explain xkcd - User contributions [en]

Talk:2552: The Last Molecule

2021-12-09T21:08:21Z

108.162.246.122:

Unsuccessfully tried to search for a match to the image of the chemical compound. Did find this, which is difficult to use on a cellphone: OSRA: Optical Structure Recognition: https://cactus.nci.nih.gov/cgi-bin/osra/index.cgi [[Special:Contributions/172.70.211.172|172.70.211.172]] 07:43, 9 December 2021 (UTC)
:I've tried to search for SMILES of the molecule, but also got nothing: https://pubchem.ncbi.nlm.nih.gov/#query=C1(C2CC(CCC)C(CC)C2(CCCC))C%3DCC(C(%3DCCC(%3DC)CC)C(C)C)%3DC1 [[Special:Contributions/162.158.222.137|162.158.222.137]]

I truly don't understand the God part of the current explanation. [[Special:Contributions/172.68.110.121|172.68.110.121]] 07:55, 9 December 2021 (UTC)
:There is an article at [https://www.smithsonianmag.com/smart-news/humans-make-110000th-earths-biomass-180969141/ Smithonian Magazine] that sums it up quite nicely: Of the 550 gigatons of biomass carbon on Earth, animals make up about 2 gigatons, with insects comprising half of that and fish taking up another 0.7 gigatons. Everything else, including mammals, birds, nematodes and mollusks are roughly 0.3 gigatons, with humans weighing in at 0.06 gigatons.
::About half of all known living species on earth are insects. Therefore if there was a god who created all life, it would be reasonable to assume he likes them. [[User:Bischoff|Bischoff]] ([[User talk:Bischoff|talk]]) 08:26, 9 December 2021 (UTC)

Chemistry. I love chemistry :-) There is a concept called "Chemical Space" that I learned about in school. https://en.wikipedia.org/wiki/Chemical_space may help, in short: Chemical space is a huge but finite space of all possible atom arrangements in molecules. [[Special:Contributions/162.158.91.106|162.158.91.106]] 07:59, 9 December 2021 (UTC)

I've heard the claim, that we know less about our own ocean floor than we do about the surface of Mars several times before. Is there actually a credible source for this and how do we even quantify how much we know about either area? [[User:Bischoff|Bischoff]] ([[User talk:Bischoff|talk]]) 08:26, 9 December 2021 (UTC)
:This essay might shed some light on the question. [[https://www.scientificamerican.com/article/just-how-little-do-we-know-about-the-ocean-floor/ Just How Little Do We Know about the Ocean Floor?]] From a geographical perspective, our maps of the ocean floor are much less detailed than those covering Mars. (5km resolution for ocean floor, 100m resolution for Mars - radar doesn't work underwater). [[Special:Contributions/162.158.107.18|162.158.107.18]] 09:25, 9 December 2021 (UTC)

The current explanation says that there are an infinite number of chemicals. Is that true? Source? Explanation how that is possible?
Obviously the number of possible molecules is huge, but is it actually a literal, mathematical infinite? Given a finite observable universe, with presumably a finite number of atoms in it. There appear to be a finite number of elements which are stable for any appreciable amount of time and capable of forming molecules.
It seems like there might be practical limitations to the size of a molecule, so that you can't keep making bigger and bigger ones just by adding more atoms/subunits?
If you just keep adding carbon atoms to a diamond will you eventually reach a point where forces such as gravitation become a factor and the molecular bonds fail? I can imagine that long chain molecules light years long might reach point where other forces overwhelm the bond strength? [[Special:Contributions/108.162.246.76|108.162.246.76]] 09:10, 9 December 2021 (UTC)
:For obvious reasons, as long as you limit the number of atoms involved the number of possible "molecules" is - in a mathematical sense - finite. (As there is only a finite number of reasonable stable elements.) But already simple things like polymers can bind millions of atoms in a single molecule. Together with the possible variations intrinsic to such polymers a simple "material" like phenolic resin [[https://en.wikipedia.org/wiki/Phenol_formaldehyde_resin]] is a mixture of more different chemical compounds (in a strict sense) than mankind can ever describe. For all practical application this compexity is not relevant, so no one really cares about.
Additionally there is no clear boundary between typical molecules and other types of condensed matter, like crystals. Same applies to biochemistry. Does chemistry include bio-molecules? If yes, the chemistry guy have to include all the gene sequencing in their to-do list.

"how fast does light travel in one direction?" is not a good example for incompleteness in physics, because this question was settled by Michelson and Morley in the 19th century (answer: it travels with the speed of light)
: It's not clear to me either what was meant here - seems out of place.
:We know how fast light travels when it goes somewhere and comes back – that's ''c'' – but we don't know how fast it goes when only traveling in one direction. For example, light going at ''c''/2 in one direction and returning instantaneously in the other would still match our observations. We also can't reliably synchronize clocks over a distance because we'd either have to do it with a speed-of-light delay, or separate two clocks and find that relativity changed the timings. Of course, Occam's razor indicates that a consistent speed is more likely, but that's not proof. [[Special:Contributions/172.70.126.87|172.70.126.87]] 12:42, 9 December 2021 (UTC)
:Observing two points (nominal source and nominal destination) from a third point perpendicularly off the mid-point between thoss two points, at an arbitrary distance, you ought to see if there's slowness or instaneity involved (at least make a comparison between bidirectional traversal). This does not remove a response bias in the signal from either end as sent towards the recorder at the observation point, but as the stand-off is increased it makes both observation paths nearer and nearer to parallel and so significantly removes the quantifiable initial 'sideways bias' that may exist.
:I leave it as an excercise to the reader to produce the reasons why this might not practically work to quash all such 'inbuilt universal asymmetry', but it's a good start! [[Special:Contributions/172.70.90.141|172.70.90.141]] 13:21, 9 December 2021 (UTC)
:I genuinely don't understand the confusion being proposed here; in practice it's trivial to synchronize a single photon emitter with a single photon detector (such as a PMT) and confirm the speed of light across a single path, with no return trip involved. As far as I know there is know precidence in QM to suspect bidirectional travel could be a special case.
:I like Veritasium as much as the next guy, but I don't think that this one is a serious debate like the other examples. If you're going to consider something like this a great unsolved mystery in physics, I'm sure there are countless other questions just like this for almost every topic in physics and not everything can be a great unsolved mystery.[[Special:Contributions/172.70.134.23|172.70.134.23]] 17:37, 9 December 2021 (UTC)

To quote Randall Munroe in https://what-if.xkcd.com/114/, "The whole universe is matter, as far as we can tell. No one is sure why there is more matter than antimatter, since the laws of physics are pretty symmetrical, and there's no reason to expect there to be more of one than the other. Although when it comes down to it, there's no reason to expect anything at all." Antimatter aside, this shows that the laws of the universe are sometimes asymmetrical. I also like the point that "when it comes down to it, there's no reason to expect anything." Why should we expect the speed of light to be symmetrical? There's no real reason to. [[User:Beret|Beret]] ([[User talk:Beret|talk]]) 14:53, 9 December 2021 (UTC)
:On the contrary, without any such thing as the æther (the fundament through which we would be passing) there is no reason to expect the speed of light (in any given frame of reference) to be asymmetrical. Relativistic frame-dragging and other distortions due to (or resulting in!) accelerative forces will act accordingly, but not change ''c'' itself, in proper calculations, as a function to direction. [[Special:Contributions/172.70.86.12|172.70.86.12]] 16:02, 9 December 2021 (UTC)

::https://en.wikipedia.org/wiki/One-way_speed_of_light In any case, the point is that there is no reason to expect light speed to be symmetrical, either. Asymmetry in this case is not due to frame dragging, it would be some fundamental feature of photons or the universe. There is currently no experimental way to test this. [[User:Beret|Beret]] ([[User talk:Beret|talk]]) 17:00, 9 December 2021 (UTC)

Maybe we can cite one of some famous declarations of physicist saying the physics is almost done [https://nautil.us/blog/the-comforting-certainty-of-unanswered-questions (taken from this site)] :

:The British scientist William Cecil Dampier recalled his apprenticeship at Cambridge in the 1890s: “It seemed as though the main framework had been put together once for all, and that little remained to be done but to measure physical constants to the increased accuracy represented by another decimal place.” British physicist J. J. Thomson: “All that was left was to alter a decimal or two in some physical constant.” American physicist Albert A. Michelson: “Our future discoveries must be looked for in the sixth place of decimals.”
:My physics professor from freshman year: "If you're ever in a room with physicists who say that the physics of Earth are done, and there's nothing else left to calculate, ask them "what about turbulence?". You'll be sure to get some dirty looks."[[Special:Contributions/108.162.246.122|108.162.246.122]] 21:08, 9 December 2021 (UTC)
--[[User:Marceluda|Marceluda]] ([[User talk:Marceluda|talk]]) 15:32, 9 December 2021 (UTC)

Talk:342: 1337: Part 2

2016-10-19T20:27:05Z

108.162.246.122:

Well, imho the reference to the master in the mountain hideaway is clearly a reference to Kill Bill, but I am not skilled enough in English to write it myself...
[[Special:Contributions/217.162.253.103|217.162.253.103]] 13:06, 6 March 2013 (UTC)
:Next time, don't be so shy! Just do the best you can and someone else can help correct it. [[User:Alpha|Alpha]] ([[User talk:Alpha|talk]]) 00:21, 7 March 2013 (UTC)

I don't see why dijkstra's algorithm would use less memory than A*. Any ideas? [[Special:Contributions/24.18.133.138|24.18.133.138]] 01:44, 13 July 2013 (UTC)
:Dijkstra's algorithm only needs to store one distance value per node, whereas A* needs at least an additional priority queue. Sometimes A* also precalculates and stores its heuristic. --[[User:Chtz|Chtz]] ([[User talk:Chtz|talk]]) 09:42, 13 July 2013 (UTC)

The mountain hideaway is a staple of Kung Fu movies. Kill Bill was effectively spoofing the genre, and so is this cartoon (rather than specifically spoofing Kill Bill). [[User:Danshoham|Mountain Hikes]] ([[User talk:Danshoham|talk]]) 04:17, 9 October 2015 (UTC)

Is that an ice pack he's holding in the first panel? [[Special:Contributions/108.162.210.232|108.162.210.232]] 23:42, 15 May 2016 (UTC)
:That's something I was wondering too. It's either an ice pack or a towel of some kind. Why would he need an ice pack / towel? Either he's sweating because he's nervous, it's an author mistake, or something offscreen happened. But... what could have happened? --[[User:JayRulesXKCD|JayRulesXKCD]] ([[User talk:JayRulesXKCD|talk]]) 11:49, 13 September 2016 (UTC)

Anybody notice how her son is Bobby Roberts, or if we're going by the Exploits of a Mom comic, Robert Roberts? [[Special:Contributions/108.162.246.122|108.162.246.122]] 20:27, 19 October 2016 (UTC)

Talk:1673: Timeline of Bicycle Design

2016-04-27T16:06:54Z

108.162.246.122: Reins?

I have deleted the entire paragraph with the Alternatively, explanation that this could be an analogue to the process of meiosis and pregnancy... It seems extremely far fetched to me... [[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 13:01, 27 April 2016 (UTC)

Seconded. This is a bizarre comic, and there will be a bizarre explanation, but that is clearly not it. [[Special:Contributions/141.101.70.181|141.101.70.181]] 13:04, 27 April 2016 (UTC)

That 1860 bike looks like the {{w|American Star Bicycle}}, but the year doesn't match. [[Special:Contributions/141.101.79.49|141.101.79.49]] 13:10, 27 April 2016 (UTC)

(Moved here from explanation:)<br> The randomness of the designs reminds me of the strange designs produced by the genetic evolution AI in the game BoxCar2D.[[Special:Contributions/141.101.80.78|141.101.80.78]] 15:05, 27 April 2016‎

This comic strongly remind me of http://boxcar2d.com/ [[User:Dorus|Dorus]] ([[User talk:Dorus|talk]]) 14:24, 27 April 2016 (UTC)

I third the above comments. It could also help explain the title text, as the 1955 panel shows a broken and failed cycle, which can happen when a detrimental mutation (like weak wheel linkages) is selected by the AI to be passed on.

Would have seconded it, only looks like I'm fourthing it, instead. Also I adjusted 1925's transcript description as the numbers were wrong. (I also suspect it's related to the stabilisation applied to the [https://postalheritage.wordpress.com/tag/pentacycle/ Pentacycle], only without visible in/out-of-page stability. (Because the third dimension doesn't exist? Well apart from 1900 that looks to be a bicycle version of the [http://www.thisvictorianlife.com/cycling.html Rudge], with a solid insert to the spoked wheel ('poor man's disc-wheel' kit?) obscuring all but the spurious over-wheel drive-chain and the rider's head.) [[Special:Contributions/141.101.98.137|141.101.98.137]] 15:09, 27 April 2016 (UTC)

Can you include the 'Alternatively,' explanation down here so I (and presumably others) don't have to wade through the page's history? We could list all sorts of far-fetched explanations, it has definitely happened on other comics.

I have a feeling that this is related to the idea that nobody can draw a bicycle. For example, [https://www.behance.net/gallery/35437979/Velocipedia this artist created 3D renderings of bicycles drawn by strangers]. [[User:Rael|Rael]] ([[User talk:Rael|talk]]) 14:51, 27 April 2016 (UTC)

Does anyone else think the 1980 bike resembles a horse-drawn carriage minus the horses? Specifically, the two long parts Megan is holding look like reins. [[Special:Contributions/108.162.246.122|108.162.246.122]] 16:06, 27 April 2016 (UTC)

1662: Jack and Jill

2016-03-30T14:01:55Z

108.162.246.122: /* Transcript */

{{comic
| number = 1662
| date = March 30, 2016
| title = Jack and Jill
| image = jack_and_jill.png
| titletext = Jill and Jack / began to frack. / The oil boosts their town. / But fractures make / the bedrock shake / and Jack came tumbling down.
}}

==Explanation==

The comic is about a nursery rhyme "[https://en.wikipedia.org/wiki/Jack_and_Jill_(nursery_rhyme) Jack and Jill]". The first verse is:

Jack and Jill went up the hill
To fetch a pail of water.
Jack fell down and broke his crown,
And Jill came tumbling after.

The comic makes fun of how it's weird that they go up a hill to fetch water, because water is usually found in valleys rather.

The title text is a parody of this first verse, connecting the idea to hydraulic fracturing (or fracking) methods for oil and gas extraction. In these methods, highly pressurized liquids are forced into a given ground stratum (or layer). With enough pressure, the stratum starts to deform and crack. This allows potential gas and oil to flow more freely. The liquid used for fracturing usually also contains materials like sand or ceramics which, once the liquid is removed, will help to maintain the newly formed cracks so as to further allow the desired free movement of oil and gas.

A common side effect of this method is that water levels and presence at the surface might be modified. In this comic, water can now be found at the top of the hill. This goes against the usual laws of hydraulics, themselves subject to the laws of gravity, which indicate that water should go down through ground cracks. Thus water is usually found at the bottom of valleys or hills. But in the comic, fracking at the bottom forces the water up, thus explaining why the kids go get water up the hill, which, as Megan points out, is messed-up hydrology.

==Transcript==
{{incomplete transcript}}

:[Jack and Jill are walking by Megan; Jack has a pail in his hand.]
:Jill: Me and Jack are going up the hill to fetch a pail of water.

:Megan: Okay, have fun!

:[beat panel]

:Megan: ... wait. What the heck is going on with the hydrology around here?

{{comic discussion}}

1662: Jack and Jill

2016-03-30T13:56:36Z

108.162.246.122:

{{comic
| number = 1662
| date = March 30, 2016
| title = Jack and Jill
| image = jack_and_jill.png
| titletext = Jill and Jack / began to frack. / The oil boosts their town. / But fractures make / the bedrock shake / and Jack came tumbling down.
}}

==Explanation==

The comic is about a nursery rhyme "[https://en.wikipedia.org/wiki/Jack_and_Jill_(nursery_rhyme) Jack and Jill]". The first verse is:

Jack and Jill went up the hill
To fetch a pail of water.
Jack fell down and broke his crown,
And Jill came tumbling after.

The comic makes fun of how it's weird that they go up a hill to fetch water, because water is usually found in valleys rather.

The title text connects the idea to hydraulic fracturing (or fracking) methods for oil and gas extraction. In these methods, highly pressurized liquids are forced into a given ground stratum (or layer). When pressure is sufficient, the stratum starts to deform and new cracks start to form. This allows potential gas and oil to flow more freely. The liquid used for fracturing usually also contains materials like sand or ceramics which, once the liquid is removed, will help to maintain the newly formed cracks so as to further allow the desired free movement of oil and gas.

A common side effect of this method is that water levels and presence at the surface might be modified. In this comic water is now to be found at the top of the hill, which goes against the usual laws of hydraulics, themselves subject to the laws of gravity, which indicate that water should go down through ground cracks. Thus water is usually found at the bottom of valleys or hills. But in this comic, probable fracking at the bottom forces the water up, thus explaining why the kids go get water up the hill, which, as Megan points out, is messed-up hydrology.

==Transcript==
{{incomplete transcript}}

Jill: Me and Jack are going up the hill to fetch a pail of water.
Megan: Okay, have fun!
Megan: ... wait. What the heck is going on with the hydrology around here?

{{comic discussion}}