https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=172.69.33.223&feedformat=atomexplain xkcd - User contributions [en]2024-03-28T12:36:57ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=2697:_Y2K_and_2038&diff=2986002697: Y2K and 20382022-11-11T22:44:50Z<p>172.69.33.223: /* Explanation */ word choice</p>
<hr />
<div>{{comic<br />
| number = 2697<br />
| date = November 11, 2022<br />
| title = Y2K and 2038<br />
| image = y2k_and_2038_2x.png<br />
| imagesize = 527x190px<br />
| noexpand = true<br />
| titletext = It's taken me 20 years, but I've finally finished rebuilding all my software to use 33-bit signed ints.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a Y2K-BRICKED BOT (MADE JAN 1, 1970). Do NOT delete this tag too soon.}}<br />
<br />
[[File:Year 2038 problem.gif|thumb|An animation of the 2038 bug in action. The {{w|integer overflow}} error occurs at 03:14:08 UTC on 19 January 2038.]]<br />
<br />
The Y2K bug, or more formally, the {{w|year 2000 problem}}, was the computer errors caused by two digit software representations of calendar years incorrectly handling the year 2000, such as by treating it as 1900 or 19100. The {{w|year 2038 problem}} is a similar issue with timestamps in {{w|Unix time}} format, which will overflow their {{w|Signed number representations|signed}} 32-bit binary representation on January 19, 2038.<br />
<br />
While initial estimates were that the Y2K problem would require about half a trillion dollars to address, there was widespread recognition of its potential severity several years in advance. Concerted efforts among organizations including computer and software manufacturers and their corporate and government users reflected unprecedented cooperation, testing, and enhancement of affected systems costing substantially less than the early estimates. A major problem had struck IBM mainframes on and after August 16, 1972 (9999 days before January 1, 2000) that caused magnetic tapes that were supposed to be marked "keep forever" instead be marked "may be recycled now." But on New Year's Day 2000, few major errors actually occurred. Those that did usually did not disrupt essential processes or cause serious problems, and the few of them that did were usually addressed in days to weeks. The software code reviews involved allowed correcting other errors and providing various enhancements which often made up at least in part for the the cost of correcting the date bug.<br />
<br />
It is unclear whether the 2038 problem will be addressed as effectively in time, but documented experience with the Y2K bug and increased software modularity and access to source code has allowed many otherwise vulnerable systems to already upgrade to wider timestamp and date formats, so there is reason to believe that it may be even less consequential and expensive. The 2038 problem has been previously mentioned in [[607: 2038]] and [[887: Future Timeline]].<br />
<br />
The caption in this comic provides a punchline: everyone should have completed their "Y2K recovery" as it has been a full 22 years since the year 2000. It is highly unlikely that there are more than a very few consequential older systems that still suffer from this bug, and systems built since already handle years after 1999 correctly.<br />
<br />
The title text refers to replacing the 32-bit signed Unix time format with a hypothetical new 33-bit signed {{w|Integer (computer science)|integer}} time and date format, which is very unlikely as almost all contemporary computer data structure formats are allocated no more finely than in 8-bit bytes. Taking 20 years to develop and implement such a format is not entirely counterproductive, as it would add another 68 years of capability, but it is far more counterproductive than upgrading to the widely available and supported 64-bit Unix time replacement format and software compatibility libraries.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
[A timeline rectangle with 37 short diviiding lines betweem the two ends, defining it into 38 minor sections, with the label "2000" above, associated with the leftmost edge, "2038" associated with the rightmost edge and "2019" directly over the centremost division that starts the section which covers that year, which is also extended to form a dotted line divided the whole height of the timeline into two equal 19-section halves. The left half has the label "Recovering from the Y2K bug" and the right half is labeled "Preparing for the 2038 bug". A triangular arrowhead labeled "Now" is also above indicating a rough position most of the way through the section that would represent the year 2022.]<br />
<br />
[Caption:] Reminder: By now you should have finished your Y2K recovery and be several years into 2038 preparation<br />
<br />
{{comic discussion}}<br />
[[Category:Calendar]]<br />
[[Category:Computers]]<br />
[[Category:Programming]]<br />
[[Category:Timelines]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2654:_Chemtrails&diff=2920052654: Chemtrails2022-08-04T12:04:22Z<p>172.69.33.223: /* Explanation */ this is a legitimate explanatory fact</p>
<hr />
<div>{{comic<br />
| number = 2654<br />
| date = August 3, 2022<br />
| title = Chemtrails<br />
| image = chemtrails.png<br />
| titletext = Ants have reverse chemtrails--regular citizens spraying chemicals everywhere they go to control the government.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by an INKJET PRINTER FILLED WITH PERFUME. Do NOT delete this tag too soon.}}<br />
<br />
{{w|Ant}}s, studied along with other insects by {{w|entomologist}}s, leave trails of signalling secretions such as {{w|pheromones}}, natural chemicals that they emit along the trail to and from food sources and other events. These chemical trails guide other ants in the colony to return to food, but are only informally refered to as chemtrails by biologists. <br />
<br />
[[Cueball]] is intentionally conflating these with {{w|chemtrails}}, the subject of a conspiracy theory that the government controls the population by spraying toxic or mind-/body-transformative chemicals from high-flying aircraft. This myth may be partly based on the practice of {{w|cloud seeding}}, which uses chemical flares containing silver nitrate to attempt to increase precipitation,[https://www.vox.com/videos/23290459/cloud-seeding-manmade-rain-future-perfect] on studies of chemical mind control among ants,[https://www.sciencedirect.com/science/article/abs/pii/S0022191016301640] or both. Despite [[1677: Contrails|occasional conflation]], this is unrelated to "contrails," short for "condensation trails," which are cloud-like lines in the sky created by jet engines. Such linear cloud-formations only sometimes arise from temperature and pressure disturbances of the passing engines rather than any deliberate release, but are highly visible in the right conditions under flightpaths, and may have the appearance of some active "spraying" action.<br />
<br />
Chemical manipulation of unwitting people is not uncommon, as general mood-enhancing effects in specific locations,[https://www.businessnewsdaily.com/3469-smells-shoppers-spend-more.html] and doesn't involve high-altitude airplanes. There is very little evidence that sophisticated mind control posited by chemtrail conspiracists is possible, even after extensive research.[https://www.google.com/books/edition/Poisoner_in_Chief/U6iDDwAAQBAJ]<br />
<br />
[[Ponytail]] specifically studies chemically-mediated cooperative ant navigation. [[Cueball]] knows she will be annoyed when he tells her, "So, I hear you're really into chemtrails?" Indeed, he gets the reaction he hoped for when she objects strongly and rejects this with a loud, "'''No!!'''" Terminology is often a sore spot for those who study "slave-making" socially parasitic species.[https://evolve.community.uaf.edu/2015/04/23/emantcipation-when-captured-ants-rise-against-their-captors/] [[Randall]] writes in the caption that this is how to annoy people like Ponytail.<br />
<br />
The title text contrasts individual ants instinctively deciding how the whole colony behaves by using chemicals to indicate routes to food or dangers to motivate the colony to react to their individual experiences, with the human fear of loss of personal independence by being regulated by otherwise disconnected ruling elites. <br />
<br />
Ants are a recurring theme, as are those who study them. See for instance [[1610: Fire Ants]]. Chemtrails was also the subject of [[966: Jet Fuel]], [[1677: Contrails]], and were mentioned in [[1803: Location Reviews]]. This comic has a similar format to [[2036: Edgelord]]: a simple one-panel interaction consisting of a (likely deliberate) misuse of a term in regards to a professional's work, followed immediately by the professional's upset outburst, and Randall's caption spelling out "How to annoy" the professional. Both of these seems to be related to Randall's [[:Category:My Hobby|hobbies]], as this is something he seems to think about a lot — how to annoy specific groups of people, which is necessary information for minimizing overall annoyance production.{{cn}}<br />
<br />
===Speculation===<br />
<br />
Ponytail may conceivably be a professional entomologist who once worked with an editor who inserted the word "chemtrails" in one of her [https://link.springer.com/article/10.1007/s00359-019-01363-z comparative physiology] or [https://link.springer.com/article/10.1007/s10071-020-01354-7 ''Animal Cognition''] drafts competing before a peer review panel with papers by [https://bio.kuleuven.be/ento/pdfs/billen_procnev_2006_signal_variety.pdf Johan Bilen] of the Leuven University Zoological Institute and Harvard's [https://www.hup.harvard.edu/catalog.php?isbn=9780674045880 Rüdiger Wehner].<br />
<br />
Chemical signalling for mind control is depicted in the ant-technology interaction speculative fiction-themed rock music video by the band ''Placebo'' entitled [https://www.youtube.com/watch?v=fISvc-yUU1A "Infrared."]<br />
<br />
Whether ant gland secretion signalling is {{w|Turing completeness|Turing-equivalent}} was explored in Douglas Hofstadter's ''{{w|Gödel, Escher, Bach|Gödel, Escher, Bach: an Eternal Golden Braid}}''.<br />
<br />
==Transcript==<br />
:[Cueball stands talking to Ponytail, who has her arms raised and has small lines above her head to indicate annoyance.]<br />
:Cueball: So, I hear you're really into chemtrails?<br />
:Ponytail: '''''No!!'''''<br />
<br />
:[Caption below the panel:]<br />
:How to annoy entomologists who study ant navigation<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Ponytail]]<br />
[[Category:Animals]]<br />
[[Category:Biology]]<br />
[[Category:Puns]]<br />
[[Category:Conspiracy theory]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2654:_Chemtrails&diff=2920042654: Chemtrails2022-08-04T12:01:26Z<p>172.69.33.223: /* Explanation */ alternative way to say the same thing?</p>
<hr />
<div>{{comic<br />
| number = 2654<br />
| date = August 3, 2022<br />
| title = Chemtrails<br />
| image = chemtrails.png<br />
| titletext = Ants have reverse chemtrails--regular citizens spraying chemicals everywhere they go to control the government.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by an INKJET PRINTER FILLED WITH PERFUME. Do NOT delete this tag too soon.}}<br />
<br />
{{w|Ant}}s, studied along with other insects by {{w|entomologist}}s, leave trails of signalling secretions such as {{w|pheromones}}, natural chemicals that they emit along the trail to and from food sources and other events. These chemical trails guide other ants in the colony to return to food, but are only informally refered to as chemtrails by biologists. <br />
<br />
[[Cueball]] is intentionally conflating these with {{w|chemtrails}}, the subject of a conspiracy theory that the government controls the population by spraying toxic or mind-/body-transformative chemicals from high-flying aircraft. This myth may be partly based on the practice of {{w|cloud seeding}}, which uses chemical flares containing silver nitrate to attempt to increase precipitation,[https://www.vox.com/videos/23290459/cloud-seeding-manmade-rain-future-perfect] on studies of chemical mind control among ants,[https://www.sciencedirect.com/science/article/abs/pii/S0022191016301640] or both. Despite [[1677: Contrails|occasional conflation]], this is unrelated to "contrails," short for "condensation trails," which are cloud-like lines in the sky created by jet engines. Such linear cloud-formations only sometimes arise from temperature and pressure disturbances of the passing engines rather than any deliberate release, but are highly visible in the right conditions under flightpaths, and may have the appearance of some active "spraying" action.<br />
<br />
Chemical manipulation of unwitting people is not uncommon, as general mood-enhancing effects in specific locations,[https://www.businessnewsdaily.com/3469-smells-shoppers-spend-more.html] and doesn't involve high-altitude airplanes. There is very little evidence that sophisticated mind control posited by chemtrail conspiracists is possible, even after extensive research.[https://www.google.com/books/edition/Poisoner_in_Chief/U6iDDwAAQBAJ]<br />
<br />
[[Ponytail]] specifically studies chemically-mediated cooperative ant navigation. [[Cueball]] knows she will be annoyed when he tells her, "So, I hear you're really into chemtrails?" Indeed, he gets the reaction he hoped for when she objects strongly and rejects this with a loud, "'''No!!'''" [[Randall]] writes in the caption that this is how to annoy people like Ponytail.<br />
<br />
The title text contrasts individual ants instinctively deciding how the whole colony behaves by using chemicals to indicate routes to food or dangers to motivate the colony to react to their individual experiences, with the human fear of loss of personal independence by being regulated by otherwise disconnected ruling elites. <br />
<br />
Ants are a recurring theme, as are those who study them. See for instance [[1610: Fire Ants]]. Chemtrails was also the subject of [[966: Jet Fuel]], [[1677: Contrails]], and were mentioned in [[1803: Location Reviews]]. This comic has a similar format to [[2036: Edgelord]]: a simple one-panel interaction consisting of a (likely deliberate) misuse of a term in regards to a professional's work, followed immediately by the professional's upset outburst, and Randall's caption spelling out "How to annoy" the professional. Both of these seems to be related to Randall's [[:Category:My Hobby|hobbies]], as this is something he seems to think about a lot — how to annoy specific groups of people, which is necessary information for minimizing overall annoyance production.{{cn}}<br />
<br />
===Speculation===<br />
<br />
Ponytail may conceivably be a professional entomologist who once worked with an editor who inserted the word "chemtrails" in one of her [https://link.springer.com/article/10.1007/s00359-019-01363-z comparative physiology] or [https://link.springer.com/article/10.1007/s10071-020-01354-7 ''Animal Cognition''] drafts competing before a peer review panel with papers by [https://bio.kuleuven.be/ento/pdfs/billen_procnev_2006_signal_variety.pdf Johan Bilen] of the Leuven University Zoological Institute and Harvard's [https://www.hup.harvard.edu/catalog.php?isbn=9780674045880 Rüdiger Wehner]. Terminology is often a sore spot for those who study "slave-making" socially parasitic species.[https://evolve.community.uaf.edu/2015/04/23/emantcipation-when-captured-ants-rise-against-their-captors/]<br />
<br />
Chemical signalling for mind control is depicted in the ant-technology interaction speculative fiction-themed rock music video by the band ''Placebo'' entitled [https://www.youtube.com/watch?v=fISvc-yUU1A "Infrared."]<br />
<br />
Whether ant gland secretion signalling is {{w|Turing completeness|Turing-equivalent}} was explored in Douglas Hofstadter's ''{{w|Gödel, Escher, Bach|Gödel, Escher, Bach: an Eternal Golden Braid}}''.<br />
<br />
==Transcript==<br />
:[Cueball stands talking to Ponytail, who has her arms raised and has small lines above her head to indicate annoyance.]<br />
:Cueball: So, I hear you're really into chemtrails?<br />
:Ponytail: '''''No!!'''''<br />
<br />
:[Caption below the panel:]<br />
:How to annoy entomologists who study ant navigation<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Ponytail]]<br />
[[Category:Animals]]<br />
[[Category:Biology]]<br />
[[Category:Puns]]<br />
[[Category:Conspiracy theory]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2654:_Chemtrails&diff=2919922654: Chemtrails2022-08-04T11:42:04Z<p>172.69.33.223: /* Explanation */ typographical convention</p>
<hr />
<div>{{comic<br />
| number = 2654<br />
| date = August 3, 2022<br />
| title = Chemtrails<br />
| image = chemtrails.png<br />
| titletext = Ants have reverse chemtrails--regular citizens spraying chemicals everywhere they go to control the government.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by an INKJET PRINTER FILLED WITH PERFUME. Do NOT delete this tag too soon.}}<br />
<br />
{{w|Ant}}s, studied along with other insects by {{w|entomologist}}s, leave trails of signalling secretions such as {{w|pheromones}}, natural chemicals that they emit along the trail to and from food sources and other events. These chemical trails guide other ants in the colony to return to food, but are only informally refered to as chemtrails by biologists. <br />
<br />
[[Cueball]] is intentionally conflating these with {{w|chemtrails}}, the subject of a conspiracy theory that the government controls the population by spraying toxic or mind-/body-transformative chemicals from high-flying aircraft. This myth may be partly based on the practice of {{w|cloud seeding}}, which uses chemical flares containing silver nitrate to attempt to increase precipitation,[https://www.vox.com/videos/23290459/cloud-seeding-manmade-rain-future-perfect] on studies of chemical mind control among ants,[https://www.sciencedirect.com/science/article/abs/pii/S0022191016301640] or both. Despite [[1677: Contrails|occasional conflation]], this is unrelated to "contrails", short for "condensation trails", which are cloud-like lines in the sky created by jet engines. Such linear cloud-formations arise from temperature and pressure disturbances of the passing engines rather than any deliberate release, but are highly visible in the right conditions to those who live under flightpaths, and may have the appearance of some active "spraying" action.<br />
<br />
Chemical manipulation of unwitting people is not uncommon, but is morena general mood-enhancing effect that works within a specific location[https://www.businessnewsdaily.com/3469-smells-shoppers-spend-more.html] and doesn't involve high-altitude airplanes. There is very little evidence that sophisticated mind control posited by chemtrail conspiracists is possible, even after extensive research.[https://www.google.com/books/edition/Poisoner_in_Chief/U6iDDwAAQBAJ]<br />
<br />
[[Ponytail]] specifically studies chemically-mediated cooperative ant navigation. [[Cueball]] knows she will be annoyed when he tells her, "So, I hear you're really into chemtrails?" Indeed, he gets the reaction he hoped for when she objects strongly and rejects this with a loud, "'''No!!'''" [[Randall]] writes in the caption that this is how to annoy people like Ponytail.<br />
<br />
The title text contrasts individual ants instinctively deciding how the whole colony behaves by using chemicals to indicate routes to food or dangers to motivate the colony to react to their individual experiences, with the human fear of loss of personal independence by being regulated by otherwise disconnected ruling elites. <br />
<br />
Ants are a recurring theme, as are those who study them. See for instance [[1610: Fire Ants]]. Chemtrails was also the subject of [[966: Jet Fuel]], [[1677: Contrails]], and were mentioned in [[1803: Location Reviews]]. This comic has a similar format to [[2036: Edgelord]]: a simple one-panel interaction consisting of a (likely deliberate) misuse of a term in regards to a professional's work, followed immediately by the professional's upset outburst, and Randall's caption spelling out "How to annoy" the professional. Both of these seems to be related to Randall's [[:Category:My Hobby|hobbies]], as this is something he seems to think about a lot — how to annoy specific groups of people, which is necessary information for minimizing overall annoyance production.{{cn}}<br />
<br />
==Transcript==<br />
:[Cueball stands talking to Ponytail, who has her arms raised and has small lines above her head to indicate annoyance.]<br />
:Cueball: So, I hear you're really into chemtrails?<br />
:Ponytail: '''''No!!'''''<br />
<br />
:[Caption below the panel:]<br />
:How to annoy entomologists who study ant navigation<br />
<br />
==Speculation==<br />
<br />
Ponytail may conceivably be a professional entomologist who once worked with an editor who inserted the word "chemtrails" in one of her [https://link.springer.com/article/10.1007/s00359-019-01363-z comparative physiology] or [https://link.springer.com/article/10.1007/s10071-020-01354-7 ''Animal Cognition''] drafts competing before a peer review panel with papers by [https://bio.kuleuven.be/ento/pdfs/billen_procnev_2006_signal_variety.pdf Johan Bilen] of the Leuven University Zoological Institute and Harvard's [https://www.hup.harvard.edu/catalog.php?isbn=9780674045880 Rüdiger Wehner]. Terminology is often a sore spot for those who study "slave-making" socially parasitic species.[https://evolve.community.uaf.edu/2015/04/23/emantcipation-when-captured-ants-rise-against-their-captors/]<br />
<br />
Chemical signalling for mind control is depicted in the ant-technology interaction speculative fiction-themed rock music video by the band ''Placebo'' entitled [https://www.youtube.com/watch?v=fISvc-yUU1A "Infrared."]<br />
<br />
Whether ant-gland secretion signalling is {{w|Turing completeness|Turing-equivalent}} was explored in Douglas Hofstadter's ''{{w|Gödel, Escher, Bach|Gödel, Escher, Bach: an Eternal Golden Braid}}''.<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Ponytail]]<br />
[[Category:Animals]]<br />
[[Category:Biology]]<br />
[[Category:Puns]]<br />
[[Category:Conspiracy theory]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2654:_Chemtrails&diff=2919912654: Chemtrails2022-08-04T11:40:34Z<p>172.69.33.223: /* Trivia */ Speculation</p>
<hr />
<div>{{comic<br />
| number = 2654<br />
| date = August 3, 2022<br />
| title = Chemtrails<br />
| image = chemtrails.png<br />
| titletext = Ants have reverse chemtrails--regular citizens spraying chemicals everywhere they go to control the government.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by an INKJET PRINTER FILLED WITH PERFUME. Do NOT delete this tag too soon.}}<br />
<br />
{{w|Ant}}s, studied along with other insects by {{w|entomologist}}s, leave trails of signalling secretions such as {{w|pheromones}}, natural chemicals that they emit along the trail to and from food sources and other events. These chemical trails guide other ants in the colony to return to food, but are only informally refered to as chemtrails by biologists. <br />
<br />
[[Cueball]] is intentionally conflating these with {{w|chemtrails}}, the subject of a conspiracy theory that the government controls the population by spraying toxic or mind-/body-transformative chemicals from high-flying aircraft. This myth may be partly based on the practice of {{w|cloud seeding}}, which uses chemical flares containing silver nitrate to attempt to increase precipitation,[https://www.vox.com/videos/23290459/cloud-seeding-manmade-rain-future-perfect] on studies of chemical mind control among ants,[https://www.sciencedirect.com/science/article/abs/pii/S0022191016301640] or both. Despite [[1677: Contrails|occasional conflation]], this is unrelated to "contrails", short for "condensation trails", which are cloud-like lines in the sky created by jet engines. Such linear cloud-formations arise from temperature and pressure disturbances of the passing engines rather than any deliberate release, but are highly visible in the right conditions to those who live under flightpaths, and may have the appearance of some active "spraying" action.<br />
<br />
Chemical manipulation of unwitting people is not uncommon, but is morena general mood-enhancing effect that works within a specific location[https://www.businessnewsdaily.com/3469-smells-shoppers-spend-more.html] and doesn't involve high-altitude airplanes. There is very little evidence that sophisticated mind control posited by chemtrail conspiracists is possible, even after extensive research.[https://www.google.com/books/edition/Poisoner_in_Chief/U6iDDwAAQBAJ]<br />
<br />
[[Ponytail]] specifically studies chemically-mediated cooperative ant navigation. [[Cueball]] knows she will be annoyed when he tells her, "So, I hear you're really into chemtrails?" Indeed, he gets the reaction he hoped for when she objects strongly and rejects this with a loud, "'''No!!'''". [[Randall]] writes in the caption that this is how to annoy people like Ponytail.<br />
<br />
The title text contrasts individual ants instinctively deciding how the whole colony behaves by using chemicals to indicate routes to food or dangers to motivate the colony to react to their individual experiences, with the human fear of loss of personal independence by being regulated by otherwise disconnected ruling elites. <br />
<br />
Ants are a recurring theme, as are those who study them. See for instance [[1610: Fire Ants]]. Chemtrails was also the subject of [[966: Jet Fuel]], [[1677: Contrails]], and were mentioned in [[1803: Location Reviews]]. This comic has a similar format to [[2036: Edgelord]]: a simple one-panel interaction consisting of a (likely deliberate) misuse of a term in regards to a professional's work, followed immediately by the professional's upset outburst, and Randall's caption spelling out "How to annoy" the professional. Both of these seems to be related to Randall's [[:Category:My Hobby|hobbies]], as this is something he seems to think about a lot — how to annoy specific groups of people, which is necessary information for minimizing overall annoyance production.{{cn}}<br />
<br />
==Transcript==<br />
:[Cueball stands talking to Ponytail, who has her arms raised and has small lines above her head to indicate annoyance.]<br />
:Cueball: So, I hear you're really into chemtrails?<br />
:Ponytail: '''''No!!'''''<br />
<br />
:[Caption below the panel:]<br />
:How to annoy entomologists who study ant navigation<br />
<br />
==Speculation==<br />
<br />
Ponytail may conceivably be a professional entomologist who once worked with an editor who inserted the word "chemtrails" in one of her [https://link.springer.com/article/10.1007/s00359-019-01363-z comparative physiology] or [https://link.springer.com/article/10.1007/s10071-020-01354-7 ''Animal Cognition''] drafts competing before a peer review panel with papers by [https://bio.kuleuven.be/ento/pdfs/billen_procnev_2006_signal_variety.pdf Johan Bilen] of the Leuven University Zoological Institute and Harvard's [https://www.hup.harvard.edu/catalog.php?isbn=9780674045880 Rüdiger Wehner]. Terminology is often a sore spot for those who study "slave-making" socially parasitic species.[https://evolve.community.uaf.edu/2015/04/23/emantcipation-when-captured-ants-rise-against-their-captors/]<br />
<br />
Chemical signalling for mind control is depicted in the ant-technology interaction speculative fiction-themed rock music video by the band ''Placebo'' entitled [https://www.youtube.com/watch?v=fISvc-yUU1A "Infrared."]<br />
<br />
Whether ant-gland secretion signalling is {{w|Turing completeness|Turing-equivalent}} was explored in Douglas Hofstadter's ''{{w|Gödel, Escher, Bach|Gödel, Escher, Bach: an Eternal Golden Braid}}''.<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Ponytail]]<br />
[[Category:Animals]]<br />
[[Category:Biology]]<br />
[[Category:Puns]]<br />
[[Category:Conspiracy theory]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=Talk:2654:_Chemtrails&diff=291988Talk:2654: Chemtrails2022-08-04T11:37:10Z<p>172.69.33.223: Respond to edits</p>
<hr />
<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
Ants navigate by following trails of chemicals on the ground, so it is ''technically'' a correct description, but also lumps ant navigation entomologists with conspiracy nuts.--[[User:NyanSequitur|NyanSequitur]] ([[User talk:NyanSequitur|talk]]) 16:01, 3 August 2022 (UTC)<br />
:The point is that scientists don't call these trails "chemtrails". Cueball has made that mistaken link. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 16:05, 3 August 2022 (UTC)<br />
I must say that the title-text made me laugh out loud the most. (Also, though I'm sure there's no direct or even impliable link, made me fondly recall Aunt Hillary in {{w|Gödel, Escher, Bach}}, where she does not control or particularly care for her ants and they don't pull ''her'' strings in any way that they 'care' about.) [[Special:Contributions/162.158.158.250|162.158.158.250]] 16:26, 3 August 2022 (UTC)<br />
:But doesn't the queen spread pheromones that control the whole population, and she is not outside thus not affected by the trails left by her workers. So it is not actually so with ants, wasps, bees and termites that they are actually mind controlled by chemicals released by their government? If I'm right the title text is completely wrong on all levels. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 07:33, 4 August 2022 (UTC)<br />
::Obviously the queen can't be directly affected by signals left outside the nest, but equally, workers outside the nest can't be affected by signals from the queen (except inasmuch as they are mediated by other members of the colony). And the queen's behaviour can be modulated by pheromones released inside the nest - such as increasing or decreasing fertility, or changing the pheromones she releases in response. Ultimately, the queen, like any other ant, can only influence the behaviour of those around her, and only does so in response to signals she herself receives - not in some kind of command control, dictatorial way. [[Special:Contributions/172.70.85.5|172.70.85.5]] 09:07, 4 August 2022 (UTC)<br />
<br />
Can't quite remember which, but I think there was another comic formatted like this. [[Special:Contributions/172.70.254.165|172.70.254.165]] 17:46, 3 August 2022 (UTC)Nafedalbi<br />
:It was [[2036:_Edgelord|2036, the one about graph theory Ph.Ds]]. [[Special:Contributions/172.70.178.103|172.70.178.103]] 18:00, 3 August 2022 (UTC)<br />
<br />
Does the caption have any relation to [[2609:_Entwives]]? I came to this explainxkcd page after reading the comic because I am not familiar with the word "entomologists". I hope somebody who knows the word can add a paragraph about the caption. --[[User:Batterystaple|Batterystaple]] ([[User talk:Batterystaple|talk]]) 07:30, 4 August 2022 (UTC)<br />
:No, as you can see from the explanation entomologists is one who study insects and this word has been used before in xkcd for that meaning. Nothing to do with Ents. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 07:34, 4 August 2022 (UTC)<br />
<br />
Do we need new categories for ants and for chemtrails? I found three other with chemtrails, added to the explanation and I think there is a bunch of ants comics. Added one with an ant researcher as here. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 07:33, 4 August 2022 (UTC)<br />
<br />
Regarding [https://www.explainxkcd.com/wiki/index.php?title=2654:_Chemtrails&diff=291978&oldid=291977], there's no need for a trivia section, just put those four links in otherwise empty squarebrackets after the first sentence of that paragraph. [[Special:Contributions/172.70.211.88|172.70.211.88]] 11:21, 4 August 2022 (UTC)<br />
<br />
"Whether ant-gland secretion signalling is Turing-equivalent was explored in Douglas Hofstadter's Gödel, Escher, Bach: an Eternal Golden Braid" and the Placebo video are trivia, but reasons explaining why the term may be annoying are speculation. [[Special:Contributions/172.69.33.223|172.69.33.223]] 11:37, 4 August 2022 (UTC)</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2653:_Omnitaur&diff=2917602653: Omnitaur2022-08-02T14:01:26Z<p>172.69.33.223: /* Explanation */ mitochondria, the powerhouse of the cell</p>
<hr />
<div>{{comic<br />
| number = 2653<br />
| date = August 1, 2022<br />
| title = Omnitaur<br />
| image = omnitaur.png<br />
| titletext = "My parents were both omnitaurs, which is how I got interested in recombination," said the normal human.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by AN OMNITAUR ZYGOTE IN A FETUS'S BODY. Do NOT delete this tag too soon.}}<br />
Omnitaur is an {{w|anagram}} of {{w|minotaur}}, a mythical creature that was part man, part bull. "{{wiktionary|omni}}" is a prefix that means "all" that is, for instance, known from the word {{w|omnivore}}, meaning 'all eating' as compared to {{w|carnivore}} or {{w|herbivore}} (only eating meat or plant respectively.) Given the combination of animals used to create the omnitaur, it could be expected that it was also an omnivore.<br />
<br />
An "omnitaur" would suggest that it would encompass all real and mythical creatures, or perhaps some random assortment of such. In this instance, it appears to be a hybrid, or {{w|Chimera (genetics)|genetic chimera}}, combined from eleven different creatures: {{w|fish}}, {{w|lion}}, {{w|snake}}, {{w|shark}}, {{w|bull}}, {{w|dragon}} (a mythical creature in its own right), {{w|horse}}, {{w|leopard}}, {{w|Sheep|ram}} (male sheep), {{w|human}} and {{w|bird}}. Chimerism is not as uncommon at the genetic level, for example humans have about 145 genes (out of around 30,000) originating from bacteria, other single-celled organisms, and viruses.[https://www.science.org/content/article/humans-may-harbor-more-100-genes-other-organisms] {{w|Mitochondria}}, the powerhouse of the cell, were originally chimeric bacteria. But chimeras of larger organisms are rare, usually involving fraternal twins whose {{w|zygote}}s or {{w|embryo}}s combined, as in {{w|conjoined twins}} but resulting in less distinct {{w|phenotype|phenotypical}} expression. Artificial human chimeras with viruses, mice, pigs, and monkeys have been the subject of ethics controversies in recent years.[https://www.theguardian.com/technology/2019/aug/11/the-five-chimeras-human-monkey-hybrid-genetic][https://jme.bmj.com/content/45/7/440.abstract]<br />
<br />
The title text is a comment by a human whose parents were both omnitaurs. It would be strange that such parents would not produce offspring that was still omnitaur. It suggests that this may be the result of {{w|genetic recombination}}, which is the exchange of genetic material between different organisms leading to production of offspring with combinations of traits that differ from those found in either parent. In this case, seemingly, they inherited ''only'' the human elements of each parent, yet sufficient to develop into a whole human with no missing or chimeric elements. Since we don't understand omnitaur genetics, we can't evaluate whether that is even plausible.<br />
<br />
===Mythical phenotypical chimeras===<br />
<br />
In addition to the minotaur, many other potential inspirations can be found in mythology, like the {{w|centaur}}, which has the upper body of a human and the lower body and legs of a horse; the {{w|manticore}}, with a body of a lion and human face; a {{w|griffin}}, with a lion's body and a eagle's head; a {{w|mermaid}}, with a lower body of a fish and upper body of a human; a {{w|Hippocampus (mythology)|hippocampus}}, with the upper body of a horse and a lower body of a fish; a {{w|qilin}}, with a body that resembles both a horse and a dragon; or the mythological {{w|chimera (mythology)|chimera}}, for which the genetic chimera is named, which has lion, snake, and goat body parts. Ultimately, there are {{w|List of hybrid creatures in folklore|lots of hybrid creatures in mythology}} with {{w|phenotype}}s combined from multiple animals. Usually, genetic hybridization produces much more smoothly blended phenotypes instead of dividing the body into large distinctly chimeric regions, although {{w|Mosaic (genetics)|mosaicism}} of fur, skin or {{w|Heterochromia iridum|eyes}} can produce notable differences of hue or shade.<br />
<br />
===Speculative implications===<br />
<br />
In {{w|C. S. Lewis}}' {{w|The Chronicles of Narnia}}, the {{w|Magical_creatures_in_The_Chronicles_of_Narnia#Centaurs|centaurs}} are described as eating two meals &mdash; a huge roast meal "to satisfy the man stomach," and a meal of grass, "to satisfy the horse stomach," making it take quite some time for them to eat every morning. Since the omnitaur also has herbivore and omnivore (as well as carnivore) parts, this could further support the supposition that it is an omnivore, and it may similarly need multiple stomachs for these multiple appetites. It is unclear how compatible the various diets of its components would be (not least because 'fish,' 'snake' and 'bird' are quite unspecific, and it's hard to know what a dragon would eat) but it would likely need several meals, taking even longer to eat than the Centaur (plus the bird beak may slow the process down quite a bit.) In any case, a chimera of both warm and cold-blooded organisms seems unlikely to be viable, even at the organ level, let alone combined surface phenotypes.<br />
<br />
Since the example depicted seems to be only <sup>1</sup>/<sub>11</sub> human, the odds of two parents as mentioned in the title text getting a fully human offspring would simplistically appear to be (<sup>1</sup>/<sub>11</sub>)<sup>11</sup>, or one chance in 285 billion. In reality, each physical part could not be the result of an equal genetic contribution, because the eleven animal chromosomes vary widely in number and size. If omnitaur genetics were governed by such principles, it would be hard to explain how a creature consisting of 11 different animals came into existence in the first place.{{cn}} [https://journals.biologists.com/dev/article/148/12/dev195792/269139/The-road-to-generating-transplantable-organs-from Interspecies blastocyst complementation,] used to create human chimera organs and cell lines in other animals, is usually limited to combining two organisms into one whose offspring are not hybridized if they are even viable.<br />
<br />
==Transcript==<br />
:[A creature, the Omnitaur, is shown. It is a four legged animal divided into 11 segments, each segment is from a different animal. An arrow goes to each section from a label, most of the labels are above the animal, but the fourth and seventh segments labels are below the animal. The animal has a fish tail and cat like hind legs. The torso is divided into four segments, the first and last of these with scales, but only the last of these also with sharp scales at the top. The second torso segment is white and smooth, the third also white but with hair both above and below, those above merges with the sharp scales of the fourth torso segment. The front legs are horse like, the lower neck is from an animal with dark spots, the upper neck has rams horns, which goes over in the central part of a human head, with ears and hair (drawn like a real human, not like a xkcd stick figure) and finally the front of the face is a bird with its eyes and a beak shown. The labels are given here in the order of the segment of the animal from the back to the front (disregarding weather the label is written above or below the animal:]<br />
:Fish<br />
:Lion<br />
:Snake<br />
:Shark<br />
:Bull<br />
:Dragon<br />
:Horse<br />
:Leopard<br />
:Ram<br />
:Human<br />
:Bird<br />
<br />
:[Caption below the panel:]<br />
:The Omnitaur<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Animals]]<br />
[[Category:Biology]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2652:_Proxy_Variable&diff=2916262652: Proxy Variable2022-08-01T12:06:52Z<p>172.69.33.223: /* Examples of noteworthy proxy variables */ renewables</p>
<hr />
<div>{{comic<br />
| number = 2652<br />
| date = July 29, 2022<br />
| title = Proxy Variable <br />
| image = proxy_variable.png<br />
| titletext = Our work has produced great answers. Now someone just needs to figure out which questions they go with.<br />
}}<br />
<br />
__NOTOC__<br />
<br />
==Explanation==<br />
{{incomplete|Created by a PROXY BOT IN NO WAY RELATED WITH THE ORIGINAL BOT, SO MARRIAGE WOULD BE ETHICALLY AND LEGALLY ACCEPTABLE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
In this comic, [[Hairy]] is discussing use of a proxy variable with [[Cueball]]. In statistics, a {{w|proxy variable}} is used as a stand-in for one or more other variables that are difficult to measure. In order to be useful as such, proxy variables must be correlated with what they are intended to represent. For example, a drug might aim to reduce deaths from a slow-acting disease. But testing if it reduces deaths might take many years, so researchers might test for a proxy outcome instead, like whether it results in loss of bone density or damage to cells. Physicians use blood pressure as one of many proxies for cardiovascular health.<br />
<br />
Hairy is dismissing the question of whether they are studying the right variable as too expensive to answer. This is deeply ironic and thus satirical, because good {{w|experiment design}} requires sufficient attention to the robustness of all the involved parts of an experiment, even if the expense may be prohibitive. This comic might be referring to the recent discovery of [https://www.science.org/content/article/potential-fabrication-research-images-threatens-key-theory-alzheimers-disease nearly two decades] of potentially fraudulent {{w|Alzheimer's disease}} research supporting a mistaken proxy hypothesis.<br />
<br />
Choosing the wrong proxy variable might make the research misleading, irrelevant, or as the title text suggests, answer the wrong question. Separating correlation from {{w|Causality|causation}} is necessary when interpreting proxy variable results to make sure the question they answer is known. Mere correlation instead of {{w|Causal analysis|authentic causation}} yields weaker results. {{w|Exploratory causal analysis}} can assist with finding useful proxy variables, but is difficult for the layperson to interpret and can be misleading, because even if performed correctly, a {{w|combinatorial explosion}} of possible proxy variables can make traditional {{w|statistical significance}} analysis fail, requiring {{w|F-score}}s or similar measures. The history of pharmaceutical research is largely a graveyard of failed proxy hypotheses; that is one of the reasons for [https://clinicaltrials.gov/ct2/manage-recs/fdaaa experiment registration regulations.]<br />
<br />
The title text's notion of having an answer without knowing the actual question could also be be a reference to the classic comedy science fiction novel {{w|The Hitchhiker's Guide to the Galaxy|The Hitchhiker's Guide to the Galaxy}}, where in one scene Earth turns out to be a supercomputer built for the purpose of figuring out the question for the answer "42."<br />
<br />
=== Examples of noteworthy proxy variables ===<br />
<br />
<!-- recap -->* Loss of bone density or damage to cells for toxicity <br />
* Blood pressure for cardiovascular health<br />
* Amyloid markers for Alzheimer's disease <br />
<br />
* Local temperature for global warming severity<br />
* GDP growth for development (demolishing a hospital adds to GDP but subtracts from development)<br />
* Money supply size for price inflation (see e.g. the {{w|paradox of thrift}})<br />
* {{W|Carbonic anhydrase}} expression for carbon sequestration<br />
* Dialytic {{w|desalination}} for carbon sequestration<br />
* Asphalt production for carbon sequestration <br />
* Proportion renewable energy for carbon reduction (see {{w|Jevons paradox}}<br />
* {{w|Bacillus thuringiensis israelensis}} application for mosquito abatement<br />
<br />
==Transcript== <br />
:[Cueball is looking at Hairy who points a pointer to a poster. On the poster there is a line graph at the top and below that a candlestick chart. The line graph appears to show a time series with a question mark inside a ellipsoid at the end of the curve. The candlestick chart shows a box-and-whiskers plot comparing two variables. There is no readable text except the question mark. Hairy's stick points just below the line chart.]<br />
:Hairy: We want to study this variable, but it's too hard to observe.<br />
:Poster: ?<br />
<br />
:[In a slim panel only Hairy and the poster are shown. His pointer now points to the left variable in the box-and-whiskers plot,]<br />
:Hairy: So we're studying this proxy variable.<br />
:Poster: ?<br />
<br />
:[Back to Cueball and Hairy with the poster out of frame. Hairy holds the pointer down by his side.]<br />
:Cueball: Is it correlated with the other variable?<br />
:Hairy: Look, we don't have the funding to answer every little question.<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Hairy]]<br />
[[Category:Science]]<br />
[[Category:Line graphs]]<br />
[[Category:Charts]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2649:_Physics_Cost-Saving_Tips&diff=2904662649: Physics Cost-Saving Tips2022-07-24T09:28:56Z<p>172.69.33.223: /* Explanation */ approximate</p>
<hr />
<div>{{comic<br />
| number = 2649<br />
| date = July 22, 2022<br />
| title = Physics Cost-Saving Tips<br />
| image = physics_cost_saving_tips.png<br />
| titletext = I got banned from the county fair for handing out Helium-2 balloons. Apparently the instant massive plasma explosions violated some local ordinance or something.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a FAUX VECTOR - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
This comic is another one of [[Randall|Randall's]] [[:Category:Tips|Tips]], this time to reduce costs or provide something for free for physicists to save money on their research. None of these would provide any real advantages even when possible to implement. It continues the previous [[2648: Chemicals]] comic's jocular theme of tricks to supposedly save money based on misinterpretations of science. Obtaining money from physics experiments was also described in [[2007: Brookhaven RHIC]].<br />
<br />
{| class="wikitable"<br />
|-<br />
! scope="col" |Cost-Saving Tip<br />
! scope="col" |Explanation<br />
|-<br />
|Try replacing regular vectors with pseudovectors whenever possible<br />
|[[File:Torque animation.gif|frame|right|Relationship of pseudovectors {{w|torque}} ('''τ''') and {{w|angular momentum}} ('''L''') to "regular" Euclidian vectors {{w|Position (vector)|position}} ('''r'''), {{w|force}} ('''F'''), and {{w|momentum}} ('''p''') in an oscillatory rotating system.]]<br />
<br />
The prefix "pseudo-" refers to an inauthentic variation of something. Fakes are usually cheaper than their original brand-name product, while often working just as well, so the comic implies a {{w|pseudovector}} could be a less expensive substitute for a regular vector. On the contrary, pseudovectors, or axial vectors, are distinct from regular {{w|Euclidean vector}}s, the former usually being involved with rotation or physical effects that share properties with rotation, similar to the relationship between angles and lengths. Pseudovectors are formed from the {{w|cross product}}s of Euclidean vectors, in three dimensions, and while similar to Euclidean vectors, there is no physical meaning to their specific direction, only their magnitude and portions of their position. For example, {{w|angular momentum}} is described by a pseudovector, labeled '''L''' in the comic, {{w|Normal (geometry)|normal}} to the {{w|plane of rotation}}, originating from the center of rotation, with magnitude equal to the angular velocity of rotation '''ω''' multiplied by the {{w|moment of inertia}} '''I'''. (The comic's diagram is drawn according to very uncommon {{w|Right-hand rule#Coordinates|left-handed coordinates}} instead of the standard {{w|right-hand rule}}. Randall is right-handed.[https://www.youtube.com/watch?v=j1tcyEo2tQk&t=28s])<br />
|-<br />
|A square wave can be broken down into an infinite supply of valuable sine waves<br />
|{{w|Fourier analysis}} can decompose any periodic function into a series of {{w|sine wave}}s. A {{w|square wave}} can thereby be represented as the sum of an infinite series of sine waves. However, the sine waves are not removed or separated individually, so such a {{w|Fourier transform}} does not produce a "supply" of sine waves for practical use in any tasks other than analysis, and as abstract mathematical objects exempt from the laws of supply and demand, their value is similarly limited.<br />
|-<br />
|Cut waste by buying lighter isotopes that don't have any dead-weight neutrons<br />
|Chemical elements are identified by the number of protons in each atomic nucleus, equal to the number of electrons in their shell (unless the atom is ionized), which dictates most of their chemical behavior. {{w|Isotopes}} are variants of the element with different numbers of neutrons in the nucleus, among which chemical behavior is usually nearly identical. The comic suggests that the neutrons don't serve any useful purpose, so, in theory, if purchasing an element by weight, and its isotopes have the same price per unit weight, then you can save money by buying isotopes with no neutrons at all. In reality, the cost per unit weight for material containing a larger concentration of normally rare isotopes, such as {{w|heavy water}} or {{w|enriched uranium}}, is much higher than the cost of material containing isotopes in their ordinary proportions. (An exception is {{w|depleted uranium}}, which costs less than regular uranium because it is a byproduct of the production of enriched uranium.) In addition, a certain range of neutron quantity is needed to keep atoms stable, as atoms with too many or too few neutrons will decay more quickly than the common isotopes. The image shown is helium-2, an {{w|Isotopes of helium|isotope of helium}} which has a half-life of less than a nanosecond. It decays into two protons, releasing a large amount of energy—hence the explosion mentioned in the title text.<br />
|-<br />
|Conductors are a great source of free electrons (may carry charges)<br />
|{{w|Charge carrier|Free}} {{w|electron}}s are electrons that are not tightly bound to specific atoms so they can move freely, such as in {{w|conduction band}}s of the {{w|metallic bond}}s throughout the iron ingot depicted in the comic. Randall interprets "free" in a different sense, meaning no cost. The charges free electrons carry are electric, not monetary as implied by the pun.<br />
|}<br />
<br />
In the title text, Randall claims to have been banned from the county fair for handing out helium-2 balloons because of the instant massive explosions caused by its radioactive decay. He jokes that violated a local ordinance. Helium balloons are often given out at county fairs and similar events, but they are filled with helium-4 and therefore inert. If a balloon was filled with helium-2, the results would be instantly explosive, comparable to about 70 tons of {{w|TNT}}. In comparison, the {{w|2020 Beirut explosion}} was equivalent to around 500 tons of TNT. Handing out what are effectively small atomic bombs at a county fair would not go down well with any surviving local authorities, so merely being banned is a very mild punishment. Criminal charges such as mass murder and terrorism would be more likely, if it weren't for the sub-nanosecond fuse length rendering the scenario absurdly impossible.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:[Title]<br />
:Physics Cost-Saving Tips<br />
<br />
:[A diagramatical spinning disc, at an angle]<br />
:[It is identified with an 'I', with a dotted axial arrow labelled 'L' and a rotational movement labelled 'ω' (small omega)]<br />
:[It sits on the left, and to the right of this is text...]<br />
:Try replacing regular vectors with pseudovectors whenever possible<br />
<br />
:[A square wave with three maxima (between four minima), and arrows pointing down into a collection of five sine waves of different wavelengths]<br />
:[One of the waves having the same frequency as the square wave and the rest of them are of shorter lengths with more peaks and troughs]<br />
:[It sits on the right, and to the left of this is text...]<br />
:A square wave can be broken down into an infinite supply of valuable sine waves<br />
<br />
:[Two atomic models]<br />
:[The left containing two protons (white with a "+" sign), two neutrons (black) and orbited by two electrons (small outlines, dotted orbits/movement lines), labelled below with the text of superscript atomic weight and element symbol]<br />
:<sup>4</sup>He<br />
:[The right model has just the two protons and the two electrons, labelled below with the text of an atomic weight and elemental symbol, and some subtext within brackets]<br />
:<sup>2</sup>He<br />
:(Decays fast - use quickly)<br />
:[Both models sit on the left of the comic, and to the right is text...]<br />
:Cut waste by buying lighter isotopes that don't have any dead-weight neutrons<br />
<br />
:[A flat rectangular bar, drawn in perspective with a scattering of dots/small circles on the top face and on the forward-facing one the label]<br />
:Iron<br />
:[An arrow points to the dots, from the text...]<br />
:Free electrons<br />
:[It sits to the right, and there is text to the left...]<br />
:Conductors are a great source of free electrons<br />
:(May carry charges)<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Tips]]<br />
[[Category:Physics]]<br />
[[Category:Chemistry]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2649:_Physics_Cost-Saving_Tips&diff=2904652649: Physics Cost-Saving Tips2022-07-24T09:26:56Z<p>172.69.33.223: /* Explanation */ not really saving</p>
<hr />
<div>{{comic<br />
| number = 2649<br />
| date = July 22, 2022<br />
| title = Physics Cost-Saving Tips<br />
| image = physics_cost_saving_tips.png<br />
| titletext = I got banned from the county fair for handing out Helium-2 balloons. Apparently the instant massive plasma explosions violated some local ordinance or something.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a FAUX VECTOR - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
This comic is another one of [[Randall|Randall's]] [[:Category:Tips|Tips]], this time to reduce costs or provide something for free for physicists to save money on their research. None of these would provide any real advantages even when possible to implement. It continues the previous [[2648: Chemicals]] comic's jocular theme of tricks to supposedly save money based on misinterpretations of science. Obtaining money from physics experiments was also described in [[2007: Brookhaven RHIC]].<br />
<br />
{| class="wikitable"<br />
|-<br />
! scope="col" |Cost-Saving Tip<br />
! scope="col" |Explanation<br />
|-<br />
|Try replacing regular vectors with pseudovectors whenever possible<br />
|[[File:Torque animation.gif|frame|right|Relationship of pseudovectors {{w|torque}} ('''τ''') and {{w|angular momentum}} ('''L''') to "regular" Euclidian vectors {{w|Position (vector)|position}} ('''r'''), {{w|force}} ('''F'''), and {{w|momentum}} ('''p''') in an oscillatory rotating system.]]<br />
<br />
The prefix "pseudo-" refers to an inauthentic variation of something. Fakes are usually cheaper than their original brand-name product, while often working just as well, so the comic implies a {{w|pseudovector}} could be a less expensive substitute for a regular vector. On the contrary, pseudovectors, or axial vectors, are distinct from regular {{w|Euclidean vector}}s, the former usually being involved with rotation or physical effects that share properties with rotation, similar to the relationship between angles and lengths. Pseudovectors are formed from the {{w|cross product}}s of Euclidean vectors, in three dimensions, and while similar to Euclidean vectors, there is no physical meaning to their specific direction, only their magnitude and portions of their position. For example, {{w|angular momentum}} is described by a pseudovector, labeled '''L''' in the comic, {{w|Normal (geometry)|normal}} to the {{w|plane of rotation}}, originating from the center of rotation, with magnitude equal to the angular velocity of rotation '''ω''' multiplied by the {{w|moment of inertia}} '''I'''. (The comic's diagram is drawn according to very uncommon {{w|Right-hand rule#Coordinates|left-handed coordinates}} instead of the standard {{w|right-hand rule}}. Randall is right-handed.[https://www.youtube.com/watch?v=j1tcyEo2tQk&t=28s])<br />
|-<br />
|A square wave can be broken down into an infinite supply of valuable sine waves<br />
|{{w|Fourier analysis}} can decompose any periodic function into a series of {{w|sine wave}}s. A {{w|square wave}} can thereby be represented as the sum of an infinite series of sine waves. However, the sine waves are not removed or separated individually, so such a {{w|Fourier transform}} does not produce a "supply" of sine waves for practical use in any tasks other than analysis, and as abstract mathematical objects exempt from the laws of supply and demand, their value is similarly limited.<br />
|-<br />
|Cut waste by buying lighter isotopes that don't have any dead-weight neutrons<br />
|Chemical elements are identified by the number of protons in each atomic nucleus, equal to the number of electrons in their shell (unless the atom is ionized), which dictates most of their chemical behavior. {{w|Isotopes}} are variants of the element with different numbers of neutrons in the nucleus, among which chemical behavior is usually nearly identical. The comic suggests that the neutrons don't serve any useful purpose, so, in theory, if purchasing an element by weight, and its isotopes have the same price per unit weight, then you can save money by buying isotopes with no neutrons at all. In reality, the cost per unit weight for material containing a larger concentration of normally rare isotopes, such as {{w|heavy water}} or {{w|enriched uranium}}, is much higher than the cost of material containing isotopes in their ordinary proportions. (An exception is {{w|depleted uranium}}, which costs less than regular uranium because it is a byproduct of the production of enriched uranium.) In addition, a certain range of neutron quantity is needed to keep atoms stable, as atoms with too many or too few neutrons will decay more quickly than the common isotopes. The image shown is helium-2, an {{w|Isotopes of helium|isotope of helium}} which has a half-life of less than a nanosecond. It decays into two protons, releasing a large amount of energy—hence the explosion mentioned in the title text.<br />
|-<br />
|Conductors are a great source of free electrons (may carry charges)<br />
|{{w|Charge carrier|Free}} {{w|electron}}s are electrons that are not tightly bound to specific atoms so they can move freely, such as in {{w|conduction band}}s of the {{w|metallic bond}}s throughout the iron ingot depicted in the comic. Randall interprets "free" in a different sense, meaning no cost. The charges free electrons carry are electric, not monetary as implied by the pun.<br />
|}<br />
<br />
In the title text, Randall claims to have been banned from the county fair for handing out helium-2 balloons because of the instant massive explosions caused by its radioactive decay. He jokes that violated a local ordinance. Helium balloons are often given out at county fairs and similar events, but they are filled with helium-4 and therefore inert. If a balloon was filled with helium-2, the results would be instantly explosive, comparable to 70 tons of {{w|TNT}}. In comparison, the {{w|2020 Beirut explosion}} was equivalent to about 500 tons of TNT. Handing out what are effectively small atomic bombs at a county fair would not go down well with any surviving local authorities, so merely being banned is a very mild punishment. Criminal charges such as mass murder and terrorism would be more likely, if it weren't for the sub-nanosecond fuse length rendering the scenario absurdly impossible.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:[Title]<br />
:Physics Cost-Saving Tips<br />
<br />
:[A diagramatical spinning disc, at an angle]<br />
:[It is identified with an 'I', with a dotted axial arrow labelled 'L' and a rotational movement labelled 'ω' (small omega)]<br />
:[It sits on the left, and to the right of this is text...]<br />
:Try replacing regular vectors with pseudovectors whenever possible<br />
<br />
:[A square wave with three maxima (between four minima), and arrows pointing down into a collection of five sine waves of different wavelengths]<br />
:[One of the waves having the same frequency as the square wave and the rest of them are of shorter lengths with more peaks and troughs]<br />
:[It sits on the right, and to the left of this is text...]<br />
:A square wave can be broken down into an infinite supply of valuable sine waves<br />
<br />
:[Two atomic models]<br />
:[The left containing two protons (white with a "+" sign), two neutrons (black) and orbited by two electrons (small outlines, dotted orbits/movement lines), labelled below with the text of superscript atomic weight and element symbol]<br />
:<sup>4</sup>He<br />
:[The right model has just the two protons and the two electrons, labelled below with the text of an atomic weight and elemental symbol, and some subtext within brackets]<br />
:<sup>2</sup>He<br />
:(Decays fast - use quickly)<br />
:[Both models sit on the left of the comic, and to the right is text...]<br />
:Cut waste by buying lighter isotopes that don't have any dead-weight neutrons<br />
<br />
:[A flat rectangular bar, drawn in perspective with a scattering of dots/small circles on the top face and on the forward-facing one the label]<br />
:Iron<br />
:[An arrow points to the dots, from the text...]<br />
:Free electrons<br />
:[It sits to the right, and there is text to the left...]<br />
:Conductors are a great source of free electrons<br />
:(May carry charges)<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Tips]]<br />
[[Category:Physics]]<br />
[[Category:Chemistry]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2649:_Physics_Cost-Saving_Tips&diff=2904642649: Physics Cost-Saving Tips2022-07-24T09:25:30Z<p>172.69.33.223: /* Explanation */ specific</p>
<hr />
<div>{{comic<br />
| number = 2649<br />
| date = July 22, 2022<br />
| title = Physics Cost-Saving Tips<br />
| image = physics_cost_saving_tips.png<br />
| titletext = I got banned from the county fair for handing out Helium-2 balloons. Apparently the instant massive plasma explosions violated some local ordinance or something.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a FAUX VECTOR - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
This comic is another one of [[Randall|Randall's]] [[:Category:Tips|Tips]], this time to reduce costs or provide something for free for physicists to save money on their research. None of these would provide any real advantages even when possible to implement. It continues the previous [[2648: Chemicals]] comic's jocular theme of tricks to supposedly save money based on misinterpretations of science. Saving money from physics experiments was also described in [[2007: Brookhaven RHIC]].<br />
<br />
{| class="wikitable"<br />
|-<br />
! scope="col" |Cost-Saving Tip<br />
! scope="col" |Explanation<br />
|-<br />
|Try replacing regular vectors with pseudovectors whenever possible<br />
|[[File:Torque animation.gif|frame|right|Relationship of pseudovectors {{w|torque}} ('''τ''') and {{w|angular momentum}} ('''L''') to "regular" Euclidian vectors {{w|Position (vector)|position}} ('''r'''), {{w|force}} ('''F'''), and {{w|momentum}} ('''p''') in an oscillatory rotating system.]]<br />
<br />
The prefix "pseudo-" refers to an inauthentic variation of something. Fakes are usually cheaper than their original brand-name product, while often working just as well, so the comic implies a {{w|pseudovector}} could be a less expensive substitute for a regular vector. On the contrary, pseudovectors, or axial vectors, are distinct from regular {{w|Euclidean vector}}s, the former usually being involved with rotation or physical effects that share properties with rotation, similar to the relationship between angles and lengths. Pseudovectors are formed from the {{w|cross product}}s of Euclidean vectors, in three dimensions, and while similar to Euclidean vectors, there is no physical meaning to their specific direction, only their magnitude and portions of their position. For example, {{w|angular momentum}} is described by a pseudovector, labeled '''L''' in the comic, {{w|Normal (geometry)|normal}} to the {{w|plane of rotation}}, originating from the center of rotation, with magnitude equal to the angular velocity of rotation '''ω''' multiplied by the {{w|moment of inertia}} '''I'''. (The comic's diagram is drawn according to very uncommon {{w|Right-hand rule#Coordinates|left-handed coordinates}} instead of the standard {{w|right-hand rule}}. Randall is right-handed.[https://www.youtube.com/watch?v=j1tcyEo2tQk&t=28s])<br />
|-<br />
|A square wave can be broken down into an infinite supply of valuable sine waves<br />
|{{w|Fourier analysis}} can decompose any periodic function into a series of {{w|sine wave}}s. A {{w|square wave}} can thereby be represented as the sum of an infinite series of sine waves. However, the sine waves are not removed or separated individually, so such a {{w|Fourier transform}} does not produce a "supply" of sine waves for practical use in any tasks other than analysis, and as abstract mathematical objects exempt from the laws of supply and demand, their value is similarly limited.<br />
|-<br />
|Cut waste by buying lighter isotopes that don't have any dead-weight neutrons<br />
|Chemical elements are identified by the number of protons in each atomic nucleus, equal to the number of electrons in their shell (unless the atom is ionized), which dictates most of their chemical behavior. {{w|Isotopes}} are variants of the element with different numbers of neutrons in the nucleus, among which chemical behavior is usually nearly identical. The comic suggests that the neutrons don't serve any useful purpose, so, in theory, if purchasing an element by weight, and its isotopes have the same price per unit weight, then you can save money by buying isotopes with no neutrons at all. In reality, the cost per unit weight for material containing a larger concentration of normally rare isotopes, such as {{w|heavy water}} or {{w|enriched uranium}}, is much higher than the cost of material containing isotopes in their ordinary proportions. (An exception is {{w|depleted uranium}}, which costs less than regular uranium because it is a byproduct of the production of enriched uranium.) In addition, a certain range of neutron quantity is needed to keep atoms stable, as atoms with too many or too few neutrons will decay more quickly than the common isotopes. The image shown is helium-2, an {{w|Isotopes of helium|isotope of helium}} which has a half-life of less than a nanosecond. It decays into two protons, releasing a large amount of energy—hence the explosion mentioned in the title text.<br />
|-<br />
|Conductors are a great source of free electrons (may carry charges)<br />
|{{w|Charge carrier|Free}} {{w|electron}}s are electrons that are not tightly bound to specific atoms so they can move freely, such as in {{w|conduction band}}s of the {{w|metallic bond}}s throughout the iron ingot depicted in the comic. Randall interprets "free" in a different sense, meaning no cost. The charges free electrons carry are electric, not monetary as implied by the pun.<br />
|}<br />
<br />
In the title text, Randall claims to have been banned from the county fair for handing out helium-2 balloons because of the instant massive explosions caused by its radioactive decay. He jokes that violated a local ordinance. Helium balloons are often given out at county fairs and similar events, but they are filled with helium-4 and therefore inert. If a balloon was filled with helium-2, the results would be instantly explosive, comparable to 70 tons of {{w|TNT}}. In comparison, the {{w|2020 Beirut explosion}} was equivalent to about 500 tons of TNT. Handing out what are effectively small atomic bombs at a county fair would not go down well with any surviving local authorities, so merely being banned is a very mild punishment. Criminal charges such as mass murder and terrorism would be more likely, if it weren't for the sub-nanosecond fuse length rendering the scenario absurdly impossible.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:[Title]<br />
:Physics Cost-Saving Tips<br />
<br />
:[A diagramatical spinning disc, at an angle]<br />
:[It is identified with an 'I', with a dotted axial arrow labelled 'L' and a rotational movement labelled 'ω' (small omega)]<br />
:[It sits on the left, and to the right of this is text...]<br />
:Try replacing regular vectors with pseudovectors whenever possible<br />
<br />
:[A square wave with three maxima (between four minima), and arrows pointing down into a collection of five sine waves of different wavelengths]<br />
:[One of the waves having the same frequency as the square wave and the rest of them are of shorter lengths with more peaks and troughs]<br />
:[It sits on the right, and to the left of this is text...]<br />
:A square wave can be broken down into an infinite supply of valuable sine waves<br />
<br />
:[Two atomic models]<br />
:[The left containing two protons (white with a "+" sign), two neutrons (black) and orbited by two electrons (small outlines, dotted orbits/movement lines), labelled below with the text of superscript atomic weight and element symbol]<br />
:<sup>4</sup>He<br />
:[The right model has just the two protons and the two electrons, labelled below with the text of an atomic weight and elemental symbol, and some subtext within brackets]<br />
:<sup>2</sup>He<br />
:(Decays fast - use quickly)<br />
:[Both models sit on the left of the comic, and to the right is text...]<br />
:Cut waste by buying lighter isotopes that don't have any dead-weight neutrons<br />
<br />
:[A flat rectangular bar, drawn in perspective with a scattering of dots/small circles on the top face and on the forward-facing one the label]<br />
:Iron<br />
:[An arrow points to the dots, from the text...]<br />
:Free electrons<br />
:[It sits to the right, and there is text to the left...]<br />
:Conductors are a great source of free electrons<br />
:(May carry charges)<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Tips]]<br />
[[Category:Physics]]<br />
[[Category:Chemistry]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=718:_The_Flake_Equation&diff=290276718: The Flake Equation2022-07-23T07:11:30Z<p>172.69.33.223: Undo revision 290266 by Theusaf hates niggers (talk)</p>
<hr />
<div>{{comic<br />
| number = 718<br />
| date = March 24, 2010<br />
| title = The Flake Equation<br />
| image = the flake equation.png<br />
| titletext = Statistics suggest that there should be tons of alien encounter stories, and in practice there are tons of alien encounter stories. This is known as Fermi's Lack-of-a-Paradox.<br />
}}<br />
<br />
==Explanation==<br />
This strip parodies the {{w|Drake equation}}, which is an method for estimating of the number of detectable extraterrestrial civilizations in our galaxy. The Drake equation starts with the best estimate for the number of stars in our galaxy, then multiplies it by successive probabilities (such as the number of stars with planets, the number of planets which can support life, etc), to ultimately calculate how many civilizations exist. While such a calculation necessarily uses speculative numbers, it gives a good sense of how many civilizations could potentially exist. <br />
<br />
The Flake equation presented in this strip provides an estimate about how many false or fake stories ''about'' aliens are likely to exist. It does so in similar manner as the Drake equation, by starting with the entire population, estimating how many people are likely to believe that they've had an alien encounter, and then calculating how likely those stories are to become public. Just like in the Drake equation, exact numbers are unknown, but can be estimated, and the equation in the comic shows [[Randall|Randall's]] guesses about these values. See an [[#Explanations of values|explanations of values]] below.<br />
<br />
"Flake" is American slang for a person who is casually dishonest or unreliable, implying that such a person would be likely to imagine an alien encounter. Note that, while the Flake equation includes people who imagine encounters "because they're crazy or want to feel special", it doesn't attempt to include outright lies or deliberate hoaxes.<br />
<br />
The final results tells us that there should be about 100,000 stories about aliens that have reliable explanations. (The numbers given in the equation gives 126,000 stories). The data is obviously highly speculative, and as with the Drake Equation, you can plug in your own numbers, but if you keep your guesses realistic, you will most likely get a very large number. This convinces the reader that the fact that there are many stories about aliens does not necessarily mean that many people actually met aliens.<br />
<br />
The title text refers to Fermi's Lack-of-a-Paradox. The {{w|Fermi paradox}} refers to the contradiction between high numbers of calculated civilizations and the total lack of verified alien contact with earth. This is related to the Drake Equation, many estimates calculate that there should be large numbers of civilization in the galaxy, and they should have existed for long periods of time, suggesting that humanity should have been contacted by them, or at least seen some clear evidence of their existence. There are multiple explanations for this paradox, but it remains a question of scientific debate. The Lack-of-a-Paradox in this strip, however, is that the math suggests that there should be huge numbers of claimed alien sightings, and that's exactly what we observe. <br />
<br />
Another comic parodying this equation is [[384: The Drake Equation]]. The credibility of paranormal reports in general is revisited in [[1235: Settled]], which posits that if such phenomena were real they should have been unambiguously captured on camera by now.<br />
<br />
===Explanations of values===<br />
{| class="wikitable"<br />
!Symbol<br />
!Assumed value<br />
!Explanation<br />
|-<br />
<br />
|W<sub>P</sub><br />
|7,000,000,000<br />
|World population at the time of the creation of the comic, taken as a starting value.<br />
|-<br />
|(C<sub>R</sub> + M<sub>i</sub>)<br />
|1/10,000 + 1/10,000<br />
|Fraction of people who would falsely believe they had been visited by aliens. This is attributed to either a person imagining an encounter, and believing that it was real (due to mental illness or a desire to feel special), or to people misinterpreting something as an alien encounter (this can include possibilities as broad as unusual lights in the sky to actual hallucinations). It is estimated that one person in ten thousand falls into each of these categories, suggesting that one person in five thousand either has or will, at some point, believe they've encountered aliens. <br />
|-<br />
|T<sub>K</sub><br />
|1/10<br />
|The fraction of people who believe they have experienced an alien sighting that tell others about their experience. [[Randall]] estimates (rather conservatively) that 90% of people who believe they've encountered aliens will keep quiet about it (likely out of fear of not being believed), and only one in ten will talk about their 'experience'. Multiplying with the previous values we get the of first-hand accounts of alien encounters. <br />
|-<br />
|F<sub>0</sub><br />
|10<br />
|Average number of people they tell about their "sightings". Multiplying with the previous values we get the number of people who hear about an alien sighting from the "primary source".<br />
|-<br />
|F<sub>1</sub><br />
|10<br />
|Average number of people that they decide to tell about the "firsthand" account. Multiplying with the previous values we get the amount of people who hear a second-hand account of a false story.<br />
|-<br />
|D<sub>T</sub><br />
|9/10<br />
|The probability that the details will be slightly adjusted during the retelling process, making the account believable. [[Randall]] estimates that 90% of accounts that are actually shared have detailed changed when they're retold. This is exceptionally common when stories are passed from person to person, it's rare for all the details to survive unchanged. In this sort of case, "not fitting the narrative" implies that some details will be unbelievable, or falsifiable, or will be insufficiently dramatic, and those tend to morph over time (often innocently, as people don't remember the original version perfectly). Multiplying this probability by the previous numbers gives number of believable-yet-false alien sighting stories in circulation.<br />
|-<br />
|A<sub>U</sub><br />
|1/100<br />
|The proportion of people who have the willingness and ability to share this story with a broad audience. [[Randall]] assumes that the overwhelming majority of people who hear such stories either have no platform to share stories to more than a handful of people at a time, or aren't willing to share these stories. But enough people in modern times have broad audiences (this number includes people with internet audiences), that it's estimated that 1% of the population both can and wants to share second-hand accounts of alien encounters. The total is now the amount of believable-yet-false alien sightings that are published to a wider audience.<br />
|}<br />
<br />
==Transcript==<br />
:{{incomplete transcript}}<br />
:The Flake Equation:<br />
:P = W<sub>P</sub> × (C<sub>R</sub> + M<sub>I</sub>) × T<sub>K</sub> × F<sub>0</sub> × F<sub>1</sub> × D<sub>T</sub> × A<sub>U</sub> ≈ 100,000<br />
:Where:<br />
::W<sub>P</sub> = World Population (7,000,000,000)<br />
::C<sub>R</sub> = Fraction of people who imagine an alien encounter because they're crazy or want to feel special (1/10,000)<br />
::M<sub>I</sub> = Fraction of people who misinterpret a physical or physiological experience as an alien sighting (1/10,000)<br />
::T<sub>K</sub> = Probability that they'll tell someone (1/10)<br />
::F<sub>0</sub> = Average number of people they tell (10)<br />
::F<sub>1</sub> = Average number of people each friend tells this "firsthand" account (10)<br />
::D<sub>T</sub> = Probability that any details not fitting the narrative will be revised or forgotten in retelling (9/10)<br />
::A<sub>U</sub> = Fraction of people with the means and motivation to share the story with a wider audience (blogs, forums, reporters) (1/100)<br />
:Even with conservative guesses for the values of the variables, this suggests there must be a ''huge'' number of credible-sounding alien sightings out there, available to anyone who wants to believe!<br />
<br />
{{comic discussion}}<br />
[[Category:Math]]<br />
[[Category:Astronomy]]<br />
[[Category:Science]]<br />
[[Category:SETI]]<br />
[[Category:Aliens]]<br />
[[Category:Statistics]]<br />
[[Category:Paranormal]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2606:_Weird_Unicode_Math_Symbols&diff=2307212606: Weird Unicode Math Symbols2022-04-19T06:47:25Z<p>172.69.33.223: /* Explanation */ space to accommodate different kerning</p>
<hr />
<div>{{comic<br />
| number = 2606<br />
| date = April 13, 2022<br />
| title = Weird Unicode Math Symbols<br />
| image = weird_unicode_math_symbols.png<br />
| titletext = U+2A0B ⨋ Mathematicians need to calm down<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by A SNAKE AVOIDING A BEE ON A WHITEBOARD - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
This comic proposes joke explanations for various {{w|unicode symbols}} with obscure or no known uses.<br />
<br />
{| class="wikitable"<br />
|+ Symbols<br />
|-<br />
! Codepoint !! Symbol !! Unicode Name !! Actual use !! Randall's meaning || Explanation<br />
|-<br />
| U+29CD || <span style="font-size: xx-large;">⧍</span> || Triangle with Serifs At Bottom || No standard use,{{citation needed}} but resembles the {{w|National Park Service}} cartographic symbol for a campsite.[https://github.com/nationalparkservice/symbol-library/] || Shark || May look like a shark fin sticking out of the water.<br />
|-<br />
| U+23E7 || <span style="font-size: xx-large;">⏧</span> || Electrical Intersection || Indicates where wires branch off || Traffic circle || Looks like a diagram of a {{w|roundabout}} as might be shown on a minimap beside a routing direction.<br />
|-<br />
| U+2A33 || <span style="font-size: xx-large;">⨳</span> || {{w|Smash product}} || The quotient of the underlying spaces of two {{w|pointed space}}s, where points in the {{w|product spaces}} are identified if they contain either labeled point as an element. || <span style="letter-spacing: 0.1em;"><span style="transform: rotate(-45deg); display: table-cell;">H</span><span style="transform: rotate(-45deg); display: table-cell;">a</span><span style="transform: rotate(-45deg); display: table-cell;">s</span><span style="transform: rotate(-45deg); display: table-cell;">h</span><span style="transform: rotate(-45deg); display: table-cell;">t</span><span style="transform: rotate(-45deg); display: table-cell;">a</span><span style="transform: rotate(-45deg); display: table-cell;">g</span></span> || Looks somewhat like the {{w|Number sign|hash}} symbol (#) – commonly used for indicating tags called {{w|hashtag}}s in social media – turned by 45 degrees.<br />
|-<br />
| U+2A7C || <span style="font-size: xx-large;">⩼</span> || Greater-Than with Question Mark Above || Used in proofs to indicate a greater-than relation that should exist but hasn't been proven yet (non-rigorous) || Confused alligator || One metaphor used when teaching inequality signs in primary school is that the sign looks like an alligator mouth "eating" the larger number. Question marks are commonly used in cartoons to indicate confusion on the part of a character.<br />
|-<br />
| U+299E || <span style="font-size: xx-large;">⦞</span> || Angle with S Inside || Plural for the angle symbol (∠) [https://www.quora.com/Unicode-How-is-the-s-in-triangle-glyph-used-in-mathematics][https://www.birdvilleschools.net/cms/lib2/TX01000797/Centricity/Domain/1114/Homework%20Helper%20Unit%203%20ch%209-10.pdf] rarely used || Snack || May look like a mouth eating an S, where the S symbolizes some snack food.<br />
|-<br />
| U+2A04 || <span style="font-size: xx-large;">⨄</span> || {{w|Arity|N-ary}} Union Operator with Plus || Disjoint union[https://books.google.com/books?id=531cAgAAQBAJ&pg=PA165&lpg=PA165&dq=%E2%A8%84&source=bl&ots=oYXkMNXP-T&sig=ACfU3U2QvMRBkD7uVG0OSumKI0JQtjTIKA&hl=en&sa=X&ved=2ahUKEwios862ypL3AhWXVTABHTnQALQQ6AF6BAgKEAM] (joining a family of sets that have no elements in common) || Drink refill || Looks like a cup with a plus to indicate adding drink to the cup.<br />
|-<br />
| U+2B48 || <span style="font-size: xx-large;">⭈</span> || Rightwards Arrow Above Reverse Almost Equal To || Pairs with <span style="font-size: x-large;">⭂</span> which could conceivably mean {{w|Assignment (computer science)|assignment}} of an {{w|Approximation|approximation}}, but neither seem to be in use. || Snakes over there || Looks like two squiggles to represent snakes and an arrow indicating the direction where they may be found.<br />
|-<br />
| U+225D || <span style="font-size: xx-large;">≝</span> || Equal To By Definition || Indicates an equation where the left side is to be defined as the right side[https://www.reddit.com/r/math/comments/1z1mty/can_someone_please_explain_the_equal_to_by/] usually used in proofs to indicate a definition is being introduced|| Definitely, for sure || "Def" is a contraction of "definitely" used in slang; the equal sign looks like a double underline, indicating heavy emphasis.<br />
|-<br />
| U+237C || <span style="font-size: xx-large;">⍼</span> || Right Angle with Downwards Zigzag Arrow || No purpose is known.[https://ionathan.ch/2022/04/09/angzarr.html] Speculation includes "Y axis continues downward," a diode with a gate, proof by contradiction, a proofreaders' mark to split a word, and indication of polarization direction. || Larry Potter || Looks like the letter "L" and a lightning bolt. {{w|Harry Potter (character)|Harry Potter}} is known for having a lightning bolt-shaped scar on his forehead. The character {{w|Legal_disputes_over_the_Harry_Potter_series#Nancy_Stouffer|Larry Potter}} figured in a fraudulent legal claim against J.K. Rowling.<br />
|-<br />
| U+2A50 || <span style="font-size: xx-large;">⩐</span> || Closed Union with Serifs and Smash Product || Indicates that a collection of topological spaces is {{w|Union-closed sets conjecture|closed}} when taking arbitrary unions and smash products. That is, if you take the union of any collection of topological spaces in the collection (even uncountably many), or the smash product of them, the result will also be in that collection. This is apparently important because the sets can't be isomorphic (one cannot be rearranged to be exactly the other.) [https://mathoverflow.net/questions/196084/counterexample-for-associativity-of-smash-product] || Spider caught with a cup and index card || Spiders or other bugs found within someone's house or workspace may be caught with a glass and something flat, often a card or a magazine, to be released outside. The projecting lines of the smash product symbol resemble the legs of a spider. Confusingly, some fonts display this symbol with different numbers of "legs": eight, as a 45°-rotated hash symbol, or six as an asterisk.<br />
|-<br />
| U+2A69 || <span style="font-size: xx-large;">⩩</span> || Triple Horizontal Bar with Triple Vertical Stroke || Emblem of the Romanian {{w|Iron Guard}} fascist political movement; possibly a four-by-four {{w|tic-tac-toe}} board.[https://pages.cs.wisc.edu/~sandlund/NumericalTicTacToe.pdf] || ℍ𝕒𝕤𝕙𝕥𝕒𝕘 || Hash symbol with one extra vertical and horizontal line, or perhaps a hash symbol which has been accidentally double-struck or overprinted.<br />
|-<br />
| U+2368 || <span style="font-size: xx-large;">⍨</span> || APL Functional Symbol Tilde Diaeresis || Used for a two-argument operation to [https://aplwiki.com/wiki/Commute commute] (swap) its arguments or allow it to use a single provided argument in both argument slots, and to convert a value into a [https://aplwiki.com/wiki/Constant constant] function || <span style="font-size: large;">:/</span> || Looks like a confused or disappointed face. Randall's use is in fact common among {{w|APL (programming language)|APL}} programmers in the comments, as documented [https://aplwiki.com/wiki/APL_Orchard#Emoticons here] and [https://aplwiki.com/wiki/Humour#Glyph_puns here].<br />
|-<br />
| U+2118 || <span style="font-size: xx-large;">℘</span> || Script Capital [''sic''] P || A stylized {{w|round hand}} 'p' used by Weierstrass for his "{{w|Weierstrass elliptic function|p-function}}," with features of both capital 𝒫&nbsp; and small 𝓅. Sometimes also used as the {{w|power set}} operator.<br />
|| Snake || This symbol coils around like a long snake, with a tapering-off tail on one end and a small "head" on the other.<br />
|-<br />
| U+2AC1 || <span style="font-size: xx-large;">⫁</span> || Subset with Multiplication Sign Below || Indicates that one set is subset of another by means of the cross product || <div style="writing-mode: vertical-rl; text-align: center;">User<br />experience</div> || Looks like the letters "Ux" sideways; UX is a common abbreviation for {{w|user experience}}.<br />
|-<br />
| U+232D || <span style="font-size: xx-large;">⌭</span> || {{w|Cylindricity}} || A symbol used in geometric dimensioning and tolerancing (GD&T) to represent a parameter called "cylindricity" which describes the statistical deviation of an ensemble of surfaces from a reference cylinder. [https://cimquest-inc.com/metrology-minute-cylindricity/ example use] || Rolling dough between your hands to shape it into a ball || Looks like two flat hands (perhaps like stick-figure arms) rolling a ball between them. Rolling dough between one's hands to make it into a ball is an important step in making many kinds of pastry and bread.<br />
|-<br />
| U+2A13 || <span style="font-size: xx-large;">⨓</span> || Line Integration with Semicircular Path Around Pole || Very rare symbol for half of a closed {{w|Contour integration|contour}} or {{w|Line integral|line}} integral which contains the {{w|Origin (mathematics)|origin}} in its interior. Contour integrals which circle the origin are very important in complex analysis. If such an integral were split into two parts, each could be represented by this symbol (which can be mistaken for <span style="font-size: x-large;">⨔</span>, the integral not including the {{w|Zeros and poles|pole}}, with a wider and more complete arc around an offset dot.) [https://math.stackexchange.com/questions/2299363/where-is-the-%E2%A8%93-integral-symbol-defined]<br />
|| Integral that avoids a bee on the whiteboard || Looks like an {{w|integral}} symbol with a bump that goes around a dot, as if a professor was drawing an integral on a whiteboard but did not want to disturb a bee that had landed right in the path of their marker.<br />
|-<br />
| U+2A0B (title text)|| <span style="font-size: xx-large;">⨋</span> || Summation with Integral || The sum of the sum of the discrete elements (∑) and the integrals (∫) over the connected pieces. This symbol requires context to be meaningful but could occur, for instance, when computing probabilities using mixed distributions.<br />
[https://twitter.com/fermatslibrary/status/1308743505309822977 see also] <br />
|| Mathematicians need to calm down || Each of the two symbols is specifically used to represent a kind of summation that is calculated completely differently from the other. Combining them could produce frustration for people unfamiliar with the usage. The comment given may make fun of mathematicians' tendency to form increasingly complex expressions in their work. It may as well be a pun on the pronounciation of the letter {{w|Esh_(letter)|Esh}} (Shhhh).<br />
|-<br />
|}<br />
<br />
This comic may have been inspired by [https://ionathan.ch/2022/04/09/angzarr.html this blog post], which went viral (in a limited sense) the same day the comic was published.<br />
<br />
==Transcript==<br />
<big>Weird Unicode Math Symbols</big><br />
<p>And their meanings</p><br />
<br />
{|<br />
| U+29CD || ⧍ || Shark<br />
|-<br />
| U+23E7 || ⏧ || Traffic circle<br />
|-<br />
| U+2A33 || ⨳ || Hashtag [the text is slanted counterclockwise]<br />
|-<br />
| U+299E || ⦞ || Snack<br />
|-<br />
| U+2A04 || ⨄ || Drink refill<br />
|-<br />
| U+2B48 || ⭈ || Snakes over there<br />
|-<br />
| U+225D || ≝ || Definitely, for sure<br />
|-<br />
| U+237C || ⍼ || Larry Potter<br />
|-<br />
| U+2A50 || ⩐ || Spider caught with a cup and index card<br />
|-<br />
| U+2A69 || ⩩ || [The word "hashtag" but with extra horizontal and vertical lines]<br />
|-<br />
| U+2368 || ⍨ || :/<br />
|-<br />
| U+2118 || ℘ || Snake<br />
|-<br />
| U+2AC1 || ⫁ || [The words "user experience" rotated clockwise 90 degrees]<br />
|-<br />
| U+232D || ⌭ || Rolling dough between your hands to shape it into a ball<br />
|-<br />
| U+2A13 || ⨓ || Integral that avoids a bee on the whiteboard<br />
|}<br />
<br />
{{comic discussion}}<br />
[[Category:Unicode]]<br />
[[Category:Math]]<br />
[[Category:Harry Potter]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=Talk:2607:_Geiger_Counter&diff=230602Talk:2607: Geiger Counter2022-04-16T17:30:06Z<p>172.69.33.223: </p>
<hr />
<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
Vanilla joke, but funny. [[User:Nafedalbi|Nafedalbi]] ([[User talk:Nafedalbi|talk]]) 18:41, 15 April 2022 (UTC)Nafedalbi<br />
:It's Randall's "dad joke". [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 19:23, 15 April 2022 (UTC)<br />
:Honestly, yeah. I impulsively went "wow... Randall's really jumped the stick figure shark." --[[Special:Contributions/172.70.110.121|172.70.110.121]] 06:32, 16 April 2022 (UTC)<br />
::Not me. After plumbing the depths of Unicode and trying to describe a Taylor series expansion from square one, this is a welcome relief. [[Special:Contributions/172.70.214.81|172.70.214.81]] 07:34, 16 April 2022 (UTC)<br />
: When does an ordinary joke become a dad joke? When it becomes apparent. [[Special:Contributions/172.70.130.121|172.70.130.121]] 10:31, 16 April 2022 (UTC)<br />
::When does it become apparent? After the delivery. [[Special:Contributions/172.69.33.223|172.69.33.223]] 17:30, 16 April 2022 (UTC)<br />
<br />
I added telegraph wires (UK-only term, possibly, and anachronistic as they are telephone cables, so feel free to change to be US-centric) and birds seem happy to sit on pole-suspended POTS cables as much as power-lines, so the linked heat-effect thing is definitely a minority necessity. I think it's just a perch. Though we probably have more signal-wires. Most(?) streets more than a few decades old have telegraph poles feeding wires to established properties (even if cable/FTTP has been dug into trenches) but mains electricity tends to have been subsurface for much longer, with only HV national/rural-area transmission grids up on pylons/poles. Obviously there ''are'' a lot more perching birds out in the countryside, where they may dominate (but still the 'telegraph' may follow road or rail routes to service the villages and isolated inhabitations along them) but you don't tend to see birds atop the larger lines at all... Too high up? ''Too'' hot? I've seen rooks/etc happily doing a Hitchcock upon a pylon itself, apparently enjoying the communal view. [[Special:Contributions/172.70.90.63|172.70.90.63]] 18:54, 15 April 2022 (UTC)<br />
<br />
For the record, [[User:Avni]] at 19:30 UTC on 2022-04-15 [https://www.explainxkcd.com/wiki/index.php?title=2607:_Geiger_Counter&diff=next&oldid=230502 deleted everything on this page]<br/><br />
--[[User:FrankHightower|FrankHightower]] ([[User talk:FrankHightower|talk]]) 04:11, 16 April 2022 (UTC)<br />
<br />
The title text joke may be understood more easily by reading "stood under" in place of "understood". [[Special:Contributions/162.158.107.124|162.158.107.124]] 19:37, 15 April 2022 (UTC)<br />
<br />
Living in Manhattan, you learn to notice when an area is full of bird droppings and avoid standing there. You also need to pay attention when parking your car. Certain lamp posts (where the lamp is cantilevered over the street) near Central Park often tend to have a large accumulation under them. [[Special:Contributions/108.162.246.178|108.162.246.178]] 19:47, 15 April 2022 (UTC)<br />
<br />
I do not understand the joke in the title text, so if somebody could please write an explanation, that would be great.<br />
Also, this is my first ever full comic description! Yay!<br />
I don't know what categories this fits in, if somebody could also put those in that would be great. [[User:MrYellow04|MrYellow04]] ([[User talk:MrYellow04|talk]]) 19:58, 15 April 2022 (UTC)<br />
:I suggest you stand under a wire with lots of birds on it for a while. It will hit you. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 20:32, 15 April 2022 (UTC)<br />
:Dirty birdy in the sky, why you do that in my eye? Boy I'm glad that cows can't fly! [[User:TCMits|TCMits]] ([[User talk:TCMits|talk]]) 14:15, 16 April 2022 (UTC)<br />
<br />
Randall, come here. Yes, right there. Stand still. THWACK! THWACK THWACK THWACK THWACK THWACK! That is all, you may go now. 20:41, 15 April 2022 (UTC)<br />
<br />
The explanation makes clear the side of the pun regarding the Geiger counting clicking, but for non-native English speakers, the phrase "it clicked" meaning "I understood" may need clarification. [[Special:Contributions/162.158.166.213|162.158.166.213]] 21:17, 15 April 2022 (UTC)<br />
<br />
I thought it meant the birds were dangerously mutated because of the radioactivity, but now I understand. [[Special:Contributions/172.69.34.84|172.69.34.84]] 22:00, 15 April 2022 (UTC)<br />
:Just make sure you don't open your mouth and tilt your head back. [[Special:Contributions/172.70.90.63|172.70.90.63]] 22:59, 15 April 2022 (UTC)<br />
<br />
Also possibly related to this news story https://www.reuters.com/world/europe/unprotected-russian-soldiers-disturbed-radioactive-dust-chernobyls-red-forest-2022-03-28/<br />
<br />
Calling the pun a parody of another joke is weird. Jokes aren’t parodied. Parodies aren’t made of general things people say. It can be a ''play on'' that other joke, but not a ''parody'' of it. It’s not ''making fun'' of the other joke. [[Special:Contributions/108.162.245.69|108.162.245.69]] 11:24, 16 April 2022 (UTC)<br />
:I somewhat agree with you. It's a 'type of' pun related to the Tom Swifty, which I edited in just now. I didn't actually remove the claim of parody. Perhaps someone else should also do that without hesitation... (...says I, unerringly!) [[Special:Contributions/162.158.159.43|162.158.159.43]] 15:06, 16 April 2022 (UTC)<br />
<br />
Dates for the Trinity Site Open House are April 2 and October 15 for 2022. Bring your own geiger counter. [[User:TCMits|TCMits]] ([[User talk:TCMits|talk]]) 14:15, 16 April 2022 (UTC)<br />
:...and possibly a time-machine? ;) [[Special:Contributions/162.158.159.43|162.158.159.43]] 15:06, 16 April 2022 (UTC)<br />
<br />
== Leonard Cohen reference? ==<br />
<br />
It seems to me that the title text has to be somehow referencing one of Leonard Cohen’s better known songs, “Bird on the Wire”, from the very specific phrasing there. [[Special:Contributions/108.162.245.69|108.162.245.69]] 11:21, 16 April 2022 (UTC)<br />
: It's a fairly common phrase. Including the 1990 Goldie Hawn / Mel Gibson<br />
[https://g.co/kgs/QZ6LpN film]. [[User:Iggynelix|Iggynelix]] ([[User talk:Iggynelix|talk]]) 16:23, 16 April 2022 (UTC)</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2572:_Alien_Observers&diff=2284912572: Alien Observers2022-03-16T03:56:25Z<p>172.69.33.223: /* Trivia */ don't need specifically, already added</p>
<hr />
<div>{{comic<br />
| number = 2572<br />
| date = January 24, 2022<br />
| title = Alien Observers<br />
| image = alien_observers.png<br />
| titletext = ALERT: Human 910-25J-1Q38 has created a Youtube channel. Increase erratic jerkiness of flying by 30% until safely out of range.<br />
}}<br />
*This was the seventh comic to come out after the [[Countdown in header text]] started.<br />
<br />
==Explanation==<br />
This strip depicts a group of aliens observing earth, and discussing their "restricted flight zone", which they appear to change each time a human acquires a more powerful camera. <br />
<br />
This comic was followed directly by [[2573: Alien Mission]], where aliens use similar looking flying-saucer type spacecrafts to observe Earth. It is not specifically stated that these two form a series, but the next comic could be seen as a direct follow up to the this one, indicating that the aliens are the same in the two comics. Just 7 comics later [[2579: Tractor Beam]] also used similar spacecraft.<br />
<br />
Both strips are based on {{w|UFO conspiracy theories}}, which are common in the US and a number of other countries. It is often claimed that {{w|Unidentified Flying Objects}} seen in the sky are, in fact, extraterrestrial space craft, visiting earth for various reasons. Reports of such sightings have existed for a long time, and ever since cameras became widely available, photographs (and later videos) have been produced which are claimed to show such flying vessels. Almost invariably, these images are sufficiently distant, blurry, or otherwise obscured as to make any kind of detailed identification impossible - they could not be ''Unidentified'' Flying Objects if it were possible to identify them!<br />
<br />
This strip lampoons such ideas by positing that aliens are real, but deliberately maintain a distance such that no clear photographs can be taken. While this concept might seem initially plausible, it doesn't stand up to examination. Over the past several decades, cameras have become far more common, with most of the population of many countries [[1235:_Settled|carrying cameras every waking moment]] (and even sleeping with those same cameras within reach). At the same time, cameras available to the average consumer have dramatically increased in resolution and zooming capabilities. The same shot that resulted in blurry and vague photographs in early digital photography could result in much more detailed images today, and also overcome many of the pitfalls associated with 'analogue' photography without sufficient skill and/or bulky equipment. What's more, the cameras owned by individual consumers have a wide range of resolutions and other capabilities, meaning that an image that would show little detail from one person's camera could result in highly detailed photograph if someone else took a picture. The fact that improving camera technology has not resulted in improved images of these supposed vessels is an impossibly weak point in these conspiracy theories.<br />
<br />
The humorous premise of the strip is that these aliens are real, and are monitoring earth, but are taking deliberate actions to keep evidence of their presence ambiguous. To do this, they would need to not only monitor what camera technology exists on earth, but the exact type of camera each individual owns, and maintain their flights right at the outer visual limit of those cameras. Such information would need to be implausibly detailed, and constantly updated, because technology is constantly improving and people are constantly getting new phones with new cameras. Part of the joke is that the aliens would have to know the visual range of our cameras, but instead of remaining safely outside of it (so that no pictures of their vessels could be taken at all), they stay close enough to be seen, but never close enough for detailed images. <br />
<br />
In a broader sense, this strip addresses the same issue as previous strips, such as [[718: The Flake Equation]] and [[1235: Settled]], in which the phenomenon of UFO sightings/reports is still left not resolved (either way) despite what modern technology should suggest is possible. The suggestion is that this trend either means that {{tvtropes|SufficientlyAdvancedAlien|sufficiently advanced aliens}} are deliberately leaving ambiguous evidence of their presence, or that no such alien visitors are here, and the purported evidence is either faked, or misinterpretations of other phenomena. It's pretty clear which explanation [[Randall]] favors. <br />
<br />
In the title text, the aliens note that one particular human now has a YouTube account, meaning they are likely to record video instead of attempting to capture still images. This means that the alien craft used to create the sighting must behave as erratically as possible, in order to avoid being identified. This relates to the often wildly oscillating (as well as blurry) films and videos of 'UFOs' that have been taken by the impromptu human observer beyond the limit of their ability to hold their fully-zoomed camera steady. Here it is explained as the flying saucers ''actually'' moving in an improbably jerky manner to prevent detailed recording of their craft. Further briefings of the sort depicted would doubtless accompany upgrades in optical/digital-stability features or the purchase of a camera tripod.<br />
<br />
The identifier for the one buying the phone begins with "Human 38XT11". This seems likely to be a reference to {{w|THX 1138}} as this was the title of {{w|George Lucas}}'s first film, which is also {{w|THX_1138#Etymology_and_references|referenced}} in the original {{w|Star Wars (film)|Star Wars}} film. The name contains the number in reverse, as well as the letters, if "human" could be written as H.<br />
<br />
==Transcript==<br />
:[Three aliens are looking at a screen. They each have six tentacles, of which four are used as legs, and the other two can be used as arms. They also have a small mouth and two eye stalks with a large eye at the end of each. The eyes has large eyelashes all the way around. One of the aliens is standing to the left of the screen, pointing to it by raising one of its tentacles. The other two aliens stand to the right of the screen looking at the picture. The screen's image depicts a cross-sectional diagram showing two humans in a rough landscape. There is a shaded area above each of the humans and the terrain. The shaded area's boundary consists of arcs of differing sizes centered upon each human. To the left of the first human there is also a small straight area over the ground. To the left of this towards the edge of the screen, what appears to be an arc with a very large radius that begins and rises high up compared to the other two arcs, around a point beyond the on-screen image's edge. The rightmost human's zone has a dashed region between concentric radii of different sizes indicating that this zone has been revised further out than before. Four flying-saucer like spaceships are shown in the air close to, but above, the shaded areas. One high near the left curve, one over the flat area, one near the intersection between the two small arcs and one over the middle of the right arc.]<br />
:Left Alien: Human 38XT11-B-C54 <!-- 11 or II? --> just bought a new phone with a 10x zoom, so we have to expand our restricted flight zone by 1,800 meters to keep our ship blurry.<br />
:Right Alien 2: Seriously? Didn't they '''''just''''' upgrade?<br />
:Left Alien: I know, I know...<br />
<br />
:[Caption below the panel:]<br />
:The hardest part of being an alien observing Earth is keeping track of what cameras everyone has.<br />
<br />
==Trivia==<br />
* The aliens depicted here appear to be the same lifeforms as seen in the bottom row of [[2359: Evidence of Alien Life]].<br />
* They also have similarities to the illustration in the [[what if]] ''{{what if|20|Diamond}}''.<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Aliens]]<br />
[[Category:Smartphones]]<br />
[[Category:Conspiracy theory]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2587:_For_the_Sake_of_Simplicity&diff=2277662587: For the Sake of Simplicity2022-03-01T02:48:13Z<p>172.69.33.223: /* Explanation */ wlinks</p>
<hr />
<div>{{comic<br />
| number = 2587<br />
| date = February 28, 2022<br />
| title = For the Sake of Simplicity<br />
| image = for_the_sake_of_simplicity.png<br />
| titletext = For the sake of simplicity, gardeners are assumed to move through Euclidean space--neglecting the distortion from general relativity--unless they are in the vicinity of a Schwarzschild Orchid.<br />
}}<br />
<br />
==Explanation==<br />
<br />
{{incomplete|Created, '''for the sake of simplicity''', by a SCHWARZSCHILD ORCHID - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
[[Cueball]] appears to be explaining a gardening-related board game to [[Ponytail]] and [[White Hat]]. The game mechanics being employed are ridiculously overcomplicated for a game that seems to be about gardening, but Cueball insists that they have been chosen "for the sake of simplicity", and could have been ''even more'' complicated.<br />
<br />
Features of the game include:<br />
* Tokens to represent competing gardeners<br />
* Plots for the players to garden, both home plots and secondary garden plots<br />
* Mechanics to assign speed of transit between plots<br />
* Gardener attributes, including height, cardio scores and stamina scores<br />
* Hereditary trees to determine gardener attributes according to the gardener's ancestry - {{w|matrilineally}} refers to inheritance from the mother's side<br />
* Euclidean and non-euclidean space, in accordance with the theory of {{w|special relativity}}. <br />
* The presence of particular species of flora that can warp {{w|space-time}}<br />
<br />
The title text mentions that the space is assumed to be {{w|Euclidean_Geometry|Euclidean}}, which is what most people would assume since it corresponds to our normal experience, so this is not something that normally needs to be explained. But then it says that this isn't true in the vicinity of a Schwarzchild Orchid. An {{w|orchid}} is a type of flowering plant, which is relevant to a gardening game, but Schwarzchild refers to {{w|Karl Schwarzchild}}, a physicist who solved equations related to {{w|general relativity}}; the {{w|Schwarzschild radius}} is the boundary of a {{w|black hole}}, and spacetime is severely warped in this vicinity, so Euclidean geometry and {{w|Newton's Laws}} don't describe motion here well.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
:[Cueball is standing beside Ponytail and White Hat, who are sitting at a table with a board game.]<br />
<br />
:Cueball: You may assign each gardener's token to a secondary garden plot within a 30-minute walk from their home plot.<br />
:Cueball: For the sake of simplicity, each gardener is assumed to have a constant walking speed proportional to their height and cardio score.<br />
:Cueball: For the sake of simplicity, stamina scores are inherited matrilineally...<br />
<br />
:[Caption below the panel:]<br />
:If you're worried that you're making something too complicated, just add "for the sake of simplicity" now and then as a reminder that it could always be worse.<br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Ponytail]]<br />
[[Category:Comics featuring White Hat]]<br />
[[Category:Board games]]<br />
[[Category:Language]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2587:_For_the_Sake_of_Simplicity&diff=2277652587: For the Sake of Simplicity2022-03-01T02:46:43Z<p>172.69.33.223: /* Transcript */ ce</p>
<hr />
<div>{{comic<br />
| number = 2587<br />
| date = February 28, 2022<br />
| title = For the Sake of Simplicity<br />
| image = for_the_sake_of_simplicity.png<br />
| titletext = For the sake of simplicity, gardeners are assumed to move through Euclidean space--neglecting the distortion from general relativity--unless they are in the vicinity of a Schwarzschild Orchid.<br />
}}<br />
<br />
==Explanation==<br />
<br />
{{incomplete|Created, '''for the sake of simplicity''', by a SCHWARZSCHILD ORCHID - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
[[Cueball]] appears to be explaining a gardening-related board game to [[Ponytail]] and [[White Hat]]. The game mechanics being employed are ridiculously overcomplicated for a game that seems to be about gardening, but Cueball insists that they have been chosen "for the sake of simplicity", and could have been ''even more'' complicated.<br />
<br />
Features of the game include:<br />
* Tokens to represent competing gardeners<br />
* Plots for the players to garden, both home plots and secondary garden plots<br />
* Mechanics to assign speed of transit between plots<br />
* Gardener attributes, including height, cardio scores and stamina scores<br />
* Hereditary trees to determine gardener attributes according to the gardener's ancestry<br />
* Euclidean and non-euclidean space, in accordance with the theory of special relativity. <br />
* The presence of particular species of flora that can warp space-time<br />
<br />
The title text mentions that the space is assumed to be {{w|Euclidean_Geometry|Euclidean}}, which is what most people would assume since it corresponds to our normal experience, so this is not something that normally needs to be explained. But then it says that this isn't true in the vicinity of a Schwarzchild Orchid. An {{w|orchid}} is a type of flowering plant, which is relevent to a gardening game, but Schwarzchild refers to {{w|Karl Schwarzchild}}, a physicist who solved equations related to {{w|General Relativity}}; the {{w|Schwarzschild radius}} is the boundary of a {{w|black hole}}, and spacetime is severely warped in this vicinity, so Euclidean geometry and {{w|Newton's Laws}} don't describe motion here well.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
:[Cueball is standing beside Ponytail and White Hat, who are sitting at a table with a board game.]<br />
<br />
:Cueball: You may assign each gardener's token to a secondary garden plot within a 30-minute walk from their home plot.<br />
:Cueball: For the sake of simplicity, each gardener is assumed to have a constant walking speed proportional to their height and cardio score.<br />
:Cueball: For the sake of simplicity, stamina scores are inherited matrilineally...<br />
<br />
:[Caption below the panel:]<br />
:If you're worried that you're making something too complicated, just add "for the sake of simplicity" now and then as a reminder that it could always be worse.<br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Ponytail]]<br />
[[Category:Comics featuring White Hat]]<br />
[[Category:Board games]]<br />
[[Category:Language]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2587:_For_the_Sake_of_Simplicity&diff=2277642587: For the Sake of Simplicity2022-03-01T02:44:52Z<p>172.69.33.223: /* Transcript */ fix up</p>
<hr />
<div>{{comic<br />
| number = 2587<br />
| date = February 28, 2022<br />
| title = For the Sake of Simplicity<br />
| image = for_the_sake_of_simplicity.png<br />
| titletext = For the sake of simplicity, gardeners are assumed to move through Euclidean space--neglecting the distortion from general relativity--unless they are in the vicinity of a Schwarzschild Orchid.<br />
}}<br />
<br />
==Explanation==<br />
<br />
{{incomplete|Created, '''for the sake of simplicity''', by a SCHWARZSCHILD ORCHID - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
[[Cueball]] appears to be explaining a gardening-related board game to [[Ponytail]] and [[White Hat]]. The game mechanics being employed are ridiculously overcomplicated for a game that seems to be about gardening, but Cueball insists that they have been chosen "for the sake of simplicity", and could have been ''even more'' complicated.<br />
<br />
Features of the game include:<br />
* Tokens to represent competing gardeners<br />
* Plots for the players to garden, both home plots and secondary garden plots<br />
* Mechanics to assign speed of transit between plots<br />
* Gardener attributes, including height, cardio scores and stamina scores<br />
* Hereditary trees to determine gardener attributes according to the gardener's ancestry<br />
* Euclidean and non-euclidean space, in accordance with the theory of special relativity. <br />
* The presence of particular species of flora that can warp space-time<br />
<br />
The title text mentions that the space is assumed to be {{w|Euclidean_Geometry|Euclidean}}, which is what most people would assume since it corresponds to our normal experience, so this is not something that normally needs to be explained. But then it says that this isn't true in the vicinity of a Schwarzchild Orchid. An {{w|orchid}} is a type of flowering plant, which is relevent to a gardening game, but Schwarzchild refers to {{w|Karl Schwarzchild}}, a physicist who solved equations related to {{w|General Relativity}}; the {{w|Schwarzschild radius}} is the boundary of a {{w|black hole}}, and spacetime is severely warped in this vicinity, so Euclidean geometry and {{w|Newton's Laws}} don't describe motion here well.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
:[Cueball is standing beside Ponytail and White Hat, who are sitting at a table with a board game.]<br />
<br />
:Cueball: You may assign each gardener's token to a secondary garden plot within a 30-minute walk from their home plot. For the sake of simplicity, each gardener is assumed to have a constant walking speed proportional to their height and cardio score. For the sake of simplicity, stamina scores are inherited matrilineally...<br />
<br />
:[Caption below the panel:]<br />
:If you're worried that you're making something too complicated, just add "for the sake of simplicity" now and then as a reminder that it could always be worse.<br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Ponytail]]<br />
[[Category:Comics featuring White Hat]]<br />
[[Category:Board games]]<br />
[[Category:Language]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=Talk:2587:_For_the_Sake_of_Simplicity&diff=227756Talk:2587: For the Sake of Simplicity2022-02-28T23:16:22Z<p>172.69.33.223: </p>
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<div>--[[User:RIIW - Ponder it|RIIW - Ponder it]] ([[User talk:RIIW - Ponder it|talk]]) 23:04, 28 February 2022 (UTC)<!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
So many modern board games are made complex by complex rules, but remain simplistic. Go is very simple (grid of nineteen lines, two types of pieces, and about three rules, but is arguably the most inherently complex game in existence. [[User:RIIW - Ponder it|RIIW - Ponder it]] ([[User talk:RIIW - Ponder it|talk]]) 23:04, 28 February 2022 (UTC)<br />
<br />
Schwarzschild's radius of a mass is the radius of a black hole with equivalent mass. So a Swarchtnhsnthn orchid has similar space warping properties to a black hole. [[Special:Contributions/172.69.33.223|172.69.33.223]] 23:16, 28 February 2022 (UTC)</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=Talk:2343:_Mathematical_Symbol_Fight&diff=195810Talk:2343: Mathematical Symbol Fight2020-08-09T21:47:58Z<p>172.69.33.223: /* Would anyone else like to join me in creating an anti-Gamma interest group? */ new section</p>
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<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
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Can I get aleph-null aleph-shaped throwing stars? [[User:LunarNapolean|LunarNapolean]] ([[User talk:LunarNapolean|talk]]) 20:18, 7 August 2020 (UTC)<br />
<br />
Apologies to whoever added the "citation needed" that I stepped on. -- brad<br />
<br />
That zeta looks conspicuously bad. I wonder if this comic will get a cleaned-up version uploaded. [[Special:Contributions/108.162.237.16|108.162.237.16]] 20:51, 7 August 2020 (UTC)<br />
<br />
[[Megan]] usually has shoulder-length hair, so the person being attacked by Ponytail is probably not Megan... except in so far as all brunettes in this comic are called 'Megan'. [[User:LtPowers|LtPowers]] ([[User talk:LtPowers|talk]]) 20:53, 7 August 2020 (UTC)<br />
:Is one of them [[Danish]]? And one of them Megan? [[Special:Contributions/172.69.33.121|172.69.33.121]] 22:49, 7 August 2020 (UTC)<br />
<br />
I think Randall is underestimating the weapon utility of psi. There's a real-world martial arts [https://en.wikipedia.org/wiki/Sai_(weapon) weapon] that looks somewhat like it.[[Special:Contributions/172.69.68.197|172.69.68.197]] 22:04, 7 August 2020 (UTC)<br />
:I think he’s also seriously underestimating the value of keeping your fingers attached to your hand. Swords have guards for a reason. I’d pick the contour integral over anything else there.<br />
<br />
Considering the title text, a bass clef looks pretty formidable, close to a bat'leth. [[User:Nutster|Nutster]] ([[User talk:Nutster|talk]]) 00:31, 8 August 2020 (UTC)<br />
:Yes, but the treble clef is the one in the title text, and that’s nothing like a Klingon {{w|bat'leth}}. I removed the comment from the table. [[User:Adam1729|Adam1729]] ([[User talk:Adam1729|talk]]) 02:09, 8 August 2020 (UTC)<br />
<br />
These “weapons” seem strangely appropriate for xkcd’s stick figures... -cpl<br />
: Agreed :)<br />
<br />
Are we sure White Hat is holding empty set? There don't appear to be points extending outside the circle in which case I think he's actually holding Theta -jc<br />
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Can I use the LaTeX mathwitch? [[Special:Contributions/141.101.98.26|141.101.98.26]] 10:03, 8 August 2020 (UTC)<br />
<br />
First time editor here,hope I get the notation right! Question on the pi link to wikipedia: I put in the double link to the main page and the disambiguation because unfortunately https://en.wikipedia.org/wiki/Pi_(disambiguation)#Mathematics doesn't include the mathematical constant definition (though it is listed at the top of the page). Thoughts? [[User:Alan g|Alan g]] ([[User talk:Alan g|talk]]) 10:38, 8 August 2020 (UTC)<br />
<br />
I think that’s the is proportional to” symbol rather than just alpha. They are similar but have different Unicode symbols. Thoughts?--[[Special:Contributions/141.101.98.222|141.101.98.222]] 12:01, 8 August 2020 (UTC)<br />
:You're definitely correct. (They don't even look that similar...) It's the direct proportion symbol, not the symbol for Alpha. <br />
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 18:03, 8 August 2020 (UTC)<br />
I don't think → is "implies", particularly as we've had ⇒ earlier. → is often used for "maps to", as in f: x → f(x) [[Special:Contributions/141.101.107.166|141.101.107.166]] 19:24, 8 August 2020 (UTC)<br />
:→ and ⇒ often mean two different kinds of "implies". The single arrow is for the boolean operator that takes in two truth values and outputs a truth value. The double one is for "things on the left justify/prove things on the right", in somewhat of a metalanguage. Here's an example of two different ways of saying Modus Ponens with the operators: ((p→q) ∧p)→q vs p→q,p⇒q [[User:Alan g|Alan g]] ([[User talk:Alan g|talk]]) 03:52, 9 August 2020 (UTC)<br />
Are we sure that is the multiplication sign (center dot)? The placement makes it seem more a decimal point. [[Special:Contributions/162.158.123.47|162.158.123.47]] 21:51, 8 August 2020 (UTC)<br />
:Confusingly, math conventions in some countries use a low dot for multiplication, though it's not as common as it used to be. That's in addition to all the other things that bare dots can represent in math. Personally I can't "see" any particular set of semantics for that symbol, I just see a dot. [[Special:Contributions/162.158.186.136|162.158.186.136]] 22:51, 8 August 2020 (UTC)<br />
We see a greater-than, but no less-than. Where would that appear? I think >≠<, in fact ><<, if wielded properly. Though if thrown, either/both could be a multi-use projectile... [[Special:Contributions/141.101.98.96|141.101.98.96]] 09:08, 9 August 2020 (UTC)<br />
: Took me a little bit to figure out what you meant, but I think it hasn't been clarified which side is the point or sharp side, so until that is clarified "<"=">"<br />
<br />
Anyone else think the title text is hinting at a pun? "I got scared because his weapon looked like treble" sort of thing?<br />
<br />
Where is the opening parenthesis? [[Special:Contributions/172.69.33.223|172.69.33.223]] 21:43, 9 August 2020 (UTC)<br />
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== Would anyone else like to join me in creating an anti-Gamma interest group? ==<br />
<br />
Just asking. [[Special:Contributions/172.69.33.223|172.69.33.223]] 21:47, 9 August 2020 (UTC)</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2343:_Mathematical_Symbol_Fight&diff=1958092343: Mathematical Symbol Fight2020-08-09T21:46:26Z<p>172.69.33.223: /* Explanation */ radix</p>
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<div>{{comic<br />
| number = 2343<br />
| date = August 7, 2020<br />
| title = Mathematical Symbol Fight<br />
| image = mathematical_symbol_fight.png<br />
| titletext = Oh no, a musician just burst in through the door confidently twirling a treble clef.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a RADIX SCYTHE. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}<br />
<br />
This panel imagines which {{w|List of mathematical symbols|mathematical symbols}} would be good in a fight if they were made corporeal in two (or three) dimensions. Generally, objects with longer reach and pointier ends wind up on the right ("more useful") side of the scale, and symbols with less reach and more curves tend towards the left ("less useful") side. <br />
<br />
The comic invokes [[wikipedia:surreal humour|surreal humour]] by suggesting that mathematical symbols could be handled as physical objects in the real world. Another component of the humor is the implication that it is useful to prepare to use mathematical symbols in a fight, even though mathematicians, who use mathematical symbols, usually do not conduct their debates violently <ref>S. Lee and S. Miller,, ''Crystal Dragon'',(Baen, 2005), chapter eight</ref> (though some stories suggest that {{w|Hippasus}} was killed by his fellow Pythagoreans for his proof that irrational numbers exist), and even if they did, they wouldn't use large reproductions of their symbols as weapons.<br />
<br />
{| class="wikitable"<br />
! Symbol<br />
! Meaning<br />
! Notes on using in a fight<br />
|-<br />
|<span style="font-size:150%"> ℝ</span><br />
|The set of [[wikipedia:real number|real number]]s<br />
|Megan seems to be struggling with a giant version of this symbol.<br />
|-<br />
|<span style="font-size:150%"> θ</span><br />
|[[wikipedia:Theta#Mathematics_and_science|Theta]]<br />
|This symbol is not very sharp, and [[White Hat]] is unable to use it in combat. It would not work as a good shield due to the hole in the symbol, but it possibly could be thrown. (The later version of Xena's chakram had a bar in the middle.)<br />
|-<br />
|<span style="font-size:150%"> ∅</span><br />
|[[wikipedia:Empty set|Empty set]]<br />
|Similarly shaped to theta, but identified as being slightly more useful, presumably because the parts of the bar that extend beyond the circle can be used as thrusting weapons. Alternatively, the round nature of the symbol makes it easier to handle for defense, by holding on to the line and using the edge of the circular part to block.<br />
|-<br />
|<span style="font-size:150%"> ∞</span><br />
|infinity<br />
|Could be gripped between the rings and used as a blunt instrument.<br />
|-<br />
|<span style="font-size:150%"> ></span><br />
|Greater than<br />
|Could be used to thrust with the point, but lacks a grip by which to do so.<br />
|-<br />
|<span style="font-size:150%"> ∝</span><br />
|[[wikipedia:Proportionality_(mathematics)#Direct_proportionality|Direct Proportionality]]<br />
|Could be brandished by the ring and used to thrust with the prongs, but the two prongs extending at 90-degree angles make thrusting motions awkard.<br />
|-<br />
|<span style="font-size:150%"> ∪</span><br />
|{{w|union (set theory)}}<br />
|Could be used as a boomerang, which is {{tvtropes|PrecisionGuidedBoomerang|notoriously less practical in real life than in fiction}}<br />
|-<br />
|<span style="font-size:150%"> ∈/ϵ</span><br />
|{{w|Element (mathematics)|member of}} (set theory) or the "lunate" lowercase {{w|Epsilon#Symbol|epsilon}}<br />
|Cueball is holding this in the manner of a Klingon "{{w|Bat'leth}}" from the ''Star Trek'' franchise. The Bat'leth is [https://youtu.be/VsElSDXPgSA infamous] among swordfighters for being rather impractical, and that the Klingon warrior race would have been better suited using swords like humans. It seems Randall agrees, as the ∈ is quite far on the left of the chart.<br />
|-<br />
|<span style="font-size:150%"> π</span><br />
|[[wikipedia:Pi|pi]]<br />
|Could be used as a hammer, but the two handles (or a single board-like grip) would make doing so impractical.<br />
|-<br />
|<span style="font-size:150%"> ∀</span><br />
|"{{w|Universal quantification|for all}}"<br />
|Could be held by the crossbar clenched in a fist, and then used as a {{w|push dagger}}, with the legs acting as a guard. Or could be held by the legs.<br />
Compared to the similar Δ (delta) the point is sharper, the grip is closer to the point so it would be easier control (keep the weapon from twisting). Unclear why it is listed as much less effective than the delta. Perhaps the guard legs are too long?<br />
|-<br />
|<span style="font-size:150%"> ∂</span><br />
|{{w|∂}} ([[wikipedia:Partial derivative|partial derivative]] or [[wikipedia:Boundary_(topology)|boundary operator]])<br />
|It's not clear why Randall ranks this symbol as so much less effective than the similarly-shaped 𝜌, but the curl in the "tail" of the ∂ would give it a shorter lever arm when swung and would disrupt the balance.<br />
|-<br />
|<span style="font-size:150%"> +</span><br />
|[[wikipedia:Plus_and_minus_signs#Plus_sign|Plus]]<br />
|Maybe thrown like a {{w|shuriken}}?<br />
|-<br />
|<span style="font-size:150%"> Ψ</span><br />
|[[wikipedia:Psi#Mathematics|Psi]]<br />
|It could be used as a slightly-less-functional trident or pitchfork, with a shorter handle. More particularly, it resembles a {{w|Sai (weapon)|sai}} (which, funnily enough, is how "Psi" is pronounced).<br />
|-<br />
|<span style="font-size:150%"> ≠</span><br />
|not equal sign<br />
|Could be gripped by the crossbar, using the lengths to puncture. Notably, the equal sign (=) is absent from the chart, likely because the lengths are separate and would not be used as a single entity.<br />
|-<br />
|<span style="font-size:150%"> ~</span><br />
|[[wikipedia:Tilde#Mathematics|tilde]], meaning "approximately", equivalent, or several transforms of a function<br />
|A potentially dangerous throwing weapon. Could also be similar to a wavy bladed dagger ({{w|Kris}}) or a sword ({{w|Flame-bladed sword}}).<br />
|-<br />
|<span style="font-size:150%"> #</span><br />
|[[wikipedia:Cardinality|Cardinality]], [[wikipedia:Connected_sum|connected sum]] (knot theory), or [[wikipedia:Primorial|primorial]].<br />
|Blondie uses this symbol, gripping it by two of the prongs on one side. The other three prongs could thus be swung at opponents, but being sharp on all sides would pose a threat to the user as well as the opponent.<br />
|-<br />
|<span style="font-size:150%"> Δ</span><br />
|[[wikipedia:Delta_(letter)|Delta]]<br />
|Could be held with one bar clenched in a fist, and then used as a {{w|push dagger}}. Unclear why listed as much more effective than ∀. Also, delta could be thrown like a star.<br />
|-<br />
|<span style="font-size:150%"> ⇒</span><br />
|[[wikipedia:Material_conditional|Material consequence]] or [[wikipedia:Logical_consequence|Logical consequence]], meaning "implies"<br />
|The point is nice, but having two poles (or one board-like thick handle) would be difficult to wield. A collection of them might make a nice defensive pike line.<br />
|-<br />
|<span style="font-size:150%"> ⋅</span><br />
|multiplication sign<br />
|Functionally a ball, and could therefore be thrown as a projectile weapon, or scattered on the ground as a trip hazard.<br />
|-<br />
|<span style="font-size:150%"> ζ</span><br />
|{{w|Zeta#Mathematics_and_science|Zeta}}<br />
|Could be sharpened into a scythe or curved saber, depending on the curvature and length of the 'tail' at the bottom.<br />
|-<br />
|<span style="font-size:150%"> ℵ</span><br />
|[[wikipedia:Aleph_number|Aleph number]]<br />
|The irregular shape of the symbol leads to edges and points on all sides; thus it could be brandished or thrown in the manner of a shuriken.<br />
|-<br />
|<span style="font-size:150%"> Γ</span><br />
|uppercase Greek letter {{w|Gamma#Uppercase|Gamma}}<br />
|If this letter is formed with {{w|serif}}s, it could be used as an axe or hook, and if it is made {{w|sans-serif}}, it would make a powerful pick or war hammer.<br />
|-<br />
|<span style="font-size:150%"> √</span><br />
|{{w|radix}} sign<br />
|Randall has drawn this sign with a long overbar, which makes it useful like a {{w|Pole weapon|pole arm}}. Black Hat has chosen this symbol.<br />
|-<br />
|<span style="font-size:150%"> ''ρ''</span><br />
|{{w|Prime_constant|italic rho}}<br />
|Ponytail is brandishing this symbol against Danish, apparently using it like a club or hammer and striking with the curve.<br />
|-<br />
|<span style="font-size:150%"> ∮</span><br />
|{{w|contour integral}}<br />
|This symbol is drawn with a very tight center, giving it an almost identical figure to the regular integral symbol. Presumably, the added bulk for marginal additional use earns it a rating of 'less effective'.<br />
|-<br />
|<span style="font-size:150%"> ∫</span><br />
|{{w|integral}}<br />
|Could be used in the manner of a shepherd's crook, or as a {{w|Bill (weapon)|billhook}}. Could be used as a {{w|spear thrower}}, combined with ⋅ or ⇀.<br />
|-<br />
|<span style="font-size:150%"> →</span><br />
|Implies; X→Y means that if X is true, then Y is also true<br />
|Danish is brandishing this symbol against Ponytail, apparently using it like a spear or other polearm.<br />
|-<br />
|<span style="font-size:150%"> ⊥</span><br />
|{{w|up tack}} or falsum, indicating a false proposition in logic or the bottom element in a partial order<br />
|Used as a {{w|war hammer}} (held by the long stem), the opponent would be struck with either leg of the top of the T. Held by the short legs (like a wishbone), could be used as a two handed sword.<br />
(If tipped with a knapped stone head, it could become a {{w|Folsom point|falsum point}}.)<br />
|-<br />
|<span style="font-size:150%"> ⇀</span><br />
|{{w|Vector notation}}<br />
|Could be used as a single-barbed spear. It is unclear why this is listed as less useful than the 'implies' arrow.<br />
|-<br />
|<span style="font-size:150%"> ––</span><br />
|{{w|Fraction#Vocabulary|Fraction bar}} (division) or {{w|Overline#Math_and_science|overline}} (complex conjugate or mean).<br />
|Hairy is brandishing this symbol against Black Hat. The single shaft would allow it to be used in the manner of a {{w|quarterstaff}}, {{w|bō}}, or other {{w|stick-fighting}} weapon. Of the symbols shown in the comic, Randall considers this one the most useful in a fight, presumably because of its greater reach than the vector arrow and its simplicity compared to the radix root symbol.<br />
|-<br />
|<span style="font-size:200%"> 𝄞</span><br />
|{{w|Treble clef}}<br />
|Mentioned in the title text; this is not a mathematical symbol, but a musical symbol. The treble clef is a much more complicated symbol than those used in mathematics, hence the musician's "confidence" in his weapon. The curve at the bottom could be used as a hook, the upper curl could be used as a blunt weapon, and the tight curl of the center would serve as a better defensive shield than theta.<br />
|}<br />
<br />
A straight line is farthest to the "more dangerous" side, which could possibly be a reference to the dangers posed by lines in "Flatland", because their infinitely-sharp endpoints could be difficult to see (particularly their rear end, which does not contain a gleaming eye as their front end does) and would fatally pierce whoever they chose to stab. However, taking a more literal view of the drawings, the straight line does not appear to be any thicker or thinner, or pointier, than any of the other lines. <br />
<br />
The title text refers to a {{w|Treble clef}}, which is not a mathematical symbol but rather a {{w|List of musical symbols|musical symbol}}. The note of concern in the text suggests musical symbols may be viewed in such fights as exotic or especially dangerous.<br />
<br />
==Notes==<br />
<references /><br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
[Heading]<br />
<br />
Mathematical Symbols<br />
<br />
[Subheading]<br />
<br />
by how useful they would be in a fight<br />
<br />
<br />
more useful<br />
<br />
<span style="font-size:150%">⟶</span><br />
<br />
<span style="font-size:150%"> ℝ ∅ > ∝ π + Ψ ~ ⇒ ⋅ Γ √ ∮ ∫ ⇀</span><br />
<br />
<span style="font-size:150%"> θ ∞ ∪ ∈ ∀ ∂ ≠ # Δ ζ ℵ ''ρ'' → ⊥ ––</span><br />
<br />
[Below the (number?) line, eight characters fight each other, using some of the symbols mentioned above as weapons.]<br />
<br />
[The characters hold more "useful" weapons from left to right, correlating with the chart.]<br />
<br />
<br />
<br />
[Megan is awkwardly handling a giant "ℝ".]<br />
<br />
[White Hat is holding a "θ" with both hands, as a shield.]<br />
<br />
[Cueball is holding an "∈" in both hands, with its "tines" pointed towards Blondie, who is swatting at him with a "#".]<br />
<br />
[Ponytail is leaping at Danish, swinging a "''ρ''" like an axe, while Danish is leaning back and thrusting a "→" back at her.]<br />
<br />
[Black Hat is swinging a long "√" like a polearm at Hairy, who is holding a long "⎯" defensively.]<br />
<br />
<br />
-<br />
List of symbols from left to right (by rightmost edge): <br />
<br />
<span style="font-size:150%"> ℝ θ ∅ ∞ > ∪ ∝ ∈ ∀ π ∂ + ≠ Ψ # ~ △ ζ ⇒ ⋅ ℵ Γ ''ρ'' √ → ∮ ∫ ⊥ ⇀ ––</span><br />
<br />
<br />
Note: Where two symbols had similar right-most edges, the overlay grid on an ASUS pro-art display was used to decide which one went further right. <br />
<br />
{{comic discussion}}<br />
[[Category:Math]]<br />
[[Category:Music]]<br />
[[Category:Charts]]<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Comics featuring Danish]]<br />
[[Category:Comics featuring White Hat]]<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Blondie]]<br />
[[Category:Comics featuring Ponytail]]<br />
[[Category:Comics featuring Black Hat]]<br />
[[Category:Comics featuring Hairy]]</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=Talk:2343:_Mathematical_Symbol_Fight&diff=195808Talk:2343: Mathematical Symbol Fight2020-08-09T21:43:22Z<p>172.69.33.223: respond</p>
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<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
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Can I get aleph-null aleph-shaped throwing stars? [[User:LunarNapolean|LunarNapolean]] ([[User talk:LunarNapolean|talk]]) 20:18, 7 August 2020 (UTC)<br />
<br />
Apologies to whoever added the "citation needed" that I stepped on. -- brad<br />
<br />
That zeta looks conspicuously bad. I wonder if this comic will get a cleaned-up version uploaded. [[Special:Contributions/108.162.237.16|108.162.237.16]] 20:51, 7 August 2020 (UTC)<br />
<br />
[[Megan]] usually has shoulder-length hair, so the person being attacked by Ponytail is probably not Megan... except in so far as all brunettes in this comic are called 'Megan'. [[User:LtPowers|LtPowers]] ([[User talk:LtPowers|talk]]) 20:53, 7 August 2020 (UTC)<br />
:Is one of them [[Danish]]? And one of them Megan? [[Special:Contributions/172.69.33.121|172.69.33.121]] 22:49, 7 August 2020 (UTC)<br />
<br />
I think Randall is underestimating the weapon utility of psi. There's a real-world martial arts [https://en.wikipedia.org/wiki/Sai_(weapon) weapon] that looks somewhat like it.[[Special:Contributions/172.69.68.197|172.69.68.197]] 22:04, 7 August 2020 (UTC)<br />
:I think he’s also seriously underestimating the value of keeping your fingers attached to your hand. Swords have guards for a reason. I’d pick the contour integral over anything else there.<br />
<br />
Considering the title text, a bass clef looks pretty formidable, close to a bat'leth. [[User:Nutster|Nutster]] ([[User talk:Nutster|talk]]) 00:31, 8 August 2020 (UTC)<br />
:Yes, but the treble clef is the one in the title text, and that’s nothing like a Klingon {{w|bat'leth}}. I removed the comment from the table. [[User:Adam1729|Adam1729]] ([[User talk:Adam1729|talk]]) 02:09, 8 August 2020 (UTC)<br />
<br />
These “weapons” seem strangely appropriate for xkcd’s stick figures... -cpl<br />
: Agreed :)<br />
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Are we sure White Hat is holding empty set? There don't appear to be points extending outside the circle in which case I think he's actually holding Theta -jc<br />
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Can I use the LaTeX mathwitch? [[Special:Contributions/141.101.98.26|141.101.98.26]] 10:03, 8 August 2020 (UTC)<br />
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First time editor here,hope I get the notation right! Question on the pi link to wikipedia: I put in the double link to the main page and the disambiguation because unfortunately https://en.wikipedia.org/wiki/Pi_(disambiguation)#Mathematics doesn't include the mathematical constant definition (though it is listed at the top of the page). Thoughts? [[User:Alan g|Alan g]] ([[User talk:Alan g|talk]]) 10:38, 8 August 2020 (UTC)<br />
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I think that’s the is proportional to” symbol rather than just alpha. They are similar but have different Unicode symbols. Thoughts?--[[Special:Contributions/141.101.98.222|141.101.98.222]] 12:01, 8 August 2020 (UTC)<br />
:You're definitely correct. (They don't even look that similar...) It's the direct proportion symbol, not the symbol for Alpha. <br />
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 18:03, 8 August 2020 (UTC)<br />
I don't think → is "implies", particularly as we've had ⇒ earlier. → is often used for "maps to", as in f: x → f(x) [[Special:Contributions/141.101.107.166|141.101.107.166]] 19:24, 8 August 2020 (UTC)<br />
:→ and ⇒ often mean two different kinds of "implies". The single arrow is for the boolean operator that takes in two truth values and outputs a truth value. The double one is for "things on the left justify/prove things on the right", in somewhat of a metalanguage. Here's an example of two different ways of saying Modus Ponens with the operators: ((p→q) ∧p)→q vs p→q,p⇒q [[User:Alan g|Alan g]] ([[User talk:Alan g|talk]]) 03:52, 9 August 2020 (UTC)<br />
Are we sure that is the multiplication sign (center dot)? The placement makes it seem more a decimal point. [[Special:Contributions/162.158.123.47|162.158.123.47]] 21:51, 8 August 2020 (UTC)<br />
:Confusingly, math conventions in some countries use a low dot for multiplication, though it's not as common as it used to be. That's in addition to all the other things that bare dots can represent in math. Personally I can't "see" any particular set of semantics for that symbol, I just see a dot. [[Special:Contributions/162.158.186.136|162.158.186.136]] 22:51, 8 August 2020 (UTC)<br />
We see a greater-than, but no less-than. Where would that appear? I think >≠<, in fact ><<, if wielded properly. Though if thrown, either/both could be a multi-use projectile... [[Special:Contributions/141.101.98.96|141.101.98.96]] 09:08, 9 August 2020 (UTC)<br />
: Took me a little bit to figure out what you meant, but I think it hasn't been clarified which side is the point or sharp side, so until that is clarified "<"=">"<br />
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Anyone else think the title text is hinting at a pun? "I got scared because his weapon looked like treble" sort of thing?<br />
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Where is the opening parenthesis? [[Special:Contributions/172.69.33.223|172.69.33.223]] 21:43, 9 August 2020 (UTC)</div>172.69.33.223https://www.explainxkcd.com/wiki/index.php?title=2342:_Exposure_Notification&diff=1955912342: Exposure Notification2020-08-06T03:11:29Z<p>172.69.33.223: /* Transcript */ this isn't in the comic</p>
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<div>{{comic<br />
| number = 2342<br />
| date = August 5, 2020<br />
| title = Exposure Notification<br />
| image = exposure_notification.png<br />
| titletext = I don't see why everyone is so hungry for BAD news, but fine, I'll give in to feedback and add a dark mode.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a BOT THAT RECENTLY HAD CLOSE CONTACT WITH SOMEONE WHO HAS NOT TESTED POSITIVE FOR COVID. Do NOT delete this tag too soon.}}<br />
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During the coronavirus pandemic, several apps were developed to implement {{w|digital contact tracing}} by using one's location along with the location of others, or locationless device proximity detection, to notify someone if they had been potentially exposed to COVID-19. In this comic, a different type of app has been developed. Instead of notifying someone if they have been exposed to someone with COVID-19, the app produces notifications if they have been exposed to someone who has '''not''' tested positive. This is much less useful because it is not possible to tell whether anyone has actually been near anyone who was infected, but rather annoys the user with excessive notifications.[[File:GNOME Shell, GNOME Clocks, Evince, gThumb, GNOME Files at version 3.30 (2018-09) in Dark theme.png|thumb|right|The GNOME desktop environment in dark mode]]<br />
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{{w|Light-on-dark color scheme| Dark mode}} is a common feature in apps which allows users the options to have a darker user interface. The title text, however, refers to dark mode not in the sense of the color scheme but rather that receiving notifications bearing the bad news that you have been exposed to COVID-19 is "dark." Because nobody likes his current app, Randall decides to give in and create a dark mode, which would make his app much more desirable for users.<br />
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Randall has published similar "useless useful apps" in [[937: TornadoGuard]] (a tornado-alert app that has lots of great features, except it doesn't actually alert the user about tornadoes) and [[2236|2236: Is it Christmas?]] (a web page that correctly identifies most days as "not Christmas", but then fails to identify Christmas Day as Christmas, for a >99% "accuracy").<br />
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==Transcript==<br />
:[Cueball standing, holding out his chiming smartphone to review alerts it has received.]<br />
<br />
:Alert 1:43 PM<br />
:'''Good news:''' You recently had close contact with someone who has not tested positive for COVID.<br />
:Alert 1:38 PM<br />
:'''Good news:''' You recently had close contact with someone who has not tested positive for COVID.<br />
:Alert 1:36 PM<br />
:'''Good news:''' You recently had close contact with someone who has not tested positive for COVID.<br />
:Alert 1:31 PM<br />
:'''Good news:''' You recently had close contact with someone who has not tested positive for COVID.<br />
:[Caption below the panel:]<br />
:No one likes my new COVID exposure notification app.<br />
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{{comic discussion}}<br />
[[Category:COVID-19]]<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Smartphones]]</div>172.69.33.223