explain xkcd - User contributions [en]

3078: Anchor Bolts

2025-04-22T08:35:03Z

172.70.162.62: /* Explanation */

{{comic
| number = 3078
| date = April 18, 2025
| title = Anchor Bolts
| image = anchor_screws_2x.png
| imagesize = 381x326px
| noexpand = true
| titletext = The biggest expense was installing the mantle ducts to keep the carbonate-silicate cycle operating.
}}

==Explanation==
{{incomplete|Created by an AUTOMATIC SUBLIMATOR. Don't remove this notice too soon.<br/>Need to rephrase a section, see the talk page.}}

The comic displays a cross-section of a subduction zone, with an anchor bolt connecting the two tectonic plates. {{w|anchor bolt|Anchor bolts}} are used to secure an item in place, for instance to attach a building to its foundation. In earthquake prone areas, anchor bolts are often used to secure furniture so it will be less hazardous during a tremor.

{{w|Subduction}} is a geologic process in which two {{w|Plate tectonics|plates}} of planetary {{w|lithosphere}} converge, and one is dragged under the other. The Earth's lithosphere is divided into tectonic plates. They slowly move across the surface at a few centimeters per year, although the rate is nonuniform across plates. Where they collide, the denser plate gets dragged under the less dense plate, in a process called subduction. {{w|Earthquake|Earthquakes}} are common at subduction zones, and subduction can also lead to volcanic activity. An "anti-subduction anchor bolt" would aim to stop the process of subduction and the movement of plate tectonics as a whole.

A round head bolt is screwed in through both the oceanic lithosphere and the continental crust from the bottom up, with a plain washer on either side, and a wing nut tightened at the surface. Washers are present to prevent the bolt and the wing nut from sinking into the crust, by distributing the forces over larger areas. There are several concerns not addressed in the comic with such a design. The implication that the bolt is being screwed in from the mantle side would imply that a very large bolt head was operated from inside the mantle. (There are types of nut-and-bolt system that might be easier to deploy, such as {{w|toggle bolt}}s and {{w|Molly (fastener)|mollys}}. These would have the bolt head on the Earth's surface, rather than in the mantle, and use a spreading "nut" inside the Earth. They wouldn't require conducting enormous operations from below, "merely" a large hole bored from above.) As of the time of posting of the comic, {{w|Kola Superdeep Borehole|humans have not drilled a hole through a continental crust}}, still less deployed large vehicles in the mantle.{{Citation Needed}} In addition, the presence of wing nuts, fasteners that are designed to be able to be screwed in by hand, implies work done by a larger being that has appendages able to use the wing nut. The bolt itself would be a technological challenge, as well. It would need to be made to withstand the temperature of Earth's mantle, around 1000°C near the surface. At these temperatures, most commercial stainless steel used to manufacture bolts would experience noticeable strength losses. The bolt would need be around 50 km long. Moreover, as subduction zones move parallel to each other, the construction would have to withstand high shear forces, something that a bolt is rather unsuited to compared to other tools, such as rivets. On top of that, ways to alleviate stress must be sought out as if the bolt fails, it could produce a highly amplified earthquake.

In the short term, earthquakes and volcanic eruptions are typically bad for those living nearby, and thus ways to prevent them happening might reduce economic risks in those areas. However, volcanic eruptions deposit nutrients in the surrounding area, enriching soils. Volcanos also release gasses. The vents mentioned in the title text might replenish the nutrients and gasses, replacing the benefits of eruptions. Earthquakes sometimes trigger {{w|tsunami|tsunamis}}, which create or modify beaches, and redistribute nutrients from bays and estuaries across coastal plains. So, while the immediate effects of eruptions and earthquakes can be disruptive, they also enrich the environment. Areas at risk from these "disasters" are also attractive and enriched as a result of these same events.

When plates collide but do not subduct, they often uplift, thickening or raising the crust. The {{w|Himalayas|Himalaya}} mountains, are an example. Tectonic plates spread apart as new lithosphere is formed at ridges, most of which occur under oceans. If spreading continued, but subduction was prevented by the system of anchors pictured in this cartoon, there would likely be new areas of uplift. If positioned appropriately, the mantle ducts, mentioned in the title text, might slow or stop the spreading, reducing uplift.

The title text references the {{w|Carbonate–silicate cycle|carbonate-silicate geochemical cycle}}. Briefly, subduction and subsequent heating of the global crust restores carbon dioxide and silicate rocks to the planetary surface, countering the effects of carbonate deposition and silicate rock weathering. Anchor bolts sufficient to stop plate tectonics would also stop the carbonate-silicate cycle, leading to unexpected, and likely unwelcome, changes in the surface geosphere and biosphere. (Arguably, if the carbonate cycle alone could be paused, it might be a means of reducing the amount of carbon dioxide in the biosphere.) To restore the cycle by an unknown mechanism, "mantle ducts" have been installed as part of the planet-wide plate anchoring system. It is stated that the mantle duct installation was the most expensive part of the project, implying greater intellectual and technical challenges than the already-massive ones associated with anchor-bolt design and deployment.

This project would presumably render [[Beret Guy]]'s [[1388|Subduction License]] worthless.

==Transcript==
:[Panel shows Randall's usual illustration of a subduction zone: a tectonic plate subducting from the left side of the panel with water above it, and a mountain range forming on the right side of the panel on the other tectonic plate. Beneath each tectonic plate is the asthenosphere. The main difference between this image and others like it is that there is a bolt shown attaching the plates together in the subduction zone. The head of the bolt is shown in the asthenosphere below the subducting plate. There are two washers displayed, one between the bolt head and the subducting plate and one above the other above the upper plate on the side of a smaller mountain. A wing nut is positioned above this washer, with part of the bolt sticking out above the nut, higher than the tallest mountains in the panel]

:[Caption below the panel:]
:Good news: Geophysicists are '''''finally''''' installing Earth's required anti-subduction anchor bolts.

==Trivia==
In the [https://www.explainxkcd.com/wiki/images/archive/0/00/20250419063115%21anchor_screws_2x.png original version of the comic], the caption said "anti-subduction anchor '''screws'''" instead of "anti-subduction anchor '''bolts'''". The title of the comic was also changed, from "Anchor Screws" to "Anchor Bolts". The original comic image and title can be seen on an [https://web.archive.org/web/20250419024242/https://xkcd.com/3078/ archived version] of the [https://xkcd.com xkcd.com] site. The fastener illustrated is indeed a {{w|Bolt (fastener)|bolt}} (with a {{w|Wingnut (hardware)|wing nut}}), not a screw. A screw has a pointed end and is drilled into a hole that is smaller than the diameter of the screw; the pressure caused by its {{w|screw thread|thread}} and screw head binds two objects together. A screw does not need a nut to go with it.

A bolt has a flat end, and it goes into a hole that is larger than the diameter of the bolt; it needs a nut which, when fixed onto the bolt and tightened, together with the head creates the pressure that binds the two objects together. Because a nut is used to create pressure, "bolt" is a more correct term than "screw", although it is very common to talk of 'screws' for [[1474: Screws|screw-headed]] bolts which attach panels (with non-threaded holes) against a substrate which incorporates a 'nut-like' threaded hole within it (or a nut encapsulated and held non-rotating in the backing plate's recess), even though they are also flat-faced at the thread-end and not self-tapping.

Or, for a differently worded definition, {{w|Screw#Differentiation between bolt and screw|see here}}.

{{comic discussion}}

[[Category:Subduction]]
[[Category:Geology]]
[[Category:Comics edited after their publication]]

Talk:2795: Glass-Topped Table

2023-07-03T09:18:38Z

172.70.162.62:

First! [[Special:Contributions/172.71.167.52|172.71.167.52]] 19:01, 28 June 2023 (UTC)

How is "glass-topped" not a term found often online, yet I'm so used to calling it that in verbal conversation (Western Canadian, for reference). Searching for "glass-topped" (with quotes) shows this comic first in results (past ads) :) [[Special:Contributions/162.158.146.105|162.158.146.105]] 19:09, 28 June 2023 (UTC)
:Its probiably just your search personalization. My first search result https://www.designtoscano.com/categories/glass-top-accent-tables followed by xkcdexplained, xkcd, walmart, etsi, and commercial-interiorsuk.com (boy talk about a sus URL). [[User:Jamcdonald|Jamcdonald]] ([[User talk:Jamcdonald|talk]]) 09:21, 29 June 2023 (UTC)
It's not "instead of" -- the table has both a glass surface and a drinking glass. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 19:32, 28 June 2023 (UTC)

…You could always hand-wash the cup. [[User:PxP|PxP]] ([[User talk:PxP|talk]]) 19:45, 28 June 2023 (UTC)
:Not sure about you, but when I hand-wash something, I'm doing it over sink. Getting the table to sink would be quite hard, although probably easier than fitting it into dishwasher. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 22:18, 28 June 2023 (UTC)
::It would also be difficult to pour out either the drink or the washwater.[[Special:Contributions/172.69.247.51|172.69.247.51]] 23:46, 28 June 2023 (UTC)
:::Pressurised water... If you have anything hose-like (or it's within range of one of those extensible tap-attachments) then gush water into it and anything not actually stuck to the glass (any really gloopy liquid - like a partly dried old smoothie left there too long that may need a bit of mechanical wiping too) gets diluted and pressured out. (...Onto the floor, unless you are prepared for that.)
:::A quick rub with a dishcloth can wick up most of what doesn't jump straight back out (you need a quick shut-off to the water supply, ideally, so it doesn't dribble-fill so much, anyway) and if it was hot enough then the last bits of dampness 'self dry'. [[Special:Contributions/172.70.162.159|172.70.162.159]] 01:18, 29 June 2023 (UTC)
::You drag all your furniture, tables, chairs, whatnot, to the sink to wash them? I've never heard of people who don't just bring cleansers/water and paper towels/sponges TO their furniture... :) [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 04:26, 2 July 2023 (UTC)

Some of the unpopularity probably comes from it being halfway off of the table, giving you the ever-present feeling that it might fall. [[User:TheLittlePeace|TheLittlePeace]] ([[User talk:TheLittlePeace|talk]]) 19:50, 28 June 2023 (UTC)

Some seemed to have missed the real point; this is a cat torture device. I can just see my moggy lying there kicking at it for hours. [[Special:Contributions/172.69.34.131|172.69.34.131]] 04:34, 29 June 2023 (UTC)
:Cat torture device? I could see it being their main entertainment, depending on temprement... [[Special:Contributions/141.101.98.126|141.101.98.126]] 11:24, 29 June 2023 (UTC)
The torture aspect causes me to doubt that this is anywhere close to the least popular. We've seem the style he has in furniture. I bet there is no couch, it's just offered so that people don't get upset.

Are there really dishwashers large enough to fit an average dining table? The link in the explanation refers to an advertising installation that specifically does not work as a dishwasher. It was designed to keep objects inside it dry. [[User:Bischoff|Bischoff]] ([[User talk:Bischoff|talk]]) 07:01, 29 June 2023 (UTC)
:There are, this one should do the trick https://www.webstaurantstore.com/champion-pp-20-split-door-pot-and-pan-washer-208v-3-phase/253PP20SDC.html [[User:Jamcdonald|Jamcdonald]] ([[User talk:Jamcdonald|talk]]) 09:25, 29 June 2023 (UTC)
This has to be a cat's worst nightmare... [[Special:Contributions/172.71.94.137|172.71.94.137]] 08:46, 29 June 2023‎ (UTC)
:(Doom music starts playing) [[User:Fephisto|Fephisto]] ([[User talk:Fephisto|talk]]) 19:58, 29 June 2023 (UTC)
This is my first ever edit, so forgive me if I don't sign it correctly, but I felt compelled to create an account in order to share that this comic very much reminded me of The Uncomfortable (https://www.theuncomfortable.com/). Don't know if this belongs in the main explain page, but thought I'd share it here and let someone else decide. [[User:dominiclipari|dominiclipari]] 12:55, 29 June 2023 (UTC)
:"...so forgive me if I don't sign it correctly" - close enough, but I suspect you wrote (most of?) it manually. Just put the <code><nowiki>~~~~</nowiki></code> in (or press the penultimate button in the line of buttons immediately above the textediting area) and you should get it correctly.
:For me, it'll give something like <code><nowiki>[[Special:Contributions/<<IP Address>>|<<IP Address>>]] <<Time>>, <<Date>>‎ (UTC)</nowiki></code>. For someone with a user account active, it'll be <code><nowiki>[[User:<<Username>>|<<Username>>]] ([[User talk:<<Username>>|talk]]) <<Time>>, <<Date>>‎ (UTC)</nowiki></code> ''unless'' you've messed with your personal profile settings.
:It doesn't matter much. Best to still have Time and Date. And some form of your Username-related links... But just FYI. [[Special:Contributions/172.70.162.171|172.70.162.171]] 19:44, 29 June 2023 (UTC)

Am I the only one who interpreted the glass being part of the edge of the table to mean that there is not actually a bottom to the glass? The tooltip text seems to suggest otherwise, but it is a humorous interpretation. [[Special:Contributions/172.71.26.42|172.71.26.42]] 19:35, 29 June 2023 (UTC)

;The tabletop is not glass

Just FYI, the tabletop itself is definitely not glass. That's why you can't see the rear legs through the surface of tabletop.

What makes this comic funnier is the very fact that they have attached a glass (as in glass of liquid) to the surface of a regular table on which the tabletop is not itself made of glass.

If the tabletop were made of glass, then the humour around 'glass-topped table' would be lessened, because it would be combining two different and therefore ambiguous senses of that phrase. {{unsigned|Lheydon|02:25, 30 June 2023}}

:Actually, it just looks more like a glass-topped table (a table with [https://www.egw.co.uk/products/6mm-rectangle-toughened-glass-rattan-table-topper a glass pane on top of its wooden/whatever surface]; acting to be more wipe-clean/protective, as well as aesthetic) than a table with a glass top (a glass pane as [https://www.dunelm.com/product/milan-oak-glass-top-coffee-table-1000108238 the entire surface span], held inside the legs-and-edges frame). That, or it ''is'' the latter but the angle of view and background makes the reflection off the surfaces overwhelmingly more dominant than the refracted view through both surfaces and towards(/from) the underside. [[Special:Contributions/172.70.91.53|172.70.91.53]] 03:46, 30 June 2023 (UTC)

:It most definitely '''''is''''' a glass table, or at least has glass as a top. The diagonal lines on it denote the shine off of the glass. We don't see the leg to help make it evident there IS a top, that the tabletop isn't missing entirely. :) [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 04:26, 2 July 2023 (UTC)

::True, I suppose that is also another possibility. [[Special:Contributions/162.158.2.191|162.158.2.191]] 04:25, 30 June 2023 (UTC)

The caption states "glass top", so the pun on "table covered with a sheet of glass" and "table with a drinking glass on top" is explicit. Any [https://en.wikipedia.org/wiki/Milk_glass non-transparent] glass would satisfy the first condition (as would the case of a glass insert atop a non-glass surface, mentioned above), and spare Randall the effort of trying to draw in that fourth table leg. [[Special:Contributions/172.69.33.154|172.69.33.154]] 06:28, 30 June 2023 (UTC)
:It's also clear (no pun intended... but I'll also happily claim it if nobody else wants it!) that we can see the thickness of the 'top' both at the front (where we're obliquely edge on) ''and'' at the rear (where we're seeing the internal 'edge-away'), indicating that it is certainly a transparent(-enough) pane of material of a number of millimetres thickness above whatever opaque material might lie immediately beneath. (And saving complexity of drawing not just thr upper rear bit of leg, but also the rear/second-side frame support and/or any attachment method that isn't just gravity+friction, or maybe adhesive, in action.) [[Special:Contributions/172.70.90.106|172.70.90.106]] 07:58, 30 June 2023 (UTC) - PS: I am a little worried, though, that (by sight alone) the upwards trajectory of the mostly hidden leg seems to ''not'' project up to hit the corner of the table as you'd expect. Not much visible length, so might actually be some wriggle-room available to end up where it ought to by assuming a slight amount of skew away from the apparent direction due purely to drawing vaguenesss or an optical illusion, but it does seem that little bit off.

:This earnest discussion of the [https://www.vocabulary.com/dictionary/draftsmanship draftsmanship] of this cartoon calls to mind a [https://www.arthur-conan-doyle.com/index.php/How_I_Write_My_Books statement] by no less an authority than Sir Arthur Conan Doyle: "... so long as you produce your dramatic effect, accuracy of detail matters little. I have never striven for it and have made some bad mistakes in consequence. What matter If I can hold my readers?" [[Special:Contributions/172.70.214.9|172.70.214.9]] 21:38, 30 June 2023 (UTC)

::It is as well that a gentleman holding that attitude towards "accuracy of detail" went into fiction writing and not his original intended career: [https://en.wikipedia.org/wiki/Arthur_Conan_Doyle#Medical_career medicine]. [[Special:Contributions/162.158.90.24|162.158.90.24]] 21:48, 30 June 2023 (UTC)
:::Sir Arthur was always {{w|File:Cottingley_Fairies,_page_463,_The_Strand_Magazine_-_1920_-_Vol.Jul-Dec.jpg|away with the fairies}}, anyway... [[Special:Contributions/162.158.34.20|162.158.34.20]] 22:45, 30 June 2023 (UTC)

All this discussion is rendered a bit moot by the fact that the text underneath the comic says that the glass is "built in to the glass top".[[Special:Contributions/172.70.162.62|172.70.162.62]] 09:18, 3 July 2023 (UTC)

1006: Sloppier Than Fiction

2023-06-29T00:52:00Z

172.70.162.62: /* Explanation */

{{comic
| number = 1006
| date = January 20, 2012
| title = Sloppier Than Fiction
| image = sloppier_than_fiction.png
| titletext = Roger Ebert once called you directionless and unwatchable.
}}

==Explanation==
In this strip, Goatee Guy claims that "if they made my life into a move, no one would believe it", suggesting that he thinks his experiences are so unlikely and interesting that they'd be considered too exaggerated for fiction.

Cueball agrees that no one would believe the movie, but claims that it's due to "the poorly written dialogue and unlikeable main character", turning the claim into a put-down of Goatee Guy. This response has two main aspects: that the events Goatee Guy is describing aren't especially well-told, and that Goatee Guy himself is personally unpleasant (in addition to not be especially articulate, or conveying a rambling anecdote as meaningful as he believes them to be).

From what little we hear of Goatee Guy's story, both of those assumptions seem to be justified. The crux of his story is that his ex-girlfriend had once dated an acquaintance of his, which is not a particularly uncommon or interesting event. Absent a more interesting twist (or at least some interesting storytelling), it constitutes a mild coincidence, not something particularly noteworthy, let along implausible.

And the little we know about Goatee Guy helps explain why Cueball finds him unlikeable. He did something that he claims "technically ''wasn't'' cheating", which implies that he was unfaithful, and tried to justify himself with a loophole. Then he went around telling the story to others, apparently blaming his ex, rather than himself, and repeats Brett characterizing her as "crazy". All of these things make him sound boorish, rude, self-centered, and misogynistic.

The title is a play on the old saying that "truth is stranger than fiction." In this case, the title implies that Goatee Guy's story isn't stranger than fiction, but is a sloppy enough story that it wouldn't qualify as good fiction.

In the title text, {{w|Roger Ebert}} was a famous American {{w|movie critic}}, who could be quite caustic when reviewing a movie he disliked. "Directionless" and "unwatchable," along with Cueball's initial complaints of "poorly-written dialogue and unlikeable main character," are common criticisms of bad movies, but have entirely different and much more personally cutting connotations when applied to a human being.

==Transcript==
:[A douchebag with a goatee and a bad haircut talks to Cueball while holding a drink.]
:Goatee Guy: Even though it technically ''wasn't'' cheating, she dumped me anyway! So I tell Bret, and he's like "She sounds just like ''my'' crazy ex." And I was like, "dude, what was her name?" and it was the ''same girl.''
:Goatee Guy: I swear, if they made my life into a movie, no one would believe it.
:Cueball: Yeah, though mostly because of the poorly-written dialogue and unlikeable main character.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Sex]]

117: Pong

2023-06-05T12:54:36Z

172.70.162.62: /* Explanation */ it's a joke goddammit

{{comic
| number = 117
| date = June 19, 2006
| title = Pong
| image = pong.png
| titletext = Following this, the pong paddle went on a mission to destroy Atari headquarters and, due to a mixup, found himself inside the game The Matrix Reloaded. Boy, was THAT ever hard to explain to him.
}}

== Explanation ==
This comic largely refers to the 1999 movie ''{{w|The Matrix}}'', which is about escaping a simulated reality. In the movie, a hacker called {{w|Neo (The Matrix)|Neo}} realizes that the world he lives in is fake, and that, like every other human, he is used as a slave battery by machines that, to keep them under control, make them feel like they're "living" in what is actually a computer-generated simulation of the world, called the "Matrix." Upon discovery, Neo rebels against this misuse of mankind and trains himself to interact with the computers that run the world until, being "the One" mentioned by a prophecy, he is able to control and use them to his own advantage. He takes part in a series of missions against those machines that wanted to keep the humans trapped in a simulated environment.

In {{w|Pong}}, one of the earliest video games, one can play virtual table tennis against the computer. A ball (the tiny block) is "hit" by a paddle (the long block) and crosses over the screen, to be "hit" again by the other paddle. Failure to return the ball results in a point won by the opponent. The speed of the ball increases as the rally runs longer.

The two game programmers in the first frame apply Neo's story to the {{w|Artificial intelligence|AI}} bots they create to serve as computer players in their video games: What if one of them learns enough to become sentient and understands the environment the programmers trapped it in? The outcome is shown: The paddle bot, understanding the game and realizing it is "the One," takes control of the code of Pong to make the ball stop and drop. The same thing happens in the movie, where Neo, by "seeing through the code," is able to stop bullets fired at him, and simply let them drop on the floor.

This is also possibly, though not likely, a pun on the meaning of the term "the One," as the long thin paddle looks very similar to how a numeral "1" could be written in several fonts.

In the title text, we learn that after increasing in intelligence, the "paddle" went on to destroy the headquarters of {{w|Atari}}, the producer of Pong, which "trapped" the paddle into the game, much like Neo sought to destroy the machines to free the humans. In the process, the paddle ended up inside the game ''{{w|Enter the Matrix}}'' (a video game produced with ''{{w|The Matrix Reloaded}}'', a sequel to ''The Matrix''), also published by Atari. Since the whole premise of The Matrix is that everyone is trapped in virtual reality, the paddle now found itself in a virtual virtual reality or essentially a meta-virtual reality, which could be pretty hard to comprehend.

==Transcript==
:Cueball: So what do we do if video game AI opponents become smart enough to question the "Matrix" into which we've put them?
:Pong paddle: Wait a minute! None of this is real! I can see through the world! I can see the code! I AM THE ONE!
:[The pong ball is moving towards the paddle.]
:[The pong ball slows down.]
:[The pong ball stops in midair.]
:[The pong ball drops towards the bottom of the screen.]
{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics with color]]
[[Category:Video games]]
[[Category:The Matrix]]
[[Category:Artificial Intelligence]]