explain xkcd - User contributions [en]

Talk:705: Devotion to Duty

2025-02-18T19:57:09Z

162.158.167.192:

This is very clearly a Die Hard parody. {{unsigned|‎70.12.4.193}}
:Indubitably --[[User:JSekula71|JSekula71]] ([[User talk:JSekula71|talk]]) 23:36, 9 June 2013 (UTC)

Oh man. This needs some reworking. --[[User:Quicksilver|Quicksilver]] ([[User talk:Quicksilver|talk]]) 03:10, 20 August 2013 (UTC)
: This entire entry has to be a troll... We may need an ExplainExplainxkcd for those who don't get it. [[Special:Contributions/108.162.249.155|108.162.249.155]] 05:15, 9 March 2016 (UTC)

[[Special:Contributions/108.162.250.203|108.162.250.203]] 10:33, 26 April 2014 (UTC) In Die Hard, the terrorists used a chainsaw to cut the telephone trunk cables. Try repairing that damage.
:Never underestimate the dedication of a truly devoted sysadmin! -Pennpenn [[Special:Contributions/108.162.250.162|108.162.250.162]] 04:57, 23 June 2015 (UTC)

The title text is highlighting the absurdity of the sysadmin's devotion to duty by contrasting the forces of darkness (very serious) against a blog describing the daily activities of your cat (trivial). --[[User:Bedunkel|-BD]] ([[User talk:Bedunkel|talk]]) 07:36, 17 November 2014 (UTC)

Why are there so many parentheses in the explanation? I think that needs to get fixed. [[User:Vince7778|Vince7778]] ([[User talk:Vince7778|talk]]) 23:09, 17 January 2017 (UTC)
:Yeah, it's kind of ridiculous. [[User:625571b7-aa66-4f98-ac5c-92464cfb4ed8|625571b7-aa66-4f98-ac5c-92464cfb4ed8]] ([[User talk:625571b7-aa66-4f98-ac5c-92464cfb4ed8|talk]]) 05:15, 20 March 2017 (UTC)

It is 2024 - Where can I get the T-Shrt? {{unsigned ip|172.70.247.171|14:39, 21 May 2024}}
:The XKCD store was [[Store|shut down]] years ago - [[Special:Contributions/162.158.167.192|162.158.167.192]] 19:57, 18 February 2025 (UTC)

2861: X Value

2025-02-13T09:49:33Z

162.158.167.192: /* Explanation */

{{comic
| number = 2861
| date = November 29, 2023
| title = X Value
| image = x_value_2x.png
| imagesize = 291x192px
| noexpand = true
| titletext = The value of n is still unknown, but new results constrain it to fall between 8 and 10^500, ruling out popular 'n=1' and 'n=2' theories.
}}

==Explanation==
In algebra, a {{w|Variable (mathematics)|variable}} is any symbol used to represent a number that has not been determined or chosen. The most familiar algebraic variable is ''x'' (the unknown input), with ''y'' often being the yet-to-be-determined output (its value being dependent on ''x''). According to the comic, the value of ''x'' has finally been found, being 4.1083. The joke is that a general-purpose variable, which may take different values in different scenarios, turns out to have a specific value, as though it were a constant. Constants in mathematics and other scientific fields are also often represented by a single symbol - some of the most well-known are {{w|Pi|''π''}} (3.14159...), ''e'' ({{w|E (mathematical constant)|Euler's number}}, 2.71828...), ''i'' (an {{w|Imaginary unit}}, where i2 = -1), and ''c'' (the {{w|speed of light}} in a vacuum, 299,792,458 m/s (670,616,629 mph, 1,079,252,848.8 km/h, 1.8026x1012 {{w|FFF system|fur/ftn}})).

The specific number 4.1083 does not have any notable significance or special role in the contexts of physics, chemistry, finance, astronomy or cryptography. This number to 3 decimal places, 4.108, was referenced previously in comic [[899: Number Line]].

The '''title text''' declares the value of ''n'' is unknown. ''n'' is often used as an unknown/undetermined ''integer'' value. In {{w|Sampling (statistics)|statistics}}, it might be used to specify the size of a sample. For example, a list where ''n = 50'' would mean the list contains 50 data points, for which that number of iterations or a larger number of cross-comparisons might be expected.

According to the title text, however, the value of ''n'' ''has'' been narrowed down to somewhere between 8 and 10500, or one hundred quinsexagintacentillion. This narrowing-down isn't particularly narrow, although it is perhaps quite specific compared to the 'pre-narrowing' possibilities of being absolutely any finite value at all.

The title text also says that this narrowing has ruled out the (usually) simplest values of 1 or 2. In mathematical problems involving iterating over multiple inputs of a function, or functions where the input is a list of variable size, the variable n is used to represent either the current iteration's input or the length of the input list. In both cases the inputs "n=1" and "n=2" are used as examples to demonstrate the function, to let the reader wrap their head around the basics of the function. The title text is spoofing the usage of "n=1" and "n=2" as if they were the leading theories for the constant value of n, and that these theories have been debunked by supposedly proving that n's minimum value is 8.

==Transcript==
:[A math formula is circled.]
:<big><big>x = 4.1083</big></big>

:[Caption below the panel:]
: Big math news: They finally figured out the value of x.

{{comic discussion}}

[[Category:Math]]

3036: Chess Zoo

2025-01-10T18:46:33Z

162.158.167.192: /* Explanation */

{{comic
| number = 3036
| date = January 10, 2025
| title = Chess Zoo
| image = chess_zoo_2x.png
| imagesize = 740x1221px
| noexpand = true
| titletext = The zoo takes special care to keep kings separated from opposite-color pieces as part of their conservation program to prevent mating in captivity.
}}

==Explanation==
{{incomplete|Created by a PAWN PROMOTED TO A BOT - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

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

{{comic discussion}}

Talk:3024: METAR

2024-12-16T17:53:12Z

162.158.167.192:

OMG RANDALL ADDED AN AO3 REFERENCE '''[[User:42.book.addict|42.book.addict]][[User talk:42.book.addict|Talk to me!]]''' 19:43, 13 December 2024 (UTC)
:must've been reading the fic of bill [[User:CalibansCreations|'''Caliban''']] ([[User talk:CalibansCreations|talk]]) 21:04, 13 December 2024 (UTC)
I love the things I learn from these things[[User:Rustykid52|Rustykid52]] ([[User talk:Rustykid52|talk]]) 19:48, 13 December 2024 (UTC)

Was the explanation of wind speed written by a European? The punctuation after "18" is a comma, not a period, so they it means over 18 thousand knots. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 19:59, 13 December 2024 (UTC)
: Yes, it was. I'm sorry. [[User:Janfred|Janfred]] ([[User talk:Janfred|talk]])
: If windspeed interpreted at "european style", i.e. 18 and 35/1000 knots, it s still funny, beacouse such precision of wind speed measurement is 1] unreachable (variability at space & time is several horders higher), 2] useless (fraction of knot make no difference for pilots). ([[HonzaM])

"38.08 inches of mercury" seems a very high pressure, even for a station that is well below sea level. (1290 hPa Pressure around the dead sea is typically 1060hPa).. Is that physically realistic, or is it part of the joke? I know funnel clouds, freezing and volcanic ash in the same location are unlikely outside of the apocalypse, but can be justified by the rule of funny. [[Special:Contributions/172.70.160.135|172.70.160.135]] 20:11, 13 December 2024 (UTC)
:Indeed, 31.80 is the reference high limit. Still, is Randall a pilot? The structure of a METAR is horribly familiar to us pilots but pretty much a blank stare to anyone else. [[Special:Contributions/172.68.245.25|172.68.245.25]] 21:03, 13 December 2024 (UTC)
:Feeding it into a [https://www.weather.gov/epz/wxcalc_pressurealtitude calculator] gives an altitude of -2080m (-6825'). So it's entirely reasonable as long as your weather station is in a deep mine. [[User:BunsenH|BunsenH]] ([[User talk:BunsenH|talk]]) 21:08, 13 December 2024 (UTC)
:: But isn't the value always put in reference to MSL? I.e. I'm at an airport at 1000ft, the pressure reads 977 hPa, but I'll put 1013 hPa in the METAR. (QNH in METAR vs QFE at the station) [[User:Janfred|Janfred]] ([[User talk:Janfred|talk]]) 21:14, 13 December 2024 (UTC)
::: There may be various complicated pressure differences from the tornado having dumped a load of possibly Iclandic pyroclastic tephra upon the station. [[Special:Contributions/141.101.98.181|141.101.98.181]] 21:36, 13 December 2024 (UTC)
:"outside of the apocalypse" - we are talking about NYC :P [[Special:Contributions/172.69.64.171|172.69.64.171]] 00:04, 14 December 2024 (UTC)
:: With a Bostonian leading the discussion 👹 [[Special:Contributions/162.158.42.157|162.158.42.157]] 16:51, 14 December 2024 (UTC)
:The difference between the altimeter setting and the SLP is also pretty concerning. My understanding (which is based only on a few minutes of googling, not any actual experience) is that one does not correct for temperature while the other does, based on a 12 hour average. So maybe the high value is due to crazy temperatures? Haven't done any calculations, but it would fit the apocalyptic scenario. [[Special:Contributions/172.70.247.9|172.70.247.9]] 08:40, 14 December 2024 (UTC)
::That sounds about right for the weather station {{w|Belvedere Castle|located}} at the ZIP code [[1245: 10-Day Forecast|-10021]]... [[Special:Contributions/172.70.91.11|172.70.91.11]] 09:37, 14 December 2024 (UTC)
::Your understanding is correct. Both QNH (altimeter setting) and SLP are "pressure reduced to sea level." But QNH assumes standard atmosphere while SLP attempts to use actual weather conditions. It might be just a temperature correction or it might be more.

Damn, Randall says you got No Bitches.[[User:Xurkitree10|Xurkitree10]] ([[User talk:Xurkitree10|talk]]) 06:20, 14 December 2024 (UTC)
:Alright, who here on this wiki lacks significant others? (I personally have zero (0) maidens) [[User:CalibansCreations|'''Caliban''']] ([[User talk:CalibansCreations|talk]]) 19:51, 15 December 2024 (UTC)
:By "observer", the report means the person who's observed the weather and/or data and created the report, not the person who's observing the report or the comic page. [[User:BunsenH|BunsenH]] ([[User talk:BunsenH|talk]]) 20:42, 15 December 2024 (UTC)
llama-3.1-405b-instruct (poor context, likely contains mistakes):
<blockquote>
New York, Central Park: 25th of the month, 16:00 UTC (11:00 am local time): Wind from the south at 35 knots (about 40 mph), with gusts up to 45 knots (about 52 mph): 6 statute miles visibility: In the vicinity, a funnel cloud and freezing volcanic ash: Heavy blue precipitation: No significant change in weather expected: Lightning overhead: Altimeter at 38.08 inches of mercury (about 1022.8 hPa): Precipitation discriminator present: Sea-level pressure at 1013.0 hPa (30.00 inHg, but note that this value is not explicitly stated in the METAR report, and the 'SPL130' code is not a standard way to report sea-level pressure).

...

I should have mentioned that the codes "+BLUP" are not standard METAR codes.

METAR is specified by the International Civil Aviation Organization (ICAO) in the document "Annex 3 to the Convention on International Civil Aviation: Meteorological Service for International Air Navigation". This document defines the standard format and codes used in METAR reports.

In the United States, the Federal Aviation Administration (FAA) also publishes guidelines for METAR reporting in the document "Aviation Weather Services Advisory Circular" (AC 00-45).

The World Meteorological Organization (WMO) also publishes guidelines for METAR reporting in the document "Manual on Codes" (WMO-No. 306).

These documents define the standard codes and formats used in METAR reports, but they do not include codes like "+BLUP", which are likely used in a humorous or fictional context.

...

With this transcription, I can see that the main difference is in the "SPL" code, which is now transcribed as "SLP". This makes more sense, as "SLP" is a standard METAR code for "sea-level pressure".

Here's the updated translation:

"New York, Central Park: 25th of the month, 16:00 UTC (11:00 am local time): Wind from the south at 35 knots (about 40 mph), with gusts up to 45 knots (about 52 mph): 6 statute miles visibility: In the vicinity, a funnel cloud and freezing volcanic ash: Heavy blowing unknown precipitation: No significant change in weather expected: Lightning overhead: Altimeter at 38.08 inches of mercury (about 1022.8 hPa): Precipitation discriminator present: Sea-level pressure at 1013.0 hPa (30.00 inHg)."

...

For example, let's imagine a scenario where a massive volcanic eruption has occurred in the vicinity of New York City, causing a massive ash cloud to blanket the area. The eruption is so powerful that it's creating a rare phenomenon known as "{{w|volcanic lightning}}," which is causing the lightning overhead.

Meanwhile, the ash cloud is interacting with a severe thunderstorm system, causing the formation of a funnel cloud in the vicinity of Central Park. The winds are so strong that they're blowing the ash and precipitation around, creating a situation where the precipitation discriminator is unable to accurately determine the type of precipitation.

In this scenario, the freezing volcanic ash could be a result of the ash cloud interacting with the cold air aloft, causing the ash particles to freeze into small ice crystals.

The heavy blowing unknown precipitation could be a result of the intense winds blowing the ash and precipitation around, making it difficult to determine the exact type of precipitation.

In this highly unlikely and extreme scenario, the METAR report could be more accurate. However, it's worth noting that even in this scenario, the report is still pushing the limits of what's physically possible in terms of weather phenomena.

So, while it's possible to imagine a scenario where the METAR report is more accurate, it's still a highly unlikely and extreme situation that's not representative of typical weather conditions.
</blockquote> [[Special:Contributions/172.68.26.24|172.68.26.24]] 01:40, 15 December 2024 (UTC)

A 24h-clock is a am-by-default clock. If there is a number of 1-11 it's AM by default. 12-23 tell you it's not am but pm. --[[Special:Contributions/172.69.109.92|172.69.109.92]] 14:55, 16 December 2024 (UTC)

2451: AI Methodology

2021-04-17T11:52:12Z

162.158.167.192: /* Explanation */

{{comic
| number = 2451
| date = April 16, 2021
| title = AI Methodology
| image = ai_methodology.png
| titletext = We've learned that weird spacing and diacritics in the methodology description are apparently the key to good research; luckily, we've developed an AI tool to help us figure out where to add them.
}}

==Explanation==
{{incomplete|Created by a BOT. TRAINED BY AN ADVERSARIAL AI. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

The joke in this comic is that the classifier sucks.

This comic shows Cueball giving a presentation of some description. He is reassuring his audience of the validity of his research's methodology, which he says is "AI-based". There are many issues that can arise from an AI-based methodology, such as lingering influence from its training data or a bad algorithm reducing the quality of the investigation.

Cueball seeks to reassure his audience by quantifying the quality of his methodology. He does this by creating yet another AI to rank methodologies. This would not actually improve the confidence of any audience member, as the AI would still have the same flaws as the methodology AI, due to being created by the same team.

Furthermore, the AI heavily favours the methodology of Cueball's AI, and may be biased. It shows a normal distribution, with a singular outlier to the far right with an arrow above. It can be inferred this data-point represents the AI's methodology. It is a significant outlier, and as such it is probably not an accurate representation of Cueball's AI. Alternatively, this could be taken as AI 'nepotism', where Cueball's methodology AI is more likely to select AI-based approaches over others.

The title text is likely a continuation of Cueball's dialogue, saying that when the classifying AI was shown good research methodology descriptions, the AI identified weird spacing and diacritics as the indicators of a good methodology. Cueball then used his AI to figure out where to put these into his own methodology description to improve his research report. Adding weird symbols into a text doesn't improve the quality of the text {{Citation needed}} and hence Cueball may be doing something very similar to p-hacking, where data is manipulated to decrease the p-number, which represents the likelihood the data is a fluke. P-hacking is mentioned in [[882: Significant]]

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

:[Cueball stands in front of a projection on a screen and points with a stick to a histogram with a bell curve to the left and one bar to the far right marked with an arrow]
:Cueball: Despite our great research results, some have questioned our AI-based methodology.
:Cueball: But we trained a classifier on a collection of good and bad methodology sections, and it says ours is fine.

{{comic discussion}}
[[Category:Artificial Intelligence]]
[[Category:Comics featuring Cueball]]