explain xkcd - User contributions [en]

1963: Namespace Land Rush

2026-01-17T22:33:21Z

Nosh:

{{comic
| number = 1963
| date = March 5, 2018
| title = Namespace Land Rush
| image = namespace_land_rush.png
| titletext = You can also just mash the keyboard at random, but you might end up with a gibberish name no one can pronounce.
}}

==Explanation==

When a new web service starts, such as a forum, a social media server or an email portal, the people who sign up get to choose their username on the service, which, in most cases, blocks future users from using those usernames. Common names such as "john" are likely to be taken quickly. This is analogous to the way that {{w|Land run|some land}} was distributed to settlers (and/or {{w|Land claim#Mining claim (United States)|prospectors}}), in America, with the first to claim able to speculatively choose the 'best' land.

This comic is a list of usernames [[Randall]] suggests should be used if they are available.

The title text is a self-reference to "xkcd"; the name of the comic is a purposefully unpronounceable phrase created by Randall. The fact that an unpronounceable name is portrayed as a disadvantageous outcome is also humorous because the comic has a section dedicated to unpronounceable usernames.

(Note: for a more serious list of problematic user names to block from a service provider’s point of view, see [https://ldpreload.com/blog/names-to-reserve Hostnames and usernames to reserve] as well as [https://tools.ietf.org/html/rfc2142 RFC 2142].)

==Table==
{| class="wikitable"
!style="width:30%"|Entry
!style="width:70%"|Explanation
|-
!colspan=2|Straightforward (Usernames that a person would use under typical circumstances)
|-
|<Your usual username, if any>
|Most internet users will have settled on some unique handle that they try to use across all platforms. Even if this wasn't a new service, most people would try this first.
|-
|<Your given name>
|More rare is using one's nickname or first name as their username, since the amount of common names will mean many users share a name. Thus, if you can get your given name, you will have a simple username that many others wanted, and without resorting to prefixes or numbers (i.e. Xx_MyName00_xX)
|-
|<Your full name>
|Similar to your given name, but slightly more unique since a last name and/or middle name is added.
|-
|<Initial><Surname>
|A common second choice if a given or full name is already in use. This is generally mandated on business networks for reasons of uniformity and avoidance of unprofessional or obscene usernames, which some social sites may also adopt.
|-
|<Surname>
|Possibly available if your last name is more uncommon; names like "Smith" or "Kim" will probably be taken faster than even given names.
|-
!colspan=2|Recognizable (Usernames that would make it look like the email came from an official source within the organization named)
|-
|Google
|Registering the name "Google" would allow for communicating on the site (or even outside of it) with a name that appears to be an official Google account. For any of the examples in this section, you would select the names for the same reason. This has been done in the past with both [https://twitter.com/BiIIMurray humorous] and [http://www.chicagotribune.com/bluesky/technology/ct-russian-twitter-account-tennessee-gop-20171018-story.html nefarious] results.
|-
|iPhone
|Many services would mark messages sent from an iOS client on iPhone as "sent from iPhone".
This could make people believe that your messages are sent from an iPhone even if you don't own one.
|-
|Facebook
|Similar to Google above.
|-
|Bitcoin
|One could pose as the Bitcoin Core development group by using this handle and/or scam uninformed users interested in cryptocurrencies.
|-
|Obama
|Impersonating the former president, supposedly to send messages as them to make them seem bad (or not).
|-
|Canada
|Impersonating a whole country might get you in trouble.{{Citation needed}}
|-
|NFL
|The American "National Football League".
|-
|Garfield
|
|-
|<Your city>
|Impersonating the official account for your place of residence.
|-
|NASA
|The American "National Aeronautics and Space Administration". Randall worked there as a contract programmer and roboticist.
|-
|<Name of person who runs the service>
|Impersonating the site owner can allow you to gain the trust of users.
|-
!colspan=3|Causing Trouble (Usernames that might cause errors when mixed with the service's back-end code)
|-
|User
|This is usually the default username for a non-administrative account. This may trick a user that this is owned by the operator of the service.
|-
|Username
|See above.
|-
|Name
|See above.
|-
|You
|Services often list parts of a 'conversation' with the registered username of the contributor, but may label your own contributions with "You" for easier reading. Anyone naming themself "You" could cause some confusion, with the "You" comments being (at least briefly) read by other users as being comments that ''they'' made.
|-
|Guest
|Attempts to fool users into thinking that they have a guest account.
|-
|Account
|The opposite of "Guest" (someone without an account). However, for someone with an account, their username will usually be displayed. There is an active user named [[user:Account|"Account"]] on Explain XKCD.
|-
!colspan=2|Causing More Trouble
|-
|Admin
|Impersonating to be a system administrator will let someone fool people and cause a lot of trouble. In particular, it could be used to obtain SSL certificates by demonstrating ownership of a supposedly internal address.
|-
|Administrator
|See above.
|-
|System
|Pretending to be a system-controlled account - might give permissions if the server checks by name.
|-
|<Name of service>
|Pretending to be the official account of the service. There are a lot of spammers who did this on Explain XKCD.
|-
|Help
|Pretending to be the help account. This could lead to many questions from new users.
|-
|Error
|This may trick users to do what the user says as they could claim that it was a legitimate error.
|-
!colspan=2|Impossible to Say
|-
|Hyphen-Emdash
|Could be read "Hyphen hyphen Em dash" or "Hyphen dash em dash". In addition, in many markup languages (such as the one used by this very wiki) one can create a larger hyphen with some variation of an "&mdash" command, which could theoretically be pronounced "emdash."
|-
|Dash-8hyphen-8
|Could be read "Dash dash eight hyphen dash eight" or "Dash hyphen eight hyphen hyphen eight". "Hyphen eight" sounds like "hyphenate".
|-
|Zero0ne2numeral2
|Mixing names and numerals makes this confusing. Could be read "Zero zero one two numeral two" or "Zero zero ne two numeral two" or "Zero oh ne two numeral two" or "Zero numeral zero ne numeral 2 numeral numeral 2".
|-
|KrisasinHemsworth
|This would be confusing to say out loud, as it would sound like the user was saying that their username was "Chris," spelled the same way that famous actor {{w|Chris Hemsworth}} spells his name. However, the actual username uses the name "Kris," spelled a completely different way than Chris Hemsworth's name, and the phrase "as in Hemsworth" being also part of the username, rather than a clarification of the spelling of "Kris" as would be assumed.
|-
|TheWord&Ampersand
|This would also be confusing and difficult to communicate, as anyone trying to read the username to someone else would say "The word ampersand ampersand" which could be interpreted as "ampersand&" or "ampersand ampersand". Having the phrase "the word" in front of a symbol makes it quite difficult to communicate which variation of ampersand (word or symbol) is actually being referred to.
|-
|ZettaWith3Teees 
|Read aloud, this would lead the listener to expect a username of 'Zettta'. Clarifying that "with three tees" is text and not description would in turn make it difficult to explain the spelling of 'Zetta' with two 't's, and 'Teees' with three 'e's.
|-
!colspan=2|Misc
|-
|<Single Letters> and <Single Numbers>
|These are highly valuable. The Twitter handle "@n" for example is constantly bombarded with offers and hacking attempts.
|-
|<Common Words>
|Also highly valuable; overlaps with "Recognizable" and "Causing (more) Trouble".
|-
|<SQL/JS Injection>
|Codes such as "Drop Table" intended to cause errors or even damage the service's back-end code. (See [[327|Comic 327]])
|-
|ASDF and QWERTY
|Since those keys are right next to each other (on English language layouts), they are often typed as placeholders.
|-
|Yes
|This might be a [[Beret Guy]]-esque misunderstanding when filling out the sign up form. When encountering the form field "Username:" someone may type "Yes" (as in "yes, I want a username") instead of specifying it.
|-
|Bot and Computer
|Pretending to be a bot.
|-
|Blocked
|When users get banned or blocked, their name is often replaced by a string like this.
|-
|Deleted
|Some services like Reddit keep up user posts and data after account deletion, marking the content as submitted by the user "[Deleted]" or "Deleted".
|-
|Jeeves
|Might refer to {{w|Ask Jeeves}} (now Ask.com), a Internet Search Engine.
|-
|Narrator
|In books, radio plays and movies it is quite common to have a narrator explain parts of the story. In an online forum however, it is not.{{Citation needed}}
|-
|Internet
|"The Internet" sometimes refers to a large group of users, the collective hive-mind if you will. However, there cannot be a single user account speaking on behalf of them, as they aren't a single entity.
|-
|NPC
|Stands for Non-player character.
|-
|Password
|If the user accidentally typed their password into the username field, this would be the result.
|-
!colspan=2|Permissive Character Sets
|-
|<Space>
|Usernames containing only whitespace can not only be confusing for other people, but often systems 'trim' (remove whitespace at the beginning and end) user input. If the username was only made of spaces, after trimming it would be completely empty, which can cause a whole slew of other problems.
|-
|<nowiki>@ é |</nowiki>
|The @ separates the local part from the domain part of email addresses. If a service decides to create email addresses for their users, they will have a hard time if they allowed the "at" character as part of a username.
é is encoded in many character sets, like Latin-1 and Unicode. In Unicode, it can even be described either "U+00E9 LATIN SMALL LETTER E WITH ACUTE" or as the sequence "U+0065 LATIN SMALL LETTER E" and "U+0301 COMBINING ACUTE ACCENT". If a system uses {{w|Unicode normalization}} after the check if the username is available, this might allow someone to take over someone else's account.
|-
|<nowiki>“ ” " ‘ ’ ' `</nowiki>
|Various quotation marks.
“, ”,‘ and ’ (Unicode quotes): can expose a system's inability to handle multi-byte-encodings. If they are converted to their ASCII counterparts, they might cause code injections.
' and " (ASCII single and double quotes): often used as string delimeter (causing the rest of the name to be interpreted as HTML, or worse, code.
` (ASCII grave / backtick): Sometimes used as string delimeter; Perl (which some websites are still programmed in) executes commands ("shell code") when between backticks.
|-
|<NBSP>
|Unicode character "U+00A0 NO-BREAK SPACE". Similar attack vector as <Space>, but some programming languages will not strip non-ASCII whitespace (therefore the validation will pass).
|-
|<nowiki>\ . #</nowiki>
|The backslash is very often used for "escape sequences", that get expanded to other characters. (\n -> newline, \t -> tab character, \b -> backspace character (deletes the character to its left), etc.)
The period can be problematic in emails. RFC 2822 forbids periods at the beginning or end of the local part or more than one period in a row.
In URLs, the Octothorpe (#) is used as the 'anchor'. Anything following a # will not be transmitted to the server. If a user is named 'logout#blahblah' (which might be a valid username) and the user profile is located at http://example.com/<the_username>, the server might generate the URL http://example.com/logout#blahblah. Since the URL will be truncated at the '#', any user attempting to view this profile will be logged out of the service.
|-
|<RTL override>
|The right to left override is an Unicode character which forces text after it to be laid out right to left. Thus, in left-to-right locales, it flips everything after it. This can be rather amusing if permitted. (See [[1137|Comic 1137]])
|-
|<nowiki>– - _ /</nowiki>
|Includes both the em-dash and the hyphen, which are easily confused and are highly unusual for user names. The forward slash is also the path delimeter for URLs; if user profiles are located at e.g. <nowiki>http://example.com/user/the_username</nowiki>, this can cause obvious issues. Explain XKCD does not allow <code>/</code> in usernames.
|-
|<Any emoji>
|Current databases are not set up to store emojis as characters. Explain XKCD does allow emoji in usernames.
|-
|","
|In CSV files this separates one column or data item from another. This could cause bugs if the usernames are used as part of a CSV file since the next column on the row could be left blank filled with other data.
|-
|<nowiki>&NBSP</nowiki>;
|The special entity in HTML (web page language) for a non-breaking space, or a space that prevents an automatic line-break at its position. When rendered as part of an HTML page without sanitization, this would only display a space. However, if the username in question is really long, this would increase the page's width (details needed).
|-
|<nowiki></HTML></nowiki>
|This is trying to inject code for the web page using the user name. If the user name is not sanitized and does not have special characters encoded, this HTML end tag could end the HTML document, leading to page errors.
|-
|&LT;/HTML&GT;
|&lt; and &gt; are special character entities in HTML that represent < and >, repectively. So all together, when rendered as part of an HTML document, this would print "<nowiki></HTML></nowiki>" Although this would look similar to the previous <nowiki></HTML></nowiki> entry, it would be unlikely to cause problems as the symbols are not interpreted if encoded as special entities.
|-
|OkThisIsKindOfConfusingButIt's <LessThan\ForwardSlashHTML GreaterThanActualGreaterThan Symbol>Yes,ThatWasAllPartOfThe Name,ButSoIs...Ok,LetMeStartOver”
|The abundance of symbols and symbol related worlds and phrases such as ActualGreaterThanSymbol would make this extremely difficult to vocally communicate to another person. This difficulty is further compounded by the parts at the beginning and end, which sound like they are part of the explanation despite being part of the name itself.
|-
|}

==Transcript==
'''Namespace Land Rush Cheat Sheet'''
(Note: if an item is "quoted", it is meant literally, otherwise the reader is supposed to substitute their own information for words in <angle brackets>)

When a new service appears that lets you register a name, here are some you may want to try and get first:

* Straightforward
** <Your usual username, if any>
** <Your given name>
** <Your full name>
** <Initial><Surname>
** <Surname> (Bold & Slightly Unconventional)

* Recognizable
** "Google"
** "iPhone"
** "Facebook"
** "BitCoin"
** "Obama"
** "Canada"
** "NFL"
** "Garfield"
** <Your city>
** "NASA"
** <Name of person who runs the service>

* Causing Trouble
** "User"
** "Username"
** "Name"
** "You"
** "Guest"
** "Account"

* Causing More Trouble
** "Admin"
** "Administrator"
** "System"
** <Name of service>
** "Help"
** "Error"

* Impossible to Say
** "Hyphen-Emdash"
** "Dash-8hyphen-8"
** "Zero0ne2numeral2"
** "KrisasinHemsworth"
** "TheWord&Ampersand"
** "ZettaWith3Teees" 

* Misc
** <Single Letters>
** <Single Numbers>
** <Common Words>
** <SQL/JS Injection>
** "ASDF"
** "QWERTY"
** "Yes"
** "Bot"
** "Computer"
** "Blocked"
** "Deleted"
** "Jeeves"
** "Narrator"
** "Internet"
** "NPC"
** "Password"

* Permissive Character Sets
** <Space>
** <NBSP>
** <RTL override>
** <Any emoji>
** "<nowiki>&NBSP</nowiki>;"
** "<nowiki></HTML></nowiki>"
** "&LT;/HTML&GT;"
** one or more of the following symbols: <nowiki>@ é | “ ” \ . # " ‘ – - _ / ’ ' `</nowiki>
** "," (including quote marks)
** "OkThisIsKindOfConfusingButIt's<LessThan\ForwardSlashHTMLGreaterThanActualGreaterThanSymbol>Yes,ThatWasAllPartOfTheName,ButSoIs...Ok,LetMeStartOver”"

{{comic discussion}}
[[Category:Comics_with_lowercase_text]] 
[[Category:iOS]]
[[Category:Internet]]
[[Category:Emoji]]

3150: Ping

2025-10-04T06:26:36Z

Nosh:

{{comic
| number = 3150
| date = October 3, 2025
| title = Ping
| image = ping_2x.png
| imagesize = 603x208px
| noexpand = true
| titletext = Progress on getting shipwrecked sailors to adopt ICMPv6 has been slow.
}}

==Explanation==
{{incomplete|This page was FOUND ON A MESSAGE IN A BOTTLE. Don't remove this notice too soon.}}
This comic shows a message in a bottle on the beach, much like [[1675: Message in a Bottle]].

The {{w|Internet Control Message Protocol}} (ICMP) is a network communication protocol that's used among other things for "pings" that are used to see if one machine can successfully communicate with another machine. When you send a ping, your computer sends an "echo request" packet; the receiver sends an "echo response" message back to the sender (the term "echo" refers to the fact that the data in the request is copied to the response). Someone over the sea has initiated this process with a message in a bottle, and [[Cueball]] receives the echo request and responds. However, one difference from ICMP is that bottles cast into the sea don't have a fixed destination, so there's no assurance (or even expectation) that the response will reach the original sender, nor even that the request had even found the originally intended destination. In addition, ping response times are typically measured in milliseconds or at most a few seconds, but here, even in the highly unlikely event that the sea does bring the bottle back to the original sender, this round-trip transmission has an ''extremely'' long ping response time.

Pinging another network node is something typically done when initiating extensive communication with it, or when testing whether network communication is working. The humor here is that a shipwrecked sailor trying to get rescued by casting messages in a bottle wouldn't want to do this: the chance that one message-containing bottle gets found and acted on are slim, and the chance of succeeding with multiple back-and-forth messages is exceedingly low. Instead a stranded sailor would just say they're in need of rescue and describe how best to find them.

ICMP is a supporting protocol of the {{w|Internet Protocol version 4}} (IPv4). The newer {{w|Internet Protocol version 6}} (IPv6) uses {{w|ICMPv6}} instead, which the title text references. There is no (technically correct) name to describe both ICMP and ICMPv6, so the comic could not be generic and had to choose one of them. Many people are quite upset that switch from IPv4 to IPv6 has not happened despite the decades it has been available. Those might complain that Randall uses the legacy protocol here. The title text makes a joke out of that possible complaint by pointing out how absurd it would be to expect an higher adoption of IPv6 by shipwrecked sailors compared to the general population.

==Transcript==
{{incomplete transcript|Don't remove this notice too soon.}}
:[Cueball is walking on a sandy beach near the shore. A bottle with a paper inside is stuck in the sand, presumably from being washed up by the tide.]

:[Cueball has picked up the bottle and is reading the message inside, with all text illegible. The messages contents are displayed on the top portion of the panel. There is illegible text written beneath the title of the message.]
:Title Message: ICMP Echo Request

:[Cueball has set the bottle down below him and is now scribbling out a new message, with all text illegible. Once again, there is illegible text written beneath the title of the message, with the contents on the top portion of the panel.]
:Title Message: ICMP Echo Reply

:[Cueball is walking away from the shore now, having set the bottle back into the sea.]

{{comic discussion}}<noinclude>

[[Category:Computers]]
[[Category:Comics featuring Cueball]]

3150: Ping

2025-10-04T06:02:22Z

Nosh:

{{comic
| number = 3150
| date = October 3, 2025
| title = Ping
| image = ping_2x.png
| imagesize = 603x208px
| noexpand = true
| titletext = Progress on getting shipwrecked sailors to adopt ICMPv6 has been slow.
}}

==Explanation==
{{incomplete|This page was FOUND ON A MESSAGE IN A BOTTLE. Don't remove this notice too soon.}}
This comic shows a message in a bottle on the beach, much like [[1675: Message in a Bottle]].

The {{w|Internet Control Message Protocol}} (ICMP) is a network communication protocol that's used among other things for "pings" that are used to see if one machine can successfully communicate with another machine. When you send a ping, your computer sends an "echo request" packet; the receiver sends an "echo response" message back to the sender (the term "echo" refers to the fact that the data in the request is copied to the response). Someone over the sea has initiated this process with a message in a bottle, and [[Cueball]] receives the echo request and responds. However, one difference from ICMP is that bottles cast into the sea don't have a fixed destination, so there's no assurance (or even expectation) that the response will reach the original sender, nor even that the request had even found the originally intended destination. In addition, ping response times are typically measured in milliseconds or at most a few seconds, but here, even in the highly unlikely event that the sea does bring the bottle back to the original sender, this round-trip transmission has an ''extremely'' long ping response time.

Pinging another network node is something typically done when initiating extensive communication with it, or when testing whether network communication is working. The humor here is that a shipwrecked sailor trying to get rescued by casting messages in a bottle wouldn't want to do this: the chance that one message-containing bottle gets found and acted on are slim, and the chance of succeeding with multiple back-and-forth messages is exceedingly low. Instead a stranded sailor would just say they're in need of rescue and describe how best to find them.

ICMP is a supporting protocol of the {{w|Internet Protocol version 4}} (IPv4). The newer {{w|Internet Protocol version 6}} (IPv6) uses {{w|ICMPv6}} instead, which the title text references. There is no name to describe both ICMP and ICMPv6, so the comic could not be generic and had to choose one of them. Many people are quite upset that switch from IPv4 to IPv6 has not happened despite the decades it has been available. Those might complain that Randall uses the "out-dated" protocol here. The title text makes a joke out of that possible complaint by pointing out how absurd it would be to expect an higher adoption of IPv6 by shipwrecked sailors compared to the general population.

==Transcript==
{{incomplete transcript|Don't remove this notice too soon.}}
:[Cueball is walking on a sandy beach near the shore. A bottle with a paper inside is stuck in the sand, presumably from being washed up by the tide.]

:[Cueball has picked up the bottle and is reading the message inside, with all text illegible. The messages contents are displayed on the top portion of the panel. There is illegible text written beneath the title of the message.]
:Title Message: ICMP Echo Request

:[Cueball has set the bottle down below him and is now scribbling out a new message, with all text illegible. Once again, there is illegible text written beneath the title of the message, with the contents on the top portion of the panel.]
:Title Message: ICMP Echo Reply

:[Cueball is walking away from the shore now, having set the bottle back into the sea.]

{{comic discussion}}<noinclude>

[[Category:Computers]]
[[Category:Comics featuring Cueball]]

Talk:3086: Globe Safety

2025-05-08T19:16:27Z

Nosh:

Hello! First time i got to a comic first --[[Special:Contributions/172.69.176.76|172.69.176.76]] 06:17, 8 May 2025 (UTC){{unsigned ip|104.23.175.202}}
:Well [[269: TCM|first of all]] remember to sign your comments :-). But congratz... --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 05:42, 8 May 2025 (UTC)
::Sorry. I now realize that that was an extremely trollish thing to do. --[[Special:Contributions/172.70.92.140|172.70.92.140]] 07:09, 8 May 2025 (UTC) ٠ـ٠
:: Also i MAY OR MAY NOT have permanently altered the editing process of this talk by including arabic numbers in an emoticon.{{unsigned ip|172.70.92.140|07:09, 8 May 2025 (UTC)}}

I believe he indicates that a globe is made by making a copy of the Earth, and then compressing it until it fits on a desktop. Hence having the same mass and thus the same Schwarzschild radius as Earth. I have changed the explanation a bit because of this observation.--[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 05:42, 8 May 2025 (UTC)

Gotta wonder what kind of a desk could support a desktop globe that weighs as much as the Earth --[[User:StumbleRunner|StumbleRunner]]
:[...] desk? Convince me that such a globe wouldn't plunge straight through the Earth's crust and into the mantle. I sense a marketing problem. [[Special:Contributions/172.71.147.69|172.71.147.69]] 07:07, 8 May 2025 (UTC)

Radius. <s>Is there a typo in the comic where 7/10" should be 7/20", i.e., 0.35" as later written? Or would a 7/10" Earth collapse into a black hole nonetheless?</s>[[Special:Contributions/172.71.154.129|172.71.154.129]] 06:40, 8 May 2025 (UTC)
:Nope… the Schwarzchild radius is 0.35", which is indeed 7/20", but the measurement shown on the globe is the diameter, not the radius, so 7/10" is correct. [[Special:Contributions/172.71.178.143|172.71.178.143]] 06:49, 8 May 2025 (UTC)

Isn't there also a jab at the weird way USsians use power-of-two fractions for inch measurements? I've never seen something like 7/10" before, it would be approximated as 11/16".[[Special:Contributions/172.71.95.69|172.71.95.69]] 09:18, 8 May 2025 (UTC)
: It isn't a weird USian thing - it's just the historical way that inches (being a non-metric unit) were divided. The same way that an inch is a 1/12 division of a foot, which is a 1/3 division of a yard, etc. [[Special:Contributions/141.101.98.83|141.101.98.83]] 10:23, 8 May 2025 (UTC)

I think we have a bigger problem: there are millions of globes on Earth! I haven't done the calculations, but that might be enough to turn Earth into a black hole already; if not, I expect at least it would turn it into a star. --[[Special:Contributions/104.23.190.34|104.23.190.34]] 11:44, 8 May 2025 (UTC)

BTW. what would be a 12-inch object with a mass of Earth? Neutron star? Neutron planet? Neutron meteoroid? -- 12:46, 8 May 2025 (UTC)
: Crunching the numbers (thanks to Copilot.microsoft.com):
:* A sphere with a 30 cm radius has a volume of about 1.13×10<sup>-2</sup> m³.
:* Compressing Earth's mass into that volume gives a density of roughly 5.3×10<sup>28</sup> g/cm³.
: That is way way denser than a neutron star. It's doubtful that such a sphere would remain at that density; it would likely explode immediately, or if prevented from doing so, continue to shrink down past 9mm and become a black hole. {{unsigned ip|172.70.110.59|13:26, 8 May 2025 (UTC)}}

'''False precision: .889 cm?''' Could someone please check "0.35 inches (0.889 cm)"? I'm concerned that this is a matter of {{w|false precision}}, with two significant digits for the customary / imperial system precisely converting to three significant digits in SI (similar to the way people obsess over 98'''.6'''F, which is a precise conversion of the estimate of 37C.). Also, I'd suggest that millimeters are preferable to centimeters. [[Special:Contributions/104.23.170.118|104.23.170.118]] 14:11, 8 May 2025 (UTC)

2 × 6.6738×10^−11 m^3⋅kg^−1⋅s^−2 × 5.972168×10^24 kg / (299792458 m⋅s^−1)2 = 0.00887 m , so the current 8.9mm looks good. [[User:Nosh|Nosh]] ([[User talk:Nosh|talk]]) 19:16, 8 May 2025 (UTC)

3086: Globe Safety

2025-05-08T18:59:25Z

Nosh: Every mass below its Schwartzschild radius is already a block hole. It might not have collapsed into a singularity yet (if there are singularities), but that makes no difference outside.

{{comic
| number = 3086
| date = May 7, 2025
| title = Globe Safety
| image = globe_safety_2x.png
| imagesize = 255x448px
| noexpand = true
| titletext = Frankly, given their extreme gravitational fields and general instability, even 12-inch globes should probably be banned.
}}

==Explanation==
{{incomplete|This page was created by an EARTH MASS BOT THE SIZE OF A REGULAR BOT. Don't remove this notice too soon.}}
The {{w|Schwarzschild radius}} of a given object is the radius of the {{w|event horizon}} of a {{w|black hole}} with the mass of that object. The Schwarzschild radius of the Earth is about 0.35 inches (roughly 8.9 mm), meaning if you could hypothetically compress the Earth into a ball that small it would be a black hole (among other effects). The object at bottom right in the comic that looks like a black spot under a sombrero, with a triangular warning sign next to it, is a {{w|Black_hole#Observation|depiction of a black hole}}.

{{w|Globes}}, in this context, are miniature recreations of planet Earth, used to show its features without any of the [[977: Map Projections|typical problems of a flat map]]. [[Randall]] claims that safety standards are in place to ensure that globes are not manufactured at below, or close to, the Schwarzschild radius of the Earth. The suggestion is that any globe of the Earth shares the same mass as the Earth and hence the same Schwarzschild radius. This would indicate that globes are made by creating a literal 1:1 replica of Earth and then compressing it until it has the required size. This would, of course, give the most perfect maps; however, for each globe like this put on Earth, the Earth's mass would increase by its original amount.

The title text suggests that globes up to 12 inches (30.5 cm) should be banned, due to their extreme density and gravitational field. Since they would have the same mass as the Earth, they would exert massive, catastrophic gravitational forces - for a 12-inch globe, 1.75 quadrillion times normal Earth gravity - as well as on its satellites, other planets, etc. However, this would be true for Earth-mass globes of any size, so the 12-inch cut-off would be no less arbitrary than the 4-inch one.

==Transcript==
:[A standard globe of the Earth is shown. It stands on a typical stand which holds it by two arms at the poles, so it can turn around like the Earth does. The Earth is turned so it shows Australia at the bottom and most of Asia, including the entire India to the left. Only the very tip of Alaska can be seen of the Americas. Above the globe there is a double ended arrow that goes to two small lines that align with the edges of the globe (indicating the diameter). The arrow has been split in the middle and two lines of text are written in the gap. Above this text there is another line of text.]
:Remember:
:4 inches minimum

:[Beneath the globe there are two small drawings. The left shows the Earth and to the left of the Earth there is a double ended arrow ending at two lines that indicated the diameter of the Earth going from top to bottom. The distance of this is written in inches to the left. From the Earth an arrow points to another drawing, this time the typical depiction of a black hole, with a "hat" like shape. A triangular warning sign is shown a the top right of the black hole with an exclamation mark inside.]
:7/10"

:[Caption below the panel:]
:The Earth's Schwarzschild radius is about 0.35 inches, which is why safety regulations require desktop globes to be at least 4 inches in diameter.

{{comic discussion}}<noinclude>

[[Category:Astronomy]]
[[Category:Maps]]

3085: About 20 Pounds

2025-05-06T19:29:38Z

Nosh:

{{comic
| number = 3085
| date = May 5, 2025
| title = About 20 Pounds
| image = about_20_pounds_2x.png
| imagesize = 666x278px
| noexpand = true
| titletext = In addition to gravity, burritos interact through the strong, weak, and electromagnetic forces, which is believed to be a major contributor to their popularity.
}}

==Explanation==
{{incomplete|Created by a £20 20-LB PARTICLE. Are any categories missing? Don't remove this notice too soon.}}

The nature of {{w|dark matter}} is a significant unsolved problem in physics. In an effort to solve the problem, [[Cueball]] and [[Ponytail]] appear to have used occult methods to conjure a supernatural {{w|oracle}} (something which would present its own challenges to our understanding of the physical world) in order to demand an answer from it. There may be a pun here, in that they are using 'dark magic' to communicate with something from the 'dark realm' on the assumption that it will know about dark matter. However, the word 'dark' in this context simply means that we do not know how to observe it; dark matter is not evil or satanic{{cn}} (though [[Randall]] may consider it [[:Category:Comics with cursed items|cursed]]).

In general, not all forces interact with all particles; indeed, {{w|gravity}} is the only force that is (believed to) interact with everything. If a force doesn't interact with a particle, then its existence cannot be observed via disturbances in that force. In particular, something that doesn't interact with electromagnetism cannot be 'seen', as photons will pass through it completely unaffected.

Even {{w|neutrino}}s -- famous for interacting with ''almost'' nothing -- still in fact interact via the {{w|weak force}}, allowing them to be detected with sufficiently large tanks of dense material (as most atoms do in fact interact with the weak force, however weakly). A particle that interacts with ''nothing'' except gravity, could only be detected by a gravitational telescope.

However, even if a particle does interact via a given force, an interaction is only possible if energy is conserved. If dark matter is entirely due to a single kind of particle, and the fundamental mass of that particle is ''twenty pounds'' (approximately 9kg) -- an absolutely ludicrous amount of energy for particle physics -- then any interaction would (roughly speaking) have to involve an equally ludicrous amount of other particles being in exactly the right place and time, a coincidence that could easily reach "never in the history of the universe" levels. (By comparison, the {{w|top quark}}, otherwise the heaviest single particle with a mass over a hundred times that of the proton, is still nevertheless around a tenth of a trillionth of a trillionth of a pound.)

Under more normal circumstances, we might still hope to observe the properties of the particle via creating it ourselves under controlled laboratory conditions. But again, there is no reasonable way to focus the energy required into a single particle interaction -- the LHC, for example, peaks at about ten thousand times the mass of the proton, a solid billion times less energy than required -- so that's out too.

Finally, despite all this, twenty pounds is also much too ''small'' to be detectable via gravitational interaction -- its {{w|Perturbation_(astronomy)|influence on the orbits of planets}}, say, or the strength of its {{w|gravitational lensing}} effect, will be entirely negligible. Thus, in the scenario posed by the comic, there is essentially no plausible way to observe more about dark matter while on Earth.

But even if we would find some naturally occurring such particles around and had instruments that could measure such small gravitational forces, there were no other properties to talk about. It has no color (as it does not interact with photons). It has (to us) no concernable size or extensions, as we cannot interact with any particles with it, except with gravitational force. As it only interacts with gravitation, the only property it interact with us with is its mass. So around 20 pounds is everything we'll ever learn about it.

The oracle proceeds to break expectations by suggesting that Ponytail and Cueball go out for {{w|burrito}}s, something generally considered less than scientific. When faced with the apparent futility of continuing to try to investigate dark matter, the oracle predicts going out for burritos is precisely as productive as any other approach (i.e. "not at all").

When the title text observes that burritos interact through the strong, weak, and electro-magnetic forces in addition to gravity, or all four known {{w|fundamental interaction}}s, it presumably means that they can be seen, smelt, tasted, and their texture sensed, as well as producing digestive effects, and that all of these effects generally tend to be pleasant, hence contributing to their popularity.

==Transcript==
:[Cueball and Ponytail are standing in front of a pentacle with lit candles at the corners. A black sphere, the oracle, is floating above the middle of the pentacle.]
:Ponytail: Dear oracle,
:Ponytail: What is the nature of dark matter?
:Oracle: It's about 20 pounds.

:[Close up of oracle]
:Off-panel: What?
:Oracle: Dark matter is a particle. It weighs about 20 pounds.
:Oracle: It only interacts through gravity.

:[Same view as first panel]
:Cueball: Only gravity, huh?
:Cueball: So none of our experiments are really going to tell us any more about it, then.
:Oracle: Afraid not.

:[Same view as first and third panels, except Cueball lifted his forearm.]
:Cueball: So what do we do?
:Oracle: You should go out for burritos.
:Ponytail: How will that help?
:Oracle: Well
:Oracle: Burritos are pretty good.

{{comic discussion}}<noinclude>
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Physics]]
[[Category:Food]]
</noinclude>