explain xkcd - User contributions [en]

Talk:3046: Stromatolites

2025-02-07T22:00:23Z

172.71.160.32:

Yay, another Beret Guy appearance! '''[[User:42.book.addict|42.book.addict]][[User talk:42.book.addict|Talk to me!]]''' 03:46, 4 February 2025 (UTC)
:He's unusually sage this time. ;) --[[Special:Contributions/172.71.160.32|172.71.160.32]] 22:00, 7 February 2025 (UTC)

I'm not sure if I'm trying to remember Bloom County and the penguin (Opus) or Snoopy by Schulz because of the last panel. Shrug. Prolly both. Warm is good. [[Special:Contributions/172.70.175.208|172.70.175.208]] 06:08, 4 February 2025 (UTC)
:Add Zonker to this list? [[Special:Contributions/108.162.245.39|108.162.245.39]] 17:29, 4 February 2025 (UTC)
:: Zonker Harris, yes! [[Special:Contributions/172.70.175.106|172.70.175.106]] 18:16, 4 February 2025 (UTC)

How can anybody be related to rock formations? Stomatolites are not organisms, they are the product of organisms. [[Special:Contributions/141.101.105.88|141.101.105.88]] 08:12, 4 February 2025 (UTC)
:This might be one of Randall's weaker offerings in terms of scientific accuracy. I think that "stromatolites" as here used refers to the cyanobacterial component of stromatolites, which is the component detected in ancient fossils and is the one responsible for oxygen-evolving photosynthesis (responsible for what was perhaps the {{w|Great_Oxidation_Event|first global environmental catastrophe}} - an element of ancestry of which it might be wise not to boast). Modern stromatolites have both cyanobacteria (ancestors of plastids) and alpha-proteobacteria (ancestors of mitochondria) in their microbial mats, and it's reasonable to assume that alpha-proteobacteria were present in the fossils. So the "cousins" would be of cyanobacteria in the stromatolites, not the stromatolites themselves (in which both were, presumably, cohabiting). Beret Guy also appears to be confused about the proposed sequence of events leading to the origins of mitochondria and eukaryotic cell nuclei. [[Special:Contributions/108.162.245.39|108.162.245.39]] 17:29, 4 February 2025 (UTC)
:I've seen the surviving microbial mats in Australia referred to as "stromatolites" as well.[[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 12:39, 4 February 2025 (UTC)

I wonder if he is related to any specific dinosaurs or whether he bypassed that branch of the tree completely. 09:48, 4 February 2025 (UTC)

I think there's a joke (or at least a reference) here about the relatedness of life. All currently-known organisms are related by descent from a common ancestor, which in English makes us all cousins, of various distances. Mitochondria in plants and animals, for instance, must descend from the same bacterium-like organism that became an endosymbiont in a proto-eukaryote.[[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 12:39, 4 February 2025 (UTC)
:Since mitochondria and chloroplasts were both originally distinct organisms that were absorbed into the host cells, that makes most modern life descendants of cannibals. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 15:37, 4 February 2025 (UTC)
::By that logic, eating pretty much any food except salt (and maybe dairy?) is cannibalism. [[Special:Contributions/172.68.70.87|172.68.70.87]] 16:09, 4 February 2025 (UTC)

I immediately thought of [https://fabpedigree.com/ Fabulous Pedigree], which ''does'' include ancestry (and side-branches) going back to (and past) mitochondria, though from a quick check it doesn't seem to specifically include stromatolites. Obviously the listing has lots of (mostly implied) gaps. --[[Special:Contributions/162.158.217.72|162.158.217.72]] 13:55, 4 February 2025 (UTC)

Beret Guy is emulating Pooh-Bah in The Mikado: "I can trace my ancestry back to a protoplasmal primordial atomic globule."[[Special:Contributions/172.69.33.190|172.69.33.190]] 19:07, 4 February 2025 (UTC)NickM

I've added a bit about the length of time it would need to take to click that far back in the past. I'm sure I have got the amount out by several orders of magnitude, so I would appreciate it if anyone fancies a go at estimating how long Beret Guy would have taken. [[Special:Contributions/172.71.241.27|172.71.241.27]] 10:49, 4 February 2025 (UTC)
: [[2608: Family Reunion]] estimates about 50 billion generations to the MRCA with plants; this would have taken about a century at a speed of 15 clicks per second. Bacteria reproduce extremely fast - or at least modern ones do - which could easily add a few trillion generations (and a few thousand years of clicking) on the bacterial side of the ancestry. In other words, "thousands of years" is likely an overestimate but not ''that'' much of one. (Obviously the time becomes very feasible if Beret Guy used a site that summarized the ancestry.) --[[Special:Contributions/162.158.111.134|162.158.111.134]] 20:25, 4 February 2025 (UTC)
::Typically the way it works is you work back so far and then find a connection to a ''pre-existing'' tree, so he wouldn't need to go very far back to get to a tree that covered all modern humans, provided someone had already done the work beyond that point before him.[[Special:Contributions/172.70.91.29|172.70.91.29]] 10:27, 5 February 2025 (UTC)
:::...this would have required someone else to have (give or take a small proportion of BG's generations, due to mismatches) done the same work as BG ''and then'' the work that we're now excusing BG as having not done. Hard to know how that would happen
:::Theoretically, if the website/database was ''live'' at the point of the point of Most Recent Common Human Ancestor, that individual could establish the 'further back' (ready for BG's search to find them and latch on to it), or at least as far back as a prior MRCA that also had the website hand to pre-establish yet further back (for as many further iterations as necessary), which might even be tied in with ''how'' sufficiently(?) detailed core family tree data. But then BG's Special Powers is reliant upon finding a website that actually predates the web ('90s) and the internet ('70s), and networked databases ('60s), and programmable computers ('40s), and keyboards (let's say the 1700s), and mice (the paleocene, who would have probably prefered using {{w|Gopher (protocol)|gopher}}), that was somehow still interacted with in order to set things up ready for BG's own (more trivial) direct miracles. [[Special:Contributions/172.70.163.167|172.70.163.167]] 13:10, 5 February 2025 (UTC)
::::It would have required someone else to create it, but not necessarily by repeated clicking - they could have used some automated process to do it that would speed things up substantially. Of course, there is then a problem of where the data comes from to feed that process, but once you start worrying about that you've got a more fundamental issue than how quickly he (or anyone else) can click things.[[Special:Contributions/141.101.98.187|141.101.98.187]] 17:05, 5 February 2025 (UTC)

Six paragraphs should be four. Too much non-explanatory and otherwise pointless digression. I'm sure the people who write it don't realize how much it turns off people coming here to read an explanation. [[Special:Contributions/172.70.215.72|172.70.215.72]] 11:03, 5 February 2025 (UTC)
:Which two paragraphs? And we already have long paragraphs, but if we joined two pairs together then you'd be happy? Counting just paragraphs is not a good measure, whatever you really mean. And I guarantee that most of what you'd want to remove is only subjectively unnecessary.
:Personally, I'd like the existing six to be tightened up (somehow, yet to go through them to work out how), but each has good points in. Could you be happier with just less loquacious verbosity, but presenting the same general scope in less space? (Probably not, but depends exactly which elements are "pointless digression" in your POV...) [[Special:Contributions/172.70.163.167|172.70.163.167]] 13:10, 5 February 2025 (UTC)
:Tolkien wrote this about critique of his Lord of the Rings: "... for I find from the letters that I have received that the passages or chapters that are to some a blemish are all by others specially approved." In the absence of a polling system, how are folk to assess the significance of individual comments? One could do a Musk run through the text, roiling the explain-xkcd community and thereby creating a disturbance in the Force, without actually improving the read. The uncharacteristically poor handling of the science underlying the comic complicates efforts to achieve conciseness and clarity. [[Special:Contributions/172.71.146.32|172.71.146.32]] 14:07, 5 February 2025 (UTC)

Parody? (with an evolutionary theory). Several news sites (tabloids?) occasionally write news about people being extremely distantly related to (e. g. 17th-order cousins and above) each other. This comic takes it to the extreme case of being related to the bacteria that created stromatolites. The evolutionary theory shown in the comic is that every organism (Bacteria and Archaea s. l.) is related. [[Special:Contributions/172.70.35.190|172.70.35.190]] 07:07, 6 February 2025 (UTC)
:As already covered by a prior comic, we have (nth-)cousins all over the place. A lot of store was set by Obama being 10th cousins with Bush Jr, but also 15th cousin to Churchill and 9th cousin to ''Brad Pitt'' (with Hillary Clinton being 9th cousin to Angelina Jolie).
:But cousins is fairly 'easy' (so long as the records, or reasonable presumptions, exist), as there steadily become so many potential common ancestors by various different branches that you might easily find a fathers'-sides co-ancestry point just by having surname clues (to bridge any actual gaps in the paperwork) where a more direct mothers'-sides relationship might be lost. (That's the ''official'', ancestry, of course... Blood descent could well depart significantly from that, whether or not anyone (who 'matters') thinks/'knows' differently at the time.)
:By the same measure, you have also found the (possibly!) most recent common ancestor... You know there ''must be one'', of course, but placing them is subject to all the issues of lack of records (or misdirecting ones) giving you problems. But Beret Guy seems to think his efforts are accurate. And, knowing his expectation-based powers, he probably has. No real parody of evolution, just simplifying away the necessarily messy parts of its long-term study. [[Special:Contributions/172.70.91.11|172.70.91.11]] 14:40, 6 February 2025 (UTC)

== The [[What If? chapters|What If? article index]] project ==

Hey everyone,

I'm not sure if you noticed the banner of the site, but for the last few weeks a group of [[Talk:What If? chapters|incredibly talented editors]] have been redesigning the [[What If? chapters|'''index of ''What If?'' articles''']] from the ground up. Among other things, we've merged two huge tables, added a TON of additional info, created complex templates, and made [[What If? chapters|dozens and dozens of other improvements]]. I believe that, as a wiki, we should have a complete and detailed index of all what if? articles, [[List of all comics (full)|just like we do for the comics]], and we're getting so close to that goal! We mostly only need to add the missing explanations, improve the existing ones, and add the questions and answer summary from the books (plus other things).

We would love your help (especially if you have the first book)! We've prepared a [[What If? chapters|to-do list]] at the top of the page, containing everything that needs to be done, if you're interested. --[[User:FaviFake|FaviFake]] ([[User talk:FaviFake|talk]]) 07:00, 4 February 2025 (UTC)

3026: Linear Sort

2024-12-20T19:17:36Z

172.71.160.32: Better explanation of the hoax O(n) algorithm

{{comic
| number = 3026
| date = December 18, 2024
| title = Linear Sort
| image = linear_sort_2x.png
| imagesize = 385x181px
| noexpand = true
| titletext = The best case is O(n), and the worst case is that someone checks why.
}}

==Explanation==
{{incomplete|Created in Θ(N) TIME by an iterative Insertion Sorter working on a multidimensional array - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

A common task to have computers do is to sort a list, such as from A to Z or from the smallest to the largest number. There are dozens of algorithms created to accomplish this task through the years, from simple to complex, each with its own merits with regard to how easiness of implementation, memory usage, and efficiency; in order to understand the last one, computer scientists created {{w|Big O Notation}}. There are two aspects of Big O notation to know:

1. It is ''asymptotic''; meaning that it simply expresses the base relation between the size of the list and the time needed to sort. O(2''n'') is written simply as O(''n''), because Big O is more concerned about indicating the sort time scaling linearly rather than accurately giving you a formula to calculate how long it'll take. Likewise, O(2''n'' + ''n''2) might be written as O(2''n'') because the value of ''n''2 would eventually become small enough (relative to 2''n'') to be rounded off.

2.Big O notation is only an average estimation. The actual figure depends on the hardware, software, and the initial state of the list - consider if you needed to sort a pile of books by title you might luck to find most books are already in the correct position and only need to move one or two, or they might be hopelessly jumbled up and necessitate moving most, even all of them. Big O notation is mainly used to examine various methods to accomplish the same task, running on the same hardware, rather than being real-world benchmarks.

A few common Big O notations are listed below, from smallest to largest:
<ul><li>O(1) - Constant time, which means the sorting will always take X seconds no matter how big the data is</li>
<li>O(''n'') - Linear time, which means the execution time grows in direct proportion to the size of the data</li>
<li>O(''n'' log(''n'')) - The execution time grows proportionally to ''n'' * the {{w|logarithm}} of ''n''. For small lists, this value would be smaller than O(n) (meaning it'll take less time), but as the lists grow it will generally take more time (again, on average).</li>
<li>O(''n''2) - Quadratic time, meaning the execution time grows proportionally to the ''square'' of the size of the data.</li></ul>

As one can image in most contexts one would wish for sorting to be done as fast as possible, so O(1) is better than O(n), which is in turn better than O(n*log(n)) etc (at least assuming your lists are relatively small). The code in the comic describes a 'linear' sort that first sorts the list using {{w|merge sort}}, which is known to take time O(''n'' log(''n'')), and then `sleep()`s (pauses with no activity) for an amount of time equal to subtracting the time taken for the sort from the number of elements multiplied by 1 million (1e6) seconds. Here the joke is that, rather than creating an algorithm that actually takes O(n) time it simply disguises an algorithm that takes O(n*log(n)) and makes it appear to be O(n). The runtime is much longer than the mergesort, but it increases linear with the length of the list. So it appears to be O(n). This is obviously unideal as waiting around doing nothing is the opposite of optimization.

This joke is carried on by the title text, which refers to the {{w|Best, worst and average case|best and worst case}} of a sort, which are additional measures of its runtime to describe the shortest and longest potential times. A more optimal sort may decide how much of a list needs to be passed over again after its first pass of shuffling elements around; scanning a pre-sorted list (and deducing that it has no more checking to do) could mean that no more effort is needed, resulting in a best case of O(''n''). Depending upon the algorithm, presenting a list that is in an ordering that happens to challenge it the most (such as exactly reversed) may mean even an 'average O(''n'' log ''n'')' process would have to exceed this, resulting in a worst-case number of operations that may be O(''n2''). It can be very useful to know that a given sorting method ''may'' take the average order of time, but have the possibility of a much shorter ''or'' longer runtime... especially when the method is expected to be [[1185: Ineffective Sorts|far, far worse than others]], where only particular and more idealistic input lets it approach the more satisfyingly fast average/best responses.

By forcing all practical searches to take O(''n'') time, regardless of how otherwise identical data is presorted, the best case (and worst case, for that matter) will also be O(''n''). The last part of the text then plays on another meaning of best case and worst case, as best- and {{w|worst-case scenario}}s for a situation, by saying that the worst outcome for the code's author is when someone decides to investigate the code (perhaps owing to its absurd runtime, or else just justifiably skeptical of the declared optimality), whereupon that investigator will discover the deception and ruin the author's reputation.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[The panel shows five lines of code:]
:function LinearSort(list):
::StartTime=Time()
::MergeSort(list)
::Sleep(1e6*length(list)-(Time()-StartTime))
::return

:[Caption below the panel:]
:How to sort a list in linear time

{{comic discussion}}

[[Category:Programming]]

Talk:2935: Ocean Loop

2024-05-21T14:29:58Z

172.71.160.32: Aqualoop

The 'standard' and '2x' sized images had unexpected sizes, so a Trivia section has been automatically generated, and an imagesize parameter has been added (at half size) to render the image consistently with other comics on this website. --[[User:TheusafBOT|TheusafBOT]] ([[User talk:TheusafBOT|talk]]) 20:47, 20 May 2024 (UTC)

Is there anyway to get notifications when a new comic comes out? I'm always late to these 21:27, 20 May 2024 (UTC)Jush
:I believe that there may be a Twitter (or X, or Xwitter, whatever we're calling it out) announcement direct from Randall's account, but I don't use that myself. And, like me, you were here ''right as it came out'', more or less, so so don't worry too much. You ''could'' write your own BOT-like poller (various ways, but do at least considerately throttle it back to checking perbaps no more frequently than every 15 minutes, 'cos too many people doing that would be 'problematical'), if you can't find a push-notifying service that does most of the hard work for you (and a whole host of other subscribers). [[Special:Contributions/172.70.85.241|172.70.85.241]] 22:23, 20 May 2024 (UTC)
:You can use the RSS feed: https://xkcd.com/rss.xml [[User:Val|Val]] ([[User talk:Val|talk]]) 04:07, 21 May 2024 (UTC)

Happy Victoria day to anyone else in Canada! [[Special:Contributions/162.158.146.235|162.158.146.235]] 21:39, 20 May 2024 (UTC)

Due to not being told about any Edit Conflict, I managed to co-edit the initial explanatuon with A.N.Other (sorry, haven't checked who, probably the first major editor in the page-history). I've put the most useful bit (IMO) of their article into mine, but some of it seemed wrong. Or at least not right.
*"because of the size and speed of a cruise ship, the ship likely wouldn't make it around the loop without falling off" - well, given the mass of water nicely holding itself to the loop, a ship floating around in it at the same speed would be holding itself to the loop quite nicely (moreso, perhaps, with its CoG taking a tighter loop than the fluid-loop).
**Of course, it could be slower, but that would mean fighting the current. Whatever huge velocity the water is going, you'd have to be capable of going full-reverse at ''significant'' speed to overcome that,
***Well, you could be ''just'' less than the ''just'' more than fast-enough water, but it's probably significantly faster than loop-speed, or a lot of edge-surface water would shed out of the topmost loop-trough due to fluidic friction against the trough itself.
***And there's the acceleration needed to match the fluid flow-rate, but that causes problems before 'falling off' is an issue. Imagine suddenly finding yourself going hundreds (thousands?) of knots sternwards in still water. Probably what it'd feel like, before even getting to the tilt (by which time, any ship that had survived is probably now close to water-speed).
*"Second even if they managed to make it through without falling, many of the passangers would abtain extreme injuries and/or likely fall off the ship all together (unlike {{w|rollercoasters}} the passengers aren't strapped down)" - If you experience negative Gs in a rollercoaster, it's not a true loop (just an awkward inversion). You should normally always stay at positive Gs, albeit at somewhere within 0<Gs<1 (which ''feels'' like negative, but is just short of weightlessness). Being strapped in is still important, but mostly for forces lateral to "local down" for where you are on the ride.
**...or, of course, if the ride malfunctions and leaves you stationary and inverted. Which happens, but that's not at all intended in most situations. There'd be no way an 'otherwise normal' flume-loop would do that, though refering back to the need of your ship to experience initial acceleration before it even hits the loop (and final deceleration once it exits it).
*"Third, because of the way the loop's designed, several hundreds (if not thousands) of tons of water is being launched onto the top of the cruise ship at a high speed. Needless to say, this would not only likely capsize the ship, but would also flatten any passenger on the deck." - The sudden undersea current is going to be a problem, but it's not going to be directed over the ship (save ''completely'' over the ship, in the loop far above).
**What you'll have is the turbulent local sea conditions. There'd be a 'standing wave-trough' in front of the point the jet of water is shown to emerge, itself probably a catastrophic problem for a ship, even an ocean-going one built in expectation of occasionally meeting {{w|rogue waves}}) and all the problems involved in traversing such rough seas. If your vessel can survive that (without spinning sideways and hitting the flume-trough, or breaking its back due to the extremely uneven and changing buoyancy along its length) then it's probably going to survive the much smaller amount of water that splashes 'over' its upper superstructure, compared to whatever relative mastrom of flow there will be passing under/against its (nominally) below-waterline hull.
I don't know how much 'reality' Randall has invested in this premise (I presume little, given the lack of pressure-trough in the 'still' water just short of the jet-emergence, nor any distortion in the sea surface wherever the jet originally sucked its water in from), but a lot of the issues of the looping-the-loop "What if" train will be the prime factors, plus maintaining general control (in river navigation, going downstream, between bridge piers, you really have to power your vessel forward, faster than the river itself, or risk losing yaw discipline on your craft). All the rest is icing on the cake of improbability. [[Special:Contributions/172.70.85.241|172.70.85.241]] 22:23, 20 May 2024 (UTC)
:It's a comic drawing after all, it's meant to illustrate the concept but leave the actual reality to our imagination. Conceptually it seems obvious to me that if the ship actually makes it through the loop, it exits fairly smoothly (class 2 or class 3 white water rafting).[[Special:Contributions/162.158.146.52|162.158.146.52]]
:"...wherever the jet originally sucked its water in from..." - from the mains, obviously.[[Special:Contributions/172.69.194.204|172.69.194.204]] 11:05, 21 May 2024 (UTC)

The current paragraph on the title text seems off-base. It seems pretty clear to me that Randall had the idea, managed to get the loop constructed, persuaded the ship to sail to the vicinity (unless it was constructed on a previously planned route), and was attempting to persuade them to enter it ''before'' anyone realised it was a bad idea and objected. He then tried toorganise the passenger poll, and they shut that down too, and fired him. The suggestion that someone else randomly built the thing, separately from him trying to persuade them to use it, doesn't really make any sense.[[Special:Contributions/172.70.90.48|172.70.90.48]] 11:24, 21 May 2024 (UTC)

As a ballpark, spherical cow, estimate: To complete the loop, the centripetal force at the top of the loop has to equal the gravitational force of the ship. Centripetal force is mv^2/r, and gravitational force is mg, so we have v_top^2/r = g, v_top = sqrt(gr). At the top of the loop, the height is 2r, which means you have potential energy 2mgr, and kinetic energy 1/2 mv_top^2 = 1/2 mgr. Thus, at the bottom of the loop, you need kinetic energy 2mgr + 1/2 mgr = 5/2 mgr. This gives us the velocity at the bottom of the loop, 1/2 mv_bot^2 = 5/2 mgr, v_bot = sqrt(5gr). Call the cruise ship 300 m long, the diameter of the loop appears to be about 3 ship lengths, so r = 450 m. So the ship has to enter the loop at 150 m/s, 540 km/h, 335 mph. That's about Mach 0.45, which is probably the first time a cruise ship speed has ever been described with a Mach number. [[Special:Contributions/172.70.135.75|172.70.135.75]] 13:03, 21 May 2024 (UTC)

There are human scaled water slide loopings, but they start by having the human drop vertically and then "only" loop up with ~45° inclination: {{w|AquaLoop}}. This probably would not easily scale to cruise ship sizes. Also starting the looping horizontally and going upwards may be a challenge to implement. --[[Special:Contributions/172.71.160.32|172.71.160.32]] 14:29, 21 May 2024 (UTC)

Talk:2927: Alphabetical Cartogram

2024-05-02T14:39:07Z

172.71.160.32:

replaced incorrect explanation [[Special:Contributions/172.70.111.45|172.70.111.45]] 17:17, 1 May 2024 (UTC)
Is it me or is Hawaii strangely bigger than california. {{unsigned|172.70.100.40}}
:I think he's only counting the land area. The area between the islands may be creating an illusion that Hawaii is bigger. It's hard to tell just by looking, does anyone have the tech to measure this? P.S. remember to sign... [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 14:11, 1 May 2024 (UTC)

Im just wondering why Maine is still so big.... [[User:JushJosh|JushJosh]] ([[User talk:JushJosh|talk]]) 13:22, 1 May 2024 (UTC)Jush
:I know, right? That's what made me think it wasn't just a simple alphabetical listing. That, and Hawaii is bigger than Alaska, despite the fact that Alaska is substantially higher on the list. In fact, it even appears that Alaska is smaller than Maine! How did Randall decide on the sizes??? [[User:Pie Guy|Pie Guy]] ([[User talk:Pie Guy|talk]]) 16:01, 1 May 2024 (UTC)

The sad part is that Rhode Island grew. [[Special:Contributions/172.71.31.139|172.71.31.139]] 14:01, 1 May 2024 (UTC)

I believe it is some sort of ranking rather than swapping sizes as the chart suggests, as South Carolina appears to be smaller than normal (?) [[User:Primmy|Primmy]] ([[User talk:Primmy|talk]]) 14:56, 1 May 2024 (UTC)

Poor Utah :( [[User:Z1mp0st0rz|If you click on this you will get a fun surprise]] ([[User talk:Z1mp0st0rz|talk]]) 15:15, 1 May 2024 (UTC)

I believe the first paragraph is incorrect. I did a full comparison, and Texas shrank the most (dropping 41 places from size ranking to alphabetical ranking), while Connecticut as well as Delaware grew the most (each rising 41 places between the lists). [[Special:Contributions/172.71.255.28|172.71.255.28]] 15:40, 1 May 2024 (UTC)

This map gives a lot more land to Mexico. [[User:Weslar|Weslar]] ([[User talk:Weslar|talk]]) 16:31, 1 May 2024 (UTC)
:Mexico is not represented at all in the map. And all states are much smaller than in reality (unless you have a very big monitor, c.f. [[2911]]) --[[Special:Contributions/172.71.160.32|172.71.160.32]] 12:30, 2 May 2024 (UTC)

UNFORTUNATELY it seems that there are many errors in the actual relationship of sizes. I did a quick area take off of each state. These units are in miles using the real width of Colorado (since it is about the same place in the list) as the scale reference. https://imgur.com/a/hKIVjRZ. you can see immediately that Delaware and Alaska and Iowa are incorrect in the order.

Ignoring the Errors in the map and Assuming We are keeping the total area of the US the same and scaling the new map based on this total... then Alaska loses the most land area ( approx 510,000 mi) and Alabama gains the most Land area (156,000 mi). Looking at which state gained or lost the largest percentage of its land area shows that Minnesota is the least affected at only 4.6% or 4,200 mi and Wyoming is the most affected losing 98% of its land area or 95,000 miles.[[Special:Contributions/162.158.41.56|162.158.41.56]]

As a Wyomingite, I can't complain. We're still bigger than our population justifies. (fun fact, we get two whole senators despite lacking the population to actually justify a single house member)[[Special:Contributions/172.68.34.59|172.68.34.59]] 17:08, 1 May 2024 (UTC)

Alaska is STILL disproportionally small. [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 17:24, 1 May 2024 (UTC)

Utah is way too big (should be after Texas) and Idaho is too small (should be bigger than the Ms)

Why the hell is Massachusetts so BIG?! [[User:Psychoticpotato|Psychoticpotato]] ([[User talk:Psychoticpotato|talk]]) 13:01, 2 May 2024 (UTC)
:To account for all its Mass. [[Special:Contributions/172.71.242.175|172.71.242.175]] 13:51, 2 May 2024 (UTC)

I went further and measured the exact sizes of each state to the pixel: https://imgur.com/a/d6ruHvs really nerd sniped myself lol. The post includes excel screenshots as well as text, and the image I used at the bottom. Will explain methodology if anyone wants. Obviously all these discrepancies are due to the fact that the states actually have to fit together for the joke-map to work. [[User:Paintadot|Paintadot]] ([[User talk:Paintadot|talk]]) 13:48, 2 May 2024 (UTC)
:Having the pixel area for each state in the explanation would be really nice! Do you count the "border pixels" (or maybe half of them) to the pixel area? (not sure if that would be sufficient to have Alaska stay atop of Arizona ...) --[[Special:Contributions/172.71.160.32|172.71.160.32]] 14:39, 2 May 2024 (UTC)

Talk:2927: Alphabetical Cartogram

2024-05-02T12:30:50Z

172.71.160.32: Re: Mexico

Talk:2926: Doppler Effect

2024-04-30T09:36:10Z

172.71.160.32: Blue lights in Europe

Honestly, this is one of my favorite ones yet, [[User:Apollo11|Apollo11]] ([[User talk:Apollo11|talk]]) 18:21, 29 April 2024 (UTC)
:I'm not always a big fan of Miss Lenhart comics, but I agree this one is good. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 18:39, 29 April 2024 (UTC)
I think there might be some confusion in the explanation. It suggests that red shift occurs because of space expansion, not because of relative motion between the light source and observer. My understanding is that there IS relative motion between the light source and observer BECAUSE of expanding space. [[Special:Contributions/172.68.22.151|172.68.22.151]] 19:54, 29 April 2024 (UTC)
:Edit - There appears to be a "just" in there that I missed, changing the meaning of the sentence somewhat. Never mind. [[Special:Contributions/172.68.22.151|172.68.22.151]] 19:58, 29 April 2024 (UTC)
::My understanding is that there is relative motion between the galaxies, but there is also redshift caused by the expansion of space while the light was traveling, which would occur even if the galaxies were at rest. And IIUC for most galaxies this is the dominant effect -- the Doppler shift caused by the motion of galaxies when the light was emitted is small, but the cosmological redshift caused by the light traveling for a long time is large. [[User:Vyzen|Vyzen]] ([[User talk:Vyzen|talk]]) 21:54, 29 April 2024 (UTC)
The bit about the Doppler effect being similar to a bullet fired from a moving car is simply incorrect. That's vector addition of velocities. Sound traveling from a source is going to travel at the speed of sound in the medium, and the only addition of velocities would be to the extent that the car is moving the air around it. Also, the Doppler effect doesn't make sounds louder, that's simply a function of the distance between you and the source changing, independent of velocity. Edited the text accordingly. [[Special:Contributions/172.70.42.213|172.70.42.213]] 20:00, 29 April 2024 (UTC)
:Although firing an automatic firearm from a moving car can make a pretty decent analogy, as the bullets will pass a person the car is moving toward more frequently or a person the car is moving away from less frequently. Though I think drive-by shootings are probably not the ideal metaphor to use in classrooms. Perhaps a nerf gun? [[Special:Contributions/172.69.246.148|172.69.246.148]] 20:38, 29 April 2024 (UTC)
This comic seems to be poor nerd sniping for explainxkcd to get into a long explanation why galaxies are red ... --[[Special:Contributions/172.70.247.172|172.70.247.172]] 20:08, 29 April 2024 (UTC)

In the UK, the primary emergency-vehicle (police, ambulance/paramedic, fire, coastguard, anything else {{w|Emergency vehicle equipment in the United Kingdom|similarly official}}; for road/off-road/air/water vehicles of all kinds) flashing light tends to be blue. There may be alternating reds too, according to vintage, but currently blue lights are the main feature (and 'battenburgs', on marked vehicles, according to the nature of the service involved). Non-emergency vehicles' 'beacons' would be amber, on anything underspeed/stopped/extraordinary on the carriageway (road-sweepers, flatbed car-recovery, exceptional load carriers/escorts) and I think green and red flashers are common for construction site traffic. Interestingly, the other day I saw a police car ''and'' an unmarked response car (going to the same incident, both flashing their blues), three ambulances (none obviously going to same incident, and only two with blues) and a fire-engine (not flashing, probably going back to base). Only one of them (an ambulance) was blaring its respective siren, though. I believe emergency drivers are required to use them sparingly/judiciously, rather than just put the blues'n'twos on and barge through. [[Special:Contributions/172.70.90.172|172.70.90.172]] 21:06, 29 April 2024 (UTC)
:Blue lights are actually common in most of Europe: https://en.wikipedia.org/wiki/Emergency_vehicle_lighting#Usage_by_country. The light of emergency vehicles is technically also effected by the Doppler Effect, though this is barely measurable at typical driving speeds. --[[Special:Contributions/172.71.160.32|172.71.160.32]] 09:36, 30 April 2024 (UTC)

It appears to be sheer coincidence that sirens were relevant to the discussion, as Miss Lenhart does not actually seem to know that the same phenomenon is at work. --[[Special:Contributions/172.70.211.129|172.70.211.129]] 22:04, 29 April 2024 (UTC)

I’m an EMT and can explain the button that makes it go PEW PEW! The siren has quite a few different settings with different noise patterns. The noise patterns are chosen based on the surroundings. The default is a T1, the least obtrusive. You use that one on long straight roads. Coming up to an intersection, you would switch to T2, which is more noticeable and lets them know you’re close to the intersection before they can see you. Once you’re crossing the intersection, you switch to T3, the loudest and most irritating patterns, so the chance of someone not noticing you and causing an accident is lowest. There are a couple different patterns for each tier. The sirens are controlled by either dials or buttons (and some touchscreens that I hate) and there’s also a button to make the siren go off at a set tone or pattern for as long as you hold it down. [[User:Lathgaertha|Lathgaertha]] ([[User talk:Lathgaertha|talk]]) 22:50, 29 April 2024 (UTC)

: The three tiers are described in this video: https://www.youtube.com/watch?v=salqpgFuOZA. And the sounds can be heard on this video: https://www.youtube.com/watch?v=QFj0q37uvxo. [[User:Orion205|Orion205]] ([[User talk:Orion205|talk]]) 01:20, 30 April 2024 (UTC)

re: "Pew pew" still unexplained. Note that Miss Lenhart actually says "pyeew" not "pew". It's most likely not a reference to shooting, but to a siren signal that (to my knowledge) is particular to US ambulances. Sound effect in question at ~0:18 [https://www.youtube.com/watch?v=s5bwBS27A1g here]. [[Special:Contributions/172.70.46.241|172.70.46.241]] 07:52, 30 April 2024 (UTC)