explain xkcd - User contributions [en]

2481: 1991 and 2021

2026-04-24T01:54:43Z

2603:6011:1F0:2A40:DC22:1F47:2399:3124: /* Explanation */

{{comic
| number = 2481
| date = June 25, 2021
| title = 1991 and 2021
| image = 1991_and_2021.png
| titletext = "Oh, and our computers all have cameras now, which is nice during the pandemic lockdowns." "The WHAT."
}}

==Explanation==

This comic shows a Cueball from 2021 who is [[2280:_2010_and_2020|once again]] discussing the future's technology with White Hat, this time in 1991 instead of 2010. White Hat is awed by the advances in technology, but is not expecting that the law combating laser attacks on passenger aircraft is not the most important thing mentioned.

"Laser attacks on airliners" ''sounds'' dramatic and important, and White Hat probably thinks that {{w|laser weapon}}s have been developed and used to attack aircraft. Given that "a [US] federal law" has been passed to combat such attacks, White Hat may be envisioning a future where US citizens have access to laser guns, and some reckless individuals have been firing them at airplanes. (If it were some other group like terrorists or foreign militaries, a federal law would be unlikely to dissuade them.)

In reality, the "lasers" in question are low-powered {{What If|13|laser pointers}}, which some people aim at passenger airliners as a (dangerous) prank. When the beam hits the airplane, it cannot damage the plane itself, much less shoot it from the sky;{{citation needed}} it can, however, blind the pilot, which poses a threat to them and their passengers. A law ([https://www.law.cornell.edu/uscode/text/18/39A 18 USC §39A]) was thus passed in 2012 to criminalize this.

The robot fighting TV shows mentioned include ''{{w|BattleBots}}'', {{w|Robot Wars (TV series)|''Robot Wars''}} and {{w|MegaBots Inc.|''MegaBots''}}, the earliest of which started in 1998. In them, machines armed with a variety of weapons fight in an arena. These are not technically robots or drones in the traditional sense of operating autonomously; for the most part, they are either remote controlled, or are piloted by humans and have only rudimentary on-board computer systems. They are certainly not controlled by AI. Also, while these shows have been popular enough to return to the air after periods of hiatus, they are not nearly as popular as sports involving humans.

In this comic, "cordless phone" may be meant literally, meaning any wireless phone without a cord. That's distinct from common parlance where "cordless phone" is distinct from a cellular phone, and is a wireless extension of a landline (typically of limited range, i.e. within a home and perhaps its immediate outside area). It seems likely that Cueball was using a term he believed a 1991 citizen would more easily relate to. Although cell phones had been in use for over a decade by 1991, they were most commonly depicted as a foible of a stereotypical "businessman", typically accompanied by displays of distraction, classism and self-importance. The term "cell phone" was at that time frequently used to refer to older analog cellular networks, with many mobile users proud of their new CDMA or GSM "''digital''" phones, as distinct from true "cellular" systems which have been deprecated since that time (this distinction has since disappeared from common usage). A more general term used in modern parlance, such as "mobile phone" or "wireless phone" may have been less recognizable to the average person in 1991. Describing a cell phone as "a cordless phone [where you can] send news stories to your friends" would be a reasonable way of describing a cell phone to a person of that era.

Additionally, cellular phones today do not have much longer range than cellular phones of 1991 (in fact most have less range, due to their lower transmission power and use of higher frequencies, as well as indirectly due to increasing crowding on most wireless frequencies). Cordless phones reliant on a land-line may exhibit somewhat longer range than they did in 1991, due to improvements in digital error correction and audio compression. Although the effective range of a single transmission at a given power and frequency would otherwise be reduced by interference from the proliferation of other wireless devices outside functional range and/or operating independently. Satellite phones also offer more terrestrial range than cellular or cordless landline phones, however their functional range has not greatly increased since 1991 either (being already sufficient to reach a satellite within line-of-sight above). A possible explanation for a perceived "longer range" is that cellular phone towers are much more omnipresent than in 1991, granting cellular devices much greater functional area even though their functional range from ''one'' tower is typically less than in 1991.

Sharing on social media has distorted what news stories people encounter. Instead of a {{w|Propaganda model|curated}} selection of important{{Citation needed}} news [https://www.rollingstone.com/politics/politics-features/iraq-war-media-fail-matt-taibbi-812230/ fact-checked] by a {{w|Dewey_Defeats_Truman|newspaper}} or tv/{{w|Radio_Free_Europe/Radio_Liberty|radio}} broadcast from a [https://upload.wikimedia.org/wikipedia/commons/8/83/Corporationsownmedia.png large corporate media conglomerate], we see only what people similar to us found interesting.

By most reasonable measures, the most important technologies on the list could be seen as the rise of mobile phones and the ability to easily share news stories (aside of course, from any perceived advent of high-powered laser weapons or televised robotic warfare). The first of these, mobile phone usage (and smartphones in particular) has led to a dramatic change in how people communicate, with a large amount of communication now remote, which was not as convenient in the 1990s (requiring, for example, setting up {{w|roaming}} at the carrier's office before taking the phone to another city) and impossible for most people a few decades prior: Low frequency wireless for personal communication was relatively uncommon in the early '90s and remains so today. Sharing of news stories person-to-person is partly blamed for the spread of {{w|fake news}}; misinformation has become more and more politically, legally and socially significant in the past few years. While wireless communication has certainly had enormous and wide-ranging effects, the factuality of the data communicated is arguably of greater importance than the means of its communication. The joke is that the impact of a technology on society isn't really about how exciting or dangerous it might look at first glance.

The title text horrifies '90s White Hat, as it not only refers to a pandemic serious enough to induce lockdowns, but mentions it casually, in reference to the existence of computer webcams. [[:Category:COVID-19|COVID-19]] is already a hugely impactful deadly disease, but by mentioning it without details, it leaves White Hat to guess as to the details. Cueball doesn't specify whether there have been one or more pandemics (the plural use of 'lockdowns' could be taken to imply that there were more than one — of course there were, spread across both geography and time, but most people will have encountered one or more across the same pandemic, rather than multiple pandemics serious enough to each promote at least one lockdown), or how serious they were, how long-lasting or how many lives were lost to them. In consequence, White Hat could easily be assuming a dystopian future even worse than what really happened.

==Transcript==

:[Cueball (with an aura) is talking to White Hat.]
:White Hat: Welcome to 1991!
:White Hat: So you're from 2021? What happens with technology over the next 30 years?

:[Same scene, except Cueball has his palm out.]
:Cueball: We passed a federal law to combat laser attacks on airliners, and there are TV shows where robots battle.
:Cueball: Also, cordless phones are longer range now, and it's really easy to send news stories to your friends.
:White Hat: Wow, okay.

:[Same scene.]
:Cueball: Now, try to guess which of those things turn out to be important.
:White Hat: ...is it not the lasers?
:Cueball: It is not the lasers.

==Trivia==
On release, the title text was not actually included as such. It was instead included as the text of a "see also" link, which is often invisible to readers and is activated by clicking the comic. Such links have been used in the past for larger versions of the comic or for related information on other sites. Here, it linked back to the comic itself, and was evidently a mistake.

{{comic discussion}}

[[Category:Time travel]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring White Hat]]
[[Category:COVID-19]]

2478: Alien Visitors 2

2026-04-24T01:51:45Z

2603:6011:1F0:2A40:DC22:1F47:2399:3124: /* Explanation */

{{comic
| number = 2478
| date = June 18, 2021
| title = Alien Visitors 2
| image = alien_visitors_2.png
| titletext = "Although fresh juice DOES sound--" "NO! For humanity to survive we must learn from the mistakes of the past."
}}

==Explanation==
This comic follows the previous comic in the mini-series, [[2477: Alien Visitors]]. The aliens now return to show us even more "advanced" inventions. As with the previous strip, the only innovations they offer are not only things that humans know how to build, but things we figured out some time ago, and are now obsolete. As with the pyramids and Stonehenge, these inventions might have been impressive in their time but now offer nothing to humanity.

{{w|Biplane}}s are planes with two sets of wings, which provide more of the necessary lift at slow speed than a contemporaneous {{w|monoplane}}, but develop increased drag and aerodynamic and air-frame issues as higher airspeeds became possible/necessary. Biplanes have been obsolete for most purposes since the 1930s, though they remain in use for agriculture and aerial sports.

A {{w|blimp}} is a lighter than air aircraft with no internal structure. These aircraft were traditionally filled with hydrogen gas to provide the needed buoyancy, due to the lower density of hydrogen and a US monopoly on helium limiting availability for the German blimp manufacturer. Hydrogen is highly flammable and thus presents a safety issue: however, its use has gradually increased, considering that it is far cheaper than helium. The famous {{w|Hindenburg_disaster|''Hindenburg'' disaster}} is widely seen as a reason hydrogen airships are unlikely to be widely accepted. However, it is still disputed whether the hydrogen or the coating of the airframe caused the fire. Blimps are still used today, but only rarely, in niche applications, such as for advertising or for aerial photography/videography. Modern airships generally use helium as a lifting gas, which is more expensive, but non-flammable.

{{w|Tetraethyllead}} ((CH3 CH2)4Pb) is a chemical added to gasoline (mostly from the 1920s to the 1990s — although some countries [https://web.archive.org/web/20171115235249/http://wedocs.unep.org/bitstream/handle/20.500.11822/17542/MapWorldLead_March2017.pdf?sequence=1&isAllowed=y still use it to this day]) to prevent {{w|engine knocking}}. Lead is toxic and bio-accumulative, and there's substantial evidence that its use in gasoline caused widespread lead exposure, impacting public health on a huge scale. It was easily one of the deadliest inventions of the 20th century. The aliens seem surprised to learn of these toxic effects, and their concern implies that they may be using leaded gasoline themselves, but it's unclear whether they might think that their biology may by vulnerable to lead as well or whether they never considered that biologies alien to theirs would be.

The final invention appears to be a reference to {{w|Juicero}}, a defunct and short-lived brand of juicer, which has become iconic of the absurdity of modern technology investment. The company produced a high-tech, internet-connected juicer which sold for $700, and only worked on the company's proprietary branded single-serving bags of pulped fruit, which were available by subscription for $5-$7 per serving. The company raised over $100 million in startup capital, but quickly went out of business because most consumers considered the expensive product to be nearly useless, coupled with a rather damning [https://www.youtube.com/watch?v=5lutHF5HhVA video by Bloomberg] demonstrating said packets could easily be squeezed by hand. The title text singles this invention out, calling it one of the "mistakes of the past".

After the latest showing of unimpressive "inventions", the humans start questioning how "advanced" the aliens really are. It's traditionally assumed that a species capable of interstellar travel would have a host of other advanced technologies, which is inconsistent with the unimpressive and not only obsolete, but also fatally flawed inventions they're offering to humanity. The humans on the ground ask whether they actually built their own flying saucer. They also consider the wisdom of standing directly under the saucer, implying that, if the aliens did build it, it's likely to be unreliable, and may be at risk of crashing (though perhaps a bit ironically, most of the obsolete inventions were nonetheless reliable: biplanes and Tetraethyllead both work as advertised despite their downsides, and the Juicero was commonly slammed for being needlessly over-engineered).

==Transcript==
:[A flying saucer is flying high above Ponytail who is walking towards White Hat, Cueball and Megan. Those three are looking up at the spacecraft. The humans are drawn very small standing on the ground beneath it. The aliens inside speak to them from inside their saucer, indicated with zigzag lines between it and the text.]
:Aliens: Greetings, humans. We have returned.
:Aliens: Since you already have pyramids, we've brought you more advanced wonders.

:[Pan up to only showing the flying saucer which has two beams below it, the left showing an outline of a biplane and the right is showing an outline of a blimp. The humans reply off-panel. Given their positions before, the first is probably Ponytail, but it cannot be determined.]
:Aliens: These machines will let you conquer the sky!
:Voice 1 (off-panel): A biplane?
:Voice 1 (off-panel): Aren't monoplanes more efficient?
:Voice 2 (off-panel): Does that blimp use hydrogen?

:[Zoom in on the four humans looking up, the Aliens reply from above the panel. There is a chemical formula in an outline from the alien flying saucer, shown in a similar manner to the other items.]
:Chemical formula: (CH3 CH2)4 Pb
:Aliens (off-panel): Add this elixir of lead to your gasoline and your engines will run smooth.
:White Hat: Lead? Isn't that stuff toxic?
:Aliens: Is it?
:Aliens: Oh no.

:[Zoom back out, as in first panel but the flying saucer and the humans are shown in silhouette. A beam from the saucer is showing an outline of a juice machine.]
:Aliens: Okay, uh.
:Aliens: This device's electric press can squeeze fresh fruit juice from bags of pulp!
:Ponytail: ...Just curious, did you build that saucer?
:Cueball: Maybe we shouldn't stand right under it.

{{comic discussion}}

[[Category:Comics sharing name|Alien Visitors 2]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Aliens]]
[[Category:Airships]]
[[Category:Alien Visitors]]

3229: Grammar

2026-04-22T23:33:10Z

2603:6011:1F0:2A40:DC22:1F47:2399:3124:

{{comic
| number = 3229
| date = April 6, 2026
| title = Grammar
| image = grammar_2x.png
| imagesize = 227x312px
| noexpand = true
| titletext = Communication is one of the most popular ways to transmit information, ahead of rivals such as
}}

==Explanation==
{{incomplete|Explanation of the second method should focus on language structure rather than communication.}}

[[Miss Lenhart]] is shown teaching a classroom about {{w|grammar}}, which is a system of rules describing how a certain language is structured. This is useful to make communication and meaning standardized and clear, with little to no difficulty in parsing. However, due to having many rules and structures to learn, the grammar of some languages can be viewed with annoyance by some people who wish it were 'simpler'. Miss Lenhart claims that grammar is "''one'' of the most popular ways to structure a language" and presents two alternative methods, but this is odd, as grammar ''is'' how we structure a language. Also, if the names of these 'rivals' illustrate their use, they reflect their own rules, and thus imply their own grammar. She also presents two alternative methods (though it could be interpreted as a list of four items without commas to split it up) that competed to substitute grammar, yet evidently never took off to be implemented for practical use. Despite seeming nonsensical, they've gained their own linguistic terminology:

;Words order words random words words random good
:This alternate to grammar likely has very loose rules around structure, as it consists of simply stating words that relate directly to the idea being conveyed (as opposed to normal grammar, which focuses on linking together many words to form a single coherent idea). This is superficially similar to some languages, like Ukrainian, where word order does not matter. However, in these languages, its role in the sentence is simply replaced with more in-depth conjugation, which is also a form of grammar. The provided sentence, conversely, appears to have neither conjugation nor any meaningful ordering, which would make it difficult to convey more complex concepts.

;EEEEEEEEEEEEEEEEEEE
:This proposes a very narrow method of structuring language consisting of only the capital letter "E". It could be argued that this method of structuring language is able to form a coherent idea, but the number of distinct ideas that may be formed using this method is only one, being a string of "E"s, which may represent an attempt to draw another's attention, unless the precise number of "E"s represents a raw {{w|Unary numeral system|value}} which can be indexed to distinct messages. Messages could also be encoded by fluctuation of the volume or pitch of the scream. A different scream-based method of communication was mentioned in [[3054: Scream Cipher]]. It has also been postulated that more complex ideas may be transferred through the use of encoding patterns such as Morse code or with other vowels. One of the questions recorded in [[Randall]]'s ''[[What If? 2]]'', in the {{what if|2-58.5|Short Answers #5 chapter}}. The "question", posted by Nate Yu, was a string of 960 letter "E"s, to which Randall replied: "I feel you, Nate".

;Communication is one of the most popular ways to transmit information, ahead of rivals such as
:The title text continues Lenhart's lecture, as she moves on to {{w|communication}} and its rival alternatives, similar to the subject of grammar, but seems to cut off before naming the first one. Lenhart is self-demonstrating non-communication, as the sudden stop in the middle of the sentence could be a joke for how there are no other ways to convey information without communication, since communication is literally the act of conveying information. Still, this doesn't rule out at least one other 'rival' to communication, as Lenhart implies that at least one more method exists. If communication is defined as successful transmission of information, it is possible she is referring to some sort of method(s) that attempts, but fails to transmit information. Nonetheless, demonstrating lack of communication would not be useful in this setting without further explanation, as abruptly ceasing to provide more information could cause confusion in her students.

==Transcript==
:[Miss Lenhart is teaching in a classroom. Two students can be seen sitting at desks in front of her, Cueball in the first row and Megan in the second row.]
:Miss Lenhart: '''Grammar''' is one of the most popular ways to structure a language, ahead of rival methods such as '''''words order words random words words random good''''' and '''''EEEEEEEEEEEEEEEEEEE'''''.

{{comic discussion}}<noinclude>

[[Category:Comics featuring Miss Lenhart]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Language]]

3236: Border Message

2026-04-22T23:29:43Z

2603:6011:1F0:2A40:DC22:1F47:2399:3124: /* Explanation */

{{comic
| number = 3236
| date = April 22, 2026
| title = Border Message
| image = border_message_2x.png
| imagesize = 736x316px
| noexpand = true
| titletext = Thanks to differences in logging regulations, the messages actually turned out to be visible from the air.
}}

==Explanation==
{{incomplete|This page was created by a bored legislator. Don't remove this notice too soon.}}

In this comic, legislators who were negotiating the boundary between two geographic areas ("Southlake" and "East Valley", likely counties or cities) livened up the normally boring process by arranging for the boundary to spell out a message when viewed on a map. It's unknown whether the areas are municipal regions, counties, etc. The boundary definition {{w|Enclave and exclave|includes}} multiple areas — such as the bottom of the W, the interior of the O's and other letters with "holes", the apostrophe and so on — that are exclaves (probably of the northern territory, that are surrounded by the southern one, in most cases) or else may be (unlabeled) enclaved territories in their own right that are associated with no other disconnected area. This would be very inconvenient for the tourists and locals who have the map, since they would have to constantly consult the map to see whether they are in East valley or Southlake.

The title text implies that the area around the border is forested. Due to the different logging regulations in the two areas, the densities or types of trees on each side of the border are so different that you can see the border, and hence the messages, when looking down on the land.

This comic may have been inspired by {{w|gerrymandering}}: defining voting districts to favor a particular group. This often results in districts with very unusual shapes. The comic was published on the day after Virginia voters passed {{w|2026 Virginia redistricting amendment|a referendum approving redistricting}} that favored the Democratic Party. See also the {{w|Belgium-Netherlands border}}, which is extremely chaotic. This comic also happens to have been published on earth day.

==Transcript==
{{incomplete transcript|Don't remove this notice too soon.}}

[A section of a map showing the border between the geographic areas East Valley and Southlake. The border is shown as a dotted line, and it spells out a message:]

WE HOPE YOU'RE ENJOYING THIS MAP

[Caption below comic:]

When local legislators get bored

{{comic discussion}}<noinclude>