explain xkcd - User contributions [en]

Landing

2023-09-09T22:42:30Z

162.158.74.42: Nyet, tvarisch..

#REDIRECT [[1446: Landing]]

5: Blown apart

2023-09-02T23:41:00Z

162.158.74.42: Undo revision 323186 by IdiosyncraticLawyer (talk)

{{comic
| number = 5
| date = January 1, 2006
| title = Blown apart
| image = blownapart_color.jpg
| titletext = Blown into prime factors
}}

==Explanation==
This comic is a mathematical and technical joke involving prime numbers and primary colors. In the comic, a black-colored ''70'' sees a package, but it turns out to be a {{w|letter bomb}} that explodes when opened. The result is pieces of the number scattered about: a red-colored ''7'', a green-colored ''5'', and a blue-colored ''2''.

The title text explains the logic for splitting 70 into 7, 5, and 2; as with many of the earlier comics, the title text explains the joke rather than adding to it. 7*5*2 is a {{w|prime factorization}} of the number 70. {{w|Prime number|Prime numbers}} are numbers that cannot be divided by any number other than itself and 1. Factors of a number are numbers that can be multiplied together to produce that number (e.g., 2×5×7 = 70). 70 has other factors, including 1, 10, 14, 35, and 70, but 2, 5, and 7 are the only factors that are prime. All other factors of 70 can be formed by choosing zero, two, or three of the prime factors and multiplying them together.

An implication of this comic is that prime numbers would be immune to explosions, as they are already their smallest parts. Although not explicitly called out, the colors of the numbers also seem to have been blown apart. Red, green, and blue are the primary colors in the {{w|additive color}} model. These colors mixed in pairs produce cyan, magenta, and yellow, which are primary colors in the {{w|subtractive color}} model. The removal of all additive primary colors, or conversely, the combination of all subtractive primary colors, produces black, which is the color of the original 70. The comic is somewhat misleading in that red, green, and blue do not compose black in either color model, but the difference between the two models is not widely understood (most still view the additive primaries as red, yellow, and blue).

==Transcript==
:[A black number 70 sees a red package. This small panel is partly overlaid on the next larger panel, which is shifted down.]
:'''70'''
:70: hey, a package!

:[The package explodes in a cloud of brown smoke. This panel is both behind the first in the top left corner, and below the last panel, which has been laid on top of that corner.]
:'''BOOM'''

:[There are a red 7, a green 5, and a blue 2 lying near a scorched mark on the floor.]
:'''7'''
::'''5'''
:'''2'''

==Trivia==
* This comic and [[12: Poisson]] were posted for the first time on the [[:Category:First day on xkcd.com|first day of xkcd.com]]. Both of these comics were exclusively published on [https://xkcd.com xkcd.com] and were never shared on [[LiveJournal]].
* This comic was [[:Category:Sunday comics|released on a Sunday]].

{{comic discussion}}

[[Category:First day on xkcd.com]]
[[Category:Checkered paper]]
[[Category:Comics with color]]
[[Category:Number theory]]
[[Category:Comics with lowercase text]]

2452: Aviation Firsts

2021-04-21T02:17:05Z

162.158.74.42: /* Explanation */

{{comic
| number = 2452
| date = April 19, 2021
| title = Aviation Firsts
| image = aviation_firsts.png
| titletext = Mile High Club membership [✓] [ ] Discovery of parts of Amelia Earhart's skeleton [ ] [ ] Mid-flight incident that results in safe landing on the Hudson River [✓] [ ]
}}

==Explanation==
{{incomplete|Created by D. B. COOPER OF MARS. Put a table detailing all the events of the achievement checklist with an Earth and Mars column. Do NOT delete this tag too soon.}}
This comic reflects the [https://twitter.com/NASAPersevere/status/1384209173924089863 ''Ingenuity'' probe's first flight on Mars]. Now that ''Ingenuity'' has completed its first flight, Mars can be counted among planets with controlled flight.

The previous categories were completed by the first space probes to reach and then land on Mars. Flight, Landing and Controlled Landing were variously achieved by some or all of the prior landers, depending upon your definition of flight, but certainly by the {{w|Mars_Science_Laboratory#Sky_crane_landing|Skycrane}} element used in landing both ''Curiosity'' and ''Perseverance'' rovers. These may not have qualified as Controlled Powered Flight as they only used their power to control the landing, before 'flying off' again under power without any more precise control than that needed to intentionally 'crash elsewhere'.

The remaining have only been completed on Earth, if at all. The {{w|Aerobatic_maneuver|Loop}} does not yet seem to be practical or necessary to attempt over Mars, and the rest grow more bizarre and more specific further down the comic and extending into the title text.

===Cultural references===
* The {{w|Hughes H-4 Hercules}} (the "Spruce Goose") was a prototype wooden airplane, known for being the largest flying boat ever constructed. The Hercules was designed by aviation pioneer (and, latterly, famed recluse) Howard Hughes. The design was intended as a lightweight transoceanic transport for the the military, but the prototype (built out of wood because of aluminium shortages during the 1940s) was not completed until well after the end of the Second World War and only actually flew a single time in 1947. Since 1991, it has been on permanent display at the Evergreen Aviation & Space Museum in McMinnville, Oregon, USA.
* In 1971, Northwest Orient Airlines Flight 305 was famously hijacked by a man who bought a ticket under the pseudonym {{w|D. B. Cooper|"Dan Cooper"}} (but popularly known as D. B. Cooper). After being given a $200,000 ransom by the plane's crew, Cooper then proceeded to parachute jump out of the plane using the rear {{w|airstair}} and was never confirmed to have been heard from again; many experts agree that the parachute jump was very risky and it's unlikely that Cooper even survived. (Cooper was previously mentioned in [[1400: D.B. Cooper]] and [[1501: Mysteries]].)
* The "{{w|mile high club}}" is a slang term for people who have had sexual intercourse while onboard an airplane in flight. Although the notion of {{w|sex in space}} is understood to be severely hampered by the total lack of gravity, it's not known whether Mars's low gravity (compared to Earth) would make it similarly challenging to have intercourse on or near the planet's surface.
* {{w|Amelia Earhart}} was a female aviator who, along with her navigator {{w|Fred Noonan}}, went missing over the Pacific Ocean in 1937 while attempting a global circumnavigation flight and has never been found. While there's some possibility that some of Earhart and Noonan's remains will eventually be discovered somewhere on the Pacific coastline, the notion of them somehow ending up on the surface of Mars is practically impossible outside the remit of certain conspiracy theories. (Earhart was previously mentioned in [[1501: Mysteries]], [[950: Mystery Solved]], and [[2197: Game Show]].)
* The {{w|US Airways Flight 1549|Miracle on the Hudson}} was a 2009 aviation incident in which a US Airways airliner struck a flock of geese shortly after takeoff from LaGuardia Airport in New York City. Despite the plane losing all its engine power as a result of the bird strike, Captain Chesley Sullenberger successfully crash-landed in the nearby Hudson River with minimal injuries to the passengers onboard. Of course, it would be highly impractical for a powered flight that encounters a problem in the sky above Mars to then fly all the way to Earth just for an emergency landing.

==Transcript==
:[A chart is shown with nine items. To the right of each item there are two check boxes. Above the top row of check boxes are two underlined labels for the two columns. The first four rows have both boxes checked, the last five have only the first box checked. The last two items are so long that they take up three and four rows of text. The first seven items can be on one line.]

Earth Mars
Flight <big>[✓]</big> <big>[✓]</big>
Landing <big>[✓]</big> <big>[✓]</big>
Controlled landing <big>[✓]</big> <big>[✓]</big>
Controlled powered flight <big>[✓]</big> <big>[✓]</big>
Loop <big>[✓]</big> <big>[ ]</big>
In-flight meal <big>[✓]</big> <big>[ ]</big>
Planetary circumnavigation <big>[✓]</big> <big>[ ]</big>

Enormous wooden aircraft <big>[✓]</big> <big>[ ]</big>
built by a reclusive billionaire
that flies exactly once

Hijacking by someone dubbed <big>[✓]</big> <big>[ ]</big>
"D.B. Cooper" who demands
money and then jumps out
mid-flight to an unknown fate

{{comic discussion}}
[[Category:Mars rovers]]
[[Category:Charts]]
[[Category:Comics featuring real people]]
[[Category:Sex]]

Talk:1753: Thumb War

2016-10-31T17:31:48Z

162.158.74.42:

I love this new perspective of the comic. Seeing the characters as kids is an interesting concept, especially when one of them is Black Hat. Hopefully more of these kind of comics will come to exist. I wonder what kind of "classhole" tendencies Black Hat had as a kid... --[[User:JayRulesXKCD|JayRulesXKCD]] ([[User talk:JayRulesXKCD|talk]]) 14:38, 31 October 2016 (UTC)

:We also get to see Black Hat as a child in 1139: Rubber and Glue --[[Special:Contributions/172.68.78.124|172.68.78.124]] 15:00, 31 October 2016 (UTC)

Is this really Hairy in the comic or just a young Cueball, just with hair? Note that also Black Hat has visible hair under his hat in this comic, whereas the adult version doesn't have hair (or at least none visible). [[Special:Contributions/162.158.202.141|162.158.202.141]] 14:48, 31 October 2016 (UTC)

:This is Hairy as Hairy is not a single character, but just the name used to identify a stick figure with hair and to distinguish them from a Cueball (a stick figure without hair). The characters with hats are pretty much the only ones assumed to be non-generic recurring characters. Also, Black Hat does have hair, as seen in comic 377: Journal 2 --[[Special:Contributions/172.68.78.124|172.68.78.124]] 15:03, 31 October 2016 (UTC)

I didn't see Hairy's not wanting to play anymore as boredom but as either developing fear, or/and not wanting to play by weird rules he doesn't understand. Trivia; my school yard version didn't have a 5-6-7-8..., our thumb's shook "hands" and bowed to each other before the fight began. ~~[[Cris]] [[Special:Contributions/108.162.245.57|108.162.245.57]] 15:42, 31 October 2016 (UTC)

: Agreed (on both parts). The current description's "…and then counting up by fours and making rhymes" was utterly foreign to me, and I had to read it a few times to make sure it really was implying that it was standard to count above four. I've ''never'' heard of anything beyond "One, two, three, four; I declare a thumb war!" (accompanied by the thumbs touching alternating sides of the "ring"). Unless we can get anyone who can support the claim that counting above 4 (with or without rhymes) is normal or even uncommon, it should probably be expunged. [[Special:Contributions/108.162.215.220|108.162.215.220]] 16:51, 31 October 2016 (UTC)

:I always learned it with two verses, although the second one varied - "1, 2, 3, 4. I declare a Thumb War." and then either "5, 6, 7, 8. Try to keep your thumbs straight." or "5, 6, 7, 8. This'll be a piece of cake." The last word of the second verse was the cue for the fight to begin. --BoomerSooner[[Special:Contributions/162.158.74.42|162.158.74.42]] 17:31, 31 October 2016 (UTC)

Talk:1751: Movie Folder

2016-10-26T19:41:22Z

162.158.74.42:

Quite a wacky comic and it isn't even a Friday. [[Special:Contributions/108.162.210.196|108.162.210.196]] 14:16, 26 October 2016 (UTC)
Ooh, a first draft...
Hoo boy, that last sentence, though... that is in desperate need of some editing [[Special:Contributions/108.162.237.49|108.162.237.49]] 16:00, 26 October 2016 (UTC)
:Small point, but lorem ipsum isn't pseudo-Latin it's from Cicero's de Finibus Bonorum et Malorum (The Extremes of Good and Evil. It's been used since the very early days of printing.[[User:Richardelguru|Richardelguru]] ([[User talk:Richardelguru|talk]]) 16:33, 26 October 2016 (UTC)richardelguru.
::It is, but the "received" lorem ipsum text is pretty garbled, starting with improper word-splitting at the the very beginning. It shouldn't be described as a straight quotation from Cicero. [[Special:Contributions/162.158.74.53|162.158.74.53]] 17:49, 26 October 2016 (UTC)

I'm not sure how to post comments, but I believe it should read 97 previous Titanics sank, if the movie is about the 98th one striking the reef.... User: bsellnow 26 October 2016... {{unsigned ip|108.162.215.126}}
:Regarding your comment that makes sense! On your other Question: To sign a comment just write <nowiki>~~~~</nowiki> after you comment. (Or press the signature button in the icons above to post those four tildes). I have signed your comment with a template for unsigned comments from non-users (based on your IP address). Sign up so you can keep track of your contributions and for real call your self User:bsellnow ;-)--[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 18:30, 26 October 2016 (UTC)
- The 98th ship might not be the first one to hit the reef. "That series gets good when they start hitting the reef created by all the previous wrecks" implies to me that multiple "good" movies have involved hitting the ship-reef and there's no indication that Titanic 98 was the first one to do so. --[[Special:Contributions/162.158.74.42|162.158.74.42]] 19:41, 26 October 2016 (UTC)BoomerSooner

:I saw it, too. And, while Kynde was commenting, I adjusted it... [[User:MAP|MAP]] ([[User talk:MAP|talk]])

Category:Valentines

2016-09-24T18:12:03Z

162.158.74.42:

Comics related to {{w|Valentine's Day}} (celebrated on February 14) and giving Valentines. The only positive comic (up until the year 2015) was the [[543: Sierpinski Valentine]] and all the other except [[62: Valentine - Karnaugh]], is directly negative about this day. Seems [[Randall]] doesn't approve of it much.

All the comics came out on Valentine's Day or on the closest day before that except the first year (2006) with two Valentine comics on both the 10th and the 13th of February

The first to come out on Valentine's Day was in 2007.

Then there where no comic in 2008. However, he did release a very depressing comic in 2008 on the 13th: [[383: Helping]]. And similarly he released a very gross comic in 2011 on the 14th: [[860: Never Do This]]. This could very likely be on purpose giving his possible negative feelings for this day.

Also because he did Valentines comics both the two years in between (2009 on the 13th and 2010 on the 12th), and the year after in 2012 on the 13th.

But since 2012 he has not released a Valentines comic, and there seem to be no relation at all with the comics that are coming out closest to this day, or the ones on either side of this day. The relevant comics are from 2013 February 13th: [[1173: Steroids]], 2014 February 14th: [[1330: Kola Borehole]], 2015 February 13th [[1486: Vacuum]], and 2016 February 11th [[1642: Gravitational Waves]].

[[Category:Comics by date]]
[[Category:Holidays]]
[[Category:Romance]]

374: Journal

2016-08-31T02:08:41Z

162.158.74.42: /* Explanation */

{{comic
| number = 374
| date = January 23, 2008
| title = Journal
| image = journal.png
| titletext = And the journal is filled with all the things I'd say to her if I were nice like you. I burn it when it's full.
}}

==Explanation==
[[Black Hat]] isn't the type of person to keep a journal, so [[Cueball]] is understandably surprised when he sees Black Hat's journal. Black Hat lives up to his reputation though, as it turns out that the journal is just part of a plot to hurt innocent, preferably shy, girls.

He explains his scheme to Cueball, about how he sits in a train and writes in the journal while sitting across from such a girl. His intention is to make eye contact with her, only to look bashfully down. This is construed to make her believe that he is an emotional guy, that is embarrassed, both about writing the journal, but also because she has caught him staring. He also tries to let her believe that he may be interested in her. He is just waiting for her to start smiling, and then he gets to the point of it all. By rolling his eyes at her while giving her a quick glare only to resume writing he attempts to make her feel {{w|Social alienation|alienated}}. Black Hat assumes that this feeling will stay with the poor girl for the rest of they day. The only thing Black Hat gets out of this is the knowledge of having ruined the girls day. As he says ''It's great!''

Cueball thinks Black Hat is sickening. And exclaims that "this is why we can't have nice people". This is probably a reference to the meme [http://knowyourmeme.com/memes/this-is-why-we-cant-have-nice-things This Is Why We Can't Have Nice Things].

Black Hat excuses himself for doing this because it is so easy. He mixes two different concepts together while doing so. {{w|Shooting fish in a barrel}} is an {{w|idiom}}, describing an effortless or simple action, with guaranteed success. So that is easy pleasure. The adding of ''lonely [http://www.urbandictionary.com/define.php?term=angsty angsty]'' makes the fish sound more like teenagers. The girls Black Hat targets are probably best described as ''lonely angsty teenagers'' which may be a way to describe several young people. And they are the easy targets, i.e. the fish in the barrel, for him to shoot. And this is just so easy and so fun that he cannot help himself.

The title text implies that Black Hat actually does write in the journal, filling it with the kind of things a nice guy like Cueball might wish to say to a shy girl. But that is only so he can burn it when it is full, thus again cementing the fact that he is a complete sociopath.

It is clear from the comic that he has already done this several time with great success, but where this comic might be interesting in it self, it was actually only the setup for introducing [[Danish]], whom we meet for the first time in the second installment of the [[:Category:Journal|Journal]] series, of which this comic was just the first. Danish turns out to be a match for Black Hat in every way of the word. If you want to see how Black Hat's scheme worked on Danish, check out [[377: Journal 2]], released the following week after this one.

The whole "[[:Category:Journal|Journal]]" story are:
*[[374: Journal]]
*[[377: Journal 2]]
*[[405: Journal 3]]
*[[432: Journal 4]]
*[[433: Journal 5]]

==Transcript==
:[Cueball picks up book from a table, as Black Hat turns his head towards Cueball while sitting at his desk with his computer.]
:Cueball: Since when do you keep a journal?
:Black Hat: Oh, I pretend to write in it on the train, and wait for a shy-looking girl to sit across from me.

:[Scene change to inside a train wagon with two poles and two rows of seats facing each other across the central pathway. Black Hat writing in his journal is sitting to the right across from Megan to the left who sits with her arm on her handbag standing on the seat next to her. The windows of the train are completely black. The door to the next wagon can be seen at the back of the wagon. Black Hat is telling the story from the previous frame, so the text is written above the two characters but does not belong to the Black Hat in the panel.]
:Black Hat (narrating): I glance up and wait for her to make eye contact, then look down bashfully and, if I can, blush.

:[Scene back to original room with Cueball looking down while holding the journal down, and Black Hat has turned around in his chair to face towards Cueball. Black Hat leans back on the chair with both arms behind him.]
:Black Hat: Then, when I see her start to smile at me, I roll my eyes and hit her with a quick glare, then resume writing.
:Black Hat: The alienation stays with her all day. It's great.

:[Cueball looks at Black Hat who has turned back starting to type on his computer.]
:Cueball: You're sickening. This is why we can't have nice people.
:Black Hat: I can't help it. It's like shooting lonely, angsty fish in a barrel.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Black Hat]]
[[Category:Journal|01]]

564: Crossbows

2016-08-28T00:17:26Z

162.158.74.42: /* Explanation */

{{comic
| number = 564
| date = April 3, 2009
| title = Crossbows
| image = crossbows.png
| titletext = I hate being the slowest guy in the lab.
}}

==Explanation==
There are conflicting theories as to the meaning of this comic.
#Since the experimental confirmation or denial of the {{w|Higgs mechanism}} was widely recognized as important to the development of physics, the experimenters involved were likely to receive Nobel Prizes. Nobel Prizes, however, are only given to living people and groups of up to three in size. The experimenters, therefore, are preparing to fight to the death when the discovery comes. Peter Higgs had [http://www.reuters.com/article/2008/04/07/us-science-particle-idUSL0765287220080407 made a statement] in 2008 hinting that the confirmation would come within one year, and that statement was made one year before the Tuesday mentioned in the comic. Tentative experimental confirmation of the Higgs boson was made in July 2013.
#At the time this was written, there was much hype about the Higgs mechanism, as it was a theory explaining how particles got their masses. Experimental confirmation of the Higgs mechanism and its signature particle (the {{w|Higgs boson}}) was seen with such importance that the boson was dubbed the "God particle". Detecting it, however, required accelerating particles to energies higher than ever before. Since this was at the cutting edge of physics, it was unknown what would actually happen. There were [http://www.theregister.co.uk/2008/09/05/lhc_to_leave_fabric_of_spacetime_continuum_unripped/ fears] that the experiment would create a micro black hole or worse. This comic could be seen as applying those fears to a common trope in horror movies and video games where a mutant infestation is created by unknowing scientists. The scientists here, apart from poor [[Cueball]], have done their research and armed themselves for any upcoming dangers. It is unknown whether these dangers are specific or not. Some argue that [[:Category:Velociraptors|velociraptors]] are a common enough theme in xkcd that the experimenters are preparing for a velociraptor attack. Others point out that the crossbow is a weapon in the game series {{w|Half-Life (video game)|Half-Life}}, whose plot has a similar infestation following failed physical experiment ripping dimensional seams. They mention that someone at the particle accelerator [http://img144.imageshack.us/img144/2131/freemanae8.jpg closely resembled] one of the main characters of Half-Life. Of course, the crossbows may just be a general preparation for danger.
#Finally, this comic may simply be general sympathy for those late to catch on to something. Substituting different things for "crossbow" and "Higgs excitation" would give a similar situation for Cueball. [[Randall]] apparently hates these situations. A layer of {{w|metahumor}} could be present here, as Cueball may represent the clueless readers of xkcd who have to go to the [http://forums.xkcd.com/index.php forum] or [[Main Page|this wiki]] to understand its comics.

The proper interpretation of this comic, or whether there even is one, remains an open question.

==Transcript==
:[Cueball is pulling a crossbow out of a desk.]
:Cueball: Why do you have a crossbow in your desk?
:Megan (off-screen): You ''don't''?

:[Pan to Megan who looks towards Cuball who is off-screen to the left.]
:Cueball (off-screen): No—why would—
:Megan: You ''are'' studying the consequences of Higgs excitation, aren't you?
:Megan: Like the rest of the lab?

:[Cueball, now carying Megan's crossbow joins her as the panel extends to include another Cueball-like guy to her right, he also carries a crossbow.]
:Cueball: Yes, but why—
:Guy: Maybe he's slow with the math.
:Megan: Well, he has until Tuesday.
:Guy: Poor guy.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Multiple Cueballs]]
[[Category:Crossbows]]

1725: Linear Regression

2016-08-28T00:14:44Z

162.158.74.42: /* Explanation */

{{comic
| number = 1725
| date = August 26, 2016
| title = Linear Regression
| image = linear_regression.png
| titletext = The 95% confidence interval suggests Rexthor's dog could also be a cat, or possibly a teapot.
}}

==Explanation==
{{Incomplete|95% interval from the title text may need revising.}}
{{w|Linear regression}} is a method for modeling the relationship between multiple variables. In the simplest case, it can be used for two variables wherein the model determines a "{{w|least squares|best-fit}}" line through a {{w|scatter plot}} of the datasets, together with a {{w|coefficient of determination}}, usually denoted ''r''2 or ''R''2. When only two variables are included in the regression, ''R''2 is merely the square of the correlation between the two variables. ''R''2 is a number between 0 and 1 that indicates how well one variable can be used to predict the value of another. A value of 1 means perfect correlation, while a value close to 0 indicates a weak relationship between the variables.

{{w|Constellation}}s are patterns created by linking the apparent positions of stars. Different civilizations have recognized different constellations (the modern IAU, for example, lists 88 "official" constellations), and one could create their own constellations by connecting assorted points.

In this comic, a set of data has had linear regression and some form of statistical analysis applied to it, indicating that there is low correlation between the two. The data points are so widely scattered that (as noted in the comic) it is easier to connect the data points in a constellation-like pattern than it is to determine whether the correlation is negative or positive (without looking at the trendline, of course). Because of this, [[Randall]] suggests we should be suspicious of any conclusions drawn from this data.

"Rexthor the Dog bearer" seems to be a spoof on Thor, a Norse god who wields a hammer.
By replacing his hammer with a dog and adding "Rex" (an archetypal dog name), Randall creates a comical, dog-bearing version of Thor.

The 95% confidence interval in the title text is a reference to the p-value, where a 5% cutoff is generally accepted as the greatest p-value that is significant.

The cat may be mentioned in the title text simply because cats and dogs often look very similar, especially in cruder drawings that might be made by connecting several points. The teapot may be a reference to [https://en.wikipedia.org/wiki/Russell%27s_teapot Russell's teapot], or possibly to the "teapot" asterism in the constellation Sagittarius.

==Transcript==
:[Two square panels show identical sets of scattered black dots, with only the red additions being different.]

:[The left panel shows a slightly rising red line drawn through the middle of the panel, passing near a few dots but not obviously related to most of them. A red text is below the dots:]
:R2=0.06

:[The right panel shows many of the dots connected by red lines to form a stick figure of a man resembling the constellation Orion, with the hand on the reader's right raised and holding an object. A red text is below the dots:]
:Rexthor, the Dog-Bearer

:[A caption is below and spanning both panels:]
:I don't trust linear regressions when it's harder to guess the direction of the correlation from the scatter plot than to find new constellations on it.

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Scatter plots]]
[[Category:Astronomy]]
[[Category:Animals]]

1061: EST

2016-08-16T21:38:19Z

162.158.74.42: /* Other features */

{{comic
| number = 1061
| date = May 28, 2012
| title = EST
| image = est.png
| titletext = The month names are the same, except that the fourth month only has the name 'April' in even-numbered years, and is otherwise unnamed.
}}

==Explanation==
This comic pokes fun of attempts to "fix" the calendar by making it simpler or more rational, which inevitably result in a system just as complicated. This is an example of the paradox in complexity theory that if you attempt to simplify a system of problems by creating a new system of evaluation for the problems you often have instead made the problem more complex than it was originally.

[[Randall]] advertises his idea for a "Universal Calendar for a Universal Planet". He combines {{w|calendar#Calendars in use|calendar}} definitions with {{w|Time zone|time zone}} definitions. The abbreviation '''EST''' in this comic stands for ''Earth Standard Time'' (hence the title), but it is in itself a joke on the American {{w|Eastern Time Zone|Eastern Standard Time}}. In the rest of the explanation EST refers to the comic's Earth Standard Time!

===Length of year===
Because there are approximately 365.2422 days in a {{w|solar year}}, various calendars use different means to keep the calendar year in sync with the solar year and the seasons. The Julian Calendar, for example, has leap days every four years, giving it an average year length of 365.25 days. The most widely used system is the {{w|Gregorian Calendar|Gregorian Calendar}}, which also has leap days every four years, but skips leap days in years divisible by 100 unless the year is also divisible by 400, the latter additions come from Earth's {{w|axial precession}}. This gives it an average year length of 365.2425 days, which is very close to the length of a solar year (see detailed explanation in this video: ''[https://www.youtube.com/watch?v=82p-DYgGFjI Earth's motion around the Sun, not as simple as I thought]''.

{{w|Calendar reform|Other calendars}} have been proposed, such not counting leap days and special "festival days" as a day of the week, in order to make every date fall on the same day of the week every year.

*At "24 hours 4 minutes", EST days are longer, though there are only 360 of them in the year. The extra 4 minutes over the course of 360 days adds up to one standard day, so Randall's EST calendar would at this point have a year that is 361 standard days long. The 24 hours plus 4 minutes length may be a reference to {{w|sidereal day}}, whose duration is 24 hours ''minus'' 4 minutes.

*Running the clock backwards for 4 hours after every full moon gives 8 additional hours at each full moon, twelve or thirteen times in a year. Because a thirteenth full moon will occur once every 2.7 solar years on average, this modification adds 4.1228 standard days to an EST year, bringing it to 365.1228 days.

*The doubling of the non-prime numbers of the first non-reversed hour after each solstice and equinox is a final, very complicated way to bring Randall's EST year in extremely close sync with the solar year. There are 17 prime numbers between 0 and 59 and 43 non-primes. There are 2 equinoxes and 2 solstices each year, so a total of 4x43 = 172 minutes will occur twice. This brings the average length of Randall's EST year to 365.2422 standard days, equal to the solar year to four decimal places.

===Claimed benefits===
Many of the claimed benefits for the calendar are highly dubious:
*While it is fairly ''simple'' to describe, EST is far from simple to understand or put in practice. Clocks in particular would have to regularly undertake very complicated processes like running backwards or duplicating non-prime minutes.
*EST does appear to be fairly ''clearly defined''.
*EST fails completely to be ''unambiguous''. Following each full moon, four hours occur three times, twice forward and once backward. Several minutes are also duplicated, making times during those periods ambiguous.
*The only way EST is ''free of historical baggage'' is that it breaks free of any sensible bits of historical baggage; it keeps such things as the 30-day month and 12-month year, but adopts a different (and variable) length of day that would make it wildly out of sync with the Earth's day-night cycle.
*EST is ''compatible with old units'', as far as seconds, minutes, and hours are concerned, though not for days, months, or years.
*EST is indeed very ''precisely synced with the solar cycle''. The joke is that this has nothing to do with the day/night cycle or the Earth's yearly orbital cycle; the {{w|solar cycle}} is a period of magnetic fluctuation within the sun, lasting 11 Earth years.
*EST is ''free of leap years'', though some EST years are 8 hours longer than others on account of having an extra full moon.
*A calendar ''amenable to date math'' makes it easy to find the length of time between two dates and times by having standardized periods of time. The complex variability of the length of EST years, days, and hours mean it is only ''intermittently'' amenable to date math, which is to say not at all.

===Other features===
The features of the calendar get increasingly bizarre as the description proceeds:

*The {{w|Epoch (reference date)|Epoch}} for EST is set by reference to the {{w|Julian calendar}}, which was superseded by the {{w|Gregorian calendar}}. The Julian calendar is currently 13 days behind the Gregorian calendar.

*The different zone for the United Kingdom is a reference to 1 yard being equal to 0.9144 meters, a pun on using {{w|imperial units}} instead of the {{w|metric system}}. This has been the joke before in [[526: Converting to Metric]] and is also mentioned in [[1643: Degrees]].

*Randall does not like {{w|Daylight saving time}} (DST) very much, as has been made clear in [[:Category:Daylight saving time|several comics]] both before and after this one. See Narnian time below.

*Narnian time is a reference to the fictitious world of {{w|Narnia (world)|Narnia}} in {{w|CS Lewis|CS Lewis'}} book {{w|The Lion, The Witch and The Wardrobe}} and its sequels. In Narnia, time passes much more quickly than in the real world. You could be in Narnia for several days and only a few minutes would have passed in the real world. However, synchronizing this effect would be impossible because it is not a consistent rate; it fluctuates wildly based on the whims of drama and magic. This and the DST mentioned above should be seen as a pair. Because when a country goes into DST time may not pass, which is basically what happens (more or less) when a child enters into Narnia. Whereas in EST Narnian time is synchronized to normal time, which DST is but for the one hour difference in the real calender. Using the wired Narnian time was used as the plot in the bottom left drawing in [[821: Five-Minute Comics: Part 3]].

*The Gregorian calendar does not include the year "0"; after "1" BC the next year is "1" AD. Randall's invention fixes this according to correct Mathematics, only to reintroduce the problem immediately by arbitrarily omitting the year 1958. The year 1958 is significant because January 1, 1958 is the epoch (time zero) in {{w|International Atomic Time}} (TAI), which is part of the basis for {{w|Coordinated Universal Time}} (UTC). (The main difference is that TAI doesn't add leap seconds.)

*The title text's concept of only naming the fourth month ''April'' in the even numbered years, and then leave it unnamed the other years, may be a reference to the ancient (Pre-Babylonian Exile) [http://www.jewfaq.org/calendar.htm Jewish Calendar], which did not name the months, rather assigning them numbers from 1 to 12 (or 13 in leap years, where an extra month was added instead of an extra day). The names used by Jews today are the names of the Babylonian months, derived from various Babylonian deities or events in Jewish history or on the calendar.

==Transcript==
:[Caption and text above the main panel:]
:xkcd presents
:<big>Earth Standard Time</big>
:(EST)
:A universal calendar for a universal planet
:EST is...
:Simple • Clearly defined • Unambiguous
:Free of historical baggage • Compatible with old units
:Precisely synced with the solar cycle • Free of leap years
:Intermittently amenable to date math

:[A list of the details concerning EST:]
:Units
:{|
|-
| style="text-align:right;" | Second:
| 1 S.I. second
|-
| style="text-align:right;" | Minute:
| 60 seconds
|-
| style="text-align:right;" | Hour:
| 60 minutes
|-
| style="text-align:right;" | Day:
| 1444 minutes (24 hours 4 minutes)
|-
| style="text-align:right;" | Month:
| 30 Days
|-
| style="text-align:right;" | Year:
| 12 months
|}

:Rules
:For 4 hours after every full moon, run clocks backward.
:The non-prime-numbered minutes of the first full non-reversed hour after a solstice or equinox happen twice.

:{|
|-
| style="text-align:right;" | Epoch
|    
| Time Zones
|-
| style="text-align:right;" | 00:00:00 EST
|
| The two EST time zones are
|-
| style="text-align:right;" | January 1, 1970 = 00:00:00 GMT
|
|   ''EST'' and ''EST (United Kingdom)''
|-
| style="text-align:right;" | January 1, 1970 (Julian calendar)
|
| These are the same except that the UK second is 0.9144 standard seconds
|}

:{|
|-
| style="text-align:right;" | Daylight saving:
| Countries may enter DST, but no time may pass there.
|-
| style="text-align:right;" | Narnian Time:
| Synchronized✔
|-
| style="text-align:right;" | Year Zero:
| EST ''does'' have a year 0. (However, there is no 1958.)
|}

{{comic discussion}}

[[Category:Time]]
[[Category:Daylight saving time]]
[[Category:Astronomy]]

929: Speculation

2016-08-15T23:43:18Z

162.158.74.42: /* Explanation */

{{comic
| number = 929
| date = July 25, 2011
| title = Speculation
| image = speculation.png
| titletext = 'I was pretty good at skeet shooting, but was eventually kicked off the range for catching the clay pigeons in a net and dispatching them execution-style.'
}}

==Explanation==
During a {{w|basketball}} game, the players discuss the nature of universal conformity. {{w|Facebook}} and {{w|Google+}} are competing {{w|social networks}}, at the time of this comic many people were switching to Plus over Facebook leading many to speculate that Facebook was in decline and that Plus would soon be the dominant social network.

The two players seem to have a disagreement over this. One player states that it would be ridiculous to expect everyone to move to Plus. The other player denies the notion that they have to, valuing his personal preference over conformity. He supports this by saying that his mother still uses {{w|AOL}} and other people continue using {{w|IRC}}, if each time a new dominant social network emerged and everyone switched to it neither of these things would stick around.

They are interrupted when they pass the ball to [[Black Hat]] who immediately shoots it with a crossbow bolt. Their arguments and rather intelligent discussion are derailed by the absurdity of Black Hat's reaction which is both humorous and puts the issue in stark contrast.

Black Hat neither joins in the discussion nor does he participate in the game and it seems that any offer to participate in either is met with a blunt and clear denial. He is simply not a conformist.

In the title text Black Hat continues to provide an example of his tendency to play by his own rules. A clay pigeon is a clay disc that is thrown into the air and serves as a target on a {{w|skeet shooting}} range. Participants are expected to shoot the pigeons with a shotgun but Black Hat would rather capture the clay pigeons and shoot them from a very close range. This is made even more humorous by the excellent crossbow skills he shows in the comic. This practice eventually got him expelled from the shooting range.

==Transcript==
:[Two Cueball-like guys are playing basketball. The right guy (Cueball) attempts to throw the basketball through the hoop, but it bounces off down to his friend. To the right Black Hat has his back to the other two while he is looking at his phone.]
:Friend: Do you seriously think ''everyone'' will move to Plus? It was hard enough getting them on Facebook.

:[The friend has caught the rebound and now passes the basketball back to Cueball. Black Hat is not shown.]
:Cueball: Do they have to?
:Cueball: My mom still uses AOL—it doesn't mean my social life has to happen there.

:[Only Cueball is shown. He passes the basketball to the right towards the off-pannel Black Hat.]
:Cueball: Universal adoption isn't everything. I mean, IRC is still—

:[Zoom in on the basketball as an arrow pierces the ball.]
:''Thunk''

:[Cueball looks to Black Hat who has a crossbow in one hand, he is still looking at the phone in his other hand. The ball with the arrow lies between them.]
:Cueball: You're not really the "catch" type, are you?
:Black Hat: I am not.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Black Hat]]
[[Category:Multiple Cueballs]]
[[Category:Social networking]]
[[Category:Basketball]]
[[Category:Crossbows]]
[[Category:Sport]]