explain xkcd - User contributions [en]

2916: Machine

2024-04-09T10:59:28Z

172.69.194.80: /* Toolbox items */ Added space. (And did not know that... Was wondering why there wasn't a chiral opposite. Might be more useful, now!)

{{comic
| number = 2916
| date = April 5, 2024
| title = Machine
| image = machine_2x.png
| imagesize = 740x740px
| noexpand = true
| titletext = The Credible Machine
}}
* To experience the interactivity, visit the [https://xkcd.com/2916/ original comic].

==Explanation==
{{incomplete|Created by a WELL OILED ROBOT. Do NOT delete this tag too soon.}}
This is the 14th [[:Category:April fools' comics|April fools' comic]] released by [[Randall]]. The previous April fools' comic was [[2765: Escape Speed]] from 2023, which was released on Wednesday, April 19, 2023.

Once again an April Fool's Day Comic came out late, as Randall did not release this on April 1st, even though April 1st did fall on a Monday, a normal release day. It first came four days later with the Friday release on April 5th. That this is to be considered an April fools' comic, in spite of the later release, was confirmed on the xkcd Facebook page, see the [[#Trivia|trivia section]] below.

This is a spin on the game {{w|The Incredible Machine}}. The title text explicitly references this, albeit in a linguistic reversal.

Upon loading the page, you are presented with marbles being added to a box by geared wheels, with a button to open a “tool panel”. You are encouraged by Cueball to direct the marbles into a little “output” gear, and told that marbles have a lifespan of 30 seconds to reduce clutter. There are large and small boards available for use, as well as some gimmicky stuff like prisms (which deflect marbles) and fans (which blow marbles around).

The comic starts in a main screen where the user can create a {{w|Rube Goldberg machine}} in a "Cell" where the goal is to route a constant stream of colored balls from an input on the ceiling or a wall to outputs of a matching color on the walls or floor. After the comic is first opened a window pops up over the machine where Cueball in a lab coat tells you to route the balls from the inputs to the outputs. If any balls are left in your cell for more than 30 seconds, they fade away. The first time a ball fades away another popup informs you that the balls are removed for security reasons. When you have built a machine which succeeds in routing enough balls to the output, a popup will prompt you to submit your cell to be added to the public machine.

<gallery heights="200" widths="150">
File:2916_popup_intro.png|Introduction popup
File:2916_popup_time.png|Time limit popup
File:2916_popup_submit.png|Submission popup
</gallery>

The button in the bottom right corner brings you to a page where you can drag around to view all of the machines that have been submitted, with a title for each in the upper left corner. In this view you can see that all of the outputs are also inputs for another cell, except for the top row where the inputs come from off screen and the lowest row which output through a launcher of some kind to a set of four colored-coded containers far below. Any empty cells are marked off by yellow tape with the words "UNDER CONSTRUCTION" as well as "DJIA ↑ 31415" once in each cell. "DJIA" stands for the Dow Jones Industrial Average, with "DJIA ↑ 31415" indicating that it rose to 31415 points, 31415 being the first five digits of pi, without the period.

Under construction cells will feed balls of the appropriate colour into neighbouring cells so long as you are not looking at them. Once you scroll to look at them, the supply of balls stops and subsequent cells in the chain will not receive any; scroll away from them again and the supply will resume.

When you press submit, you will see your creation placed on the grid. However if you refresh that cell will likely be under construction or replaced with someone else's machine. However, other people's machines are consistently placed, so it appears that there is some moderation process selecting a machine for each cell out of the machines submitted by users.

The grid is 12 cells wide, and grows in height. The largest size observed so far is 12x48, for a total of 576 cells. The machine's height is determined by the lowest cell; This can be either your submitted cell, or a cell created by another user.

Whenever balls reach the bottom of the grid, they are directed towards 4 containers, one of each color. Each ball is accurately sent to their appropriate container. These containers are above a pit, and periodically dump their contents. If no balls are directed towards the containers, the pit will be empty. If one or two streams of balls are making it, Cueball and Megan sit in a small boat named the USS Buoyancy. More streams of balls are likely to add more changes.

===Toolbox items===
{| class="wikitable" style="margin:auto"
|+ List of objects
|-
! Description !! Effect !! Image
|-
| Plank || Static || [[File:2916_plank.png|frameless|upright=0.25]]
|-
| Hammer || Static || [[File:2916_hammer.png|frameless|upright=0.25]]
|-
| Sword || Static || [[File:2916_sword.png|frameless|upright=0.25]]
|-
| Hinged scoop || Rotates around its hinge, tries to stay horizontal with a springy effect || [[File:2916_scoop.png|frameless|upright=0.25]] [[File:2916_scoop_mirrored.png|frameless|upright=0.25]]
|-
| Anvil || Static || [[File:2916_anvil.png|frameless|upright=0.125]]
|-
| Brick || Static || [[File:2916_brick.png|frameless|upright=0.125]]
|-
| Fan || Blows away balls in front of it. Different colors are affected by differing amounts (yellow balls are lightest, and can be levitated above an upward-facing fan).|| [[File:2916_fan.png|frameless|upright=0.125]]
|-
| Pillow || Balls will not bounce if they hit it || [[File:2916_pillow.png|frameless|upright=0.125]]
|-
| Round bumper || Bounces balls away at significantly higher speed || [[File:2916_round_bumper.png|frameless|upright=0.125]]
|-
| Triangle bumper left || Bounces balls away at significantly higher speed || [[File:2916_bumper_left.png|frameless|upright=0.125]]
|-
| Triangle bumper right || Bounces balls away at significantly higher speed || [[File:2916_bumper_right.png|frameless|upright=0.125]]
|-
| Attractor/Black Hole || Pulls balls toward center, can be resized || [[File:2916_attractor.png|frameless|upright=0.125]]
|-
| Repulsor/White hole || Repels balls away from center, can be resized || [[File:2916_repulsor.png|frameless|upright=0.125]]
|-
| Prism || "Refracts" balls as they enter and exit || [[File:2916_prism.png|frameless|upright=0.125]]
|-
| Wheel || Spins depending on arrow keys [right/left] pressed while selected (default:anticlockwise), deflects balls, can jam with enough resistance (e.g. glut of balls or against other elements). || [[File:2916_wheel.png|frameless|upright=0.125]]
|-
| "Good job" trophy || Static || [[File:2916_trophy.png|frameless|upright=0.125]]
|-
| Glass cup || Static || [[File:2916_cup.png|frameless|upright=0.125]]
|-
| Cat || Swats away balls in front of themself (was added later) || [[File:2916_cat_new.png|frameless|upright=0.25]]
|}

{| class="wikitable" style="margin:auto"
|+ Characters
|-
! Description !! Image
|-
| Ponytail with raised arms || [[File:2916_ponytail_arms.png|frameless|upright=0.125]]
|-
| Ponytail standing || [[File:2916_ponytail.png|frameless|upright=0.125]]
|-
| Cueball with raised arms || [[File:2916_cueball_arms.png|frameless|upright=0.125]]
|-
| White Hat || [[File:2916_whitehat.png|frameless|upright=0.125]]
|-
| Knit Cap sliding, resting, or floating? || [[File:2916_knitcap_resting.png|frameless|upright=0.25]]
|-
| Knit Cap || [[File:2916_knitcap.png|frameless|upright=0.125]]
|-
| Helmet? || [[File:2916_helmet.png|frameless|upright=0.125]]
|-
| Probably Deterministic sign || [[File:2916_deterministic.png|frameless|upright=0.25]]
|-
| Squirrel || [[File:2916_squirrel.png|frameless|upright=0.125]]
|-
| [[1682: Bun|Bun]] || [[File:2916_rabbit.png|frameless|upright=0.125]]
|-
| Cat || [[File:2916_cat.png|frameless|upright=0.125]]
|}

=== Color routing ===
The different ball colors have different physical properties. Red balls are more bouncy than other balls, green balls are heavier, and yellow balls are lighter and slightly bouncy. The following values were extracted from the code:
{| class="wikitable sortable"
! Color
! Mass
! Density
! Restitution (bounciness)
! Linear damping (drag)
|-
! data-sort-key="00F" | Blue
| 0.08
| 1
| 0
| 0
|-
! data-sort-key="F00" | Red
| 0.08
| 1
| 0.8
| 0
|-
! data-sort-key="0F0" | Green
| 0.75
| 9.325
| 0
| 0
|-
! data-sort-key="FF0" | Yellow
| 0.024
| 0.3
| 0.6
| 2
|}

For certain combinations of inlet and outlet 'gates', it is necessary to 'cross the streams'. e.g. to direct righthand-entry balls to a lefthand-exit and vice-versa. It is possible to just construct the field to send two (or more!) sets of balls to fly across a common gap, to land on an appropriate reception area that leads to the chosen exit. But, though this is not {{w|Proton pack#Crossing the streams|completely inadvised}}, the timing of the balls cannot be guaranteed to be in sync (or, rather, anti-sync) with each other and collisions ''will'' occur, especially under the variations of delivery that might significantly alter the ballistic path across the gap. Even if the trial machine works, in isolation with a steady stream of all balls entering the field of play, once submitted it will inevitably be fed by a more chaotically-routed preceeding construction.

In order to maintain sufficient correct arrivals at exits, it may be necessary to add a method of filtering the hues.

This could just mean introducing a 'wrong hue trap' beyond any crossing point(s) that send the occasionally wrong ball back to the cross point (or let them time-out in a dead-end, relying upon few enough failures from the rest of the balls, along with all colliding balls that subsequently missed ''any'' chance of reaching an exit). Alternatively, two (or more) feeds of marbles could be fed through a deliberate 'sorter' that does a sufficiently reasonable job of separating the combined sets out towards their intended target-exits.

The various physical qualities of the balls suggest a number of methods for redirecting separate hues to separate onward journeys. This can be done by isolating a hue from every other hue, then passing on (if necessary) to a setup extracting a different one from the remainder, and perhaps also a third time. It may also be possible to merge 'arrangements' of sorting mechanics to efficiently distribute straight into three ''or even four'' onward tracks towards the desired outputs, but that is left as an exercise to the reader.


{| class="wikitable"
! style="background-color:black; color:white" | To separate !! style="background-color:lightblue" | Blue !! style="background-color:lightgreen" | Green !! style="background-color:yellow" | Yellow !! style="background-color:red" | Red
|-
! style="background-color:red" | Red
| *R/B* | '''Use 'bounce''''
The sole difference is how much balls will rebound from objects. Well managed and constrained ricochets should allow a sorting action.
| *R/G* | '''Use mass or 'bounce''''
Green balls cannot be levitated by a vertical fan. An incline across any such fan(s) will levitate only non-Greens. Green, like Blue, rebounds differently to Red. Green balls are also effected by black holes much less than all other balls.
| *R/Y* | ''See Y/B''
| *R/R* style="text-align: center; background-color:black; color:white" | n/a
|-
! style="background-color:yellow" | Yellow
| *Y/B* | '''All methods'''
Yellow, alone, exhibits high drag against any unforced motion. It is also unique in all other ways; e.g. can be levitated highest, against all other hues (though most profoundly against Green).
| *Y/G* | ''See Y/B''
| *Y/Y* style="text-align: center; background-color:black; color:white" | n/a
| *Y/R* style="text-align: center; background-color:gray" | ''See Y/B'' 
|-
! style="background-color:lightgreen" | Green
| *G/B* | '''Use mass'''
Green balls cannot be levitated by a vertical fan. There is also a not so marginal difference in density that might be exploited, such as by using black holes, which only minimally effects green.
| *G/G* style="text-align: center; background-color:black; color:white" | n/a
| *G/Y* style="text-align: center; background-color:gray" | ''See Y/B'' 
| *G/R* style="text-align: center; background-color:gray" | See R/G
|-
! style="background-color:lightblue" | Blue
| *B/B* style="text-align: center; background-color:black; color:white" | n/a
| *B/G* style="text-align: center; background-color:gray" | See G/B
| *B/Y* style="text-align: center; background-color:gray" | See Y/B
| *B/R* style="text-align: center; background-color:gray" | See R/B
|}

Even when not strictly necessary for one's own submission, once submitted into the full playing grid the player's own contribution may find itself working with less 'pure' delivered ball-streams (from an imperfectly separating feed-in contribution). It is possible that this more interactive disruption can make the new setup behave erratically or even entirely incorrectly.

It might be thought good practice (but not ''necessary'') to deliberately combine any or all inputs and do a full job of splitting them again, just in anticipation of possibly having to deal with such cross-contamination and being able to 'clean up' the onward stream(s) for the benefit of others. This would of course be particularly difficult if the isolated building-phase does not provide all four hues to 'test' against, so any speculatively added filtering would have to be added 'blind' (and only on the offchance that any anticipated incorrect balls will actually enter the arena) and without any legitimate exits to which such rejects could be shunted (therefore could accumulate, up until any 'time out' that might apply to any ball once operational as part of the combined grid).

Single-input/single-output designs might not particularly require ''any'' sorting mechanism, in theory, though the unexpected 'contamination' of the system with balls of different masses/etc could perhaps introduce malfunctioning passage from the added chaos it might succumb to.

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

:[The placeholder image shows four balls, colored red, green, yellow and blue, bouncing on top of three white blocks. Text in the center: "[visit xkcd.com to view]"]

:[Cueball with lab coat, intro popup]
:Cueball: Balls falling into your cell should be routed to the outputs at a steady rate.

:[Cueball with lab coat, warning popup]
:Cueball: For security reasons, balls that remain in your device for more than 30 seconds will be removed and destroyed.

:[Cueball with lab coat, submit popup]
:Cueball: Congratulations! Your contraption has passed all tests. Press [submit button] to submit it to be added to the machine!

==Trivia==
*Randall acknowledges the people who helped him create this comic in a [[Header_text#Machine|comic-specific header text]].
**With 11 different involved apart from Randall this is by far the comic with most people involved.
*There are some secret key combinations hidden, here are a few of them
**ctrl+alt+b -> follow balls
**ctrl+option+shift+d -> debug overlay
*When Randall posted a [https://www.facebook.com/TheXKCD/posts/pfbid0Cs97awQZi1ZiaEXouAex9tXrwAS3qJV3RmAiuCq5uvZQwqZVMgDmcqJ7JU9LYodYl link to this comic] on his [https://www.facebook.com/TheXKCD Facebook feed], he directly wrote that it was a late April Fools' Day!
**MACHINE
**Happy Belated April Fool's Day!
*This thus ends any discussion of whether this should be seen as an April Fool's comic or not.
**It just came out 4 days late. This has also happened several times since [[Garden]].
[[File:2916 Machine Facebook April fools' confirmation.png]]

{{comic discussion}}

[[Category:April fools' comics]]
[[Category:Comics with color]]
[[Category:Dynamic comics]]
[[Category:Comics with animation]]
[[Category:Interactive comics]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Knit Cap]]
[[Category:Characters with hats]]
[[Category:Squirrels]]
[[Category:Buns]]
[[Category:Cats]]

Talk:2911: Greenland Size

2024-03-26T13:14:53Z

172.69.194.80: ...a whole lotta unsignedness. (Tempted to indent obvious replies, but didn't.)

Anyone else really wanting to know the radius for which the title text is true? I got [[356]]'d
[[User:Rxy|Rxy]] ([[User talk:Rxy|talk]]) 20:28, 25 March 2024 (UTC)

New life goal: Go to the poles, find the ring that is mapped to-scale, and color it. Require all satellite maps to be modified to add this stripe of color. [[User:PotatoGod|PotatoGod]] ([[User talk:PotatoGod|talk]]) 22:37, 25 March 2024 (UTC)

This is clearly based on Lewis Carroll's Sylvie and Bruno Concluded (1893) which discusses a map made at a scale of 1:1. [[User:Take The A Train To Watertown|Take The A Train To Watertown]] ([[User talk:Take The A Train To Watertown|talk]]) 22:49, 25 March 2024 (UTC)

Which latitude of Greenland is 1660miles across? I'm noodling around and can find a spot in the northern part which is - more or less - 1660*km* wide, but nothing close to that number in miles. {{unsigned ip|172.68.144.140|23:01, 25 March 2024}}

Hmm. First time making a comment here, thought that the title text was referencing that the Mercator projection goes to infinity at the poles, and there would be a ring where the map’s unseen parts is 1:1 to the real world. {{unsigned ip|172.71.214.100|01:40, 26 March 2024}}

Yeah, I think the explanation is wrong; there is a ring around the poles which is the same size on the map as it is in real life, because the mercader projection stretches it out. [[Special:Contributions/172.71.150.50|172.71.150.50]] 05:49, 26 March 2024 (UTC)

I'm amazed at how nitpickingly annoying Cueball can get with respect to mapmaking. [[Special:Contributions/162.158.134.38|162.158.134.38]] 08:42, 26 March 2024 (UTC)

"there is a ring around the poles which is the same size on the map" - in standard Mercator projection 1m wide map would need to be kilomenters if not thousands km high to show 1m ring on poles. Usually cutout is at 80-85 latitude {{unsigned ip|162.158.102.110|12:12, 26 March 2024}}

The latitude band would actually be one Earth's radius (6,378 km) high on the map. {{unsigned ip|172.69.223.158|12:36, 26 March 2024}}

2891: Log Cabin

2024-02-12T09:12:03Z

172.69.194.80: /* Explanation */

{{comic
| number = 2891
| date = February 7, 2024
| title = Log Cabin
| image = log_cabin_2x.png
| imagesize = 353x265px
| noexpand = true
| titletext = I'm sure the building inspectors will approve my design once they finally manage to escape.
}}

==Explanation==
{{incomplete|Created by a TRAPPED BUILDING INSPECTOR APPROXIMATELY PI - HEY, COME BACK H! METERS TALL- Please change this comment when editing this page. Do NOT delete this tag too soon.}}

[[File:log_cabin_golden_spiral.png|thumb|301px|Golden spiral (approximately) overlaid on the floor plan]]

This is a comic featuring a {{w|floor plan}}, presumably of a {{w|log cabin}}, and a pun on the word "log". The odd part about it is the right half, which appears to be infinitely recursive copies of the building, a self-similar {{w|fractal}}. The house as a whole represents a {{w|golden rectangle}} with a side ratio of the {{w|golden ratio}} (phi = 0.5 + (1.25 ^ 0.5) ≈ 1.6180339887...), with successively smaller living areas (further subdivided into rooms, to a common but shrunken and rotated plan) being square adjoined by a golden-rectangle of all smaller living areas in the manner of the areas defined by the classic {{w|Golden spiral}} diagram. The joke is that Randall is intentionally conflating the word "log" in the common phrase "log cabin," where "log" refers to the wood the cabin is made of, with a {{w|logarithmic spiral}}, as "log" is shorthand for "logarithm".

Every square subunit of the premises consists of a main combined kitchen/lounge area, with an adjoining shower-equipped bathroom, and a hallway leading to a closet and two bedrooms (a double-bed one with en-suite bath-equipped bathroom, and another with a single bed; both having their own walk-in closet space). Between the kitchen and the dining table is the open doorway that serves as the entry into the next inwards level of the floorplan.

A visitor can also walk in a spiral by using the open doorways in the building plan.

In the title text, Randall says that he is confident that building inspectors will approve the design of his log cabin, assuming they can escape. As one moves deeper into the infinite spiral of architecture, the entire log cabin ''seems'' to be a denser labyrinth of rooms and hallways.

It is unknown how the inspectors lost in the inner rooms would shrink in the same ratio, and would only have to head out through the last doorway they walked in through (or two, if they're currently in the en-suite) and then exit each 'main' area in turn until they exited the building itself. If they have any trouble at all (other than rescaling themselves), it would be that there is ''always'' a further inward area that they might consider needs exploring to fulfil their inspection routine. This construction could imply folded spacetime. To perform a correct inspection, the inspectors might need sufficient relation that inner rooms are identical to the outer rooms, and to solve algebraic equations for various parameters.

In any case, though, they would not need to physically enter the floorplan in order to approve the ''design'', so any risk of getting 'lost' would come solely from a psychological inability to break off from the infinite recursion. Approval of ''construction'' would be a different matter. Whether the floorplan could genuinely be infinitely recursive would depend on how Randall has presented it. Typically, these would be submitted as static images (as it is in the comic), in which case at some point there would be insufficient resolution to continue the recursion, effectively ending in a solid pillar. Randall, however, perhaps channeling his inner Black Hat, may have used a program that dynamically generates further levels as you zoom in to the image.

It could have been that the repetition continued outside of what is drawn here, continuing to grow larger as it moves further out, except that only the top-level external entry has a door: the entries to each lower level only have open doorways marked with no door, and except for the clear marking of external windows on the first four iterations, with no internal ones (and therefore no equivalent windows on the subsequent iterations) precludes that possibility. In fact, the first iteration has windows on the 'southern' edge for the single bedroom and seating area, for which there are no equivalents on any of the other iterations.

[https://www.generations-quilt-patterns.com/log-cabin-quilt-block.html Log Cabin] is also a classic quilting block, which starts with a tiny square and spirals outwards.

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

:[A drawing of the top view of a log cabin, which includes two beds, a kitchen, a bathroom and furniture. A smaller version of the log cabin is connected to the main building. An even smaller version is connected to the smaller version, and so on, forming a golden rectangle.]

:[Caption below the panel]:
: Log cabin

{{comic discussion}}

[[Category:Engineering]]
[[Category:Math]]
[[Category:Puns]]

1102: Fastest-Growing

2024-02-06T22:05:47Z

172.69.194.80: /* Explanation */ Regarding the Talk request. Changing the link text seemed more insulting than expanding.

{{comic
| number = 1102
| date = August 31, 2012
| title = Fastest-Growing
| image = fastest_growing.png
| titletext = I lead a small but extraordinarily persuasive religion whose only members are door-to-door proselytizers from other faiths.
}}

==Explanation==
This comic talks about the misuse of percentage of growth. It can be misleading for gauging the importance or popularity of something; If you add only 4 members to an existing group of 2, you would have achieved a growth of 200 percent.

In the case portrayed in this comic the claim appears to be that the other person's religion grew by 85%. [[Black Hat]] attempts humorously to show the flaw in using that statistic by growing his group by 100% (therefore, presumably, first place), which he simply does by adding his friend [[Rob]] to his religion, and thus increasing his membership from 1 to 2. The other person then says that his religion has a significant number of members (and not just one or two, but ended up with 38,000 this year, presumably having 'only' around 20,540 in the prior one), but Black Hat doesn't care and responds that he hopes they are all okay with being "in second place" since the main argument from the other guy was about being the fastest-growing.

The title text ponders the ironic idea of converting ''only'' the zealous door-to-door {{w|Proselytism|proselytizers}} to a very persuasive religion of one's own.

Another interpretation is that the title text could be another way that Black Hat could take the 'fastest-growing' claim out of context to make it meaningless. By composing his religion of the unwitting proselytizers of other faiths, he can claim the highest ratio of converts to current adherents. Note that the amount of people converted is often exaggerated by groups that try to spread a faith. Although the beliefs spread by his proselytizers vary widely, Black Hat is not concerned with what his so-called followers believe. Thus, he can claim the title of fastest-growing religion without having any value to his religion.

Various religions and groups encourage their members to actively recruit new followers, such as the {{w|Mormon missionary}} (or "Missionaries of the Church of Jesus Christ of Latter-day Saints", to use their own more acceptable full name).

==Transcript==
:[A man with a combover, a book, and a clipboard approaches Black Hat.]
:Combover: You should check us out. We're the fastest-growing religion in the country.
:Black Hat: "Fastest-growing" is such a dubious claim.
:Combover: It's true! We grew by 85% over the past year.

:[In a frameless panel, Black Hat shouts to Rob, out of frame.]
:Black Hat: Hey, Rob — wanna join my religion?
:Rob's off-frame voice: Sure, whatever.

:[Black Hat turns back to Combover and produces a notepad and pen.]
:Black Hat: Well, looks like my religion grew by 100% this year.

:[Black Hat begins to walk away.]
:Combover: We have 38,000 members!
:Black Hat: Hope they're all ok with second place.

{{comic discussion}}
[[Category:Comics featuring Black Hat]]
[[Category:Comics featuring Rob]]
[[Category:Religion]]
[[Category:Statistics]]

Talk:2466: In Your Classroom

2024-02-04T13:57:02Z

172.69.194.80: Fix info reply.

yay! another one where a table is useful for an explanation! also first ALPHALUL [[Special:Contributions/162.158.79.59|162.158.79.59]] 01:01, 22 May 2021 (UTC)Bumpf

Exobiology should not be in the Good area. I've seen those movies, I know what happens next. [[User:Andyd273|Andyd273]] ([[User talk:Andyd273|talk]]) 02:18, 22 May 2021 (UTC)

I'm sort of sad that the the hover text, or perhaps the origin, wasn't simply "Tautology" [[Special:Contributions/108.162.237.74|108.162.237.74]] 21:01, 22 May 2021 (UTC)

I think that the scales would be better shown as +/- from a (0,0) point than %'s from the top left. At least for the Good/Bad axis It's really weird to say that "Education" has 10% ''danger'' because it's not quite as good as having an atmosphere. Is it just me? --[[User:Bobson|Bobson]] ([[User talk:Bobson|talk]]) 01:51, 23 May 2021 (UTC)
:Many students consider education - especially tests - dangerous. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 02:26, 23 May 2021 (UTC)
:No, I agree as well. Would it be out of line if I changed it? [[Special:Contributions/162.158.75.18|162.158.75.18]] 17:26, 25 May 2021 (UTC)

Not sure how big is smallest quasar, but I suspect one appearing in class would be bad even for Sun and rest of solar system. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 02:29, 23 May 2021 (UTC)
:I agree. This should be sooooo far below the bad axis (or Volcanoes) that it should only have been mentioned in the title text. Of course Quasars do not exist in this age... But if one suddenly began in your class room it would be the end of the local spiral arm of the galaxy, and would devour most of what was there forming a new black hole center of the galaxy (a double black hole center). It would of course end all of Earth history as well as the solar system and the local cluster of stars. So putting it right under volcanoes, which would only destroy the local city (it was not given it was a super volcano), compared to ending Earths existence is not really serious. And as explained in the explanation he has previously also mentioned off chart points in the title text, as he does also for less interesting subjects in this one as well. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 19:06, 24 May 2021 (UTC)

Is vertical axis how dangerous? I read it as either being positive utility (Societal good and bad) or how much Randall likes it? [[User:Kev|Kev]] ([[User talk:Kev|talk]]) 10:19, 23 May 2021 (UTC)

Shouldn't it be vulcanology?[[User:Joem5636|Joem5636]] ([[User talk:Joem5636|talk]]) 12:33, 24 May 2021 (UTC)
:I thought that, but it appears that vulcanology/volcanology are both possibly equally valid (though the 'vulc' definitions point to 'volc' ones almost always in online dictionaries, with the reverse mostly only as 'alternative', and 'vulcanologist' seems less acknowledged than 'volcanologist' in related-words linking). In many ways, that annoys me, but that might be the classicist in me rather than the geographer/geologist who appreciates that "vulcanology" might be a rather more limited field that would require no more travel to extensively study than can be afforded by a handy Sicilian fishing boat or light aircraft. [[Special:Contributions/141.101.99.19|141.101.99.19]] 14:48, 24 May 2021 (UTC)

Would an alternate Geography = weird be due to an invading nation-state? We already have volcanology and other similar "The earth came into the classroom" things in the graph. [[User:OhFFS|OhFFS]] ([[User talk:OhFFS|talk]]) 21:42, 24 May 2021 (UTC)
:That would be bad, but still less weird than the actual Earth. [[Special:Contributions/172.70.114.48|172.70.114.48]] 18:09, 26 May 2021 (UTC)

TL;DR: Too many "citation needed" tags! It's not funny if you use it too much.

Several parts of this explanation seem to have been written in such a way as to include statements against which nobody in their right mind would argue and, in any other context at least, would not require any supporting citation, and are hence appropriate places for the humourous use of "citation needed" often seen on this site.{{citation needed}} I very much appreciate the hitherto typical Explain-XKCD-style sparse (about once per article) use of "citation needed" but I feel that it loses much of it's comedic effect when used frequently (six times in this article as I write!) in text that appears to be composed with the purpose of including the tag several times. I appreciate that some of us enjoy reading explanations peppered with the tags, so I haven't removed any of them, but my feeling is that the 'too much of a good thing' concept applies here. In future articles I personally hope to see normally written explanations (or as normally written as we can reasonably expect given the subject matter) with "citation needed" tags used only sparingly.

Missed opportunity: "...and Quantum Mechanics is both way off to the left and way off to the right." --[[Special:Contributions/172.69.35.102|172.69.35.102]] 22:25, 1 June 2021 (UTC)

I tried to edit the table to have the weirdness and badness from -10 to 10, but the table broke. Can someone fix it please? [[User:Cal3000000|Cal3000000]] ([[User talk:Cal3000000|talk]]) 12:12, 4 February 2024 (UTC)
:Fixed it [https://www.explainxkcd.com/wiki/index.php?title=2466:_In_Your_Classroom&diff=334172&oldid=334170 here] (before I read your call for help). I mention in the summary the ''reason'' it broke, and was just about to let you know anyway (you don't have a Talk page yet, so came here to give the link and then find the above plea).
:(I had to squash the reason down, to fit, however. Table-data lines get the "|-" symbol at the start of a line (text after that doesn't appear as regular cell data). Table cell-data starts as "|" on a line-start (or "||" where adding more cells on a single line of markup) and when the cell ("|") starts with a "-" (e.g. "-5") then it clearly looks like a row-break ("|-[...]") unless you do something about it. In this case, I put a space between the cell-pipe and the value-negative (and also could have added one, or two, before the unsigned values ...just for markup neatness). Other solutions might have been to use a different dash (”–” instead of "-", visually not too different, but might have annoyed other people doing text-sesrches), moved the new-line cells into being "||" followups to the respective prior line or used something like a <code><nowiki><nowiki/></nowiki></code> "breaking-nonspace" interjection (i.e. technically the opposite of an <code>&nbsp;</code>, though that would have worked also for several reasons). I'm sure there are other ways of doing it, as well, but I only tried the first, with the others in mind in case I'd got the right sort of diagnosis in mind but hadn't immediately identified a working cure.)
:The only suggestion I have, for future, is to use the Preview button more. As I ought to, sometimes. But it lets you play around to see if you can identify (and solve!) any problems, especially with notoriously miseditable table markup. You can also entirely back out of changes easier, while you try to learn what went wrong or seek help from others. It's always good to learn, of course! And I also learnt from this, and it's probably only circumstantial that I had never made the same inadvertent error in the past... ;) [[Special:Contributions/172.69.194.80|172.69.194.80]] 13:57, 4 February 2024 (UTC)

Talk:2761: 1-to-1 Scale

2023-04-11T20:35:01Z

172.69.194.80:

Really want an explanation for this one. [[User:JobbieJimmies|Melomaniac]] ([[User talk:JobbieJimmies|talk]]) 03:23, 11 April 2023 (UTC)

My comment got deleted by a bot!!! [[User:Unreliable Connection|2659: Unreliable Connection]] ([[User talk:Unreliable Connection|talk]]) 03:23, 11 April 2023 (UTC)
:RIP... [[User:JobbieJimmies|Melomaniac]] ([[User talk:JobbieJimmies|talk]]) 03:25, 11 April 2023 (UTC)
:No, UC, it just got overwritten by the 'bot, when it did its job and (re)created the whole initial state of the various pages to depict the new comic coming out. (Noting that you'd not set them all up fully/correctly.)
:That you had spotted it already and had ''just'' gotten in ahead of the 'bot clearly isn't something it was prepared to handle. But as someone spotting it can usually wait a short while for the 'bot to catch up, I don't think it's a problem. In fact, you could have just copied your old contributions into the now receptive page(s), with nary any comment. Too late now. [[Special:Contributions/172.70.90.101|172.70.90.101]] 03:44, 11 April 2023 (UTC)

:: This may have broken the next link on the previous page. --[[Special:Contributions/172.71.160.36|172.71.160.36]] 06:41, 11 April 2023 (UTC)

The lines represent the surfaces of the planets I think, so it's basically all the planets overlaid on top of each other. [[Special:Contributions/172.71.142.35|172.71.142.35]] 03:28, 11 April 2023 (UTC)

:Yup, I think it's what he meant - but I find it unlikely that the gas giants would have this clear cutoff of a "surface". [[Special:Contributions/162.158.189.241|162.158.189.241]] 03:34, 11 April 2023 (UTC)
::If there is a gas - liquid phase transition (and I think at least the gas giants have them): Why not? OK, you could see "rain" as blurring a clear cutoff, but wouldn't that also apply to Earth, then?[[User:Tier666|Tier666]] ([[User talk:Tier666|talk]]) 08:04, 11 April 2023 (UTC)

I’d think the same citation as stands for ridiculously large would also cover larger than currently exists on earth, and his that citation is not in fact needed? [[Special:Contributions/162.158.174.186|162.158.174.186]] 06:53, 11 April 2023 (UTC)

:It seems like the gas-covered worlds are explicitly those with clearly cutoff "surfaces," so maybe in those cases the cutoff is some specific gas density -- which occurs at a consistent radius throughout the planet, thus creating a flat surface. While for rocky worlds (except Venus, which is treated like a gas planet here), a density cutoff can lead to bumpiness due to terrain. [[User:Trimeta|Trimeta]] ([[User talk:Trimeta|talk]]) 03:57, 11 April 2023 (UTC)
:: just to be very clear (this being a explanation site!) that Venus is "treated like a gas giant" because of it's thick atmosphere. It would be just as correct to say "All the gas giants are treated like Venus" After all, ordinary telescopes couldn't take a picture that sees through any atmospheres, except Earth, where you'd see clouds but often surface where clouds don't appear. Sorry if that's an overexplanation [[User:Cuvtixo|Cuvtixo]] ([[User talk:Cuvtixo|talk]]) 19:10, 11 April 2023 (UTC)

On Twitter there seems to be concern that all planets are depicted flat. This may make this a contribution/mockery of the ongoing [https://en.wikipedia.org/wiki/Flat_Earth Flat Earth] discussions in some corners of the internet. --[[Special:Contributions/198.41.242.132|198.41.242.132]] 06:49, 11 April 2023 (UTC)
:You can't see the curvature of the Earth when standing on it; doesn't mean it's flat. Since we're looking at the planets at a 1:1 scale, we're literally only seeing a couple of inches of each of their edges (notwithstanding the whole gas-giants-don't-have-a-sharp-edge issue). [[Special:Contributions/162.158.239.20|162.158.239.20]] 12:06, 11 April 2023 (UTC)
:actually you can see it, standing on the shore of any large lake on a calm day looking at a shore that's ~6.5 miles (10.5km) away. You'll lose ~8ft (2.5m) below the horizon - [[Special:Contributions/162.158.186.213|162.158.186.213]] 13:55, 11 April 2023 (UTC)

The display for an uncropped version of the image would not only be larger than any display on earth. It would be larger than earth. [[Special:Contributions/162.158.86.243|162.158.86.243]] 06:59, 11 April 2023 (UTC)
:By necessity, at least as large as Jupiter. Maybe slightly above two Jupiters (max dimension squared compared to display height*width of any common aspect ratio) if you wanted to not overlay any of the others at all. And make the lower limit a packing-problem, then add a buffer so there isn't the actual need for any to touch. [[Special:Contributions/172.70.90.253|172.70.90.253]] 10:02, 11 April 2023 (UTC)
::I'm going to add that. Someone was confused enough to put {{cite needed}} there, which may be a joke onto itself?, I can't tell. I've removed the cite needed, but I guess it needs to be more clear why it's totally nonsensical and doesn't need a citation? [[User:Cuvtixo|Cuvtixo]] ([[User talk:Cuvtixo|talk]]) 19:16, 11 April 2023 (UTC)

1-to-1 scale means 'assume all planets are the same size,' right? I see Earth's grass is shown to be as large as Martian rocks, because Earth is a third again as large. (At the scale where grass is visible, Earth looks flat.) At first I thought the point was that altitude variation in cloud-tops varied so little that a gas giant shrunk down to Earth size would be featureless and have a distinct edge, but that's wrong. Ground isn't cloud-tops. Do gas giants have any solid ground? We've seen Jupiter eat comets, and it makes sense they would've collected at least some minerals and metals. According to [[https://www.teachastronomy.com/textbook/The-Giant-Planets-and-Their-Moons/Internal-Structure-of-the-Gas-Giant-Planets/|Teach Astronomy]], gas giants have Earth-sized solid cores. I'm guessing gas giants' immense gravity compresses their cores into featureless spheres, which, if scaled to Earth-size and viewed at the scale where one could see grass, would look flat. Yes?
[[User:EllenNB|EllenNB]] ([[User talk:EllenNB|talk]]) 10:14, 11 April 2023 (UTC)
:Gravity itself won't compress (and 'flatten') the cores. "Shell theory" shows that gravitational force only counts from the proportion of the body that is within the radius of the bit you're concerned with. But there'll also be the external pressure (from being at the bottom of a thick atmosphere that ultimately ''is'' above far more of the planetary mass) and possibly a degree of compression density to make any Earth-sized core slightly heavier than if it was just a bare core of the same size but shorn of outer layers.
:As to flatness, I can take you to very flat stretches of Earth and very lumpy bits (depends which direction I go, from where I am now), all within 30 minutes' drive. We can'teven know how representative a sample of planetary cross-sections we are seeing (once we get over the issues of gas/space boundaries for gas-giants), but I bet there are bits that resemble the diagram... If you ''really'' want it to be so real. [[Special:Contributions/172.71.242.87|172.71.242.87]] 11:05, 11 April 2023 (UTC)
:No, 1-to-1 means that they are actual size, not the same size. [[User:SDSpivey|SDSpivey]] ([[User talk:SDSpivey|talk]]) 13:37, 11 April 2023 (UTC)

There are several pieces of information here that are featured but don't make sense to me. What's the function of the dark polygon in the center? Why are the lines showing each surface going in random directions? Why is the surface of each planet so flat at a full scale rendition? When I look out my window at full sized Earth, it's not flat. It's quite bumpy, actually. But perhaps he doesn't mean these are full size, he might be saying that they're all shrunk, but the same amount, so 1:1:1:1:1... but even then, I'm totally lost.

"What's the function of the dark polygon in the center?"
I think it is a view of the dark sky, "above" the surface of the Earth, Mars, etc. [[User:Rps|Rps]] ([[User talk:Rps|talk]]) 11:43, 11 April 2023 (UTC)
:I think the "polygon" is a grassy Earth itself, with the white above it sky. Earth is the rearmost planet pictured. Then in front of Earth, on all sides except the top, are the overlays of the various planets, what little of each one as can fit. But then maybe the polygon is night starry sky, and Earth is the white area above it. [[User:N0lqu|-boB]] ([[User talk:N0lqu|talk]]) 14:35, 11 April 2023 (UTC)

Is this an ant on earth, over the letters "EA" ? On my monitor, set for my less-than-perfect vision, it is 15mm long, which (at a 1:1 scale) makes it a cow ant, or a large african ant. I guess people with normal vision get fire and carpenter ants instead? And those on smartphones get pavement ants?[[Special:Contributions/172.68.50.73|172.68.50.73]] 11:00, 11 April 2023 (UTC)
:I do believe it is! It's 6 mm on my desktop monitor and 3 mm on my phone. We also don't know what side of the Earth we're looking at, so I suppose it could really be any ant, including the one in your local area. I like to think it's a black garden ant (''Lasius niger''), since I'm most familiar with those :) [[Special:Contributions/162.158.239.25|162.158.239.25]] 12:16, 11 April 2023 (UTC)

It took me a good while to figure out this one; I don't normally need to come here, but this one stumped me at first. (The comments as of right now weren't too illuminating either.) I think the lack of color was an issue; I first thought the black polygon in the center was the earth, and then interpreted the various lines as a really weird diagram type I'd never seen before, like a phase diagram or something; I also considered one-dimensional planets. [https://imgur.com/a/yJOYvk1 I colored in the planets to aid me.] The way I now interpret this one is thus: imagine an observer sitting a tremendous distance away from the solar system, and they have a camera with an extremely supremely highly zooming telephoto lens. Then a lining-up of all eight planets happens – I believe this is impossible IRL (because of resonances or something), but just go with it. The observer manages to snap this incredible image of a teeny tiny spot of the sky, which simultaneously manages to include the very very edges of all the planets as well as some of the sky behind them all. The sky is the black polygon: it has nebulae and stars. Neptune is in front of Uranus, and that as well as Mercury are in front of Saturn, which is in front of both Jupiter and Mars; Venus is between Mercury, Mars and the Earth, and the Earth is also behind Jupiter. The reason why these are all so smooth is because it's such a small area: we're literally only seeing a couple of square inches of the surface of each of the rocky planets. (See, you can see an individual ant on the Earth. Go to the most rugged mountain range you can find and observe a couple of square inches; it'll be locally flat.) The lack of atmospheres on the rocky planets as well as the hard edges of the gas giants are artistic license. This one is a member of the genre of "true yet unhelpful diagrams"; I'm surprised that isn't a category on this wiki. – [[Special:Contributions/162.158.238.4|162.158.238.4]] 12:58, 11 April 2023 (UTC)

((Written whilst 162.158.238.4 was editing, above, and I got an edit conflict on that. The editor concerned touches on this ordering business, but I'm pasting my original in unaltered, not rejigged as a more focused reply.)) I was wondering abut the "overlap order" for a while, until I twigged it. May not be worth officially documenting, but my analysis, showing that (perhaps depending upon specific orbital positions, during a given range of times, which can of course be checked) it's ''probably'' based upon distance away from Earth.
*Earth is bottom-most. Could be 1st/2nd, shared with Mars, as their overlap isn't shown.
*Mars is our nearest neighbour. (As above, could be 1st ''or'' 2nd on stack.)
*Venus next. Although it could be 7th (only obscured by Mercury) or anywhere else down to 3rd.
*Jupiter as 4th from bottom. (''Could'' be 3rd..5th, though.)
*Saturn takes 5th-up position. (4th..6th)
*Mercury as 6th. (Or all the way to topmost, but I made an assumption about its relationship to the last two.)
*Uranus as 7th. (6th/7th a possibility, depends on Mercury)
*Neptune as 8th. (7th/8th possible, Mercury again.)
...or at least that's what my mental notes tell me. Not helped by starting off counting from near to far and possibly messing up my numbers when I realised it made sense to flip them. It could also be "delta-V needed to reach the planet concerned" (either without or ''including'' flyby slingshot momentum borrowing/burning), but that's something I'd also need to check. I doubt it really needs tying down/Explaining, and when I edited the Transcript I decided not to record every nuance of the "variously orientated surfaces", as I think it adds nothing so long as the description gives the general idea. [[Special:Contributions/141.101.98.121|141.101.98.121]] 13:06, 11 April 2023 (UTC)

So no one is going to mention that for the clarity depicted you'd need to literally place the planets inside of each other, or have some sort of focal length from zero to infinity? I'm not sure if that bothers me more or less than the missed trick of making the length of ground shown relate to some comparative parameter (albedo might have been a fun one) - [[Special:Contributions/162.158.186.213|162.158.186.213]] 13:55, 11 April 2023 (UTC)
:To be fair, you're also going to have to choose a "flat" few inches of surface that stands proud of the local geography (such that anything higher is below the curvature of the Earth for its proximity), and deal with an impossible resolution of an impossibly zoomed telephoto shot from a viewpoint unimaginably distant (''whilst'' a near-enough non-Solar conjunction/asterism is happening, or at least was, when the light passed each body), without significant atmospheric distortion (which is a relatively minor issue, compared with the scarcity of photons that reach the camera ''anyway'').
:Can we perhaps instead assume that these are just individual 1:1-scale cross-sectional diagrams (or even carefully curated local photos) drawn together into a hybrid image to accurately retain the scaling verisimilitude, and individual contexts, but happily faking the relative positions? [[Special:Contributions/172.70.85.56|172.70.85.56]] 15:00, 11 April 2023 (UTC)

It would take some work to check, but I'm wondering if the angle of the horizons of the various planets are perpendicular to the line made between the earth and the planet in question [[Special:Contributions/162.158.154.141|162.158.154.141]] 15:36, 11 April 2023 (UTC)

This is how I interpret this image: [https://imgur.com/a/WwdbXkN I didn't want to make the black dot as small as in the picture so dimensions are insanely larger] [[Special:Contributions/172.69.194.80|172.69.194.80]] 20:35, 11 April 2023 (UTC)