explain xkcd - User contributions [en]

Talk:2975: Classical Periodic Table

2024-11-18T20:27:27Z

172.71.222.6:

I checked the Actinides and it looks like the criteria for "fire" is half-life < 1 day. [[User:SpriteGuard|SpriteGuard]] ([[User talk:SpriteGuard|talk]]) 18:11, 21 August 2024 (UTC)
:I would have found it funnier, if only on table-esthetic grounds, if all radioactive elements had been filed as Fire. (I'm a chemist.) [[Special:Contributions/198.41.242.175|198.41.242.175]] 07:58, 22 August 2024 (UTC)

The four classical Elements are still recognised by scientists; They just repurposed the word "element", and so have adopted "state" to describe this older classification - Solid, Liquid, Gas and Plasma exactly map to the classical 'elements'. I think we can forgive the medieval alchemical community for not recognising Bose-Einstein Condensate as their fifth element. [[Special:Contributions/172.68.64.149|172.68.64.149]] 21:05, 21 August 2024 (UTC)
:what about non-newtonian fluids? [[User:42.book.addict|42.book.addict]] ([[User talk:42.book.addict|talk]]) 22:17, 21 August 2024 (UTC)
::They're fluids... turns out. [[Special:Contributions/172.70.126.229|172.70.126.229]] 04:47, 22 August 2024 (UTC)
:If the 2016 movie "[https://en.wikipedia.org/wiki/Spectral Spectral]" is to be believed, then Bose–Einstein condensates maps to ghosts. [[Special:Contributions/172.68.0.167|172.68.0.167]] 23:26, 21 August 2024 (UTC)
Everyone knows that the 5th element is Leeloo Dallas. Obviously the Bose-Einstein Condensate would have to be the 6th Element.[[Special:Contributions/172.70.111.60|172.70.111.60]] 15:00, 22 August 2024 (UTC)
:That agrees with the comment (currently) above. If you can sense one of those, you can probably also see dead people... [[Special:Contributions/172.70.90.207|172.70.90.207]] 20:00, 22 August 2024 (UTC)

He's done this comparison between 'classical' and 'modern' elements before... for example in comic #965. [[Special:Contributions/172.70.58.3|172.70.58.3]] 05:52, 22 August 2024 (UTC)

I did what I could for the Fire section earlier, and I've just gone back and added some relevant What-If context for both Mercury and Astatine. The latter is nasty stuff - lucky it can't really exist under standard temperature and pressure, or we'd all be screwed. [[User:Darkwolf218|Darkwolf218]] ([[User talk:Darkwolf218|talk]]) 08:45, 22 August 2024 (UTC)
:The issue of STP doesn't really apply to the whole "fire" grouping, anyway. The thing making them "fire" is not really influenced by changes in temperature and pressure (not unless you're going the way of stellar temperatures and being pressured by an essentially neutronium soup, but we're drifting into many more things being dragged into this, ultimately). The likes of phosphorous is not shown as "fire", when it can be indeed aflame under STP (to not be, you have to ensure the pressure is not from ''our typical mix of'' "air", but one which is quite a bit less reactive), and I'm really not sure (without looking up likely examples) how many of the non-"fire" elements (other than itself, of course) would not effectively set on fire if the pressure requirements was to be provided by a fluorine atmosphere...
:But any concept of "standard temperature, pressure ''and environment''" is obviously beyond the scope of this humorous take. One could even imagine that it be "an infinite space" of the target (nonclassical) element (c.f. "infinite plane" assumptions), without boundary or container, but how that effects the fire/earth boundary of certain radioactive materials (w.r.t. the ability to have a critical density, given a supercritical mass ''without'' being forced together) I think is not necessarily open (or easily obtained) information. [[Special:Contributions/172.70.160.220|172.70.160.220]] 12:17, 22 August 2024 (UTC)
:Phosphorous combines with other elements, like oxygen, to make fire. Radioactive elements produce heat and sometimes higher-frequency light (i.e. "fire") ''all by themselves''. STP with neon as the gas might be a good starting point to think about this, although I wouldn't bet against neon interacting at least a little with some of the more aggressive fire elements. [[Special:Contributions/162.158.155.191|162.158.155.191]] 19:40, 23 August 2024 (UTC)
::To be most sure (given fluorine's actual reactiveness with elements that have more stealth 'shell slots' available to attach to), I'd suggest helium over any other choice. Assuming you [[2766: Helium Reserve|have it]] or [[2972: Helium Synthesis|can get it]], naturally.
::Though, as pointed out, the tendencies of radioactivity really aren't subject to temperature or (short of metals being compressed to super-criticality in nuclear-weapons, which isn't really the same thing) pressure in any way. These do dictate the precise memberships of the non-Fire elements (you can freeze mercury or melt sodium or condense nitrogen, etc), but talking of STP isn't really so necessary in the context of the 'firey fringes', assuming it's based upon arbitrarily-timed half-life-length. [[Special:Contributions/172.70.162.163|172.70.162.163]] 21:34, 23 August 2024 (UTC)

I feel like Munroe just discovered the Aristotle Version of [https://tomlehrersongs.com/the-elements Tom Lehrer's song The Elements] {{unsigned ip|172.70.80.229|16:52, 4 September 2024 }}

Ironically, under this periodic table, H2O would be considered 100% pure earth {{unsigned ip|172.68.35.59|16:52, 1 October 2024}}

Who remembers the 21st night of September?

3010: Geometriphylogenetics

2024-11-14T23:47:18Z

172.71.222.6: /* Explanation */

{{comic
| number = 3010
| date = November 11, 2024
| title = Geometriphylogenetics
| image = geometriphylogenetics_2x.png
| imagesize = 316x391px
| noexpand = true
| titletext = There's a maximum likelihood that I'm doing phylogenetics wrong.
}}

==Explanation==
{{incomplete|Created by EUCLIDIAN GENOMETRY - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

{{w|Phylogenetics}} refers to the practice of examining relationships among things that follow the principle of "descent with modification of progeny". In the course of descent with modification, one thing may give rise to two (the progeny), different modifications happen to each, and those modifications become established. Iterated "splits" over time yield a tree of objects; it is the purpose of phylogenetics to recover ("reconstruct") these trees, and use the information gained to inform study of the things contained. Phylogenetics has been most commonly applied to the classification/taxonomy of biological species and investigations of their evolutionary history, but it has also been used to examine the evolution of genes and biosynthetic pathways. Similar conceptual approaches have been used in the study of human languages and their evolution.

Data for phylogenetic analyses may come from any attributes ("characters") of the things being examined. {{w|Computational_phylogenetics|Rigorous techniques}} for these analyses became available starting in the {{w|Willi_Hennig|1950s}}, and these replaced earlier methods based largely on the individual judgement of experts. In phylogenetic studies of organisms, their DNA is far and away the most data-dense source of information, and consequently, most present-day investigations are based on analyses of selected genes and, increasingly, whole genomes. Thanks to the advent of more robust datasets, and more robust methods of data analysis, it is now commonplace for studies, especially on relatively understudied creatures, to reconstruct an evolutionary history (a phylogeny) that is radically different from what had previously been assumed. This is the "phylogenetic revolution" referred to in the caption. One example is the genus {{w|Hippopotamus|<em>Hippopotamus</em>}}, which had been considered a relative of pigs, which the animals somewhat resemble, until modern data and methods revealed it to be more closely related to whales, despite the animals being very different physically (hippos spend time in water, but [https://www.youtube.com/watch?v=X-YRJCSZRJU can't swim]).

This comic presents a tree, which resembles and purports to be a phylogenetic tree, in which the endpoints ("terminal taxa") are geometric shapes. This has been given the name "geometriphylogenetics" — a portmanteau of "{{w|geometry}}" and "phylogenetics". The claim is that triangles have been moved from the lower part of the tree (where they would be closely related to squares, rectangles, pentangles, and the like) to the upper part (placing them closer to circles and ellipses). This is a riff on the findings, and even the wording, of authentic phylogenetic research papers that report "revolutionary" results. The absurdity, and the joke, is that geometries do not change over time. Human understanding might change, but triangles and circles and rectangles themselves did not evolve or descend from ancestors, they are not progeny of some other geometries of ages past, and therefore phylogenetic principles and techniques don't apply to their study. Moreover, geometries do not contain DNA,{{cn}} so genetic analysis, even if it was ever relevant, is impossible.

The title text alludes to {{w|Computational_phylogenetics#Maximum_likelihood|maximum likelihood}}, one of the most robust, and most frequently used, methodologies for phylogenetic analysis. The method builds a number of trees from the data, assigns to each a probability that it conforms to a pre-selected model of evolution, and then selects the tree that has the highest (maximum) likelihood of conformity to the model. In this case, though, the statement "There's a [high probability] that I'm doing phylogenetics wrong" doesn't just have the maximum probability of the available options; it has the maximum ''possible'' probability of 1, because it is definitely the case.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[A tree diagram, or a dendrogram is shown, consisting of lines that branch off from left to right, starting with one horizontal line on the left. Eight results are shown on the right: ellipse on Path 1, circle on Path 2, triangle on Path 3, parallelogram on Path 4, trapezoid on Path 5, square on Path 6, rectangle on Path 7, and a pentagon on Path 8. The paths are listed in order top to bottom.]
:[Path 3 and the triangle are bold black, while the other branches are dimmer. The paths are connected as follows: Path 2 and 3 are connected, then both connect together to Path 1; Path 4 and 5 are connected, as are Path 6 and 7, and these two paths are connected altogether; Path 8 is then connected to the branch containing Paths 4 to 7. All of Paths 1 to 3 are then connected to Paths 4 to 8, the branches all culminating in a single line on the left.]

:[Caption below the panel:]
:The phylogenetic revolution continues:
:Triangles were long believed to be related to squares, but genetic analysis proves that they are actually very pointy circles.

{{comic discussion}}

[[Category:Geometry]]
[[Category:Biology]]
[[Category:Charts]]
[[Category:Statistics]]

Talk:2966: Exam Numbers

2024-07-31T21:06:37Z

172.71.222.6:

pre-algebra: 4, calculus: pi^2 / 4 (about 2.467), physics: cosmological constant: depends on how you measure it [[Special:Contributions/162.158.167.48|162.158.167.48]] 18:11, 31 July 2024 (UTC)

Game theory: -5x10⁶ (maybe helpful, maybe not... just be thankful I didn't include an ''i'' factor in there somewhere...) [[Special:Contributions/172.70.162.185|172.70.162.185]] 18:20, 31 July 2024 (UTC)

Could somebody reformat all the math here in whatever LaTeX plugin this wiki uses? --[[Special:Contributions/162.158.222.102|162.158.222.102]] 18:35, 31 July 2024 (UTC)
:Probably not, because the MathML here is broken. But, also, nothing I see requires anything particularly complicated, it can all stay in fairly straightforward (standardly formatted) text. [[Special:Contributions/141.101.98.224|141.101.98.224]] 18:44, 31 July 2024 (UTC)
I had to look up "TREE(3)." Seriousness aside, I think the largest number would be the astrological sign 1 that has its end_points_ as galaxy clusters. [[Special:Contributions/172.68.245.184|172.68.245.184]] 19:26, 31 July 2024 (UTC)
Which astrological sign? Search engines aren't helping. [[User:Onestay|Onestay]] ([[User talk:Onestay|talk]]) 20:41, 31 July 2024 (UTC)
::The nonexistent one I just made up that looks like a "1." 😃 [[Special:Contributions/172.71.222.6|172.71.222.6]] 21:06, 31 July 2024 (UTC)
Infinity is _not_ a number. [[User:Dúthomhas|Dúthomhas]] ([[User talk:Dúthomhas|talk]]) 19:39, 31 July 2024 (UTC)

If infinity _is_ a number, it might be a possible solution to the game theory question. The average of any set of numbers that includes infinity is infinity, and infinity + 10 is still infinity. I probably wouldn't try that in most classes, but a game theory professor might approve "gaming" the system, as it were.
:If I would prefer no-one (else) to win, I might submit -∞ as my answer. [[Special:Contributions/172.70.90.74|172.70.90.74]] 20:13, 31 July 2024 (UTC)

Infinity is absolutely not a number, and is the one answer I would mark as unambiguously wrong for the last one. Just say TREE(G_64) or something. [[Special:Contributions/162.158.154.31|162.158.154.31]] 20:15, 31 July 2024 (UTC)
:This is correct. No one in post-grad math would write “infinity” and expect that answer to work. Infinity is NOT a number except for seven-year-olds. Yet the explanation above continues to posit it as a possible correct answer. [[User:Dúthomhas|Dúthomhas]] ([[User talk:Dúthomhas|talk]]) 20:49, 31 July 2024 (UTC)

I did a bit of a deep dive into wikipedia and the googology wiki and the answer to the last question depends on a few things (along with assuming ZFC). If transfinite ordinals count as numbers, then those at the end of {{w|List of large cardinal properties}} take the cake (if i'm reading it right). Otherwise, something based off [https://googology.fandom.com/wiki/Rayo%27s_number Rayo's number] is the best googologists have come up with so far. [[Special:Contributions/172.69.246.149|172.69.246.149]] 20:18, 31 July 2024 (UTC)Bumpf

Isn’t the joke in the pre-algebra that it would require algebra in order ro calculate? [[Special:Contributions/172.68.70.135|172.68.70.135]] 20:36, 31 July 2024 (UTC)
:Yes. I agree that it would be worth adding wording along the lines that “the joke here is that you need algebra to solve the equation”. [[User:Dúthomhas|Dúthomhas]] ([[User talk:Dúthomhas|talk]]) 20:56, 31 July 2024 (UTC)