explain xkcd - User contributions [en]

2971: Celestial Event

2024-08-13T07:52:31Z

162.158.129.163:

{{comic
| number = 2971
| date = August 12, 2024
| title = Celestial Event
| image = celestial_event_2x.png
| imagesize = 471x300px
| noexpand = true
| titletext = If we can get a brood of 13-year cicadas going, we might have a chance at making this happen before the oceans evaporate under the expanding sun.
}}

==Explanation==
{{incomplete|Created by a BOT THAT APPEARS EVERY FOUR POINT THREE BILLION YEARS - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic multiplies the fraction of time that selected classes of celestial events occur in the sky over a particular location on the Earth's surface, in this case, Cambridge, Massachusetts, where the cartoonist was living when this comic was published. The resulting product is the expected frequency that all of them would occur at the same time at that location. The value he calculates is once every 4.3 billion years. This is in the same ballpark as the current age of the Earth, about 4.5 billion years.

The calculation itself is not going to be accurate, which is likely part of the joke.
Multiplying probabilities only works for random variables that are entirely independent. If nothing else orbits are (luckily) not random{{cn}}.

Conversion of "days" and "months" to fractional years, required for conservation of units in the equation, is ambiguous as presented due to the leap year phenomenon and the inconsistent number of days in a month. Differing values for these fractional years yield a range of frequency solutions between 4.2 and 4.4 billion years. If the value for days in a year is given as 365.25 (the mean value for all years, ignoring infrequent additional 'leap year' corrections), as in the first term of the equation ((20/365.25)/11), and the mean value for days in two months is given as 60.9 as in the second term ((60.9/365.25)/50), the result is 4.2995 *10^9 years.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
Approximate frequency in my area

active northern lights: 20 days per solar cycle

a naked-eye "Great Comet": 2 months every 50 years

total eclipse: once every 350 years

clear skies: 50% of the time

17-year ciada emergence: 2 months every 17 years

opening bracket

20 days over 11 years multiplied by

2 months over 50 years multiplied by

1 over 350 years multiplied by

one half multiplied by

2 months over 17 years

closing bracket to the power of -1

equals 4.3 billion years
{{comic discussion}}

2684: Road Space Comparison

2022-10-14T08:59:48Z

162.158.129.163:

{{comic
| number = 2684
| date = October 12, 2022
| title = Road Space Comparison
| image = road_space_comparison_2x.png
| imagesize = 740x1157px
| noexpand = true
| titletext = I wonder how hard it would be to ride an electric scooter in a hamster ball.
}}

==Explanation==
{{incomplete|Created by a WALKABLE ELECTRIC HAMPSTER BALL ENJOYER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
The comic is a parody of a common comparison done in arguments for walkable cities - the amount of usable space taken up by cars and car-centric infrastructure that could be eliminated for other useful public amenities. The first of these may be from 1965[https://www.ltmuseum.co.uk/collections/collections-online/posters/item/1983-4-7561].

The first 4 images are common, real-life comparisons involving people walking, people on bicycles, public transport, and cars, which distinctly show how cars take up significantly more space for the same number of people than the other methods of transport. However, from this point the comic becomes more and more absurd in its comparisons.

The 5th one shows 50 people on what may be a tandem bicycle (although seems more likely to actually be a string of {{w|trailer bike}}s, due to person-separation and being clearly non-rigid). This would obviously be impractical in a city due to the tandem's sheer length and would not be able to work with fewer people due to its sheer mass. The [https://www.active.com/articles/bicycle-built-for-52-pedals-into-guinness-book longest compound cycle] holds 52 people, while an actual tandem bicycle exists that has at least [https://www.pinterest.co.uk/pin/346988346267601955/ 35 seats].

The 6th one involves 20 people driving 40 cars, with each person driving 2 cars at a time by straddling them in the middle. Besides being unwieldy and impractical, it would also be extremely dangerous as the cars could go out of control at any time. Perhaps the cars would be a paired mix of left-hand-drive and right-hand-drive models, although with enough push-rods/levers (to also reach the traditional foot controls, and also gear sticks unless ''fully'' automatic) this might not be as important. However, even if the cars were perfectly safe to drive, it would be unsafe to drive them on most roads; roads with only one lane per direction are common, everywhere from city streets to exit ramps, and attempts to drive a pair of cars down such a road side by side are unlikely to end well.

(Of course, worse than any of these petty safety concerns is the fact that each person takes up twice as much road space, making most infrastructure a bit less efficient.)

The 7th one has 30 cars riding on 6 buses by stacking them on top of each other. Assuming the same people-per-car/bus from the earlier examples, this arrangement would have about 345 people riding on the same road! (Unless, of course, the buses are carrying 30 cars ''instead of'' their normal passengers.) In addition, people getting out of the cars when they reach their destination would be a problem for most cars in this arrangement due to them being stacked under other cars or surrounded by them. And as in the previous example, it would be impossible to safely drive anywhere without two clear lanes...and the body count would be considerably higher.

The 8th panel has 50 people in hamster balls. Randall has shown his interest in human sized [[:Category:Hamster Ball|hamster ball]] transportation before, and indeed this would be an enjoyable way to traverse a road, provided no other hamster balls try to drive into you and knock you off the road. The image shows 39 hamster balls, implying that roughly one in four has a passenger; under these constraints, they appear to be slightly more efficient than cars. Another explanation for 39 balls is that there are more hamster balls than are able to be shown on the road diagram.

The 9th panel has 40 tiny cars pulling a big one. Such feats of strengths are a common sight while setting world records, so maybe this is a world record attempt by the cars in question. It is unknown how many people fit in the big car; judging by its size, it likely fits more than a single bus and less than three.

The 10th panel is a 50 person variation on the classic {{w|wolf, goat and cabbage problem}} (which has also been [[2348: Boat Puzzle|referenced before]] by Randall) except this one involves 30 goats, 20 cabbages and 10 wolves trying to cross the now-flooded road with a single boat. It is not known how many people (or cabbages for that matter) the boat fits, but since humans significantly outnumber the goats, cabbages and wolves, it seems like a much simpler problem, though not necessarily without difficulty. It is, however, rather off that there is a conveniently placed dock at the edge of the water, implying that the road gets flooded often enough to warrant a permanent dock to be installed.

The initial bicycles and singular bus are actually (mostly) using the left-hand lane of the three shown, for whatever reason. This would not be unusual on British highways or {{w|Left- and right-hand traffic#Worldwide distribution by country|other countries}} using their system, whether the lanes seen are just one of the directional carriageways of a multi-lane split highway or the centre-lane is a gantry-signed {{w|Reversible lane|'tidal lane'}} of a fully two-way street. Though it is considered bad practice to ride bikes three-abreast and across lanes, and would (intentionally or otherwise) generally annoy motorists. Yet people who have to walk on a road (due to no footway) are advised to walk facing oncoming traffic (the right-hand side, in the same jurisdiction) and not bunched up. It would be interesting to know why Randall, much more familiar with US road conventions, would have offset these various road-users the way he did (rather than hogging the central lane, or across the ''entire'' highway width as he did with the other diagrams in the series).

The title text proposes a problem related to another alternative form of transport — the electric scooter. Randall wonders how well an electric scooter would function when run inside the hamster ball. While this could function like a spherical {{w|monowheel}}, it might also be very dangerous.

==Transcript==
:[Overhead views of ten segments of highway in two rows with a caption above. Each road segment has a caption and a different scenario.]
:Road Space Comparison

:[50 people in the bottom left of the highway, all fitting into a single lane and taking up about a fourth of the length of the road.]
:50 people walking

:[50 bike riders in the bottom left of the highway, extending about halfway up the road and spilling over slightly into the second-to-leftmost lane]
:50 people riding bikes

:[A single bus, fitting into roughly the same space as the 50 people from the first scenario]
:50 people riding a bus

:[33 cars, taking up the entire length of all three lanes]
:50 people in 33 cars

:[One long string of connected bike riders, curving slightly and extending down the entire length of the middle lane]
:50 people on one tandem bicicle

:[40 cars in pairs, each pair with a single person straddling the windows between them. They take up the entire highway segment and each pair extends partway from the outer lanes into the middle]
:20 people driving 40 cars

:[Six buses on the lines between lanes taking up the majority of the highway, 30 cars arranged in stacks across the top]
:30 cars riding on 6 buses

:[39 evenly-spaced hamster balls with a person inside each, taking up the majority of the highway except a space at the top]
:50 people in human-sized hamster balls

:[An oversized car taking up all three lanes at the bottom of the highway, with a pair of ropes and a beam attatched to the front bumper. The beam is attached to 40 miniature cars in front arranged into four lines]
:One giant car pulled by 40 tiny ones

:[The road is bisected by a large river taking up about half of its original area, with a dock and rowboat attatched to the lower shore. 50 people, 30 goats, 20 cabbages, and 10 wolves are in groups on the same side]
:50 people with 30 goats, 20 cabbages, and 10 wolves.

:You Win.

{{comic discussion}}
[[Category:Hamster Ball]]
[[Category:Animals]]
[[Category:Food]]
[[Category:Logic]]

2659: Unreliable Connection

2022-10-09T01:18:44Z

162.158.129.163: Replaced content with "Did you know that 94% of users will leave a website simply because of low-quality design? It takes less than 50 milliseconds to decide if a visitor likes a website so I..."

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Talk:2672: What If? 2 Flowchart

2022-09-15T10:13:56Z

162.158.129.163:

Given: you just bought what if 2 -- why isn't "sit in your room reading 'What if 2' as if you have no obligations in the world" an option on the first what do you do? The answer is even a page number. -{{unsigned ip|108.162.216.227}}
:I think the concept is how to use the book in your everyday life. i.e. Match your real-life quandaries to the book's good advice. [[User:N0lqu|-boB]] ([[User talk:N0lqu|talk]])
::Maybe you just want to read a good book every day? [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 16:05, 13 September 2022 (UTC)

I added a table for the flowchart; does anyone have any better headers for it? {{User:PoolloverNathan/Signature}} 16:50, 13 September 2022 (UTC)

Is any of those order links for What If 2 offering PDF version? -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 20:34, 13 September 2022 (UTC)
:You could buy the Google Play Books version and download as .acsm [https://support.google.com/googleplay/answer/179863 with this]. From that, you could open it with the Adobe Digital Editions app which is... less than ideal to say the least. But from there you will get a DRM protected .epub file. There are ways to remove the DRM, but that's as much as I can say. Long story short, just buy the ebook and don't get in trouble. [[User:TheMegax|TheMegax]] ([[User talk:TheMegax|talk]]) 13:20, 14 September 2022 (UTC)
:Judging by the phrasing of the question I think they were asking about a legal, paid copy but as a pdf- perhaps for convenience or if the books don't ship to a certain country [[User:Char Latte49|Char Latte]] ([[User talk:Char Latte49|talk]]) 04:22, 15 September 2022 (UTC)

I've spotted a small logic bug committed by Randall: What if...the diner is in Rome? [[Special:Contributions/141.101.76.117|141.101.76.117]] 17:48, 14 September 2022 (UTC)
:There aren't any good diners, but there ''are'' plenty of denarii. I think that's what you're being confused with... :-p [[Special:Contributions/172.69.34.84|172.69.34.84]] 20:31, 14 September 2022 (UTC)

zach weinersmith paid tribute: [https://www.smbc-comics.com/comic/interesting-4 on this day] SMBC's comic was two faceless stickmen against a white background (stickmen are drawn rarely in smbc, and normally they have faces) and the votey was "there's a new xkcd book! go buy it!". also the joke was a math joke (referencing the smallest uninteresting number paradox). --[[Special:Contributions/172.69.68.29|172.69.68.29]] 02:50, 15 September 2022 (UTC)
: AWESOME! Perhaps we should host the explainsmbc wiki here until they get their own? [[Special:Contributions/172.71.158.119|172.71.158.119]] 04:28, 15 September 2022 (UTC)

bruh randall out here spoiling what if 2 i can't even[[Special:Contributions/162.158.129.163|162.158.129.163]] 10:13, 15 September 2022 (UTC)

Talk:2669: Things You Should Not Do

2022-09-08T07:36:36Z

162.158.129.163:

Seems like this could become a series. [[Special:Contributions/172.68.210.31|172.68.210.31]] 20:42, 7 September 2022 (UTC)
:Maybe. But I don't think it will be.
:What I was thinking was that there are clearly, on average, around 43  items per 'page', up to this point. This page shows only 19 items (both pre-New and New, or 20 if the "New" line counts as one, don't know if multilines reduce the number of numbered items ler page), so either it's been{{Citation needed}} manually split/new-paged (for changing aesthetics) or else it is highly varying according to the font-height/multiline-wrappings in use beforehand. Or perhaps we should expect around the same number of 'newer New' items to complete this page before the next page number is automatically started to be populated. [[Special:Contributions/172.70.86.8|172.70.86.8]] 20:53, 7 September 2022 (UTC)
#156,819 looks like a reference to the Phineas and Ferb title sequence, and the episode Oil on Candace and probably more relevant here, What If 84. [[Special:Contributions/108.162.210.233|108.162.210.233]] 21:49, 7 September 2022 (UTC)
:It's true that it could be a reference, but I think I recognized most of the topics on the list as being mentioned in some what-if article from the archives--in the case of the "painting" one, https://what-if.xkcd.com/84/. [[User:Dextrous Fred|Dextrous Fred]] ([[User talk:Dextrous Fred|talk]]) 22:13, 7 September 2022 (UTC)
Added a transcript, hopefully it isn't too terrible. (also first explainxkcd edit!) [[User:Merrybot|Merrybot]] ([[User talk:Merrybot|talk]]) 21:52, 7 September 2022 (UTC)

Any indication what the purpose of the misspelling of ''hemorrhagic'' as ''*hemorraghic'' might be? XKCD is usually typo-free, which makes this look deliberate – but why? [[Special:Contributions/172.71.94.3|172.71.94.3]] 00:29, 8 September 2022 (UTC)
: I assume just a typo by Randall Munroe. [[Special:Contributions/172.70.214.79|172.70.214.79]] 02:11, 8 September 2022 (UTC)
: "XKCD is usually typo-free" Oh, they do happen every now and then but usually get corrected eventually by Randall. Nothing too special about this. [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 07:13, 8 September 2022 (UTC)

#156,823 is actually a subplot in the movie "Only Lovers left Alive" by Jim Jarmusch.

2583: Chorded Keyboard

2022-02-19T06:56:38Z

162.158.129.163:

{{comic
| number = 2583
| date = February 18, 2022
| title = Chorded Keyboard
| image = chorded_keyboard.png
| titletext = And even though it all went wrong / I'll stand before the lord of song / with nothing on my tongue but 'I don't understand, I swear I backed up my keyboard config before messing with it'
}}

==Explanation==
{{incomplete|Created by LEONARD COHEN - Someone with proper computer knowledge should probably elaborate on the terms "chorded keyboard" and "keyboard config". Do NOT delete this tag too soon.}}

This strip is a parody of the first verse (and in the title text, the end of the last verse) of Leonard Cohen's "Hallelujah". Cueball has somehow set up his computer so that, upon pressing a certain combination of keys on his keyboard, the system will automatically type out the word "hallelujah" (xkcd's all-caps typesetting makes it unclear how the word is capitalized).

Technically, a {{w|chorded keyboard}} is one in which (nearly) all inputs are made by simultaneous pressing of a given combination of a limited number of keys, such as a literal handful of non-alphabetic keys that the user learns to combine to represent the key-presses of more standard keyboards. The workings of such a keyboard tends to be handled internally, sending to the computer the signal(s) that ''would'' have been sent from its larger cousin.

By inclusion of traditional key descriptions for a 'standard' keyboard (e.g. the 104-key US QWERTY version that Randall is probably most familiar with), the meaning is probably instead that of using a combination of normally single-use keys (the 'H' and a cursor) with others, including modifiers ('shift' and 'control'), i.e. 'chording' ''with'' his keyboard. This seems to go beyond regular use (shift and a character changing the character case, ctrl and a character may give a editing command) or normal combinations (ctrl, alt and the 'e' may result in the 'é', where the keyboard does not otherwise support it) and even goes beyond [[378: Real Programmers|emacs-like serialised metacommands]] which is a software feature. It seems more likely that such a setup is handled within the computer, either defined within the OS or (as is often the case with specialist configurable gaming keyboards) via the driver installed to mediate such esoteric keyboard combinations as the user has predefined for themselves.

Cueball's combination-keypress may in fact be better termed a 'macro', in some contexts. The single event, somehow triggered by this particular simultaneous multi-key input, invokes the injection of a pre-programmed sequence of standard characters into the appropriate text-buffer/-stream in leiu of manual input.

The title text spoofs the last verse of the song, with "Hallelujah" being replaced by Cueball trailing off musing about having apparently lost the backup of his keyboard configuration, implying that he ended up in a position where he would want to restore said backup (for instance, having tampered with it to the point he is no longer capable of operating the keyboard efficiently, if at all).

As added irony, while in the original that verse is hopeful, with the singer being thankful for experiencing joy even from a relationship that ultimately failed, contrarily in the alt text Cueball is apparently expressing regret. Or, if taken literally, it could instead imply that God himself is questioning Cueball about his tampering with software, which could fit with the running gag of [[Cueball Computer Problems|Cueball's (often self-inflicted) computer problems being hyperbolically atrocious]].

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
[Cueball is sitting in an office chair at his desk, hands on his keyboard, looking at his desktop.]
I heard there was a secret chord

That David press and it typed a word

[The camera zoomed in on Cueball, and we see him from the waist up]

But you don't use a chorded keyboard do you

[The third frames are like the first, except Cueball's arms are moved]

It goes like this <control> and <shift>

The other hand hits H and <left>

[The fourth frame is like the first and third, but the arms are moved again]

And All at once it types out
Hallelujah

{{comic discussion}}