explain xkcd - User contributions [en]

Talk:914: Ice

2020-02-29T00:13:08Z

162.158.63.214: I don't think this is Danish.

Well, at least he didn't lose his spleen. '''[[User:Davidy22|{{Color|#707|David}}y²²]]'''[[User talk:Davidy22|<tt>[talk]</tt>]] 01:30, 17 April 2013 (UTC)

I understood the AAA-Club as reference to him shouting AAAAA. I think that is something pretty common in his situation. --[[Special:Contributions/162.158.91.189|162.158.91.189]] 20:25, 26 February 2016 (UTC)

lol why would Danish need to harvest his ice anyway? And where the hell did she get a bathtub full of kidneys and an AAA membership? [[Special:Contributions/108.162.215.249|108.162.215.249]] 22:31, 1 August 2016 (UTC)
:Yeah she should donate those. [[User:SilverMagpie|SilverMagpie]] ([[User talk:SilverMagpie|talk]]) 17:36, 1 December 2016 (UTC)

I don't think this is Danish. The hair is a little different, and this situation makes more sense if she is a stranger than someone Beret Guy knows. [[Special:Contributions/162.158.63.214|162.158.63.214]] 00:13, 29 February 2020 (UTC)

Talk:38: Apple Jacks

2020-01-25T19:14:09Z

162.158.63.214:

First.
: Second

2254: JPEG2000

2020-01-13T23:09:37Z

162.158.63.214: Basic explanation of the comic.

{{comic
| number = 2254
| date = January 13, 2020
| title = JPEG2000
| image = jpeg2000.png
| titletext = I was actually a little relieved when I learned that JPEG2000 was used in the DCI digital cinema standard. I was feeling so bad for it!
}}

==Explanation==
{{incomplete|Created by a BADLY COMPRESSED IMAGE. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
JPEG2000 is an image standard created in 2000 to improve on the JPEG standard. At this point it continues to have only really been implemented by Apple operating systems. Its adoption may have been slowed by patent concerns.
The people in the comic seem to have some desire for JPEG2000 adoption, and may have been involved in its creation, and seem to care more about its eventual use than rapid adoption.

The core concept of this comic may be about how engineers often expect that a superior technology or standard will catch on, though often other factors keep an "inferior" standard dominant. (See various comics referencing Dvorak keyboards.)

==Transcript==
:[Cueball and another woman are both at a table, facing each other, both working on their own respective computers.]

:[Cueball leans back and stops typing. The woman continues to type.]

:[Cueball looks over at the woman.]
:Cueball: I'm starting to worry that JPEG 2000 isn't catching on as fast as we expected.
:Woman:: Don't worry! We're in this for the long haul.

{{comic discussion}}

2103: Midcontinent Rift System

2019-11-15T15:52:08Z

162.158.63.214: /* Explanation */

{{comic
| number = 2103
| date = January 25, 2019
| title = Midcontinent Rift System
| image = midcontinent_rift_system.png
| titletext = The best wedge issue is an actual wedge.
}}

==Explanation==

Recently, USA politics has caused polarization of the public.<ref>[https://news.gallup.com/opinion/polling-matters/215210/partisan-differences-growing-number-issues.aspx Partisan Differences Growing on a Number of Issues]</ref> It is said to be “split” in two camps (liberal, mostly loyal to the Democratic Party and conservative, mostly loyal to the Republican Party). Here [[Black Hat]] is trying to get elected to some sort of federal office in the {{w|2020 United States elections|at the time upcoming 2020 elections}} by promising he will actually split America in two. His presentation illustrates, using a giant crowbar, the completion of the {{w|Midcontinent Rift System|Midcontinent Rift}}, which is a large crack that started to form about 1.1 billion years ago, but failed to completely sever the continent.

It is unclear why anyone would vote for such a thing, but people directly affected (the Midwest) are likely to vote against [[Black Hat]]. While Black Hat and his campaign advisor [[Ponytail]] speak of weakness in the Midwest, they are talking about two different things: Black Hat refers to the physical weakness of the North American Plate in the Midwest due to the geological rift which he thinks could be exploited by a large enough crowbar, while Ponytail is referring to a political weakness for Black Hat’s campaign in the Midwest due to the likely-unpopular proposal (different regions of the US have different voters and populations who have different priorities and stances, so candidates and their campaigns’ platforms will likely be more popular in some regions and less popular in others). In this case a successful or attempted completion of the rift would likely result in the destruction of millions of houses, buildings, and other man-made structures, not to mention the deaths of many humans (if proper evacuation were not fully implemented and enforced) as well as millions of animals that could not be evacuated. The proposal would also cause huge economic impacts; the Midwest produces a significant proportion of America’s food supplies and hosts important economic centres, such as Chicago and Cleveland. So the popularity among those directly or even indirectly affected is likely quite low. The successful passing of a highly destructive measure such as this would generally involve more direct and overwhelming compensation of the many interests that would otherwise be harmed, to incentivize them to vote against their present livelihood.

The title text is a pun. A {{w|wedge issue}} is a controversial issue which splits apart a demographic group. It is often introduced to create controversy within an opponent’s base so that if the opponent takes any position on the issue, half the voters will desert the opponent. Here the joke is that the “wedge issue” is an actual wedge to split apart the United States.

==Transcript==

:[A map of North America shows the Midcontinent Rift System as a red line curving through the Great Lakes and down through the midwestern United States.]
:1.1 billion years ago, the North American continent began to split in half.

:[Black Hat stands at a lectern with a "Vote 2020" sign on it. He gestures to an image of the globe with a giant crowbar inserted in the rift with an arrow indicating applying pressure to widen the rift.]
:Black Hat: We don’t know why it stopped. If elected, I vow to ''finish'' the job. Thank youl.

:[Ponytail, Black Hat, Megan, and Cueball walk to the right away from a set of stairs. Cueball is looking at a phone and Ponytail is looking at a device or paper with writing on it.]
:Ponytail: Great job up there.
:Black Hat: Thanks! How are my polling numbers?
:Ponytail: Well, I’m seeing some weakness in the Midwest.
:Black Hat: So am I. So am I.
{{comic discussion}}
[[Category:Comics with color]]
[[Category:Comics featuring Black Hat]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]
[[Category:Elections]]
[[Category:Maps]]

2101: Technical Analysis

2019-01-21T05:33:18Z

162.158.63.214:

{{comic
| number = 2101
| date = January 21, 2019
| title = Technical Analysis
| image = technical_analysis.png
| titletext = "I [suspect] that we are throwing more and more of our resources, including the cream of our youth, into financial activities remote from the production of goods and services, into activities that generate high private rewards disproportionate to their social productivity. I suspect that the immense power of the computer is being harnessed to this 'paper economy', not to do the same transactions more economically but to balloon the quantity and variety of financial exchanges." --James Tobin, July 1984
}}

==Explanation==
{{incomplete| Comic is still undergoing TECHNICAL ANALYSIS (this is just the prologue). Do NOT delete this tag too soon.}}

Technical analysis is field which attempts to study stocks on the stock market statistically, seeking to profit off of the patterns that are found there. It is not clear that this is a good way to accomplish anything.

The comic displays a stock price chart, annotated with labels which purport to be technical analysis. These labels are nonsense: "allegro" (a musical term), "lumbar support" (the thing in a chair that supports your back), "bathtub". One label celebrates that "these two points define a line! Promising signal." (In Euclidian geometry, any two points define a line.)

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

{{comic discussion}}

2101: Technical Analysis

2019-01-21T05:30:52Z

162.158.63.214: Technical analysis is field which attempts to study stocks on the stock market statistically, seeking to profit off of the patterns that are found there. It is not clear that this is a good way to accomplish anything.

{{comic
| number = 2101
| date = January 21, 2019
| title = Technical Analysis
| image = technical_analysis.png
| titletext = "I [suspect] that we are throwing more and more of our resources, including the cream of our youth, into financial activities remote from the production of goods and services, into activities that generate high private rewards disproportionate to their social productivity. I suspect that the immense power of the computer is being harnessed to this 'paper economy', not to do the same transactions more economically but to balloon the quantity and variety of financial exchanges." --James Tobin, July 1984
}}

==Explanation==
{{incomplete| Comic is still undergoing TECHNICAL ANALYSIS. Do NOT delete this tag too soon.}}

Technical analysis is field which attempts to study stocks on the stock market statistically, seeking to profit off of the patterns that are found there. It is not clear that this is a good way to accomplish anything.

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

{{comic discussion}}

1292: Pi vs. Tau

2019-01-10T00:13:02Z

162.158.63.214: /* Trivia */

{{comic
| number = 1292
| date = November 18, 2013
| title = Pi vs. Tau
| image = pi vs tau.png
| titletext = Conveniently approximated as e+2, Pau is commonly known as the Devil's Ratio (because in the octal expansion, '666' appears four times in the first 200 digits while no other run of 3+ digits appears more than once.)
}}

==Explanation==
This is yet another of [[Randall]]'s [[:Category:Compromise|compromise comics]]. A few mathematicians argue as to whether to use pi, which is the ratio between a circle's circumference and its diameter, or tau, which is the ratio between a circle's circumference and its radius.

Some consider pi to be the wrong convention and are in favor of using tau as ''the'' circle constant; see the [http://tauday.com/tau-manifesto Tau Manifesto], which was inspired by the article "[http://www.math.utah.edu/~palais/pi.html Pi is wrong!]" by mathematician Robert Palais. Others consider proponents of tau to be foolish and remain loyal to pi (see the [http://www.thepimanifesto.com Pi Manifesto]). Of course, regardless of which convention is used, the change is merely in notation — the underlying mathematics remains unaltered. Still, the choice of pi vs. tau can affect the clarity of equations, analogies between different equations, and how easy various subjects are to teach.

Most people know π (pi) by the approximation 3.14, but do not know τ (tau) which, by definition, is twice as large as pi. Randall is suggesting using "pau", which is a {{w|portmanteau}} of "pi" and "tau", as a number situated, appropriately enough, halfway between pi and tau, i.e. 1.5 pi or 0.75 tau. But of course his number would be inconvenient, as this value does not naturally turn up when working with circles or other mathematical constructs, so there are no commonly used formulas that would use pau.

The title text claims that pau can be approximated by e+2, as both values are roughly 4.71 — a similarity that holds little since it requires another irrational constant, {{w|E (mathematical constant)|e}} (although knowing the value of pau is somewhat more helpful in remembering e to 2 digits). It also attributes the nickname "Devil's Ratio" to pau, due to the sequence {{w|Number of the Beast|666}} supposedly appearing four times in the first 200 digits of pau when expressed in the {{w|octal}} base. However, this is not the case, and was likely due to an error in the computer system used by WolframAlpha; for more details see below.

==Transcript==
:[On the left is a "forbidden"-style slashed circle with the π symbol, captioned "Pi". On the right is a "forbidden"-style slashed circle with 2π, captioned "Tau". Between these is 1.5π, captioned "Pau".]
:A compromise solution to the Pi/Tau dispute

==Math details==
Possibly, [[Randall]] used [http://www.wolframalpha.com/ Wolfram|Alpha] to calculate the result (he uses it a lot, for example [http://what-if.xkcd.com/70/ What-if 70: The Constant Groundskeeper] or [http://what-if.xkcd.com/62/ What-if 62: Falling With Helium]).
However, when the comic was published, there was a bug in Wolfram|Alpha so that, when getting 200 octal digits from "pau", it just calculates the decimal value rounded to 15 significant digits (this is 4.71238898038469) and expands that as octal digits as far as needed.

This gives a periodically repeating number. In the first 200 digits of the octal expansion, the sequences 666 and 6666 do occur, twice and once, respectively. There are 4 occurrences, however, in the first three hundred and ten (310 in base 8 equals 200 in base 10) digits:
<pre>
4.554574376314416445676661714336617116240444076666510533533077631151350452060436452476274022621206136310000177621674175071262255702044274154476005744176002676623042402346036604733130522524127534777714554305412763636566643022106616734723661726160312772574551366370203115523402704104015532221722772357666</pre>
Expansion that long indeed does contain 666 (the {{w|Number of the beast|number of the beast}}) four times (with one instance as 6666). It also contains 0000, 222, 444, and 7777, but they only appear once in a run.

In the first 500 digits of the actual octal expansion of pau, we also find that 6666 occurs once, and 666 occurs two other times:
<pre>
4.55457437631441644323623451447505012242547157301565031476335452700304316771261165505467475703133125234035147165764643331727311243102010764472707236245737216402204376521550655442201431161557425156344621363625174410110777026111560241174471252241762037163367420573533032164702576626667446275343255043345060027305171025475041452166612112500275317166412767657355633417212140135534536541060452450664011414377406267077573054507036064406511117752700327100355213521015136220621644573043264505244325316526666260</pre>
(Note that this contains 500 digits after the decimal point.) No other run of 3 or more repeated digits (e.g. 111) occurs as many times, although 1111 occurs once, 111 occurs once elsewhere, and 333 and 777 also occur once each. 9 other strings of 3 digits occur 4 times, namely 164, 362, 521, 644, 432, 730, 43, 216, and 450, and only 573 occurs more often, as it occurs 6 times. Therefore, if 6666 is counted as two occurrences of 666, it is actually the joint second most common string of three numbers in the first 500 digits.

{{w|Mathematical coincidence|Coincidentally}}, e+2 is also very similar to 1.5 pi, although only to a few digits.
<pre>
1.5π = 4.71238898038...
e+2 = 4.71828182845...
</pre>

==Trivia==
*For Pi the sequence '666' occurs for the first time at position 2440. Many more occurrences can be found here: [http://www.angio.net/pi/ The Pi-Search Page].
*Note that "pau" is Catalan for peace, which might be a good solution for the pi/tau dispute; but Tahitian for peace is "tau", so (appropriately?) around again.
*Also, note that "pau" is the portuguese word for "stick", as well as, in brazilian portuguese, a very common slang for "penis". This may add to the humour (although childishly) for portuguese-speaking readers, though it is fair to presume that it was not Randall's intention to do so.
*In the discussion it has been theorized that Randall used [[356: Nerd Sniping|Nerd Sniping]]. In which case he was aware of the mistake in Wolfram!
*For an entertaining introduction to the concept of tau, see this [https://www.khanacademy.org/math/recreational-math/vi-hart/pi-tau/v/pi-is--still--wrong Vi Hart video].
*In March 2018 the video [https://www.youtube.com/watch?v=bcPTiiiYDs8 How pi was almost 6.283185...] was released on why Pi could just as well have been Tau (6.28), since {{w|Leonhard Euler|Euler}}, who used the letter Pi in his books, used it for both what we call Pi and Tau today... This very comic is also briefly shown in a segment regarding the controversy about these two versions of "Pi".
*Finally, "pau" means "finished" in Hawaiian.

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Math]]
[[Category:Compromise]]

Talk:2093: Reminders

2019-01-03T13:33:20Z

162.158.63.214:

I added an explanation in which I extended Cueball's reaction from the reminders to Randall himself - I believe this is commonly done for many comics, but please feel free to modify it. [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 17:25, 2 January 2019 (UTC)

Relevant SMBC: https://www.smbc-comics.com/comic/gmail [[Special:Contributions/162.158.63.214|162.158.63.214]] 13:33, 3 January 2019 (UTC)

Talk:2087: Rocket Launch

2018-12-19T20:27:46Z

162.158.63.214:

I had to fight the urge to type Care Bare [[User:Arachrah|Arachrah]] ([[User talk:Arachrah|talk]])

This was published during the Arianespace launch livestream, between launch and satellite deployment: https://www.youtube.com/watch?v=mpHJoo0h8GQ [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 17:11, 19 December 2018 (UTC)

Looks like it could be an Ariane5 in the comic, it is a 3 stage. Anyone know if Max-CB is a real thing (and before I get any wisecracks, I know there aren't any Care Bears in the clouds) [[Special:Contributions/162.158.63.214|162.158.63.214]] 20:27, 19 December 2018 (UTC)

r/shittyspacexideas --[[Special:Contributions/173.245.52.139|173.245.52.139]] 19:53, 19 December 2018 (UTC)

2084: FDR

2018-12-12T15:15:31Z

162.158.63.214: /* Transcript */

{{comic
| number = 2084
| date = December 12, 2018
| title = FDR
| image = fdr.png
| titletext = June 21st, 365, the date of the big Mediterranean earthquake and tsunami, lived in infamy for a few centuries before fading. Maybe the trick is a catchy rhyme; the '5th of November' thing is still going strong over 400 years later.
}}

==Explanation==

The United States Naval base at Pearl Harbor was [https://en.wikipedia.org/wiki/Attack_on_Pearl_Harbor attacked in 1941], and is credited with starting the United States' involvement in World War II. The then US president, [https://en.wikipedia.org/wiki/Franklin_D._Roosevelt Franklin D. Roosevelt], issued a speech to the American people which begins with the line "December 7th, 1941. [https://en.wikipedia.org/wiki/Infamy_Speech A date which will live in infamy...]". Whenever Randall writes "December" he feels compelled to complete the line, a mistake which is visible in this comic.

The title text refers to the [https://en.wikipedia.org/wiki/365_Crete_earthquake 365 Crete earthquake], a historical earthquake with a magnitude of at least 8.0 which caused widespread destruction across the Eastern Mediterranean; and to [https://en.wikipedia.org/wiki/Guy_Fawkes_Night Guy Fawkes Night], the anniversary of the famous failed attempt to bomb Parliment on the night of November 5th, 1605. The later event is immortalized in the rhyme "remember remember, the fifth of November, the gunpowder, treason, and plot", the former event less so.
The Mediterranean earthquake and tsunami destroyed the mycenan civilisation and possibly led to the myth of atlantis.

==Transcript==
:[Close-up of a form]
:[Name:] Randall Munroe
:Date: Dec <s>7, 19–</s> 12, 2018
:Country: United States

:[Caption below the frame:]
:FDR was so good at speeches, that I spend a whole month each year writing the date wrong.

{{comic discussion}}

2084: FDR

2018-12-12T15:14:39Z

162.158.63.214: /* Transcript */

{{comic
| number = 2084
| date = December 12, 2018
| title = FDR
| image = fdr.png
| titletext = June 21st, 365, the date of the big Mediterranean earthquake and tsunami, lived in infamy for a few centuries before fading. Maybe the trick is a catchy rhyme; the '5th of November' thing is still going strong over 400 years later.
}}

==Explanation==

The United States Naval base at Pearl Harbor was [https://en.wikipedia.org/wiki/Attack_on_Pearl_Harbor attacked in 1941], and is credited with starting the United States' involvement in World War II. The then US president, [https://en.wikipedia.org/wiki/Franklin_D._Roosevelt Franklin D. Roosevelt], issued a speech to the American people which begins with the line "December 7th, 1941. [https://en.wikipedia.org/wiki/Infamy_Speech A date which will live in infamy...]". Whenever Randall writes "December" he feels compelled to complete the line, a mistake which is visible in this comic.

The title text refers to the [https://en.wikipedia.org/wiki/365_Crete_earthquake 365 Crete earthquake], a historical earthquake with a magnitude of at least 8.0 which caused widespread destruction across the Eastern Mediterranean; and to [https://en.wikipedia.org/wiki/Guy_Fawkes_Night Guy Fawkes Night], the anniversary of the famous failed attempt to bomb Parliment on the night of November 5th, 1605. The later event is immortalized in the rhyme "remember remember, the fifth of November, the gunpowder, treason, and plot", the former event less so.
The Mediterranean earthquake and tsunami destroyed the mycenan civilisation and possibly led to the myth of atlantis.

==Transcript==
[Close-up of a form]
[Name:] Randall Munroe
Date: Dec <s>7, 19–</s> 12, 2018
Country: United States

[Caption below the frame:]
FDR was so good at speeches, that I spend a whole month each year writing the date wrong.

{{comic discussion}}

2084: FDR

2018-12-12T15:08:05Z

162.158.63.214: /* Explanation */ Explain title text (sorry, I was writing this at the same time as you and I think my version has more citations and such)

{{comic
| number = 2084
| date = December 12, 2018
| title = FDR
| image = fdr.png
| titletext = June 21st, 365, the date of the big Mediterranean earthquake and tsunami, lived in infamy for a few centuries before fading. Maybe the trick is a catchy rhyme; the '5th of November' thing is still going strong over 400 years later.
}}

==Explanation==

The United States Naval base at Pearl Harbor was famously [https://en.wikipedia.org/wiki/Attack_on_Pearl_Harbor attacked in 1941], and is credited with starting the United States' involvement in World War II. The then US president, [https://en.wikipedia.org/wiki/Franklin_D._Roosevelt Franklin D. Roosevelt], issued a famous speech to the American people which begins with the line "December 7th, 1941. [https://en.wikipedia.org/wiki/Infamy_Speech A date which will live in infamy...]". This speech is one of the most famous speeches in history, the opening line especially so, and whenever Randall writes "December" he feels compelled to complete the line, a mistake which is visible in this comic.

The title text refers to the [https://en.wikipedia.org/wiki/365_Crete_earthquake 365 Crete earthquake], a historical earthquake with a magnitude of at least 8.0 which caused widespread destruction across the Eastern Mediterranean; and to [https://en.wikipedia.org/wiki/Guy_Fawkes_Night Guy Fawkes Night], the anniversary of the famous failed attempt to bomb Parliment on the night of November 5th, 1605. The later event is immortalized in the rhyme "remember remember, the fifth of November, the gunpowder, treason, and plot", the former event less so.
The Mediterranean earthquake and tsunami destroyed the mycenan civilisation and possibly led to the myth of atlantis.

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

{{comic discussion}}

2084: FDR

2018-12-12T15:02:12Z

162.158.63.214: Add initial explanation

2079: Alpha Centauri

2018-12-03T19:00:13Z

162.158.63.214:

{{comic
| number = 2079
| date = November 30, 2018
| title = Alpha Centauri
| image = alpha_centauri.png
| titletext = And let's be honest, it's more like two and a half stars. Proxima is barely a star and barely bound to the system.
}}

==Explanation==
{{incomplete|Created by a SOLAR SAIL. It would be good to enumerate similar projects. Do NOT delete this tag too soon.}}
{{w|Alpha Centauri}} is the closest star system to our solar system, being 4.37 {{w|light-year}}s away. As such, there are numerous ongoing plans and projects to journey to, and explore the star system, especially since the exoplanet {{w|Proxima Centauri b}} was found in 2016 to possibly have liquid water oceans and a very thin atmosphere. Ponytail announces such a project using a {{w|Voyager program|Voyager}}-like probe.

However, an offscreen person is against her idea, based on her opinion that "Alpha Centauri sucks". The person says that they looked "online" and that the system "only has three stars". This is a pun playing on the stars used in online reviews and stars in the solar system.

===Star Rating Systems===
Online rating systems, such as {{w|Yelp}}, often use {{w|Star (classification)|star rating system}}s, with more stars indicating higher quality, up to an arbitrary maximum, such as five stars to indicate the best rating. Due to [https://www.explainxkcd.com/wiki/index.php/937:_TornadoGuard the nature of 5 star rating systems], [https://www.explainxkcd.com/wiki/index.php/1098:_Star_Ratings anything scoring less than 4 out of 5 in a 5 star rating system is crap]; and in a 10-star rating system, scoring a mere 3 stars out of a possible 10 stars would be ''exceedingly'' low quality. The Alpha Centauri star system has 3 ''physical'' {{w|star}}s: Alpha Centauri A, Alpha Centauri B, and Proxima Centauri. The offscreen person has misconstrued this fact of the system as some kind of review.

A previous comic, [[1098: Star Ratings]], points out that star ratings below 4 out of 5 tend to be seen as "crap".

The title text furthers the pun. Some online star rating systems also allow partial stars, such as a half-star, to allow more precision in rating (e.g. rating 2.5 stars instead of being forced to chose 3 stars or 2 stars), or display an average collective rating as partial stars (e.g. showing 2.5 stars when five people have rated 3 stars and five people have rated 2 stars). Alpha Centauri's "half star" refers to Proxima Centauri, a {{w|red dwarf}}, which is a type of low-mass star. According to the offscreen person, this barely qualifies it to be a star. Furthermore, Proxima Centauri is nearly 13,000 AU (0.21 light years) away from the other 2 stars in the system, so it was long unknown whether Proxima Centauri was gravitationally bound to the Alpha Centauri star system.

===Calculations===
All numbers are rounded after subsequent calculations.

According to [https://www.space.com/41447-parker-solar-probe-fastest-spacecraft-ever.html space.com] the fastest spacecraft ever will be the Parker Solar Probe which will reach 430,000 mph (692,000 km/h) as it reaches its closest point orbiting the sun. This is just over half of 1% of the needed speed of the Alpha Centauri vehicle proposed in the comic. The Voyager 1 spacecraft, launched in 1977, is currently traveling at about 38,000 mph (61,000 km/h).

Distance to Alpha Centauri system = 4.367ly

4.367 light years / 35 years = 0.12477ly per year

0.12477 light years/year * 5.879e+12 miles/light year = 733,484,000,000 miles/year

733,484,000,000 miles/year / 365 days/year / 24 hours/day = 83,000,000 Miles/hour / 1.60934 miles/kilometer = 134,000,000 Kilometers/hour

The above math assumes a constant speed, and requires a speed of ~0.124855c. Assuming a constant acceleration from rest (non-relativistic math follows):

35*365.25*24*60*60 = 1.10e+9 seconds in 35 years

4.367 * 5.879e+12 = 2.57e+13miles, 4.13e+13 km, 4.13e+16 m.

x = 1/2*a*t2

a = 2*x*t -2

Assuming constant acceleration to the halfway point and constant deceleration to the destination, (otherwise you streak through the system, barely observing anything):

ttrip = 2*thalfway

a = 2*2.06e+16*(5.50e+8) -2 = 0.136 m/s2, roughly 1/80 gravity.

vhalfway = a*thalfway.

Top Speed: 75,000,000 m/s ~ 1/4*c.

Assuming E = F*d, 0.136*1*4.13e+16 = 5.37e15 Joules will be required for each kilogram carried to Alpha Centauri in 35 years.

This would require an unimaginable amount of mass for a conventional chemical rocket, and is a completely impractical power requirement for any sort of passive solar sail concept.

Further, the top speed is fast enough to require a recalculation using relativistic physics to model the problem. This means that the energy budget will need to increase, as the relativistic mass of the probe will increase, requiring more force (and thus more energy) to accelerate and decelerate near its top speed than this calculation returns.

[https://en.wikipedia.org/wiki/Breakthrough_Starshot Active], laser based propulsion methods require currently non-existent and purely specualtive laser and materials technologies, as well as a powerplant equivalent to 12,500 of the [https://www.power-technology.com/features/feature-largest-nuclear-power-plants-world/ World's Largest Nuclear Plant] to transport sub-gram masses on this timescale. This also assumes that any probes can be steered accurately enough across interstellar distances to come close enough to image with any resolution the bodies they will be passing at a non-trivial fraction of c.

Short of FTL travel or near-perfect mass-energy conversion technology, transporting more than a fraction of a gram of material to Alpha Centauri in a human lifetime will be unachievable. Short of an enormous breakthrough in power generation, transporting even a fraction of a gram is impossible.

Nonetheless, [http://breakthroughinitiatives.org/challenges/3 Breakthrough Starshot] is attempting to send many gram-sized probes to Alpha Centauri within the century. Following current technological trends, they expect the efficiency of laser-based propulsion to increase by launch time, allowing launches driven by an unreasonably-large-but-achievable amount of power. The top speed needed is halved by refraining from slowing at all at the destination: the probes will aim a distance away from the target, so that it traverses by slowly enough for a camera to rotate and track it, even at near-light speeds. To account for error and space dust, the plan is to launch many tiny probes simultaneously. They may only be able to accomplish their goal if they can get enough funding to actually affect the global economy enough to make the technologies they require more efficient to produce. Launches would additionally burn incredible quantities of natural gas.

==Transcript==
:[Ponytail stands on a podium giving a presentation in front of a slide with an image of a [https://wikipedia.org/wiki/Voyager_1 Voyager-like] spacecraft.]
:Ponytail: Our probe can reach Alpha Centauri in under 35 years.
:Offscreen voice: We should go somewhere else. Alpha Centauri sucks.
:Ponytail: Huh? It's the closest, most convenient system!
:Offscreen: Yeah, but I checked online and it only has three stars.

{{comic discussion}}

[[Category:Comics featuring Ponytail]]
[[Category:Space probes]]
[[Category:Online reviews]]
[[Category:Puns]]

2053: Incoming Calls

2018-10-01T16:51:13Z

162.158.63.214: Explanation of alt text

{{comic
| number = 2053
| date = October 1, 2018
| title = Incoming Calls
| image = incoming_calls.png
| titletext = I wonder if that friendly lady ever fixed the problem she was having with her headset.
}}

==Explanation==
{{incomplete|Please edit the explanation below and only mention here why it isn't complete. Do NOT delete this tag too soon.}}
This comic shows a graph of incoming phone calls over time, which Randall also labels as "why I finally stopped picking up for unknown numbers".

Over time, Randall's friends and family have been less likely to make phone calls to him, likely due to the use of text messages and other messaging apps. Additionally, although there was a large percentage of phone calls from legal telemarketers in the 1990s, this percentage has significantly dropped, most likely due to the creation of the {{w|National Do Not Call Registry}}. Instead, there has been a rise in phone calls from {{w|Phone fraud|scammers}} and political advertisements. It is implied that the latter two groups have caused Randall to stop answering the phone for unknown numbers.

The alt text is a reference to a scam where the line would be silent, followed by a recording of a woman saying she was having trouble with her headset and then asking "Can you hear me now?" This was allegedly an attempt to record the target's voice saying "yes" and then using it to claim the target had agreed to a purchase.

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

{{comic discussion}}

2048: Curve-Fitting

2018-09-19T17:19:56Z

162.158.63.214: First pass explanation.

{{comic
| number = 2048
| date = September 19, 2018
| title = Curve-Fitting
| image = curve_fitting.png
| titletext = Cauchy-Lorentz: "Something alarmingly mathematical is happening, and you should probably pause to Google my name and check what field I originally worked in."
}}

==Explanation==
{{incomplete|Please edit the explanation below and only mention here why it isn't complete. Do NOT delete this tag too soon.}}

A illustration of several plots of the same data with curves fitted to the points, paired with conclusions that you might draw about the person who made them.

When modeling a phenomenon statistically, it is common to search for trends, and fitted curves can help reveal these trends. Much of the work of a data scientist or statistician is knowing which fitting method to use for the data in question.

In general, the researcher will specify the form of an equation for the line to be drawn, and an algorithm will produce the actual line.

* Linear: f(x) = mx + b

* Quadratic: f(x) = ax^2 + bx + c

* Logarithmic: f(x) = a*log_b(x) + c

* Exponential: f(x) = a*b^x + c

* Loess:

* Linear, No Slope: f(x) = c

* Logistic: f(x) = L / (1 + e^(-k(x-b)))

* Confidence Interval: not a type of curve fitting, but a method of depicting the predictive power of a curve

* Piecewise: Mapping different curves to different segments of the data. This is a legitimate strategy, but the different segments should be meaningful, such as if they were pulled from different populations.

* Connecting lines: Not useful whatsoever, but it looks nice!

* Ad-Hoc Filter: Drawing a bunch of different lines by hand. Also not useful.

* House of Cards: Not a real method, but a common consequence of mis-application of statistical methods: a curve can be generated that fits the data extremely well, but immediately becomes absurd as soon as one glances outside the training data sample range, and your analysis comes crashing down "like a house of cards". This is a type of _overfitting_

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[In a single frame twelve scatter plots with unlabeled x- and y-axes are shown. Each plot consists of the same data-set of approximately thirty points located all over the plot but slightly more distributed around the diagonal. Every plot shows in red a different fitting method which is labeled on top in gray.]

:[Caption above the plots:]
:'''Curve-Fitting Methods'''
:and the messages they send

:[The first plot shows a line starting at the left bottom above the x-axis rising towards the points to the right.]
:Linear
:"Hey, I did a regression."

:[The second plot shows a curve falling slightly down and then rising up to the right.]
:Quadratic
:"I wanted a curved line, so I made one with Math."

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Scatter plots]]
[[Category:Math]]
[[Category:Science]]

2019: An Apple for a Dollar

2018-07-13T16:04:51Z

162.158.63.214:

{{comic
| number = 2019
| date = July 13, 2018
| title = An Apple for a Dollar
| image = an_apple_for_a_dollar.png
| titletext = I'd like 0.4608 apples, please.
}}

==Explanation==
0.4608 * $2.17 = $1 (almost)

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

{{comic discussion}}

1997: Business Update

2018-05-23T18:53:09Z

162.158.63.214: /* Explanation */ spell "pillory"

{{comic
| number = 1997
| date = May 23, 2018
| title = Business Update
| image = business_update.png
| titletext = Our customers keep sending us their personal information, even though we've repeatedly asked them to stop. The EU told me I'm the heir to some ancient European throne that makes me exempt from the GDPR, but we should probably still try to fix that.
}}

==Explanation==
{{incomplete|Created by a MAGIC CEO - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic shows a meeting at Beret Guy's business (as seen in [[:Category:Beret Guy's Business|these other comics]]. As usual, those in the business demonstrate a misuse of business terminology and take strange happenings within the business in stride.

Though maintaining a semblance of business-saviness through the use of many corporate buzzwords, it becomes clear that what is normally metaphorical in a usually boardroom meeting is actually quite likely what is actually in development. The Quarterly Reports are probably physically attractive, though the business dealings they are reporting may be disastrous. There is likely a bunch of dollar bills in one of the office rooms. Stocks (pillory?) are being manufactured. At least one of their customers (a child?) is experiencing physical growth. Assets liquidated in a thermostat glitch may have been ice or some other material that melted; the kitchen sink producing original content may have been back flooding. The largest source of revenue is likely not producing much if any revenue at all; it can still be the biggest if there are no others.

The title text refers to the May 25 deadline to implement the European Union's {{w|GDPR|General Data Protection Regulation}}, this comic focuses on a business meeting about what the company is doing to prepare for it.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Beret Guy, Ponytail, Hairy, Hairbun and Megan sit around a table, left to right. Beret Guy and Megan are sitting on chairs at the ends. All others are behind the table with no visible chairs. All characters face Beret Guy]
:Beret Guy: Quarterly reports are looking good.
:Beret Guy: Our office is full of cash, we're producing stocks faster than ever before, and our customers are experiencing rapid growth.
:Beret Guy: Any Updates?

:[Closeup on Ponytail, facing left]
:Ponytail: Bad news: many of our assets were liquidated this morning due to a thermostat glitch.
:Ponytail: Good news: the sink in the kitchen has stopped producing original content.

:[Same as panel one, but characters are facing Megan]
:Beret Guy: How are our finances?
:Megan: Our biggest source of revenue is our ongoing project to transmute lead into gold.
:Megan: Our biggest expense is our project to transmute it back.

:[Closeup on Beret Guy, facing right, offset to the left of the panel. Two characters speak from off-panel right]
:Beret Guy: Lastly, any luck getting the girl from ''The Ring'' to stop showing up in our video conferences?
:From Right 1: No, but honestly, she's made some good contributions.
:From Right 2: Yeah, I think we should hire her.

{{comic discussion}}
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Beret Guy]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring Hairbun]]
[[Category:Beret Guy's Business]]

153: Cryptography

2017-11-11T13:19:05Z

162.158.63.214: If you feel this page is still incomplete, clarify HOW it is so when putting the incomplete tag back.

{{comic
| number = 153
| date = September 6, 2006
| title = Cryptography
| image = cryptography.png
| titletext = If you got a big keyspace, let me search it.
}}

==Explanation==
This comic refers to the study of {{w|cryptography}}. We can note the presence of the {{w|International Association for Cryptologic Research|International Association for Cryptologic Research (IACR)}} logo in the lectern, an association that organizes the most important conferences in the cryptology field. [[Cueball]], behind the lectern at the podium, is describing a proposed crypto system in which a computer program turns a very large number, called the "{{w|key (cryptography)|key}}," and a message into an encrypted form that can only be read by using the same key, based on the model of a {{w|Feistel cipher}}. Part of any Feistel cipher is the "round function," which determines how the key is applied to the original message; this is applied multiple times with a variety of tricks and techniques to ensure that the process can eventually be reversed. One common component of round functions is the {{w|S-box}}, a simple table that converts input bytes into output bytes, preferably in a way that doesn't correspond to any mathematical rules.

Here, the S-box would be implemented by doing the following (with the computer operation actually shown in the diagrams indicated in parentheses):

#Take the bitstring down (roll right by 1)
#Flip it (take its binary NOT)
#Reverse it (run the bits in the opposite order)

This would be run on each round of the cipher to further scramble the message for the next round. As the caption implies, the steps are based on a line from the {{w|Missy Elliott}} song ''{{w|Work It (Missy Elliott song)|Work It}}'': '''"I put my thing down, flip it and reverse it."''' As with any encryption system, there must be a way to decrypt the cipher text. In Missy Elliott's song, the phrase "I put my thing down, flip it and reverse it" is repeatedly played backward, sounding like gibberish. In the same way, steps to a Feistel cipher-based algorithm are executed in reverse to obtain the original plain text from a cipher text.

The {{w|Key space (cryptography)|keyspace}} for a cryptographic algorithm is the number of possible keys the algorithm can possibly accept. For example, {{w|Advanced Encryption Standard|AES-256}} has a keyspace of 2256 (roughly 1.1579209e+77) possible keys, simply because the algorithm specifies that each key is 256 bits wide. The title text is referring to "searching a keyspace," which is to say, simply trying every key until you find one that works. (For reference, a computer would require roughly the energy of a billion billion supernovas to even count to 2256, let alone actually try each one.) The precise wording, "If you got a big keyspace, let me search it" is, of course, another reference to the same song: "If you got a big **** let me search ya" (The word "penis" is censored by the trumpeting of an elephant).

===Inside references and real life shenanigans===

Cueball is banned from multiple conferences for similar pranks in [[541: TED Talk]]. In response to 541, {{w|PyCon}} organizers jokingly [http://pycon.blogspot.com/2009/02/randall-munroe.html announced] that Randall Munroe was banned from PyCon 2009 due to "last year's disgraceful keynote, 'Web Spiders vs. Red Spiders'." They also said they instructed their volunteers to refuse admission to him and "any stick figures who may attempt to register, particularly if they are wearing hats."

Messages on the PyCon-Organizers mailing list show that this joke was intended to get Randall to come to PyCon: (The links will only work if you're subscribed to the mailing list.)
:PyCon mentioned briefly in today's xkcd:
:http://xkcd.com/541/
:We've still never gotten Randall Munroe to actually attend, have we? Anybody want to take charge of twisting his arm this time? I think we can still offer him a "press pass" (free registration). [...] [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011224.html]
::An invite would seem most appropriate given the cartoon. :-)
::We could also have an official PyCon blog post confirming his ban... [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011225.html]
:::How about a public blog post LIFTING the ban and inviting him? [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011226.html]
::::Confirming the ban is far funnier... He's definitely a disturbing influence on programmers. [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011227.html]
:::::Agreed, especially if we invite him concurrently with confirming the ban. [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011239.html]
:::::(a few posts later)
:::::I'm happy to participate in actually throwing some thin guy out of the conference, and then get some graphics savvy person to animate a stick figure over that. :) [...][http://mail.python.org/mailman/private/pycon-organizers/2009-February/011274.html]
::::::here's a rough idea of what would show up if you invited him to actually do any speaking...
::::::http://www.youtube.com/watch?v=zJOS0sV2a24
::::::it's fairly long. he shows up in the beginning around 3:25. [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011275.html]
:::::::For the record, I did try to convince him to come when got the art for the tshirt last year. He didn't seem super psyched, but then again emotions are hard to read via IRC.
:::::::I love the idea of "officially" banning him, however. ;-) [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011241.html]
::::::::(a few posts later)
::::::::OK - posted to the PyCon blog, by the power vested in me as publicity chair. With Michael Foord's excellent sentence added.
::::::::Now let him know that since he's banned, he HAS to come. [http://mail.python.org/mailman/private/pycon-organizers/2009-February/011251.html]

==Transcript==
:[Randall Munroe (drawn as Cueball) stands behind a lectern on a podium in front of a large conference audience (consisting of Cueball heads), with a poster hanging beside him.]
:Randall: My cryptosystem is like any Feistel cipher, except in the S-Boxes we simply take the bitstring down, flip it, and reverse it.

:[The poster reads:]
:: Decryption
:: <code>01101010</code>
:: <code>   >></code>
:: <code>00110101</code>
:: [inverter symbol]
:: <code>11001010</code>
:: [crossed arrows]
:: <code>01010011</code>

:[Caption below the crowd:]
:I've been barred from speaking at any major cryptography conferences ever since it became clear that all my algorithms were just thinly disguised Missy Elliott songs.

{{comic discussion}}

[[Category:Comics featuring Randall Munroe]]
[[Category:Comics featuring Cueball]]
[[Category:Public speaking]]
[[Category:Banned from conferences]]
[[Category:Cryptography]]