explain xkcd - User contributions [en]

3137: Cursed Number

2025-09-04T14:48:58Z

163.116.145.92: /* Explanation */

{{comic
| number = 3137
| date = September 3, 2025
| title = Cursed Number
| image = cursed_number_2x.png
| imagesize = 388x449px
| noexpand = true
| titletext = Another group of mathematicians is working to put an upper bound on the number, although everyone keeps begging them to stop.
}}

==Explanation==
{{incomplete|This page was created in a CURSED YEAR. Don't remove this notice too soon.}}
In the universe of this comic there exists some number that, through unknown means, is extremely harmful to the human mind to read it - an {{w|information hazard}}. Dangerous pieces of writing like this are a fairly common trope in speculative fiction, such as the {{w|Necronomicon}} in the {{w|Cthulhu Mythos}}, [https://scp-wiki.wikidot.com/scp-033 cognitohazards] in the {{w|SCP Foundation}}, and {{w|Monty Python}}'s {{w|The Funniest Joke in the World|Funniest Joke in the World}}. It is also very similar to the concept of an {{w|illegal number}}.

Naturally, the mathematicians of this world are doing their best, in the interest of public safety, to keep this number away from as many human eyeballs as possible. Through some process they have figured out the number is at least 22 digits long. Numbers this large (greater than a 1022, or 10 sextillion) are extremely unlikely to be found in the day-to-day lives of non-mathematicians (and almost all mathematicians); even if a person spent their entire lives looking at random strings of 22 digit numbers flashing by every millisecond, for a 100 year lifetime, they would still only have about 3 in a (short) trillion chance of seeing the number. Because of the low risk, public officials have deemed it safe for people to go about their daily lives reading numbers again.

In the title text another group of mathematicians are trying to narrow down the number's identity even further. The more attributes of the cursed number the mathematicians identify, the easier it is for someone with morbid curiosity or someone researching more attributes of the number to discover the number themselves and get their mind damaged. This includes the researchers themselves, as they are now willingly going above the lower safe limit, increasing their chances of encountering it accidentally. Furthermore, the cursed number may appear as part of another number; for example, 223 appears as part of 2237. Worse, if the number could be determined in some controllable way that didn't necessarily expose its discoverers, it might be used as a weapon. This echoes concerns about knowledge gained from research on nuclear forces having been used to create atomic weapons. This was also how the Funniest Joke in the World was used in Monty Python.

==Transcript==
:[A large screen with one equation in the middle is shown to the left of three people. The left part of the equation shows a black bar with a skull in the middle:]
: 💀 > 2.6 x 1021

:[Cueball is standing to the right of the screen and further right is Blondie. Blondie is standing behind a lectern with a label in front. Hairbun stands further and holds a paper up in front of her using both hands. The paper shows illegible text surrounding what is visibly the same equation as appears on the screen, with a skull, but not the black bar. None of the text can be read and the skull can only be made out as such, knowing what it is from the screen.]
:Lectern: Math Dept

:[Caption below the comic:]
:Good news: Mathematicians have put a new lower bound on the '''Cursed Number that destroys the minds of all who perceive it'''!
:It's at least 22 digits, which means it's unlikely to be seen by any human no matter how many random numbers they look at.
:They say it's once again safe to view large random numbers without eye protection.

{{comic discussion}}<noinclude>

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Blondie]]
[[Category:Comics featuring Hairbun]]
[[Category:Math]]
[[Category:Comics with cursed items]]

Talk:3135: Sea Level

2025-09-02T17:00:48Z

163.116.145.92:

Holy crud empty page! F1RST P0ST! [[User:RadiantRainwing|RadiantRainwing]] ([[User talk:RadiantRainwing|talk]]) 01:38, 30 August 2025 (UTC)
:2038: Last of the original Star Wars cast dies. —megan [[user talk:megan|talk]] [[special:contribs/megan|contribs]] 02:18, 30 August 2025 (UTC)
::What? If you're trying to get back at me because I was being useless and just "first posting", it's a reference to [[269: TCMP]], and I also, by the way, wrote the whole first paragraph of this explanation. [[User:RadiantRainwing|RadiantRainwing]] ([[User talk:RadiantRainwing|talk]]) 02:50, 30 August 2025 (UTC)
:::Alright, sorry, just realized what you did is a reference to [[493: Actuarial]]. Sorry about that! [[User:RadiantRainwing|RadiantRainwing]] ([[User talk:RadiantRainwing|talk]]) 02:53, 30 August 2025 (UTC)
::::I guess you're one of today's lucky [[Ten Thousand]]...
::::Wait, no, not everyone has read comic 493 by the time they're adults. I'm too lazy right now to calculate how many people learn about comic 493 each day, so I'll leave it as [[356|an exercise for the reader]]. —megan [[user talk:megan|talk]] [[special:contribs/megan|contribs]] 01:01, 31 August 2025 (UTC)
::::This is where it pays to have read every XKCD comic :P [[User:Logalex8369|Logalex8369]] ([[User talk:Logalex8369|talk]]) 16:45, 1 September 2025 (UTC)

This one is related to the [https://xkcd.com/2809/ Moon] comic. [[User:Pgn674|Pgn674]] ([[User talk:Pgn674|talk]]) 01:39, 30 August 2025 (UTC)
:Clearly. [[User:RadiantRainwing|RadiantRainwing]] ([[User talk:RadiantRainwing|talk]]) 01:49, 30 August 2025 (UTC)

Definitely easy to see, even the references are the same…Randall we trust in you not to copy again…《プロキシ》(XKCD中毒者) 19:07, 1 September 2025 (UTC)

::it's almost a repeat. is he running out of ideas? [[user:lett‪herebedarklight|raeb]] 09:54, 30 August 2025 (UTC)
:::Hope not. [[User:RadiantRainwing|RadiantRainwing]] ([[User talk:RadiantRainwing|talk]]) 16:56, 30 August 2025 (UTC)
:::Why do people talk about running out of ideas? That is something I can't imagine. The world throws ideas and absurdities at you all the time. Running out of time to execute an idea - sure. Seems much more likely to be filtering error (have to check current idea against 3000 previous strips). [[Special:Contributions/107.77.205.64|107.77.205.64]] 19:42, 30 August 2025 (UTC)

Larry Niven had a story about alien-made indestructible spaceship hulls, except the makers didn't account for tidal effects when grazing a star. The test pilot was nearly ripped apart, but figured a way to survive. He sued their butts off against the guarantee. He concluded that their home planet did not have a large moon, a Clue. --[[User:PRR|PRR]] ([[User talk:PRR|talk]]) 02:41, 30 August 2025 (UTC)
: Isn't it frakking ridiculous that the Puppeteers, with all their brains, haven't observed or couldn't deduce the existence of tides? I did like the deduction about their homeworld making them nervous and their legal system of blackmail/extortion, though. --DW [[Special:Contributions/2607:FB90:8FA9:E54A:5856:AACD:B913:6DD8|2607:FB90:8FA9:E54A:5856:AACD:B913:6DD8]] 13:59, 2 September 2025 (UTC)

I think I finally figured out the common thread. All the items here are here because they are elements of Life on Earth. The way the explanation was written kind of buried that important part of the comic.

Overall, if you just look at them as unrelated phenomena, then Lightning seems quite common. Islands made by microskeletons, and life-forms which change their form during development seem like they would be pretty common where there is life. Large tides - thought to be uncommon, but don't have much data, and models are hard. [[Special:Contributions/2600:387:4:803:0:0:0:A0|2600:387:4:803:0:0:0:A0]] 18:04, 30 August 2025 (UTC)

All planets with intelligent life we know have tides. In fact one could argue that tides play an important role in the development in life. Thus any intelligent observe is arguably familiar with tides. Thus the text is wrong in arguing that tides are surprising based on the observation that most known planets likely do not have large tides. --[[Special:Contributions/2A01:599:114:9E35:D827:C56:FF88:1858|2A01:599:114:9E35:D827:C56:FF88:1858]] 19:09, 30 August 2025 (UTC)

:Argument has problems - insufficient sample size, selection bias. Nothing in the comic talked about intelligent life.
:The role of tides in development of life certainly makes sense to add.
:Tides are strange in that they are very complex and hard to explain in detail. Fluid dynamics in a very complex, non-ridgid vessel, involve gravitational forces from multiple bodies. [[Special:Contributions/107.77.205.64|107.77.205.64]] 20:00, 30 August 2025 (UTC)

:: Sample size is definitely a problem. Nothing in the comic talks about tides being strange in a cosmic sense. They are just very weird for one of the two observers from earth. --[[Special:Contributions/195.63.76.62|195.63.76.62]] 20:39, 30 August 2025 (UTC)

:All planets with intelligent life that we know of also have microwave ovens and television cameras and rubber ducks. Perhaps those are also essential for the long-term continued existence of intelligent life? [[User:PotatoGod|PotatoGod]] ([[User talk:PotatoGod|talk]]) 19:09, 31 August 2025 (UTC)

::Well, I can confirm that microwave ovens are essential for the continued existence of this intelligent lifeform. [[Special:Contributions/159.118.184.96|159.118.184.96]] 04:47, 1 September 2025 (UTC)

I'm shocked that Randal didn't include some sort of reference to climate change- and how tides effectively, at least in 2025 and for the foreseeable future, dwarf sea rise due to melting ice. [[User:Seebert|Seebert]] ([[User talk:Seebert|talk]]) 20:18, 30 August 2025 (UTC)
:On a (twice-)daily basis, yes. But that's like saying an unseasonal/hyperseasonal cold snap belies the possibility of global warming. (If that's the point you're trying to make.)
:And I'm not sure if you're saying that Randall "is the sort of person who would go on and on about climate change, but for soe reason he surprisingly didn't do so here" or "he really ought to be mentioning climate change at every opportunity, but he missed the opportunity to convey the concept"..? I'd disagree with ''both'' of those assessments of his (non-)inclusion here, though, and perhaps you're even coming from a completely different third direction that I might or might not understand. But really not the place to discuss it, as he obviously hasn't made that part of the joke/message in this comic. [[Special:Contributions/92.17.62.87|92.17.62.87]] 23:27, 30 August 2025 (UTC)

Lightning should be common throughout the universe, as the ingredients for it (planetary atmospheres containing things like dust that can build up differential static charges through agitation) appear to be. It's still a very weird phenomenon, with many aspects not understood (how does the triboelectric effect work, can breakdown patterns be predicted, wtf is going on with sprites and ball lightning, etc) but it really isn't likely to be rare. --[[Special:Contributions/81.96.108.67|81.96.108.67]] 05:48, 31 August 2025 (UTC)

Ten feet tidal range on a remote island - isn't this too much? I thought it should be less, with stronger tides only in some gulfs where an amplification exists. https://en.wikipedia.org/wiki/Tide figure 15 shows 5 feet tidal range maximum
: In the channel tides can get pretty high and some parts of it would be remote islands by European standards. Also the comic doesn't mention remoteness. --[[Special:Contributions/195.52.138.253|195.52.138.253]] 18:42, 31 August 2025 (UTC)

Significant tides can also bother or surprise people who are used to comparatively smaller tides. I should know, I am one of those people. I live by the Mediterranean Sea and any time I go to the beach on the Ocean, I am worried that I will once again lose my towel to the moving shoreline... [[Special:Contributions/2001:861:51C2:B540:1593:36EE:75F9:1F83|2001:861:51C2:B540:1593:36EE:75F9:1F83]] 18:35, 1 September 2025 (UTC)

^V^ 8th place! Learning English lol…love autocorrect. in South Carolina, tides are HELL on coast《プロキシ》(XKCD中毒者) 19:05, 1 September 2025 (UTC)

Rolled over to tuesday and no new comic?? {{unsigned|SteveTheNoob|23:40, 1 September 2025}}
:It's still (as we write) Monday for Randall, even if it's ''slightly'' after midnight for some of us Rightpondians. And there are have definitely been more extreme 'delays' to the scheduled comics. Take a deep breath, man... If you have to go to sleep and wake up to the comic, then that's what you have to do... [[Special:Contributions/92.17.62.87|92.17.62.87]] 23:48, 1 September 2025 (UTC)
::I thought Randall would just publish using +00 timezone for the love of the game. Oh well, I’ll stay awake until he publishes {{unsigned|SteveTheNoob|00:40, 2 September 2025}}
:::It just varies so much. Sometimes it's "late afternoon 'tommorow'", for any given day, sometimes it has been so early, by ±0 UTC standards, that one wonders if he was effectively staying up to post it 'very late the night before'.
:::When he was on his book tour over this side of the Atlantic, I know at least some of them were 'sensibly' posted at times relative to his being in these time-zones (i.e. 5 or hours ahead of the non-'late' instances, usually.
:::Special comics (huge and/or dynamic ones) seem to be posted any time at all, at least by my possibly faulty combined recollection, which is perhaps due to last-minute tweaks (the lateness of April Fool comics is such that, whilst ''something'' is often posted, if 1/Apr is a M/W/F, it might have been an emergency-filler, or perhaps brought forward from the W/F/M following - and then days, or occasionally even a week or more, later, it happens).
:::It's only really possible, right now, to go into the edit history of various comics and see when they were uploaded by the BOT of the time (or, when BOTs have been temporarily or permanently broken, when a human editor decided it needed doing manually). This introduces some small polling-lag and response time between 'Randall time' and 'wiki time', but if you're eagerly awaiting the comic ''here'', that's probably the end-timing that most interests you.
:::I can't recall any "so late, it was almost Randall's tomorrow" instances, recently, but there was a "so early, it was not too long after his prior midnight". And if Randall ever uses an automated method of posting, I think it's only for exceptional circumstances (not noticably for individual strips, that is - things like the Time comic probably were automated-and-queued, out of planned necessity).
:::And you asked ''before'' 00:00 UTC (I restored the time... and used the Unsigned template as a quickish way to overcome you apparently not using <nowiki>~~~~</nowiki> properly), so even if he were of that habit, you were asking too soon. If he was supposed to be posting at 24:00 UTC, anyway. - Quickly checking, though, and he still hasn't posted as of this moment. But it's still only late evening on Monday, where he is, and has maybe a couple more hours to spare before it becomes notably (and maybe fashionably) late. If you're under UK or one of the EU timezones, that's a long time to wait up. Not sure even ''I'' should be here, right now, though I do have my 'reasons' for it.
:::No, still no change on xkcd.com, just checked before I signed it off. Whether you'll get more or less sleep than myself, I leave up to your circumstances, possibly your other morning commitments. But I'm expecting to see the Monday comic in a few hours, when I check, even though that'll be actually the start of my own Tuesday. [[Special:Contributions/82.132.239.156|82.132.239.156]] 02:00, 2 September 2025 (UTC)
:The new comic is out now, although I don't think explainXKCD has updated yet.[[Special:Contributions/47.150.145.249|47.150.145.249]] 04:46, 2 September 2025 (UTC)

Not sure the premise of this comic is correct. The sun generates tides on Earth of about half the amplitude of the tides generated by the moon, and those vary on close to the same period. Tidal force is proportional to rM/R^3, where r is the radius of the planet experiencing the tide, M is the mass of the body creating the tide, and R is the distance between them. Something like Gliese 581c is 6.8 times the mass of Earth, and assuming comparable density, would have r = 1.9 times the Earth. The star Gliese 581 is 0.3 times the mass of our Sun, and the planet orbits at R = 0.07 that of earth. So we have 1.9 * 0.3 / 0.07^3, a star-induced tidal force on Gliese 581c of more than 1600 times that of the Sun on Earth, and more than 800 times that of the Moon on Earth. So, while large moons near a planet might be uncommon, those aren't the only sources of tides comparable to those on Earth.[[Special:Contributions/163.116.145.92|163.116.145.92]] 17:00, 2 September 2025 (UTC)

Talk:3135: Sea Level

2025-09-02T17:00:24Z

163.116.145.92: