https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&feedformat=atom&user=172.70.211.36 2026-04-15T03:14:09Z User contributions MediaWiki 1.30.0 https://www.explainxkcd.com/wiki/index.php?title=2648:_Chemicals&diff=289572 2022-07-20T23:35:25Z

<p>172.70.211.36: /* Explanation */ traditional to link characters</p> <hr /> <div>{{comic<br /> | number = 2648<br /> | date = July 20, 2022<br /> | title = Chemicals<br /> | image = chemicals.png<br /> | titletext = It's hard to believe, but lots of kids these days ONLY know how to buy prepackaged molecules.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by BIG MOLECULE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> In this comic, [[Megan]] mentions that you can find the chemical formulas for chemicals online, and that they spend a lot on fancy chemicals. Bizarrely, she suggests that &quot;they can assemble&quot; their chemicals themselves. When Megan says this she is holding a sheet that contains the chemical formula for {{w|nitrobenzene}}. This is impossible without expensive {{w|chemical synthesis}} equipment.[https://www.youtube.com/watch?v=5QwW2owNWgc] This formula also adds to the humor because nitrobenzene is extremely toxic and the synthesis of nitrobenzene is highly exothermic and thus extremely dangerous.[https://www.icheme.org/media/10339/xiii-paper-36.pdf] Such issues answer [[Cueball]]'s question as to why more people don't manufacture their own chemicals. Big Molecule is a reference to [[2130: Industry Nicknames|Big Pharma]], a name for the pharmaceutical industry.<br /> <br /> The title text refers to the fact that many people believe that &quot;kids these days&quot; don't do enough work or are spoiled. Randall has expressed that he dislikes statements like these in [[2165: Millennials|previous comics]].<br /> <br /> Today's comic premise may have been prompted by recent news that [https://english.elpais.com/science-tech/2022-07-15/for-the-first-time-in-history-we-can-modify-atomic-bonds-in-a-single-molecule.html scientists have found a way to assemble and change atoms in a single molecule] by modifying its bonds. Or it may also be completely unrelated.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Megan and Cueball standing next to each other. Megan has her palms raised.]<br /> :Megan: You know how our company spends a lot on expensive chemicals?<br /> :Cueball: Yeah?<br /> <br /> :[Megan holding up a piece of paper with a chemical formula on it, as well as some computation for the number of atoms needed]<br /> :Megan: Well, I just learned you can look up all of the formulas online!<br /> :Megan: We can just buy the atoms in bulk and assemble them here! <br /> :[The paper reads as follows. The illegible items appear to be prices.]<br /> :C&lt;sub&gt;6&lt;/sub&gt;H&lt;sub&gt;5&lt;/sub&gt;NO&lt;sub&gt;2&lt;/sub&gt;<br /> :Carbon 6 $[illegible]<br /> :Hydrogen 5 $[illegible]<br /> :Nitrogen 1 $[illegible]<br /> :&lt;u&gt;Oxygen 2 $[illegible]&lt;/u&gt;<br /> :Total 14 $[illegible]<br /> <br /> :[Cueball still standing. Megan walking off-panel to the right]<br /> :Cueball: I wonder why more places don't do that.<br /> :Megan: People have no idea they're getting ripped off by Big Molecule!<br /> <br /> {{comic discussion}}<br /> [[Category:Comics featuring Cueball]]<br /> [[Category:Comics featuring Megan]]<br /> [[Category:Chemistry]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2648:_Chemicals&diff=289571 2022-07-20T23:34:24Z

<p>172.70.211.36: /* Explanation */ copyedit</p> <hr /> <div>{{comic<br /> | number = 2648<br /> | date = July 20, 2022<br /> | title = Chemicals<br /> | image = chemicals.png<br /> | titletext = It's hard to believe, but lots of kids these days ONLY know how to buy prepackaged molecules.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by BIG MOLECULE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> In this comic, Megan mentions that you can find the chemical formulas for chemicals online, and that they spend a lot on fancy chemicals. Bizarrely, she suggests that &quot;they can assemble&quot; their chemicals themselves. When Megan says this she is holding a sheet that contains the chemical formula for {{w|nitrobenzene}}. This is impossible without expensive {{w|chemical synthesis}} equipment.[https://www.youtube.com/watch?v=5QwW2owNWgc] This formula also adds to the humor because nitrobenzene is extremely toxic and the synthesis of nitrobenzene is highly exothermic and thus extremely dangerous.[https://www.icheme.org/media/10339/xiii-paper-36.pdf] Such issues answer Cueball's question as to why more people don't manufacture their own chemicals. Big Molecule is a reference to [[2130: Industry Nicknames|Big Pharma]], a name for the pharmaceutical industry.<br /> <br /> The title text refers to the fact that many people believe that &quot;kids these days&quot; don't do enough work or are spoiled. Randall has expressed that he dislikes statements like these in [[2165: Millennials|previous comics]].<br /> <br /> Today's comic premise may have been prompted by recent news that [https://english.elpais.com/science-tech/2022-07-15/for-the-first-time-in-history-we-can-modify-atomic-bonds-in-a-single-molecule.html scientists have found a way to assemble and change atoms in a single molecule] by modifying its bonds. Or it may also be completely unrelated.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Megan and Cueball standing next to each other. Megan has her palms raised.]<br /> :Megan: You know how our company spends a lot on expensive chemicals?<br /> :Cueball: Yeah?<br /> <br /> :[Megan holding up a piece of paper with a chemical formula on it, as well as some computation for the number of atoms needed]<br /> :Megan: Well, I just learned you can look up all of the formulas online!<br /> :Megan: We can just buy the atoms in bulk and assemble them here! <br /> :[The paper reads as follows. The illegible items appear to be prices.]<br /> :C&lt;sub&gt;6&lt;/sub&gt;H&lt;sub&gt;5&lt;/sub&gt;NO&lt;sub&gt;2&lt;/sub&gt;<br /> :Carbon 6 $[illegible]<br /> :Hydrogen 5 $[illegible]<br /> :Nitrogen 1 $[illegible]<br /> :&lt;u&gt;Oxygen 2 $[illegible]&lt;/u&gt;<br /> :Total 14 $[illegible]<br /> <br /> :[Cueball still standing. Megan walking off-panel to the right]<br /> :Cueball: I wonder why more places don't do that.<br /> :Megan: People have no idea they're getting ripped off by Big Molecule!<br /> <br /> {{comic discussion}}<br /> [[Category:Comics featuring Cueball]]<br /> [[Category:Comics featuring Megan]]<br /> [[Category:Chemistry]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2647:_Capri_Suns&diff=289102 2022-07-19T15:41:22Z

<p>172.70.211.36: /* Explanation */ copyedit</p> <hr /> <div>{{comic<br /> | number = 2647<br /> | date = July 18, 2022<br /> | title = Capri Suns<br /> | image = capri_suns.png<br /> | titletext = [As security is dragging me away] &quot;Come on, at least I didn't make the mistake in the other direction!&quot;<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a DISGUSTED NURSE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> [[Cueball]] has been impersonating a doctor at a hospital. But his attempt to fool the staff (including [[Megan]] and [[:Category:Doctor Ponytail|Doctor Ponytail]]) fails when he mistakes a saline bag for a Capri Sun juice.<br /> <br /> {{w|Capri Sun}} is a fruit juice concentrate beverage that comes in soft rectangular mylar bags with a small seal near the top, to be pierced with an included straw so as to sip the drink. {{w|Saline (medicine)|Saline}} bags, used in hospitals and other medical settings, are also soft and rectangular, with an {{w|Intravenous therapy#Medical uses|intravenous}} (I.V.) drip connection about the same size as such straws, and usually contain a 0.9% sodium chloride (table salt) solution in sterile water so they are salty enough to be {{w|Tonicity#Isotonicity|isotonic}} with blood. Capri Sun is mostly sugar water, and only 0.00008% salt,[https://www.aqua-calc.com/calculate/food-volume-to-weight/substance/capri-blank-sun-coma-and-blank-fruit-blank-juice-blank-drink] so it tastes sweet instead.<br /> <br /> Almost everyone would be very unlikely to accidentally mistake saline bags for Capri Sun, especially a medical doctor.{{citation needed}} Cueball's attempt to impersonate a doctor derails when hospital staff notice he made such an absurdly unlikely and therefore humorous error.<br /> <br /> The title text makes it clear that Cueball is being removed from the hospital by security personnel. While they are dragging him out, he tries to point out that drinking saline is better than putting Capri Sun into a patient's I.V. drip, as it would endanger the patient.[https://www.bbc.com/news/world-asia-china-47623816] He is trying to claim this mitigates the severity of his incompetence. The security personnel apprehending him are unlikely to be persuaded, as impersonating hospital staff is a serious offense with dangerous risks and severe consequences. In California, the unlicensed practice of medicine can result in a $10,000 fine, a year in prison, or both.[https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=BPC&amp;sectionNum=2052.]<br /> <br /> The comic arguably continues [[451: Impostor]] and [[699: Trimester]].<br /> <br /> ==Transcript==<br /> :[Cueball, wearing a lab coat, is drinking out of a straw inserted into an IV drip bag that is labelled &quot;saline&quot; (on the 2x image; it is rendered unreadable on the standard resolution version, just like the rest of the label's squiggles). Cueball is surrounded by hospital staff. To the left is Megan with a white hat, she is holding a clipboard, with a paper with unreadable text. To his right is Dr. Ponytail holding a rolled up paper under one arm and to the right of her a man with a similar hat as Megan. They are all looking at Cueball.]<br /> :Cueball: You know, these Capri Suns are good, but they're ''really'' salty.<br /> <br /> :[Caption below the panel:]<br /> :I think the hospital may be starting to realize that I'm not actually a doctor.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Comics featuring Megan]]<br /> [[Category:Comics featuring Cueball]]<br /> [[Category:Doctor Ponytail]]<br /> [[Category:Characters with hats]]<br /> [[Category:Medicine]]<br /> [[Category:Food]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2647:_Capri_Suns&diff=289101 2022-07-19T15:38:46Z

<p>172.70.211.36: /* Explanation */ tighten</p> <hr /> <div>{{comic<br /> | number = 2647<br /> | date = July 18, 2022<br /> | title = Capri Suns<br /> | image = capri_suns.png<br /> | titletext = [As security is dragging me away] &quot;Come on, at least I didn't make the mistake in the other direction!&quot;<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a DISGUSTED NURSE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> [[Cueball]] has been impersonating a doctor at a hospital. But his attempt to fool the staff (including [[Megan]] and [[:Category:Doctor Ponytail|Doctor Ponytail]]) fails when he mistakes a saline bag for a Capri Sun juice.<br /> <br /> {{w|Capri Sun}} is a fruit juice concentrate beverage that comes in soft rectangular mylar bags with a small seal near the top, to be pierced with an included straw so as to sip the drink. {{w|Saline (medicine)|Saline}} bags, used in hospitals and other medical settings, are also soft and rectangular, with an {{w|Intravenous therapy#Medical uses|intravenous}} (I.V.) drip connection about the same size as such straws, and usually contain a 0.9% sodium chloride (table salt) solution in sterile water so they are salty enough to be {{w|Tonicity#Isotonicity|isotonic}} with blood. Capri Sun is mostly sugar water, and only 0.00008% salt,[https://www.aqua-calc.com/calculate/food-volume-to-weight/substance/capri-blank-sun-coma-and-blank-fruit-blank-juice-blank-drink] so it tastes sweet instead.<br /> <br /> Almost everyone would be very unlikely to accidentally mistake saline bags for Capri Sun, especially a medical doctor.{{citation needed}} Cueball's attempt to impersonate a doctor was derailed when hospital staff noticed that he had made such an absurdly unlikely and therefore humorous mistake.<br /> <br /> The title text makes it clear that Cueball is being removed from the hospital by security personnel. While they are dragging him out, he tries to point out that drinking saline is better than putting Capri Sun into a patient's I.V. drip, as it would endanger the patient.[https://www.bbc.com/news/world-asia-china-47623816] He is trying to claim this mitigates the severity of his incompetence. The security personnel apprehending him are unlikely to be persuaded, as impersonating hospital staff is a serious offense with dangerous risks and severe consequences. In California, the unlicensed practice of medicine can result in a $10,000 fine, a year in prison, or both.[https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=BPC&amp;sectionNum=2052.]<br /> <br /> The comic arguably continues [[451: Impostor]] and [[699: Trimester]].<br /> <br /> ==Transcript==<br /> :[Cueball, wearing a lab coat, is drinking out of a straw inserted into an IV drip bag that is labelled &quot;saline&quot; (on the 2x image; it is rendered unreadable on the standard resolution version, just like the rest of the label's squiggles). Cueball is surrounded by hospital staff. To the left is Megan with a white hat, she is holding a clipboard, with a paper with unreadable text. To his right is Dr. Ponytail holding a rolled up paper under one arm and to the right of her a man with a similar hat as Megan. They are all looking at Cueball.]<br /> :Cueball: You know, these Capri Suns are good, but they're ''really'' salty.<br /> <br /> :[Caption below the panel:]<br /> :I think the hospital may be starting to realize that I'm not actually a doctor.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Comics featuring Megan]]<br /> [[Category:Comics featuring Cueball]]<br /> [[Category:Doctor Ponytail]]<br /> [[Category:Characters with hats]]<br /> [[Category:Medicine]]<br /> [[Category:Food]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2647:_Capri_Suns&diff=289065 2022-07-19T11:53:04Z

<p>172.70.211.36: /* Explanation */ copyedit</p> <hr /> <div>{{comic<br /> | number = 2647<br /> | date = July 18, 2022<br /> | title = Capri Suns<br /> | image = capri_suns.png<br /> | titletext = [As security is dragging me away] &quot;Come on, at least I didn't make the mistake in the other direction!&quot;<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a DISGUSTED NURSE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> {{w|Capri Sun}} is a fruit juice concentrate drink that comes in soft rectangular mylar bags with a small seal near the top, to be pierced with an included straw so as to sip the beverage. {{w|Saline (medicine)|Saline}} bags, used in hospitals and other medical settings, are also soft and rectangular, with an {{w|intravenous}} (IV) drip connection, and usually contain a 0.9% sodium chloride (table salt) solution in sterile water so as to be {{w|isotonic}} to blood. Capri Sun is mostly sugar water, and only 0.00008% salt,[https://www.aqua-calc.com/calculate/food-volume-to-weight/substance/capri-blank-sun-coma-and-blank-fruit-blank-juice-blank-drink this site] so tastes sweet instead of salty like saline.<br /> <br /> The title text is pointing out that mistakenly drinking saline out of the bag is better than putting Capri Sun into patient's IV drip in place of saline, as it would endanger the patient.[https://www.bbc.com/news/world-asia-china-47623816] The speaker is trying to claim this mitigates the severity of their incompetence. The security personnel mentioned in the title text are likely not persuaded, as impersonating hospital staff is a serious offense with dangerous risks and severe consequences.<br /> <br /> The comic arguably functions as a continuation of [[451: Impostor]] and [[699: Trimester]].<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Created by SOMEONE W.H.O. IS NOT A DOCTOR - Do NOT delete this tag too soon.}}<br /> :[Cueball, wearing a lab coat, is drinking out of a straw inserted into an IV drip bag that is labelled &quot;saline&quot;. The figure is surrounded by doctors and hospital staff who appear to include Ponytail and Megan, all of whom are looking at Cueball.]<br /> :Cueball: You know, these Capri Suns are good, but they're ''really'' salty.<br /> <br /> :[Caption below panel:]<br /> :I think the hospital may be starting to realize that I'm not actually a doctor.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Comics featuring Cueball]]<br /> [[Category:Comics featuring Ponytail]]<br /> [[Category:Comics featuring Megan]]<br /> [[Category:Multiple Cueballs]]<br /> [[Category:Doctor Ponytail]]<br /> [[Category:Medicine]]<br /> [[Category:Food]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2647:_Capri_Suns&diff=289064 2022-07-19T11:51:56Z

<p>172.70.211.36: /* Explanation */ ce</p> <hr /> <div>{{comic<br /> | number = 2647<br /> | date = July 18, 2022<br /> | title = Capri Suns<br /> | image = capri_suns.png<br /> | titletext = [As security is dragging me away] &quot;Come on, at least I didn't make the mistake in the other direction!&quot;<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a DISGUSTED NURSE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> {{w|Capri Sun}} is a fruit juice concentrate drink that comes in a soft rectangular mylar bag with a sealed to be pierced with an included straw to sip the beverage. {{w|Saline (medicine)|Saline}} bags, used in hospitals and other medical settings, are also soft and rectangular, with an {{w|intravenous}} (IV) drip connection, and usually contain a 0.9% sodium chloride (table salt) solution in sterile water so as to be {{w|isotonic}} to blood. Capri Sun is mostly sugar water, and only 0.00008% salt,[https://www.aqua-calc.com/calculate/food-volume-to-weight/substance/capri-blank-sun-coma-and-blank-fruit-blank-juice-blank-drink this site] so tastes sweet instead of salty like saline.<br /> <br /> The title text is pointing out that mistakenly drinking saline out of the bag is better than putting Capri Sun into patient's IV drip in place of saline, as it would endanger the patient.[https://www.bbc.com/news/world-asia-china-47623816] The speaker is trying to claim this mitigates the severity of their incompetence. The security personnel mentioned in the title text are likely not persuaded, as impersonating hospital staff is a serious offense with dangerous risks and severe consequences.<br /> <br /> The comic arguably functions as a continuation of [[451: Impostor]] and [[699: Trimester]].<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Created by SOMEONE W.H.O. IS NOT A DOCTOR - Do NOT delete this tag too soon.}}<br /> :[Cueball, wearing a lab coat, is drinking out of a straw inserted into an IV drip bag that is labelled &quot;saline&quot;. The figure is surrounded by doctors and hospital staff who appear to include Ponytail and Megan, all of whom are looking at Cueball.]<br /> :Cueball: You know, these Capri Suns are good, but they're ''really'' salty.<br /> <br /> :[Caption below panel:]<br /> :I think the hospital may be starting to realize that I'm not actually a doctor.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Comics featuring Cueball]]<br /> [[Category:Comics featuring Ponytail]]<br /> [[Category:Comics featuring Megan]]<br /> [[Category:Multiple Cueballs]]<br /> [[Category:Doctor Ponytail]]<br /> [[Category:Medicine]]<br /> [[Category:Food]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2647:_Capri_Suns&diff=289063 2022-07-19T11:49:30Z

<p>172.70.211.36: /* Explanation */ copyedit</p> <hr /> <div>{{comic<br /> | number = 2647<br /> | date = July 18, 2022<br /> | title = Capri Suns<br /> | image = capri_suns.png<br /> | titletext = [As security is dragging me away] &quot;Come on, at least I didn't make the mistake in the other direction!&quot;<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a DISGUSTED NURSE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> {{w|Capri Sun}} is a fruit juice concentrate drink that comes in a soft rectangular mylar bag with a sealed to be pierced with an included straw to sip the beverage. {{w|Saline (medicine)|Saline bags}}, used in hospitals and other medical settings, are also soft rectangular bags with an {{w|intravenous}} (IV) drip connection, and usually contain a 0.9% sodium chloride (table salt) solution in sterile water so as to be {{w|isotonic}} to blood. Capri Sun is mostly sugar water, and only 0.00008% salt,[https://www.aqua-calc.com/calculate/food-volume-to-weight/substance/capri-blank-sun-coma-and-blank-fruit-blank-juice-blank-drink this site] so taste sweet instead of salty.<br /> <br /> The title text is pointing out that mistakenly drinking saline out of the bag is better than putting Capri Sun into patient's IV drip in place of saline, as it would endanger the patient.[https://www.bbc.com/news/world-asia-china-47623816] The speaker is trying to claim this mitigates the severity of their incompetence. The security personnel mentioned in the title text are likely not persuaded, as impersonating hospital staff is a serious offense with dangerous risks and severe consequences.<br /> <br /> The comic arguably functions as a continuation of [[451: Impostor]] and [[699: Trimester]].<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Created by SOMEONE W.H.O. IS NOT A DOCTOR - Do NOT delete this tag too soon.}}<br /> :[Cueball, wearing a lab coat, is drinking out of a straw inserted into an IV drip bag that is labelled &quot;saline&quot;. The figure is surrounded by doctors and hospital staff who appear to include Ponytail and Megan, all of whom are looking at Cueball.]<br /> :Cueball: You know, these Capri Suns are good, but they're ''really'' salty.<br /> <br /> :[Caption below panel:]<br /> :I think the hospital may be starting to realize that I'm not actually a doctor.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Comics featuring Cueball]]<br /> [[Category:Comics featuring Ponytail]]<br /> [[Category:Comics featuring Megan]]<br /> [[Category:Multiple Cueballs]]<br /> [[Category:Doctor Ponytail]]<br /> [[Category:Medicine]]<br /> [[Category:Food]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2646:_Minkowski_Space&diff=288903 2022-07-16T04:21:16Z

<p>172.70.211.36: /* Explanation */ section break for avoiding edit conflicts</p> <hr /> <div>{{comic<br /> | number = 2646<br /> | date = July 15, 2022<br /> | title = Minkowski Space<br /> | image = minkowski_space.png<br /> | titletext = My liege, we were able to follow the ship into Minkowski space, but now they've jumped to Hilbert space and they could honestly be anywhere.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by A RELATIVISTIC QUANTUM STATE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> A spaceship is being pursued by an enemy ship. Much like in [[2577: Sea Chase]], it attempts to escape by changing the nature of the space. In this case, it goes into {{w|Minkowski space}}, a mathematical formulation of three dimensional space combined with the dimension of time to form a {{w|manifold}} originally intended to describe {{w|electromagnetism}} in terms of {{w|special relativity}}, and which is also used in {{w|general relativity}}.<br /> <br /> Minkowski space is no different than ordinary spatiotemporal physical reality, so the idea of traveling from regular space into Minkowski space is meaningless, providing the humor of the comic's absurdist joke. The visual depiction of the spaceships skewed diagonally is based on graphical {{w|Minkowski diagram}} representation of objects in Minkowski space, where the {{w|world line}} of matter is bounded inside its diagonal {{w|light cone}}. The mention of distance depending on the observer's {{w|frame of reference}} refers to distances changing when measured in different inertial frames of reference, a concept called the {{w|relativity of simultaneity}}.<br /> <br /> The title text implies hiding in {{w|Hilbert space}} is much easier. This is because Hilbert spaces can have an infinite number of dimensions, and thus are much more complicated than four-dimensional Minkowski space. However, Hilbert space is used to describe mathematical objects such as functions of various parameters and complexity, not physical spatiotemporal reality, so it is very unusual for a physical object to be represented in Hilbert space. The reference to Hilbert space could also refer to the {{w|Uncertainty principle}}, as quantum states can be represented as vectors in a Hilbert space.<br /> <br /> === Apparent distance ===<br /> <br /> Whether the two spaceships are getting closer to each other does not depend on frame of reference if both the ships are moving at constant velocity.<br /> Though if they are accelerating then depending on frame of reference they may be getting further apart or they may be getting closer.<br /> If the ship giving chase has higher velocity than the ship being chased but ship being chased is accelerating faster then from the perspective of ship being chased the other ship is getting closer to it . While from perspective of something a few light years away which is moving towards both of the ships the ship being chased is getting more distant from the other ship.<br /> <br /> <br /> This is because from perspective of something a few light years away which is moving towards the ships the ship being chased has already accelrated and is faster from the other ship so the distance between them is increasing.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> :{A spaceship is being pursued.}<br /> :Voice 1: The enemy ship is right behind us! Prepare to jump to Minowski space on my mark.<br /> <br /> :Voice 1: Three... two... one... MARK!<br /> :SFX: Click<br /> <br /> :{The panel distorts.}<br /> <br /> :{The panel distorts further.}<br /> :Voice 1: Are they still getting closer?<br /> :Voice 2: I can't tell.<br /> :Voice 3: I think it depends on your frame of reference.<br /> <br /> {{comic discussion}}</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2646:_Minkowski_Space&diff=288901 2022-07-16T04:19:11Z

<p>172.70.211.36: Please be careful not to undo others edits when e.g. recovering from edit confkicts</p> <hr /> <div>{{comic<br /> | number = 2646<br /> | date = July 15, 2022<br /> | title = Minkowski Space<br /> | image = minkowski_space.png<br /> | titletext = My liege, we were able to follow the ship into Minkowski space, but now they've jumped to Hilbert space and they could honestly be anywhere.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by A RELATIVISTIC QUANTUM STATE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> A spaceship is being pursued by an enemy ship. Much like in [[2577: Sea Chase]], it attempts to escape by changing the nature of the space. In this case, it goes into {{w|Minkowski space}}, a mathematical formulation of three dimensional space combined with the dimension of time to form a {{w|manifold}} originally intended to describe {{w|electromagnetism}} in terms of {{w|special relativity}}, and which is also used in {{w|general relativity}}.<br /> <br /> Minkowski space is no different than ordinary spatiotemporal physical reality, so the idea of traveling from regular space into Minkowski space is meaningless, providing the humor of the comic's absurdist joke. The visual depiction of the spaceships skewed diagonally is based on graphical {{w|Minkowski diagram}} representation of objects in Minkowski space, where the {{w|world line}} of matter is bounded inside its diagonal {{w|light cone}}. The mention of distance depending on the observer's {{w|frame of reference}} refers to distances changing when measured in different inertial frames of reference, a concept called the {{w|relativity of simultaneity}}.<br /> <br /> The title text implies hiding in {{w|Hilbert space}} is much easier. This is because Hilbert spaces can have an infinite number of dimensions, and thus are much more complicated than four-dimensional Minkowski space. However, Hilbert space is used to describe mathematical objects such as functions of various parameters and complexity, not physical spatiotemporal reality, so it is very unusual for a physical object to be represented in Hilbert space. The reference to Hilbert space could also refer to the {{w|Uncertainty principle}}, as quantum states can be represented as vectors in a Hilbert space.<br /> <br /> <br /> Whether the two spaceships are getting closer to each other does not depend on frame of reference if both the ships are moving at constant velocity.<br /> Though if they are accelerating then depending on frame of reference they may be getting further apart or they may be getting closer.<br /> If the ship giving chase has higher velocity than the ship being chased but ship being chased is accelerating faster then from the perspective of ship being chased the other ship is getting closer to it but from perspective of something a few light years away which is moving towards both of the ships the ship being chased is getting more distant from the other ship.<br /> <br /> <br /> This is because from perspective of something a few light years away which is moving towards the ships the ship being chased has already accelrated and is faster from the other ship so the distance between them is increasing.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> :{A spaceship is being pursued.}<br /> :Voice 1: The enemy ship is right behind us! Prepare to jump to Minowski space on my mark.<br /> <br /> :Voice 1: Three... two... one... MARK!<br /> :SFX: Click<br /> <br /> :{The panel distorts.}<br /> <br /> :{The panel distorts further.}<br /> :Voice 1: Are they still getting closer?<br /> :Voice 2: I can't tell.<br /> :Voice 3: I think it depends on your frame of reference.<br /> <br /> {{comic discussion}}</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=Talk:2645:_The_Best_Camera&diff=288863 2022-07-16T00:07:05Z

<p>172.70.211.36: Yep</p> <hr /> <div>&lt;!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--&gt;<br /> Removed the part about L2 being in Earth's umbra. Although this is true, the JWST is not actually ''at'' L2; it revolves around L2, specifically to avoid being in the Earth's umbra (and the moon's) and therefore avoid changes in temperature. [[User:DKMell|DKMell]] ([[User talk:DKMell|talk]]) 17:52, 13 July 2022 (UTC)<br /> <br /> Does anyone know whether they use [https://ds9.si.edu/doc/user/rgb/index.html SAOImageDS9] or [https://docs.astropy.org/en/stable/visualization/rgb.html Astropy] to make full color images? Both are listed under [https://www.stsci.edu/jwst/science-execution/data-analysis-toolbox post-pipeline tools.] General instructions are in [https://arxiv.org/pdf/2001.02618.pdf this paper] but it's not a software tutorial, and it doesn't mention un-redshifting very distant objects like in [https://www.youtube.com/watch?v=sNJR3lenz1I&amp;t=293s Dr. Becky's video] (and which they didn't do completely for the deep field because the lensed galaxies were actually red.) [[Special:Contributions/172.70.206.213|172.70.206.213]] 05:35, 14 July 2022 (UTC)<br /> :Can we use the published image [https://www.stsci.edu/jwst/phase2-public/2736.pdf data] files to produce a {{w|SMACS J0723.3–7327|SMACS 0723}} image with only the far-redshifted, lensed objects? [[Special:Contributions/172.70.211.36|172.70.211.36]] 16:01, 14 July 2022 (UTC)<br /> ::There is a tutorial at https://www.galactic-hunter.com/post/jwst-data by a guy who uses PixInsight, which unlike DS9 and Astropy is commercial (€230) but a anyone can use it free for 45 days. I think the instructions for what you want to do are at https://pixinsight.com/tutorials/PCC/index.html and the data is [https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html?searchQuery=%7B%22service%22%3A%22JWSTFILTERED%22%2C%22inputText%22%3A%5B%7B%22paramName%22%3A%22targname%22%2C%22niceName%22%3A%22targname%22%2C%22values%22%3A%5B%22SMACS%20J0723.3-7327%22%5D%2C%22valString%22%3A%22SMACS%20J0723.3-7327%22%2C%22isDate%22%3Afalse%2C%22facetType%22%3A%22discrete%22%2C%22displayString%22%3A%22SMACS%20J0723.3-7327%22%7D%5D%2C%22position%22%3A%22undefined%2C%20undefined%2C%20undefined%22%2C%22paramsService%22%3A%22Mast.Jwst.Filtered.Miri%22%2C%22title%22%3A%22JWST%3A%20%20Advanced%20Search%201%22%2C%22tooltip%22%3A%22SMACS%20J0723.3-7327%3B%20%22%2C%22columns%22%3A%22*%22%7D here] for SMACS 0723. [[Special:Contributions/172.70.211.36|172.70.211.36]] 00:07, 16 July 2022 (UTC)<br /> <br /> When discussing biosignatures of exoplanets, should we draw the distinction between ozone and water? [[Special:Contributions/162.158.106.113|162.158.106.113]] 11:58, 14 July 2022 (UTC)</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=Talk:2638:_Extended_NFPA_Hazard_Diamond&diff=288837 2022-07-14T16:23:55Z

<p>172.70.211.36: Compromise proposal</p> <hr /> <div>&lt;!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--&gt;<br /> <br /> Are we going to try identifying what material this is? [[Special:Contributions/172.70.82.179|172.70.82.179]] 01:50, 28 June 2022 (UTC)<br /> :first one off the top of my head, aqua regia? [[Special:Contributions/172.70.38.69|172.70.38.69]] 02:46, 28 June 2022 (UTC)Bumpf<br /> ::Doesn't aqua regia score a 0 in reactivity? [[User:N-eh|N-eh]] ([[User talk:N-eh|talk]]) 03:23, 28 June 2022 (UTC)<br /> ::Or maybe Aqua Velva? That would explain the orange square, although maybe it would be a number larger than 1. [[Special:Contributions/172.70.34.171|172.70.34.171]] 22:49, 28 June 2022 (UTC)<br /> :My guess would be something radioactive, like uranium or plutonium. [[User:Clam|Clam]] ([[User talk:Clam|talk]]) 03:29, 28 June 2022 (UTC)<br /> ::There are very, very few Health 4 / Fire 0 / Instability 2 compounds. The NIH database lists 4: nitrous oxide, phosphorus oxychloride, phosphorous trichloride, and thionyl chloride (although it's important to note these values aren't always standardized; some authorities consider phosphorus oxychloride to be Health 3, for example). Based on the street value and the number of US agencies who would be concerned about it, my guess is thionyl chloride, a useful industrial chemical which is also used in at least one meth lab synthesis pathway... AND highly regulated as a chemical weapon precursor (to both sulfur mustard and G-series nerve agents). Oh, and it is absolutely a Disposal Pain 4 candidate, too. [[User:Qalyar|Qalyar]] ([[User talk:Qalyar|talk]]) 04:52, 28 June 2022 (UTC)<br /> :::Not sure what source you consulted for this? Nitrous oxide is 2/0/0/OX and phosphorus oxychloride is 3/0/2/W. The last two you mentioned are 4/0/2 but also carry the W (reacts with water) which is missing in Randall's sign. [[Special:Contributions/172.70.214.81|172.70.214.81]] 01:04, 29 June 2022 (UTC)<br /> ::::[https://webwiser.nlm.nih.gov/changeSearchNFPA This] search tool from the NIH. I'll blame them for any weirdness (and admittedly, I was a bit surprised to see nitrous oxide at 4/0/2). [[User:Qalyar|Qalyar]] ([[User talk:Qalyar|talk]]) 01:54, 29 June 2022 (UTC)<br /> : It could be the drop ceiling - if it's even moderately unstable that would certainly make it a hazard; it would be a pain in the arse to dispose of; there are probably a few agencies with an interest building regs, etc. that would want to know about it. I'm not sure what kind of street price it would command, though. [[Special:Contributions/172.70.85.211|172.70.85.211]] 16:20, 28 June 2022 (UTC)<br /> :It could be something that wouldn't normally be classified as a material, like a velociraptor. I'd think more government agencies would want to know about their existence in reality, but it's possible in this universe their existence is less atypical. [[User:Edda|Edda]] ([[User talk:Edda|talk]]) 00:03 29 June 2022 (UTC)<br /> ::Velociraptors would be quite lightweight and extremely valuable, though, so I suspect the street value would be higher. [[Special:Contributions/172.70.91.62|172.70.91.62]] 08:40, 29 June 2022 (UTC)<br /> <br /> The center square is a free space, but if you win without it you get a special bonus prize. [[Special:Contributions/172.70.42.129|172.70.42.129]] 04:18, 28 June 2022 (UTC)<br /> <br /> Given Randall's fixation with velociraptors, is anyone else thinking the &quot;dropped ceiling&quot; may be a reference to the labs in Jurassic Park?<br /> :Possible. The first thing I had to think of was HalfLife (ie Black Mesa). [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 07:34, 28 June 2022 (UTC)<br /> :Since as a German I never heard of a dropped ceiling before, I automatically assumed it's a ceiling that drops on you. Ouch. [[Special:Contributions/172.71.102.117|172.71.102.117]] 19:28, 28 June 2022 (UTC)<br /> :: We call them &quot;Zwischendecke&quot; ;) [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 08:42, 29 June 2022 (UTC)<br /> ::: As an English speaker myself (rightpondian), I had to say I never knew the term before this comic. To me, they always were &quot;suspended ceilings&quot; (as, apparently, pretty much all the patents for them are, when I checked). Or maybe &quot;false ceiling&quot; but that might include no-gap re-lining to make a plaster ceiling look like it's wood. But &quot;drop ceiling&quot; (reminiscent of the &quot;drop bear&quot;!) is yet another thing our leftpodian cousins surprise me with. ;)<br /> ::: (Sometimes the gap itself is known to me as &quot;crawlspace&quot;, though of course you rarely can physically crawl there, not being man-rated (nor ever having ventilation-ducts of convenient me-size, because we tend not to do that so much in the UK), and I've never felt I could escape (say) velociraptors by heading up there, but it's definitely where I &quot;crawl&quot; cables, every now and then, adding new network cables to any given office space, and I can tell you how dusty it gets up there. I've never thought it more than 'ambient' dust, as nice or nasty as that might be considered, but as I feed/thrown cables around from one edge of a room to another I find that it's best done at the end of a work day, and not just so I don't have to work around those who sit beneath...) [[Special:Contributions/172.70.90.173|172.70.90.173]] 11:37, 29 June 2022 (UTC)<br /> <br /> <br /> Does Randall watch Warsaw local news? Yesterday [https://tvn24.pl/tvnwarszawa/mokotow/warszawa-wilanow-ul-branickiego-straz-miejska-interweniowala-w-sprawie-walacego-sie-budynku-5766504 there was an article about an accident with dropped ceiling]. Accident with dropped ceiling next day on xkcd gave me uncanny feeling. [[User:Tkopec|Tkopec]] ([[User talk:Tkopec|talk]]) 09:31, 28 June 2022 (UTC)<br /> :I was wondering whether the whole thing was inspired by the {{w|2022 Aqaba toxic gas leak}}, that it was published well within a day of. Probably not (because 'too soon', especially with deciding what humour to add, assuming he started from scratch) but he might well have heard of it even as he was already mid-way through the drawing/publishing process and felt it ok to press ahead (perhaps modified to make it ''less'' likely to be directly associated in some way).<br /> :Not worth an in-explanation (or Trivia) mention, but saying it here as a dismissable aside. [[Special:Contributions/172.70.162.5|172.70.162.5]] 13:58, 28 June 2022 (UTC)<br /> <br /> The &quot;''Number of times it's caused one of those terrifying lab accidents that chemists tell scary stories about late at night -&gt; 2''&quot; reminds me of the [https://www.science.org/topic/blog-category/things-i-wont-work-with Things I Won't Work With] category on Derek's Lowe blog, including famous [https://www.science.org/content/blog-post/sand-won-t-save-you-time Sand Won't Save You This Time] article about dangers of chlorine trifluoride, with a few ''scary stories'' included. --[[User:JakubNarebski|JakubNarebski]] ([[User talk:JakubNarebski|talk]]) 11:04, 28 June 2022 (UTC)<br /> :The &quot;smelling weird&quot; one made me remember the one about [https://www.science.org/content/blog-post/things-i-won-t-work-thioacetone thioacetone]--[[Special:Contributions/172.71.114.63|172.71.114.63]] 12:53, 28 June 2022 (UTC)<br /> :How about the aliens going through the ceiling crawlspaces in &quot;Aliens&quot;? [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 17:46, 29 June 2022 (UTC)<br /> <br /> &quot;Weird lab where it's about the soda machine&quot; example, from the Bourne Physics/Chemistry Building at Royal Holloway, University of London (but I'm struggling to find a source I can cite) had a story that was always told on &quot;new student tours&quot; / open days etc. There's a corridor there where an odd pattern of the floor tiles don't match, approx down the middle of most of one corridor, to the vending machine at the end of the hall, which also has 2 mismatched buttons. It's not 100% clear what the unlucky individual did to become highly radioactive, but he then allegedly decided he needed a drink. Later, the clean-up crew, after decontaminating the room where the accident occurred, could tell using a Geiger Counter exactly what route the guy took to the soda machine, including where he staggered - particular floor tiles were radioactive enough to remove and dispose of as &quot;radioactive waste&quot;, replacing them with tiles that evidently didn't match the originals very well. Similarly, from the 2 mis-matched buttons on the machine, you can tell from what row/col the unfortunate victim ordered as his last drink. [[Special:Contributions/108.162.241.9|108.162.241.9]] 02:58, 29 June 2022 (UTC)<br /> <br /> I don't want to get involved in someone's edit-war, but I think the reasonings behind [https://www.explainxkcd.com/wiki/index.php?title=2638:_Extended_NFPA_Hazard_Diamond&amp;diff=prev&amp;oldid=288088 this edit] are easily refutable:<br /> * ''all other squares have descriptions'' - yes, but all other squares have arrows to indicate an externalised description, there's no reason to believe that this would not have an arrow pointed at it from outside ''or'' inside, at a push. It may even be self-descriptive, but there's no reason to believe it isn't fully diagetic<br /> * ''parenthesis wouldn't be used for a symbol'' - but a strikethrough would? Because it is...<br /> ** If anything, less ludicrous (potentially a strike against my final theory, mentioned below, which I will admit for completeness)<br /> ** You would have better mentioned that it's big and entire words, not a diagraph/monograph abbreviation, but you didn't (and I think it wouldn't work as &quot;SH&quot;/whatever anyway, at any level of joke).<br /> ** Parentheses aren't used for any other non-diagetic label, though we could argue the toss about whether they are the ''replacement'' for the arrow (which I think could have been drawn just as easily) and I think this aspect is a stalemate in this particular argument, but it's one I did consider when thinking about the merits of the various edits.<br /> * ''and &quot;Special Hazard&quot; is the square description synonym used in the non-Wikipedia reference link at the top of the table'' - not &quot;Special Notice&quot;? (The link may have changed since I first followed it, with interest, as we don't have these diamonds over here, we use {{w|Hazchem}} boards... nothing like seeing a bit of 3YE flammable liquid on the move! ...but whereve I first checked it certainly wasn't &quot;Special Hazard&quot;.)<br /> ...I think it is intended as a rather clever self-referential joke. Why leave the square empty, except for the rather boring 'real' description? At least the other three standard sub-diamonds have some food for thought in their indicated values. Very unlike Randall to do ''nothing'' in that space when all kinds of real fun could have been had. I think I also believe (along with at least one other editor out there) that this is the particular fun that he decided to have with it. Much more believable than the alternative, IMO. (YMMV, HTH, HAND, ETLA...) [[Special:Contributions/162.158.34.61|162.158.34.61]] 23:25, 2 July 2022 (UTC)<br /> <br /> : Absolutely not. None of the even non-standard symbols are more than four capital letters long. If Randall had meant the text to be anything other than a description, he would have used '''SH'''. The link that calls the white square &quot;Special Hazard&quot; is http://www.ilpi.com/msds/ref/nfpa.html Furthermore, what exactly is the joke supposed to be, again? [[Special:Contributions/172.70.211.52|172.70.211.52]] 00:33, 3 July 2022 (UTC)<br /> ::(Isn't most of that already fully covered by 162.etc... New arguments are needed, or write it as maybe/maybe not. I think absolutes are unlikely to prove, either way.)<br /> ::Some other editor said they changed the description of Special Hazard (not the transcripted contents, but the reality of the actual square) to &quot;Special Notice&quot;, for apparently good reasons related to some link, IIRC, but maybe that's inconsistencies in how the standards-body documents it or something.<br /> ::But whatever.... not my argument.[[Special:Contributions/172.70.162.77|172.70.162.77]] 01:28, 3 July 2022 (UTC)<br /> <br /> :I agree with 172.70.211.52 that this is a mistaken idea and should be removed from the explanation. [[Special:Contributions/172.68.132.96|172.68.132.96]] 22:35, 3 July 2022 (UTC)<br /> <br /> ::As it's being argued over again, with an absolutist (or maybe &quot;absolutely not!&quot;-ist) unilateral wish to remove all such speculation, I'm just gonna mention that [[1815|'unintentional']] and [[2528|intentional]] literalism is a recurring xkcd theme for depictions of symbolic pennants, whatever the actual degree of intention this time round. From &quot;Ha ha... No, never actually thought to do that&quot; through to &quot;*sigh* - I shouldn't need to explain the whole joke, folks! You take this far too seriously''[1]'', just enjoy the bits you understand...&quot;. If you go and pester Randall on Twitter/whatever and get his word that it's the former, then perhaps you can consign it to &quot;confirmed not to be this&quot;, but then you'd be obliged to report the possibility in order to show the refutation itself, so probably counter-productive even if proven correct... ;) Leaving it as &quot;it possibly might be...&quot;/whatever the best wording, however, does not make any insistance that it ''is'', but certainly adds something to the kind of person like me who likes to see what others have gotten from the comic (however wrong). [[Special:Contributions/172.70.86.64|172.70.86.64]] 16:06, 14 July 2022 (UTC)<br /> :::[1] Incidentally, I think I'd be right to say that sometimes we do! Often even! ^_^<br /> ::::I have proposed a [https://www.explainxkcd.com/wiki/index.php?title=2638:_Extended_NFPA_Hazard_Diamond&amp;diff=288836&amp;oldid=288828 compromise using small text.] [[Special:Contributions/172.70.211.36|172.70.211.36]] 16:23, 14 July 2022 (UTC)</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2638:_Extended_NFPA_Hazard_Diamond&diff=288836 2022-07-14T16:21:25Z

<p>172.70.211.36: Compromise proposal: small text</p> <hr /> <div>{{comic<br /> | number = 2638<br /> | date = June 27, 2022<br /> | title = Extended NFPA Hazard Diamond<br /> | image = extended_nfpa_hazard_diamond.png<br /> | titletext = With most labs, the hushed horror stories are about something like dimethylmercury or prions, but occasionally you'll get a weird lab where it's about the soda machine or the drop ceiling.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a SUBSTANCE WORTH $500 IN STREET VALUE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> This comic depicts an extension of the National Fire Protection Association's {{w|NFPA 704|NFPA 704 Standard System for the Identification of the Hazards of Materials for Emergency Response}} &quot;fire diamond&quot; emblematic insignia used to warn about the properties of hazardous substances inside a building, vehicle, room, cabinet, or container that are important during an emergency or accident, such as a fire, earthquake, spill or leak, bringing the diamond from 2x2 squares to 3x3 by adding five variously useful and humorous squares along the bottom edges.<br /> <br /> The numbers in a normal NFPA 704 diamond do not specify values of substances' properties, but rather broad categories designating characteristics of the substances of greatest interest to {{w|first responders}} and hazardous materials cleanup crews. Randall's expanded diamond breaks with this convention, with several squares (Lilac, Orange, and Black) denoting absolute values, and one square (Green) denoting an economic value. This could very easily lead to documentation update headaches, especially since the Green square is mostly determined by supply and demand, and the Lilac square is linked to political outcomes.<br /> <br /> {| class=&quot;wikitable&quot;<br /> |+ Squares and explanations<br /> |-<br /> ! Square !! Color !! Comic text !! Explanation<br /> |-<br /> !colspan=5| Real NFPA 704 diamond [http://www.ilpi.com/msds/ref/nfpa.html square and number meanings]<br /> |-<br /> | Top || Red || Flammability (0) || Denotes flammability. 0 indicates &quot;materials that will not burn.&quot;<br /> |-<br /> | Top Left || Blue || Health Hazard (4) || Denotes the danger that the substance(s) pose to living beings in ways other than flammability and reactivity. 4 indicates that &quot;Very short exposure could cause death or serious residual injury even though prompt medical attention was given.&quot;<br /> |-<br /> | Top Right || Yellow || Instability (2) || Denotes how stable the substance(s) are when exposed to water, heat, shock, air, or other substances. 2 indicates that &quot;Normally unstable and will readily undergo violent decomposition but does not detonate. Also: may react violently with water or may form potentially explosive mixtures with water.&quot;<br /> |-<br /> | Center || White || (Special Hazard) || The standard's &quot;Special Notice&quot; field may contain a symbol denoting additional information about the substance(s), e.g., '''OX''' for {{w|oxidizer}}s, '''SA''' for simple {{w|asphyxiant}} gases such as nitrogen and helium, and &lt;s&gt;'''W'''&lt;/s&gt; for substances which react dangerously with water. &lt;small&gt;Since the other squares in Randall's diamond contain values instead of descriptions, &quot;'''(Special Hazard)'''&quot; could conceivably be the special notice symbol for the substance depicted, instead of a description of the square's purpose.&lt;/small&gt;<br /> |-<br /> !colspan=5| After this point, all squares are made up by Randall.<br /> |-<br /> | Center Left || Green || Number of digits in the street value ($/gram) (2) || Describes the order of magnitude of the price (in USD) of one gram of the substance when sold illegally and informally. This is done on a logarithmic scale, with a '1' selling for $9/gram or less, a '2' selling for $10-$99/gram, and so on. As such this is the first of several squares where the number may presumably go to 5 or above (which is not allowed on the original Blue/Red/Yellow squares, as they do not denote strict numerical values). That said it's not immediately clear how substances which command &lt;$1/gram would be handled.<br /> <br /> Randall's example substance apparently sells for tens of dollars per gram (which would be similar to most common illicit drugs).<br /> |-<br /> | Center Right || Dark Purple || How much of a hassle it is to dispose of (4) || While many things can be thrown in the trash with no additional procedures, substances that merit an NFPA 704 square often require additional procedures to avoid significant danger, damage to the environment, or hefty dumping fines. Biohazards that may carry diseases are often disposed of in special containers, and nuclear materials are notoriously difficult to safely dispose of. This square would be at least theoretically useful, though not as much as the actual disposal guidelines.<br /> <br /> If the numbering here follows the scheme of the real categories, Randall's example substance is about as hard to dispose of as it gets. This matches the substance's rating of 4 for Blue and 2 for Yellow. Presumably it requires highly specialized handling or processing, and may also very bulky or awkward to store.<br /> |-<br /> | Bottom Left || Lilac || Number of federal agencies who want to know if you have any (3) || In many countries, including Randall's home country, the USA, the government has agencies dedicated to controlling or limiting the use of regulated substances, due to their use as drugs, weapons, harm to the environment, etc. While any given substance might be of interest to one agency, something that is both an environmental hazard and a chemical weapon component could interest, for example, the {{w|EPA}}, {{w|Chemical Safety Board}} and the FBI Counter-terrorism Division.<br /> |-<br /> | Bottom Right || Orange || How many times you have to scrub your hands after touching it before they stop smelling weird (1) || While the real NFPA 704 chart describes properties ranging from unsafe to potentially deadly, this square describes a minor but very real inconvenience. Some things are harder to wash off your hands than others, and, given that most people don't often work with dangerous substances {{Citation Needed}}, this would be a more common, but less relevant, concern for many people.<br /> <br /> In this case, the substance, or its residue, seems to be fairly easy to wash off. This is seemingly incongruous with its ratings in the Blue and Black squares (see below), though it's possible that this substance simply doesn't have a strong odor.<br /> |-<br /> | Bottom || Black || Number of times it's caused one of those terrifying lab accidents that chemists tell scary stories about late at night (2) || This square might show how concerned and careful someone should be in handling the substance in question, especially if the number is more than one. However, it would be dependent not just on how inherently dangerous the substance is, but also on how commonly it occurs in labs. It's also vague as to what kind of accidents it has been involved in and what precautions therefore need to be taken. It could, for example, have caused some terrifying reaction, destroying things around it, or it could be very large and unwieldy and liable to crush people if handled improperly.<br /> <br /> In this case, it seems the substance has caused two such accidents, presumably on account of its high health risk of 4 in the Blue square, and may also be linked to its hazardous disposal score of 4 in the Purple square.<br /> |}<br /> <br /> The title text (which references &quot;scary stories&quot; of the Black square) refers to {{w|dimethylmercury}} and {{w|prions}}. Dimethylmercury, C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;Hg, is an organic form of mercury with an NFPA score of 4-4-3 (contact can be fatal, will burn below 73° F (22 °C), will combust if put under pressure). In 1997, an American chemist, {{w|Karen Wetterhahn}}, died 298 days after a few drops of C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;Hg on her latex gloves were absorbed into her hand through the gloves, causing fatal mercury poisoning. Despite her having followed all safety protocols of the time, it was not then understood that the chemical was so toxic, nor that latex was so permeable to it. Prions are misfolded proteins that are responsible for a number of neurodegenerative diseases, including {{w|mad cow disease}} and {{w|chronic wasting disease}} in non-human animals and {{w|Creutzfeldt-Jakob disease}} in humans. These would indeed be the kind of substances that would scare those working with them in their labs; if an accident occurred, the results could be calamitous. See for example the case of [https://arstechnica.com/science/2021/07/second-lab-worker-with-deadly-prion-disease-prompts-research-pause-in-france/ Émilie Jaumain], a lab technician who died after accidentally coming into contact with prions in mouse tissue.<br /> <br /> But a few labs have apparently had accidents involving a soda machine or {{w|dropped ceiling}}. The latter may be a reference to {{w|1978 smallpox outbreak in the United Kingdom|the death of Janet Parker}}: One inquiry found that she was infected with {{w|smallpox}} when a sample traveled upward from a lab on the floor below hers; however, other investigations have challenged that finding. There are occasional instances of vending machines causing injury or death, usually caused by people trying to shake or tilt the machines to get product out and having the machine tip and fall on them. On average, [https://www.cpsc.gov/Newsroom/News-Releases/1996/CPSC-Soda-Vending-Machine-Industry-Labeling-Campaign-Warns-Of-Deaths-And-Injuries a couple of Americans per year] are killed in this way. Reagents obtained in this way tend to have more impurities than those usually used in labs, but are relatively safe to shake.<br /> <br /> The only easily identifiable substance which could likely meet the specific insignia numbers shown in the comic is {{w|thionyl chloride}} (SOCl&lt;sub&gt;2&lt;/sub&gt;), a chlorinating reagent and solvent regulated as a chemical weapons precursor and sometimes used in the production of methamphetamine, which would also be represented with the '''&lt;s&gt;W&lt;/s&gt;''' symbol inside the white square, indicating reactivity with water. &lt;small&gt;But if '''(Special Hazard)''' is the literal &quot;Special Notice&quot; classification in use then something far more exotic may be involved.&lt;/small&gt;<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> :Know your extended NFPA hazard diamond:<br /> <br /> :[The diamond is divided into 3x3 squares.]<br /> :Flammability: 0 (top, red)<br /> :Health hazard: 4 (top-left, blue)<br /> :Instability/reactivity: 2 (top-right, yellow)<br /> :Number of digits in the street value ($/gram): 2 (left, green)<br /> :(Special hazard) (center, white)<br /> :How much of a hassle it is to dispose of: 4 (right, purple)<br /> :Number of federal agencies who want to know if you have any: 3 (bottom-left, pink)<br /> :How many times you have to scrub your hands after touching it before they stop smelling weird: 1 (bottom-right, orange)<br /> :Number of times it's caused one of those terrifying lab accidents that chemists tell scary stories about late at night: 2 (bottom, black)<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Science]]<br /> [[Category:Chemistry]]<br /> [[Category:Comics with color]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2645:_The_Best_Camera&diff=288835 2022-07-14T16:06:39Z

<p>172.70.211.36: /* Explanation */ explain further</p> <hr /> <div>{{comic<br /> | number = 2645<br /> | date = July 13, 2022<br /> | title = The Best Camera<br /> | image = the_best_camera.png<br /> | titletext = The best camera is the one at L2.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a SET OF OPTICAL FILTERS - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> [https://www.goodreads.com/book/show/6921300-the-best-camera-is-the-one-that-s-with-you ''The Best Camera Is The One That's With You''] is a book by photographer {{w|Chase Jarvis}}, celebrating mobile phone cameras, not for their technical quality, but rather for the fact that people usually have them when interesting subjects appear. This advice is often given to novice photographers; sometimes phrased as, &quot;The best camera is the one you use most.&quot; A cheap camera is better than an expensive professional camera if it is more often with the photographer, for example if it is light-weight enough to be carried on hiking trips. A fancy expensive camera that isn't available to use is of no value for taking pictures.<br /> <br /> In this case, however, &quot;the best camera&quot; refers to the {{w|James Webb Space Telescope}} (JWST), the spacecraft depicted in the third panel, which cost $10 billion—[https://screenrant.com/james-webb-space-telescope-cost-how-much/ $9.5 billion over budget]—and was [[2014: JWST Delays|fifteen years late]]. It can be considered a camera because it takes pictures, and it's the best {{w|space telescope}} to date in terms of {{w|aperture}} size and thus {{w|angular resolution}}.[https://astronomy.stackexchange.com/questions/26373/relation-between-angular-resolution-and-aperture] The first pictures taken by the telescope were released on 11-12 July 2022, a few days before this comic was published.[https://www.nasa.gov/webbfirstimages] The pictures from JWST show objects as they were [https://webbtelescope.org/contents/media/images/2022/035/01G7HRYVGM1TKW556NVJ1BHPDZ as much as 13.1 billion years ago,] which is unprecedented. The telescope has [https://www.stsci.edu/jwst/instrumentation three instruments that can act as &quot;cameras&quot; for imaging,] a fourth {{w|optical spectrometer|spectrometer}} instrument, and many dozens of {{w|optical filter}}s. Because the telescope can only take infrared photographs invisible to the human eye, [https://jwst-docs.stsci.edu/files/97978094/97978104/1/1596073152120/NIRCam_filters_modules.png each of the filters has been assigned a standardized visible color] to convert images for viewing. However, astronomers are encouraged to use [https://www.youtube.com/watch?v=-dmiS_6YrGU&amp;t=449s other color schemes] when observing a limited portion of the filters' range or rendering {{w|interferometry}},[https://jwst-docs.stsci.edu/jwst-near-infrared-imager-and-slitless-spectrograph/niriss-observing-modes/niriss-aperture-masking-interferometry][https://jwst-docs.stsci.edu/jwst-near-infrared-camera/nircam-observing-modes/nircam-coronagraphic-imaging][https://jwst-docs.stsci.edu/jwst-mid-infrared-instrument/miri-observing-modes/miri-coronagraphic-imaging] and to [https://www.youtube.com/watch?v=sNJR3lenz1I&amp;t=293s convert very distant objects to their original color] from {{w|redshift}}ed infrared when possible. The capabilities of the JWST are likely to soon answer many difficult astronomical, astrophysical, and [[2643: Cosmologist Gift|cosmological]] questions that had been previously undecidable, along with important questions about the {{w|biosignature}}s of {{w|exoplanet}}s.<br /> <br /> The title text references {{w|Lagrange Point|Lagrange Point 2}} (L&lt;sub&gt;2&lt;/sub&gt;). The Lagrange Points are five locations corresponding to stationary regions of the {{w|restricted three-body problem}}, in which one of the bodies is much less massive than the other two. A low-mass body in one of those locations is able to be roughly stationary relative to the other two bodies with very little fuel needed for trajectory corrections. In this case, the JWST orbits around the L&lt;sub&gt;2&lt;/sub&gt; point of the Earth-Sun system [https://space.stackexchange.com/a/57378 rather than being stationed exactly at it] to avoid shadows from the Earth and Moon that would cause harmful temperature and power variations.[https://ntrs.nasa.gov/citations/20190028885] Thus it avoids the problem the {{w|Hubble Space Telescope}} had orbiting the Earth, allowing only a short observation window per orbit—the HST could be used for only about 55 minutes of each of its 95 minute orbits for observations not sufficiently above or below its orbital plane.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Each panel features an image of space, with text printed in white at the top of each panel. The first panel says:]<br /> :They say the best camera is the one you have with you.<br /> <br /> :[A panel showing more stars and galaxies visible.]<br /> :It turns out <br /> <br /> :[A panel showing even more stars and galaxies visible. At the center of the panel is an outline drawing in white of the James Webb Space Telescope.]<br /> :they're wrong.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Astronomy]]<br /> [[Category:Telescopes]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=Talk:2645:_The_Best_Camera&diff=288833 2022-07-14T16:02:22Z

<p>172.70.211.36: Typo</p> <hr /> <div>&lt;!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--&gt;<br /> Removed the part about L2 being in Earth's umbra. Although this is true, the JWST is not actually ''at'' L2; it revolves around L2, specifically to avoid being in the Earth's umbra (and the moon's) and therefore avoid changes in temperature. [[User:DKMell|DKMell]] ([[User talk:DKMell|talk]]) 17:52, 13 July 2022 (UTC)<br /> <br /> Does anyone know whether they use [https://ds9.si.edu/doc/user/rgb/index.html SAOImageDS9] or [https://docs.astropy.org/en/stable/visualization/rgb.html Astropy] to make full color images? Both are listed under [https://www.stsci.edu/jwst/science-execution/data-analysis-toolbox post-pipeline tools.] General instructions are in [https://arxiv.org/pdf/2001.02618.pdf this paper] but it's not a software tutorial, and it doesn't mention un-redshifting very distant objects like in [https://www.youtube.com/watch?v=sNJR3lenz1I&amp;t=293s Dr. Becky's video] (and which they didn't do completely for the deep field because the lensed galaxies were actually red.) [[Special:Contributions/172.70.206.213|172.70.206.213]] 05:35, 14 July 2022 (UTC)<br /> :Can we use the published image data files to produce a SMAC 0723 image with only the far-redshifted, lensed objects? [[Special:Contributions/172.70.211.36|172.70.211.36]] 16:01, 14 July 2022 (UTC)<br /> <br /> When discussing biosignatures of exoplanets, should we draw the distinction between ozone and water? [[Special:Contributions/162.158.106.113|162.158.106.113]] 11:58, 14 July 2022 (UTC)</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=Talk:2645:_The_Best_Camera&diff=288832 2022-07-14T16:01:31Z

<p>172.70.211.36: Question</p> <hr /> <div>&lt;!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--&gt;<br /> Removed the part about L2 being in Earth's umbra. Although this is true, the JWST is not actually ''at'' L2; it revolves around L2, specifically to avoid being in the Earth's umbra (and the moon's) and therefore avoid changes in temperature. [[User:DKMell|DKMell]] ([[User talk:DKMell|talk]]) 17:52, 13 July 2022 (UTC)<br /> <br /> Does anyone know whether they use [https://ds9.si.edu/doc/user/rgb/index.html SAOImageDS9] or [https://docs.astropy.org/en/stable/visualization/rgb.html Astropy] to make full color images? Both are listed under [https://www.stsci.edu/jwst/science-execution/data-analysis-toolbox post-pipeline tools.] General instructions are in [https://arxiv.org/pdf/2001.02618.pdf this paper] but it's not a software tutorial, and it doesn't mention un-redshifting very distant objects like in [https://www.youtube.com/watch?v=sNJR3lenz1I&amp;t=293s Dr. Becky's video] (and which they didn't do completely for the deep field because the lensed galaxies were actually red.) [[Special:Contributions/172.70.206.213|172.70.206.213]] 05:35, 14 July 2022 (UTC)<br /> :Can we use the published image data files to produce a SMAC 0732 image with only the far-redshifted, lensed objects? [[Special:Contributions/172.70.211.36|172.70.211.36]] 16:01, 14 July 2022 (UTC)<br /> <br /> When discussing biosignatures of exoplanets, should we draw the distinction between ozone and water? [[Special:Contributions/162.158.106.113|162.158.106.113]] 11:58, 14 July 2022 (UTC)</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2644:_fMRI_Billboard&diff=288823 2022-07-14T13:19:56Z

<p>172.70.211.36: Update per instructions</p> <hr /> <div>{{comic<br /> | number = 2644<br /> | date = July 11, 2022<br /> | title = fMRI Billboard<br /> | image = fmri_billboard.png<br /> | titletext = [other side] If the first word of an instruction you're given starts with the same letter as your crush's name, for that step imagine the experimenter is your crush.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by A STATISTICAL ANOMALY THAT CHANGES EVERYONE'S MEDICAL RECORDS - Do NOT delete this tag too soon.}}<br /> <br /> {{w|Functional magnetic resonance imaging}}, or fMRI, is a method of {{w|4DCT|four-dimensional computed tomography}} able to record animated multi-layered images of brain activity by detecting blood flow changes apparent from magnetic differences between oxygenated and deoxygenated {{w|hemoglobin}}. Scientists use fMRI to try to detect deception and false memories,[https://www.sciencedirect.com/science/article/pii/S0149763419301873] plan brain surgery,[https://www.sciencedirect.com/science/article/pii/S2213158217303133] and understand the relationship between brain structures and cognition,[https://www.sciencedirect.com/science/article/pii/S0149763419300879] among many other investigations. Volunteer research subjects [https://www.clinicaltrials.gov/ participate in such studies] by lying inside large toroidal scanners while conducting tasks with projected images, sounds, etc.<br /> <br /> This comic shows a billboard erected by a neuroscience department in an attempt at sabotaging a rival department's volunteer subject compliance with their fMRI study instructions, by suggesting behaviors which would likely produce unexpected results, such as recalling a frightening memory after seeing similar stimulus slides, or imagining the lab technician is a romantic interest when reading words that begin with the same letter as their name. This is funny because academic department rivalries do not usually lead to sabotage,{{citation needed}} and in the rare cases when they do, it's usually clandestine instead of so absurdly blatant. The comic also shows neuroscience in terms of the technologies used to study it, and how experiment instructions can influence its development.<br /> <br /> Following such suggestions or even inadvertently remembering them during an fMRI could very well interfere with its results. fMRI experiments are often criticized because they have low {{w|statistical power}} and can easily be confounded by experiment subject error in following instructions, among many other variables. In a famous 2009 study, a dead fish was shown to have apparent evidence of brain activity when scanned with ordinary fMRI techniques.[http://prefrontal.org/files/posters/Bennett-Salmon-2009.pdf] In 2015, discovery of a statistical error invalidated at least 40,000 fMRI studies.[https://www.sciencealert.com/a-bug-in-fmri-software-could-invalidate-decades-of-brain-research-scientists-discover] Subsequently in 2017, many more fMRI results were further discredited due to poor software parameter selection.[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5487467]<br /> <br /> The title text indicates that the sabotaging instructions are printed on both sides of the billboard, suggesting that it might have been erected on the grounds of the targeted rival department. Alternately, the instructions on the other side may be intended to disrupt research at the other institution.<br /> <br /> ==Transcript==<br /> :[A large, building-sized billboard rises over what appears to be a college campus. The sign is supported by two sturdy planks disappearing behind one of two long one story buildings lying next to each other. The board is higher than the buildings and almost as long as the one it stands behind. That building seems to have a flat roof where the other has a peaked roof. It could, though, be a matter of perspective, and that both buildings have the same kind of peaked roof. There are several windows visible in both buildings and a door in the middle of the one with the billboard. There is a forest behind the buildings. In front of the main building there is a path with a round area just outside the door. The path goes past the next building, with yet another round area between the buildings. These round areas are where two paths crosses. Megan is standing outside the door, Cueball walks towards the round area between the buildings, Ponytail sits on the grass between the two paths going away from the buildings, she sits near a tree. Closer to the tree and also closer to the buildings another Ponytail like girl is standing together with Hairbun. The sign reads:]<br /> : ⚠ Student fMRI study volunteers ⚠<br /> : Remember, when you're in the scanner, if you see a slide that's similar to one they already showed you, think as hard as you can about your scariest memory.<br /> <br /> :[Caption below panel:] <br /> :A rival neuroscience department keeps trying to sabotage our experiments.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Comics featuring Megan]]<br /> [[Category:Comics featuring Cueball]]<br /> [[Category:Comics featuring Ponytail]]<br /> [[Category:Comics featuring Hairbun]]<br /> [[Category:Science]]<br /> [[Category:Psychology]]<br /> [[Category:Biology]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2645:_The_Best_Camera&diff=288750 2022-07-14T04:16:05Z

<p>172.70.211.36: /* Explanation */ word choice</p> <hr /> <div>{{comic<br /> | number = 2645<br /> | date = July 13, 2022<br /> | title = The Best Camera<br /> | image = the_best_camera.png<br /> | titletext = The best camera is the one at L2.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by an AMATEUR PHOTOGRAPHER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> ''The Best Camera Is The One That's With You'' [https://www.goodreads.com/book/show/6921300-the-best-camera-is-the-one-that-s-with-you] is a book by photographer Chase Jarvis, celebrating mobile phone cameras, not for their photographic or technical quality but rather for the fact that you always have it when an interesting subject appears. This is advice often given to novice photographers, sometimes with the slight change &quot;The best camera is the one you use most.&quot; A cheap {{w|Nikon Coolpix}} camera can be better than a professional {{w|Canon EOS}}, simply for the fact it is lightweight enough to be taken on ''every'' voyage you'll make. A fancy expensive camera that isn't at hand for you to use is of no value for taking pictures.<br /> <br /> However, in this case &quot;the best camera&quot; refers to the {{w|James Webb Space Telescope}} (JWST), the spacecraft depicted in the third frame. It can be considered a camera because it takes pictures. The first pictures taken by the telescope were released on 11-12 July 2022, days before this comic was published.[https://www.nasa.gov/webbfirstimages] The pictures from JWST show objects as they were [https://webbtelescope.org/contents/media/images/2022/035/01G7HRYVGM1TKW556NVJ1BHPDZ as much as 13.1 billion years ago,] which is unprecedented. The telescope has [https://www.stsci.edu/jwst/instrumentation three instruments that can act as &quot;cameras&quot; for imaging,] a fourth {{w|optical spectrometer|spectrometer}}-only instrument, and twelve {{w|optical filter}}s. Because the telescope can only take infrared photographs invisible to the human eye, [https://jwst-docs.stsci.edu/files/97978948/131367586/1/1633276536459/NIRISS_effective_throughputs_etcv1.6.1.png each of the filters has been assigned a standardized visible color] to convert images for viewing. (However, astronomers are encouraged to use other color schemes when using a subset of the filters' range or are rendering {{w|interferometry}} from the [https://jwst-docs.stsci.edu/jwst-near-infrared-imager-and-slitless-spectrograph/niriss-observing-modes/niriss-aperture-masking-interferometry NIRISS Aperture Masking Interferometer] or the [https://jwst-docs.stsci.edu/jwst-mid-infrared-instrument/miri-observing-modes/miri-coronagraphic-imaging MIRI Coronagraph.])<br /> <br /> The title text references {{w|Lagrange Point|Lagrange Point 2}} (L&lt;sub&gt;2&lt;/sub&gt;). The Lagrange Points are a set of five locations which are solutions to the restricted three-body problem, in which one of the three bodies is much less massive than the other two. A low-mass body in one of these locations is able to be stationary relative to the other two bodies with very little fuel needed for trajectory corrections. In this case, the JWST orbits around the L&lt;sub&gt;2&lt;/sub&gt; point of the Earth-Sun system [https://space.stackexchange.com/a/57378 rather than being stationed exactly at it] to avoid shadows from the Earth and Moon that would cause temperature variations in the instrument.[https://www.jwst.nasa.gov/content/observatory/sunshield.html] It avoids the problem the {{w|Hubble Space Telescope}} had orbiting around the Earth, allowing only a short observation window per revolution. The HST could be used for about 55 minutes of every 95-minute orbit for targets not sufficiently above or below the orbital plane.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Each panel features an image of space, with text printed in white at the top of each panel. The first panel says:]<br /> :They say the best camera is the one you have with you.<br /> <br /> :[A panel showing more stars and galaxies visible.]<br /> :It turns out <br /> <br /> :[A panel showing even more stars and galaxies visible. At the center of the panel is an outline drawing in white of the James Webb Space Telescope.]<br /> :they're wrong.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Astronomy]]<br /> [[Category:Telescopes]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2645:_The_Best_Camera&diff=288749 2022-07-14T04:15:10Z

<p>172.70.211.36: /* Explanation */ copyedit</p> <hr /> <div>{{comic<br /> | number = 2645<br /> | date = July 13, 2022<br /> | title = The Best Camera<br /> | image = the_best_camera.png<br /> | titletext = The best camera is the one at L2.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by an AMATEUR PHOTOGRAPHER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> ''The Best Camera Is The One That's With You'' [https://www.goodreads.com/book/show/6921300-the-best-camera-is-the-one-that-s-with-you] is a book by photographer Chase Jarvis, celebrating mobile phone cameras, not for their photographic or technical quality but rather for the fact that you always have it when an interesting subject appears. This is advice often given to novice photographers, sometimes with the slight change &quot;The best camera is the one you use most.&quot; A cheap {{w|Nikon Coolpix}} camera can be better than a professional {{w|Canon EOS}}, simply for the fact it is lightweight enough to be taken on ''every'' voyage you'll make. A fancy expensive camera that isn't at hand for you to use is of no value for taking pictures.<br /> <br /> However, in this case &quot;the best camera&quot; refers to the {{w|James Webb Space Telescope}} (JWST), the spacecraft depicted in the third frame. It can be considered a camera because it takes pictures. The first pictures taken by the telescope were released on 11-12 July 2022, days before this comic was published.[https://www.nasa.gov/webbfirstimages] The pictures from JWST show objects as they were [https://webbtelescope.org/contents/media/images/2022/035/01G7HRYVGM1TKW556NVJ1BHPDZ as much as 13.1 billion years ago,] which is unprecedented. The telescope has [https://www.stsci.edu/jwst/instrumentation three instruments which can act as &quot;cameras&quot; for imaging,] a fourth {{w|optical spectrometer|spectrometer}}-only instrument, and twelve {{w|optical filter}}s. Because the telescope can only take infrared photographs invisible to the human eye, [https://jwst-docs.stsci.edu/files/97978948/131367586/1/1633276536459/NIRISS_effective_throughputs_etcv1.6.1.png each of the filters has been assigned a standardized visible color] to convert images for viewing. (However, astronomers are encouraged to use other color schemes when using a subset of the filters' range or are rendering {{w|interferometry}} from the [https://jwst-docs.stsci.edu/jwst-near-infrared-imager-and-slitless-spectrograph/niriss-observing-modes/niriss-aperture-masking-interferometry NIRISS Aperture Masking Interferometer] or the [https://jwst-docs.stsci.edu/jwst-mid-infrared-instrument/miri-observing-modes/miri-coronagraphic-imaging MIRI Coronagraph.])<br /> <br /> The title text references {{w|Lagrange Point|Lagrange Point 2}} (L&lt;sub&gt;2&lt;/sub&gt;). The Lagrange Points are a set of five locations which are solutions to the restricted three-body problem, in which one of the three bodies is much less massive than the other two. A low-mass body in one of these locations is able to be stationary relative to the other two bodies with very little fuel needed for trajectory corrections. In this case, the JWST orbits around the L&lt;sub&gt;2&lt;/sub&gt; point of the Earth-Sun system [https://space.stackexchange.com/a/57378 rather than being stationed exactly at it] to avoid shadows from the Earth and Moon that would cause temperature variations in the instrument.[https://www.jwst.nasa.gov/content/observatory/sunshield.html] It avoids the problem the {{w|Hubble Space Telescope}} had orbiting around the Earth, allowing only a short observation window per revolution. The HST could be used for about 55 minutes of every 95-minute orbit for targets not sufficiently above or below the orbital plane.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Each panel features an image of space, with text printed in white at the top of each panel. The first panel says:]<br /> :They say the best camera is the one you have with you.<br /> <br /> :[A panel showing more stars and galaxies visible.]<br /> :It turns out <br /> <br /> :[A panel showing even more stars and galaxies visible. At the center of the panel is an outline drawing in white of the James Webb Space Telescope.]<br /> :they're wrong.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Astronomy]]<br /> [[Category:Telescopes]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2645:_The_Best_Camera&diff=288748 2022-07-14T04:12:52Z

<p>172.70.211.36: /* Explanation */ other nonstandard coloring modes</p> <hr /> <div>{{comic<br /> | number = 2645<br /> | date = July 13, 2022<br /> | title = The Best Camera<br /> | image = the_best_camera.png<br /> | titletext = The best camera is the one at L2.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by an AMATEUR PHOTOGRAPHER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> ''The Best Camera Is The One That's With You'' [https://www.goodreads.com/book/show/6921300-the-best-camera-is-the-one-that-s-with-you] is a book by photographer Chase Jarvis, celebrating mobile phone cameras, not for their photographic or technical quality but rather for the fact that you always have it when an interesting subject appears. This is advice often given to novice photographers, sometimes with the slight change &quot;The best camera is the one you use most.&quot; A cheap {{w|Nikon Coolpix}} camera can be better than a professional {{w|Canon EOS}}, simply for the fact it is lightweight enough to be taken on ''every'' voyage you'll make. A fancy expensive camera that isn't at hand for you to use is of no value for taking pictures.<br /> <br /> However, in this case &quot;the best camera&quot; refers to the {{w|James Webb Space Telescope}} (JWST), the spacecraft depicted in the third frame. It can be considered a camera because it takes pictures. The first pictures taken by the telescope were released on 11-12 July 2022, days before this comic was published.[https://www.nasa.gov/webbfirstimages] The pictures from JWST show objects as they were [https://webbtelescope.org/contents/media/images/2022/035/01G7HRYVGM1TKW556NVJ1BHPDZ as much as 13.1 billion years ago,] which is unprecedented. The telescope has [https://www.stsci.edu/jwst/instrumentation three instruments which can act as &quot;cameras&quot; for imaging,] a fourth {{w|optical spectrometer|spectrometer}}-only instrument, and twelve {{w|optical filter}}s. Because the telescope can only take infrared photographs invisible to the human eye, [https://jwst-docs.stsci.edu/files/97978948/131367586/1/1633276536459/NIRISS_effective_throughputs_etcv1.6.1.png each of the filters has been assigned a standardized visible color] to convert images for viewing. (However, astronomers are free to use other color schemes when they are only using a subset of the filters' range or are rendering {{w|interferometry}} from the [https://jwst-docs.stsci.edu/jwst-near-infrared-imager-and-slitless-spectrograph/niriss-observing-modes/niriss-aperture-masking-interferometry NIRISS Aperture Masking Interferometer] or the [https://jwst-docs.stsci.edu/jwst-mid-infrared-instrument/miri-observing-modes/miri-coronagraphic-imaging MIRI Coronagraph.])<br /> <br /> The title text references {{w|Lagrange Point|Lagrange Point 2}} (L&lt;sub&gt;2&lt;/sub&gt;). The Lagrange Points are a set of five locations which are solutions to the restricted three-body problem, in which one of the three bodies is much less massive than the other two. A low-mass body in one of these locations is able to be stationary relative to the other two bodies with very little fuel needed for trajectory corrections. In this case, the JWST orbits around the L&lt;sub&gt;2&lt;/sub&gt; point of the Earth-Sun system [https://space.stackexchange.com/a/57378 rather than being stationed exactly at it] to avoid shadows from the Earth and Moon that would cause temperature variations in the instrument.[https://www.jwst.nasa.gov/content/observatory/sunshield.html] It avoids the problem the {{w|Hubble Space Telescope}} had orbiting around the Earth, allowing only a short observation window per revolution. The HST could be used for about 55 minutes of every 95-minute orbit for targets not sufficiently above or below the orbital plane.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Each panel features an image of space, with text printed in white at the top of each panel. The first panel says:]<br /> :They say the best camera is the one you have with you.<br /> <br /> :[A panel showing more stars and galaxies visible.]<br /> :It turns out <br /> <br /> :[A panel showing even more stars and galaxies visible. At the center of the panel is an outline drawing in white of the James Webb Space Telescope.]<br /> :they're wrong.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Astronomy]]<br /> [[Category:Telescopes]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2645:_The_Best_Camera&diff=288740 2022-07-14T03:45:42Z

<p>172.70.211.36: /* Explanation */ -only because two of the cameras are also spectrometers</p> <hr /> <div>{{comic<br /> | number = 2645<br /> | date = July 13, 2022<br /> | title = The Best Camera<br /> | image = the_best_camera.png<br /> | titletext = The best camera is the one at L2.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by an AMATEUR PHOTOGRAPHER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> ''The Best Camera Is The One That's With You'' [https://www.goodreads.com/book/show/6921300-the-best-camera-is-the-one-that-s-with-you] is a book by photographer Chase Jarvis, celebrating mobile phone cameras, not for their photographic or technical quality but rather for the fact that you always have it when an interesting subject appears. This is advice often given to novice photographers, sometimes with the slight change &quot;The best camera is the one you use most.&quot; A cheap {{w|Nikon Coolpix}} camera can be better than a professional {{w|Canon EOS}}, simply for the fact it is lightweight enough to be taken on ''every'' voyage you'll make. A fancy expensive camera that isn't at hand for you to use is of no value for taking pictures.<br /> <br /> However, in this case &quot;the best camera&quot; refers to the {{w|James Webb Space Telescope}} (JWST), the spacecraft depicted in the third frame. It can be considered a camera because it takes pictures. The first pictures taken by the telescope were released on 11-12 July 2022, days before this comic was published [https://www.nasa.gov/webbfirstimages]. The pictures from JWST show objects as they were 13 billion years ago, which was unprecedented. The telescope has [https://www.stsci.edu/files/live/sites/www/files/home/jwst/instrumentation/_documents/jwst-pocket-guide.pdf three instruments which can act as &quot;cameras&quot; for imaging,] a fourth {{w|optical spectrometer|spectrometer}}-only instrument, eight {{w|optical filter}}s and six different {{w|f-number}} pupils.<br /> <br /> The title text references {{w|Lagrange Point|Lagrange Point 2}} (L&lt;sub&gt;2&lt;/sub&gt;). The Lagrange Points are a set of five locations which are solutions to the restricted three-body problem, in which one of the three bodies is much less massive than the other two. A low-mass body in one of these locations is able to be stationary relative to the other two bodies with very little fuel needed for trajectory corrections. In this case, the JWST orbits around the L&lt;sub&gt;2&lt;/sub&gt; point of the Earth-Sun system [https://space.stackexchange.com/a/57378 rather than being stationed exactly at it] to avoid shadows from the Earth and Moon that would cause temperature variations in the instrument.[https://www.jwst.nasa.gov/content/observatory/sunshield.html] It avoids the problem the {{w|Hubble Space Telescope}} had orbiting around the Earth, allowing only a short observation window per revolution. The HST could be used for about 55 minutes of every 95-minute orbit for targets not sufficiently above or below the orbital plane.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Each panel features an image of space, with text printed in white at the top of each panel. The first panel says:]<br /> :They say the best camera is the one you have with you.<br /> <br /> :[A panel showing more stars and galaxies visible.]<br /> :It turns out <br /> <br /> :[A panel showing even more stars and galaxies visible. At the center of the panel is an outline drawing in white of the James Webb Space Telescope.]<br /> :they're wrong.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Astronomy]]<br /> [[Category:Telescopes]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2645:_The_Best_Camera&diff=288739 2022-07-14T03:44:34Z

<p>172.70.211.36: /* Explanation */ copyedit</p> <hr /> <div>{{comic<br /> | number = 2645<br /> | date = July 13, 2022<br /> | title = The Best Camera<br /> | image = the_best_camera.png<br /> | titletext = The best camera is the one at L2.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by an AMATEUR PHOTOGRAPHER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> ''The Best Camera Is The One That's With You'' [https://www.goodreads.com/book/show/6921300-the-best-camera-is-the-one-that-s-with-you] is a book by photographer Chase Jarvis, celebrating mobile phone cameras, not for their photographic or technical quality but rather for the fact that you always have it when an interesting subject appears. This is advice often given to novice photographers, sometimes with the slight change &quot;The best camera is the one you use most.&quot; A cheap {{w|Nikon Coolpix}} camera can be better than a professional {{w|Canon EOS}}, simply for the fact it is lightweight enough to be taken on ''every'' voyage you'll make. A fancy expensive camera that isn't at hand for you to use is of no value for taking pictures.<br /> <br /> However, in this case &quot;the best camera&quot; refers to the {{w|James Webb Space Telescope}} (JWST), the spacecraft depicted in the third frame. It can be considered a camera because it takes pictures. The first pictures taken by the telescope were released on 11-12 July 2022, days before this comic was published [https://www.nasa.gov/webbfirstimages]. The pictures from JWST show objects as they were 13 billion years ago, which was unprecedented. The telescope has [https://www.stsci.edu/files/live/sites/www/files/home/jwst/instrumentation/_documents/jwst-pocket-guide.pdf three instruments which can act as &quot;cameras&quot; for imaging,] a fourth {{w|optical spectrometer|spectrometer}} instrument, eight {{w|optical filter}}s and six different {{w|f-number}} pupils.<br /> <br /> The title text references {{w|Lagrange Point|Lagrange Point 2}} (L&lt;sub&gt;2&lt;/sub&gt;). The Lagrange Points are a set of five locations which are solutions to the restricted three-body problem, in which one of the three bodies is much less massive than the other two. A low-mass body in one of these locations is able to be stationary relative to the other two bodies with very little fuel needed for trajectory corrections. In this case, the JWST orbits around the L&lt;sub&gt;2&lt;/sub&gt; point of the Earth-Sun system [https://space.stackexchange.com/a/57378 rather than being stationed exactly at it] to avoid shadows from the Earth and Moon that would cause temperature variations in the instrument.[https://www.jwst.nasa.gov/content/observatory/sunshield.html] It avoids the problem the {{w|Hubble Space Telescope}} had orbiting around the Earth, allowing only a short observation window per revolution. The HST could be used for about 55 minutes of every 95-minute orbit for targets not sufficiently above or below the orbital plane.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Each panel features an image of space, with text printed in white at the top of each panel. The first panel says:]<br /> :They say the best camera is the one you have with you.<br /> <br /> :[A panel showing more stars and galaxies visible.]<br /> :It turns out <br /> <br /> :[A panel showing even more stars and galaxies visible. At the center of the panel is an outline drawing in white of the James Webb Space Telescope.]<br /> :they're wrong.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Astronomy]]<br /> [[Category:Telescopes]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2645:_The_Best_Camera&diff=288738 2022-07-14T03:43:13Z

<p>172.70.211.36: /* Explanation */ fix links</p> <hr /> <div>{{comic<br /> | number = 2645<br /> | date = July 13, 2022<br /> | title = The Best Camera<br /> | image = the_best_camera.png<br /> | titletext = The best camera is the one at L2.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by an AMATEUR PHOTOGRAPHER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> ''The Best Camera Is The One That's With You'' [https://www.goodreads.com/book/show/6921300-the-best-camera-is-the-one-that-s-with-you] is a book by photographer Chase Jarvis, celebrating mobile phone cameras, not for their photographic or technical quality but rather for the fact that you always have it when an interesting subject appears. This is advice often given to novice photographers, sometimes with the slight change &quot;The best camera is the one you use most.&quot; A cheap {{w|Nikon Coolpix}} camera can be better than a professional {{w|Canon EOS}}, simply for the fact it is lightweight enough to be taken on ''every'' voyage you'll make. A fancy expensive camera that isn't at hand for you to use is of no value for taking pictures.<br /> <br /> However, in this case &quot;the best camera&quot; refers to the {{w|James Webb Space Telescope}} (JWST), the spacecraft depicted in the third frame. It can be considered a camera because it takes pictures. The first pictures taken by the telescope were released on 11-12 July 2022, days before this comic was published [https://www.nasa.gov/webbfirstimages]. The pictures from JWST show objects as they were 13 billion years ago, which was unprecedented. The telescope has [https://www.stsci.edu/files/live/sites/www/files/home/jwst/instrumentation/_documents/jwst-pocket-guide.pdf three instruments which can act as &quot;cameras&quot; for imaging], along with a fourth which is only a {{w|optical spectrometer|spectrometer}}, along with eight {{w|optical filter}}s and six different {{w|f-number}} pupils.<br /> <br /> The title text references {{w|Lagrange Point|Lagrange Point 2}} (L&lt;sub&gt;2&lt;/sub&gt;). The Lagrange Points are a set of five locations which are solutions to the restricted three-body problem, in which one of the three bodies is much less massive than the other two. A low-mass body in one of these locations is able to be stationary relative to the other two bodies with very little fuel needed for trajectory corrections. In this case, the JWST orbits around the L&lt;sub&gt;2&lt;/sub&gt; point of the Earth-Sun system [https://space.stackexchange.com/a/57378 rather than being stationed exactly at it] to avoid shadows from the Earth and Moon that would cause temperature variations in the instrument.[https://www.jwst.nasa.gov/content/observatory/sunshield.html] It avoids the problem the {{w|Hubble Space Telescope}} had orbiting around the Earth, allowing only a short observation window per revolution. The HST could be used for about 55 minutes of every 95-minute orbit for targets not sufficiently above or below the orbital plane.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Each panel features an image of space, with text printed in white at the top of each panel. The first panel says:]<br /> :They say the best camera is the one you have with you.<br /> <br /> :[A panel showing more stars and galaxies visible.]<br /> :It turns out <br /> <br /> :[A panel showing even more stars and galaxies visible. At the center of the panel is an outline drawing in white of the James Webb Space Telescope.]<br /> :they're wrong.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Astronomy]]<br /> [[Category:Telescopes]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2645:_The_Best_Camera&diff=288737 2022-07-14T03:41:47Z

<p>172.70.211.36: /* Explanation */ camera specs</p> <hr /> <div>{{comic<br /> | number = 2645<br /> | date = July 13, 2022<br /> | title = The Best Camera<br /> | image = the_best_camera.png<br /> | titletext = The best camera is the one at L2.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by an AMATEUR PHOTOGRAPHER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> ''The Best Camera Is The One That's With You'' [https://www.goodreads.com/book/show/6921300-the-best-camera-is-the-one-that-s-with-you] is a book by photographer Chase Jarvis, celebrating mobile phone cameras, not for their photographic or technical quality but rather for the fact that you always have it when an interesting subject appears. This is advice often given to novice photographers, sometimes with the slight change &quot;The best camera is the one you use most.&quot; A cheap {{w|Nikon Coolpix}} camera can be better than a professional {{w|Canon EOS}}, simply for the fact it is lightweight enough to be taken on ''every'' voyage you'll make. A fancy expensive camera that isn't at hand for you to use is of no value for taking pictures.<br /> <br /> However, in this case &quot;the best camera&quot; refers to the {{w|James Webb Space Telescope}} (JWST), the spacecraft depicted in the third frame. It can be considered a camera because it takes pictures. The first pictures taken by the telescope were released on 11-12 July 2022, days before this comic was published [https://www.nasa.gov/webbfirstimages]. The pictures from JWST show objects as they were 13 billion years ago, which was unprecedented. The telescope has [https://www.stsci.edu/files/live/sites/www/files/home/jwst/instrumentation/_documents/jwst-pocket-guide.pdf three instruments which can act as &quot;cameras&quot; for imaging], along with a fourth which is only a {{w|spectrograph}}, along with eight {{w|optical filter}}s and six {{w|f-stop}} pupils.<br /> <br /> The title text references {{w|Lagrange Point|Lagrange Point 2}} (L&lt;sub&gt;2&lt;/sub&gt;). The Lagrange Points are a set of five locations which are solutions to the restricted three-body problem, in which one of the three bodies is much less massive than the other two. A low-mass body in one of these locations is able to be stationary relative to the other two bodies with very little fuel needed for trajectory corrections. In this case, the JWST orbits around the L&lt;sub&gt;2&lt;/sub&gt; point of the Earth-Sun system [https://space.stackexchange.com/a/57378 rather than being stationed exactly at it] to avoid shadows from the Earth and Moon that would cause temperature variations in the instrument.[https://www.jwst.nasa.gov/content/observatory/sunshield.html] It avoids the problem the {{w|Hubble Space Telescope}} had orbiting around the Earth, allowing only a short observation window per revolution. The HST could be used for about 55 minutes of every 95-minute orbit for targets not sufficiently above or below the orbital plane.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Each panel features an image of space, with text printed in white at the top of each panel. The first panel says:]<br /> :They say the best camera is the one you have with you.<br /> <br /> :[A panel showing more stars and galaxies visible.]<br /> :It turns out <br /> <br /> :[A panel showing even more stars and galaxies visible. At the center of the panel is an outline drawing in white of the James Webb Space Telescope.]<br /> :they're wrong.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Astronomy]]<br /> [[Category:Telescopes]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2645:_The_Best_Camera&diff=288734 2022-07-13T23:25:11Z

<p>172.70.211.36: /* Explanation */ move link</p> <hr /> <div>{{comic<br /> | number = 2645<br /> | date = July 13, 2022<br /> | title = The Best Camera<br /> | image = the_best_camera.png<br /> | titletext = The best camera is the one at L2.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by an AMATEUR PHOTOGRAPHER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> ''The Best Camera Is The One That's With You'' [https://www.goodreads.com/book/show/6921300-the-best-camera-is-the-one-that-s-with-you] is a book by photographer Chase Jarvis, celebrating mobile phone cameras, not for their photographic or technical quality but rather for the fact that you always have it when an interesting subject appears. This is advice often given to novice photographers, sometimes with the slight change &quot;The best camera is the one you use most.&quot; A cheap {{w|Nikon Coolpix}} camera can be better than a professional {{w|Canon EOS}}, simply for the fact it is lightweight enough to be taken on ''every'' voyage you'll make. A fancy expensive camera that isn't at hand for you to use is of no value for taking pictures.<br /> <br /> However, in this case &quot;the best camera&quot; refers to the {{w|James Webb Space Telescope}} (JWST), the spacecraft depicted in the third frame. It can be considered a camera because it takes pictures. The first pictures taken by the telescope were released on 11-12 July 2022, days before this comic was published [https://www.nasa.gov/webbfirstimages]. The pictures from JWST show objects as they were 13 billion years ago, which was unprecedented. The title text references {{w|Lagrange Point|Lagrange Point 2}} (L&lt;sub&gt;2&lt;/sub&gt;), one of the five places in space where something can be stationary relative to two celestial bodies (here, Earth and Sun), and which the JWST revolves around. The Sun-Earth L&lt;sub&gt;2&lt;/sub&gt; point was chosen for JWST because orbiting a Lagrange point uses very little fuel for trajectory corrections, and it avoids the problem the {{w|Hubble Space Telescope}} had orbiting around the Earth, allowing only a short observation window per revolution. The HST could be used for about 55 minutes of every 95-minute orbit for targets not sufficiently above or below the orbital plane. In addition, [https://space.stackexchange.com/a/57378 the telescope orbits around L&lt;sub&gt;2&lt;/sub&gt; rather than being stationed exactly at it] to avoid shadows from the Earth and Moon that would cause temperature variations in the instrument.[https://www.jwst.nasa.gov/content/observatory/sunshield.html]<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Each panel features an image of space, with text printed in white at the top of each panel. The first panel says:]<br /> :They say the best camera is the one you have with you.<br /> <br /> :[A panel showing more stars and galaxies visible.]<br /> :It turns out <br /> <br /> :[A panel showing even more stars and galaxies visible. At the center of the panel is an outline drawing in white of the James Webb Space Telescope.]<br /> :they're wrong.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Astronomy]]<br /> [[Category:Telescopes]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2645:_The_Best_Camera&diff=288733 2022-07-13T23:23:19Z

<p>172.70.211.36: /* Explanation */ link showing JWST orbit, grammar</p> <hr /> <div>{{comic<br /> | number = 2645<br /> | date = July 13, 2022<br /> | title = The Best Camera<br /> | image = the_best_camera.png<br /> | titletext = The best camera is the one at L2.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by an AMATEUR PHOTOGRAPHER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> ''The Best Camera Is The One That's With You'' [https://www.goodreads.com/book/show/6921300-the-best-camera-is-the-one-that-s-with-you] is a book by photographer Chase Jarvis, celebrating mobile phone cameras, not for their photographic or technical quality but rather for the fact that you always have it when an interesting subject appears. This is advice often given to novice photographers, sometimes with the slight change &quot;The best camera is the one you use most.&quot; A cheap {{w|Nikon Coolpix}} camera can be better than a professional {{w|Canon EOS}}, simply for the fact it is lightweight enough to be taken on ''every'' voyage you'll make. A fancy expensive camera that isn't at hand for you to use is of no value for taking pictures.<br /> <br /> However, in this case &quot;the best camera&quot; refers to the {{w|James Webb Space Telescope}} (JWST), the spacecraft depicted in the third frame. It can be considered a camera because it takes pictures. The first pictures taken by the telescope were released on 11-12 July 2022, days before this comic was published [https://www.nasa.gov/webbfirstimages]. The pictures from JWST show objects as they were 13 billion years ago, which was unprecedented. The title text references {{w|Lagrange Point|Lagrange Point 2}} (L&lt;sub&gt;2&lt;/sub&gt;), one of the five places in space where something can be stationary relative to two celestial bodies (here, Earth and Sun), and which [https://space.stackexchange.com/a/57378 the JWST revolves around.] The Sun-Earth L&lt;sub&gt;2&lt;/sub&gt; point was chosen for JWST because orbiting a Lagrange point uses very little fuel for trajectory corrections, and it avoids the problem the {{w|Hubble Space Telescope}} had orbiting around the Earth, allowing only a short observation window per revolution. The HST could be used for about 55 minutes of every 95-minute orbit for targets not sufficiently above or below the orbital plane. In addition, the telescope orbits around L&lt;sub&gt;2&lt;/sub&gt;, rather than being stationed exactly at it, to avoid shadows from the Earth and Moon that would cause temperature variations in the instrument.[https://www.jwst.nasa.gov/content/observatory/sunshield.html]<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Each panel features an image of space, with text printed in white at the top of each panel. The first panel says:]<br /> :They say the best camera is the one you have with you.<br /> <br /> :[A panel showing more stars and galaxies visible.]<br /> :It turns out <br /> <br /> :[A panel showing even more stars and galaxies visible. At the center of the panel is an outline drawing in white of the James Webb Space Telescope.]<br /> :they're wrong.<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Astronomy]]<br /> [[Category:Telescopes]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2644:_fMRI_Billboard&diff=288684 2022-07-12T21:52:25Z

<p>172.70.211.36: /* Explanation */ seems like more of an or here</p> <hr /> <div>{{comic<br /> | number = 2644<br /> | date = July 11, 2022<br /> | title = fMRI Billboard<br /> | image = fmri_billboard.png<br /> | titletext = [other side] If the first word of an instruction you're given starts with the same letter as your crush's name, for that step imagine the experimenter is your crush.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by YOUR SCARIEST MEMORY - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> {{w|Functional magnetic resonance imaging}}, or fMRI, is a method of {{w|4DCT|four-dimensional computed tomography}} able to record animated multi-layered images of animal brain activity by detecting blood flow changes apparent from magnetic differences between oxygenated and deoxygenated {{w|hemoglobin}}. Scientists use fMRI to try to detect deception and false memories,[https://www.sciencedirect.com/science/article/pii/S0149763419301873] plan brain surgery,[https://www.sciencedirect.com/science/article/pii/S2213158217303133] and understand the relationship between brain structures and cognition,[https://www.sciencedirect.com/science/article/pii/S0149763419300879] among many other investigations. Volunteer research subjects participate in such studies by laying inside large toroidal scanners and following instructions projected on a screen or played through loudspeakers.<br /> <br /> This comic shows a billboard erected by a neuroscience department in an attempt at sabotaging a rival department's volunteer subject compliance with their fMRI study instructions, by suggesting behaviors which would likely produce unexpected results, such as recalling a frightening memory after seeing similar stimulus slides, or imagining the lab technician is a romantic interest when reading words that begin with the same letter as their name. This is funny because academic department rivalries do not usually lead to sabotage,{{citation needed}} and in the rare cases that they do, it's usually clandestine instead of so absurdly blatant.<br /> <br /> Following such suggestions or even inadvertently remembering them during an fMRI could very well interfere with its results. fMRI experiments are often criticized because they have low {{w|statistical power}} and can easily be confounded by experiment subject error in following instructions, among many other variables. In a famous 2009 study, a dead fish was shown to have apparent evidence of brain activity when scanned with ordinary fMRI techniques.[http://prefrontal.org/files/posters/Bennett-Salmon-2009.pdf] In 2015, discovery of a statistical error invalidated at least 40,000 fMRI studies.[https://www.sciencealert.com/a-bug-in-fmri-software-could-invalidate-decades-of-brain-research-scientists-discover] Subsequently in 2017, many more fMRI results were further discredited due to poor software parameter selection.[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5487467]<br /> <br /> The title text indicates that the sabotaging instructions are printed on both sides of the billboard, suggesting that it might have been erected on the grounds of the targeted rival department. Alternately, the instructions on the other side may be intended to disrupt research in the other institution.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> :[A large, building-sized billboard rises over what appears to be a college campus. It reads:]<br /> : ⚠ Student fMRI volunteers ⚠<br /> : Remember, when you're in the scanner, if you see a slide that's similar to one they already showed you, think as hard as you can about your scariest memory.<br /> <br /> :[Caption below panel:] A rival neuroscience department keeps trying to sabotage our experiments.<br /> <br /> {{comic discussion}}<br /> [[Category: Science]]<br /> [[Category: Psychology]]<br /> [[Category: Biology]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2644:_fMRI_Billboard&diff=288683 2022-07-12T21:51:25Z

<p>172.70.211.36: /* Explanation */ volunteers are almost always human</p> <hr /> <div>{{comic<br /> | number = 2644<br /> | date = July 11, 2022<br /> | title = fMRI Billboard<br /> | image = fmri_billboard.png<br /> | titletext = [other side] If the first word of an instruction you're given starts with the same letter as your crush's name, for that step imagine the experimenter is your crush.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by YOUR SCARIEST MEMORY - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> {{w|Functional magnetic resonance imaging}}, or fMRI, is a method of {{w|4DCT|four-dimensional computed tomography}} able to record animated multi-layered images of animal brain activity by detecting blood flow changes apparent from magnetic differences between oxygenated and deoxygenated {{w|hemoglobin}}. Scientists use fMRI to try to detect deception and false memories,[https://www.sciencedirect.com/science/article/pii/S0149763419301873] plan brain surgery,[https://www.sciencedirect.com/science/article/pii/S2213158217303133] and understand the relationship between brain structures and cognition,[https://www.sciencedirect.com/science/article/pii/S0149763419300879] among many other investigations. Volunteer research subjects participate in such studies by laying inside large toroidal scanners and following instructions projected on a screen and played through loudspeakers.<br /> <br /> This comic shows a billboard erected by a neuroscience department in an attempt at sabotaging a rival department's volunteer subject compliance with their fMRI study instructions, by suggesting behaviors which would likely produce unexpected results, such as recalling a frightening memory after seeing similar stimulus slides, or imagining the lab technician is a romantic interest when reading words that begin with the same letter as their name. This is funny because academic department rivalries do not usually lead to sabotage,{{citation needed}} and in the rare cases that they do, it's usually clandestine instead of so absurdly blatant.<br /> <br /> Following such suggestions or even inadvertently remembering them during an fMRI could very well interfere with its results. fMRI experiments are often criticized because they have low {{w|statistical power}} and can easily be confounded by experiment subject error in following instructions, among many other variables. In a famous 2009 study, a dead fish was shown to have apparent evidence of brain activity when scanned with ordinary fMRI techniques.[http://prefrontal.org/files/posters/Bennett-Salmon-2009.pdf] In 2015, discovery of a statistical error invalidated at least 40,000 fMRI studies.[https://www.sciencealert.com/a-bug-in-fmri-software-could-invalidate-decades-of-brain-research-scientists-discover] Subsequently in 2017, many more fMRI results were further discredited due to poor software parameter selection.[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5487467]<br /> <br /> The title text indicates that the sabotaging instructions are printed on both sides of the billboard, suggesting that it might have been erected on the grounds of the targeted rival department. Alternately, the instructions on the other side may be intended to disrupt research in the other institution.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> :[A large, building-sized billboard rises over what appears to be a college campus. It reads:]<br /> : ⚠ Student fMRI volunteers ⚠<br /> : Remember, when you're in the scanner, if you see a slide that's similar to one they already showed you, think as hard as you can about your scariest memory.<br /> <br /> :[Caption below panel:] A rival neuroscience department keeps trying to sabotage our experiments.<br /> <br /> {{comic discussion}}<br /> [[Category: Science]]<br /> [[Category: Psychology]]<br /> [[Category: Biology]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2644:_fMRI_Billboard&diff=288681 2022-07-12T21:49:09Z

<p>172.70.211.36: /* Explanation */ context</p> <hr /> <div>{{comic<br /> | number = 2644<br /> | date = July 11, 2022<br /> | title = fMRI Billboard<br /> | image = fmri_billboard.png<br /> | titletext = [other side] If the first word of an instruction you're given starts with the same letter as your crush's name, for that step imagine the experimenter is your crush.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by YOUR SCARIEST MEMORY - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> {{w|Functional magnetic resonance imaging}}, or fMRI, is a method of {{w|4DCT|four-dimensional computed tomography}} able to record animated multi-layered images of animal brain activity by detecting blood flow changes apparent from magnetic differences between oxygenated and deoxygenated {{w|hemoglobin}}. Scientists use fMRI to try to detect deception and false memories,[https://www.sciencedirect.com/science/article/pii/S0149763419301873] plan brain surgery,[https://www.sciencedirect.com/science/article/pii/S2213158217303133] and understand the relationship between brain structures and cognition,[https://www.sciencedirect.com/science/article/pii/S0149763419300879] among many other investigations. Human volunteer experiment subjects participate in such studies by laying inside large toroidal scanners and following instructions projected on a screen and played through loudspeakers.<br /> <br /> This comic shows a billboard erected by a neuroscience department in an attempt at sabotaging a rival department's volunteer subject compliance with their fMRI study instructions, by suggesting behaviors which would likely produce unexpected results, such as recalling a frightening memory after seeing similar stimulus slides, or imagining the lab technician is a romantic interest when reading words that begin with the same letter as their name. This is funny because academic department rivalries do not usually lead to sabotage,{{citation needed}} and in the rare cases that they do, it's usually clandestine instead of so absurdly blatant.<br /> <br /> Following such suggestions or even inadvertently remembering them during an fMRI could very well interfere with its results. fMRI experiments are often criticized because they have low {{w|statistical power}} and can easily be confounded by experiment subject error in following instructions, among many other variables. In a famous 2009 study, a dead fish was shown to have apparent evidence of brain activity when scanned with ordinary fMRI techniques.[http://prefrontal.org/files/posters/Bennett-Salmon-2009.pdf] In 2015, discovery of a statistical error invalidated at least 40,000 fMRI studies.[https://www.sciencealert.com/a-bug-in-fmri-software-could-invalidate-decades-of-brain-research-scientists-discover] Subsequently in 2017, many more fMRI results were further discredited due to poor software parameter selection.[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5487467]<br /> <br /> The title text indicates that the sabotaging instructions are printed on both sides of the billboard, suggesting that it might have been erected on the grounds of the targeted rival department. Alternately, the instructions on the other side may be intended to disrupt research in the other institution.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> :[A large, building-sized billboard rises over what appears to be a college campus. It reads:]<br /> : ⚠ Student fMRI volunteers ⚠<br /> : Remember, when you're in the scanner, if you see a slide that's similar to one they already showed you, think as hard as you can about your scariest memory.<br /> <br /> :[Caption below panel:] A rival neuroscience department keeps trying to sabotage our experiments.<br /> <br /> {{comic discussion}}<br /> [[Category: Science]]<br /> [[Category: Psychology]]<br /> [[Category: Biology]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2644:_fMRI_Billboard&diff=288657 2022-07-12T06:02:39Z

<p>172.70.211.36: /* Transcript */ ce</p> <hr /> <div>{{comic<br /> | number = 2644<br /> | date = July 11, 2022<br /> | title = fMRI Billboard<br /> | image = fmri_billboard.png<br /> | titletext = [other side] If the first word of an instruction you're given starts with the same letter as your crush's name, for that step imagine the experimenter is your crush.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by YOUR SCARIEST MEMORY - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> {{w|Functional magnetic resonance imaging}}, or fMRI, is a method of {{w|4DCT|four-dimensional computed tomography}} able to record animated images of animal brain activity by detecting blood flow changes apparent from magnetic differences between oxygenated and deoxygenated {{w|hemoglobin}}. Researchers use fMRI to try to detect deception and false memories,[https://www.sciencedirect.com/science/article/pii/S0149763419301873] plan brain surgery,[https://www.sciencedirect.com/science/article/pii/S2213158217303133] and understand the relationship between brain structures and cognition,[https://www.sciencedirect.com/science/article/pii/S0149763419300879] among many other investigations.<br /> <br /> This comic shows a billboard erected by a neuroscience department in an attempt at sabotaging a rival department's volunteer subject compliance with their fMRI study instructions, by suggesting behaviors which would likely produce unexpected results, such as recalling a frightening memory after seeing similar stimulus slides, or imaging the lab technician is a romantic interest when reading words that begin with the same letter as their name. This is funny because following such instructions, or even inadvertently remembering them during an fMRI, could very well interfere with its results.<br /> <br /> fMRI experiments are often criticized because they have low {{w|statistical power}} and can easily be confounded by experiment subject error in following instructions, among many other variables. In a famous 2009 study, a dead fish was shown to have apparent evidence of brain activity when scanned with ordinary fMRI techniques.[http://prefrontal.org/files/posters/Bennett-Salmon-2009.pdf] In 2015, discovery of a statistical error invalidated at least 40,000 fMRI studies.[https://www.sciencealert.com/a-bug-in-fmri-software-could-invalidate-decades-of-brain-research-scientists-discover] Subsequently in 2017, many more fMRI results were further discredited due to poor software parameter selection.[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5487467]<br /> <br /> The title text indicates that the sabotaging instructions are printed on both sides of the billboard, suggesting that it might have been erected on the grounds of the targeted rival department.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> :[A giant, building-sized billboard rises over what appears to be a college campus. It reads:]<br /> : ⚠ Student fMRI volunteers ⚠<br /> : Remember, when you're in the scanner, if you see a slide that's similar to one they already showed you, think as hard as you can about your scariest memory.<br /> <br /> :[Caption below the panel:] A rival neuroscience department keeps trying to sabotage our experiments.<br /> <br /> {{comic discussion}}<br /> [[Category: Science]]<br /> [[Category: Psychology]]<br /> [[Category: Biology]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=Talk:2643:_Cosmologist_Gift&diff=288617 2022-07-11T22:30:19Z

<p>172.70.211.36: Comment</p> <hr /> <div>&lt;!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--&gt;<br /> - The explanation mentions “Eight zeptograms” although Randall’s box says “4 zeptograms of dark matter.”<br /> <br /> - The 4,800 daltons in the explanation is roughly the size of a small protein; for example, insulin is about 5,800 daltons.<br /> <br /> - Randall’s box says it contains 4 zeptograms of dark matter. Could someone explain this? My incomplete (biologist’s) understanding of dark matter is that astrophysicists do not yet know what it is. So how could Randall claim the box contains 4 zeptograms of it?<br /> <br /> Thanks!<br /> <br /> :Fixed; thank you. [[Special:Contributions/172.70.210.125|172.70.210.125]] 01:18, 9 July 2022 (UTC)<br /> <br /> [https://arxiv.org/abs/2204.09143 Here's] a more recent PBH DM source than those already cited which could comport with Randall's 0.4% DM particles implication, but doesn't do so explicitly. [[Special:Contributions/172.70.206.213|172.70.206.213]] 02:35, 9 July 2022 (UTC)<br /> :With the math corrected per 162.158.134.89 below, the figure is 34% ubiquitous particles. [[Special:Contributions/172.70.211.36|172.70.211.36]] 09:44, 9 July 2022 (UTC)<br /> <br /> And this comic was the perfect birthday gift for me. [[Special:Contributions/108.162.245.203|108.162.245.203]] 02:42, 9 July 2022 (UTC)<br /> <br /> * How was the 23,000 neutrinos/m³ figure obtained? A flux of 7e10/(s·cm²), or 7e14/(s·m²), at a speed of close to 3e8 m/s, gives 2.3e6/m³. That would correspond to a box size of about 0.013 m³, or a bit larger than a typical shoe box. [[Special:Contributions/162.158.134.89|162.158.134.89]] 07:19, 9 July 2022 (UTC)<br /> ::Corrected. [[Special:Contributions/172.70.211.52|172.70.211.52]] 09:40, 9 July 2022 (UTC)<br /> <br /> To note {and I've summarised in an edit) that photons from the Sun can have been travelling for 100,000 years from its core to space, before their 8ish minute trip to the box (assuming you let them in, e.g. leave the lid off, or filter out all but the hard X-rays/etc), whilst neutrinos hardly notice so are 8 or 9 minutes old (before being adjusted for time dilation) regardless. And you can still put as much lead-lined wrapping paper on your present as you want, to keep it a surprise! [[Special:Contributions/172.69.79.211|172.69.79.211]] 14:45, 9 July 2022 (UTC)<br /> :I saw your very interesting source was from 1997 and mostly about neutrino cycles -- which surprisingly match the menstrual cycle better than the orbit of the moon does -- but not mostly about energy migration out of the sun. It looks like the sun actually has multiple layers that engage in different forms of energy transformation. I added a link to the radiative zone (where gamma rays spend 171 thousand years colliding with matter, getting longer wavelength at each collision, until they leave) but somebody should probably learn about all the different zones at some point and make sure the text is correct. I never knew the sun was so complex! I partly imagine high-energy ancient civilizations somewhere deep inside, having their own forms of night and day and seasons. [[Special:Contributions/162.158.62.23|162.158.62.23]] 14:44, 10 July 2022 (UTC)<br /> :I took the [https://news.stanford.edu/pr/97/971219neutrino.html 28 day neutrino cycles] link out, because it really doesn't help explain anything in the comic, and was out of place and confusing where it appeared. [[Special:Contributions/162.158.166.41|162.158.166.41]] 17:20, 11 July 2022 (UTC)<br /> <br /> I don't see how the box containing dark matter is at all consistent with the premise of dark matter being primordial black holes. PBHs wouldn't be ubiquitously distributed through space such that any given volume contains a constant tiny number of them, would they? Black holes that are ''that'' tiny would have evaporated long ago by Hawking radiation, by my understanding. [[User:BunsenH|BunsenH]] ([[User talk:BunsenH|talk]]) 17:26, 11 July 2022 (UTC)<br /> :If dark matter was 100% particles, then a volume on Earth containing 30,000 solar neutrinos would have 12 zeptograms of dark matter, not 4. Since the box is labeled with only a third as much dark matter, the implication is that Randall might think some is clustered in MACHOs. (I'm going to ignore modified gravity, which gets more attention than non-PBH MACHOs but way less than PBHs, and has some foundational issues along with zero successful simulations compared to very successful large-scale simulations using generalized DM.) In the past decade the only MACHO DM theory with more than a handful of papers per year is PBHs, which skyrocketed in popularity after LIGO/Virgo, but are still less popular among mainstream cosmologists than 100% WIMPs. The elephant in the room is that there's lots of evidence for intermediate mass black holes (LIGO/Virgo being the most compelling, but recent indirect observations exist too) but only one out of about thirty WIMP detector experiments have painfully meager positive results, which nobody else has been able to replicate. It's been a similar situation for almost four decades now. Back in the mid-1970s dark matter was assumed to be mostly 100,000 solar mass black holes. A couple generations of constraints assuming monochromatic mass suggested it was a particle instead. But all the constraints, including microlensing, which assume all black holes have even approximately similar masses had to be rejected after the LIGO/Virgo results.<br /> :To answer your question about the sizes, assuming [https://3iom3142cnb81rlnt6w4mtlr-wpengine.netdna-ssl.com/wp-content/uploads/2020/09/08-GW190521-Mass-Plot-Graveyard.png LIGO/Virgo's 3-160 solar mass range] is representative of typical black holes and likely contains their median is kind of unavoidable at this point. If the median is 50 solar masses and all dark matter is black holes, that would work out to around one per star.<br /> :The group to watch [https://iopscience.iop.org/article/10.3847/1538-4357/ac332d/meta as JWST's first light comes in is Yale's,] who propose specific testable hypotheses for its deep IR source count distribution, and use a [https://twitter.com/SheerPriya/status/1472352431468003328 non-monochromatic (platycurtic) mass distribution] for black holes, which is the only correct choice for merging bodies. Specifically, NASA is releasing a [https://www.nasa.gov/feature/goddard/2022/nasa-shares-list-of-cosmic-targets-for-webb-telescope-s-first-images/ SMACS 0723 field] from JWST [https://www.nasa.gov/webbfirstimages tomorrow,] which should be able to test [https://twitter.com/SheerPriya/status/1546576050976870400 these predictions.] Another author to keep an eye on as JWST results roll in is [https://iopscience.iop.org/article/10.1088/1361-6633/ac1e31 Bernard Carr] ([https://arxiv.org/pdf/2002.12778.pdf paywall-free preprint]) known for his DM literature reviews over the years, and who has become an ardent PBH DM proponent post-LIGO/Virgo. [[Special:Contributions/162.158.166.235|162.158.166.235]] 20:38, 11 July 2022 (UTC)<br /> :W00T! They decided to do SMACS 0723 first today! https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-delivers-deepest-infrared-image-of-universe-yet A gift to cosmologists indeed! [[Special:Contributions/172.70.210.233|172.70.210.233]] 22:23, 11 July 2022 (UTC)</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=Talk:2643:_Cosmologist_Gift&diff=288616 2022-07-11T22:29:11Z

<p>172.70.211.36: DIrect link</p> <hr /> <div>&lt;!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--&gt;<br /> - The explanation mentions “Eight zeptograms” although Randall’s box says “4 zeptograms of dark matter.”<br /> <br /> - The 4,800 daltons in the explanation is roughly the size of a small protein; for example, insulin is about 5,800 daltons.<br /> <br /> - Randall’s box says it contains 4 zeptograms of dark matter. Could someone explain this? My incomplete (biologist’s) understanding of dark matter is that astrophysicists do not yet know what it is. So how could Randall claim the box contains 4 zeptograms of it?<br /> <br /> Thanks!<br /> <br /> :Fixed; thank you. [[Special:Contributions/172.70.210.125|172.70.210.125]] 01:18, 9 July 2022 (UTC)<br /> <br /> [https://arxiv.org/abs/2204.09143 Here's] a more recent PBH DM source than those already cited which could comport with Randall's 0.4% DM particles implication, but doesn't do so explicitly. [[Special:Contributions/172.70.206.213|172.70.206.213]] 02:35, 9 July 2022 (UTC)<br /> :With the math corrected per 162.158.134.89 below, the figure is 34% ubiquitous particles. [[Special:Contributions/172.70.211.36|172.70.211.36]] 09:44, 9 July 2022 (UTC)<br /> <br /> And this comic was the perfect birthday gift for me. [[Special:Contributions/108.162.245.203|108.162.245.203]] 02:42, 9 July 2022 (UTC)<br /> <br /> * How was the 23,000 neutrinos/m³ figure obtained? A flux of 7e10/(s·cm²), or 7e14/(s·m²), at a speed of close to 3e8 m/s, gives 2.3e6/m³. That would correspond to a box size of about 0.013 m³, or a bit larger than a typical shoe box. [[Special:Contributions/162.158.134.89|162.158.134.89]] 07:19, 9 July 2022 (UTC)<br /> ::Corrected. [[Special:Contributions/172.70.211.52|172.70.211.52]] 09:40, 9 July 2022 (UTC)<br /> <br /> To note {and I've summarised in an edit) that photons from the Sun can have been travelling for 100,000 years from its core to space, before their 8ish minute trip to the box (assuming you let them in, e.g. leave the lid off, or filter out all but the hard X-rays/etc), whilst neutrinos hardly notice so are 8 or 9 minutes old (before being adjusted for time dilation) regardless. And you can still put as much lead-lined wrapping paper on your present as you want, to keep it a surprise! [[Special:Contributions/172.69.79.211|172.69.79.211]] 14:45, 9 July 2022 (UTC)<br /> :I saw your very interesting source was from 1997 and mostly about neutrino cycles -- which surprisingly match the menstrual cycle better than the orbit of the moon does -- but not mostly about energy migration out of the sun. It looks like the sun actually has multiple layers that engage in different forms of energy transformation. I added a link to the radiative zone (where gamma rays spend 171 thousand years colliding with matter, getting longer wavelength at each collision, until they leave) but somebody should probably learn about all the different zones at some point and make sure the text is correct. I never knew the sun was so complex! I partly imagine high-energy ancient civilizations somewhere deep inside, having their own forms of night and day and seasons. [[Special:Contributions/162.158.62.23|162.158.62.23]] 14:44, 10 July 2022 (UTC)<br /> :I took the [https://news.stanford.edu/pr/97/971219neutrino.html 28 day neutrino cycles] link out, because it really doesn't help explain anything in the comic, and was out of place and confusing where it appeared. [[Special:Contributions/162.158.166.41|162.158.166.41]] 17:20, 11 July 2022 (UTC)<br /> <br /> I don't see how the box containing dark matter is at all consistent with the premise of dark matter being primordial black holes. PBHs wouldn't be ubiquitously distributed through space such that any given volume contains a constant tiny number of them, would they? Black holes that are ''that'' tiny would have evaporated long ago by Hawking radiation, by my understanding. [[User:BunsenH|BunsenH]] ([[User talk:BunsenH|talk]]) 17:26, 11 July 2022 (UTC)<br /> :If dark matter was 100% particles, then a volume on Earth containing 30,000 solar neutrinos would have 12 zeptograms of dark matter, not 4. Since the box is labeled with only a third as much dark matter, the implication is that Randall might think some is clustered in MACHOs. (I'm going to ignore modified gravity, which gets more attention than non-PBH MACHOs but way less than PBHs, and has some foundational issues along with zero successful simulations compared to very successful large-scale simulations using generalized DM.) In the past decade the only MACHO DM theory with more than a handful of papers per year is PBHs, which skyrocketed in popularity after LIGO/Virgo, but are still less popular among mainstream cosmologists than 100% WIMPs. The elephant in the room is that there's lots of evidence for intermediate mass black holes (LIGO/Virgo being the most compelling, but recent indirect observations exist too) but only one out of about thirty WIMP detector experiments have painfully meager positive results, which nobody else has been able to replicate. It's been a similar situation for almost four decades now. Back in the mid-1970s dark matter was assumed to be mostly 100,000 solar mass black holes. A couple generations of constraints assuming monochromatic mass suggested it was a particle instead. But all the constraints, including microlensing, which assume all black holes have even approximately similar masses had to be rejected after the LIGO/Virgo results.<br /> :To answer your question about the sizes, assuming [https://3iom3142cnb81rlnt6w4mtlr-wpengine.netdna-ssl.com/wp-content/uploads/2020/09/08-GW190521-Mass-Plot-Graveyard.png LIGO/Virgo's 3-160 solar mass range] is representative of typical black holes and likely contains their median is kind of unavoidable at this point. If the median is 50 solar masses and all dark matter is black holes, that would work out to around one per star.<br /> :The group to watch [https://iopscience.iop.org/article/10.3847/1538-4357/ac332d/meta as JWST's first light comes in is Yale's,] who propose specific testable hypotheses for its deep IR source count distribution, and use a [https://twitter.com/SheerPriya/status/1472352431468003328 non-monochromatic (platycurtic) mass distribution] for black holes, which is the only correct choice for merging bodies. Specifically, NASA is releasing a [https://www.nasa.gov/feature/goddard/2022/nasa-shares-list-of-cosmic-targets-for-webb-telescope-s-first-images/ SMACS 0723 field] from JWST [https://www.nasa.gov/webbfirstimages tomorrow,] which should be able to test [https://twitter.com/SheerPriya/status/1546576050976870400 these predictions.] Another author to keep an eye on as JWST results roll in is [https://iopscience.iop.org/article/10.1088/1361-6633/ac1e31 Bernard Carr] ([https://arxiv.org/pdf/2002.12778.pdf paywall-free preprint]) known for his DM literature reviews over the years, and who has become an ardent PBH DM proponent post-LIGO/Virgo. [[Special:Contributions/162.158.166.235|162.158.166.235]] 20:38, 11 July 2022 (UTC)<br /> :W00T! They decided to do SMACS 0723 first today! https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-delivers-deepest-infrared-image-of-universe-yet [[Special:Contributions/172.70.210.233|172.70.210.233]] 22:23, 11 July 2022 (UTC)</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=explain_xkcd_talk:Editor_FAQ&diff=288572 2022-07-11T01:29:54Z

<p>172.70.211.36: /* Please do not use semicolon-lines as &quot;headings&quot; */ reply</p> <hr /> <div>Feel free to enter any question about editing this Wiki and don't forget to sign you comment. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 21:18, 31 May 2018 (UTC)<br /> <br /> == Formatting of explanations ==<br /> <br /> Many pages contain tables where a definition list would be 1) easier to read 2) mobile friendly, for example: [https://www.explainxkcd.com/wiki/index.php?title=1957:_2018_CVE_List&amp;oldid=160469 1957]. <br /> <br /> I was also involved in rewriting the transcript for [[1963]], where the discussion came up about how those should be styled. (&quot;as if you were reading the comic to someone&quot;)<br /> <br /> I think we should have a small style guide to encourage sane formatting. What else should such guidelines contain? <br /> <br /> Edit: One more thing I'd love to see: semantic headlines (i.e. &lt; h3&gt; headlines for explanation subchapters instead of &lt; h2&gt; which is the same level as the explanation itself)<br /> <br /> &lt;small&gt;(Sidenote: I've been active on explainxkcd for quite some time, but only now got around making an account.)&lt;/small&gt; [[User:Gir|//gir.st/]] ([[User talk:Gir|talk]]) 15:01, 19 August 2018 (UTC)<br /> <br /> :Thanks for your remarks. First: There is no need to start every new sentence at a new line. Tables are meant for small content in all other cases it's bad layout. I recently changed this [[2034: Equations]] to a proper floating text. At the transcript tables should never be used, even when there is a table in the comic image it should be described by text. The guide here was mainly written by me because there was nothing like this here before. Some people already helped and I'm happy for any further remarks to enhance it. And this table issue is definitely one; I just not wanted to be the only (arrogant) layout master. Your help is welcome to write something, otherwise I will do so soon.<br /> :For headlines we don't use HTML-code but WIKI-code. The main headlines are written like this: &lt;nowiki&gt;==Explanation==&lt;/nowiki&gt;, &lt;nowiki&gt;==Transcript==&lt;/nowiki&gt;, and (optional) &lt;nowiki&gt;==Trivia==&lt;/nowiki&gt;. Headlines inside that chapters should be done in this way: &lt;nowiki&gt;;Subtitle&lt;/nowiki&gt;. The preceding semicolon causes the entire line to be rendered in bold. Only when the explanation really needs sub-chapters it can be done by this: &lt;nowiki&gt;===Sub header===&lt;/nowiki&gt; (three equal signs before and after the text). I will put this also into the FAQ.<br /> :Welcome and thanks for helping. PROTIP: Always use the preview button to check the layout before saving. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 13:39, 20 August 2018 (UTC)<br /> ::hi, I'm aware about the headlines and stuff, it was just shorter to write it this way in the comment. I see you started a bit with a styleguide already; I hope I can contribute to it next week, when things cool down at work a bit. //gir.st/, who is to lazy to log in [[Special:Contributions/172.68.51.190|172.68.51.190]] 06:51, 24 August 2018 (UTC)<br /> <br /> So, one more thing, regarding 'What is the proper layout for headers?'. I think we should better use small &lt;code&gt;&lt;nowiki&gt;====headings====&lt;/nowiki&gt;&lt;/code&gt; instead of just description titles (&lt;code&gt;&lt;nowiki&gt;;bold text&lt;/nowiki&gt;&lt;/code&gt;), since it makes the intent clearer. what is your reasoning behind suggesting it the other way round? greetings, [[User:Gir|//gir.st/]] ([[User talk:Gir|talk]]) 14:49, 25 August 2018 (UTC)<br /> :Thanks for your input and of course Wiki markup headers should be valid. I just believe that the simplest way should also be valid for less experienced writers. When a new explanation starts it's often awful and chaotic; giving a simple but effective structure at the beginning helps against this chaos. So, I'm thinking about dividing the section &quot;What is the proper layout for headers?&quot; (it's a question because it's a FAQ) into two subsections:<br /> :*easy: a semicolon, the colon at the following paragraph may be mentioned - but I'm not sure about the colon because it should be ''easy''<br /> :*advanced: &lt;code&gt;&lt;nowiki&gt;===headings===&lt;/nowiki&gt;&lt;/code&gt; if the comic really can be divided into chapters; &lt;code&gt;&lt;nowiki&gt;====headings====&lt;/nowiki&gt;&lt;/code&gt; as a replacement for the semicolon; and &lt;code&gt;&lt;nowiki&gt;==headings==&lt;/nowiki&gt;&lt;/code&gt; is forbidden because it belongs to expl, trnsc, trivia. The semicolon, colon issue should be mentioned here.<br /> :Please consider that there was many chaos in the past and many writers will do their edits without reading this FAQ. So keeping this simple as possible seems to me to be inevitable. And dividing sections by using the semicolon for a header is still much better than many of those tables. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 17:41, 25 August 2018 (UTC)<br /> ::Based on this discussion I edited the current comic here: [http://www.explainxkcd.com/wiki/index.php?title=2037%3A_Supreme_Court_Bracket&amp;type=revision&amp;diff=161880&amp;oldid=161841] and compare it to this former version [http://www.explainxkcd.com/wiki/index.php?title=2037:_Supreme_Court_Bracket&amp;diff=prev&amp;oldid=161841]. Do not focus on the edits, just scroll down to the resulting page.<br /> ::This brought me to another important issue: NO links in a header. At Wikipedia this is also not welcome. This site isn't Wikipedia but in this case I feel this is a good rule. But the TOC (Table of content) is shown in the preview while it's not at the resulting page. The result is preferred but the TOC in the preview may confuse editors here.<br /> ::So, I'm still looking for simple instructions, layouts which advanced people always can enhance.<br /> ::And consider that some editors are probably younger than xkcd is. Not sure about this but there are definitely young people here and I welcome them all. And I'm NOT getting old like Randall sometimes feel, I like to support every editor despite any other background. And this has to be simple on the first place. STOP(I could talk much more) --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 20:49, 25 August 2018 (UTC)<br /> :::Sorry, I missed this. I'd personally go with the &quot;advanced&quot; option, but mentioning both is fine too. Nice work on 2037! Really enjoying our conversations about this, I hope i'm not a bother ;-) [[User:Gir|//gir.st/]] ([[User talk:Gir|talk]]) 11:20, 28 August 2018 (UTC)<br /> OK, after a few days and some more edits (for example see here: [[2035: Dark Matter Candidates]]) I believe this would be the best guide:<br /> *&lt;code&gt;&lt;nowiki&gt;====headings====&lt;/nowiki&gt;&lt;/code&gt; should be preferred because the advantage is that each header has it's own edit button. One other advantage is that the header text will be shown at the summary in the history.<br /> *The semicolon may be used as a preliminary layout for new comics until it's clear of what content the explanation is composed of.<br /> *On more rare circumstances the &lt;code&gt;&lt;nowiki&gt;===headings===&lt;/nowiki&gt;&lt;/code&gt; may divide the explanation into different larger chapters.<br /> *&lt;code&gt;&lt;nowiki&gt;==headings==&lt;/nowiki&gt;&lt;/code&gt; is reserved to the general layout and has not to be used.<br /> And I still oppose to the colon at the beginning of any paragraph at all. Any thoughts? --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 13:17, 29 August 2018 (UTC)<br /> <br /> == Please '''''do not''''' use semicolon-lines as &quot;headings&quot; ==<br /> <br /> Hi, sorry to butt in, but I was going to mention this here anyway after I saw it in the FAQ. Please ''don't'' continue to give this advice to editors:<br /> &lt;blockquote&gt;For headlines you have to use Wiki-style code. The simplest way is a preceding semicolon at the beginning of the line which causes the entire line to be rendered in bold.&lt;ref&gt;§ [[explain xkcd:Editor FAQ#What_is_the_proper_layout_for_headers.3F|What is the proper layout for headers?]] of the [[explain xkcd:Editor FAQ|Editor FAQ]]&lt;/ref&gt;<br /> <br /> ====References====<br /> &lt;references/&gt;<br /> &lt;/blockquote&gt;<br /> <br /> The [[explain xkcd:Editor FAQ#In_which_case_tables_are_meaningful_and_when_not.3F|previous Editor FAQ section]] has it right: in wikicode, the semicolon opens a ''description list'', and will be translated into equivalent HTML. In other words, the wikicode is processed as follows:<br /> {| class=&quot;wikitable&quot;<br /> |-<br /> ! Wikicode !! HTML<br /> |-<br /> | style=&quot;vertical-align:top;&quot; |&lt;pre&gt;; xkcd<br /> : a popular webcomic&lt;/pre&gt;<br /> |&lt;pre&gt;&amp;lt;dl&amp;gt;<br /> &amp;lt;dt&amp;gt;xkcd&amp;lt;/dt&amp;gt;<br /> &amp;lt;dd&amp;gt;a popular webcomic&amp;lt;/dd&amp;gt;<br /> &amp;lt;/dl&amp;gt;&lt;/pre&gt;<br /> |}<br /> <br /> One or more lines started with a semicolon ''must'' be followed by at least one line that starts with a colon, to provide the &lt;code&gt;&amp;lt;dd&amp;gt;...&amp;lt;/dd&amp;gt;&lt;/code&gt; part of the description list block.<br /> <br /> It is a {{w|Help:List#Common_mistakes|common mistake}} to use semicolon-lines as &quot;headings&quot;. Unfortunately the result is '''invalid HTML''', since the HTML spec requires that a &lt;code&gt;&amp;lt;dl&amp;gt;&lt;/code&gt; block contain:<br /> &lt;blockquote&gt;Zero or more groups each consisting of one or more dt elements followed by one or more dd elements&lt;/blockquote&gt;<br /> It's fine to have multiple semicolon-lines in a row (as the HTML standard allows for groups of several &lt;code&gt;&amp;lt;dt&amp;gt;...&amp;lt;/dt&amp;gt;&lt;/code&gt; blocks in sequence), but they must '''always''' be followed by at least one &lt;code&gt;&amp;lt;dd&amp;gt;...&amp;lt;/dd&amp;gt;&lt;/code&gt; block, created in wikicode by following a line started with a semicolon with another line that starts with a colon. <br /> <br /> Just like lines started with &lt;code&gt;*&lt;/code&gt; or &lt;code&gt;#&lt;/code&gt;, a line started with a &lt;code&gt;;&lt;/code&gt; creates a list element, and has syntactic requirements that must be followed. Abusing the description-term wikicode for purposes other than description-list creation not only breaks the HTML on the resulting page, but it makes the content much harder for screen readers and other assistive technologies to parse and accurately reproduce. <br /> <br /> (And, yes, technically Mediawiki's use of &lt;code&gt;:&lt;/code&gt;-lines for indenting, as on talk pages, is also invalid since it creates a &lt;code&gt;&amp;lt;dl&amp;gt;&amp;lt;dd&amp;gt;...&amp;lt;/dd&amp;gt;&amp;lt;/dl&amp;gt;&lt;/code&gt; block with no &lt;code&gt;&amp;lt;dt&amp;gt;&lt;/code&gt; element. So it's bad enough on talk pages, it's 100x worse to encourage doing it on '''article''' pages.) Please consider removing this bad advice from the Editor FAQ. Thanks. -- [[User:FeRDNYC|FeRDNYC]] ([[User talk:FeRDNYC|talk]]) 05:48, 5 September 2018 (UTC)<br /> <br /> :Thanks for your remarks, that's why I started this FAQ and the discussion about it. Especially the header section is still preliminary, just check the section above here at the talk page.<br /> :My first purpose is to keep it as simple as possible for writers having not much or no knowledge about wiki code or HTML. After that an advanced section should follow and define the rules for a complete article.<br /> :Please check my summary from 29 August 2018 just above here. You're right the semicolon isn't a header, that's why I'm saying it should be used only temporary. And after reading your remarks here I would propose a single line with bold text and a following empty line instead of that semicolon thing.<br /> :Keep it simple for people who just want to write something here; advanced users will change it to an appropriate layout later. Consider: When a new comic is out the explanation often starts in chaos. And for now I'm really happy that the overwhelming usage of tables is stopped.<br /> :Let me know what you do think about the bold text line (not by semicolon) and the more sophisticated header guidance for the final layout as I've mentioned on 29 August 2018. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 12:45, 5 September 2018 (UTC)<br /> ::And of course the usage of a semicolon should also be mentioned together with the colon because it's a list. An entire paragraph &quot;How do I format lists?&quot; has still to be written yet. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 12:51, 5 September 2018 (UTC)<br /> ::One more: I've checked the definition for &lt;code&gt;dd/dt/dl&lt;/code&gt; and it's clear the &lt;code&gt;dd&lt;/code&gt; tag must be followed by at least one (either &lt;code&gt;dt&lt;/code&gt; or &lt;code&gt;dl&lt;/code&gt;) child. This tells me that the indent done by a colon is proper HTML. This is very important because every transcript since the first comic uses this indentation. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 13:20, 5 September 2018 (UTC)<br /> :::On one hand, yes, the HTML is technically invalid, but on the other hand, every browser gets the intended layout correct, in no small part because these sorts of errors have been parts of industry-wide regression test suites since the mid-1990s. Asking users to try to achieve completely unnecessary perfection is a waste of time. Even screenreaders are completely unfazed by this nominal flaw. [[Special:Contributions/172.70.211.36|172.70.211.36]] 01:29, 11 July 2022 (UTC)<br /> <br /> ==Incomplete tags==<br /> The FAQ says to use &lt;code&gt;&lt;nowiki&gt;{{incomplete transcript|YOUR REASON}}&lt;/nowiki&gt;&lt;/code&gt; but instead of rendering like this (like with the incomplete template):<br /> <br /> {{notice|'''This transcript is incomplete:''' ''YOUR REASON'' &lt;br/&gt;If you can address this issue, please '''[{{fullurl:{{{target|{{FULLPAGENAME}}}}}|action=edit}} edit the page]!''' Thanks.}}<br /> <br /> It renders like this:<br /> <br /> {{notice|'''This transcript is incomplete.''' Please help [{{fullurl:{{{target|{{FULLPAGENAME}}}}}|action=edit}} editing] it! Thanks.}}<br /> <br /> Can someone please change this? [[Special:Contributions/172.68.133.180|172.68.133.180]] 02:55, 13 October 2018 (UTC)<br /> :The FAQ also says: &quot;The reason at the transcript is not shown to the viewer.&quot; You can see it when you edit the transcript. And because the reason for the comic is also often not given this should be enough for the transcript. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 16:49, 15 October 2018 (UTC)<br /> <br /> == math markup ==<br /> <br /> Just to note - I was curious about the &quot;math markup&quot; message at the top of each page, and duly followed the link to the Editor FAQ as instructed, but ther--e is no mention of why it shouldn't be used... (no account yet, as I've not made any edits - yet! and i use google data saver, so this is not my ip --&gt;) --[[Special:Contributions/162.158.34.22|162.158.34.22]] 23:49, 11 December 2018 (UTC)<br /> <br /> :damn, I'm tired - just re-read the section titles, and there it is. It's late, so sorry! --[[Special:Contributions/162.158.34.22|162.158.34.22]] 23:54, 11 December 2018 (UTC)<br /> <br /> ::I think the reason given is incomplete, but wanted to check here before I amended it. Transcripts are for the benefit of visually-challenged visitors, so using math markup, and thus rendering the text as images, is counterproductive. Right? -- [[User:Dtgriscom|Dtgriscom]] ([[User talk:Dtgriscom|talk]]) 15:06, 20 March 2019 (UTC)<br /> <br /> :::The explanation is (in my opinion) somewhat silly, as the image generated by MathML has an alt tag for text browsers/accessible use. Further, if this wiki's settings were chosen correctly, the image would be output with MathML alongside, which is the ''actual'' (non-plaintext) accessible solution for displaying mathematical formulas on the web. See also: https://accessibility.princeton.edu/about/blog/mathml-accessible-math-markup [[User:DimeCadmium|DimeCadmium]] ([[User talk:DimeCadmium|talk]]) 02:20, 12 October 2019 (UTC)<br /> <br /> == Create page for new comic ==<br /> <br /> Should there be a paragraph about this?<br /> Since the bot is not working anymore, people need to do this. I know I have seen isntructions somewhere on this wiki, but cannot find them... [btw: there is a new comic up, right now, as I post this line, which is not yet in the wiki. SO if you know how to do it, do it before explaining it on the FAQ :)] --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 13:27, 3 January 2020 (UTC)<br /> <br /> == Page targeted by Spam ==<br /> <br /> The page is currently targeted heavily by Spambots. I am not sure why they target this specific page. It might be, because it is linked in the header? Since Admins (who could protect the FAQ) seem to be currently absent from the page, anyone got any ideas what to do about it? leave it to spam and create a seperate FAQ with the same content? --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 10:08, 26 February 2020 (UTC)<br /> <br /> == Spaces ==<br /> <br /> Seriously, why oh why is [[1285:_Third_Way|1285]] not linked into the statement about the one space / two space [[1285:_Third_Way | controversy]]? This feels like an inexplicable gap. Is there a policy insisting the FAQ remain fastidiously humorless in all ways? [[Special:Contributions/162.158.107.231|162.158.107.231]] 02:10, 29 January 2021 (UTC)<br /> <br /> == Duplicating the hover text/title in the transcript section? ==<br /> <br /> Is there a reason not to duplicate the title/hovertext in the transcript section, so a screenreader user can be sent there and not have to page back up for that bit (besides &quot;one or more editors would need to check all entries and edit it in where missing&quot;)? [[Special:Contributions/141.101.68.43|141.101.68.43]] 00:11, 28 November 2021 (UTC)<br /> :For my two (or three) cents:<br /> :1) You'd be duplicating it, so you ought to lose the sub-image record if you do that or you could get silly with all kinds of repeating of everything..<br /> :2) It's a Transcript to try to record/present the text (and imagery) you cannot already screen-read.<br /> :3) It doesn't need manual editing (and manual editing is more likely to have mistakes, anyway).<br /> :...Perhaps some Template(-pair?) could be developed to sit post-template to &quot;display:screenreader-only&quot; (or whatever the markup format would be) the upper-templated titletext field? [[Special:Contributions/172.70.86.12|172.70.86.12]] 04:00, 28 November 2021 (UTC)<br /> <br /> == it's/its typo ==<br /> <br /> At §[[explain_xkcd:Editor_FAQ#How_do_I_enter_mathematical_or_chemical_formulas.3F| How_do_I_enter_mathematical_or_chemical_formulas?]] please change “it's Wikipedia help page” to “'''its''' Wikipedia help page” (for the same reason that &quot;our&quot; and &quot;their&quot; don't have apostrophes).<br /> [[User:Kurahaupo|Kurahaupo]] ([[User talk:Kurahaupo|talk]]) 23:44, 29 January 2022 (UTC)<br /> : Came here to say this, but I see I'm two months too late. [[Special:Contributions/172.70.86.64|172.70.86.64]] 12:32, 9 April 2022 (UTC)</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2643:_Cosmologist_Gift&diff=288545 2022-07-10T00:40:45Z

<p>172.70.211.36: /* Explanation */ clarify</p> <hr /> <div>{{comic<br /> | number = 2643<br /> | date = July 8, 2022<br /> | title = Cosmologist Gift<br /> | image = cosmologist_gift.png<br /> | titletext = These neutrinos were freshly produced by a local source just 8 minutes ago<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a MUON ON SALE, PACKAGED IN A BOX THAT A CAT MIGHT OR MIGHT NOT HAVE DIED IN- Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> This comic shows a box labeled to indicate that it contains 30,000 fresh {{w|neutrino}}s and four zeptograms of {{w|dark matter}}. The box is intended as an inexpensive gift for a {{w|cosmologist}}. The gift giver didn't put those things in the box—both are simply passing through it, so the &quot;gift&quot; consists of exactly what was in the empty space it occupies. While the caption suggests this would be a good gift for a cosmologist, what they or anyone else would do with such a box is uncertain.<br /> <br /> There are about a billion neutrinos per cubic meter throughout space, produced during the {{w|Big Bang}}.[https://physics.mit.edu/news/journal/physicsatmit_14_conrad/] However, the flux of &quot;freshly produced&quot; {{w|solar neutrino}}s at Earth is around 7&amp;times;10&lt;sup&gt;10&lt;/sup&gt;/cm&lt;sup&gt;2&lt;/sup&gt;/s, yielding about 2.3 million per cubic meter, implying the box is around 13 liters, about 80% the size of a typical {{w|breadbox}}.<br /> <br /> Four zeptograms is a minuscule mass, equal to four sextillionths of a gram, or the mass of about 200 carbon-12 atoms. There is an estimated 0.011 to 0.016 {{w|solar mass}}es of dark matter per cubic {{w|parsec}} locally to the solar system,[https://iopscience.iop.org/article/10.1088/1361-6633/ac24e7/meta] about 900 zeptograms per cubic meter, suggesting the box is closer to 4 liters. This discrepancy could imply Randall agrees with cosmologists who believe dark matter is partially composed of {{w|primordial black hole}}s,[https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.121301][https://www.sciencedirect.com/science/article/abs/pii/S2212686418301250?via%3Dihub][https://news.yale.edu/2021/12/16/black-holes-and-dark-matter-are-they-one-and-same][https://iopscience.iop.org/article/10.3847/2041-8205/823/2/L25][https://iopscience.iop.org/article/10.1088/1475-7516/2010/04/023] instead of being entirely composed of pervasive subatomic particles. A billion neutrinos have a mass of only about 2×10&lt;sup&gt;-12&lt;/sup&gt; zeptograms, at about 0.1 {{w|electron volt}}s each.<br /> <br /> The &quot;local source&quot; mentioned in the title text is a pun on the commercial value of fresh, locally produced items, but the comic means the Sun. It takes neutrinos not much more than 8 minutes to reach Earth once they're emitted, roughly the same time as photons. (This doesn't take into account that photons additionally take [https://news.stanford.edu/pr/97/971219neutrino.html a hundred thousand years to reach the Sun's surface] from the core where they're generated.) However, as the neutrinos have been travelling at more than 99.999% of the speed of light, they will have aged by less than two seconds,[https://www.omnicalculator.com/physics/time-dilation] and so are technically even fresher.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[A picture of a box with writing on one side, saying as follows:]<br /> <br /> :30,000 neutrinos<br /> :&lt;small&gt;Freshly produced&lt;/small&gt;<br /> :Plus 4 zeptograms of dark matter<br /> <br /> :[Caption below the panel]: <br /> :Cosmologists are easy to shop for because you can just get them a box.<br /> <br /> {{comic discussion}}<br /> [[Category:Astronomy]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2643:_Cosmologist_Gift&diff=288543 2022-07-10T00:26:09Z

<p>172.70.211.36: real</p> <hr /> <div>{{comic<br /> | number = 2643<br /> | date = July 8, 2022<br /> | title = Cosmologist Gift<br /> | image = cosmologist_gift.png<br /> | titletext = These neutrinos were freshly produced by a local source just 8 minutes ago<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a MUON ON SALE, PACKAGED IN A BOX THAT A CAT MIGHT OR MIGHT NOT HAVE DIED IN- Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> This comic shows a box labeled to indicate that it contains 30,000 fresh {{w|neutrino}}s and four zeptograms of {{w|dark matter}}. The box is intended as an inexpensive gift for a {{w|cosmologist}}. The gift giver didn't put those things in the box—both are simply passing through it, so the &quot;gift&quot; consists of exactly what was in the empty space it occupies. While the caption suggests this would be a good gift for a cosmologist, what they or anyone else would do with such a box is uncertain.<br /> <br /> There are about a billion neutrinos per cubic meter throughout space, produced during the {{w|Big Bang}}.[https://physics.mit.edu/news/journal/physicsatmit_14_conrad/] However, the flux of &quot;freshly produced&quot; {{w|solar neutrino}}s at Earth is around 7&amp;times;10&lt;sup&gt;10&lt;/sup&gt;/cm&lt;sup&gt;2&lt;/sup&gt;/s, yielding about 2.3 million per cubic meter, implying the box is around 13 liters, about 80% the size of a typical {{w|breadbox}}.<br /> <br /> Four zeptograms is a minuscule mass, equal to four sextillionths of a gram, or the mass of about 200 carbon-12 atoms. There is an estimated 0.011 to 0.016 {{w|solar mass}}es of dark matter per cubic {{w|parsec}} locally to the solar system,[https://iopscience.iop.org/article/10.1088/1361-6633/ac24e7/meta] about 900 zeptograms per cubic meter, suggesting the box is closer to 4 liters. This discrepancy could imply Randall agrees with cosmologists who believe dark matter is partially composed of {{w|primordial black hole}}s,[https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.121301][https://www.sciencedirect.com/science/article/abs/pii/S2212686418301250?via%3Dihub][https://news.yale.edu/2021/12/16/black-holes-and-dark-matter-are-they-one-and-same][https://iopscience.iop.org/article/10.3847/2041-8205/823/2/L25][https://iopscience.iop.org/article/10.1088/1475-7516/2010/04/023] instead of being entirely composed of pervasive subatomic particles. A billion neutrinos have a mass of only about 2×10&lt;sup&gt;-12&lt;/sup&gt; zeptograms, at about 0.1 {{w|electron volt}}s each.<br /> <br /> The &quot;local source&quot; mentioned in the title text is a pun on the commercial value of fresh, locally produced items, but here it is the Sun. It takes neutrinos not much more than 8 minutes to reach Earth once they're emitted, roughly the same time as photons. (This doesn't take into account that photons additionally take [https://news.stanford.edu/pr/97/971219neutrino.html a hundred thousand years to reach the Sun's surface] from the core where they're generated.) However, as the neutrinos have been travelling at more than 99.999% of the speed of light, they will have aged by less than two seconds,[https://www.omnicalculator.com/physics/time-dilation] and so are technically even fresher.<br /> <br /> your mom sucked my fat cock<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[A picture of a box with writing on one side, saying as follows:]<br /> <br /> :30,000 neutrinos<br /> :&lt;small&gt;Freshly produced&lt;/small&gt;<br /> :Plus 4 zeptograms of dark matter<br /> <br /> :[Caption below the panel]: <br /> :Cosmologists are easy to shop for because you can just get them a box.<br /> <br /> {{comic discussion}}<br /> [[Category:Astronomy]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2643:_Cosmologist_Gift&diff=288542 2022-07-10T00:12:50Z

<p>172.70.211.36: /* Explanation */ liters are easier units</p> <hr /> <div>{{comic<br /> | number = 2643<br /> | date = July 8, 2022<br /> | title = Cosmologist Gift<br /> | image = cosmologist_gift.png<br /> | titletext = These neutrinos were freshly produced by a local source just 8 minutes ago<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a MUON ON SALE, PACKAGED IN A BOX THAT A CAT MIGHT OR MIGHT NOT HAVE DIED IN- Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> This comic shows a box labeled to indicate that it contains 30,000 fresh {{w|neutrino}}s and four zeptograms of {{w|dark matter}}. The box is intended as an inexpensive gift for a {{w|cosmologist}}. The gift giver didn't put those things in the box—both are simply passing through it, so the &quot;gift&quot; consists of exactly what was in the empty space it occupies. While the caption suggests this would be a good gift for a cosmologist, what they or anyone else would do with such a box is uncertain.<br /> <br /> There are about a billion neutrinos per cubic meter throughout space, produced during the {{w|Big Bang}}.[https://physics.mit.edu/news/journal/physicsatmit_14_conrad/] However, the flux of &quot;freshly produced&quot; {{w|solar neutrino}}s at Earth is around 7&amp;times;10&lt;sup&gt;10&lt;/sup&gt;/cm&lt;sup&gt;2&lt;/sup&gt;/s, yielding about 2.3 million per cubic meter, implying the box is around 13 liters, about 80% the size of a typical {{w|breadbox}}.<br /> <br /> Four zeptograms is a minuscule mass, equal to four sextillionths of a gram, or the mass of about 200 carbon-12 atoms. There is an estimated 0.011 to 0.016 {{w|solar mass}}es of dark matter per cubic {{w|parsec}} locally to the solar system,[https://iopscience.iop.org/article/10.1088/1361-6633/ac24e7/meta] about 900 zeptograms per cubic meter, suggesting the box is closer to 4 liters. This discrepancy could imply Randall agrees with cosmologists who believe dark matter is partially composed of {{w|primordial black hole}}s,[https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.121301][https://www.sciencedirect.com/science/article/abs/pii/S2212686418301250?via%3Dihub][https://news.yale.edu/2021/12/16/black-holes-and-dark-matter-are-they-one-and-same][https://iopscience.iop.org/article/10.3847/2041-8205/823/2/L25][https://iopscience.iop.org/article/10.1088/1475-7516/2010/04/023] instead of being entirely composed of pervasive subatomic particles. A billion neutrinos have a mass of only about 2×10&lt;sup&gt;-12&lt;/sup&gt; zeptograms, at about 0.1 {{w|electron volt}}s each.<br /> <br /> The &quot;local source&quot; mentioned in the title text is a pun on the commercial value of fresh, locally produced items, but here it is the Sun. It takes neutrinos not much more than 8 minutes to reach Earth once they're emitted, roughly the same time as photons. (This doesn't take into account that photons additionally take [https://news.stanford.edu/pr/97/971219neutrino.html a hundred thousand years to reach the Sun's surface] from the core where they're generated.) However, as the neutrinos have been travelling at more than 99.999% of the speed of light, they will have aged by less than two seconds,[https://www.omnicalculator.com/physics/time-dilation] and so are technically even fresher.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[A picture of a box with writing on one side, saying as follows:]<br /> <br /> :30,000 neutrinos<br /> :&lt;small&gt;Freshly produced&lt;/small&gt;<br /> :Plus 4 zeptograms of dark matter<br /> <br /> :[Caption below the panel]: <br /> :Cosmologists are easy to shop for because you can just get them a box.<br /> <br /> {{comic discussion}}<br /> [[Category:Astronomy]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=Talk:2643:_Cosmologist_Gift&diff=288521 2022-07-09T09:44:20Z

<p>172.70.211.36: Correct proportion</p> <hr /> <div>&lt;!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--&gt;<br /> - The explanation mentions “Eight zeptograms” although Randall’s box says “4 zeptograms of dark matter.”<br /> <br /> - The 4,800 daltons in the explanation is roughly the size of a small protein; for example, insulin is about 5,800 daltons.<br /> <br /> - Randall’s box says it contains 4 zeptograms of dark matter. Could someone explain this? My incomplete (biologist’s) understanding of dark matter is that astrophysicists do not yet know what it is. So how could Randall claim the box contains 4 zeptograms of it?<br /> <br /> Thanks!<br /> <br /> :Fixed; thank you. [[Special:Contributions/172.70.210.125|172.70.210.125]] 01:18, 9 July 2022 (UTC)<br /> <br /> [https://arxiv.org/abs/2204.09143 Here's] a more recent PBH DM source than those already cited which could comport with Randall's 0.4% DM particles implication, but doesn't do so explicitly. [[Special:Contributions/172.70.206.213|172.70.206.213]] 02:35, 9 July 2022 (UTC)<br /> :With the math corrected per 162.158.134.89 below, the figure is 34% ubiquitous particles. [[Special:Contributions/172.70.211.36|172.70.211.36]] 09:44, 9 July 2022 (UTC)<br /> <br /> And this comic was the perfect birthday gift for me. [[Special:Contributions/108.162.245.203|108.162.245.203]] 02:42, 9 July 2022 (UTC)<br /> <br /> * How was the 23,000 neutrinos/m³ figure obtained? A flux of 7e10/(s·cm²), or 7e14/(s·m²), at a speed of close to 3e8 m/s, gives 2.3e6/m³. That would correspond to a box size of about 0.013 m³, or a bit larger than a typical shoe box. [[Special:Contributions/162.158.134.89|162.158.134.89]] 07:19, 9 July 2022 (UTC)<br /> ::Corrected. [[Special:Contributions/172.70.211.52|172.70.211.52]] 09:40, 9 July 2022 (UTC)</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2643:_Cosmologist_Gift&diff=288502 2022-07-09T02:02:43Z

<p>172.70.211.36: /* Explanation */ mass of a billion neutrinos, wikilink to specific kind of black holes</p> <hr /> <div>{{comic<br /> | number = 2643<br /> | date = July 8, 2022<br /> | title = Cosmologist Gift<br /> | image = cosmologist_gift.png<br /> | titletext = These neutrinos were freshly produced by a local source just 8 minutes ago<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a MUON ON SALE- Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> This comic shows a box labeled to indicate that it contains 30,000 fresh {{w|neutrino}}s and four zeptograms of {{w|dark matter}}. The box is intended as an inexpensive gift for a {{w|cosmologist}}. The gift giver didn't put those things in the box; both are simply passing through it. While the caption states that this would be a good gift for a cosmologist, what they or anyone else would do with such a box is uncertain.<br /> <br /> There are about a billion neutrinos per cubic meter throughout space, produced during the {{w|Big Bang}}.[https://physics.mit.edu/news/journal/physicsatmit_14_conrad/] However, the flux of &quot;freshly produced&quot; {{w|solar neutrino}}s at Earth is around 7&amp;times;10&lt;sup&gt;10&lt;/sup&gt;/cm&lt;sup&gt;2&lt;/sup&gt;/s, yielding about 23,000 per cubic meter. <br /> <br /> Four zeptograms is a minuscule mass, equal to four sextillionths of a gram, or the mass of about 200 carbon-12 atoms. There is an estimated 0.011 to 0.016 {{w|solar mass}}es of dark matter per cubic {{w|parsec}} locally to the solar system,[https://iopscience.iop.org/article/10.1088/1361-6633/ac24e7/meta] or about 900 zeptograms per cubic meter. This discrepancy with the number of solar neutrinos in the box suggests Randall might agree with the cosmologists who believe that dark matter is at least partially composed of {{w|primordial black holes}},[https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.121301][https://www.sciencedirect.com/science/article/abs/pii/S2212686418301250?via%3Dihub][https://news.yale.edu/2021/12/16/black-holes-and-dark-matter-are-they-one-and-same][https://iopscience.iop.org/article/10.3847/2041-8205/823/2/L25][https://iopscience.iop.org/article/10.1088/1475-7516/2010/04/023] instead of being entirely composed of pervasive subatomic particles. A billion neutrinos have a mass of only about 2×10&lt;sup&gt;-12&lt;/sup&gt; zeptograms, at about 0.1 {{w|electron volt}}s each.<br /> <br /> The &quot;local source&quot; mentioned in the title text is the Sun; it takes light and neutrinos 8 minutes to reach Earth once they're emitted.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[A picture of a box with writing on one side, saying as follows:]<br /> <br /> :30,000 neutrinos<br /> :&lt;small&gt;Freshly produced&lt;/small&gt;<br /> :Plus 4 zeptograms of dark matter<br /> <br /> :[Caption below the panel]: <br /> :Cosmologists are easy to shop for because you can just get them a box.<br /> <br /> {{comic discussion}}<br /> [[Category:Astronomy]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2638:_Extended_NFPA_Hazard_Diamond&diff=288457 2022-07-08T21:00:34Z

<p>172.70.211.36: Total speculation</p> <hr /> <div>{{comic<br /> | number = 2638<br /> | date = June 27, 2022<br /> | title = Extended NFPA Hazard Diamond<br /> | image = extended_nfpa_hazard_diamond.png<br /> | titletext = With most labs, the hushed horror stories are about something like dimethylmercury or prions, but occasionally you'll get a weird lab where it's about the soda machine or the drop ceiling.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a SUBSTANCE WORTH $500 IN STREET VALUE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> This comic depicts an extension of the National Fire Protection Association's {{w|NFPA 704|NFPA 704 Standard System for the Identification of the Hazards of Materials for Emergency Response}} &quot;fire diamond&quot; emblematic insignia used to warn about the properties of hazardous substances inside a building, vehicle, room, cabinet, or container that are important during an emergency or accident, such as a fire, earthquake, spill or leak, bringing the diamond from 2x2 squares to 3x3 by adding five variously useful and humorous squares along the bottom edges.<br /> <br /> The numbers in a normal NFPA 704 diamond do not specify values of substances' properties, but rather broad categories designating characteristics of the substances of greatest interest to {{w|first responders}} and hazardous materials cleanup crews. Randall's expanded diamond breaks with this convention, with several squares (Lilac, Orange, and Black) denoting absolute values, and one square (Green) denoting an economic value. This could very easily lead to documentation update headaches, especially since the Green square is mostly determined by supply and demand, and the Lilac square is linked to political outcomes.<br /> <br /> {| class=&quot;wikitable&quot;<br /> |+ Squares and explanations<br /> |-<br /> ! Square !! Color !! Comic text !! Explanation<br /> |-<br /> !colspan=5| Real NFPA 704 diamond [http://www.ilpi.com/msds/ref/nfpa.html square and number meanings]<br /> |-<br /> | Top || Red || Flammability (0) || Denotes flammability. 0 indicates &quot;materials that will not burn.&quot;<br /> |-<br /> | Top Left || Blue || Health Hazard (4) || Denotes the danger that the substance(s) pose to living beings in ways other than flammability and reactivity. 4 indicates that &quot;Very short exposure could cause death or serious residual injury even though prompt medical attention was given.&quot;<br /> |-<br /> | Top Right || Yellow || Instability (2) || Denotes how stable the substance(s) are when exposed to water, heat, shock, air, or other substances. 2 indicates that &quot;Normally unstable and will readily undergo violent decomposition but does not detonate. Also: may react violently with water or may form potentially explosive mixtures with water.&quot;<br /> |-<br /> | Center || White || (Special Hazard) || The standard's &quot;Special Notice&quot; field may contain a symbol denoting additional information about the substance(s), e.g., '''OX''' for {{w|oxidizer}}s, '''SA''' for simple {{w|asphyxiant}} gases such as nitrogen and helium, and &lt;s&gt;'''W'''&lt;/s&gt; for substances which react dangerously with water.<br /> |-<br /> !colspan=5| After this point, all squares are made up by Randall.<br /> |-<br /> | Center Left || Green || Number of digits in the street value ($/gram) (2) || Describes the order of magnitude of the price (in USD) of one gram of the substance when sold illegally and informally. This is done on a logarithmic scale, with a '1' selling for $9/gram or less, a '2' selling for $10-$99/gram, and so on. As such this is the first of several squares where the number may presumably go to 5 or above (which is not allowed on the original Blue/Red/Yellow squares, as they do not denote strict numerical values). That said it's not immediately clear how substances which command &lt;$1/gram would be handled.<br /> <br /> Randall's example substance apparently sells for tens of dollars per gram (which would be similar to most common illicit drugs).<br /> |-<br /> | Center Right || Dark Purple || How much of a hassle it is to dispose of (4) || While many things can be thrown in the trash with no additional procedures, substances that merit an NFPA 704 square often require additional procedures to avoid significant danger, damage to the environment, or hefty dumping fines. Biohazards that may carry diseases are often disposed of in special containers, and nuclear materials are notoriously difficult to safely dispose of. This square would be at least theoretically useful, though not as much as the actual disposal guidelines.<br /> <br /> If the numbering here follows the scheme of the real categories, Randall's example substance is about as hard to dispose of as it gets. This matches the substance's rating of 4 for Blue and 2 for Yellow. Presumably it requires highly specialized handling or processing, and may also very bulky or awkward to store.<br /> |-<br /> | Bottom Left || Lilac || Number of federal agencies who want to know if you have any (3) || In many countries, including Randall's home country, the USA, the government has agencies dedicated to controlling or limiting the use of regulated substances, due to their use as drugs, weapons, harm to the environment, etc. While any given substance might be of interest to one agency, something that is both an environmental hazard and a chemical weapon component could interest, for example, the {{w|EPA}}, {{w|Chemical Safety Board}} and the FBI Counter-terrorism Division.<br /> |-<br /> | Bottom Right || Orange || How many times you have to scrub your hands after touching it before they stop smelling weird (1) || While the real NFPA 704 chart describes properties ranging from unsafe to potentially deadly, this square describes a minor but very real inconvenience. Some things are harder to wash off your hands than others, and, given that most people don't often work with dangerous substances {{Citation Needed}}, this would be a more common, but less relevant, concern for many people.<br /> <br /> In this case, the substance, or its residue, seems to be fairly easy to wash off. This is seemingly incongruous with its ratings in the Blue and Black squares (see below), though it's possible that this substance simply doesn't have a strong odor.<br /> |-<br /> | Bottom || Black || Number of times it's caused one of those terrifying lab accidents that chemists tell scary stories about late at night (2) || This square might show how concerned and careful someone should be in handling the substance in question, especially if the number is more than one. However, it would be dependent not just on how inherently dangerous the substance is, but also on how commonly it occurs in labs. It's also vague as to what kind of accidents it has been involved in and what precautions therefore need to be taken. It could, for example, have caused some terrifying reaction, destroying things around it, or it could be very large and unwieldy and liable to crush people if handled improperly.<br /> <br /> In this case, it seems the substance has caused two such accidents, presumably on account of its high health risk of 4 in the Blue square, and may also be linked to its hazardous disposal score of 4 in the Purple square.<br /> |}<br /> <br /> The title text (which references &quot;scary stories&quot; of the Black square) refers to {{w|dimethylmercury}} and {{w|prions}}. Dimethylmercury, C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;Hg, is an organic form of mercury with an NFPA score of 4-4-3 (contact can be fatal, will burn below 73° F (22 °C), will combust if put under pressure). In 1997, an American chemist, {{w|Karen Wetterhahn}}, died 298 days after a few drops of C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;Hg on her latex gloves were absorbed into her hand through the gloves, causing fatal mercury poisoning. Despite her having followed all safety protocols of the time, it was not then understood that the chemical was so toxic, nor that latex was so permeable to it. Prions are misfolded proteins that are responsible for a number of neurodegenerative diseases, including {{w|mad cow disease}} and {{w|chronic wasting disease}} in non-human animals and {{w|Creutzfeldt-Jakob disease}} in humans. These would indeed be the kind of substances that would scare those working with them in their labs; if an accident occurred, the results could be calamitous. See for example the case of [https://arstechnica.com/science/2021/07/second-lab-worker-with-deadly-prion-disease-prompts-research-pause-in-france/ Émilie Jaumain], a lab technician who died after accidentally coming into contact with prions in mouse tissue.<br /> <br /> But a few labs have apparently had accidents involving a soda machine or {{w|dropped ceiling}}. The latter may be a reference to {{w|1978 smallpox outbreak in the United Kingdom|the death of Janet Parker}}: One inquiry found that she was infected with {{w|smallpox}} when a sample traveled upward from a lab on the floor below hers; however, other investigations have challenged that finding. There are occasional instances of vending machines causing injury or death, usually caused by people trying to shake or tilt the machines to get product out and having the machine tip and fall on them. On average, [https://www.cpsc.gov/Newsroom/News-Releases/1996/CPSC-Soda-Vending-Machine-Industry-Labeling-Campaign-Warns-Of-Deaths-And-Injuries a couple of Americans per year] are killed in this way. Reagents obtained in this way tend to have more impurities than those usually used in labs, but are relatively safe to shake.<br /> <br /> The only easily identifiable substance which could likely meet the specific insignia numbers shown in the comic is {{w|thionyl chloride}} (SOCl&lt;sub&gt;2&lt;/sub&gt;), a chlorinating reagent and solvent regulated as a chemical weapons precursor and sometimes used in the production of methamphetamine, which would also be represented with the '''&lt;s&gt;W&lt;/s&gt;''' symbol inside the white square, indicating reactivity with water. <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> :Know your extended NFPA hazard diamond:<br /> <br /> :[The diamond is divided into 3x3 squares.]<br /> :Flammability: 0 (top, red)<br /> :Health hazard: 4 (top-left, blue)<br /> :Instability/reactivity: 2 (top-right, yellow)<br /> :Number of digits in the street value ($/gram): 2 (left, green)<br /> :(Special hazard) (center, white)<br /> :How much of a hassle it is to dispose of: 4 (right, purple)<br /> :Number of federal agencies who want to know if you have any: 3 (bottom-left, pink)<br /> :How many times you have to scrub your hands after touching it before they stop smelling weird: 1 (bottom-right, orange)<br /> :Number of times it's caused one of those terrifying lab accidents that chemists tell scary stories about late at night: 2 (bottom, black)<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Science]]<br /> [[Category:Chemistry]]<br /> [[Category:Comics with color]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=Talk:2641:_Mouse_Turbines&diff=288264 2022-07-05T03:21:27Z

<p>172.70.211.36: Opinion</p> <hr /> <div>&lt;!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--&gt;<br /> Is anybody going to try to calculate the amount of power such a turbine could collect? -- [[User:Dtgriscom|Dtgriscom]] ([[User talk:Dtgriscom|talk]]) 19:24, 4 July 2022 (UTC)<br /> :Good idea; what should we use for an estimate of the geometry for https://www.omnicalculator.com/ecology/wind-turbine ? The final panel makes it look like the blade diameter is about twice the size of a fist. [https://www.sciencedirect.com/science/article/pii/S2215098616300830] says &quot;exhaled air velocity varies from 2.2 m/s to 9.9 m/s (5.66 ± 1.57 m/s, mean ± SD) and exhalation time varies from 2.10 s to 8.21 s (4.42 ± 1.73s, mean ± SD).&quot;<br /> :I guessed 10 cm radius and used that mean breath speed. I should have used the top 9.9 m/s though, shouldn't I? [[Special:Contributions/172.70.214.185|172.70.214.185]] 20:56, 4 July 2022 (UTC)<br /> :After a closer look at that article, the mean is more appropriate. [[Special:Contributions/172.70.206.95|172.70.206.95]] 21:19, 4 July 2022 (UTC)<br /> <br /> Although these miniscule wind turbines don't generate much power, mice probably don't need much. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 21:17, 4 July 2022 (UTC)<br /> :That's certainly a fair point. How much power would a mouse-sized fridge need? [[Special:Contributions/172.70.206.95|172.70.206.95]] 21:23, 4 July 2022 (UTC)<br /> <br /> Someone please check my mouse energy needs math and assumptions. I made a couple misplaced decimal mistakes getting to where it is now, and I'm going to have another beer. [[Special:Contributions/172.70.211.52|172.70.211.52]] 22:17, 4 July 2022 (UTC)<br /> <br /> I'm confused by the statement that smaller turbines are less &quot;efficient&quot;. There's nothing about efficiency at that link. [[Special:Contributions/172.70.114.43|172.70.114.43]] 22:33, 4 July 2022 (UTC)<br /> :The graph shows the ratio between size and output has risen from about half to 85%. What is a better term for this? I'm pretty sure one of the multiple definitions of efficiency is technically correct, but it can never hurt explaining better. [[Special:Contributions/172.69.33.113|172.69.33.113]] 22:42, 4 July 2022 (UTC)<br /> :Changed to &quot;relative power output&quot; but I'm not sure that captures the idea very well either. [[Special:Contributions/172.69.33.113|172.69.33.113]] 22:44, 4 July 2022 (UTC)<br /> <br /> Well wind turbines may not scale down ideally but still better than nuclear power plants. I suspect those have fixed minimal size and it's pretty big. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 23:32, 4 July 2022 (UTC)<br /> <br /> :Apparently nuclear power can be [https://technology.nasa.gov/patent/LAR-TOPS-294 &quot;as small as a button cell&quot;] but mice are vulnerable to radioactive hazards, and haven't solved the waste disposal problem. [[Special:Contributions/172.70.214.185|172.70.214.185]] 23:45, 4 July 2022 (UTC)<br /> <br /> Isn't the power output of a solar panel directly dependent on its size (and wether it's covered with snow, angle to the sun, clouds? And prolly something I'll think of as soon as I hit save).[[Special:Contributions/172.70.131.106|172.70.131.106]] 23:55, 4 July 2022 (UTC)<br /> :Yes, but the power per size doesn't increase with size like wind turbines do. [[Special:Contributions/172.69.33.63|172.69.33.63]] 00:01, 5 July 2022 (UTC)<br /> <br /> What is the smallest Tesla Powerwall available for purchase? [[Special:Contributions/172.70.206.163|172.70.206.163]] 02:00, 5 July 2022 (UTC)<br /> :You probably want an {{w|18650}} or similar cell, which are [https://www.youtube.com/watch?v=PsJMj7FtroY frequently discarded on the street] and thus easily obtainable by mice. [[Special:Contributions/172.69.33.171|172.69.33.171]] 03:02, 5 July 2022 (UTC)<br /> <br /> Why doesn't pico hydro have the same problems scaling down as wind? They're both fluid turbines. [[Special:Contributions/172.70.214.185|172.70.214.185]] 02:24, 5 July 2022 (UTC)<br /> :For the same reasons that small fans have several vanes, but large wind turbines have only three. I remember reading something about the physics (it's a laminar versus turbulent thing) but I can't remember the details now. I'll update here if I can find it. [[Special:Contributions/172.70.210.125|172.70.210.125]] 03:08, 5 July 2022 (UTC)<br /> :[https://www.sciencefocus.com/science/why-do-wind-turbines-have-three-blades/ Here's part of it,] but doesn't really get to the heart of the matter. [[Special:Contributions/172.70.210.125|172.70.210.125]] 03:10, 5 July 2022 (UTC)<br /> :I think it has more to do with the relative magnitude of drag in gases instead of liquids. I don't have a good source though. [[Special:Contributions/172.70.211.36|172.70.211.36]] 03:21, 5 July 2022 (UTC)</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2641:_Mouse_Turbines&diff=288252 2022-07-05T01:16:42Z

<p>172.70.211.36: /* Explanation */ preposition</p> <hr /> <div>{{comic<br /> | number = 2641<br /> | date = July 4, 2022<br /> | title = Mouse Turbines<br /> | image = mouse_turbines.png<br /> | titletext = It's sad seeing those videos of turbine blade being torn apart in high winds, but it's the only way they can disperse their seeds.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a RENEWABLE ENERGY RODENT - Elaborate on the title text. Do NOT delete this tag too soon.}}<br /> <br /> [[Beret Guy]] and [[Megan]] are walking during the summer, where Beret Guy expresses his appreciation for typical features of a summer day. He also mentions &quot;wind turbines&quot; put up by field mice, which Megan initially assumes to be referring to dandelions (similar to the wordplay that Beret Guy utilized in [[1322: Winter]].) However, Beret Guy turns out to be speaking literally, as he picks up what is in fact a tiny {{w|wind turbine}}, asks Megan to [https://www.dandelionpress.com/dandelion-blog/2015/4/6/how-to-wish-on-a-dandelion make a wish,] and blows into it. This causes the blades of the turbine to spin very rapidly, generating a lot of power for the structure it is connected to, thus causing a field mouse to cheer in excitement.<br /> <br /> Sadly, the power output per size of wind turbines increases with their size,[https://www.energy.gov/eere/articles/wind-turbines-bigger-better] a limitation not shared by other forms of renewable energy such as {{w|solar panel}}s and {{w|pico hydro}}. According to [https://www.omnicalculator.com/ecology/wind-turbine this calculator], a 10 centimeter radius wind turbine powered by a 5.7 meter/second breath[https://www.sciencedirect.com/science/article/pii/S2215098616300830] would produce one watt at just 26% efficiency.<br /> <br /> Further frustrating mouse use of wind power, {{w|Wind gradient|windspeed increases logarithmically with height}} above ground. Windspeed is reported as its value 10 meters above ground, where it is 1.5 times faster than at ground level.[https://www.nooutage.com/wind.htm] In the U.S., where Randall lives, average year-round windspeed is about 15 km/h,[https://sciencing.com/average-daily-wind-speed-24011.html] or about 2.8 m/s at ground level, yielding only 0.11 watts from such turbines. However, a typical mouse weighs 25 grams,[https://web.jhu.edu/animalcare/procedures/mouse.html] compared to about 81 kilograms for humans in the U.S.,[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3408371/] so presumably mouse electricity needs would be about 0.03% of people's. The average U.S. residential customer uses 1,242 watts of electricity,[https://www.electricchoice.com/blog/electricity-on-average-do-homes/] 0.03% of which is 0.37 watts. Therefore, three such turbines could be able to serve about 89% of a mouse's needs. While this figure does not account for necessary {{w|home energy storage}} efficiency overhead, mice usually live much less extravagantly than typical Americans,{{citation needed}} so three turbines per mouse should be sufficient.<br /> <br /> The title text adds to the similarities between wind turbines and dandelions by claiming that turbines reproduce by dispersing their blades, in the manner of dandelion {{w|seed dispersal}}. Randall's suggestion of turbine seeds conflicts with Beret Guy's assertion that the turbines were built by field mice.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Megan and Beret Guy are walking on grass.]<br /> :Beret Guy: Ahh, summer!<br /> :Beret Guy: The clouds are big, the bugs are zooming,<br /> <br /> :[Beret Guy stops walking. There are three small trefoil structures and a tiny building on the grass in front of him.]<br /> :Beret Guy: and the field mice have put up their little wind turbines.<br /> <br /> :[Beret Guy picks up one of the turbines. Under the turbine there is a wire attached to the ground.]<br /> :Megan (off-panel): You mean dandelions?<br /> :Beret Guy: No.<br /> <br /> :[Beret Guy holds the turbine in front of him.]<br /> :Beret Guy: Make a wish!<br /> <br /> :[Beret Guy blows into the turbine blades and makes them spin. The wire transfers electricity towards the ground.]<br /> :''Puff''<br /> :⚡ ⚡ ⚡ ⚡<br /> :Voice at ground level: Yaaay!<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Comics featuring Megan]]<br /> [[Category:Comics featuring Beret Guy]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=Talk:2636:_What_If%3F_2_Countdown&diff=288251 2022-07-05T01:10:17Z

<p>172.70.211.36: Reply</p> <hr /> <div>&lt;!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--&gt;<br /> I've started the table to explain all the calendar entries. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 00:19, 23 June 2022 (UTC)<br /> <br /> Is the dog minutes calculation backwards? 777,777 dog minutes should be 777,777 x 7 human minutes, which is over 10 years. Randall seems to be dividing instead of multiplying. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 00:36, 23 June 2022 (UTC)<br /> : No - 1 human year = 7 dog years; 1 dog year = 1/7 human year; 1 dog minute = 1/7 human minute; 777,777 dog minutes = 111,111 human minutes = 77 days, 3 hours, 51 minutes. [[Special:Contributions/172.70.90.173|172.70.90.173]] 11:32, 23 June 2022 (UTC)<br /> <br /> First entry is probably mistake by Randall, e^pi would give value of 84.5 [[Special:Contributions/162.158.203.38|162.158.203.38]] 11:57, 23 June 2022 (UTC)<br /> : That would be too high, though. 82.xxx days (from midnight at the start of launch day) would fall within the 83rd day before it (Jun 22). 84.5 would fall within the 85th (Jun 20). [[Special:Contributions/172.70.91.58|172.70.91.58]] 12:15, 23 June 2022 (UTC)<br /> <br /> Not sure if this is even worth mentioning, but he forgot the box around the date number in the top corner for August 29th. [[Special:Contributions/172.70.126.151|172.70.126.151]] 12:49, 23 June 2022 (UTC)<br /> <br /> Fyi, used wolfram alpha for most of the calculations. Seems to be able to handle anything I throw at it (nanocenturies, megaseconds, fortnights etc) [[User:Aditya95sriram|Aditya95sriram]] ([[User talk:Aditya95sriram|talk]]) 13:02, 23 June 2022 (UTC)aditya95sriram<br /> <br /> Some of the calculations done forward (assuming what Randall means as a Generation, for example) might be best done as &quot;to get this many days, what does Randall think ilhe is starting from. And see if 365, 365.25 or even 365.24 days per year works best, where relevent. Although I think in many cases you'll find the fractional differences negligable, when done right. (I'm also a bit surprised by the off-by-one errors in days-to-go and derived value, but I suspect that this is because of [[2585: Rounding|assymetric rounding effects]] that would be revealed by running the assumption backwards and seeing how different (or otherwise) the decimals actually are.) [[Special:Contributions/172.70.85.211|172.70.85.211]] 13:32, 23 June 2022 (UTC)<br /> : I would suggest using 365.2425 days per year, as that's consistent with current leap year conventions. [[User:Dansiman|Dansiman]] ([[User talk:Dansiman|talk]]) 21:49, 23 June 2022 (UTC)<br /> :: Did not see your comment, but already done trivial replacement. No recalculation that goes more complicated than magnitude, though.<br /> ::(For the mathematically curious, in the Gregorian calendar it's normally 365 days, but a leap day every four years (+0.25 =&gt; 365.25), except no leap day every century (-0.01 =&gt; 365.24), except there is every fourth century (+0.0025 =&gt; 365.2425). Which is very very close to the more astronomically-precise figure of 365.2422, at least at this point in our planet's history and definitely over the timescale of the Gregorian calendar itself. ''edit-to-add-convoluted-musings'': A successor system ''might'' need to de-reinstate three of the Four-Millenial leap-days in every 10,000 year period, or perhaps by re-removing four of its various leap-days then re-reinstating one of ''those'' back again, but by the time it's relevent I doubt that 365.2422 is going to be as valid for whatever reason... Hey, by then, maybe we could just deliberately adjust the Earth in or out a bit to make it a better fraction/not a fraction at all! )<br /> ::On the other hand, the old adage is &quot;no use being precise over imprecise details&quot;. One can perhaps apply it to nominal decades (the true average decade; though a given decade might be 10*365 days plus either ''two'' or ''three'' leap-days, for 3652.5±0.5 days in that instance... not equally likely each way, though) but the Generations calculation already ''assumes'' 27 years per generation (not even 27.5, exactly half way between 22 and 33, which already seems a dubious backformation to suit other purposes) and gets a good-enough ''approximate'' number. Using a factor precise to around 1 in 146000 alongside one that's unlikely to be even as accurate as 1 in 54 is a bit rich and overly anal (rather than analytic) in the long-run.<br /> ::But this is explainxkcd, so I'm not saying it's misplaced, just that those who would be pedantic about everything (myself included) might find themselves even more out-pedanted in very reasonable circumstances... ;) [[Special:Contributions/172.70.162.77|172.70.162.77]] 22:47, 23 June 2022 (UTC)<br /> <br /> Not sure about most numbers but at least the order of magnitude seemed plausible. I can't quite find a proper way to read August 28th. π^π^π is roughly 80662.666 - if you read πcoseconds as &quot;picoseconds&quot;, that's way less than a second. I have no idea what π * coseconds are supposed to be. π * c * o * seconds doesn't look much better - there are values associated with &quot;c&quot; (speed of light, for example) but I have no idea what &quot;o&quot; could be and certainly nothing that would make this a unit of time. Sixteen days would be 1,353,600,000,000,000,000 ps (picoseconds). π^π^π^π is three orders of magnitude too small, π^π^π^π^π is many orders of magnitude too big a number. Am I missing something (really obvious, maybe?) here? [[User:627235|627235]] ([[User talk:627235|talk]]) 14:52, 23 June 2022 (UTC)<br /> : Exponent towers are by convention evaluated top-down, so pi^pi^pi should be read as pi^(pi^pi), which is ~1.34e18, which in picoseconds is ~15.51 days. [[Special:Contributions/172.70.114.71|172.70.114.71]] 15:21, 23 June 2022 (UTC)<br /> <br /> 10,000 minutes in Heaven is making out for a week. I was able to find a record for the longest kiss (58 hours, 35 minutes), but not the longest make-out session. I think Randall may be indulging in some nerdy wishfull thinking. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 15:27, 23 June 2022 (UTC)<br /> <br /> When the beer song reached F(0) how would you 'take one down' from -1 bottles of beer? Would they be imaginary bottles of beer? (Joking) At F(n-1) would there be a matter/antimatter annihilation, where Randal could do a riff of What-If #1 and describe the play by play of the bartender turning into exotic forms of matter? [[Special:Contributions/172.69.68.88|172.69.68.88]] 15:58, 23 June 2022 (UTC)<br /> :(Not ✓-1, it's just straight repeated subtraction, not a power function...) After so much beer, you probably think it a good idea (even necessary) to fill cans up and start to put them back up on the wall... Not sure you could sustain it, to the point of F(-99), but I think someone'd be more than ready to start the process when F(-1) is invoked, for any group of just a few likely individuals.. [[Special:Contributions/172.70.91.58|172.70.91.58]] 16:23, 23 June 2022 (UTC)<br /> :This begs the question of what beer bottles are doing on a wall, rather than a shelf. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 16:26, 23 June 2022 (UTC)<br /> : Randall already considered what happens at F(0), refer to the title text. [[User:Paddles|Paddles]] ([[User talk:Paddles|talk]]) 08:16, 24 June 2022 (UTC)<br /> : If you wanted to take down an imaginary bottle of beer, you'd have to take it from another wall that runs orthogonal to the original wall. [[Special:Contributions/172.70.85.211|172.70.85.211]] 08:50, 24 June 2022 (UTC)<br /> <br /> We've finally filled in all the units columns in the table. Hopefully someone can automate turning that into a transcript. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 16:51, 23 June 2022 (UTC)<br /> <br /> Funfact: This comic mentions Cyndi Lauper by name, and it was published on her birthday… [[Special:Contributions/162.158.38.27|162.158.38.27]] 20:51, 23 June 2022 (UTC)<br /> :Sweet! I'm a big fan of playing ''Time after Time'' on repeat to get into a flow state, so I loved that one. [[Special:Contributions/162.158.166.183|162.158.166.183]] 20:43, 24 June 2022 (UTC)<br /> <br /> Looks like someone's math is wrong on the explanation for July 18. I calculated using 4681 and 4763 years and they came out to 51.29 days and 52.19 days, respectively. So then I worked backwards and determined that Randall would actually have to be using a number closer to 5200 years to arrive at the correct result of 57 days. [[User:Dansiman|Dansiman]] ([[User talk:Dansiman|talk]]) 21:49, 23 June 2022 (UTC)<br /> <br /> Randall seems to be wrong about &quot;It's a Small World&quot;. The song is about 2 minutes long, so at 1/10,000 speed it's 20,000 minutes = 14 days. He seems to be using a length a little over 3 minutes. I found a YouTube video of the ride that's 3:45, but the song ends at 2:15 and the rest is silent. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 22:16, 23 June 2022 (UTC)<br /> :[https://www.youtube.com/watch?v=PxRW-duSCLA This video of it] on YouTube lasts 3:02. It was uploaded by Universal Music Group (allied with Disney), making it some kind of 'official' version, and its length fits Randall's calculation. (Also, thanks for making the table!) [[User:DKMell|DKMell]] ([[User talk:DKMell|talk]]) 22:38, 23 June 2022 (UTC)<br /> ::That could be it. It has a long instrumental coda after the singing is done. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 14:07, 24 June 2022 (UTC)<br /> <br /> Could &quot;eπ Ionian months&quot; also be a very subtle reference to the {{w|Euler identity}} given the first two characters of Ionian? Or am I reading/visualising a bit too much into it? [[User:Paddles|Paddles]] ([[User talk:Paddles|talk]]) 08:16, 24 June 2022 (UTC)<br /> <br /> Aug 26 needs editing, but I just reset my password and can't fix it. At 4 breaths per minute, 100,000 breaths is 17.36 days. To get 17 days exactly, Randall would need to assume about 4.085 breaths per minute. [[User:Wjw|Wjw]] 08:24, 24 June 2022 (UTC)<br /> :Most of the calculations are very approximate. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 14:07, 24 June 2022 (UTC)<br /> ::Many of them were given to subsecond digits of precision, too, so I rounded everything off to two significant digits of days unless there was some compelling reason to have 0, 1, or 3. Don't @ me, because I filled up and homogenized all that column, finally (except for 100,000 breaths, which are slow enough to be what I'm guessing is probably Randall's error.) If someone wants to get a better value for the total duration of ''Star Trek'' than the January, 2021 reference I found by counting all the released episodes since up to the date of the cartoon, please do. [[Special:Contributions/162.158.166.183|162.158.166.183]] 20:26, 24 June 2022 (UTC)<br /> :::For ''Star Trek'' total run time, it might be best to count all episodes scheduled for release up until August 14, the date of that specification. [[Special:Contributions/172.70.210.233|172.70.210.233]] 21:02, 24 June 2022 (UTC)<br /> <br /> There's a closing /div HTML tag on the front page after the transcript (but not on this page). [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 17:21, 24 June 2022 (UTC)<br /> <br /> Thoughts on including a &quot;% of error&quot; column in the table?[[Special:Contributions/172.70.130.121|172.70.130.121]] 15:54, 27 June 2022 (UTC)<br /> :An additional column would make it look worse on mobile portrait, and a residual error wouldn't really explain anything that readers couldn't get a gist of by eyeballing. [[Special:Contributions/172.70.210.233|172.70.210.233]] 01:31, 3 July 2022 (UTC)<br /> :Most of these don't really have a margin of error, they're all based on specific numbers, beyond that most of them can go to a ridiculous number of decimal places (mostly due to the infinite decimal places of pi, e and phi). Rounding to 2 decimal places is sufficient and doesn't count as a &quot;margin of error&quot;. [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 23:54, 3 July 2022 (UTC)<br /> <br /> Several entries were rather unspecific, particularly the ones just saying &quot;See day whatever&quot; (and one &quot;Refer&quot;), so I plugged in some numbers. Also, it seems like the Star Trek entry should specify what's included - strange that unlike the others, it doesn't end up under a day less than the target. Also, that entry referred to/used an article which summarized CBR, I replaced it with the detailed article from CBR itself, then listed all the shows and movies, and added the things the article missed. [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 23:54, 3 July 2022 (UTC)<br /> : Great work. I wonder if Randall is counting some fan-made Trek. [[Special:Contributions/172.70.211.36|172.70.211.36]] 01:10, 5 July 2022 (UTC)</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2641:_Mouse_Turbines&diff=288243 2022-07-05T00:28:03Z

<p>172.70.211.36: /* Explanation */ wishing link</p> <hr /> <div>{{comic<br /> | number = 2641<br /> | date = July 4, 2022<br /> | title = Mouse Turbines<br /> | image = mouse_turbines.png<br /> | titletext = It's sad seeing those videos of turbine blade being torn apart in high winds, but it's the only way they can disperse their seeds.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a RENEWABLE ENERGY RODENT - Elaborate on the title text. Do NOT delete this tag too soon.}}<br /> <br /> [[Beret Guy]] and [[Megan]] are walking in summer, where Beret Guy expresses his appreciation for typical features of a summer day. He also mentions &quot;wind turbines&quot; put up by field mice, which Megan initially assumes to be referring to dandelions (similar to the wordplay that Beret Guy utilized in [[1322: Winter]]). However, Beret Guy turns out to be speaking literally, as he picks up what is in fact a tiny {{w|wind turbine}}, asks Megan to [https://www.dandelionpress.com/dandelion-blog/2015/4/6/how-to-wish-on-a-dandelion make a wish,] and blows into it. This causes the blades of the turbine to spin very rapidly, generating a lot of power for the structure it is connected to, thus causing a field mouse to cheer in excitement.<br /> <br /> Sadly, the power output per size of wind turbines increases with their size,[https://www.energy.gov/eere/articles/wind-turbines-bigger-better] a limitation not shared by other forms of renewable energy such as {{w|solar panel}}s and {{w|pico hydro}}. According to [https://www.omnicalculator.com/ecology/wind-turbine this calculator], a 10 centimeter radius wind turbine powered by a 5.7 meter/second breath[https://www.sciencedirect.com/science/article/pii/S2215098616300830] would produce one watt at just 26% efficiency.<br /> <br /> Further frustrating mouse use of wind power, {{w|Wind gradient|windspeed increases logarithmically with height}} above ground. Windspeed is reported as its value 10 meters above ground, where it is 1.5 times faster than at ground level.[https://www.nooutage.com/wind.htm] In the U.S., where Randall lives, average year-round windspeed is about 15 km/h,[https://sciencing.com/average-daily-wind-speed-24011.html] or about 2.8 m/s at ground level, yielding only 0.11 watts for such turbines. However, a typical mouse weighs 25 grams,[https://web.jhu.edu/animalcare/procedures/mouse.html] compared to about 81 kilograms for humans in the U.S.,[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3408371/] so presumably mice electricity needs would be about 0.03% of people's. The average U.S. residential customer uses 1,242 watts of electricity,[https://www.electricchoice.com/blog/electricity-on-average-do-homes/] 0.03% of which is 0.37 watts. Therefore, three such turbines could be able to serve about 89% of a mouse's needs. While this figure does not account for necessary {{w|home energy storage}} efficiency overhead, mice usually live much less extravagantly than typical Americans,{{citation needed}} so three turbines should be sufficient.<br /> <br /> The title text claims wind turbines reproduce by dispersing their blades, in the manner of dandelion {{w|seed dispersal}}. Randall's suggestion of turbine seeds conflicts with Beret Guy's assertion that the turbines were built by field mice.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Megan and Beret Guy are walking on grass.]<br /> :Beret Guy: Ahh, summer!<br /> :Beret Guy: The clouds are big, the bugs are zooming,<br /> <br /> :[Beret Guy stops walking. There are three small trefoil structures and a tiny building on the grass in front of him.]<br /> :Beret Guy: and the field mice have put up their little wind turbines.<br /> <br /> :[Beret Guy picks up one of the turbines. Under the turbine there is a wire attached to the ground.]<br /> :Megan (off-panel): You mean dandelions?<br /> :Beret Guy: No.<br /> <br /> :[Beret Guy holds the turbine in front of him.]<br /> :Beret Guy: Make a wish!<br /> <br /> :[Beret Guy blows into the turbine blades and makes them spin. The wire transfers electricity towards the ground.]<br /> :''Puff''<br /> :⚡ ⚡ ⚡ ⚡<br /> :Voice at ground level: Yaaay!<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Comics featuring Megan]]<br /> [[Category:Comics featuring Beret Guy]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2641:_Mouse_Turbines&diff=288204 2022-07-04T22:02:53Z

<p>172.70.211.36: /* Explanation */ damnit I did it again. Someone please check my math</p> <hr /> <div>{{comic<br /> | number = 2641<br /> | date = July 4, 2022<br /> | title = Mouse Turbines<br /> | image = mouse_turbines.png<br /> | titletext = It's sad seeing those videos of turbine blade being torn apart in high winds, but it's the only way they can disperse their seeds.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a RENEWABLE ENERGY RODENT - Elaborate on the title text. Do NOT delete this tag too soon.}}<br /> <br /> [[Beret Guy]] and [[Megan]] are walking in summer, where Beret Guy expresses his appreciation for the weather typical of a summer day. He also mentions &quot;field mice's wind turbines&quot;, which Megan initially assumes to be referring to dandelions (similar to the wordplay that Beret Guy utilized in [[1322: Winter]]). However, Beret Guy turns out to be speaking literally, as he picks up what is in fact a tiny {{w|wind turbine}} and blows into it. This causes the blades of the turbine to spin very rapidly, generating a lot of power for the structure it is connected to, thus causing the field mice to cheer in excitement.<br /> <br /> Sadly, the efficiency of wind turbines is proportional to their size,[https://www.energy.gov/eere/articles/wind-turbines-bigger-better] a limitation not shared by other forms of renewable energy such as {{w|solar panel}}s and {{w|pico hydro}}. According to [https://www.omnicalculator.com/ecology/wind-turbine this calculator], a 10 centimeter radius wind turbine powered by a 5.7 meter/second breath[https://www.sciencedirect.com/science/article/pii/S2215098616300830] would produce one watt at just 26% efficiency.<br /> <br /> Further frustrating mice using wind power, {{w|Wind gradient|windspeed increases logarithmically with height}} above ground. Windspeed is published as its value 10 meters above ground, where it is 1.5 times faster than at ground level.[https://www.nooutage.com/wind.htm] In the U.S., where Randall lives, average year-round windspeed is about 15 km/h,[https://sciencing.com/average-daily-wind-speed-24011.html], or about 2.8 m/s at ground level, yielding only 0.1 watt for such turbines. However, a typical mouse weighs 25 grams,[https://web.jhu.edu/animalcare/procedures/mouse.html] compared to about 81 kilograms for humans,[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3408371/] so presumably mice electricity needs would be about 0.03% of people. The average U.S. residential customer uses about 1,242 watts of electricity,[https://www.electricchoice.com/blog/electricity-on-average-do-homes/] 0.03% of which is 0.4 watts. Therefore, three such turbines should be able to serve most of one mouse's needs, assuming their {{w|home energy storage}} batteries are not too inefficient.<br /> <br /> The title text claims wind turbines reproduce by dispersing their blades, in the manner of dandelion {{w|seed dispersal}}.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Megan and Beret Guy are walking on grass.]<br /> :Beret Guy: Ahh, summer!<br /> :Beret Guy: The clouds are big, the bugs are zooming,<br /> <br /> :[Beret Guy stops walking. There are tiny structures on the grass in front of him.]<br /> :Beret Guy: and the field mice have put up their little wind turbines.<br /> <br /> :[Beret Guy picks up one of the turbines. Under the turbine there is a wire attached to the ground.]<br /> :Megan (off-panel): You mean dandelions?<br /> :Beret Guy: No.<br /> <br /> :[Beret Guy holds the turbine in front of him.]<br /> :Beret Guy: Make a wish!<br /> <br /> :[Beret Guy blows into the turbine blades and makes them spin. The wire transfers electricity towards the ground.]<br /> :''Puff''<br /> :⚡ ⚡ ⚡ ⚡<br /> :Voice below the ground: Yaaay!<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Comics featuring Megan]]<br /> [[Category:Comics featuring Beret Guy]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2641:_Mouse_Turbines&diff=288203 2022-07-04T21:59:13Z

<p>172.70.211.36: /* Explanation */ ooof, I got a decimal place wrong</p> <hr /> <div>{{comic<br /> | number = 2641<br /> | date = July 4, 2022<br /> | title = Mouse Turbines<br /> | image = mouse_turbines.png<br /> | titletext = It's sad seeing those videos of turbine blade being torn apart in high winds, but it's the only way they can disperse their seeds.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a RENEWABLE ENERGY RODENT - Elaborate on the title text. Do NOT delete this tag too soon.}}<br /> <br /> [[Beret Guy]] and [[Megan]] are walking in summer, where Beret Guy expresses his appreciation for the weather typical of a summer day. He also mentions &quot;field mice's wind turbines&quot;, which Megan initially assumes to be referring to dandelions (similar to the wordplay that Beret Guy utilized in [[1322: Winter]]). However, Beret Guy turns out to be speaking literally, as he picks up what is in fact a tiny {{w|wind turbine}} and blows into it. This causes the blades of the turbine to spin very rapidly, generating a lot of power for the structure it is connected to, thus causing the field mice to cheer in excitement.<br /> <br /> Sadly, the efficiency of wind turbines is proportional to their size,[https://www.energy.gov/eere/articles/wind-turbines-bigger-better] a limitation not shared by other forms of renewable energy such as {{w|solar panel}}s and {{w|pico hydro}}. According to [https://www.omnicalculator.com/ecology/wind-turbine this calculator], a 10 centimeter radius wind turbine powered by a 5.7 meter/second breath[https://www.sciencedirect.com/science/article/pii/S2215098616300830] would produce one watt at just 26% efficiency.<br /> <br /> Further frustrating mice using wind power, {{w|Wind gradient|windspeed increases logarithmically with height}} above ground. Windspeed is published as its value 10 meters above ground, where it is 1.5 times faster than at ground level.[https://www.nooutage.com/wind.htm] In the U.S., where Randall lives, average year-round windspeed is about 15 km/h,[https://sciencing.com/average-daily-wind-speed-24011.html], or about 2.8 m/s at ground level, yielding only 0.1 watt for such turbines. However, a typical mouse weighs 25 grams,[https://web.jhu.edu/animalcare/procedures/mouse.html] compared to about 81 kilograms for humans,[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3408371/] so presumably mice electricity needs would be about 0.03% of people. The average U.S. residential customer uses about 1,242 watts of electricity,[https://www.electricchoice.com/blog/electricity-on-average-do-homes/] 0.03% of which is 3.7 watts. Therefore, three such turbines might only be able to serve a twelfth of a mouse's needs, less their {{w|home energy storage}} battery overhead.<br /> <br /> The title text claims wind turbines reproduce by dispersing their blades, in the manner of dandelion {{w|seed dispersal}}.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Megan and Beret Guy are walking on grass.]<br /> :Beret Guy: Ahh, summer!<br /> :Beret Guy: The clouds are big, the bugs are zooming,<br /> <br /> :[Beret Guy stops walking. There are tiny structures on the grass in front of him.]<br /> :Beret Guy: and the field mice have put up their little wind turbines.<br /> <br /> :[Beret Guy picks up one of the turbines. Under the turbine there is a wire attached to the ground.]<br /> :Megan (off-panel): You mean dandelions?<br /> :Beret Guy: No.<br /> <br /> :[Beret Guy holds the turbine in front of him.]<br /> :Beret Guy: Make a wish!<br /> <br /> :[Beret Guy blows into the turbine blades and makes them spin. The wire transfers electricity towards the ground.]<br /> :''Puff''<br /> :⚡ ⚡ ⚡ ⚡<br /> :Voice below the ground: Yaaay!<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Comics featuring Megan]]<br /> [[Category:Comics featuring Beret Guy]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2641:_Mouse_Turbines&diff=288198 2022-07-04T21:33:15Z

<p>172.70.211.36: /* Explanation */ ground wind speed yeild</p> <hr /> <div>{{comic<br /> | number = 2641<br /> | date = July 4, 2022<br /> | title = Mouse Turbines<br /> | image = mouse_turbines.png<br /> | titletext = It's sad seeing those videos of turbine blade being torn apart in high winds, but it's the only way they can disperse their seeds.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a RENEWABLE ENERGY RODENT - Elaborate on the title text. Do NOT delete this tag too soon.}}<br /> <br /> [[Beret Guy]] and [[Megan]] are walking in summer, where Beret Guy expresses his appreciation for the weather typical of a summer day. He also mentions &quot;field mice's wind turbines&quot;, which Megan initially assumes to be referring to dandelions (similar to the wordplay that Beret Guy utilized in [[1322: Winter]]). However, Beret Guy turns out to be speaking literally, as he picks up what is in fact a tiny {{w|wind turbine}} and blows into it. This causes the blades of the turbine to spin very rapidly, generating a lot of power for the structure it is connected to, thus causing the field mice to cheer in excitement.<br /> <br /> Sadly, the efficiency of wind turbines is proportional to their size,[https://www.energy.gov/eere/articles/wind-turbines-bigger-better] a limitation not shared by other forms of renewable energy such as {{w|solar panel}}s and {{w|pico hydro}}. According to [https://www.omnicalculator.com/ecology/wind-turbine this calculator], a 10 centimeter radius wind turbine powered by a 5.7 meter/second breath[https://www.sciencedirect.com/science/article/pii/S2215098616300830] would produce one watt at just 26% efficiency.<br /> <br /> Further frustrating mice using wind power, {{w|Wind gradient|windspeed increases logarithmically with height}} above ground. Windspeed is published as its value 10 meters above ground, where it is 1.5 times faster than at ground level.[https://www.nooutage.com/wind.htm] In the U.S., where Randall lives, average year-round windspeed is about 15 km/h, or 2.8 m/s at ground level,[https://sciencing.com/average-daily-wind-speed-24011.html] yielding only 0.1 watt for such turbines.<br /> <br /> The title text claims wind turbines reproduce by dispersing their blades, in the manner of dandelion {{w|seed dispersal}}.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Megan and Beret Guy are walking on grass.]<br /> :Beret Guy: Ahh, summer!<br /> :Beret Guy: The clouds are big, the bugs are zooming,<br /> <br /> :[Beret Guy stops walking. There are tiny structures on the grass in front of him.]<br /> :Beret Guy: and the field mice have put up their little wind turbines.<br /> <br /> :[Beret Guy picks up one of the turbines. Under the turbine there is a wire attached to the ground.]<br /> :Megan (off-panel): You mean dandelions?<br /> :Beret Guy: No.<br /> <br /> :[Beret Guy holds the turbine in front of him.]<br /> :Beret Guy: Make a wish!<br /> <br /> :[Beret Guy blows into the turbine blades and makes them spin. The wire transfers electricity towards the ground.]<br /> :''Puff''<br /> :⚡ ⚡ ⚡ ⚡<br /> :Voice below the ground: Yaaay!<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Comics featuring Megan]]<br /> [[Category:Comics featuring Beret Guy]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=Talk:2641:_Mouse_Turbines&diff=288186 2022-07-04T20:46:29Z

<p>172.70.211.36: Typo</p> <hr /> <div>&lt;!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--&gt;<br /> Is anybody going to try to calculate the amount of power such a turbine could collect? -- [[User:Dtgriscom|Dtgriscom]] ([[User talk:Dtgriscom|talk]]) 19:24, 4 July 2022 (UTC)<br /> :Good idea; what should we use for an estimate of the geometry for https://www.omnicalculator.com/ecology/wind-turbine ? The final panel makes it look like the blade diameter is about twice the size of a fist. [https://www.sciencedirect.com/science/article/pii/S2215098616300830] says &quot;exhaled air velocity varies from 2.2 m/s to 9.9 m/s (5.66 ± 1.57 m/s, mean ± SD) and exhalation time varies from 2.10 s to 8.21 s (4.42 ± 1.73s, mean ± SD).&quot; [[Special:Contributions/172.70.206.213|172.70.206.213]] 20:38, 4 July 2022 (UTC)</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2641:_Mouse_Turbines&diff=288185 2022-07-04T20:44:59Z

<p>172.70.211.36: /* Explanation */ on second thought, this ref is useless compared to the calculator mentioned on talk</p> <hr /> <div>{{comic<br /> | number = 2641<br /> | date = July 4, 2022<br /> | title = Mouse Turbines<br /> | image = mouse_turbines.png<br /> | titletext = It's sad seeing those videos of turbine blade being torn apart in high winds, but it's the only way they can disperse their seeds.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a RENEWABLE ENERGY RODENT - Elaborate on the title text. Do NOT delete this tag too soon.}}<br /> <br /> [[Beret Guy]] and [[Megan]] are walking in summer, where Beret Guy expresses his appreciation for the weather typical of a summer day. He also mentions &quot;field mice's wind turbines&quot;, which Megan initially assumes to be referring to dandelions (similar to the wordplay that Beret Guy utilized in [[1322: Winter]]). However, Beret Guy turns out to be speaking literally, as he picks up what is in fact a tiny {{w|wind turbine}} and blows into it. This causes the blades of the turbine to spin very rapidly, generating a lot of power for the structure it is connected to, thus causing the field mice to cheer in excitement.<br /> <br /> Sadly, the efficiency of wind turbines is proportional to their size,[https://www.energy.gov/eere/articles/wind-turbines-bigger-better] a limitation not shared by other forms of renewable energy such as {{w|solar panel}}s and {{w|pico hydro}}. <br /> <br /> The title text claims wind turbines reproduce by dispersing their blades, in the manner of dandelion {{w|seed dispersal}}.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> :[Megan and Beret Guy are walking on grass.]<br /> :Beret Guy: Ahh, summer!<br /> :Beret Guy: The clouds are big, the bugs are zooming,<br /> <br /> :[Beret Guy stops walking. There are tiny structures on the grass in front of him.]<br /> :Beret Guy: and the field mice have put up their little wind turbines.<br /> <br /> :[Beret Guy picks up one of the turbines. Under the turbine there is a wire attached to the ground.]<br /> :Megan (off-panel): You mean dandelions?<br /> :Beret Guy: No.<br /> <br /> :[Beret Guy holds the turbine in front of him.]<br /> :Beret Guy: Make a wish!<br /> <br /> :[Beret Guy blows into the turbine blades and makes them spin. The wire transfers electricity towards the ground.]<br /> :''Puff''<br /> :⚡ ⚡ ⚡ ⚡<br /> :Voice below the ground: Yaaay!<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Comics featuring Megan]]<br /> [[Category:Comics featuring Beret Guy]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=Talk:2641:_Mouse_Turbines&diff=288184 2022-07-04T20:43:50Z

<p>172.70.211.36: Breath power</p> <hr /> <div>&lt;!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--&gt;<br /> Is anybody going to try to calculate the amount of power such a turbine could collect? -- [[User:Dtgriscom|Dtgriscom]] ([[User talk:Dtgriscom|talk]]) 19:24, 4 July 2022 (UTC)<br /> :Good idea; what should we use for an estimate of the geometry for https://www.omnicalculator.com/ecology/wind-turbine ? The final panel makes it look like the blade diameter is about twice the size of a fist. [https://www.sciencedirect.com/science/article/pii/S2215098616300830] says &quot;exhaled air velocity varies from 2.2 m/s to 9.9 m/s with (5.66 ± 1.57 m/s, mean ± SD) and exhalation time varies from 2.10 s to 8.21 s (4.42 ± 1.73s, mean ± SD).&quot; [[Special:Contributions/172.70.206.213|172.70.206.213]] 20:38, 4 July 2022 (UTC)</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2636:_What_If%3F_2_Countdown&diff=288108 2022-07-03T01:35:57Z

<p>172.70.211.36: Explicit order of operations for multiple exponentiation</p> <hr /> <div>{{comic<br /> | number = 2636<br /> | date = June 22, 2022<br /> | title = What If? 2 Countdown<br /> | image = what_if_2_countdown.png<br /> | titletext = If you don't end the 99 Bottles of Beer recursion at N=0 it just becomes The Other Song That Never Ends.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by FOUR SCORE AND 7 BOTTLES OF BEER ON THE WALL - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> This comic takes the idea of {{w|advent calendar}}s to the extreme. It uses absurd and obscure ways to measure the amount of time until [[Randall]]'s new book [https://xkcd.com/whatif2 ''What if? 2''] is released, with esoteric units and esoteric numbers.<br /> <br /> Some concepts that appear multiple times throughout the calendar are:<br /> <br /> * '''{{w|SI prefixes}}''', which can be applied to the beginning of a unit's name to multiply or divide the unit by powers of 10 or 1,000. This is standard for units like meters and grams, but is rarely applied to measurements of time other than when a unit of less than one second is needed, most commonly in various fields of science and engineering such as physics and electronics.<br /> * The '''{{w|Gettysburg Address}}''', a famous speech delivered by U.S. president Abraham Lincoln in 1863, where he began by referring to the signing of the Declaration of Independence taking place &quot;four score and seven years ago&quot;. A score is a dated term for the number 20, so &quot;four score and seven&quot; is equivalent to 87.<br /> * A '''dog year''' is traditionally considered to be one-seventh the length of a normal human year, since a dog's overall lifespan is roughly one-seventh of a typical human's. The comic applies this to other units of time, such as minutes and months, each of which is also one-seventh the length of the standard unit. The number 7 (traditionally a &quot;lucky number&quot;) is also used in many of the numbers quoted in the calendar.<br /> * Other comparative durations of time that are not normally or usefully applied to day-length multiples. At the top end, there is the age of the universe, at the other there is {{w|Planck units#Planck time|Planck-time}} – with entire durations of periods of human history and the time needed to watch popular TV/film franchises in-between – most of which require a non-trivial multiplier or divisor to bring them to the necessary scale required. <br /> * A '''{{w|baker's dozen}}''' is 13, or one more than a normal dozen. Here, the &quot;baker's&quot; prefix can be applied to any unit by adding an extra one of its constituent parts, like an extra hour added to a day.<br /> * '''{{w|Irrational numbers}}''' like {{w|pi}} (3.14159...), {{w|Euler's number}} or ''e'' (2.71828...), the {{w|golden ratio}} (1.61803...), and the {{w|square root of 2}} (1.41421...). These are all interesting numbers because of their mathematical properties, but very impractical to use as arbitrary measurements of time because they have an endless series of non-repeating decimal digits.<br /> * The teenage dating game '''{{w|Seven minutes in heaven}}'''. <br /> * Rotational and orbital periods of various bodies in the Solar System.<br /> <br /> {| class=&quot;wikitable&quot;<br /> |-<br /> ! Days left !! Date !! Duration specified !! Duration in days !! Explanation<br /> |-<br /> | 83 || Jun 22 || π&lt;sup&gt;e&lt;/sup&gt; millidecades || 82.03&amp;nbsp;days || π ≈ 3.14159, ''e'' ≈ 2.718, so π&lt;sup&gt;e&lt;/sup&gt; is about 22.459. A millidecade is 1/1000 decade, or 1/100 year, or 3.652425 days. Multiplying these results in 82.03 days. This is a play on {{w|Euler's identity}}, e&lt;sup&gt;iπ&lt;/sup&gt;+1=0, but raising pi to the power of ''e'' instead.<br /> |-<br /> | 82 || Jun 23 || 7 megaseconds || 81.02 days || 7,000,000 seconds. 60*60*24 = 86400 seconds in a day, so 7,000,000/86,400 ≈ 81.02 days<br /> |-<br /> | 81 || Jun 24 || ''e'' lunar months || 80.27 days || A lunar month ≈ 29.53059 days, ''e'' ≈ 2.718, so 29.53059*2.718 ≈ 80.26 days.<br /> |-<br /> | 80 || Jun 25 || 60 rotations of Foucault's pendulum in Paris || 79.67 days || {{w|Foucault's pendulum}} demonstrates Earth's revolution, with the one at the latitude of Paris completing a full rotation every 31.8 hours.&lt;!-- no need to give the whole history and operation of Foucault's pendulum here; that's what the Wikipedia link is for --&gt;<br /> |-<br /> | 79 || Jun 26 || 8 milligenerations || 78.89 days || A generation is in general 22-33 years, with a reasonable mid-point of 27; and 8 x 0.001 (milli) x 365.2425 (accounting for leap years) x 27 ≈ 78.89 days<br /> |-<br /> | 78 || Jun 27 || 777,777 dog minutes || 77.16 days || A popular myth is that dogs age 7 times faster than humans, so 1 dog minute equals 1/7 human minutes. <br /> |-<br /> | 77 || Jun 28 || 7! episodes of ''Jeopardy!'' (skipping ads) || 77+ days || 7! = 7x6x5x4x3x2x1 = 5040. The standard episode of ''Jeopardy'' is 22-26 minutes, skipping ads. At 22 minutes each, the total is 110,880 minutes, or exactly 77 days.<br /> |-<br /> | 76 || Jun 29 || 5,000 repeats of ''99 Bottles of Beer'' || 76.39 days || Each verse of {{w|99 Bottles of Beer}} is &quot;''N'' bottles of beer on the wall, ''N'' bottles of beer. Take one down, pass it around, ''N-1'' bottles of beer on the wall.&quot; The entire song contains 99 verses. Randall apparently sings this rather slowly at around 72 bpm, taking about 13 seconds per verse. <br /> |-<br /> | 75 || Jun 30 || 5 baker's fortnights || 75 days || A {{w|baker's dozen}} is a dozen (12) plus 1 extra item. Randall has generalized this to adding 1 to any unit. A fortnight is 14 days (or more properly &quot;{{w|Fortnight|fourteen ''nights''}}&quot;, by its original use), so a baker's fortnight is 15 days. 5x15 is 75 days.<br /> |-<br /> | 74 || Jul 1 || √2 dog years || 73.79 days || See day 78 (Jun 27)<br /> |-<br /> | 73 || Jul 2 || π millivics (1/1000th of Queen Victoria's reign) || 72.97 days || {{w|Queen Victoria}} ruled between 20 June 1837 and 22 January 1901 (23,226 days). <br /> |-<br /> | 72 || Jul 3 || 42 drives from NYC to LA (Google Maps estimate) || 71.75 days || According to Google Maps, the drive from New York City to Los Angeles via I-80 W (2789 miles or 4489 km) takes 41 hours.<br /> |-<br /> | 71 || Jul 4 || 1,000 viewings of ''Groundhog Day''|| 70.14 days || Using {{w|Groundhog Day (film)|Groundhog Day's}} 101-minute run time. <br /> |-<br /> | 70 || Jul 5 || 100,000 minutes || 69.44 days || 1,440 minutes per day<br /> |-<br /> | 69 || Jul 6 || 1/10th of Martian year || 68.70 Earth days || Martian sidereal and tropical years both round to 687.0 Earth days<br /> |-<br /> | 68 || Jul 7 || 1,234,567 sound-miles || 67.63 days || The speed of sound in air depends on the temperature. 15 °C or 59 °F gives the value 340 m/s and the travel time of 67.6349058 days.<br /> |-<br /> | 67 || Jul 8 || 2&lt;sup&gt;π&lt;sup&gt;e&lt;/sup&gt;&lt;/sup&gt; seconds || 66.74 days || 2^(π^e) = 5,766,073 seconds. The order of operations for multiple exponentiation without parentheses is top-first.<br /> |-<br /> | 66 || Jul 9 || 2&lt;sup&gt;16&lt;/sup&gt; beats (Swatch Internet Time) || 65.54 days || A &quot;{{w|.beat}}&quot; is equal to 1/1000 day.<br /> |-<br /> | 65 || Jul 10 || 1,000 ISS orbits || 64.58 days || Each orbit of the ISS takes 90-93 minutes. Here a value of 93 minutes is used.<br /> |-<br /> | 64 || Jul 11 || 🎵🎶🎵 Five hundred twenty five thousand (base seven) minutes|| 62.88 days || This refers to {{w|radix}}-7 arithmetic: 525,000&lt;sub&gt;7&lt;/sub&gt; minutes = 90,552&lt;sub&gt;10&lt;/sub&gt; minutes. Also references the opening and recurring line &quot;Five hundred twenty five thousand six hundred minutes&quot; from {{w|Seasons of Love}}, a song from the musical {{w|Rent (musical)|''Rent''}}, which is also referenced in [[1047: Approximations]]. &quot;Base seven&quot; has the same rhythm as &quot;six hundred&quot;.<br /> |-<br /> | 63 || Jul 12 || 10&lt;sup&gt;50&lt;/sup&gt; Planck times || 62.38 days || 10^50 x 5.39 x 10^-44 seconds<br /> |-<br /> | 62 || Jul 13 || 4,000 episodes of ''The Office'' (skipping ads)|| 62.50 days || {{w|The Office (British TV series)|''The Office''}} was originally a {{w|BBC}} television show which had no commercial breaks, so Randall must be referring to the later {{w|The Office (American TV series)|US version}}. This US &quot;half-hour&quot; comedy format contains 22.5 minutes of content (including the title sequence) and 7.5 minutes of ads. There are only 201 distinct episodes of the US version, so watching 4,000 episodes would require a lot of re-watching. &lt;!-- When you get here, note that the original The Office was on the BBC in the UK and had no ads and thus filled its allocated broadcasting slot, give or take intro/follow-on announcements... Only the US adaptation/remake has ads to be skipped. So link the 'correct' one (from Randall's POV, at least). --&gt;<br /> |-<br /> | 61 || Jul 14 || Four score and seven kilominutes || 60.42 days || 87 x 1000 minutes<br /> |-<br /> | 60 || Jul 15 || 2 lunar months || 59.06 days || There are a number of different ways to define the {{w|lunar month}}. The most common is the synodic month, because it relates to the phases of the moon, and it's approximately 29.53 days.<br /> |-<br /> | 59 || Jul 16 || Half a day on Venus || 58.38 Earth days || A Venus synodic day is 116 days 18 hours.<br /> |-<br /> | 58 || Jul 17 || 5 megaseconds || 57.87 days || 5,000,000 seconds<br /> |-<br /> | 57 || Jul 18 || 30 microLits (1/1,000,000th of the time since the invention of literature) || 57.21 days || 5222 years &amp;times; 30 &amp;times; 10&lt;sup&gt;-6&lt;/sup&gt;. 3200 BCE is the approximate date of pre-Sumerian proto-writing as given in {{w|History of writing|Wikipedia's article on the history of writing}}.<br /> |-<br /> | 56 || Jul 19 || 1,000 viewings of ''Run Lola Run'' || 55.57 days || Using {{w|Run Lola Run|the movie's}} run time of 80 minutes.<br /> |-<br /> | 55 || Jul 20 || One million sound-miles || 54.78 days || The speed of sound in air depends on the temperature. 15 °C or 59 °F gives the value 340 m/s and the travel time of 54.7843137 days.<br /> |-<br /> | 54 || Jul 21 || 30 Ionian months || 53.07 Earth days || Orbital period of Io around Jupiter is approximately 1.77 days.<br /> |-<br /> | 53 || Jul 22 || One dog year || 52.18 days || See day 78 (Jun 27)<br /> |-<br /> | 52 || Jul 23 || 60 viewings of ''Star Wars Episodes I-IX'' || 51.75 days || According to [https://dorksideoftheforce.com/2021/05/04/how-long-to-watch-every-star-wars-movie/ Fansided] the combined running times are 20 hours 42 minutes.<br /> |-<br /> | 51 || Jul 24 || 1/100,000,000,000th of the universe's age || 50.40 days || The universe is estimated to be about 13.8 billion years old.<br /> |-<br /> | 50 || Jul 25 || 5 milli-generations || 49.3 days || See day 79 (Jun 26)<br /> |-<br /> | 49 || Jul 26 || 10,000 games of ''7 minutes in Heaven'' or 7 games of ''10,000 minutes in Heaven'' || 48.61 days || {{w|Seven minutes in heaven}} is an Anglo-culture teenager game, occuring in several movies. 10,000 minutes in Heaven is almost a week of making out (or doing whatever) in a closet, so this game is unlikely.{{citation needed}}<br /> |-<br /> | 48 || Jul 27 || φ&lt;sup&gt;e&lt;sup&gt;π&lt;/sup&gt;&lt;/sup&gt; minutes || 47.62 days || 68,567.57 minutes<br /> |-<br /> | 47 || Jul 28 || 4 megaseconds || 46.30 days || 4,000,000 seconds<br /> |-<br /> | 46 || Jul 29 || 2&lt;sup&gt;16&lt;/sup&gt; minutes || 45.51 days || 65,536 minutes<br /> |-<br /> | 45 || Jul 30 || e&lt;sup&gt;e&lt;sup&gt;e&lt;/sup&gt;&lt;/sup&gt; seconds || 44.15 days || 3,814,279.10 seconds<br /> |-<br /> | 44 || Jul 31 || π fortnights|| 43.98 days || 3.14159 x 14 days<br /> |-<br /> | 43 || Aug 1 || One devil's spacewalk (666 orbits of the ISS) || 43.01 days || See day 65 (Jul 10). 666 is the {{w|number of the beast}}.<br /> |-<br /> | 42 || Aug 2 || 1 kilowatt-hour per watt || 41.66 days || 1000 hours<br /> |-<br /> | 41 || Aug 3 || e&lt;sup&gt;π&lt;/sup&gt; Ionian months || 40.94 Earth days || Orbital period of Io around Jupiter is 1.769137786 days<br /> |-<br /> | 40 || Aug 4 || 30 rotations of Foucault's pendulum in Paris || 39.84 days || Refer to Day 80 (Jun 25)<br /> |-<br /> | 39 || Aug 5 || ''e'' fortnights || 38.06 days ||2.71828 x 14 days<br /> |-<br /> | 38 || Aug 6 || π&lt;sup&gt;e&lt;/sup&gt; baker's days (25 hours) || 37.98 days || See day 75 (Jun 30)<br /> |-<br /> | 37 || Aug 7 || One deciyear || 36.52 days || One tenth of one year<br /> |-<br /> | 36 || Aug 8 || 7! milliweeks || 35.28 days || 5040 × 0.001 weeks <br /> |-<br /> | 35 || Aug 9 || 100,000 plays of the ''Jeopardy!'' &quot;Think&quot; music || 34.72 days || ''Think'' is the music played while the contestants try to answer the Final Jeopardy question; it is 30 seconds long.<br /> |-<br /> | 34 || Aug 10 || 1000 basketball games (game time) || 33.33 days || Uses the NBA game time of four 12-minute quarters, or 48 minutes<br /> |-<br /> | 33 || Aug 11 || 777 hours || 32.38 days || 24 hours per day<br /> |-<br /> | 32 || Aug 12 || One millilincoln (1/1000 of fourscore and seven years) || 31.78 days || {{w|Abraham Lincoln}}'s {{w|Gettysburg Address}} begins with the famous phrase &quot;Four score and seven years ago&quot;. 1 score = twenty. &lt;!-- in this case, of years, but 'years' is already after the &quot;four score and seven&quot;, so redundant and somewhat wrong --&gt;<br /> |-<br /> | 31 || Aug 13 || 1,000 episodes of ''60 Minutes'' (skipping ads) || 31.25 days || Uses a television 'hour' containing 45 minutes of content and 15 minutes of ads<br /> |-<br /> | 30 || Aug 14 || All of ''Star Trek'', consecutively || 27.16* days || As per [https://redshirtsalwaysdie.com/2021/01/22/take-far-longer-watch-star-trek-think/ RedShirtsAlwaysDie.com] of January 22, 2021. *Note well: dozens of additional ''Star Trek'' franchise episodes have been produced since, and more are presently scheduled to be released through June, July, and August, so this value is somewhat indeterminate over the scope of the countdown.<br /> |-<br /> | 29 || Aug 15 || 777,777 nanocenturies || 28.41 days || 777,777 × 10&lt;sup&gt;-9&lt;/sup&gt; × 100 years.<br /> |-<br /> | 28 || Aug 16 || One sidereal lunar month || 27.3 days || The time it takes moon to return to the same position relative to the fixed stars<br /> |-<br /> | 27 || Aug 17 || 6 dog months || 26.1 days || See day 78 (Jun 27)<br /> |-<br /> | 26 || Aug 18 || π&lt;sup&gt;π&lt;/sup&gt; kilominutes || 25.32 days || 36,462.16 minutes<br /> |-<br /> | 25 || Aug 19 || 7 games of 7! minutes in Heaven || 24.5 days || 7 x 5040 (7 {{w|factorial}}) minutes. See also day 49 (Jul 26).<br /> |-<br /> | 24 || Aug 20 || 50 viewings of the extended ''Lord of the Rings'' trilogy || 23.82 days || ''The Fellowship of the Ring'' extended version is 208 minutes, ''The Two Towers'' is 226 minutes, and ''The Return of the King'' is 252 minutes for its extended version, according to [https://fictionhorizon.com/how-long-are-all-the-lord-of-the-rings-and-the-hobbit-movies-combined/ FictionHorizon.com] <br /> |-<br /> | 23 || Aug 21 || A drive from NYC to LA where you keep remembering new things you forgot and have to go back 6 times || 22.21 days || See day 72 (Jul 3). This is for 6 round-trips and 1 one-way trip.&lt;!-- is this a reference to something? --&gt;<br /> |-<br /> | 22 || Aug 22 || ''It's a Small World'' sung at 1/10,000th speed || 21.18 days || {{w|It's a Small World}} is a song that was composed for the attraction of the same name at various {{w|Disney}} theme parks, and plays continuously at them in various languages. The song lasts 12–15 minutes, depending on the language.<br /> |-<br /> | 21 || Aug 23 || 500 hours || 20.83 days || 24 hours per day, or 0.041678 days per hour<br /> |-<br /> | 20 || Aug 24 || √2 fortnights || 19.80 days || 1.4142 × 14 days<br /> |-<br /> | 19 || Aug 25 || Time it would take Vanessa Carlton to walk 1,000 miles || 18.94 days || {{w|Vanessa Carlton}} is an American singer, and {{w|A Thousand Miles}} is her most successful song. Randall estimates her walking speed at about 2.2 miles/hour.<br /> |-<br /> | 18 || Aug 26 || 100,000 breaths || 17.36** days || The normal respiratory rate for adults is typically 12-20 breaths per minute, or about 3-5 seconds each. **However, the day length here is for 15 seconds/breath, so Randall may be a practitioner of [https://www.frontiersin.org/articles/10.3389/fnhum.2018.00353/full slow breathing]. <br /> |-<br /> | 17 || Aug 27 || √2 megaseconds || 16.37 days || 1.4142 × 1,000,000 seconds<br /> |-<br /> | 16 || Aug 28 || π&lt;sup&gt;π&lt;sup&gt;π&lt;/sup&gt;&lt;/sup&gt; πcoseconds || 15.51 days || 1.3402 × 10&lt;sup&gt;18&lt;/sup&gt; picoseconds (i.e., 10&lt;sup&gt;-12&lt;/sup&gt; seconds), making a joke how the mathematical &quot;pi&quot; is written with the character &quot;π&quot;<br /> |-<br /> | 15 || Aug 29 || One baker's fortnight (15 days) || 15 days || See day 75 (Jun 30)<br /> |-<br /> | 14 || Aug 30 || One baker's dozen (13) baker's days (25 hours) || 13.54 days || 325 hours; see day 75 (Jun 30)<br /> |-<br /> | 13 || Aug 31 || 300 hours || 12.5 days || 0.041678 days per hour<br /> |-<br /> | 12 || Sep 1 || One million seconds || 11.57 days || 86,400 seconds per day<br /> |-<br /> | 11 || Sep 2 || One nonstop bike ride from NYC to LA || 10.54 days || Google maps estimates the trip at 253 hours<br /> |-<br /> | 10 || Sep 3 || &lt;sup&gt;1&lt;/sup&gt;⁄&lt;sub&gt;1,000&lt;/sub&gt;th of a generation || 9.86 days || See day 79 (Jun 26)<br /> |-<br /> | 9 || Sep 4 || 777,777 seconds || 9.002 days || 1.15741&amp;times;10&lt;sup&gt;-5&lt;/sup&gt; days per second<br /> |-<br /> | 8 || Sep 5 || 100 viewings of ''Groundhog Day'' || 7.01 days || See Day 71 (Jul 4). <br /> |-<br /> | 7 || Sep 6 || 100 games of ''Lincoln Kissing'' (fourscore and seven minutes in Heaven) || 6.04 days || 8,700 minutes<br /> |-<br /> | 6 || Sep 7 || One pico-universe-lifetime || 5.04 days || See Day 51 (Jul 24)<br /> |-<br /> | 5 || Sep 8 || The ''Baby Shark'' chorus for a family of 50,000 sharks || 4.63 days || The chorus lasts about 8 seconds per 'person'<br /> |-<br /> | 4 || Sep 9 || One centiyear || 3.65 days || 365.2425 days/100<br /> |-<br /> | 3 || Sep 10 || Cyndi Lauper's ''Time After Time'' played 1,000 times || 2.79 days || Based on a length of 4 minutes, 1 second<br /> |-<br /> | 2 || Sep 11 || ''Speed'' (1994) played at one frame per second || 1.9 days || {{w|Speed (1994 film)}} has runtime of 116 minutes = 6,960 seconds = 167,040 film frames at standard frame rate of 24 frames/second<br /> |-<br /> | 1 || Sep 12 || F(99) where F(N) means sing all the verses of ''N Bottles of Beer On the wall'' followed by F(N-1) || 0.76 days || Each iteration contains ''N'' verses. ''N + N-1 + N-2 ... + 1'' equals ''N * (N+1) / 2'', so 99 recursions = 4950 verses. Using the same 13-second (72 bpm) rate as Jun 29, this is close to 18 hours. Probably refers to Donald Knuth's article {{w|The Complexity of Songs}}.<br /> |-<br /> | 0 || Sep&amp;nbsp;13 || ''What If? 2'' release day || N/A ||<br /> |}<br /> <br /> The title text refers to the recursive time period on Sep 12. If you don't stop when you reach N=0 bottles, the repetition never ends, so that time interval becomes infinite. He likens it to {{w|The Song That Never Ends}}, another repetitive children's song, which is specifically intended to go on forever. The difference is that the Beer song has a natural stopping point at 0, while ''The Song That Never Ends'' is completely repetitive.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> <br /> Large heading: Countdown to ''What if? 2''<br /> <br /> Subheading: (Preorder at [https://xkcd.com/whatif2 xkcd.com/whatif2] to get it at the end of the countdown)<br /> <br /> Remainder of comic is a calendar with the date in one corner of each day's box.<br /> <br /> {| class=&quot;wikitable&quot;<br /> |-<br /> ! Date !! Description <br /> |-<br /> | Jun 22 || π&lt;sup&gt;e&lt;/sup&gt; millidecades <br /> |-<br /> | Jun 23 || 7 megaseconds <br /> |-<br /> | Jun 24 || e lunar months <br /> |-<br /> | Jun 25 || 60 rotations of Foucault's pendulum in Paris <br /> |-<br /> | Jun 26 || 8 milligenerations <br /> |-<br /> | Jun 27 || 777,777 dog minutes <br /> |-<br /> | Jun 28 || 7! episodes of ''Jeopardy!'' (skipping ads) <br /> |-<br /> | Jun 29 || 5,000 repeats of ''99 Bottles of Beer'' <br /> |-<br /> | Jun 30 || 5 baker's fortnights (15 days) <br /> |-<br /> | Jul 1 || √2 dog years <br /> |-<br /> | Jul 2 || π millivics (1/1000th of Queen Victoria's reign) <br /> |-<br /> | Jul 3 || 42 drives from NYC to LA (Google Maps estimate) <br /> |-<br /> | Jul 4 || 1,000 viewings of ''Groundhog Day''<br /> |-<br /> | Jul 5 || 100,000 minutes <br /> |-<br /> | Jul 6 || 1/10th of Martian year <br /> |-<br /> | Jul 7 || 1,234,567 sound-miles <br /> |-<br /> | Jul 8 || 2&lt;sup&gt;π&lt;sup&gt;e&lt;/sup&gt;&lt;/sup&gt; seconds <br /> |-<br /> | Jul 9 || 2&lt;sup&gt;16&lt;/sup&gt; beats (Swatch Internet Time) <br /> |-<br /> | Jul 10 || 1,000 ISS orbits <br /> |-<br /> | Jul 11 || 🎵🎶🎵 Five hundred twenty five thousand (base seven) minutes<br /> |-<br /> | Jul 12 || 10&lt;sup&gt;50&lt;/sup&gt; Planck times <br /> |-<br /> | Jul 13 || 4,000 episodes of ''The Office'' (skipping ads) <br /> |-<br /> | Jul 14 || Four score and seven kilominutes <br /> |-<br /> | Jul 15 || 2 lunar months <br /> |-<br /> | Jul 16 || Half a day on Venus <br /> |-<br /> | Jul 17 || 5 megaseconds <br /> |-<br /> | Jul 18 || 30 microLits (1/1,000,000th of the time since the invention of literature) <br /> |-<br /> | Jul 19 || 1,000 viewings of ''Run Lola Run'' <br /> |-<br /> | Jul 20 || One million sound-miles <br /> |-<br /> | Jul 21 || 30 Ionian months <br /> |-<br /> | Jul 22 || One dog year <br /> |-<br /> | Jul 23 || 60 viewings of ''Star Wars Episodes I-IX''<br /> |-<br /> | Jul 24 || 1/100,000,000,000th of the universe's age <br /> |-<br /> | Jul 25 || 5 milli-generations <br /> |-<br /> | Jul 26 || 10,000 games of ''7 minutes in Heaven'' or 7 games of ''10,000 minutes in Heaven'' <br /> |-<br /> | Jul 27 || φ&lt;sup&gt;e&lt;sup&gt;π&lt;/sup&gt;&lt;/sup&gt; minutes <br /> |-<br /> | Jul 28 || 4 megaseconds <br /> |-<br /> | Jul 29 || 2&lt;sup&gt;16&lt;/sup&gt; minutes <br /> |-<br /> | Jul 30 || e&lt;sup&gt;e&lt;sup&gt;e&lt;/sup&gt;&lt;/sup&gt; seconds <br /> |-<br /> | Jul 31 || π fortnights <br /> |-<br /> | Aug 1 || one devil's spacewalk (666 orbits of the ISS) <br /> |-<br /> | Aug 2 || 1 kilowatt-hour per watt <br /> |-<br /> | Aug 3 || e&lt;sup&gt;π&lt;/sup&gt; Ionian months <br /> |-<br /> | Aug 4 || 30 rotations of Foucault's pendulum in Paris <br /> |-<br /> | Aug 5 || e fortnights <br /> |-<br /> | Aug 6 || π&lt;sup&gt;e&lt;/sup&gt; baker's days (25 hours) <br /> |-<br /> | Aug 7 || one deciyear <br /> |-<br /> | Aug 8 || 7! milliweeks <br /> |-<br /> | Aug 9 || 100,000 plays of the ''Jeopardy!'' &quot;Think&quot; music <br /> |-<br /> | Aug 10 || 1000 basketball games (game time) <br /> |-<br /> | Aug 11 || 777 hours <br /> |-<br /> | Aug 12 || one millilincoln (1/1000 of fourscore and seven years) <br /> |-<br /> | Aug 13 || 1,000 episodes of ''60 Minutes'' (skipping ads) <br /> |-<br /> | Aug 14 || All of ''Star Trek'', consecutively<br /> |-<br /> | Aug 15 || 777,777 nanocenturies <br /> |-<br /> | Aug 16 || one sidereal lunar month <br /> |-<br /> | Aug 17 || 6 dog months <br /> |-<br /> | Aug 18 || π&lt;sup&gt;π&lt;/sup&gt; kilominutes <br /> |-<br /> | Aug 19 || 7 games of ''7! minutes in Heaven'' <br /> |-<br /> | Aug 20 || 50 viewings of the extended ''Lord of the Rings'' trilogy <br /> |-<br /> | Aug 21 || A drive from NYC to LA where you keep remembering new things you forgot and have to go back 6 times <br /> |-<br /> | Aug 22 || ''It's a Small World'' sung at 1/10,000th speed <br /> |-<br /> | Aug 23 || 500 hours <br /> |-<br /> | Aug 24 || √2 fortnights <br /> |-<br /> | Aug 25 || Time it would take Vanessa Carlton to walk 1,000 miles <br /> |-<br /> | Aug 26 || 100,000 breaths <br /> |-<br /> | Aug 27 || √2 megaseconds <br /> |-<br /> | Aug 28 || π&lt;sup&gt;π&lt;sup&gt;π&lt;/sup&gt;&lt;/sup&gt; πcoseconds <br /> |-<br /> | Aug 29 || One baker's fortnight (15 days) <br /> |-<br /> | Aug 30 || One baker's dozen (13) baker's days (25 hours) <br /> |-<br /> | Aug 31 || 300 hours <br /> |-<br /> | Sep 1 || One million seconds <br /> |-<br /> | Sep 2 || One nonstop bike ride from NYC to LA <br /> |-<br /> | Sep 3 || &lt;sup&gt;1&lt;/sup&gt;⁄&lt;sub&gt;1,000&lt;/sub&gt;th of a generation <br /> |-<br /> | Sep 4 || 777,777 seconds <br /> |-<br /> | Sep 5 || 100 viewings of ''Groundhog Day'' <br /> |-<br /> | Sep 6 || 100 games of ''Lincoln Kissing'' (Fourscore and seven minutes in Heaven) <br /> |-<br /> | Sep 7 || One pico-universe-lifetime <br /> |-<br /> | Sep 8 || The ''Baby Shark'' chorus for a family of 50,000 sharks <br /> |-<br /> | Sep 9 || One centiyear <br /> |-<br /> | Sep 10 || Cyndi Lauper's ''Time After Time'' played 1,000 times <br /> |-<br /> | Sep 11 || ''Speed'' (1994) played at one frame per second <br /> |-<br /> | Sep 12 || F(99) where F(N) means sing all the verses of ''N Bottles of Beer On the wall'' followed by F(N-1) <br /> |-<br /> | Sep 13 || * ''What If? 2'' release day *<br /> |}<br /> {{comic discussion}}<br /> [[Category:Book promotion]]<br /> [[Category:Comics featuring real people]]<br /> [[Category:Songs]]<br /> [[Category:Animals]]</div>

172.70.211.36 https://www.explainxkcd.com/wiki/index.php?title=2638:_Extended_NFPA_Hazard_Diamond&diff=288094 2022-07-02T22:57:32Z

<p>172.70.211.36: /* Explanation */ completely decomposes in the presence of moisture including solid hydrates. A single &quot;scrubbing&quot; would certainly remove all of it, but replace it with hydrochloric acid</p> <hr /> <div>{{comic<br /> | number = 2638<br /> | date = June 27, 2022<br /> | title = Extended NFPA Hazard Diamond<br /> | image = extended_nfpa_hazard_diamond.png<br /> | titletext = With most labs, the hushed horror stories are about something like dimethylmercury or prions, but occasionally you'll get a weird lab where it's about the soda machine or the drop ceiling.<br /> }}<br /> <br /> ==Explanation==<br /> {{incomplete|Created by a SUBSTANCE WORTH $500 IN STREET VALUE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br /> <br /> This comic depicts an extension of the National Fire Protection Association's {{w|NFPA 704|NFPA 704 Standard System for the Identification of the Hazards of Materials for Emergency Response}} &quot;fire diamond&quot; emblematic insignia used to warn about the properties of hazardous substances inside a building, vehicle, room, cabinet, or container that are important during an emergency or accident, such as a fire, earthquake, spill or leak, bringing the diamond from 2x2 squares to 3x3 by adding five variously useful and humorous squares along the bottom edges.<br /> <br /> The numbers in a normal NFPA 704 diamond do not specify values of substances' properties, but rather broad categories designating characteristics of the substances of greatest interest to {{w|first responders}} and hazardous materials cleanup crews. Randall's expanded diamond breaks with this convention, with several squares (Lilac, Orange, and Black) denoting absolute values, and one square (Green) denoting an economic value. This could very easily lead to documentation update headaches if these values were ever to change, doubly so since the Lilac square is linked to political outcomes.<br /> <br /> {| class=&quot;wikitable&quot;<br /> |+ Squares and explanations<br /> |-<br /> ! Square !! Color !! Comic text !! Explanation<br /> |-<br /> !colspan=5| Real NFPA 704 diamond [http://www.ilpi.com/msds/ref/nfpa.html square and number meanings]<br /> |-<br /> | Top || Red || Flammability (0) || Denotes flammability. 0 indicates &quot;materials that will not burn.&quot;<br /> |-<br /> | Top Left || Blue || Health Hazard (4) || Denotes the danger that the substance(s) pose to living beings in ways other than flammability and reactivity. 4 indicates that &quot;Very short exposure could cause death or serious residual injury even though prompt medical attention was given.&quot;<br /> |-<br /> | Top Right || Yellow || Instability (2) || Denotes how stable the substance(s) are when exposed to water, heat, shock, air, or other substances. 2 indicates that &quot;Normally unstable and will readily undergo violent decomposition but does not detonate. Also: may react violently with water or may form potentially explosive mixtures with water.&quot;<br /> |-<br /> | Center || White || (Special Hazard) || The standard's &quot;Special Notice&quot; field may contain a symbol denoting additional information about the substance(s), e.g., '''OX''' for {{w|oxidizer}}s, '''SA''' for simple {{w|asphyxiant}} gases such as nitrogen and helium, and &lt;s&gt;'''W'''&lt;/s&gt; for substances which react dangerously with water.<br /> |-<br /> !colspan=5| After this point, all squares are made up by Randall.<br /> |-<br /> | Center Left || Green || Number of digits in the street value ($/gram) (2) || Describes the order of magnitude of the price (in USD) of one gram of the substance when sold illegally and informally. This is done on a logarithmic scale, with a '1' selling for $9/gram or less, a '2' selling for $99/gram, and so on. As such this is the first of several squares where the number may presumably go to 5 or above (which is not allowed on the original Blue/Red/Yellow squares, as they do not denote strict numerical values). That said it's not immediately clear how substances which command &lt;$1/gram would be handled.<br /> <br /> Randall's example substance apparently sells for tens of dollars per gram (which would be similar to most common illicit drugs).<br /> |-<br /> | Center Right || Dark Purple || How much of a hassle it is to dispose of (4) || While many things can be thrown in the trash with no additional procedures, substances that merit an NFPA 704 square often require additional procedures to avoid significant danger, damage to the environment, or hefty dumping fines. Biohazards that may carry diseases are often disposed of in special containers, and nuclear materials are notoriously difficult to safely dispose of. This square would be at least theoretically useful, though not as much as the actual disposal guidelines.<br /> <br /> If the numbering here follows the scheme of the real categories, Randall's example substance is about as hard to dispose of as it gets. This matches the substance's rating of 4 for Blue and 2 for Yellow. Presumably it requires highly specialized handling or processing, and may also very bulky or awkward to store.<br /> |-<br /> | Bottom Left || Lilac || Number of federal agencies who want to know if you have any (3) || In many countries, including Randall's home country, the USA, the government has agencies dedicated to controlling or limiting the use of regulated substances, due to their use as drugs, weapons, harm to the environment, etc. While any given substance might be of interest to one agency, something that is both an environmental hazard and a chemical weapon component could interest, for example, the {{w|EPA}}, {{w|Chemical Safety Board}} and the FBI Counter-terrorism Division.<br /> |-<br /> | Bottom Right || Orange || How many times you have to scrub your hands after touching it before they stop smelling weird (1) || While the real NFPA 704 chart describes properties ranging from unsafe to potentially deadly, this square describes a minor but very real inconvenience. Some things are harder to wash off your hands than others, and, given that most people don't often work with dangerous substances {{Citation Needed}}, this would be a more common, but less relevant, concern for many people.<br /> <br /> In this case, the substance, or its residue, seems to be fairly easy to wash off. This is seemingly incongruous with its ratings in the Blue and Black squares (see below), though it's possible that this substance simply doesn't have a strong odor.<br /> |-<br /> | Bottom || Black || Number of times it's caused one of those terrifying lab accidents that chemists tell scary stories about late at night (2) || This square might show how concerned and careful someone should be in handling the substance in question, especially if the number is more than one. However, it would be dependent not just on how inherently dangerous the substance is, but also on how commonly it occurs in labs. It's also vague as to what kind of accidents it has been involved in and what precautions therefore need to be taken. It could, for example, have caused some terrifying reaction, destroying things around it, or it could be very large and unwieldy and liable to crush people if handled improperly.<br /> <br /> In this case, it seems the substance has caused two such accidents, presumably on account of its high health risk of 4 in the Blue square, and may also be linked to its hazardous disposal score of 4 in the Purple square.<br /> |}<br /> <br /> The title text (which references &quot;scary stories&quot; of the Black square) refers to {{w|dimethylmercury}} and {{w|prions}}. Dimethylmercury, C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;Hg, is an organic form of mercury with an NFPA score of 4-4-3 (contact can be fatal, will burn below 73° F (22 °C), will combust if put under pressure). In 1997, an American chemist, {{w|Karen Wetterhahn}}, died 298 days after a few drops of C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;Hg on her latex gloves were absorbed into her hand through the gloves, causing fatal mercury poisoning. Despite her having followed all safety protocols of the time, it was not then understood that the chemical was so toxic, nor that latex was so permeable to it. Prions are misfolded proteins that are responsible for a number of neurodegenerative diseases, including {{w|mad cow disease}} and {{w|chronic wasting disease}} in non-human animals and {{w|Creutzfeldt-Jakob disease}} in humans. These would indeed be the kind of substances that would scare those working with them in their labs; if an accident occurred, the results could be calamitous. See for example the case of [https://arstechnica.com/science/2021/07/second-lab-worker-with-deadly-prion-disease-prompts-research-pause-in-france/ Émilie Jaumain], a lab technician who died after accidentally coming into contact with prions in mouse tissue.<br /> <br /> But a few labs have apparently had accidents involving a soda machine or {{w|dropped ceiling}}. The latter may be a reference to {{w|1978 smallpox outbreak in the United Kingdom|the death of Janet Parker}}: One inquiry found that she was infected with {{w|smallpox}} when a sample traveled upward from a lab on the floor below hers; however, other investigations have challenged that finding. There are occasional instances of vending machines causing injury or death, usually caused by people trying to shake or tilt the machines to get product out and having the machine tip and fall on them. On average, [https://www.cpsc.gov/Newsroom/News-Releases/1996/CPSC-Soda-Vending-Machine-Industry-Labeling-Campaign-Warns-Of-Deaths-And-Injuries a couple of Americans per year] are killed in this way. Reagents obtained in this way tend to have more impurities than those usually used in labs, but are relatively safe to shake.<br /> <br /> The only easily identifiable substance which could likely meet the specific insignia numbers shown in the comic is {{w|thionyl chloride}} (SOCl&lt;sub&gt;2&lt;/sub&gt;), a chlorinating reagent and solvent regulated as a chemical weapons precursor and sometimes used in the production of methamphetamine, which would also be represented with the '''&lt;s&gt;W&lt;/s&gt;''' symbol inside the white square, indicating reactivity with water.<br /> <br /> ==Transcript==<br /> {{incomplete transcript|Do NOT delete this tag too soon.}}<br /> :Know your extended NFPA hazard diamond:<br /> <br /> :[The diamond is divided into 3x3 squares.]<br /> :Flammability: 0 (top, red)<br /> :Health hazard: 4 (top-left, blue)<br /> :Instability/reactivity: 2 (top-right, yellow)<br /> :Number of digits in the street value ($/gram): 2 (left, green)<br /> :(Special hazard) (center, white)<br /> :How much of a hassle it is to dispose of: 4 (right, purple)<br /> :Number of federal agencies who want to know if you have any: 3 (bottom-left, pink)<br /> :How many times you have to scrub your hands after touching it before they stop smelling weird: 1 (bottom-right, orange)<br /> :Number of times it's caused one of those terrifying lab accidents that chemists tell scary stories about late at night: 2 (bottom, black)<br /> <br /> {{comic discussion}}<br /> <br /> [[Category:Science]]<br /> [[Category:Chemistry]]<br /> [[Category:Comics with color]]</div>

172.70.211.36