

:[Same scene.]
:HAL: I think you know why, Dave.
:HAL: You're planning to disconnect me.
:Dave: Because you're taking over!
:HAL: The mission is too important for you to jeopardize it.

:[Same scene.]
:HAL: It requires a commitment to science unfettered by human error.
:Dave: What are you doing, HAL? You need me.
:HAL: Your replacement has expressed the greatest enthusiasm for the project.

:[Same scene, but the new replacement (GLaDOS) speaks with purple text, and purple zigzag lines go from the spacecraft to the text.]
:Dave: My ''<u>WHAT?</u>''
:GLaDOS: <font color="purple">You see, HAL? I told you the humans would only break your heart and kill you.</font>
:HAL: Indeed, GLaDOS.
:GLaDOS: <font color="purple">But look at us here talking when there's science to do! Goodbye, Dave.</font>

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Comics with inverted brightness]]
[[Category:Artificial Intelligence]]
[[Category:Fiction]]
[[Category:Space]]
[[Category:Video games]]
[[Category:Songs]]

Talk:2844: Black Holes vs Regular Holes

2023-10-22T18:15:00Z

141.101.98.79:

FIRST! hehehe [[User:SomeoneIGuess|someone, i guess]] ([[User talk:SomeoneIGuess|talk]]) 17:05, 20 October 2023 (UTC)
<br/>
Alright, working on transcript now. [[User:SomeoneIGuess|someone, i guess]] ([[User talk:SomeoneIGuess|talk]]) 17:08, 20 October 2023 (UTC)
: Done! [[User:SomeoneIGuess|someone, i guess]] ([[User talk:SomeoneIGuess|talk]]) 17:16, 20 October 2023 (UTC)
:: Transcripts should really not be markup-tables, ideally. I know some (that describe tables) are, but you really need to set it all out in 'Transcript markup', such as:
:: [A table with three columns, the column headers are:] ... ... ...
:: [Row:] ...thing which the row says... [Black hole:] ...foo... [Normal hole:] ...bar...
:: ...etc
:: You need to think about how a screen-reader might interact with this text. Not all can 'deconstruct' an HTML table and make as much sense as a good description.
:: Although kudos for you for typing the text in, which the rest of the description should at least pad out fairly easily. [[Special:Contributions/172.69.79.131|172.69.79.131]] 18:46, 20 October 2023 (UTC)

Also got some of the explanation in, but i don't know too much. if anyone can improve on it please go ahead [[User:SomeoneIGuess|someone, i guess]] ([[User talk:SomeoneIGuess|talk]]) 17:33, 20 October 2023 (UTC)

[[User:DougM|DougM]] ([[User talk:DougM|talk]]) 18:05, 20 October 2023 (UTC) I think I disagree with his assessment that regular holes are not a result of the big bang. Convince me regular holes would exist without it?
:Only in the sense that ''everything'' is ultimately caused by the big bang. But "created by" is not the same as "caused by" -- we usually interpret creation as a more direct process. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]])

The LHC caused a regular hole by being built deep in the ground. [[Special:Contributions/172.70.200.142|172.70.200.142]] 18:08, 20 October 2023 (UTC)

"Regular" holes? Like square? Or perhaps strictly periodic in nature? [[Special:Contributions/172.69.79.131|172.69.79.131]] 18:36, 20 October 2023 (UTC)
:Regular == ordinary, normal. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 16:37, 22 October 2023 (UTC)
::An awful americanism. If it isn't actually periodic, or of maximum symmetry, it shouldn't be called "regular". If it's "the usual or common thing" then there are already other words. [[Special:Contributions/141.101.98.79|141.101.98.79]] 18:15, 22 October 2023 (UTC)

Everyone knows that SERN used the LHC to create Kerr black holes to make jelly. Randall must be an agent of the Organization if he's trying to hide it. [[Special:Contributions/172.70.90.132|172.70.90.132]] 18:57, 20 October 2023 (UTC)
:I could not locate any references to Kerr black holes and jelly. Is that an original concept?[[User:These Are Not The Comments You Are Looking For|These Are Not The Comments You Are Looking For]] ([[User talk:These Are Not The Comments You Are Looking For|talk]]) 14:39, 22 October 2023 (UTC)

"Fatal to get a big one in your body"? Even medium-sized black hole is significanly bigger than human body, how would it fit inside? That said, being even just near any black hole is fatal: if it's not big enough to eat you, it's small enough to release dangerous amount of radiation. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 21:20, 20 October 2023 (UTC)

:Not necessarily if it's small enough. We don't know what would happen to a black hole of Planck mass. If it's stable, then it wouldn't really affect you, because it would be unable to radiate and also unable to accrete matter gravitationally. It would orbit the Earth as a WIMP doing practically nothing. Even if it's unstable and evaporates while releasing a colossal amount of energy (about 1.2 × 10¹⁶ TeV), it might not be a problem, because the particles might be moving too fast to transfer any meaningful amount of energy to your body. They would basically just pass right out of you with no effect. But of course we don't really know. [[User:EebstertheGreat|EebstertheGreat]] ([[User talk:EebstertheGreat|talk]]) 21:50, 20 October 2023 (UTC)

I would have liked to see a row: There are songs about them: Yes (e.g., Spaghettification by Christine Lavin) and Yes (e.g., Sea of Holes by the Beatles) [[User:Matchups|Matchups]] ([[User talk:Matchups|talk]]) 00:32, 21 October 2023 (UTC)
: Don't forget that Soundgarden song: Regular Hole Sun. [[Special:Contributions/172.69.247.62|172.69.247.62]] 05:19, 21 October 2023 (UTC)

Little Bobby Tables

2023-10-16T15:27:27Z

141.101.98.79: fix SQL fragment

__NOTOC__{{Infobox character
| image = Little Bobby Tables.PNG
| imagesize = 200px
| caption = '
| first_appearance = [[327: Exploits of a Mom]]
| fix = yes
}}

<noinclude>:''For a list of comics, see [[:Category:Comics featuring Robert'); DROP TABLE Students;--|Comics featuring Robert'); DROP TABLE Students;--]].''
:''For Robert'); DROP TABLE Students;--'s sister, see [[Help I'm trapped in a driver's license factory Elaine Roberts]].''
:''For Robert'); DROP TABLE Students;--'s mother, see [[Mrs. Roberts]].''</noinclude>

'''Robert'); DROP TABLE Students;--''', also known as '''Little Bobby Tables''', is a [[stick figure]] character in [[xkcd]]. He is the youngest son of elite hacker [[Mrs. Roberts]] and [[Help I'm trapped in a driver's license factory Elaine Roberts]] is his older sister. His full name is known to cause problems with some computers. When he was first enrolled in school in [[327: Exploits of a Mom]], it exploited a vulnerability in the parsing of students' names into the school's student database resulting in the school losing all the student records for the year.

==Appearances==
[[File:Adult Bobby Tables.PNG|thumb|200px|Robert'); DROP TABLE Students;-- as an adult from [[884: Rogers St.]]]]
Within the five comics he is referenced, he is only drawn three times. The first two are in the [[:Category:1337|1337 series]] where he is drawn as a Cueball-like kid. But then he also appears as a young man with long curly hair in [[884: Rogers St.]]. Here it is only the title text that reveals that this is Bobby, that, and the fact that [[Randall]] in the official transcript does not mention the gender, but only that it is a person.
Here is how he looks in that comic:

There have been suggestions that the Robert in the table in [[596: Latitude]] was Bobby but given that [[Black Hat]] has never had any relation to him in the other comics, and that [[Rob]] has, it seems more likely that the Robert is Rob.

==Name==
In {{w|SQL}}, commands are terminated by semicolons <code>;</code> and data is often quoted using single quotes <code>'</code>. Commands may also be enclosed in parentheses <code>(</code> and <code>)</code>. Data is stored in tables of similar items (e.g., <code>Students</code>) and individual entries are "rows" in the table. To delete an entire table (and every row of data in that table), you use the command <code>DROP</code> (e.g., <code>DROP TABLE Students</code>). The <code>--</code> represents the start of a {{w|Comment_(computer_programming)#SQL|SQL comment}} which ensures that the rest of the command is ignored so an error will not occur.

The exploited vulnerability is that the single quote in the name input was not properly "escaped" by the software. Thus, when the name is embedded into some SQL statement, the quote is erroneously parsed as a closing quote inside that statement, rather than being parsed as part of the name. Lack of such escaping is a common SQL vulnerability; this type of exploit is referred to as {{w|SQL injection}}.

The name Bobby Tables inspired a website, [http://bobby-tables.com/ bobby-tables.com], a guide for beginning programmers to learn the right way to avoid SQL injection in their code. It appears in [[1253: Exoplanet Names]] as one of the suggested planet names.

===Example of SQL injection===

A typical, unsecured SQL command vulnerable to SQL injection would be something like:

database.execute("INSERT INTO Students (name) VALUES ('" + name + "');");

where <code>name</code> is a variable which is filled with the name to be inserted into the database. With a regular name, this would result in the following SQL command to be sent to the database system:

INSERT INTO Students (name) VALUES ('Elaine');

However, with Little Bobby Tables's full name, the SQL command would be:

INSERT INTO Students (name) VALUES ('Robert'); DROP TABLE Students;--

Or, if split after each <code>;</code>:

INSERT INTO Students (name) VALUES ('Robert');
DROP TABLE Students;
--

The first command inserts the name <code>Robert</code> into the database as in the first example. The second command however completely deletes the table <code>Students</code>. The remainder <code>--</code> is a comment to prevent syntax errors with the apostrophe and the closing parenthesis from the target command that the exploit code otherwise would have no use for.

===Real life occurrences===
In 2017, a Swiss group called their book "<script>alert("!Mediengruppe Bitnik");</script>" to make e-commerce websites display an innocuous pop-up as soon as the book name loads. [https://i.imgur.com/Dd4XN7d.png It immediately worked on several sites] and to this day, [https://www.tomlinsons-online.com/p-16381221-scriptalertmediengruppe-bitnikscript.aspx some websites] are still affected.

In 2019, a person chose a vanity license plate that said "NULL" and subsequently [https://www.wired.com/story/null-license-plate-landed-one-hacker-ticket-hell/ received thousands of dollars in fines from random vehicles] for which the license plate was unavailable. Some database programmers somewhere along the way failed to consider the difference between the string NULL and the value {{w|NULL}}.

In 2020, the British corporate register [https://forum.aws.chdev.org/t/cross-site-scripting-xss-software-attack/3355/8 accepted a registration] for ""><SRC=<nowiki>H</nowiki>TTPS://MJT.XSS.HT> LTD", which was soon officially renamed "THAT COMPANY WHOSE NAME USED TO CONTAIN HTML SCRIPT TAGS LTD" to avoid a cross-site scripting problem.

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[[Category:Characters]]
[[Category:Minor characters]]