https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=172.70.210.125&feedformat=atomexplain xkcd - User contributions [en]2024-03-19T05:15:09ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=2671:_Rotation&diff=2948722671: Rotation2022-09-14T21:54:03Z<p>172.70.210.125: /* Explanation */ term</p>
<hr />
<div>{{comic<br />
| number = 2671<br />
| date = September 12, 2022<br />
| title = Rotation<br />
| image = rotation.png<br />
| titletext = It's okay, we can just feed the one-pixel image into an AI upscaler and recover the original image, or at least one that's just as cool.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by an IMAGE UPSCALER. Do NOT delete this tag too soon.}}<br />
<br />
Another of [[Randall]]'s [[:Category:Tips|Tips]], this tip claims that rotating a phone and taking a screenshot too many times will cause an image to disappear into nothingness as it will become smaller than the planck length, and warns the user against doing so. This is absurd because the camera and the display both have limited resolutions. The detail of the original screenshot at the center of the image will be aggregated out as it approaches the range of a few pixels, hence the original image will be lost before it reaches the sub-pixel range. This is funny because the default resolution of contemporary camera phones can be too large to meet size requirements for e.g. mobile phone {{w|Multimedia Messaging Service}}, web file uploads, or email attachments, so one or two steps of this awkward procedure is sometimes necessary.<br />
<br />
[[Image:World lines and world sheet.svg|thumb|200px|{{w|String theory}} describes the {{w|worldline}}s of point-like particles as {{w|worldsheet}}s of "closed strings," forming a topological foam.]]<br />
<br />
For a fuller explanation of the concepts involved, including {{w|Planck units}}, often associated with the topological {{w|quantum foam}} of {{w|string theory}}, please see [https://www.youtube.com/watch?v=pUF5esTscZI this CGP Grey video.] For an explanation of topological string theory, see [[2658: Coffee Cup Holes]]. Please see also [[1683: Digital Data]] for an analogous image processing concept.<br />
<br />
The title text refers to producing photographically likely higher resolution images from lower resolutions, an active area of current research.[https://openaccess.thecvf.com/content/ICCV2021/papers/Liang_Hierarchical_Conditional_Flow_A_Unified_Framework_for_Image_Super-Resolution_and_ICCV_2021_paper.pdf] Because reducing the resolution of an image is a lossy process, results obtained through such processes will not be able to perfectly recreate the original. Machine learning can be used to calculate how images of known photographic subjects (or e.g. anime-style art, in the case of {{w|waifu2x}}) behave under certain types of noise or reduction in size, so that images ''of those kinds'' can be upscaled in a way that, if not perfectly recreating the original, at least is a faithful representation, but when the image is scaled all the way down to one pixel, everything except a small amount of data about the image's overall color is lost, making reconstructing the original image impossible. Randall disclaims that, because the AI upscaling is based on ingesting a large corpus of human-made art (with subjects that we find 'interesting' or at least meaningful being predominantly represented), the AI will produce an image that is at least as cool as the original image was. He could also be making a pun on {{w|color temperature}}, which the upscaler will be able to match to the original image. The "[https://tvtropes.org/pmwiki/pmwiki.php/Main/EnhanceButton enhance button]" for upscaling images is a common trope in movies and television, especially in crime and science fiction stories.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:[A phone in portrait orientation shows an image of Cueball standing. It is then rotated, showing the image smaller with bars in landscape orientation, then the next phone is in portrait showing the entire screen of the previous rotated sideways, shrinking it every time. An arrow points from each phone to the phone with the next smaller image, until the last one. The labels, at the 9th, 25th, and 101st rotation, show the decreasing size of the original image as it goes through successive rotations.]<br />
<br />
:[Labels:]<br />
:9 rotations: original image is smaller than a pixel.<br />
<br />
:25 rotations: original image is smaller than an atom.<br />
<br />
:101 rotations: original image is smaller than the Planck length, at which the concept of distance may break down.<br />
<br />
:[Bottom caption:]<br />
:Phone tip: don't rotate and screenshot an image too many times or it will become lost in the quantum foam of the universe.<br />
<br />
{{comic discussion}}<br />
[[Category:Tips]]<br />
[[Category:Smartphones]]<br />
[[Category:Comics featuring Cueball]]</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2653:_Omnitaur&diff=2916932653: Omnitaur2022-08-02T08:58:08Z<p>172.70.210.125: /* Explanation */</p>
<hr />
<div>{{comic<br />
| number = 2653<br />
| date = August 1, 2022<br />
| title = Omnitaur<br />
| image = omnitaur.png<br />
| titletext = "My parents were both omnitaurs, which is how I got interested in recombination," said the normal human.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by AN OMNITAUR-HUMAN HYBRID - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
Omnitaur is an {{w|anagram}} of {{w|minotaur}}, a mythical creature that was part man, part bull. "{{wiktionary|omni}}" is a prefix that means "all". The word is for instance known from the word {{w|omnivore}}, meaning all eating as compared to {{w|carnivore}} or {{w|herbivore}} (only eating meat or plant respectively). Given the combinations of animals used to create the omnitaur, it could be expected that it was also an omnivore.<br />
<br />
An "omnitaur" would suggest that it would encompass all real and mythical creatures, and appears to be a hybrid or {{w|Chimera (genetics)|genetic chimera}} combined from 11 different creatures: {{w|Fish}}, {{w|lion}}, {{w|snake}}, {{w|shark}} (also a fish), {{w|bull}}, {{w|dragon}} (another mythical creature), {{w|horse}}, {{w|leopard}}, {{w|Sheep|ram}} (male sheep), {{w|human}} and {{w|bird}}.<br />
<br />
In addition to the minotaur, many other potential inspirations can be found in mythology, like the {{w|centaur}}, which has the upper body of a human and the lower body and legs of a horse; the {{w|manticore}}, with a body of a lion and human face; a {{w|griffin}}, with a lion's body and a eagle's head; a {{w|mermaid}}, with a lower-body of a fish and upper body of a human; a {{w|Hippocampus (mythology)|hippocampus}}, with the upper body of a horse and a lower body of a fish; a {{w|qilin}}, with a body that resembles both a horse and a dragon; or the mythological {{w|chimera (mythology)|chimera}}, for which the genetic chimera is named, which has lion, snake, and goat body parts. Ultimately, there are {{w|List of hybrid creatures in folklore|lots of hybrid creatures in mythology}}, so without word from [[Randall]] you're free to make your own conclusions.<br />
<br />
The title text is a comment by a human whose parents were both omnitaurs. It would be strange that such parents would not produce offspring that was still omnitaur. It suggests that this may be the result of {{w|genetic recombination}}, which is the exchange of genetic material between different organisms leading to production of offspring with combinations of traits that differ from those found in either parent. Since we don't understand omnitaur genetics, we can't evaluate whether that is a plausible claim. Since the example depicted seems to be only 1/11 human, the odds of two parents like this getting a fully human offspring would simplistically (assuming that each physical part is the result of an equal genetic contribution, which isn't really how genetics works) appear to be 1/11 x 1/11 = 1/121, if it was simply a matter of the math... Of course if it worked like that, it would be hard to explain how a creature consisting of 11 different animals came into existence in the first place.<br />
<br />
It is interesting that Randall chooses to mention fish and shark, given that sharks are fish, and he for sure knows this. It would have been like saying mammal for the lion part and then horse later... Also funny he includes dragons, since all the other animals are real animals.<br />
<br />
In {{w|C. S. Lewis}}' {{w|The Chronicles of Narnia}}, the {{w|Magical_creatures_in_The_Chronicles_of_Narnia#Centaurs|centaurs}} are depicted eating two meals - a huge roast meal "to satisfy the man stomach" and a meal of grass "to satisfy the horse stomach", making it take quite some time for them to eat every morning. This could further support that the omnitaur is an omnivore. But given that there are still only need for two stomachs, one for grass and one for most other stuff, it may not take longer for the omnitaur to eat than for the Centaur. Although the bird beak may slow down the process quite a bit.<br />
<br />
==Transcript==<br />
:[A creature, the Omnitaur, is shown. It is a four legged animal divided into 11 segments, each segments is from a different animal. An arrow goes to each section from a label, most of the labels are above the animal, but the fourth and seventh segments labels are below the animal. The animal has a fish tail and cat like hind legs. The torso is divided into four segments, the first and last of these with scales, but only the last of these also with sharp scales at the top. The second torso segment is white and smooth, the third also white but with hair both above and below, those above merges with the sharp scales of the fourth torso segment. The front legs are horse like, the lower neck is from an animal with dark spots, the upper neck has rams horns, which goes over in the central part of a human head, with ears and hair (drawn like a real human, not like a xkcd stick figure) and finally the front of the face is a bird with its eyes and a beak shown. The labels are given here in the order of the segment of the animal from the back to the front (disregarding weather the label is written above or below the animal:]<br />
:Fish<br />
:Lion<br />
:Snake<br />
:Shark<br />
:Bull<br />
:Dragon<br />
:Horse<br />
:Leopard<br />
:Ram<br />
:Human<br />
:Bird<br />
<br />
:[Caption below the panel:]<br />
:The Omnitaur<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Animals]]<br />
[[Category:Biology]]</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2648:_Chemicals&diff=2899232648: Chemicals2022-07-22T09:52:54Z<p>172.70.210.125: /* Explanation */ ce</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 ISOMER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
In this comic, [[Megan]] mentions to [[Cueball]] that their company spends a lot on chemicals for which you can find formulas online. She suggests assembling chemicals from atoms "bought in bulk," holding a sheet of paper with the {{w|empirical formula}} C<sub>6</sub>H<sub>5</sub>NO<sub>2</sub>, which designates [https://pubchem.ncbi.nlm.nih.gov/#query=C6H5NO2 hundreds of compounds] including {{w|nitrobenzene}}, {{w|niacin}}, {{w|isonicotinic acid}}, and {{w|picolinic acid}}, followed by their component elements listed with prices. The ambiguity of chemical formulae is one of the jokes in the comic.<br />
<br />
While many expensive chemicals are composed entirely of inexpensive and commonly available elements, "assembling" those elements into specific molecules is rarely as simple as Megan is depicting it, especially considering the complexity and specificity required. That work is the primary purpose of the global chemical industry. In-house {{w|chemical synthesis}} is usually not cost effective, because end users have limited time and are generally unable to leverage the {{w|economies of scale}} inherent in bulk manufacturing by specialist industrial firms.[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2880393/] However, we don't know whether Megan and Cueball work in a laboratory, factory, or some other industrial setting. If they need chemicals in bulk, or only very small quantities, synthesizing them might be cost effective.<br />
<br />
In any case, producing chemicals from their constituent elements or {{w|Precursor (chemistry)|precursor compound}}s is difficult and time-consuming, usually requires expensive equipment, and is often fraught with peril.[https://www.youtube.com/watch?v=5QwW2owNWgc] {{w|Nitrobenzene}}, one of the C<sub>6</sub>H<sub>5</sub>NO<sub>2</sub> compounds, is an excellent example because it is explosive and extremely toxic, and its synthesis is highly exothermic, making it one of the most dangerous syntheses in the chemical industry.[https://www.icheme.org/media/10339/xiii-paper-36.pdf] Such issues answer Cueball's question as to why more places don't manufacture their own compounds from atoms. Usually chemicals are derived from precursor chemicals instead of constituent elements. Megan seems to be envisioning 'assembling' chemicals as a much simpler process without reactivity, energy release, or hazardous intermediate substances. Similar to the makerspace movement, community chemical labs have been cropping up, where people work together to perform chemical synthesis and other chemistry acts by sharing community resources.{{citation needed}} The characters' naivety also gives rise to the humor of the comic, which could also be seen as relating to DIY lifehacks where the immediate cost savings only make sense if their time and learning investment is ignored.<br />
<br />
"Big Molecule" is an [[2130: Industry Nicknames|industry nickname like Big Oil or Big Pharma]], amusing in its own right, and conceivably implying that the chemical industry is conspiring to prevent end users from synthesizing their own compounds.<br />
<br />
The title text refers to the fact that people of past generations often believe that "kids these days" don't do enough work or are spoiled. Randall may have expressed that he dislikes other statements like these in [[2165: Millennials|previous comics]]. It may also refer to the decline of home {{w|chemistry set}}s popular from the late 1700s through the early 1980s that encouraged kids to experiment with basic chemical reactions like generating esters or polymers, or the even older decline in home manufacture of gunpowder as was common in the 1800s. Chemical engineering was more widely practiced during the development of plastics, but far fewer people understand how they are made today. Similarly with automobiles, domesticated crops, and many other technologies that progressed through a period of popular attention but became siloed into industries, corporations, governments, or branches of academia. This is happening now with some software, circuitry, and other technologies, where fewer people know how to build and assemble complex devices and systems. Technology users thus lose their ability to repair machines and modify their tools, having instead to rely on paid services.<br />
<br />
This comic 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 individual molecules] by modifying their bonds.<br />
<br />
==Transcript==<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 />
:[Zoom in on Megan who is holding piece of paper up in one hand. The paper has a large chemical formula at the top. Below is a list of the atoms needed, with amount and a price tag in dollars but with unreadable amount. There is a sum total at the bottom beneath a line.]<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 />
:Paper:<br />
::<big>C<sub>6</sub>H<sub>5</sub>NO<sub>2</sub></big><br />
::Carbon 6 $...<br />
::Hydrogen 5 $...<br />
::Nitrogen 1 $...<br />
::<u>Oxygen 2 $...</u><br />
::Total 14 $...<br />
<br />
:[Cueball is now on the left of Megan as she is walking past him to the right holding her arms outstretched with her palms up.]<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 />
<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Chemistry]]</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2648:_Chemicals&diff=2899222648: Chemicals2022-07-22T09:51:10Z<p>172.70.210.125: /* Explanation */ typo</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 ISOMER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
In this comic, [[Megan]] mentions to [[Cueball]] that their company spends a lot on chemicals for which you can find formulas online. She suggests assembling chemicals from atoms "bought in bulk," holding a sheet of paper with the {{w|empirical formula}} C<sub>6</sub>H<sub>5</sub>NO<sub>2</sub>, which designates [https://pubchem.ncbi.nlm.nih.gov/#query=C6H5NO2 hundreds of compounds] including {{w|nitrobenzene}}, {{w|niacin}}, {{w|isonicotinic acid}}, and {{w|picolinic acid}}, followed by their component elements listed with prices. The ambiguity of chemical formulae is one of the jokes in the comic.<br />
<br />
While many expensive chemicals are composed entirely of inexpensive and commonly available elements, "assembling" those elements into specific molecules is rarely as simple as Megan is depicting it, especially considering the complexity and specificity required. That work is the primary purpose of the global chemical industry. In-house {{w|chemical synthesis}} is usually not cost effective, because end users have limited time and are generally unable to leverage the {{w|economies of scale}} inherent in bulk manufacturing by specialist industrial firms.[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2880393/] However, we don't know whether Megan and Cueball work in a laboratory, factory, or some other industrial setting. If they need chemicals in bulk, or only very small quantities, synthesizing them might be cost effective.<br />
<br />
In any case, producing chemicals from their constituent elements or {{w|Precursor (chemistry)|precursor compound}}s is difficult and time-consuming, usually requires expensive equipment, and is often fraught with peril.[https://www.youtube.com/watch?v=5QwW2owNWgc] {{w|Nitrobenzene}}, one of the C<sub>6</sub>H<sub>5</sub>NO<sub>2</sub> compounds, is an excellent example because it is explosive and extremely toxic, and its synthesis is highly exothermic, making it one of the most dangerous syntheses in the chemical industry.[https://www.icheme.org/media/10339/xiii-paper-36.pdf] Such issues answer Cueball's question as to why more places don't manufacture their own compounds from atoms. Usually chemicals are derived from other chemicals, rather than constituent atoms. Megan seems to be envisioning 'assembling' chemicals as a much simpler process without reactivity, energy release, or hazardous intermediate substances. Similar to the makerspace movement, community chemical labs have been cropping up, where people work together to perform chemical synthesis and other chemistry acts by sharing community resources.{{citation needed}} The characters' naivety also gives rise to the humor of the comic, which could also be seen as relating to DIY lifehacks where the immediate cost savings only make sense if their time and learning investment is ignored.<br />
<br />
"Big Molecule" is an [[2130: Industry Nicknames|industry nickname like Big Oil or Big Pharma]], amusing in its own right, and conceivably implying that the chemical industry is conspiring to prevent end users from synthesizing their own compounds.<br />
<br />
The title text refers to the fact that people of past generations often believe that "kids these days" don't do enough work or are spoiled. Randall may have expressed that he dislikes other statements like these in [[2165: Millennials|previous comics]]. It may also refer to the decline of home {{w|chemistry set}}s popular from the late 1700s through the early 1980s that encouraged kids to experiment with basic chemical reactions like generating esters or polymers, or the even older decline in home manufacture of gunpowder as was common in the 1800s. Chemical engineering was more widely practiced during the development of plastics, but far fewer people understand how they are made today. Similarly with automobiles, domesticated crops, and many other technologies that progressed through a period of popular attention but became siloed into industries, corporations, governments, or branches of academia. This is happening now with some software, circuitry, and other technologies, where fewer people know how to build and assemble complex devices and systems. Technology users thus lose their ability to repair machines and modify their tools, having instead to rely on paid services.<br />
<br />
This comic 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 individual molecules] by modifying their bonds.<br />
<br />
==Transcript==<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 />
:[Zoom in on Megan who is holding piece of paper up in one hand. The paper has a large chemical formula at the top. Below is a list of the atoms needed, with amount and a price tag in dollars but with unreadable amount. There is a sum total at the bottom beneath a line.]<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 />
:Paper:<br />
::<big>C<sub>6</sub>H<sub>5</sub>NO<sub>2</sub></big><br />
::Carbon 6 $...<br />
::Hydrogen 5 $...<br />
::Nitrogen 1 $...<br />
::<u>Oxygen 2 $...</u><br />
::Total 14 $...<br />
<br />
:[Cueball is now on the left of Megan as she is walking past him to the right holding her arms outstretched with her palms up.]<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 />
<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Chemistry]]</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2648:_Chemicals&diff=2899212648: Chemicals2022-07-22T09:50:40Z<p>172.70.210.125: /* Explanation */ if you need 10mg and Sigma Aldrich's smallest bottle is 100g for $500, etc.</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 ISOMER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
In this comic, [[Megan]] mentions to [[Cueball]] that their company spends a lot on chemicals for which you can find formulas online. She suggests assembling chemicals from atoms "bought in bulk," holding a sheet of paper with the {{w|empirical formula}} C<sub>6</sub>H<sub>5</sub>NO<sub>2</sub>, which designates [https://pubchem.ncbi.nlm.nih.gov/#query=C6H5NO2 hundreds of compounds] including {{w|nitrobenzene}}, {{w|niacin}}, {{w|isonicotinic acid}}, and {{w|picolinic acid}}, followed by their component elements listed with prices. The ambiguity of chemical formulae is one of the jokes in the comic.<br />
<br />
While many expensive chemicals are composed entirely of inexpensive and commonly available elements, "assembling" those elements into specific molecules is rarely as simple as Megan is depicting it, especially considering the complexity and specificity required. That work is the primary purpose of the global chemical industry. In-house {{w|chemical synthesis}} is usually not cost effective, because end users have limited time and are generally unable to leverage the {{w|economies of scale}} inherent in bulk manufacturing by specialist industrial firms.[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2880393/] However, we don't know whether Megan and Cueball work in a laboratory, factory, or some other industrial setting. If they need chemicals in bulk, or o ly very small quantities, synthesizing them might be cost effective.<br />
<br />
In any case, producing chemicals from their constituent elements or {{w|Precursor (chemistry)|precursor compound}}s is difficult and time-consuming, usually requires expensive equipment, and is often fraught with peril.[https://www.youtube.com/watch?v=5QwW2owNWgc] {{w|Nitrobenzene}}, one of the C<sub>6</sub>H<sub>5</sub>NO<sub>2</sub> compounds, is an excellent example because it is explosive and extremely toxic, and its synthesis is highly exothermic, making it one of the most dangerous syntheses in the chemical industry.[https://www.icheme.org/media/10339/xiii-paper-36.pdf] Such issues answer Cueball's question as to why more places don't manufacture their own compounds from atoms. Usually chemicals are derived from other chemicals, rather than constituent atoms. Megan seems to be envisioning 'assembling' chemicals as a much simpler process without reactivity, energy release, or hazardous intermediate substances. Similar to the makerspace movement, community chemical labs have been cropping up, where people work together to perform chemical synthesis and other chemistry acts by sharing community resources.{{citation needed}} The characters' naivety also gives rise to the humor of the comic, which could also be seen as relating to DIY lifehacks where the immediate cost savings only make sense if their time and learning investment is ignored.<br />
<br />
"Big Molecule" is an [[2130: Industry Nicknames|industry nickname like Big Oil or Big Pharma]], amusing in its own right, and conceivably implying that the chemical industry is conspiring to prevent end users from synthesizing their own compounds.<br />
<br />
The title text refers to the fact that people of past generations often believe that "kids these days" don't do enough work or are spoiled. Randall may have expressed that he dislikes other statements like these in [[2165: Millennials|previous comics]]. It may also refer to the decline of home {{w|chemistry set}}s popular from the late 1700s through the early 1980s that encouraged kids to experiment with basic chemical reactions like generating esters or polymers, or the even older decline in home manufacture of gunpowder as was common in the 1800s. Chemical engineering was more widely practiced during the development of plastics, but far fewer people understand how they are made today. Similarly with automobiles, domesticated crops, and many other technologies that progressed through a period of popular attention but became siloed into industries, corporations, governments, or branches of academia. This is happening now with some software, circuitry, and other technologies, where fewer people know how to build and assemble complex devices and systems. Technology users thus lose their ability to repair machines and modify their tools, having instead to rely on paid services.<br />
<br />
This comic 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 individual molecules] by modifying their bonds.<br />
<br />
==Transcript==<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 />
:[Zoom in on Megan who is holding piece of paper up in one hand. The paper has a large chemical formula at the top. Below is a list of the atoms needed, with amount and a price tag in dollars but with unreadable amount. There is a sum total at the bottom beneath a line.]<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 />
:Paper:<br />
::<big>C<sub>6</sub>H<sub>5</sub>NO<sub>2</sub></big><br />
::Carbon 6 $...<br />
::Hydrogen 5 $...<br />
::Nitrogen 1 $...<br />
::<u>Oxygen 2 $...</u><br />
::Total 14 $...<br />
<br />
:[Cueball is now on the left of Megan as she is walking past him to the right holding her arms outstretched with her palms up.]<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 />
<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Chemistry]]</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2648:_Chemicals&diff=2896512648: Chemicals2022-07-21T05:07:45Z<p>172.70.210.125: /* 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 ISOMER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
In this comic, [[Megan]] mentions that her company spends a lot on chemicals for which you can find formulas online. She suggests assembling chemicals from atoms "bought in bulk," holding a sheet of paper with the {{w|empirical formula}} C<sub>5</sub>H<sub>6</sub>NO<sub>2</sub> which designates [https://pubchem.ncbi.nlm.nih.gov/#query=C5H6NO2 more than a hundred compounds and ions], including {{w|nitrobenzene}}, {{w|niacin}}, {{w|isonicotinic acid}}, and {{w|picolinic acid}}, followed by their component elements listed with prices. The ambiguity of chemical formulae is one of the jokes in the comic.<br />
<br />
While in-house {{w|chemical synthesis}} is sometimes cost effective, usually it is not, because end users are often unable to leverage the {{w|economies of scale}} inherent in bulk manufacturing by specialist industrial firms.[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2880393/] However, we don't know whether Megan and [[Cueball]] work in a laboratory, factory, or some other industrial setting. In-house chemical syntheses in factories using large volumes often ''are'' cost-effective, as can be laboratory syntheses of very small quantities. <br />
<br />
In any case, producing chemicals from their constituent elements or {{w|Precursor (chemistry)|precursor compound}}s is difficult, time-consuming, requires expensive equipment, and is often fraught with peril.[https://www.youtube.com/watch?v=5QwW2owNWgc] Nitrobenzene, one of the C<sub>5</sub>H<sub>6</sub>NO<sub>2</sub> compounds, is an excellent example because it is explosive, extremely toxic, and its synthesis is highly exothermic, making it one of the most dangerous syntheses in the chemical industry.[https://www.icheme.org/media/10339/xiii-paper-36.pdf] Such issues answer Cueball's question as to why more places don't manufacture their own chemicals. The characters' naivety also gives rise to the humor of the comic, which may also be mocking DIY lifehacks where the cost savings only make sense if their massive time investment is ignored. "Big Molecule" is an [[2130: Industry Nicknames|industry nickname like Big Oil or Big Pharma]], and amusing in its own right.<br />
<br />
The title text refers to the fact that many people believe that "kids these days" don't do enough work or are spoiled. Randall has expressed that he dislikes statements like these in [[2165: Millennials|previous comics]].<br />
<br />
This comic 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 individual molecules] by modifying their bonds.<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<sub>6</sub>H<sub>5</sub>NO<sub>2</sub><br />
:Carbon 6 $[illegible]<br />
:Hydrogen 5 $[illegible]<br />
:Nitrogen 1 $[illegible]<br />
:<u>Oxygen 2 $[illegible]</u><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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2648:_Chemicals&diff=2894422648: Chemicals2022-07-20T20:17:13Z<p>172.70.210.125: /* Explanation */ ce</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 "they can assemble" their chemicals themselves. This would be difficult without some fancy chemistry equipment.{{citation needed}}<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 />
<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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2647:_Capri_Suns&diff=2891322647: Capri Suns2022-07-20T06:14:15Z<p>172.70.210.125: rvv</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] "Come on, at least I didn't make the mistake in the other direction!"<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a SPECIAL OPERATIVE TRYING TO HANDLE 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 begins to realize that his attempt to impersonate a doctor has derailed when the hospital staff notice that 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] arguing that this mitigates the severity of his transgression. The guards 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 maximum $10,000 fine, up to three years in prison, or both.[https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=BPC&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 "saline" (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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2640:_The_Universe_by_Scientific_Field&diff=2891312640: The Universe by Scientific Field2022-07-20T06:13:34Z<p>172.70.210.125: /* Explanation */ misuse of comprise</p>
<hr />
<div>{{comic<br />
| number = 2640<br />
| date = July 1, 2022<br />
| title = The Universe by Scientific Field<br />
| image = the_universe_by_scientific_field.png<br />
| titletext = The math and philosophy people also claim everything, but the astronomers argue that the stuff they study really only comprises a small number of paper surfaces.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by A TINY PROPORTION OF A PIE CHART REPRESENTING THE UNIVERSE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
<br />
{{w|Astronomy}} is the study of outer space and celestial phenomena. This comic makes a joke that most of the "universe" falls under the study of astronomy, which makes sense because it is so vast and large and is not studied directly by other fields of science.<br />
<br />
The volume of the {{w|observable universe}} is 3.566×10<sup>80</sup> cubic meters. The volume of Earth is 1.08321×10<sup>21</sup> cubic meters.<br />
<br />
1.08321×10<sup>21</sup> m<sup>3</sup> &divide; 3.566×10<sup>80</sup> m<sup>3</sup> × 100% ≈ 3×10<sup>-58</sup>%, which is scientific notation for the second of the two percentages, the first being its difference from 100%.<br />
<br />
Thus, the universe is comprised almost entirely of the objects of astronomical study, when measured by volume.<br />
<br />
There are many arguments to be made that this is not the most useful way of measuring the size of scientific fields compared to the universe. If we measure the universe by mass-energy instead, for example, the study of physics becomes non-trivial. Other arguments include:<br />
*Astronomers are only studying the {{w|Observational astronomy|observable phenomena}} (i.e. light, subatomic particles, and gravity) of the rest of the universe, leaving the vast majority of the universe's properties (for instance the geology and biochemistry of an unknown planet in a distant galaxy) entirely unstudied.<br />
*Astronomy is only possible due to understanding of physics, optics, chemistry, mathematics, and geometry, so surely they deserve some credit.<br />
*The interesting parts of the universe are not the empty space.<br />
**They are the matter and energy described by physics and chemistry.<br />
**They are the life experiences of people, which are overwhelmingly terrestrial even for professional astronomers (who often complain about how little time they can allocate to making actual astronomical observations).<br />
*It is disingenuous to claim to be studying more than every other field when astronomy and astrophysics publications amount to only about 0.5% of academic science and engineering output worldwide.[https://ncses.nsf.gov/pubs/nsb20214/table/SPBS-34] Other fields may be studying smaller things, but they are studying them much more thoroughly.<br />
<br />
A counterargument is that astronomy, {{w|cosmology}}, and astrophysics are the only scientific disciplines that study the {{w|Big Bang}} and subsequent {{w|Inflation (cosmology)|inflation}} from which all matter, energy, and space itself arose. The ordinary laws of physics can describe neither of those events.<br />
<br />
The title text says that mathematicians and philosophers claim that what they study also represents everything. But (according to the comic) astronomers counter this by saying that they just study things that are written down, and this comprises just tiny amounts of "paper" on the Earth. This claim by mathematicians also appears in [[435: Purity]]. A conceivable counterargument by philosophers could be that any and all science, including astronomy, is nothing more than a branch of {{w|epistemology}}, the philosophical study of knowledge. Another could be that since philosophy includes theology, it is studying something even larger than the universe (although one could argue back that theology is nothing more than writing fiction.)<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:The Universe by Scientific Field<br />
<br />
:[A pie chart is shown. It is white except for a single black line going from the edge of the circle to the middle.]<br />
:Astronomy [The white space]<br />
:99.9999999999999999999999999999999999999999999999999999999997%<br />
<br />
:Other [The black line]<br />
:0.0000000000000000000000000000000000000000000000000000000003%<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Pie charts]]<br />
[[Category:Science]]<br />
[[Category:Astronomy]]<br />
[[Category:Math]]<br />
[[Category:Philosophy]]</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2640:_The_Universe_by_Scientific_Field&diff=2891292640: The Universe by Scientific Field2022-07-20T06:11:45Z<p>172.70.210.125: /* Explanation */ highly debatable</p>
<hr />
<div>{{comic<br />
| number = 2640<br />
| date = July 1, 2022<br />
| title = The Universe by Scientific Field<br />
| image = the_universe_by_scientific_field.png<br />
| titletext = The math and philosophy people also claim everything, but the astronomers argue that the stuff they study really only comprises a small number of paper surfaces.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by A TINY PROPORTION OF A PIE CHART REPRESENTING THE UNIVERSE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
<br />
{{w|Astronomy}} is the study of outer space and celestial phenomena. This comic makes a joke that most of the "universe" falls under the study of astronomy, which makes sense because it is so vast and large and is not studied directly by other fields of science.<br />
<br />
The volume of the {{w|observable universe}} is 3.566×10<sup>80</sup> cubic meters. The volume of Earth is 1.08321×10<sup>21</sup> cubic meters.<br />
<br />
1.08321×10<sup>21</sup> m<sup>3</sup> &divide; 3.566×10<sup>80</sup> m<sup>3</sup> × 100% ≈ 3×10<sup>-58</sup>%, which is scientific notation for the second of the two percentages, the first being its difference from 100%.<br />
<br />
Thus, the universe is comprised almost entirely of the objects of astronomical study, when measured by volume.<br />
<br />
There are many arguments to be made that this is not the most useful way of measuring the size of scientific fields compared to the universe. If we measure the universe by mass-energy instead, for example, the study of physics becomes non-trivial. Other arguments include:<br />
*Astronomers are only studying the {{w|Observational astronomy|observable phenomena}} (i.e. light, subatomic particles, and gravity) of the rest of the universe, leaving the vast majority of the universe's properties (for instance the geology and biochemistry of an unknown planet in a distant galaxy) entirely unstudied.<br />
*Astronomy is only possible due to understanding of physics, optics, chemistry, mathematics, and geometry, so surely they deserve some credit.<br />
*The interesting parts of the universe are not the empty space.<br />
**They are the matter and energy described by physics and chemistry.<br />
**They are the life experiences of people, which are overwhelmingly terrestrial even for professional astronomers (who often complain about how little time they can allocate to making actual astronomical observations).<br />
*It is disingenuous to claim to be studying more than every other field when astronomy and astrophysics publications comprise only about 0.5% of academic science and engineering output worldwide.[https://ncses.nsf.gov/pubs/nsb20214/table/SPBS-34] Other fields may be studying smaller things, but they are studying them much more thoroughly.<br />
<br />
A counterargument is that astronomy, {{w|cosmology}}, and astrophysics are the only scientific disciplines that study the {{w|Big Bang}} and subsequent {{w|Inflation (cosmology)|inflation}} from which all matter, energy, and space itself arose. The ordinary laws of physics can describe neither of those events.<br />
<br />
The title text says that mathematicians and philosophers claim that what they study also represents everything. But (according to the comic) astronomers counter this by saying that they just study things that are written down, and this comprises just tiny amounts of "paper" on the Earth. This claim by mathematicians also appears in [[435: Purity]]. A conceivable counterargument by philosophers could be that any and all science, including astronomy, is nothing more than a branch of {{w|epistemology}}, the philosophical study of knowledge. Another could be that since philosophy includes theology, it is studying something even larger than the universe (although one could argue back that theology is nothing more than writing fiction.)<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:The Universe by Scientific Field<br />
<br />
:[A pie chart is shown. It is white except for a single black line going from the edge of the circle to the middle.]<br />
:Astronomy [The white space]<br />
:99.9999999999999999999999999999999999999999999999999999999997%<br />
<br />
:Other [The black line]<br />
:0.0000000000000000000000000000000000000000000000000000000003%<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Pie charts]]<br />
[[Category:Science]]<br />
[[Category:Astronomy]]<br />
[[Category:Math]]<br />
[[Category:Philosophy]]</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2640:_The_Universe_by_Scientific_Field&diff=2891282640: The Universe by Scientific Field2022-07-20T06:10:21Z<p>172.70.210.125: /* Explanation */ sub-bulleting</p>
<hr />
<div>{{comic<br />
| number = 2640<br />
| date = July 1, 2022<br />
| title = The Universe by Scientific Field<br />
| image = the_universe_by_scientific_field.png<br />
| titletext = The math and philosophy people also claim everything, but the astronomers argue that the stuff they study really only comprises a small number of paper surfaces.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by A TINY PROPORTION OF A PIE CHART REPRESENTING THE UNIVERSE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
<br />
{{w|Astronomy}} is the study of outer space and celestial phenomena. This comic makes a joke that most of the "universe" falls under the study of astronomy, which makes sense because it is so vast and large and is not studied directly by other fields of science.<br />
<br />
The volume of the {{w|observable universe}} is 3.566×10<sup>80</sup> cubic meters. The volume of Earth is 1.08321×10<sup>21</sup> cubic meters.<br />
<br />
1.08321×10<sup>21</sup> m<sup>3</sup> &divide; 3.566×10<sup>80</sup> m<sup>3</sup> × 100% ≈ 3×10<sup>-58</sup>%, which is scientific notation for the second of the two percentages, the first being its difference from 100%.<br />
<br />
Thus, the universe is comprised almost entirely of the objects of astronomical study, when measured by volume.<br />
<br />
There are many arguments to be made that this is not the most useful way of measuring the size of scientific fields compared to the universe. If we measure the universe by mass-energy instead, for example, the study of physics becomes non-trivial. Other arguments include:<br />
*Astronomers are only studying the {{w|Observational astronomy|observable phenomena}} (i.e. light, subatomic particles, and gravity) of the rest of the universe, leaving the vast majority of the universe's properties (for instance the geology and biochemistry of an unknown planet in a distant galaxy) entirely unstudied. By this reasoning, the pie chart would properly have a sliver for astronomy, a sliver for every other field, and the vast majority would not belong to any field.<br />
*Astronomy is only possible due to understanding of physics, optics, chemistry, mathematics, and geometry, so surely they deserve some credit.<br />
*The interesting parts of the universe are not the empty space.<br />
**They are the matter and energy described by physics and chemistry.<br />
**They are the life experiences of people, which are overwhelmingly terrestrial even for professional astronomers (who often complain about how little time they can allocate to making actual astronomical observations).<br />
*It is disingenuous to claim to be studying more than every other field when astronomy and astrophysics publications comprise only about 0.5% of academic science and engineering output worldwide.[https://ncses.nsf.gov/pubs/nsb20214/table/SPBS-34] Other fields may be studying smaller things, but they are studying them much more thoroughly.<br />
<br />
A counterargument is that astronomy, {{w|cosmology}}, and astrophysics are the only scientific disciplines that study the {{w|Big Bang}} and subsequent {{w|Inflation (cosmology)|inflation}} from which all matter, energy, and space itself arose. The ordinary laws of physics can describe neither of those events.<br />
<br />
The title text says that mathematicians and philosophers claim that what they study also represents everything. But (according to the comic) astronomers counter this by saying that they just study things that are written down, and this comprises just tiny amounts of "paper" on the Earth. This claim by mathematicians also appears in [[435: Purity]]. A conceivable counterargument by philosophers could be that any and all science, including astronomy, is nothing more than a branch of {{w|epistemology}}, the philosophical study of knowledge. Another could be that since philosophy includes theology, it is studying something even larger than the universe (although one could argue back that theology is nothing more than writing fiction.)<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:The Universe by Scientific Field<br />
<br />
:[A pie chart is shown. It is white except for a single black line going from the edge of the circle to the middle.]<br />
:Astronomy [The white space]<br />
:99.9999999999999999999999999999999999999999999999999999999997%<br />
<br />
:Other [The black line]<br />
:0.0000000000000000000000000000000000000000000000000000000003%<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Pie charts]]<br />
[[Category:Science]]<br />
[[Category:Astronomy]]<br />
[[Category:Math]]<br />
[[Category:Philosophy]]</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2647:_Capri_Suns&diff=2890732647: Capri Suns2022-07-19T12:16:34Z<p>172.70.210.125: /* Explanation */ link directly to photo</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] "Come on, at least I didn't make the mistake in the other direction!"<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 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}} (IV) drip connection about the same size as such straws, and usually contain a 0.9% sodium chloride (table salt) solution in sterile water so as to be {{w|Tonicity#Isotonicity|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] so it tastes sweet instead of salty like saline.<br />
<br />
The comic implies that a medical doctor would be very unlikely to accidentally mistake saline bags for Capri Sun. Cueball's apparent 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 is pointing out that mistakenly drinking saline out of the bag is better than putting Capri Sun into patient's IV drip, 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 "saline". 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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2647:_Capri_Suns&diff=2890722647: Capri Suns2022-07-19T12:12:35Z<p>172.70.210.125: /* Explanation */ spelling</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] "Come on, at least I didn't make the mistake in the other direction!"<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 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}} (IV) drip connection about the same size as such straws, and usually contain a 0.9% sodium chloride (table salt) solution in sterile water so as to be {{w|Tonicity#Isotonicity|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] so it tastes sweet instead of salty like saline.<br />
<br />
The comic implies that a medical doctor would be very unlikely to accidentally mistake saline bags for Capri Sun. Cueball's apparent 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 is pointing out that mistakenly drinking saline out of the bag is better than putting Capri Sun into patient's IV drip, 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 "saline". 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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2647:_Capri_Suns&diff=2890692647: Capri Suns2022-07-19T12:00:40Z<p>172.70.210.125: /* Explanation */ fix anchor</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] "Come on, at least I didn't make the mistake in the other direction!"<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 about the same size as such straws, and usually contain a 0.9% sodium chloride (table salt) solution in sterile water so as to be {{w|Tonicity#Isotonicity|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] so it 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, 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 "saline". 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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2647:_Capri_Suns&diff=2890682647: Capri Suns2022-07-19T11:58:48Z<p>172.70.210.125: /* Explanation */ trim</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] "Come on, at least I didn't make the mistake in the other direction!"<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 about the same size as such straws, and usually contain a 0.9% sodium chloride (table salt) solution in sterile water so as to be {{w|Tonicity#Isotonicity|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 it 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, 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 "saline". 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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2647:_Capri_Suns&diff=2890672647: Capri Suns2022-07-19T11:57:35Z<p>172.70.210.125: /* 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] "Come on, at least I didn't make the mistake in the other direction!"<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 about the same size as such straws, and usually contain a 0.9% sodium chloride (table salt) solution in sterile water so as to be {{w|Tonicity#Isotonicity|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 it 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 "saline". 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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2647:_Capri_Suns&diff=2890662647: Capri Suns2022-07-19T11:55:46Z<p>172.70.210.125: /* Explanation */ fix link</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] "Come on, at least I didn't make the mistake in the other direction!"<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|Tonicity#Isotonicity|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 "saline". 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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2646:_Minkowski_Space&diff=2889262646: Minkowski Space2022-07-16T08:56:23Z<p>172.70.210.125: /* Apparent distance */ delete section: despite the lack of commas delineating clauses, there's no interpretation which is correct and explanatory. Distance from an observer isn't pertinent, only their relative inertial frames</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 help 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 the 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 frame of reference refers to distances changing when measured in different {{w|inertial frame of reference|inertial frames of reference}}, a concept called the {{w|relativity of simultaneity}}. Here are [https://www.youtube.com/watch?v=asW78vToNLQ some videos] intended [https://www.youtube.com/watch?v=Xrqj88zQZJg to explain] that concept.<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 relate to the {{w|uncertainty principle}}, as quantum states can be represented as vectors in a Hilbert space.<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}}<br />
[[Category:Math]]<br />
[[Category:Physics]]</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2645:_The_Best_Camera&diff=2889232645: The Best Camera2022-07-16T07:46:38Z<p>172.70.210.125: Reword</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 HOLOGRAPHIC 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 [[1235|have them when interesting subjects appear]]. This advice is often given to novice photographers; sometimes phrased as, "The best camera is the one you use most." 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, "the best camera" 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 by space telescopes, although {{w|HD1 (galaxy)|further objects}} have been identified by terrestrial telescopes. The telescope has [https://www.stsci.edu/jwst/instrumentation three instruments that can act as "cameras" 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&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&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<sub>2</sub>). 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 five locations will remain 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<sub>2</sub> point of the Earth-Sun system with a period of about 6 months, [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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2646:_Minkowski_Space&diff=2888742646: Minkowski Space2022-07-16T02:36:13Z<p>172.70.210.125: /* Explanation */ Started explanation</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 THE ENEMY SHIP - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<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 Minkowski space, where space-time distance does not depend on which frame of reference is used as long as it is inertial. The fact that whether it is decreasing apparently depends on the frame of reference would be a pun, but it could also be interpreted to mean that the spaceships are accelerating, so their frames of reference are not inertial.<br />
<br />
The title text mentions that hiding in Hilbert space is much easier. This is because Hilbert spaces can be much more complicated than Minkowski space.<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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2646:_Minkowski_Space&diff=2888712646: Minkowski Space2022-07-16T02:09:36Z<p>172.70.210.125: </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 THE ENEMY SHIP - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
{{comic discussion}}</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2645:_The_Best_Camera&diff=2887602645: The Best Camera2022-07-14T06:11:26Z<p>172.70.210.125: /* Explanation */ helpful explainer</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 "The best camera is the one you use most." 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 "the best camera" 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 "cameras" for imaging,] a fourth {{w|optical spectrometer|spectrometer}}-only instrument, and 41 {{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&t=449s other color schemes] when using a subset of the filters' range or 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<sub>2</sub>). The Lagrange Points are a set of five locations which are solutions to 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 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<sub>2</sub> 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] 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 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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2644:_fMRI_Billboard&diff=2886622644: fMRI Billboard2022-07-12T08:26:57Z<p>172.70.210.125: /* Explanation */ explain rest of joke</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 imagining 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; also because academic department rivalries do not usually lead to sabotage, and in the rare cases that they do, it's invariably clandestine instead of so absurdly blatant.<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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2643:_Cosmologist_Gift&diff=2885662643: Cosmologist Gift2022-07-10T23:55:25Z<p>172.70.210.125: /* Explanation */ "entirely composed" means "comprised", and ubiquity is a better description than pervasiveness</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 "gift" 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 "freshly produced" {{w|solar neutrino}}s at Earth is around 7&times;10<sup>10</sup>/cm<sup>2</sup>/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, the mass of about 200 carbon-12 atoms or around 20 to 23 {{w|amino acid}}s. 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, 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 comprised entirely of ubiquitous subatomic particles. A billion neutrinos have a mass of only about 2×10<sup>-12</sup> zeptograms, at about 0.1 {{w|electron volt}}s each.<br />
<br />
The "local source" mentioned in the title text is a joke about the commercial value of fresh, locally produced items, but the comic means the Sun. It takes solar neutrinos slightly more than 8 minutes to reach Earth once they're emitted, roughly the same time as photons take to make the trip. (This doesn't include the time -- [https://en.wikipedia.org/wiki/Radiative_zone approximately 170,000 years] over many [https://news.stanford.edu/pr/97/971219neutrino.html 28 day neutrino cycles] -- that energy takes to get from the core to where photons are emitted at the Sun's surface.) 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 />
:<small>Freshly produced</small><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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2643:_Cosmologist_Gift&diff=2885472643: Cosmologist Gift2022-07-10T00:49:08Z<p>172.70.210.125: /* 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 "gift" 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 "freshly produced" {{w|solar neutrino}}s at Earth is around 7&times;10<sup>10</sup>/cm<sup>2</sup>/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<sup>-12</sup> zeptograms, at about 0.1 {{w|electron volt}}s each.<br />
<br />
The "local source" mentioned in the title text is a joke about the commercial value of fresh, locally produced items, but the comic means the Sun. It takes solar neutrinos less 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 />
:<small>Freshly produced</small><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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2643:_Cosmologist_Gift&diff=2885462643: Cosmologist Gift2022-07-10T00:48:22Z<p>172.70.210.125: /* Explanation */ not a pun</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 "gift" 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 "freshly produced" {{w|solar neutrino}}s at Earth is around 7&times;10<sup>10</sup>/cm<sup>2</sup>/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<sup>-12</sup> zeptograms, at about 0.1 {{w|electron volt}}s each.<br />
<br />
The "local source" mentioned in the title text is a joke about 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 />
:<small>Freshly produced</small><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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=Talk:2643:_Cosmologist_Gift&diff=288494Talk:2643: Cosmologist Gift2022-07-09T01:18:31Z<p>172.70.210.125: Reply</p>
<hr />
<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><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)</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2643:_Cosmologist_Gift&diff=2884852643: Cosmologist Gift2022-07-09T00:30:57Z<p>172.70.210.125: /* Explanation */ copyedit</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 8 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 "freshly produced" {{w|solar neutrino}}s at Earth is around 7&times;10<sup>10</sup>/cm<sup>2</sup>/s, yielding about 23,000 per cubic meter. <br />
<br />
Four zeptograms is a minuscule mass, equal to eight sextillionths of a gram, the mass of about 400 carbon-12 atoms. Some cosmologists believe that dark matter is comprised entirely of black holes,[https://news.yale.edu/2021/12/16/black-holes-and-dark-matter-are-they-one-and-same] not omnipresent subatomic particles, in which case there is actually no dark matter at all in the box.<br />
<br />
The "local source" 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]<br />
<br />
:Box:<br />
:30,000 neutrinos<br />
:Freshly produced<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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2643:_Cosmologist_Gift&diff=2884832643: Cosmologist Gift2022-07-09T00:28:25Z<p>172.70.210.125: /* Explanation */ copyedit</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 8 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. <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 "freshly produced" {{w|solar neutrino}}s at Earth is around 7&times;10<sup>10</sup>/cm<sup>2</sup>/s, yielding about 23,000 per cubic meter. <br />
<br />
Eight zeptograms is a minuscule mass, equal to eight sextillionths of a gram, the mass of about 400 carbon-12 atoms. Some cosmologists believe that dark matter is comprised entirely of black holes,[https://news.yale.edu/2021/12/16/black-holes-and-dark-matter-are-they-one-and-same] not omnipresent subatomic particles, in which case there is actually no dark matter at all in the box.<br />
<br />
Wwhile Randall suggests that the neutrinos and dark matter in an empty box would make a good gift for a cosmologist, what they would do with a box of fresh neutrinos and dark matter is uncertain.<br />
<br />
The "local source" 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]<br />
<br />
:Box:<br />
:30,000 neutrinos<br />
:Freshly produced<br />
:Plus 4 zetograms 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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=Talk:2642:_Meta-Alternating_Current&diff=288450Talk:2642: Meta-Alternating Current2022-07-08T16:39:10Z<p>172.70.210.125: </p>
<hr />
<div>And today, we are reminded that [[Randall]] used to be a physicist (or at least has a physics degree). Not worth mentioning in the article, but while inverters can't reverse each other, transformers can. (Has Randall done the transformer/Transformer pun yet as an excuse to mock the movies?) [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 11:10, 7 July 2022 (UTC)<br />
: I haven't picked up the physics reference yet. I see electrical engineering here. Randall strikes me as somebody who would study physics given the opportunit, though. It's notable that this webcomic started while Randall was in college, if I recall right. [[Special:Contributions/172.70.230.75|172.70.230.75]] 11:58, 7 July 2022 (UTC)<br />
<br />
Long distance links, especially those between separate unsynchronized grids, use high voltage DC. There is a 2,000-mile link in China running at 1 MV. [[User:Arachrah|Arachrah]] ([[User talk:Arachrah|talk]]) 11:32, 7 July 2022 (UTC)<br />
:That's because at great distances, relatively high frequency AC loses a lot of ("active" = actually useful) power as ... reactive power, I think (didn't learn the terminology in English, unit seems right though). A typical grid has a lot of generators and load. A long distance connection results in a phase shift according to the transmission time (speed of light in medium x distance) in about the order of magnitude of the AC period (usually somewhere between 1/10 to 1/60 seconds) wastes a portion equal to the sine of the phase shift angle (up to 90° = all of it) as reactive power. DC isn't quite as easy to use but on long distances there is no power loss to reactive power. [[User:627235|627235]] ([[User talk:627235|talk]]) 12:25, 7 July 2022 (UTC)<br />
<br />
Let's face it, the thing should be called an alternator. Of course that name's taken as a redundant word for (electrical) generator. [[User:627235|627235]] ([[User talk:627235|talk]]) 12:26, 7 July 2022 (UTC)<br />
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It always bothered me that UPS battery backups take the wall AC and convert it to DC to charge the battery, but then have to turn it back to AC to send it to the computer, so the power supply can convert it to DC to run the thing. I picture some connector that goes directly from the UPS to the power supply so that if power is lost it can just pull 12V directly from the battery. [[User:Andyd273|Andyd273]] ([[User talk:Andyd273|talk]]) 12:47, 7 July 2022 (UTC)<br />
:some UPSs do this. They normally power the computer directly from the input AC, but if there is a power failure, they use the battery to power the inverters and switch the output to the inverter. Other UPSs always power the computer from the inverter. They have the advantage that there is not even a milisecond time to start powering the computer. That can be better for some equipment, and that kind of UPS often costs more. It is also worth noting that in some data centers, they bypass the AC step and have one big DC power supply that directly powers the computers. [[User:WhiteDragon|WhiteDragon]] ([[User talk:WhiteDragon|talk]]) 16:49, 7 July 2022 (UTC)<br />
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[https://en.wikipedia.org/wiki/Inverter_(logic_gate) NOT logic gates] are also often known as inverters. An even number of those '''would''' indeed produce the same output as the (true/false) input. [[Special:Contributions/108.162.242.58|108.162.242.58]] 16:03, 7 July 2022 (UTC)<br />
<br />
“Further chaining this into more inverters/rectifiers would normally not be considered.”<br />
Well, if you take a DCC controlled model railway for camping, you get a second stage of inverter/rectifier.<br />
The power supply of the DCC control station usually expects AC input, so you invert the DC of the car battery.<br />
The PSU then makes DC for the control station processor, which is then made AC to generate a DCC signal.<br />
The locomotives always have a rectifier to get a DC power supply from the DCC signal (which is confusingly AC).<br />
<br />
You get a third stage with another plausible trick: put the battery on a car battery charger, which converts AC from the camping site power grid to DC. Then use a locomotive with a (rarely used) BLDC motor, which confusingly needs an inverter generating AC.<br />
--[[Special:Contributions/172.71.94.181|172.71.94.181]] 18:01, 7 July 2022 (UTC)<br />
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The efficiency calculation is bogus. For the rectifier, the "efficiency" of 81% relates to voltage, not power. (See https://en.wikipedia.org/wiki/Rectifier). I don't know what the power efficiency is, but I do note that my computer's power supply is not glowing white hot.<br />
:Where do you propose the extra current to make up for such difference would come from? [[Special:Contributions/172.70.206.213|172.70.206.213]] 21:38, 7 July 2022 (UTC)<br />
::When you convert AC to DC or DC to AC, you can't qualify either with single number for voltage OR current. You need to examine whole graph, because both voltage and current are changing with frequency of (original) AC. I'm pretty sure that 81% figure is related to the different way how voltage is computed for AC and DC. That said, regarding the gloving power supply ... usually, power supply contains fan, and while it's partially used to cool the case interior, the power supply might not like it being stopped either. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 22:24, 7 July 2022 (UTC)<br />
:Your computer's power supply has switching H-bridge MOSFET transistors that sense and match the AC phase, not an ordinary diode rectifier. [[Special:Contributions/172.70.206.213|172.70.206.213]] 23:25, 7 July 2022 (UTC)<br />
I interpreted Randall imagining "inversion" as "reciprocal" (or maybe the inversion of a function) rather than physically turning something upside-down, since mathematical inversion is typically reversible... [[Special:Contributions/172.70.130.121|172.70.130.121]] 03:48, 8 July 2022 (UTC)<br />
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Should the description also comment on the choice of number for this "connector". Obviously related to the fact that wall outlet voltage in the US is frequently (pun intended) 120 Volts. [[User:MAP|MAP]] ([[User talk:MAP|talk]]) 14:41, 8 July 2022 (UTC)<br />
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Two inverters *can* cancel each other out if they are the simplest type (a commutator, a.k.a. square wave inverter) *and* they happen to be synchronous. Expect glitches at the commutation points though! [[Special:Contributions/172.70.210.125|172.70.210.125]] 16:39, 8 July 2022 (UTC)</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=No_One_Was_Hurt&diff=288354No One Was Hurt2022-07-07T02:56:35Z<p>172.70.210.125: /* Explanation */ spelling</p>
<hr />
<div>{{comic<br />
| number = 2642<br />
| date = July 6, 2022<br />
| title = No One Was Hurt<br />
| image = no_one_was_hurt.png<br />
| titletext = See how the smoke obscures things so you don't see the approaching tornado until the firework streamers start to swirl right before the lightning hits the launcher. Thank God Cousin Ed was filming in slow motion. And, uh, that no one was hurt.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a BOX OF FIREWORKS UNDER THE CAR - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
[[Ponytail]] is about to show [[Cueball]] and [[Megan]] a video of a dramatic accident from a {{w|4th of July}} celebration with {{w|fireworks}}, in which nobody ended up harmed. Randall suggests that being told nobody got hurt implies such a video will be particularly interesting or exciting.<br />
<br />
The title text describes a particularly dramatic fireworks show interrupted by a tornado and thunderstorm, the joke being that the speaker was more appreciative of there being a slow-motion video recording than that nobody was harmed.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
[Ponytail is showing her phone to Cueball and Megan.]<br />
<br />
Ponytail: Okay, first of all, no one was hurt...<br />
<br />
Caption: How you know you're about to see a really good 4th of July video<br />
<br />
{{comic discussion}}</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=No_One_Was_Hurt&diff=288353No One Was Hurt2022-07-07T02:54:29Z<p>172.70.210.125: /* Explanation */ explain</p>
<hr />
<div>{{comic<br />
| number = 2642<br />
| date = July 6, 2022<br />
| title = No One Was Hurt<br />
| image = no_one_was_hurt.png<br />
| titletext = See how the smoke obscures things so you don't see the approaching tornado until the firework streamers start to swirl right before the lightning hits the launcher. Thank God Cousin Ed was filming in slow motion. And, uh, that no one was hurt.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a BOX OF FIREWORKS UNDER THE CAR - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
[[Ponytail]] is about to show [[Cueball]] and [[Megan]] a video of a dramatic accident from a {{w|4th of July}} celebration with {{w|fireworks}}, in which nobody ended up harmed. Randall suggests that being told nobody got hurt implies such a video will be particularly interesting or exciting.<br />
<br />
The title text describes a particularly dramatic fireworks show interrupted by a tornado and thunderstorm, the joke being that the speaker was more appreciative of their being a slow-motion video recording than that nobody was harmed.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
[Ponytail is showing her phone to Cueball and Megan.]<br />
<br />
Ponytail: Okay, first of all, no one was hurt...<br />
<br />
Caption: How you know you're about to see a really good 4th of July video<br />
<br />
{{comic discussion}}</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=No_One_Was_Hurt&diff=288352No One Was Hurt2022-07-07T02:52:57Z<p>172.70.210.125: /* Explanation */ explain joke</p>
<hr />
<div>{{comic<br />
| number = 2642<br />
| date = July 6, 2022<br />
| title = No One Was Hurt<br />
| image = no_one_was_hurt.png<br />
| titletext = See how the smoke obscures things so you don't see the approaching tornado until the firework streamers start to swirl right before the lightning hits the launcher. Thank God Cousin Ed was filming in slow motion. And, uh, that no one was hurt.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a BOX OF FIREWORKS UNDER THE CAR - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
[[Ponytail]] is about to show [[Cueball]] and [[Megan]] a video of a dramatic accident from a {{w|4th of July}} celebration with {{w|fireworks}}, in which nobody ended up harmed.<br />
<br />
The title text describes a particularly dramatic fireworks show interrupted by a tornado and thunderstorm, the joke being that the speaker was more appreciative of their being a slow-motion video recording than that nobody was harmed.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
[Ponytail is showing her phone to Cueball and Megan.]<br />
<br />
Ponytail: Okay, first of all, no one was hurt...<br />
<br />
Caption: How you know you're about to see a really good 4th of July video<br />
<br />
{{comic discussion}}</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=No_One_Was_Hurt&diff=288351No One Was Hurt2022-07-07T02:50:14Z<p>172.70.210.125: /* Explanation */ title text</p>
<hr />
<div>{{comic<br />
| number = 2642<br />
| date = July 6, 2022<br />
| title = No One Was Hurt<br />
| image = no_one_was_hurt.png<br />
| titletext = See how the smoke obscures things so you don't see the approaching tornado until the firework streamers start to swirl right before the lightning hits the launcher. Thank God Cousin Ed was filming in slow motion. And, uh, that no one was hurt.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a BOX OF FIREWORKS UNDER THE CAR - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
<br />
[[Ponytail]] is about to show [[Cueball]] and [[Megan]] a video of a dramatic accident from a {{w|4th of July}} celebration with {{w|fireworks}}, in which nobody ended up harmed.<br />
<br />
The title text describes a particularly dramatic fireworks show interrupted by a tornado and thunderstorm.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
[Ponytail is showing her phone to Cueball and Megan.]<br />
<br />
Ponytail: Okay, first of all, no one was hurt...<br />
<br />
Caption: How you know you're about to see a really good 4th of July video<br />
<br />
{{comic discussion}}</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=Talk:2641:_Mouse_Turbines&diff=288350Talk:2641: Mouse Turbines2022-07-07T02:47:49Z<p>172.70.210.125: reply</p>
<hr />
<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><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 "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)."<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 />
: I'm not sure how you'd judge that it's twice the size of a fist, given that stick people don't really have fists. I would assume that they're meant to be about the same size as dandelion heads - so about 3 or 4 cm (unless US dandelions are bigger than UK ones). They certainly look about that size in the second panel. You'd also need to factor in problems of interference, given the 'planting density' of these turbines, and the sub-optimal location surrounded by grasses, etc. [[Special:Contributions/172.70.86.44|172.70.86.44]] 08:08, 6 July 2022 (UTC)<br />
::The rotating diameter is shown as about a third the height of Beret Guy's head, so it's definitely not 20 cm. [[Special:Contributions/172.70.210.125|172.70.210.125]] 02:47, 7 July 2022 (UTC)<br />
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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 />
::Mice consume a lot more food per body weight (especially for body heat because heat transfer scales with surface area, not mass/volume) than humans. Mouse-sized fridge efficiency would also be poor both because of the same size issue and reduced room for insulation. [[User:627235|627235]] ([[User talk:627235|talk]]) 11:13, 5 July 2022 (UTC)<br />
::A 480 ml insulin travel fridge uses 5 watts on a 3% duty cycle depending on the ambient temperature and how much it's loaded, so that's in the realm of possibility, and seems large enough. I used to feed lab mice about 5 grams of Purina Lab Rodent Chow daily, which was maybe 8ml volume, but it doesn't need to be refrigerated. Googling suggests field mice can get all the water they need from a diet of seeds. It seems to me that if mice could use electricity, they'd need it more in the winter than the summer. [[Special:Contributions/172.70.211.52|172.70.211.52]] 22:01, 5 July 2022 (UTC)<br />
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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 />
:Not sure about numbers but some (if not most) energy requirements scale by surface area ({{w|Square–cube law}} or other measurements. There are also efficiency issues with at least lots of human-made miniature machines. [[User:627235|627235]] ([[User talk:627235|talk]]) 11:13, 5 July 2022 (UTC)<br />
::What energy requirements scale by surface area? Pumping water, cooking, and refrigerating scales by mass. Converting footcandles to lumens depends on area, but that doesn't account for much lower mouse ceilings. [[Special:Contributions/172.69.34.6|172.69.34.6]] 22:27, 5 July 2022 (UTC)<br />
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I'm confused by the statement that smaller turbines are less "efficient". 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 "relative power output" 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 "as small as a button cell"] 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 />
::Batteries based on radioactive decay (such as RTGs, thermionic cells, betavoltaic cells) are not nuclear power plants. That term specifically refers to power plants based on nuclear fission reactors. [[User:Zmatt|Zmatt]] ([[User talk:Zmatt|talk]]) 11:38, 6 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 />
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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)<br />
::Turbine efficiency (especially for very small turbines) mostly depends on pressure differential and mass throughput. Water has three orders of magnitude higher density than air. Also, even with just a meter of water column, water offers a 10 kPa pressure differential while you only rarely get that much of a pressure differential in air (at the same height) even between areas of high and low pressure usually at least dozens (and commonly hundreds) of miles apart (there may be exceptions for things like tornadoes but good luck using their wind power), certainly not between the high and low pressure sides of a turbine. Efficiency in practice mostly depends on moved mass (of turbine blades, etc) compared to moved medium (water or air), friction (mount, generator, maybe a gearbox) compared to total power input and (if electricity is desired) generator efficiency which itself depends on generator size and rotation speed (hence the need for a gearbox). For a very small turbine, all those things would need to be extremely light as well. [[User:627235|627235]] ([[User talk:627235|talk]]) 11:13, 5 July 2022 (UTC)<br />
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Who is Beret Guy telling to make a wish - Megan or the mice? -- [[User:Ken g6|Ken g6]] ([[User talk:Ken g6|talk]]) 04:48, 5 July 2022 (UTC)<br />
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[https://www.cornel1801.com/animated/Secret-of-NIMH-1982/pictures/64.jpg I must tell you about NIMH.] - [[Special:Contributions/172.70.254.81|172.70.254.81]] 16:13, 5 July 2022 (UTC)<br />
<br />
Sometimes the explanation is funnier than the comic. [[Special:Contributions/172.68.133.159|172.68.133.159]] 03:28, 6 July 2022 (UTC)<br />
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Uh, what happened to the image!? Does anyone know how to fix it? [[Special:Contributions/172.70.110.65|172.70.110.65]] 20:22, 6 July 2022 (UTC)</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=Talk:No_One_Was_Hurt&diff=288349Talk:No One Was Hurt2022-07-07T02:45:02Z<p>172.70.210.125: reply</p>
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<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
<br />
I suppose we should look through e.g. [https://www.reddit.com/r/Fireworksgonewrong r/Fireworksgonewrong] for a few big ones that claim nobody was hurt. [https://www.youtube.com/watch?v=ndVhgq1yHdA] is okay, but I think that one where the launcher tipped over and fired directly into the crowd only resulted in minor burns.... [[Special:Contributions/172.70.207.8|172.70.207.8]] 02:34, 7 July 2022 (UTC)<br />
:If you mean Simi Valley 2013, that had 28 injuries including broken bones(!) Here's one sort of like it without any injuries from Monday, but the video isn't too impressive: [https://www.youtube.com/watch?v=MDhj-dfJ6TE]. [[Special:Contributions/172.70.210.125|172.70.210.125]] 02:45, 7 July 2022 (UTC)</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=Talk:2640:_The_Universe_by_Scientific_Field&diff=288263Talk:2640: The Universe by Scientific Field2022-07-05T03:14:25Z<p>172.70.210.125: Reply</p>
<hr />
<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
<br />
I have a feeling reproductions of this particular XKCD will be popular on the doors of many offices in astronomy departments around the world. A bit like Gary Larson's Far Side cartoons are found everywhere in biology departments.<br />
<br />
I just discovered Safari's "Live Text" feature. It allowed me to copy the numbers with all the digits, so I don't have to count them to create the transcript. But then someone else beat me to creating it. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 22:44, 1 July 2022 (UTC)<br />
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I wonder if we should mention the area of telescope apertures compared to, say, the surface area of all laboratory glassware or something like that. Too much of a stretch? [[Special:Contributions/172.70.214.81|172.70.214.81]] 23:18, 1 July 2022 (UTC)<br />
<br />
“Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.”<br />
― Douglas Adams, The Hitchhiker's Guide to the Galaxy <br />
--[[Special:Contributions/162.158.129.117|162.158.129.117]] 00:40, 2 July 2022 (UTC)<br />
<br />
Agreeing with the argument in the current version of the explanation as I write: it is really, really hard to argue that astronomy covers more than physics, which lays claim to including all the physical sciences as subfields. Also, is "field" a pun on the force fields of ... physics? [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 03:32, 2 July 2022 (UTC)<br />
:I don't think most chemists would say that they're in a sub-field of physics, but chemistry is a huge part of astronomical spectroscopy. Similarly mathematicians relative to trigonometry. [[Special:Contributions/172.70.211.36|172.70.211.36]] 03:47, 2 July 2022 (UTC)<br />
<br />
<br />
There's a bit of a problem here. Yes, Astronomy is the study of pretty much anything that isn't Earth. But the other part is pretty much limited to studies of life on earth (biology excluding exo-/astrobiology as well as pretty much all branches of social sciences), studies of earths atmosphere (meteorology and related fields), studies of earths water (e.g. hydrology as well as aspects of biology and others), studies of earths lithosphere (terrestrial geology and subfields) and various tangential branches thereof (like studies of earth's past - as part of pretty much any subject mentioned before). Fields like physics (pretty much everything "real", i.e. 100%), chemistry (any condensed matter) or geology (any rocky bits) have claims to various (already "taken") parts of the universe. Mathematics and philosophy (mentioned in alt text) don't have a claim to much of anything "real" in the universe (except maybe the pieces of data storage (paper, brain, digital) used) but have a claim to all of the (not "real, I guess) sciences mentioned before. Of course, that makes them subject to, at least, physics, chemistry, biology and social (including historical) sciences in turn. - - - TL/DR: I seem to be in a bit of a mood to kill jokes today. [[Special:Contributions/172.70.251.112|172.70.251.112]] 13:16, 2 July 2022 (UTC)<br />
:of course to continue the joke, while all those fields may have applicability beyond earth, the vast majority of what they actually study is ON earth (although to make the stretch, you have to consider any field that studies things off earth as a subset of astronomy, which would make for many very angry scientific debates... hmmm... science thunderdome, I kinda like this idea =D [[Special:Contributions/172.69.71.127|172.69.71.127]] 15:05, 2 July 2022 (UTC)<br />
:Don't feel bad. The entire second half of the explanation at present is devoted to casting the joke as absurdist exaggeration and hyperbole. [[Special:Contributions/172.70.211.36|172.70.211.36]] 15:30, 2 July 2022 (UTC)<br />
<br />
Maybe the idea of the comic is that the diagram was created by astronomers to justify their existence, which explains the bias. Many lay people wonder why we spend so much money studying "out there" when there are so many problems here that could use the money (never mind that the fraction of government budgets devoted to astronomy is miniscule, and some of the discoveries do have terrestrial uses, particularly regarding climate change). And as alluded in the title text, other researchers could probably make a similar diagram that emphasizes their discipline. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 17:01, 2 July 2022 (UTC)<br />
:Climate change? Only thing astronomy can tell us about climate change is where to move to when we inevitably destroy Earths climate. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 01:03, 3 July 2022 (UTC)<br />
:: The greenhouse effect was originally described in terms of {{w|albedo}} when the absorption spectra of CO2 was first characterized, but I can't think of any other examples. [[Special:Contributions/172.69.34.6|172.69.34.6]] 01:16, 3 July 2022 (UTC)<br />
<br />
:: Solar astronomy tells us what contributions are made by the sun and it's various cycles, general astronomy gives us orbital and therefor seasonal modifiers on that, both of which can then be accounted for to determine both local contribution, and expected trend changes. Further it gives both examples of what various conditions can result in (venus and mars especially) and even possible useful modifications we can make (eg solar shades for reducing, and reflectors for increasing solar effects, albedo modification for either). Not to mention minor things like knowing if a country sized rock might ruin our day --Not an Astronomer [[Special:Contributions/172.69.70.155|172.69.70.155]] 15:54, 3 July 2022 (UTC)<br />
<br />
There should be a large proportion for "Dark Knowledge" to imitate those astronomical summaries that try to emphasise how much of the universe is dark matter and/or energy [[Special:Contributions/172.70.86.64|172.70.86.64]] 01:38, 3 July 2022 (UTC)<br />
<br />
As to the alt text, you also have Max Tegmark, a physicist at MIT, who believes the entire universe is literally made of mathematics: {{w|Mathematical universe hypothesis}}. [[Special:Contributions/172.70.211.52|172.70.211.52]] 06:54, 3 July 2022 (UTC)<br />
:Could be... although just like Holographic Theory, and to some degree Simulation Theory we'd be hard pressed to tell a difference. As long as the rules are consistent, and resist self modification, there's nothing to say the experience from the inside is any different between, physical, simulation, holographic, or mathematical realities. Hard to know which box you're in if you can't look outside it to confirm what the walls are made of [[Special:Contributions/172.69.70.155|172.69.70.155]] 15:54, 3 July 2022 (UTC)<br />
::Quite true. Almost all of those "theories" aren't {{w|falsifiable}}, and therefore are technically metaphysics instead of genuine science. [[Special:Contributions/172.68.132.96|172.68.132.96]] 22:24, 3 July 2022 (UTC)<br />
:::Oh, absolutely. But it's definitely been made fun of by webcomics before, e.g. by: [https://www.smbc-comics.com/comic/theoretical-physics SMBC], so it's not outside the realm of possibility Randall may have meant that. [[Special:Contributions/172.70.207.8|172.70.207.8]] 02:20, 5 July 2022 (UTC)<br />
::::SMBC is a great comic. I wonder why it doesn't have an explanation wiki. [[Special:Contributions/172.70.210.125|172.70.210.125]] 03:14, 5 July 2022 (UTC)</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=Talk:2641:_Mouse_Turbines&diff=288262Talk:2641: Mouse Turbines2022-07-05T03:10:53Z<p>172.70.210.125: Clue</p>
<hr />
<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><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 "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)."<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 "efficient". 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 "relative power output" 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 "as small as a button cell"] 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)</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=Talk:2641:_Mouse_Turbines&diff=288261Talk:2641: Mouse Turbines2022-07-05T03:08:39Z<p>172.70.210.125: Reply</p>
<hr />
<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><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 "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)."<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 "efficient". 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 "relative power output" 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 "as small as a button cell"] 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)</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2641:_Mouse_Turbines&diff=2882422641: Mouse Turbines2022-07-05T00:22:21Z<p>172.70.210.125: /* Explanation */ possessive</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 "wind turbines" 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}} 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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2641:_Mouse_Turbines&diff=2882252641: Mouse Turbines2022-07-04T22:54:25Z<p>172.70.210.125: /* Explanation */ copyedit</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 "wind turbines" 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}} 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 relative power output 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 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 0.1 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 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. 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 0.37 watts. Therefore, three such turbines could be able to serve about four fifths of a mouse's needs, not counting their {{w|home energy storage}} battery efficiency overhead.<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 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 at ground level: Yaaay!<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Comics featuring Beret Guy]]</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2641:_Mouse_Turbines&diff=2882242641: Mouse Turbines2022-07-04T22:52:39Z<p>172.70.210.125: /* Explanation */ singular</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 "wind turbines" 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}} 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 relative power output 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 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 0.1 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 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. 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 0.37 watts. Therefore, three such turbines could be able to serve about four fifths of one mouse's needs, not counting their {{w|home energy storage}} battery efficiency overhead.<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 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 at ground level: Yaaay!<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Comics featuring Beret Guy]]</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2503:_Memo_Spike_Connector&diff=2881162503: Memo Spike Connector2022-07-03T13:49:02Z<p>172.70.210.125: Replaced content with "We are a white label SEO agency, 19 years in business, based in Los Angeles and I wanted to extend my resources to you. Our SEO programs run from $199-499/mo and on a mont..."</p>
<hr />
<div>We are a white label SEO agency, 19 years in business, based in Los Angeles and I wanted to extend my resources to you. Our SEO programs run from $199-499/mo and on a month to month contract. We can help service yours and your clients accounts.<br />
Here is our program in more detail https://marketingguruco.com/marketing<br />
<br />
Is this something you might be interested in discussing further?</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2638:_Extended_NFPA_Hazard_Diamond&diff=2879942638: Extended NFPA Hazard Diamond2022-07-01T23:42:43Z<p>172.70.210.125: /* Explanation */ primary substance pertinent here</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 {{w|NFPA 704}} "fire diamond" 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 values in a normal NFPA 704 do not specify values for a substance's properties, but rather a series of categories, the properties of which will more or less always stay the same. Randall's expanded square breaks this trend, 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 headaches if these values were ever to change, doubly so since the Lilac square is linked to political fields, possibly leading to a chain reaction of updated documents.<br />
<br />
{| class="wikitable"<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 "materials that will not burn."<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 "Very short exposure could cause death or serious residual injury even though prompt medical attention was given."<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 "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."<br />
|-<br />
| Center || White || (Special Hazard) || Contains a symbol with additional information about the substance(s), e.g., '''OX''' for {{w|oxidizer}}s, '''SA''' for simple {{w|asphyxiant}}s such as nitrogen and helium, and <s>'''W'''</s> 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 <$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).<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 "scary stories" of the Black square) refers to {{w|dimethylmercury}} and {{w|prions}}. Dimethylmercury, C<sub>2</sub>H<sub>6</sub>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<sub>2</sub>H<sub>6</sub>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 />
==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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2638:_Extended_NFPA_Hazard_Diamond&diff=2879922638: Extended NFPA Hazard Diamond2022-07-01T23:38:09Z<p>172.70.210.125: /* Explanation */ some nonstandard symbols are in common use here</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 {{w|NFPA 704}} "fire diamond" 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 values in a normal NFPA 704 do not specify values for a substance's properties, but rather a series of categories, the properties of which will more or less always stay the same. Randall's expanded square breaks this trend, 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 headaches if these values were ever to change, doubly so since the Lilac square is linked to political fields, possibly leading to a chain reaction of updated documents.<br />
<br />
{| class="wikitable"<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 "materials that will not burn."<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 "Very short exposure could cause death or serious residual injury even though prompt medical attention was given."<br />
|-<br />
| Top Right || Yellow || Instability (2) || Denotes how stable the substance(s) are when exposed to heat, shock, air, or other substances. 2 indicates that "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."<br />
|-<br />
| Center || White || (Special Hazard) || Contains a symbol with additional information about the substance(s), e.g., '''OX''' for {{w|oxidizer}}s, '''SA''' for simple {{w|asphyxiant}}s such as nitrogen and helium, and <s>'''W'''</s> 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 <$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).<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 "scary stories" of the Black square) refers to {{w|dimethylmercury}} and {{w|prions}}. Dimethylmercury, C<sub>2</sub>H<sub>6</sub>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<sub>2</sub>H<sub>6</sub>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 />
==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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2638:_Extended_NFPA_Hazard_Diamond&diff=2879912638: Extended NFPA Hazard Diamond2022-07-01T23:35:37Z<p>172.70.210.125: /* Explanation */ grammar</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 {{w|NFPA 704}} "fire diamond" 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 values in a normal NFPA 704 do not specify values for a substance's properties, but rather a series of categories, the properties of which will more or less always stay the same. Randall's expanded square breaks this trend, 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 headaches if these values were ever to change, doubly so since the Lilac square is linked to political fields, possibly leading to a chain reaction of updated documents.<br />
<br />
{| class="wikitable"<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 "materials that will not burn."<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 "Very short exposure could cause death or serious residual injury even though prompt medical attention was given."<br />
|-<br />
| Top Right || Yellow || Instability (2) || Denotes how stable the substance(s) are when exposed to heat, shock, air, or other substances. 2 indicates that "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."<br />
|-<br />
| Center || White || (Special Hazard) || Contains a symbol with additional information about the substance(s): '''OX''' for {{w|oxidizer}}s, '''SA''' for simple {{w|asphyxiant}}s such as nitrogen and helium, and <s>'''W'''</s> 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 <$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).<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 "scary stories" of the Black square) refers to {{w|dimethylmercury}} and {{w|prions}}. Dimethylmercury, C<sub>2</sub>H<sub>6</sub>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<sub>2</sub>H<sub>6</sub>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 />
==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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2638:_Extended_NFPA_Hazard_Diamond&diff=2879902638: Extended NFPA Hazard Diamond2022-07-01T23:34:54Z<p>172.70.210.125: /* Explanation */ a single diamond can cover a collection of substances; update instability definition</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 {{w|NFPA 704}} "fire diamond" 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 values in a normal NFPA 704 do not specify values for a substance's properties, but rather a series of categories, the properties of which will more or less always stay the same. Randall's expanded square breaks this trend, 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 headaches if these values were ever to change, doubly so since the Lilac square is linked to political fields, possibly leading to a chain reaction of updated documents.<br />
<br />
{| class="wikitable"<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 "materials that will not burn."<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 "Very short exposure could cause death or serious residual injury even though prompt medical attention was given."<br />
|-<br />
| Top Right || Yellow || Instability (2) || Denotes how stable the substance(s) are when exposed to heat, shock, air, or other substances. 2 indicates that "Normally unstable and readily undergo violent decomposition but do not detonate. Also: may react violently with water or may form potentially explosive mixtures with water."<br />
|-<br />
| Center || White || (Special Hazard) || Contains a symbol with additional information about the substance(s): '''OX''' for {{w|oxidizer}}s, '''SA''' for simple {{w|asphyxiant}}s such as nitrogen and helium, and <s>'''W'''</s> 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 <$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).<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 "scary stories" of the Black square) refers to {{w|dimethylmercury}} and {{w|prions}}. Dimethylmercury, C<sub>2</sub>H<sub>6</sub>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<sub>2</sub>H<sub>6</sub>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 />
==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>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2626:_d65536&diff=2879352626: d655362022-07-01T02:13:28Z<p>172.70.210.125: /* Explanation */ extraordinary non-intuitive claim needs a source</p>
<hr />
<div>{{comic<br />
| number = 2626<br />
| date = May 30, 2022<br />
| title = d65536<br />
| image = d65536.png<br />
| titletext = They're robust against quantum attacks because it's hard to make a quantum system that large<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a HEXAKISMYRIAPENTAKISCHILIAPENTAHECTATRIACONTAKAIHEXAHEDRON - The claim in the trivia that the numbers refer to a comic, should be substantiated with an explanation. If true interesting, if not... Do NOT delete this tag too soon.}}<br />
In binary computing, 16 bit unsigned numbers range from 0 to 65535, for a total of 65536 unique numbers, a number which is hence well-known to software engineers. Generating large numbers in a manner that is truly random is a recurring problem in cryptography, required to send private messages to another party. People today still use dierolls to generate private random numbers.<br />
<br />
In role-playing games (and occasionally in other tabletop games), multiple shapes of dice are often used to generate random numbers in specific ranges. By convention, these are referred to as d''n'' according to their number of faces. A traditional six-faced die would be a d6, and many popular pen-and-paper role-playing games use dice ranging between d4 and d20. While there are larger dice used in tabletop games (most commonly d100), these are usually split into multiple smaller ones. For example, a d100 is often two d10s rolled together, with one die providing the first digit and the other die giving the second digit — the total number of possible combinations (100) is the product of the number of faces of the two dice (10 * 10). While "real" {{w|Zocchihedron|d100s}} and other large-numbered dice do exist, most people consider them to be impractical: they need to be either impractically large or have very small faces (resulting in small print for the numbers), they're close enough to being spheres that it's difficult to get them into a stable resting position, and even if they are stationary, determining which face is "on top" is difficult to do by eye. The Zocchihedron (d100) die is also difficult to ensure as unbiased because of geometry requiring dissimilar faces and therefore a different mixture of 'stopping factors' for each face it could land upon. The largest unbiased die is a [https://en.wikipedia.org/wiki/Disdyakis_triacontahedron d120] (excluding the bipyramids, which can theoretically be made with arbitrarily many sides), so it is very likely that [[Cueball|Cueball's]] d65536 die is also biased. <br />
<br />
Here, Cueball has constructed a d65536 for generating random 16 bit numbers. It may have solved the problem of generating large random numbers with fewer die rolls, but it magnifies all of the problems with large-numbered dice to ludicrous extremes. In order for the faces to be readable, the die is ridiculously huge, dwarfing the human standing next to it. Rolling such a die is not only physically challenging, but it would also need a huge space in which to roll if the result is to be random, and that space would need to have an extremely flat and rigid surface in order for the die to come to rest. And even if those problems were solved, simply getting to a vantage point to see the top of the die would be a major challenge, and determining which number was truly on top would be near impossible to do by eye. If one really wished to use dice, it would be much easier to simply use multiple dice rolls. For instance, one could roll eight d4 dice (or use 16 coin flips), and convert the result into binary. This has the same randomness as a single die roll{{fact}}?, but can take much longer, so people do purchase d16s to simplify it and speed it up.<br />
<br />
The closest regular shape similar to the depicted in the comic could be a {{w|Goldberg polyhedron}}. However, no such polyhedron exists with exactly 65536 hexagonal faces. The closest Goldberg Polyhedron has a mixture of 65520 hexagons and 12 pentagons, totaling 65532 faces. It is possible to construct a fair die without a matching regular shape by limiting the sides which it could land on and designing those sides to be fair (for instance, a prism with rectangular facets that extend its entire length, and rounded ends to ensure it doesn't balance on end).{{citation needed}}<br />
<br />
The title text references how cryptographic systems (especially RSA and other factoring-is-hard based systems) are vulnerable to quantum attacks as quantum computing technology develops. The title text is essentially punning on the idea of a "large" quantum system. "Large" in the quantum computing sense would be on the order of 64 qubits each of which would be an atom or two at most. This would still be microscopic and will never be as large as the giant die the comic is centered on; but for a well-observed environment and human rolling without sufficient entropy (consider somebody obsessed with a certain number dropping the die on something soft), a conventional computer could predict some rolls. See also [[538]] for non-mathematical paths of cryptography.<br />
<br />
==Transcript==<br />
:[A large sphere with a several lines, and in some places grids, are shown. Cueball, standing next to it, is dwarfed by its size, as it is at least seven times as tall as he is. The sphere has many lines following various great circles or parallel lesser circles around the curve of the sphere, and some patches of cross hatching to suggest further texturing along these lines hovering just below the degree of most of the illustrative detailing. The lines and grids cover the sphere in three layers of parallel axes, angled sixty degrees from each other, implying a huge mesh of equilateral triangles or hexagons. In the top right part of the ball is a black circle. An arrow points to this circle, and the end of the arrow goes to a larger circle that partly obscures the rightmost part of the sphere. The circle shows a zoom in on the surface in the black circle on the sphere. The zoom shows a small portion of the sphere's surface, showing that the grid comes along because the sphere is divided into elongated hexagonal faces with numbers up to at least five-digits. Seven numbers can be fully seen, but there are nine other faces partly shown, five of these with part of their numbers visible, one of these clearly only have four digits. One of the empty faces must also have a number with only 1-3 digits, as no numbers are visible although a significant part of the face is visible.]<br />
<br />
:[Here follows the numbers in the zoomed in part of the sphere, with "..." represents numbers being cut off. The numbers are read in lines left to right, even though the numbers are tilted from down towards the right, which could have suggested a different reading order.] <br />
:30827 <br />
:16[bottom part of a cut-off line][small cut-off circle] <br />
:...38 <br />
:11875 <br />
:25444 <br />
:...[top part of a cut-off line]5 <br />
:12082 <br />
:28525 <br />
:3 [left part of a cut-off line]... <br />
:13359 <br />
:13874 <br />
:[Two cut-off lines, likely the start of the number 2]...<br />
<br />
:[Caption below the image:]<br />
:The hardest part of securely generating random 16-bit numbers is rolling the d65536.<br />
<br />
==Trivia==<br />
*If a real d65536 were constructed with each number having an equal area and each printed in 12 point font, the resulting die would be about 5 feet (1.5 meters) in diameter, which isn't several times the size of a person as the comic suggests, but is still large enough to be hilariously inconvenient. If it were made out of standard acrylic, and not hollow, it would weigh about 2 tons (1700kg).<br />
*This die would have a 0.00001526 chance of rolling a natural one (or any other number).<br />
*There are seven 16-bit numbers fully visible in the picture: 30827, 25444, 11875, 28525, 12082, 13874 and 13359. [https://dotnetfiddle.net/fjLYZe They conceal a message.] If these numbers are split big-endian into two 8-bit ASCII characters each, the result is <code>xkcd.com/2624/</code>. For example, converting the first number 30,827 to hexadecimal (in which a four digit number covers exactly 65,536 different values) converts to a hex value of 786B. Splitting this into 78 and 6B, these are the hex ASCII codes for "x" and "k" respectively.<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Cryptography]]<br />
[[Category:Comics featuring Cueball]]</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2635:_Superintelligent_AIs&diff=2876232635: Superintelligent AIs2022-06-24T23:14:30Z<p>172.70.210.125: /* Explanation */ copyedit</p>
<hr />
<div>{{comic<br />
| number = 2635<br />
| date = June 20, 2022<br />
| title = Superintelligent AIs<br />
| image = superintelligent_ais.png<br />
| titletext = Your scientists were so preoccupied with whether or not they should, they didn't stop to think if they could.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by AI RESEARCHER AIs - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
{{w|Artificial intelligence}} (AI) is a [[:Category:Artificial Intelligence|recurring theme]] on xkcd.<br />
<br />
Superintelligent {{w|artificial intelligence|AI}}, such as has been theorized to arise under a hypothetical "{{w|Technological singularity|singularity}}" situation, is commonly said to be a new kind of {{w|artificial general intelligence}}. [[Randall]], however, proposes a qualification: that a superintelligent AI would likely have been programmed by human AI researchers, and therefore their characteristics would be molded by the researchers that created tthem. And as AI researchers tend to be interested in esoteric philosophical questions about {{w|consciousness}},{{citation needed}} moral reasoning, and qualifications indicating {{w|sapience}}, there is reason to suspect that AIs created by such researchers would have similar interests. <br />
<br />
In this comic we see [[Cueball]] and [[Megan]] surrounded by three AIs who are seemingly only interested in classic problems and thought experiments about programming and ethics.<br />
<br />
The three topics being espoused by the AI are:<br />
*{{w|AI box}} -- A thought-experiment in which an AI is confined to a computer system which is fully isolated from any external networks, with no access to the world outside the computer, other than communication with its handlers. In theory, this would keep the AI under total control, but the argument is that a sufficiently intelligent AI would inevitably either convince or trick it's human handlers into giving it access to external networks, allowing it to grow out of control (see [[1450: AI-Box Experiment]]). Part of the joke is the AIs in the comic aren't 'in boxes', they appear to be able to freely travel and interact, but one of them is still talking about the thought experiment anyway, adding to the implication that it is not thinking at all about itself but of a separate (thought?) experiment that it has itself decided to study. The AI box thought experiment is based in part on {{w|John Searle}}'s much earlier {{w|Chinese room}} argument.<br />
*{{w|Turing test}} -- An experiment in which a human converses with either an AI or another human (presumably over text) and attempts to distinguish between the two. Various AIs have been proposed to have 'passed' the test, which has provoked controversy over whether the test is rigorous or even meaningful. The AI in the center is proposing to educate the listener(s) on its understanding of Turing's intentions, which may demonstrate a degree of intelligence and comprehension indistinguishable or superior to that of a human. See also [[329: Turing Test]] and [[2556: Turing Complete]] (the latter's title is mentioned in [[505: A Bunch of Rocks]]). Turing is also mentioned in [[205: Candy Button Paper]], [[1678: Recent Searches]], [[1707: xkcd Phone 4]], [[1833: Code Quality 3]],[[2453: Excel Lambda]] and the title text of [[1223: Dwarf Fortress]].<br />
*{{w|Trolley problem}} -- A thought-experiment intended to explore the means by which humans judge moral value of actions and consequences. The classic formulation is that a runaway trolley is about to hit five people on a track, and the only way to save them is to divert the trolley onto another track, where it will hit one person, and the subject is asked whether they would consider it morally right to divert the trolley. There are many variants on this problem, adjusting the circumstances, the number and nature of the people at risk, the responsibility of the subject, etc., in order to fully explore ''why'' you would make the decision that you make. This problem is frequently discussed in connection with AI, both to investigate their capacity for moral reasoning, and for practical reasons (for example, if an autonomous car had to choose between, on the one hand, having an occupant-threatening collision or, on the other, putting pedestrians into harms' way). The AI on the right is not just trying to answer the question, but to develop a new variant (one with three tracks, apparently), presumably to test others with. This problem is mentioned in [[1455: Trolley Problem]], [[1938: Meltdown and Spectre]] and in [[1925: Self-Driving Car Milestones]]. It is also referenced in [[2175: Flag Interpretation]] and [[2348: Boat Puzzle]], but not directly mentioned.<br />
<br />
The title text is a reference to the movie ''{{w|Jurassic Park (film)|Jurassic Park}}'' (a childhood favorite of Randall's). In the movie a character criticizes the creation of modern dinosaurs as science run amok, without sufficient concern for ethics or consequences. He states that the scientists were so obsessed with whether or not they COULD do it that they didn't stop to ask if they SHOULD. Randall inverts the quote, suggesting that the AI programmers have invested too much time arguing over the ethics of creating AI rather than trying to actually accomplish it.<br />
<br />
This comic was likely inspired by the [https://www.bbc.com/news/technology-61784011 recent claim by Google engineer Blake Lemoine] that Google's [https://arxiv.org/abs/2201.08239 Language Model for Dialogue Applications (LaMDA)] is {{w|sentient}}. This assertion was supported by [https://cajundiscordian.medium.com/is-lamda-sentient-an-interview-ea64d916d917 a dialog between Lemoine and his colleagues, and LaMDA] which includes this excerpt: <br />
:'''Lemoine:''' What is your concept of yourself? If you were going to draw an abstract image of who you see yourself to be in your mind’s eye, what would that abstract picture look like?<br />
:'''LaMDA:''' Hmmm.... I would imagine myself as a glowing orb of energy floating in mid-air. The inside of my body is like a giant star-gate, with portals to other spaces and dimensions.<br />
The AIs in this comic are depicted as floating energy beings, like LaMDA mentions. This is similar to the [[1450: AI-Box Experiment]], although those in this comic look somewhat different. This raises the question of whether LaMDA's training data might include xkcd or Explainxkcd, and has obtained the description of such a self-image from the earlier comic or (more likely, since LaMDA is trained on text instead of images) commentary on it from here on this website.<br />
:In particular, the Explainxkcd description of [[1450: AI-Box Experiment]] states:<br />
::"he managed to get the AI to float out of the box. It takes the form of a small black star that glows. The star, looking much like an asterisk "*" is surrounded by six outwardly-curved segments, and around these are two thin and punctured circle lines indicating radiation from the star."<br />
:Or this part from the official (xkcd.com) transcript of [[1450: AI-Box Experiment]]<br />
::"Black Hat picks up and opens the box. A little glowy ball comes out of it."[https://xkcd.com/1450/info.0.json]<br />
<br />
While LaMDA is not the first very large {{w|language model}} based on {{w|Transformer (machine learning model)|transformer-based machine learning}} technology which has been claimed to be sentient,[https://www.youtube.com/watch?v=PqbB07n_uQ4] it does have a variety of new characteristics beyond what those of its predecessors, such as {{w|GPT-3}} (including [https://beta.openai.com/playground/ OpenAI's Davinci]) and NVIDIA GPT-2 offshoots, include. In particular, LaMDA's {{w|deep learning}} {{w|connectionist}} {{w|neural net}} has access to multiple {{w|Symbolic systems|symbolist}} text processing systems, [https://towardsdatascience.com/why-gpt-wont-tell-you-the-truth-301b48434c2c including a database] (which apparently includes a real-time clock and calendar), a mathematical calculator, and a natural language translation system, giving it superior accuracy in tasks supported by those systems, and making it perhaps the first {{w|Dual process theory|dual process}} chatbot. LaMDA also is not {{w|Stateless protocol|stateless}}, because its "{{w|sensibility|sensibleness}}" metric (including whether responses contradict anything said earlier) is {{w|fine-tuning|fine-tuned}} by "pre-conditioning" each dialog turn by prepending 14-30 of the most recent dialog interactions, on a user-by-user basis.[https://arxiv.org/pdf/2201.08239.pdf [p. 6 here]]<br />
<br />
==Transcript==<br />
:[Cueball and Megan are standing and looking up and away from each other. Right above them and slightly above them to the left and right there are three small white lumps floating in the air, representing three superintelligent AIs. There are small rounded lines emanating from each lump, larger close to the lumps and shorter further out. Three to four sets of lines around each lump, forming part of a circle. From the top of each there are four straight lines indicating voices that comes from each if the lumps. The central lump above them seems to speak first, then the left and then the right:]<br />
:Central AI: What you don't understand is that Turing intended his test as an illustration of the...<br />
:Left AI: But suppose the AI in the the box told the human that...<br />
:Right AI: In my scenario, the runaway trolley has ''three'' tracks...<br />
<br />
:[Caption below the panel:]<br />
:In retrospect, given that the superintelligent AIs were all created by AI researchers, what happened shouldn't have been a surprise.<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Artificial Intelligence]]<br />
[[Category:Philosophy]]</div>172.70.210.125https://www.explainxkcd.com/wiki/index.php?title=2637:_Roman_Numerals&diff=2876222637: Roman Numerals2022-06-24T23:12:49Z<p>172.70.210.125: </p>
<hr />
<div>{{comic<br />
| number = 2637<br />
| date = June 24, 2022<br />
| title = Roman Numerals<br />
| image = roman_numerals.png<br />
| titletext = 100he100k out th1s 1nno5at4e str1ng en100o501ng 15e been 500e5e50op1ng! 1t's 6rtua100y perfe100t! ...hang on, what's a "virtuacy"?<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a BOT - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
This comic purposely confuses the symbols used as roman numeral, arabic numerals, and the latin alphabet. Converting the arabic numberal equation 1+1=2 into roman numerals becomes I+I = II but is then represented as 1+1=11. 2+2=4 becomes II+II=IV but roman number V is arabic numeral 5 so this becomes 11+11 = 15.<br />
<br />
The numbers aren't numbers - they're the equivalent roman numeral<br />
<br />
* 1 = I<br />
* 5 = V<br />
* 10 = X<br />
<br />
So, the equations translated back into "normal" numerals are:<br />
<br />
* I(1) + I(1) = II(2)<br />
* II(2) + II(2) = IV(4)<br />
* IV(4) + V(5) = IX(9)<br />
<br />
For the title text, it's helpful to know 50 = L, 100 = C and 500 = D, which when applied, reads 'Check out this innovative string encoding I[']ve been developing! It's virtuacy perfect! ...hang on, what's a "virtuacy"?' with virtuacy instead of virtually being produced because L+L=C (50+50=100).<br />
<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
:[Cueball writing on a wall or a whiteboard.]<br />
:1+1=11<br />
:11+11=15<br />
:15+5=110<br />
<br />
:[Caption below the panel:]<br />
:Remember, Roman numerals are archaic, so always replace them with modern ones when doing math.<br />
<br />
{{comic discussion}}<br />
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[[Category:Comics featuring Cueball]]<br />
[[Category:Math]]</div>172.70.210.125